JP2002283248A - Fastening tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastening tool capable of optimal fastening without damaging a fastening member even if there is inconvenience in assembling even in any fastening member. SOLUTION: This fastening tool has a fastening determining part 9 for outputting a stopping command to a motor control part 10 at unexceeded time by determining whether or not fastening torque exceeds member determining torque, and outputting the stopping command to the motor control part 10 when a torque variation becomes about 0 or less by continuing output of a rotation command to the motor control part 10 at exceeding time. The fastening determining part 9 continues the output of the rotation command to the motor control part 10 when the fastening torque does not exceed the inconvenience determining torque by determining whether or not the fastening torque exceeds the inconvenience determining torque when trying to output the stopping command to the motor control part 10, and outputs the stopping command to the motor control part 10 when the fastening torque exceeds the inconvenience determining torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tightening tool used for tightening screws and bolts, such as a drill driver and a wrench.

[0002]

2. Description of the Related Art [Structure of impact tightening tool]
For screw tightening and bolt tightening work at construction sites and assembly plants, etc., a tightening tool that can quickly perform tightening work using the rotational force of the motor is routinely used to improve workability. In recent years, among the tightening tools, in order to further improve workability, the rotation of the motor is converted into a hammer impact, and the tightening work is performed with the strong impact force, so that the speed is reduced. Impact tightening tools that can obtain higher torque than rotary tools using only machines are becoming a trend.

FIG. 23 is a block diagram showing the structure of the impact tightening tool. As shown in the vicinity of the center of the figure, the motor 1 as a driving means and the rotation of the motor 1 are reduced at a predetermined reduction ratio. The speed reducer 2 as a transmission mechanism, the hammer 3 whose rotation of the motor 1 is transmitted through the speed reducer 2, the anvil 4 hit by the hammer 3, and the impact force generated by the hit are transmitted to screws and bolts. Output shaft 5 to transmit
The impact by the anvil 4 is generated when a force of a predetermined value or more is applied between the hammer 3 and the anvil 4 and the hammer 3 rotates with respect to the anvil 4 by a predetermined amount or more.

The fastening tool has a frequency generator 6 as a means for detecting the rotation speed of the output shaft 5 for generating a frequency signal proportional to the rotation speed of the motor 1, and a frequency signal generated by the frequency generator 6. Waveform shaping,
A waveform shaping circuit 7 that outputs a pulse signal having a pulse width corresponding to the rotation speed of the output shaft 5, and a torque estimation that estimates how much tightening torque has been generated by performing arithmetic processing based on the pulse signal. Unit 8 and a limit torque setting unit 14c for setting a desired tightening torque. The set torque set by the limit torque set unit 14c and the estimated tightening torque obtained by the torque estimation unit 8 And a tightening determination section 9a that outputs a control command to the motor 1.

More specifically, the tightening determination section 9a
Is configured to output a stop command to stop the motor 1 via the motor control unit 10 and the motor control circuit 11 when the estimated tightening torque exceeds the set torque. Outputs a rotation command or a stop command to the motor control circuit 11 in response to the pull-in of the trigger 12 when the stop command is not received from the tightening determination unit 9a to rotate or stop the motor 1. When the stop command is received, the motor 1 is prevented from rotating until the trigger 12 is once released.

The motor control circuit 11 includes, for example, a pulse width modulation control (PWM control) circuit.
Rechargeable battery 1 for nickel-cadmium, nickel-hydrogen, etc.
3, and controls the motor 1 in response to a control command from the motor control unit 10.

[Problems of Conventional Impact Tightening Tool] However, in the above-described impact tightening tool, the target set torque must be determined by the limit torque setter 14c, so that the appropriate tightening torques are substantially the same. In the case of tightening a plurality of members, the work can be continued without changing the set torque,
When tightening a plurality of members with different appropriate tightening torques, it is necessary for the operator to change the set torque before each tightening operation according to the members, which causes a reduction in work efficiency. I was In addition, there is a problem that incorrect selection of the set torque may cause insufficient tightening or damage to the tightening member.

[0008] Therefore, the present inventors have found that the lower striking number theta _n in FIG. 24 - as shown in the torque T characteristics tightening, the tightening member and the fastened member such as a screw abuts, fastening The intention was to use a response inherent in the tightening operation, in which the increase in the applied torque T reaches a plateau. More specifically, when a tightening member such as a screw starts contacting the tightened member, a tightening torque T
24, and accordingly, the number of impacts θ _n − in the upper row of FIG.
The torque fluctuation amount _Tq characteristic rises sharply and settles to a constant value. However, when the tightening of the tightening member and the tightened member is completed and the tightening member stops rotating, it rapidly drops to 0. We wanted to use the response.

[0009] How to use the amount of torque fluctuation prior art utilizing] the amount of torque fluctuation T _q are known from previously, for example, in "How clamping bolt" in JP 61-8284 JP Is, as shown in FIG. 25, a torque average value S (K) for an arbitrary number of samplings is obtained, and a difference G (G) between the average value S (K) and the immediately preceding average value S (K-1) is obtained. (K) is obtained, and when the difference G (K) becomes smaller than a threshold value MS, the method of stopping the bolt tightening is disclosed.

Considering that the tightening is firmly completed, instead of stopping the tightening of the bolt when the value becomes smaller than the threshold value MS as in the related art, the torque variation _Tq is reduced. It should be better to stop the tightening when it reaches 0. Nevertheless, the background in which the prior art employs the threshold value MS is that the fastening member or the member to be fastened may be a strong member made of a metal material or the like,
It is presumed that consideration is given to the case where a brittle member, such as a resin-based material, that may be damaged by excessive tightening torque is tightened.

[0011]

Therefore, in the prior art, if the threshold value MS is set to a high value in consideration of the tightening of the resin-based member, the resin only needs to be engaged. Unlike metal members, insufficient tightening may occur when metal members are required to be firmly tightened. However, in consideration of tightening metal members,
When the threshold value MS is set to 0 and the resin-based member is tightened, that is, when the torque variation _Tq becomes 0, when the tightening of the resin-based member is stopped, as shown in the center of FIG. In addition, there is a problem in that the resin member is stopped at a point after the maximum point of the tightening torque T, and the resin-based member is damaged.

The response shown in FIGS. 24 to 26 is very ideal. Actually, the screw grooves are not uniform, or the member sandwiched between the bolt and the nut is slightly curved. As shown in FIG. 27, the tightening torque T temporarily increases due to slipping of the center axis of the bolt and nut, entrainment of dust, or scraping off of baking paint on the surface of the screw hole. There is. Nevertheless, in the above-described conventional technique, when the difference G (K) corresponding to the torque fluctuation amount _Tq becomes smaller than the threshold value MS, the bolting is stopped. without reaching to a point which is theta ₃ a completion point, first in terms of the amount of torque fluctuation T _q is 0 when theta _1, there, it would have been stopped tightening, the tightening in an incomplete state There was a problem that it ended.

The present invention has been made in view of the above-mentioned problems, and has as its object the purpose of using any kind of fastening member and having some inconvenience in assembly. An object of the present invention is to provide a tightening tool capable of performing optimum tightening without damaging the tightening member.

[0014]

Therefore, the inventors of the present application first consider the optimal tightening of the resin-based member, and not the torque fluctuation amount but the change in the torque fluctuation amount. It has been found that by stopping the tightening when the torque fluctuation rate becomes zero, an optimum tightening state can be obtained without damaging the resin-based member. Means for tightening the resin-based member using the torque fluctuation rate is as follows:
2. The motor according to claim 1, further comprising: a motor controller configured to control rotation and stop of the motor; and a torque estimator configured to estimate a tightening torque of an output shaft of the motor. A tightening tool for performing a tightening operation of a screw, a bolt, or the like, wherein a torque fluctuation amount, which is a ratio of a change in the tightening torque to a change in the rotation angle or time of the motor, is obtained, and the motor When the torque fluctuation rate, which is the rate of the change in the torque fluctuation amount with respect to the change in the rotation angle or time, is obtained, and when the torque fluctuation rate exceeds an arbitrarily determined judgment start reference value and becomes about 0 or less, And a tightening judging means for judging that the tightening of the screw or the like is completed and outputting a stop command to the motor control means.

Next, the inventors of the present application consider that optimal tightening is performed using any kind of tightening member, and the torque variation rate is used for the resin-based member, while the metallic member is used for the metal-based member. We considered using the torque fluctuation. The means for this is the means described in claim 2, comprising a motor control means for controlling the rotation and stop of the motor, and a torque estimating means for estimating the tightening torque of the output shaft of the motor. ,
A tightening tool for performing a tightening operation such as a screw or a bolt made of a resin-based member or a metal-based member using a rotational force of the motor, wherein the tightening tool is configured to perform a tightening operation with respect to a change in a rotation angle or time of the motor. A torque fluctuation amount, which is a rate of change in torque, is determined, and a torque fluctuation rate, which is a rate of change in the torque fluctuation amount with respect to a change in the rotation angle or time of the motor, is determined, and the torque fluctuation rate is determined arbitrarily. After the reference value is exceeded, when it becomes about 0 or less, whether the tightening torque exceeds the member determination torque which is a boundary value between the maximum tightening torque of the resin-based member and the maximum tightening torque of the metal-based member. If it does not exceed the member determination torque, it is determined that the tightening of the resin-based member has been completed, and a stop command is output to the motor control means, while the member determination torque has been exceeded. In this case, the output of the rotation command is continued to the motor control means, and when the torque fluctuation amount becomes about 0 or less, it is determined that the tightening of the metal member has been completed, and the motor control means is notified. The present invention is characterized in that a tightening determination means for outputting a stop command is provided.

