JPS5890474A - Clamping method select type bolt clamping device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This analysis uses a digital arithmetic device and uses the torque method, rotation angle method, torque/rotation angle method, and axial force 11 theory.

This invention relates to a bolt tightening device that allows you to freely select one of several tightening methods, such as the load-bearing point method and the load-control washer.

Torque method has traditionally been used as a method for tightening bolts or nuts.
Rotation angle method, torque/rotation angle method, axial force control method, load-bearing point method,
Various methods are known, including tightening methods using load control washers. The torque/rotation angle method detects the torque or torque change rate within the elastic range of the bolt, and starting from the tightening position where these values reach a predetermined value, the rotation angle θ is set in advance by 5 to correspond to the predetermined axial force of the bolt. The 0-rotation angle method, which is used to tighten bolts, starts from the state where there is no gap between the bolts to be fastened, and then tightens at a predetermined rotation angle to correspond to the predetermined axial force of the bolt. Tightening is completed by tightening θ. In the torque method, tightening is completed by applying WI up to a predetermined tightening torque value corresponding to a predetermined axial force of the bolt. In addition, the axial force management method calculates the torque or rotation angle corresponding to the final target axial force from the relationship between the axial force, rotation angle, and tightening torque, and performs tightening.

The stress point method is based on the fact that the rate of increase in the tightening torque of the electric motor #i is calculated with respect to the rotation angle or tightening time, and this rate of increase becomes less than a predetermined value defined by VC, i4 after the elastic region. It is intended to stop.

In addition, there is a wide range of tightening methods using a load control washer that plastically deforms under a predetermined tightening load within the elastic range of the bolt.
6-47528 etc.). This method utilizes the fact that the tightening