Next, the inventors of the present application deal with a case where the tightening torque T temporarily increases due to an assembling defect caused by an irregular thread groove, a deviation of the center axis of a bolt and a nut, or the like. Therefore, when it is determined that the tightening has been completed, the tightening torque may be temporarily reduced due to an assembly defect or the like. Judgment is made as to whether or not the malfunction determination torque is set to be slightly larger than the maximum torque when the applied torque increases, and if the malfunction determination torque is not exceeded,
While it is determined that the failure or the like has occurred and the rotation command is continuously output to the motor control means, if the failure determination torque is exceeded, it is determined that the screw or the like is properly tightened. A means for tightening determination for outputting a stop command to the motor control means is provided.

When tightening only metal members,
Motor control means for controlling rotation and stop of the motor,
A torque estimating means for estimating a tightening torque of an output shaft of the motor, wherein a tightening tool for tightening a screw, a bolt, or the like using a rotational force of the motor is provided. A torque variation, which is a ratio of a change in the tightening torque to a change in angle or time, is determined. After the torque variation exceeds an arbitrarily determined reference value, about 0%
When the tightening torque becomes less than or equal to a malfunction determination torque that is set to be slightly larger than the maximum torque when the tightening torque temporarily increases due to an assembly failure or the like. If it does not exceed the malfunction determination torque, it is determined that the malfunction or the like has occurred, and the output of the rotation command to the motor control means is continued, while the malfunction determination torque has been exceeded. in case of,
The means according to claim 4, further comprising a tightening determination unit that determines that the screw or the like is properly tightened and outputs a stop command to the motor control unit. .

[0018] However, because of the unchanged a malfunction determination torque in the above-described means, the torque at the completion point tightening (theta ₃ points) shown in FIG. 27, when less than the failure determination torque tightening is completed In some cases, the tightening operation may be continued even though it is performed. Then, in order to solve such a problem, the inventors of the present application provide a failure determination that can freely change the failure determination torque of the tightening determination unit with respect to the means described in claim 3 or 4. A means according to claim 5 is provided, wherein a torque setting means is provided.

However, according to this means, when a member having a small tightening torque at the time of completion of tightening and a member having a large tightening torque are mixed to perform a tightening operation, the members are adjusted according to the respective members.
Since it is necessary to set the failure determination torque, there is a possibility that the working efficiency is reduced. Therefore, the inventors of the present application have set forth claims 3 or 4 to solve such a problem.
In the means described in (1), the total number of rotations of the motor exceeds the minimum required number of rotations, which is the determined number of rotations, in the number of times required to complete the tightening of all the members to be tightened such as the screws. In the case where the rotation speed does not exceed the determined rotation speed, the maximum torque is obtained from the tightening torques from the start to the present, and the tightening determination means is determined to be slightly larger than the maximum torque. While setting the failure determination torque, if the rotation speed exceeds the determination rotation speed, to determine the maximum torque in the tightening torque from the start to the determination rotation speed, so as to be slightly larger than the maximum torque, 7. A malfunction determination torque automatic setting means for setting a malfunction determination torque of the tightening determination means.
The measures described in the above are also proposed.

However, according to this means, if the estimated tightening torque immediately after the start of the motor is too small due to some disturbance or vice versa, the estimated torque is adjusted to the magnitude of the estimated tightening torque. Since the failure determination torque is set to be too small or too large, there is a possibility that the fastening is stopped or the fastening operation is continued without reaching the fastening completion point. In order to solve such a problem, the inventors of the present application have proposed a means described in claim 3 or claim 4 in which the total number of rotations of the motor is reduced by the tightening of all the tightening target members such as the screws. In the required number of times until the attachment is completed, it is determined whether or not the rotation speed exceeds the minimum required rotation speed, that is, the determination rotation speed.If the rotation speed does not exceed the determination rotation speed, the malfunction determination torque of the tightening determination unit is reduced. On the other hand, if the initial setting torque is arbitrarily determined, if the rotation speed exceeds the determined rotation speed, the maximum torque is obtained from the tightening torque from the start to the determination rotation speed, and is slightly larger than the maximum torque. The provisional set value is determined so as to satisfy the above condition, and it is determined whether the provisional set value is equal to or more than the initial set torque. Toss On the other hand, if the torque is less than the initial set torque, it is determined whether the tentative set value is equal to or less than an arbitrarily determined allowable lower limit torque. Is set as the allowable lower limit torque, and when the torque is larger than the allowable lower limit torque, a malfunction determination torque automatic setting unit that sets the temporary set value is provided. I decided that.

On the other hand, the inventors of the present application have completed the above-mentioned tightening with respect to a means different from the means described in claim 3 and the means described in claim 1 or 2. Is determined, whether the total number of rotations of the motor exceeds the minimum required number of rotations, which is the minimum required number of rotations, in the number of times required to complete the tightening of all the members to be tightened such as the screws. If the rotation speed does not exceed the determined rotation speed, it is determined that a failure in assembly has occurred, and the output of the rotation command to the motor control means is continued while the rotation speed exceeds the determination rotation speed. 9. A tightening judging means for judging that the screw or the like is properly tightened in the case of output and outputting a stop command to the motor control means.
It is pointed out that the means described in (1) can also cope with the case where the tightening torque T temporarily increases.

When only metal members are tightened,
A tightening tool that includes a motor control unit that controls rotation and stop of a motor, and performs a tightening operation of a screw, a bolt, or the like by using a rotational force of the motor. A torque fluctuation amount, which is a ratio of a change in the tightening torque to a change, is obtained. When the torque fluctuation amount becomes about 0 or less after exceeding an arbitrarily determined reference value, a total rotation speed of the motor is determined. However, in the number of times required for the tightening of all the tightening target members such as the screws to be completed, it is determined whether or not the number of rotations exceeds a minimum required number of rotations, that is, the determined number of rotations. It is determined that an assembly failure has occurred, and the rotation command is continuously output to the motor control means.If the rotation speed exceeds the determination speed, the screws and the like are properly tightened. Is determined to have been It may be employed means described in claim 9 characterized by having a clamping determination means for outputting a stop command to the motor control unit.

However, in this means, since the determined rotation speed is not changed, the tightening member which completes the tightening by a smaller number of times than the determined rotation speed may have the tightening completed. Nevertheless, there have been cases where the fastening operation is still continued. Then, in order to solve such a problem, the inventors of the present application have determined that the determination rotation speed of the tightening determination unit can be freely changed with respect to the unit described in claim 8 or 9. The means set forth in claim 10 is provided with a rotational speed setting device.

The inventors of the present invention are directed to any one of claims 1 to 10 in order to cope with a case where a fastening member that has already been fastened is erroneously tightened. For the performed means, the torque fluctuation amount or the torque fluctuation rate,
When the determination start reference value is not exceeded, the tightening torque is the additional tightening determination torque set to the smallest tightening torque among a plurality of maximum tightening torques in all the tightening target members such as the screws. It is determined whether or not the torque exceeds the retightening determination torque.If the torque does not exceed the retightening determination torque, it is determined that the screws and the like are properly tightened, and the output of the rotation command to the motor control unit is continued. 12. The method according to claim 11, further comprising: a tightening determination unit that determines that retightening is performed when the torque exceeds the retightening determination torque and outputs a stop command to the motor control unit. We decided to adopt the means that was given.

Also, in the above means, it has been noted that when the vehicle is stopped halfway due to an erroneous determination, it is necessary for the operator to pull the trigger again in order to continue the tightening operation, which is troublesome. In order to solve such a problem, the inventors of the present application have requested the motor control unit to receive a stop command from the tightening determination unit in response to the unit described in any one of claims 1 to 11. 13. The means according to claim 12, further comprising: starting time measurement, starting the motor again when a predetermined time arbitrarily determined has elapsed with a trigger operated by an operator being pulled. Was adopted.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] (Structure of Impact Tightening Tool of the Present Embodiment) Next, each means for solving the above-mentioned problems will be described as a more specific embodiment. This will be described in detail below. First, regarding the means described in claim 1, as described above, the inventors of the present application have applied to a resin-based member not a torque variation but a torque variation rate that is a change in the torque variation. It has been found that by stopping the tightening at the time when the value becomes 0, the optimum tightening state can be obtained without damaging the resin-based member.

The structure of the impact tightening tool for that purpose is as follows.
As shown in FIG. 1, a limit torque setting device 14c for setting a desired tightening torque operated by an operator is eliminated in addition to the configuration of the conventional impact tightening tool shown in FIG. , Limit torque setting device 1
4c and the estimated tightening torque obtained by the torque estimating unit 8 are compared with each other, and instead of the tightening determining unit 9a that outputs a control command to the motor 1,
On the basis of the estimated tightening torque obtained by the torque estimating unit 8, a tightening determining unit 9 is provided which performs a predetermined calculation described later to automatically determine the completion of the tightening.

(Steady operation of impact tightening tool)
The normal operation of the impact tightening tool will be described with reference to FIGS. 1 and 2.
Is retracted (step A1), the retraction is detected by the motor control unit 10, and the motor control circuit 11
The motor control circuit 11 controls the rotation of the motor 1 based on the command (step A).
2). When the motor 1 rotates upon receiving the PWM output from the motor control circuit 11, the frequency generator 6 generates a frequency signal proportional to the number of rotations, and the waveform shaping circuit 7
Outputs a pulse signal having a pulse width corresponding to the rotation speed of the output shaft 5 (the rotor of the motor 1).

Next, based on the pulse signal, a hit detection process described later is performed (step A3), and the worker releases the trigger 12 or, in step A3, the tightening determination unit 9 causes the motor control unit to execute. When a shut-off command is output to the motor 1 (step A4), the motor control unit 10 outputs a stop command to the motor control circuit 11, and the motor control circuit 11 having received the stop command causes the motor control circuit 11 to PW
The M output is stopped, the stop control of the motor 1 is performed (step A5), and a standby state is prepared for the next operation (step A6).

(Detection of Impact in Impact Tightening Tool of the Present Embodiment) The above-described impact detection processing in step A3 is performed by the torque estimating unit 8 in the torque shaping circuit 7 as shown in FIGS. Whether the input pulse signal changes from low to high or high
An interrupt is generated when the state changes from "L" to "Low", that is, when a pulse edge occurs, and the pulse edge is counted (step B1), and the frequency generator as the rotation speed detection means is substituted for the rotation angle detection means. Then, by obtaining the pulse width w [k] from the difference between the two count values before and after, the corresponding value of the rotational speed (corresponding to the reciprocal of the speed), which is the original function, is detected (step B2).

Then, according to the following equations (1) and (2), average pulse widths w _a1 and w _a2 obtained by moving average of the pulse width w [k] by J and K, respectively, are obtained. , (3)
As shown in the equation, the speed fluctuation amount v [k] is obtained from the difference between the average pulse widths obtained by subtracting _wa2 from _wa1 .

(Equation 1)

(Equation 2)

(Equation 3)

Then, based on the following equation (4), an acceleration fluctuation amount a [k], which is a difference in the speed fluctuation amount, obtained by subtracting the value L moved from the speed fluctuation amount v [k] is calculated. I have. The acceleration fluctuation amount a [k] serves as a band-pass filter, and allows accurate acceleration fluctuation without being affected by noise or the like from PWM. still,
L shown in equation (4) is determined, for example, so as to obtain the total number of pulses generated by one rotation of the motor, that is, the value one rotation before (step B3).

(Equation 4)

Next, the torque estimating section 8 estimates that the impact has occurred when the acceleration variation a [k] obtained as described above exceeds an arbitrarily determined threshold. If it is estimated that the impact has occurred (step B
4) Tightening determination processing described later is performed (step B5). In addition, the inventors of the present application have a method of estimating the occurrence of a blow by detecting a blow sound with a microphone. However, there is a case where the blow is erroneously estimated by the vibration sound of the motor 1 and the reduction gear 2, He points out that the above estimation method is more desirable.

(Torque Estimation Method in the Present Embodiment) Next, in describing the tightening determination processing in step B5 described above, first, a method for estimating the tightening torque will be described. As an example of the method, the inventors of the present application, in Japanese Patent Application No. 11-166024, the rotational speed of the motor,
A method for estimating the tightening torque from the rotation amount of the motor during the impact is proposed. This method is derived from the balance of kinetic energy for each impact, and is based on the relationship that the energy consumed in tightening is approximately equal to the energy applied to the anvil provided on the output shaft by the impact of the hammer. And a method for estimating the tightening torque.

More specifically, as shown in FIG. 4, the rotation angle θ of the output shaft 5 and the tightening torque T are represented by a nonlinear function of T = τ (θ). integrated value at the corner θ is, whereas the energy consumed by the tightening, the square of the value of the rotational speed ω of the output shaft, the half value of the value obtained by multiplying the inertia moment J _a of the anvil Since the energy given to the anvil by the impact of the hammer is obtained, the estimated tightening torque can be obtained by making these two energies equivalent.

For example, referring to FIG.
Is the rotation angle θ₁, Θ_Two…, Θ_nIf it occurs in
As shown in the following equation (5), the nonlinear function τ is
[θ_n, Θ _{n + 1}Energy E obtained by integrating_nTo
Rotation angle between impact φ_n(= Θ_{n + 1}−θ_n) Is the interval
[θ_n, Θ_{n + 1}Average torque T_naBecomes

(Equation 5)

On the other hand, as shown in (6) below, from the square of the value of the rotational speed omega _n in the striking time of occurrence theta _n, the half value of the value obtained by multiplying the inertia moment J _a of the anvil The energy E _ni given to the anvil by the impact of the hammer generated at the time of the impact occurrence θ _n .

(Equation 6)

[0038] In this case, energy E _n and the energy E _ni
Are equivalent, the equation (6) is substituted into the equation (5), the average torque T _na is called the estimated tightening torque T _nh, and the following equation (7) is obtained. , this equation can be determined torque T _nh with estimated tightening (hereinafter referred to as torque T _h with estimated tightening). In addition, the inventors of the present application may use a torque sensor, estimate the current amount or voltage amount of the motor 1, the advancing angle of the output shaft 5, and the rebound amount of the hammer 3 in addition to the torque estimation method. Is also good.

(Equation 7)

(Tightening Judgment in Impact Tightening Tool of this Embodiment) Taking the above torque estimation method into consideration, FIG.
The tightening determination process in step B5 described above will be described with reference to FIG.
Reads the count C _i between the striking, according to (8) below, and determines a rotation angle phi _n between blow multiplying the rotation angle of the count C _i and 1 per count output shaft 5.
The rotation angle of the output shaft 5 per one count from 2 [pi, the output shaft 5 becomes a value obtained by dividing the total count C _a counted by the torque estimating unit 8 during one rotation (step C1).

(Equation 8)

Further, according to (9) below, the rotation angle 2 [pi / C _a of the output shaft 5 per one count, by dividing the average pulse width w _aa, rotational speed in the striking time of occurrence theta _n omega _n Is calculated (step C2).

(Equation 9)

Then, according to the equations (8) and (9),
The estimated tightening torque can be obtained by calculating the rotation angle φ _n between impacts and the rotational speed ω _n at the time of impact occurrence θ _n according to the above equation (7) (step C3). . Next, the torque estimating unit 8 outputs the estimated tightening torque _Th to the tightening determining unit 9, and the tightening determining unit 9 first calculates the tightening torque Th according to the following equations (10) and (11), respectively. the estimated tightening torque T _h [k] seeking the M and N moving average of the torque with average tightening calculated T _a1, T _a2,
As shown in the equation (3), the torque fluctuation amount _Tq [k] is obtained from the difference between the average tightening torques obtained by subtracting _Ta2 from _Ta1 .

(Equation 10)

[Equation 11]

(Equation 12)

Next, the tightening determination section 9 calculates the torque fluctuation amount T _q [k] as O according to the equations (13) and (14), respectively.
The average torque fluctuation amounts T _qa1 and T _qa2 obtained by moving average of P and P pieces are obtained, and as shown in equation (15),
_The torque fluctuation rate T _v [k] is obtained from the difference in the average torque fluctuation amount obtained by subtracting T _qa2 from _qa1 (the above-described step C
4). Incidentally, the inventors of the present application is, when determining the amount of torque fluctuation T _q or torque variation ratio T _v, but may be simply to take this value and the difference between the previous value, considering the noise, also He points out that it is better to take a moving average.

(Equation 13)

[Equation 14]

(Equation 15)

[0043] Here, the torque T _h with estimated tightening against the striking number theta _n, the amount of torque fluctuation T _q, with reference also to FIG. 6 showing the transition of the torque variation ratio T _v, when describing the step C4 after the treatment, tightening If the calculated torque fluctuation rate T _v exceeds the determination start reference value A arbitrarily determined in consideration of noise or the like (step C5) and becomes 0 or less (step C6) Then, a stop command is output to the motor control unit 10 to perform a shut-off process for stopping the rotation of the motor 1 (Step C7). The attachment determination process is terminated.

As described above, the point where the torque fluctuation rate _Tv becomes 0 is slightly before the maximum tightening torque _Tmax , and the tightening operation is stopped at the tightening completion point to tighten the resin member. Tightening can be completed without breaking by the attachment. When the point at which the torque fluctuation amount _Tq becomes zero is seen, it exceeds the maximum tightening torque _Tmax , and it goes without saying that the member is destroyed. Further, the inventors of the present application is, reason for providing the determination start criterion value A, and it initially tightening showing a torque variation ratio T _v is 0, because it may becomes 0 by noise or the like, such a case This is because it is necessary to eliminate.

[Second Embodiment] (Basic Concept of the Second Embodiment) Next, the means described in claim 2 will be described. Since we were able to provide an impact tightening tool that can perform optimal tightening on members, we next thought that optimal tightening could not be performed using any type of tightening member. It was conceived to stop the tightening of the member when the torque fluctuation rate T _v became 0, while stopping the tightening of the metallic member when the torque fluctuation amount became 0.

[0046] For this purpose, but must be carried out of the determination is metallic member or a resin member, as a method for such determination, the inventors have found that the torque T _{ma x} maximum tightening Paying attention to the differences depending on the members, examining the maximum tightening torque _Tmax of various resin-based members and metal-based members, the largest one among a plurality of maximum tightening torques _Tmax in the resin-based member, the boundary between those smallest among the plurality of maximum tightening torque T _max in the metallic member, the member determined torque the threshold value is, depending on whether the estimated tightening torque T _h is more than the member determination torque It is proposed to judge the members.

(Tightening Judgment in Impact Tightening Tool of the Present Embodiment) More specifically, it is the same as the tightening judging process shown in FIG. 8, (step C1) performs a calculation of the rotation angle phi _n between blow, performs calculation of the rotational speed omega _n in the striking time of occurrence theta _n (step C2), to estimate the tightening torque T (step C3 ). Then, the fastening determination unit 9
Is the estimated tightening torque T calculated in step C3.
_{From h} , a torque fluctuation amount _Tq and a torque fluctuation rate _Tv are calculated (step C4).

Here, when tightening the resin-based member,
Shots θ_nTightening torque T for_h, Torque fluctuation
T_q, Torque fluctuation rate T_v8 (a) showing the transition of
The processing after step C4 will be described.
The tightening determination unit 9 of the first embodiment determines that the torque fluctuation rate T_vTighten
An attachment determination is made (step D1). Soshi
Thus, similarly to the first embodiment, the torque fluctuation rate T_vBut
Exceeding the arbitrarily determined reference value A (step C
5) The fastening completion point θ of the resin-based member that has become 0 or less._r
(Step C6), the estimated tightening torque T_h
Is the member determination torque T ₁Judge whether or not
Member determination torque T₁(Step D
2) If it is determined that the resin-based member is
(Step C).
7).

On the other hand, in step D2, FIG.
As shown in FIG.₁Exceeds
In this case, it is determined that metal-based
Tightening completion point θ for grease-based members_rStop tightening with
Continue to tighten as the feet are formed.
The mode shifts to the constant mode (step D3), and the torque variation T _q
Of completion of tightening θ of metal-based members where_mBecame
Sometimes (step D4), a shut-off process is performed.
(Step C7), the torque fluctuation amount T _qIs 0
If not, continue tightening and check the tightening
End the process.

[0050] Thus, in the impact tool tightening of the present embodiment, initially tightening performed determination tightening with a torque variation ratio T _v, the completion point tightening theta _r of resin member when it is determined that reaches the torque T _h with estimated tightening is, if it exceeds the member determination torque T ₁ continues the tightening is determined that tightening the metallic member, the torque fluctuation amount T performing determination fastening using _q, when it is determined to have reached the completion point tightening theta _m of metallic member, since thereby performing the shut-off, using any fastening member Also, an optimum tightening state can be obtained without damaging the tightening member.

The other configurations and operations are the same as those in the first embodiment, and therefore will not be described here. In the following description of each embodiment,
Similar processing is described in FIG. 7 used in the description of the present embodiment.
As described above, the same reference numerals are given, and the frames and arrows are indicated by dotted lines to simplify or omit the description.

[Third Embodiment] (Basic Concept in This Embodiment) Next, the means described in claim 3 will be described. An impact tightening tool that can obtain an optimum tightening state even with a simple tightening member can be provided. Therefore, as shown in FIG. Tightening completion point θ shown
Without reaching up to _3, first the torque variation T _q (torque variation ratio T _v also applicable) where the in terms of 0 when theta _1, was Shiryo whether not to address the problem of stopping the tightening Note that, as shown in the figure, when the tightening torque T temporarily increases due to the problem, the maximum torque is extremely often smaller than the tightening torque T at the tightening completion point. did.

Then, the inventors of the present application examine the maximum torque in the case where the tightening torque T temporarily increases for each of various problems based on such a point of interest, and determine a plurality of maximum torques in the problem. than the largest torque among, to be slightly a large torque, the defect determination torque becomes the threshold value provided, depending on whether the torque T _h with estimated tightening exceeds the defect determination torque, with the estimated tightening torque T _h
Is proposed to determine whether the rise is due to sitting or malfunction.

[0054] More specifically (in the present embodiment determines the tightening of the impact fastening tool), and were as tightening determination process shown in FIG. 9, the torque T _h etc. With the estimated tightening against the striking number theta _n With reference to FIG. 10A showing the transition, the operation in the case of tightening the resin-based member will be described. First, the torque fluctuation rate _{Tv and the} like are calculated (steps C1 to C4),
Initially tightening, a determination tightening torque variation ratio T _v (step D1), when the number of striking becomes theta _1, the torque variation ratio T _v is already exceeds the determination start reference value A (step C
5), and since 0 becomes less (step C6), the torque T _h with estimated tightening is determined whether exceeds a member determination torque T _1, since no more than the member determination torque T ₁ (step D2) It is determined that the resin-based member is tightened.

At this time, the tightening determination unit 9 of the present embodiment
Estimated tightening torque T _h is, determines whether or not more than a defect determination torque T _2, because does not exceed the fault determination torque T ₂ (step E1), determines that some trouble has occurred, The torque fluctuation rate _Tv is cleared (step E2), the tightening is continued, and the tightening determination processing is ended. When the number of impacts is θ ₂ , the torque fluctuation rate T _v is equal to or less than 0, but does not exceed the determination start reference value A (step C5). The fastening determination process is terminated.

Meanwhile, if the number of striking becomes theta _r, the torque variation ratio T _v exceeds the previously determined starting reference value A (step C5), and since has become 0 or less (step C6), again estimated tightening urging torque T _h is, determines whether or exceeds a member determination torque T _1, since no more than the member determination torque T ₁ (step D2), it is determined that tightening the resin member. Then, the torque T _h with estimated tightening, it is determined whether the exceeds the defect determination torque T _2, since it exceeds the defect determination torque T ₂ (step E1), without bug occurs, clamping It is determined that the attachment member is properly tightened (seated), and a shut-off process is performed (step C7).

[0057] When tightening the metallic member shown in FIG. 10 (b), when a completion point tightening theta _r of resin member, the torque T _h with estimated tightening is member determination torque T ₁ since more than (step D2), and shifts to a torque fluctuation amount determination mode (step D3), when it is complete clamping points theta _m of metallic members which the torque variation T _q is 0 or less (step D4) , torque T _h with estimated tightening is, problem determination torque T ₂
Is determined, and the malfunction determination torque T is determined.
When the number exceeds ₂ (step E1), a shut-off process is performed (step C7).

As described above, in the impact tightening tool according to the present embodiment, the torque fluctuation rate _Tv or the torque fluctuation amount _Tq.
There is estimated tightening torque T _h when it becomes 0 or less, when exceeding the defect determination torque T _2, because is adapted to perform shutoff, even slight defects in assembly, optimal It is possible to perform a proper tightening. Note that other configurations and operations are the same as those of the above-described embodiments, and therefore will not be particularly described here.

[0059] Fourth Embodiment (Basic concept of the present embodiment) the present inventors have found that, in the third embodiment described above, by employing the malfunction determination torque T _2, some assembling Although an impact tightening tool capable of performing optimum tightening can be provided even if there is a problem, the tightening completion points θ _r and θ _m can be provided because the malfunction determination torque T ₂ is invariable. estimated tightening torque T _h at is, if Shimezukeru the malfunction determination is smaller than the torque T ₂ design outside tightening member, despite the tightening is completed, operation tightening In addition, there was a risk of being continued.

[0060] On the other hand, completion point tightening θ _r, at θ _m previously, the estimated tightening torque T _h when the torque variation ratio T _v and the like has become 0,
If the defect determination torque T ₂ Shimezukeru a larger design outside tightening member than or subjected to any excessive noise,
If it becomes larger than the defect determination torque T ₂ are, despite the tightening is not completed, there is a fear that stops operating clamping. Therefore, the inventors of the present application
In order to solve the above problems, it proposes a means according to claim 5 that can change the defect determination torque T _2.

(Structure of Impact Tightening Tool of the Present Embodiment) The specific structure of the impact tightening tool for that purpose is as follows.
Be as shown in FIG. 11, the configuration of a conventional impact fastening tool shown in FIG. 1, is connected to the tightening judging unit 9, it is possible to change the defect determination torque T _2, fault determination torque A setting device 14a is provided. This defect determination torque setter 14a, for example by using a variable resistor or the like, it suffices to be able to set fault determination torque T ₂ freely.

[0062] Thus, by providing the setting unit 14a, the work site worker, according to the frangible fastening member or rugged member of interest, to perform the setting of each said defect determination torque T ₂ Therefore, the above-mentioned non-stop or halfway stop can be avoided, and an optimum tightening state can be obtained. Note that other configurations and operations are the same as those of the above-described embodiments, and therefore will not be particularly described here.

[Fifth Embodiment] (Basic Thought in This Embodiment) The present inventors provided the failure determination torque setting device 14a in the above fourth embodiment, so that the out-of-design In the case of tightening the tightening member or even when excessive noise is applied, the above-described non-stop or halfway stop could be avoided, but a member having a small tightening torque and a member having a large tightening torque at the time of completion of tightening are required. If mixed to perform tightening operation, since in accordance with the member of each, it is necessary to set the failure determination torque T _2, there may result a reduction in working efficiency.

On the other hand, the inventors of the present application have repeated trial and error to find a clue that can cope with such a problem, and as shown in FIG. When the torque T increases, its maximum value is
It is often proportional to the magnitude of the tightening torque of the tightening member at the time of completion of the tightening, and the maximum value is such that the first measured tightening torque (estimated tightening torque _Th ) is the largest. it focuses on the fact that often, from a change of the estimated tightening torque T _h to an arbitrary rotational speed from the starting seeking maximum torque, by setting the fault determination torque T ₂ in accordance with the maximum torque, above I noticed that the problem could be solved.

In order to realize such a solution, the inventors of the present application examined the number of times required to complete the tightening of all the tightening members to be tightened, and found the most necessary rotational speed among them. member of the rotation speed less, and judgment rotation speed, determine the maximum torque in the estimated tightening torque T _h up when rotating the judgment rotation speed from the starting, by adding a small value to the maximum torque value the proposes means according to claim 6, defect determination torque T _2.

(Trouble determination torque T in this embodiment)
_{As for} the configuration of the impact tightening tool for realizing the means, as shown in FIG. 12, the torque estimating unit 8 and the tightening unit are different from the configuration of the conventional impact tightening tool shown in FIG. This is provided with an automatic failure determination torque setting unit 15 connected to the attachment determination unit 9. Then, its operation be as fastening determination processing shown in FIG. 13, first, when the rotation angle phi _n between blow from the torque estimating unit 8 is input (step C1), (16) below based on, it consists has been started to determine the total rotation number [psi _all of the output shaft 5 to date (step F1).

(Equation 16)

Next, with reference to also Fig. 14 showing a transition such as the estimated tightening torque T _h for striking number theta _n, Continuing with the operation of the automatic setting unit 15, the total number of revolutions [psi _all the determination rotation It is determined whether the number is equal to or more than several ψ _h (step F).
2), if the does not exceed the rotational speed [psi _h, it a maximum torque in the estimated tightening torque T _h calculated by, any minute torque T _g values defect determination torque T plus while the ₂ (step F3), if it exceeds the determined rotation speed [psi _h is the maximum torque T _m1 in the estimated tightening torque T _h in up to [psi _h rotation after starting, any minute torque T _g the value obtained by adding the adapted and malfunction determination torque T ₂ (step F4).

In this manner, even when a member having a small tightening torque at the time of completion of tightening and a member having a large tightening torque are mixed and a tightening operation is performed, the members are adjusted to the respective members. Because there is no need to set the failure judgment torque,
Work efficiency can be improved. Note that to add a minute torque T _g to a maximum torque T _m1, if not added the torque, there is a possibility that more than easily malfunction determination torque T _2. Further, the processes after steps F3 and F4 are performed in steps C2 to C2 of FIG. 9 used in the third embodiment.
The processing is the same as that of C7, and the other configurations and operations are also the same as those of the above-described embodiments.

[Sixth Embodiment] (Basic Thought in This Embodiment) In the fifth embodiment, the present inventors set the judgment rotational speed 回 転_h from the start.
Determine the maximum torque T _m1 in up when rotated, and the value obtained by adding a predetermined value T _g to the maximum torque T _m1, With defect determination torque T _2, the tightening torque at the time of completion of tightening Even when a small member and a large member are mixed and a fastening operation is performed, an appropriate fastening state has been successfully obtained.

[0070] However, the estimated tightening torque T _h immediately after startup, or a too small by some disturbance, or when was excessive reverse, in accordance with the magnitude of the torque with the estimated tightening, defect determination since the torque T ₂ will be set too small or too large, without reaching complete clamping points, or worse stop tightening, there is a possibility that operation tightening from being continued. Therefore, the inventors of the present application
To solve these problems, as failure determination torque T ₂ does not become too small or too large, it is proposed to provide a predetermined upper and lower limits.

(Trouble determination torque T in this embodiment)
More specifically for the _second setting), and were as tightening determination processing shown in FIG. 15, when the rotation angle phi _n between blow from the torque estimating unit 8 is input (step C1), since the start obtains the total number of revolutions [psi _all of the output shaft 5 to date (step F1), the total number of revolutions [psi _all it is determined whether or not a determination rotation speed [psi _h or more (step F2). The defect determination torque automatic setting unit 15 of the present embodiment, when it does not exceed the determined rotation speed [psi _h is a defect determination torque T _2, the initial setting is kept torque T _d, the determination torque T ₂ Is not changed (step G1).

[0072] Next, if it exceeds the determined rotation speed [psi _h, with reference FIG. 16 (a) also showing changes in such estimated tightening torque T _h for striking number theta _n, of the automatic setting unit 15 continuing with the description of the operation, the maximum torque T _m1 in the estimated tightening torque T _h in up to [psi _h rotation after start, the temporary set value of the failure determination torque T ₂ values plus any minute torque T _g and T _2P (step F4a), its temporary set value T _2P,
If the torque is equal to or greater than the initial set torque _Td (step G2),
It is determined that the determination value is too large, the initial setting torque T _d and fault determination torque T ₂ (step G3).

On the other hand, as shown in FIG. 16B, in step G2, the provisional set value T _2P is changed to the initial set torque T _d.
, And the and in the case of permissible below the lower limit torque T _L which is pre-determined arbitrarily below (step G4), it is determined that the determination value is too small, the defect determination torque T ₂ the minimum allowable torque T _L ( Step G5). By the way, Step G
In 4, when the provisional set value T _2P is equal to or more than the allowable lower limit torque _TL , the determination value is determined to be an appropriate value, and the provisional set value T _2P is set as the failure determination torque T _2. (Step G6).

[0074] By doing so, the estimated tightening torque T _h immediately after startup, or a too small by some disturbance, or even if a too large at the opposite, the completion point with proper of fastening There is no danger that the fastening will be stopped without reaching, or the fastening operation will be continued, and an optimum fastening state can be obtained. Steps G1 and G
The processes after G5 and G6 are the same as the processes of steps C2 to C7 in FIG. 9 used in the third embodiment, and the other configurations and operations are the same as those of the above-described embodiments. No particular description is given here.

[Seventh Embodiment] (Basic Idea in This Embodiment) In the fifth and sixth embodiments described above, the inventors of the present invention set the determination rotational speed ψ _h
Even when the tightening work is performed by mixing a member with a small tightening torque and a member with a large tightening torque at the time of completion of the tightening, an appropriate tightening state can be successfully obtained. It has been noticed that the adoption of several ψ _h has another effect different from the effect intended by the inventors of the present application. While it is without using the adopted failure determination torque T ₂ in the third embodiment, which does not reach to the rotational speed,
Appropriate tightening can be obtained by using the means described in claim 8 in which the tightening is continued even when the torque fluctuation rate _Tv or the like becomes zero.

(Tightening Judgment in Impact Tightening Tool of this Embodiment) More specifically, it is the same as the tightening judging process shown in FIG. 17, and is different from the flowchart of FIG. 9 showing the third embodiment. , instead of steps E1 and E2, employs a step H the total number of revolutions [psi _all it is determined whether or not exceeds the determination rotation speed [psi _h, depending on whether exceeds the rotation speed [psi _h, the central axis of the bolt and the nut It is determined whether or not an assembly defect has occurred due to a displacement or the like.

[0077] More particularly, with reference to also Fig. 18 showing the transition of such estimated tightening torque T _h for striking number theta _n, when the operation of the present embodiment, the torque variation ratio T _v is 0
Θ ₁ , which determines that the tightening of the resin-based member has been completed,
in terms of theta ₂ (step C6), the total number of revolutions [psi _all sees whether exceeds the determination rotation speed [psi _h, since both the point does not exceed the rotational speed [psi _h (Step H), is some trouble When it is determined that the occurrence has occurred, the fastening is continued, and the fastening determination process is terminated.

On the other hand, in terms of θ _{r at} which the torque fluctuation rate T _v becomes 0 or less and θ _m at which it is determined that the tightening of the metal member having the torque fluctuation amount T _q of 0 or less is completed, the total Looking at whether the rotation speed ψ _all has exceeded the judgment rotation speed ψ _h ,
Since exceeds the rotation speed [psi _h both points (Step H), without bug occurs, it is judged that the fastening member is fastened to the suitability (seated), the shut-off process This is performed (step C7).

FIG. 18 used in the description of this embodiment
Shows an example of a tightening of metallic member, the estimated tightening torque T _h at completion point theta _r tightening resin member, since a member determination torque above T ₁ (step D2), is determined that tightening the metallic member, the control proceeds to variation mode (step D3), when it is complete clamping points theta _m of metallic member (step D4), so as to perform shut-off process (Step C7) is as described in the second embodiment.

[0080] Thus, at the time it is determined that the completed tightening, when the total number of revolutions [psi _all it is determined whether it exceeds a threshold rotational number [psi _h, exceeding the determined rotation speed [psi _h, By shutting off, it is possible to perform optimal tightening even if there is a slight defect in assembly. Note that other configurations and operations are the same as those of the third embodiment, and therefore will not be particularly described here.

[0081] [Eighth Embodiment] (basic idea in the present embodiment) the present inventors have found that in the seventh embodiment of the above, by employing the determined rotation speed [psi _h, some assembling Even if there is a defect, another effect that optimum tightening can be performed was found.However, since the determined rotation speed 不_h is unchanged, tightening is performed at a rotation speed smaller than the determined rotation speed ψ _h . When the tightening member is out of the design range in which the tightening is completed, the tightening operation may be continued even though the tightening is completed.

On the other hand, in the case where a member having an extremely small number of times required for fastening and a member having an extremely large number of times required for fastening are mixed and fastened, the fastening operation is continued as described above. In order to prevent this, the judgment rotation speed ψ _h is set according to the member whose number of times required until tightening is extremely small,
Then, when viewed from the rotational speed of the required number is very large member to fastening, for determining the rotation speed [psi _h is the number of revolutions very small, due to slight defects in assembling between both rotational speed when there is a rise in the estimated tightening torque T _h is,
Even though the tightening has not been completed, the tightening operation may be stopped. Accordingly, the inventors of the present application is to solve the above problems, proposes a means according to claim 10 capable of changing the determination rotation speed [psi _h.

(Structure of Impact Tightening Tool of the Present Embodiment) A specific structure of the impact tightening tool for that purpose is as follows.
It is as shown in Figure 19, the configuration of a conventional impact fastening tool shown in FIG. 1, is connected to the tightening judging unit 9, determining rotation speed setting that can change the determination rotation speed [psi _h The device 14b is provided. The judgment rotation speed setting unit 14b may be in the same manner as the defect determination torque setter 14a shown in the fourth embodiment, for example, using a variable resistor or the like, so that it can be set freely determined rotation speed [psi _h Good.

As described above, by providing the setting device 14b, the operator can determine the determined rotation speed in the work site according to the target fastening member having a low rotation speed or the member having a high rotation speed. ψ Since _h can be set, the above-described non-stop or halfway stop can be avoided, and an optimum tightening state can be obtained. Note that other configurations and operations are the same as those of the above-described embodiments, and therefore will not be particularly described here.

[Ninth Embodiment] (Basic Concept in This Embodiment) In each of the above-described embodiments, the inventors of the present invention use all kinds of fastening members, or have some inconvenience in assembly. Even though, it was possible to provide a tightening tool that can perform optimal tightening without damaging the tightening member, but the inventors of the present application do not stop there. It is thought that it may be possible to deal with the case where a previously tightened member is incorrectly tightened.If the already tightened member is tightened, the estimated tightening is performed from the beginning. Torque _Th
I thought that it would take advantage of the fact that the value of appeared as a large value.

In order to utilize such a phenomenon, the inventors of the present application focused again on the fact that the maximum tightening torque T _max differs among members, and examined the maximum tightening torque T _max of various resin-based members. Te, by the smallest torque from among a plurality of maximum tightening torque T _max in the resin member, increase the tightening determined torque, whether the torque T _h with estimated tightening exceeds the Retighten determination torque, already tightening A means according to claim 11 for judging whether or not the fastening member attached is erroneously tightened is proposed.

(Redetermination of Additional Tightening in Impact Tightening Tool of this Embodiment) More specifically, this is the same as the tightening determination process shown in FIG. 20, and FIG. 9 shows the third embodiment.
Than in step C5 in the flow chart of when the torque variation ratio T _v is determined not to exceed the judgment start reference value A, that is, when NO, the tightening determination torque T ₃ torque T _h with estimated tightening increases step J is provided of determining whether, in the step J, when increased is determined whether it exceeds the tightening determination torque T _3, exceeds the determination torque T ₃ is designed so as to shut off ( Step C7).

[0088] More particularly, with reference also to FIG. 21 showing the transition of such estimated tightening torque T _h for striking number theta _n, when the operation of the present embodiment, the torque fluctuation rate when tightening is performed increases T Changes such as _v are extremely small and do not exceed the determination start reference value A (step C5). However, even in this case, as shown in theta ₂ in FIG. 10, simply because it may only not exceed the determination start reference value A, the tightening determination torque T ₃ increases the estimated tightening torque T _h beyond that if it is judged whether, as shown in FIG. 21, if it exceeds the determination torque T ₃ performs (step J), increased shut-off as a fastening has been performed (step C7).

[0089] On the other hand, if it does not exceed the determination torque T ₃ (step J), as ₂ theta in Figure 10 described above, increasing rather than being tighten, proper working tightening line As a result, the tightening operation is continued. Thus, without torque variation ratio T _v etc. exceeds the determination start reference value A, and, when the torque T _h with estimated tightening exceeds the tightening determination torque T ₃ increases, and determines that the tightening has occurred By shutting off, unnecessary work is not performed, and the energy consumed by retightening can be reduced.

Note that the judgment start reference value A in this embodiment is
Is determined so that the torque fluctuation rate T _{v and the} like do not exceed the reference value A when retightening is performed. Further, in the present embodiment, since the description has been made based on the third embodiment, the smallest torque among the plurality of maximum tightening torques T _max in the resin-based member is set as the additional tightening determination torque. In the case where only the metal-based member is to be tightened, it is needless to say that the smallest torque among the plurality of maximum tightening torques _{Tmax for} the metal-based member is adopted.

[Tenth embodiment] (Basic concept in this embodiment) In the ninth embodiment, the inventors of the present invention provide an impact tightening tool which does not needlessly perform an operation. Although it was possible, in order to further improve the work efficiency, in each of the above embodiments, if the operation is stopped halfway due to an erroneous determination, it is necessary for the worker to pull the trigger again to continue the tightening work, We paid attention to being troublesome. In order to improve such a situation, the inventors of the present application have proposed a means according to claim 12, which controls the rotation of the impact tightening tool again when a predetermined time has elapsed without releasing the trigger. is suggesting.

(Regular processing in the impact tightening tool according to the present embodiment) More specifically, it is the same as the tightening determination processing shown in FIG. 22, and corresponds to the step in the flowchart of FIG. 2 showing the first embodiment. After A5 has been processed,
Timer measurement is started (step I1), the trigger is not released (step A6), and when a predetermined time _Tm has elapsed (step I2), the rotation control of the motor 1 is performed again (step I2). A2). By doing so, in each of the above-described embodiments, even when the vehicle is stopped halfway due to an erroneous determination, the rotation control is automatically started when the predetermined time _Tm has elapsed. There is no need to redraw, and workability can be improved.

[Regarding Supplementary Items in Each Embodiment] In each of the above embodiments, the impact fastening tool has been described. However, the inventors of the present application are limited to the fastening tool of this type. It can be widely used for general tightening tools, and uses a frequency generator as the rotation speed detection means and counts pulse edges to substitute for the rotation angle detection means. It is pointed out that the present invention is not limited to this, but may be replaced by an encoder or a potentiometer. still,
In general, the rotation speed is obtained by an encoder or the like by taking a difference.

[0094] Further, as described in the first embodiment, the inventors have found that the torque variation ratio T _q and the torque variation ratio T _v, although determined by the difference of moving averages,
This is because noise was taken into account, and the difference between the current value and the previous value may be simply taken, and not only the differential value based on the rotation angle θ but also the differential value based on time may be used. ing. That is, more specifically, the claims of the inventors of the present application show that the torque fluctuation amount _Tq is, as shown in Expression (17), the change in the tightening torque T with respect to the change in the rotation angle θ or the time t. It means the ratio.

[Equation 17]

On the other hand, the torque fluctuation rate T _v means the ratio of the change in the torque fluctuation T _{q to} the change in the rotation angle θ or the time t, as shown in the equation (18).

(Equation 18)

Further, in each of the above-described embodiments, the inventors of the present invention tighten when the torque fluctuation amount T _q and the torque fluctuation rate T _v exceed a predetermined threshold value and become 0 or less. However, it is asserted that the tightening may be determined when the torque becomes equal to or less than a predetermined threshold, and that the torque fluctuation amount _Tq or the like does not exceed the predetermined threshold. ,
Or a method of obtaining the sum of the torque fluctuation amounts _{Tq and the} like while the torque fluctuation amounts _{Tq and the} like have a positive value together with the conditions, and determining a point in time when the sum exceeds a threshold value as a fastening completion point. But he points out.

【The invention's effect】

As described above, according to the first aspect of the present invention, after the torque fluctuation rate exceeds the determination start reference value, the torque fluctuation rate becomes approximately 0%.
When the following conditions are met, it is determined that the tightening of the screws and the like has been completed, and the motor is stopped, so that appropriate tightening is performed without breaking brittle materials such as resin members by tightening. It has the effect of being able to do so.

Next, according to the second aspect of the present invention, when the torque fluctuation rate becomes about 0 or less after exceeding the judgment start reference value, it is determined whether the tightening torque exceeds the member judgment torque. Judgment, if it does not exceed the member determination torque, it is determined that the tightening of the resin-based member has been completed, while if it exceeds the member determination torque, the rotation control of the motor is continued, When the amount of fluctuation falls below about 0,
Since the motor is stopped when it is determined that the tightening of the metal member has been completed, no matter what kind of tightening member is used, the tightening member is not damaged, and the optimum tightening state is obtained. Is obtained.

Next, according to the third aspect of the present invention, when it is determined that the tightening is completed, it is determined whether the tightening torque exceeds the malfunction determination torque, and the tightening torque does not exceed the malfunction determination torque. In this case, it is determined that a failure or the like has occurred, and the rotation control of the motor is continued.On the other hand, if the failure determination torque has been exceeded, it is determined that the screw or the like is properly tightened. Since the motor is stopped, there is an effect that optimal tightening can be performed even if there is a defect in assembly.

Similarly, in the invention according to claim 4, when the torque fluctuation amount exceeds the judgment start reference value and becomes about 0 or less, it is determined whether the tightening torque exceeds the malfunction judgment torque. If the torque does not exceed the malfunction determination torque, it is determined that a malfunction or the like has occurred, and rotation control of the motor is continued. Is determined to be properly tightened and the motor is stopped, so even if there is a failure in assembling the metal-based member, it is possible to perform optimal tightening. Play.

Further, in the invention according to claim 5,
Since a failure determination torque setting device capable of freely changing the failure determination torque is provided, the worker can set the failure determination torque at the work site according to the target fragile fastening member or robust member. Can do
It is possible to prevent the motor from stopping or stopping halfway, and to obtain an optimum tightening state.

Further, in the invention according to claim 6,
Judge whether the total rotation speed of the motor exceeds the judgment rotation speed, and if it does not exceed the judgment rotation speed, find the maximum torque among the tightening torques from the start to the present, and slightly While the malfunction determination torque is set to be large, if the rotation speed exceeds the determination rotation speed, the maximum torque is obtained from the tightening torque from the start to the determination rotation speed, and is slightly larger than the maximum torque. Since the malfunction determination torque is set so that the tightening work is performed by mixing a member having a small tightening torque at the time of completion of tightening and a member having a large tightening torque. Since there is no need to set the failure determination torque according to the member, there is an effect that the working efficiency can be improved.

Further, in the invention according to claim 7,
It is determined whether or not the total rotation speed of the motor exceeds the determination rotation speed.If the total rotation speed does not exceed the determination rotation speed, the malfunction determination torque is set to the initial setting torque. Determine the maximum torque among the tightening torques from the start to the determination rotation speed, determine the temporary set value so as to be slightly larger than the maximum torque, and determine whether the temporary set value is equal to or greater than the initial set torque. If the torque is equal to or more than the initial set torque, the malfunction determination torque is set to the initial set torque, while if the torque is smaller than the initial set torque, the temporary set value is equal to or less than an arbitrarily determined allowable lower limit torque. It is determined that when the torque is equal to or smaller than the allowable lower limit torque, the malfunction determination torque is set to the allowable lower limit torque, and when the torque is larger than the allowable lower limit torque, the temporary setting value is set. Even if the tightening torque immediately after start-up is too small due to some disturbance or vice versa, the tightening may stop without reaching the appropriate tightening completion point, There is an effect that an optimum tightening state can be obtained without a fear that the tightening operation is continued.

Further, according to the present invention, when it is determined that the tightening is completed, it is determined whether or not the total rotation speed of the motor exceeds the determination rotation speed. If not, it is determined that a failure in assembly has occurred, and the rotation control of the motor is continued, while if the rotation speed exceeds the determination rotation speed, it is determined that the screws and the like are properly tightened. Since the motor is stopped after the judgment, the same effect as in the invention described in claim 3 can be obtained, even if there is a problem in assembly, that optimum tightening can be performed.

Similarly, according to the ninth aspect of the present invention, when the amount of torque fluctuation becomes about 0 or less after exceeding the determination start reference value, the total number of rotations of the motor becomes less than the determination rotation number. Judgment whether it exceeds, and if it does not exceed the judgment number of revolutions, it is judged that an assembly defect etc. has occurred,
If the rotation speed of the motor is exceeded while the rotation control of the motor is continued, it is determined that screws or the like are properly tightened, and the motor is stopped.
In the same manner as the invention described in (1), even if there is a failure in assembling the metal-based member, it is possible to perform an optimum tightening.

Further, according to the tenth aspect of the present invention, since the judgment speed setting device capable of freely changing the judgment speed is provided, the operator can set the target speed at the work site. Since the determination rotation speed can be set according to each of the fastening members having a small number of rotations or the members having a high rotation speed, the above-described non-stop or halfway stop can be avoided, and the optimum tightening state can be obtained. It has the effect of being able to do it.

According to the eleventh aspect, when the torque variation or the torque variation does not exceed the determination start reference value, it is determined whether the tightening torque exceeds the tightening determination torque. If the torque does not exceed the retightening determination torque, it is determined that the screws and the like are properly tightened, and the rotation control of the motor is continued. Since it is determined that the motor is tightened and the motor is stopped, it is possible to avoid unnecessary work and to reduce the energy consumed by the additional tightening.

Finally, according to the twelfth aspect of the present invention, when the motor control unit starts counting time from when a stop command is received from the tightening determination unit, and the trigger operated by the operator is pulled. Therefore, the motor is started again when a predetermined time elapses arbitrarily determined. Therefore, in the invention described in each of the above claims, even if the motor is stopped halfway due to an erroneous determination. Since the rotation control is automatically started after the elapse of the predetermined time, the operator does not need to re-trigger the state, and the operability can be improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an impact tightening tool in the present application.

FIG. 2 is a flowchart showing a normal process of the impact tightening tool.

FIG. 3 is a flowchart illustrating a process of detecting an impact of the impact tightening tool in the present application.

FIG. 4 is a diagram showing a relationship between a rotation angle θ and a tightening torque T;

FIG. 5 is a flowchart illustrating a tightening determination process of the impact tightening tool according to the first embodiment.

[6] A diagram showing the response of the impact fastening tool in the first embodiment, shown striking number θ torque with the estimated tightening against _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v ing.

FIG. 7 is a flowchart illustrating a tightening determination process of an impact tightening tool according to the second embodiment.

[8] a view showing a response of a tool with an impact fastening in the second embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v (A) is a diagram when a resin-based member is tightened, and (b) is a diagram when a metal-based member is tightened.

FIG. 9 is a flowchart illustrating a tightening determination process of the impact tightening tool according to the third embodiment.

[Figure 10] A graph showing the response of the impact fastening tool in the third embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v (A) is a diagram when a resin-based member is tightened, and (b) is a diagram when a metal-based member is tightened.

FIG. 11 is a configuration diagram of an impact fastening tool according to a fourth embodiment.

FIG. 12 is a configuration diagram of an impact fastening tool according to a fifth embodiment.

FIG. 13 is a flowchart showing a tightening determination process of an impact tightening tool according to the fifth embodiment.

[Figure 14] A graph showing the response of the impact fastening tool in the fifth embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v Is shown.

FIG. 15 is a flowchart illustrating a tightening determination process of an impact tightening tool according to the sixth embodiment.

[Figure 16] A graph showing the response of the tool with impact fastening in the sixth embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v shows a diagram of (a) the figure when the provisional setpoint T _2P is equal to or greater than the initial setting torque T _d, (b) if the provisional setpoint T _2P is equal to or less than the allowable minimum torque T _L.

FIG. 17 is a flowchart illustrating a tightening determination process of the impact tightening tool according to the seventh embodiment.

[Figure 18] A graph showing the response of the tool with impact fastening in the seventh embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v Is shown.

FIG. 19 is a configuration diagram of an impact fastening tool according to an eighth embodiment.

FIG. 20 is a flowchart illustrating a tightening determination process of an impact tightening tool according to the ninth embodiment.

[Figure 21] A graph showing the response of the impact fastening tool in the ninth embodiment, the torque with the estimated tightening against the striking number theta _n T _h, the amount of torque fluctuation T _q, the transition of the torque variation ratio T _v Is shown.

FIG. 22 is a flowchart showing a normal process of the impact fastening tool according to the tenth embodiment.

FIG. 23 is a configuration diagram of an impact fastening tool according to a conventional embodiment.

[24] against the striking number theta _n in fastening operation is a diagram illustrating a change in the torque T and the torque variation T _q tightening.

FIG. 25 is a diagram showing a conventional tightening determination process, and shows a tightening torque T and a torque fluctuation amount T with respect to a rotation angle θ.
_This shows the change in _q .

FIG. 26 is a diagram illustrating a case where the resin-based member is tightened using the conventional tightening determination process, and it is determined that the tightening has been completed when the torque variation _Tq has become 0;

FIG. 27: The screw grooves are irregular, the member sandwiched between the bolt and the nut is slightly curved, the center axis of the bolt and the nut is displaced, dust is entangled, and the surface of the screw hole is removed. FIG. 3 is a diagram showing a case where the tightening torque T temporarily increases due to scraping off of a baking coating or the like.

[Explanation of symbols]

1 Motor 8 Torque Estimating Unit (Torque Estimating Means) 9 Tightening Judgment Unit (Tightening Judging Means) 10 Motor Control Unit (Motor Control Means) 14a Fault Judgment Torque Setting Unit (Judgment Torque Setting Unit) 14b Judgment Rotation Speed Setting Unit a determination start reference value t time T tightening torque T ₂ defect determination torque T _2P defect provisional setting value T ₃ Retighten determined in decision torque T ₂ torque T _d initialization torque T with _h estimated tightening torque T _L allowable minimum torque T Maximum tightening torque T from the _m1 start to the judgment rotation speed ψ _{h Tq} Torque fluctuation amount T _v Torque fluctuation rate θ Motor rotation angle θ _n Impact speed ψ _all Total rotation speed ψ _h Judgment rotation speed

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Miyazaki 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor In-house F term (reference) 3C038 AA01 BC04 CA06 CB02 CC03 EA06

Claims (12)

[Claims] 1. A motor control means for controlling rotation and stop of a motor, and a torque estimating means for estimating a tightening torque of an output shaft of the motor. A tightening tool for performing a tightening operation of a bolt or the like, wherein a torque fluctuation amount which is a ratio of a change in the tightening torque to a change in a rotation angle or time of the motor is obtained, and a change in the rotation angle or time of the motor is obtained. The torque fluctuation rate, which is the rate of change of the torque fluctuation amount with respect to, is determined. When the torque fluctuation rate becomes about 0 or less after exceeding an arbitrarily determined judgment start reference value, tightening of the screw or the like is performed. A fastening tool that determines that the control is completed and outputs a stop command to the motor control means. A motor control means for controlling rotation and stop of the motor; and a torque estimating means for estimating a tightening torque of an output shaft of the motor. A tightening tool for performing a tightening operation of a screw or a bolt made of a member or a metal-based member or the like, wherein a torque variation amount which is a ratio of a change in the tightening torque to a change in a rotation angle or time of the motor is obtained. Determine the torque fluctuation rate, which is the rate of change of the torque fluctuation amount with respect to the change in the rotation angle or time of the motor, and the torque fluctuation rate is
When the value becomes approximately 0 or less after exceeding an arbitrarily determined judgment start reference value, the tightening torque is a boundary value between the maximum tightening torque of the resin-based member and the maximum tightening torque of the metal-based member. It is determined whether the torque exceeds the member determination torque. If the torque does not exceed the member determination torque, it is determined that the tightening of the resin-based member has been completed, and a stop command is output to the motor control means. If the determination torque is exceeded, the output of the rotation command to the motor control means is continued, and when the torque fluctuation amount becomes about 0 or less, it is determined that the tightening of the metal member has been completed. And a tightening determining means for outputting a stop command to the motor control means. 3. When it is determined that the tightening is completed,
It is determined whether the tightening torque exceeds a fault determination torque that is set slightly larger than the maximum torque when the tightening torque temporarily increases due to an assembly fault or the like. If the torque is not exceeded, it is determined that the failure or the like has occurred, and the rotation command is continuously output to the motor control means. 3. The tightening tool according to claim 1, further comprising a tightening determining unit that determines that the is tightened properly and outputs a stop command to the motor control unit. 4. A motor control means for controlling rotation and stop of the motor, and a torque estimating means for estimating a tightening torque of an output shaft of the motor. A tightening tool for performing a tightening operation such as a bolt, wherein a torque fluctuation amount which is a ratio of a change in the tightening torque to a change in the rotation angle or time of the motor is obtained, and the torque fluctuation amount is arbitrarily determined. When the value becomes about 0 or less after exceeding the determination start reference value, the tightening torque is
When the tightening torque temporarily increases due to an assembly failure, etc., it is determined whether the torque exceeds a set failure determination torque slightly larger than the maximum torque, and if the failure determination torque is not exceeded It is determined that the failure or the like has occurred, and the rotation command is continuously output to the motor control means.If the failure determination torque is exceeded, the screw or the like is properly tightened. A tightening determination unit that determines that the motor control unit has stopped and outputs a stop command to the motor control unit. 5. The tightening tool according to claim 3, further comprising a trouble determining torque setting means capable of freely changing the trouble determining torque of the tightening determining means. 6. A determination is made as to whether or not the total number of rotations of the motor exceeds a minimum required number of rotations, that is, a determination number of rotations required for completing tightening of all members to be tightened such as the screws. If the rotation speed is not exceeded,
When the maximum torque is obtained from the tightening torque from the start to the present and the malfunction determination torque of the tightening determination means is set so as to be slightly larger than the maximum torque, while the rotation speed exceeds the determination rotation speed. In the meantime, the maximum torque is obtained from the tightening torque from the start to the determination rotation speed, and the failure determination torque of the tightening determination means is set so as to be slightly larger than the maximum torque. 5. The tightening tool according to claim 3, further comprising means. 7. A determination is made as to whether or not the total number of rotations of the motor exceeds a minimum required number of rotations, ie, a determination number of rotations required for completion of tightening of all members to be tightened such as the screws. If the rotation speed is not exceeded,
While the failure determination torque of the tightening determination means is set to an arbitrarily set initial torque, while exceeding the determination rotation speed, the maximum torque among the tightening torques from start to the determination rotation speed is set. Is determined, and a temporary set value is determined so as to be slightly larger than the maximum torque, and it is determined whether the temporary set value is equal to or more than the initial set torque,
When the torque is equal to or more than the initial set torque, the malfunction determination torque of the tightening determination unit is set to the initial set torque, and when the torque is smaller than the initial set torque, the temporary set value is set to an allowable lower limit torque that is arbitrarily determined. If the torque is equal to or less than the allowable lower limit torque, the malfunction determination torque of the tightening determination unit is set to the allowable lower limit torque, and if the torque is larger than the allowable lower limit torque, the temporary setting value is set. The tightening tool according to claim 3 or 4, further comprising means for automatically setting a failure determination torque. 8. When it is determined that the tightening has been completed,
It is determined whether the total number of rotations of the motor exceeds the minimum required number of rotations, which is the minimum required number of rotations, in the number of times required for the tightening of all the members to be tightened such as the screw to be completed. If it does not exceed the number, it is determined that a malfunction in assembly or the like has occurred, and the output of the rotation command to the motor control means is continued. 3. A tightening judging means for judging that a screw or the like is properly tightened and outputting a stop command to the motor control means.
The described tightening tool. 9. A tightening tool comprising a motor control means for controlling rotation and stop of a motor, and performing a tightening operation of a screw, a bolt, or the like using a rotational force of the motor. A torque fluctuation amount, which is a ratio of a change in the tightening torque to a change in the rotation angle or time, is determined. After the torque fluctuation amount exceeds an arbitrarily determined judgment start reference value, about 0%.
When the following, when the total number of rotations of the motor exceeds the minimum required number of rotations, which is the minimum required number of rotations, in the number of times required to complete the tightening of all the members to be tightened such as the screws. If the rotation speed does not exceed the determined rotation speed, it is determined that a failure in assembly or the like has occurred, and the output of the rotation command to the motor control means is continued. A tightening tool comprising: a tightening determining unit that determines that the screw or the like is properly tightened when it exceeds the limit and outputs a stop command to the motor control unit. 10. The tightening tool according to claim 8, further comprising a judgment speed setting device capable of freely changing the judgment speed of the tightening judgment means. 11. When the torque fluctuation amount or the torque fluctuation rate does not exceed the determination start reference value, the tightening torque is set to the maximum tightening torque of all the tightening target members such as the screws. It is determined whether the torque exceeds the additional tightening determination torque set to the smallest tightening torque.If the torque does not exceed the additional tightening determination torque, it is determined that the screw or the like is properly tightened. While the output of the rotation command is continued to the motor control means, if the torque exceeds the additional tightening determination torque, it is determined that the additional tightening has been performed, and the stop command for outputting a stop command to the motor control means is output. The fastening tool according to any one of claims 1 to 10, further comprising attachment determination means. 12. The motor control means starts time counting from a time when a stop command is received from the fastening determination means, and waits for a predetermined time arbitrarily determined in a state where a trigger operated by an operator is pulled. The tightening tool according to any one of claims 1 to 11, wherein the motor is restarted when the operation is performed.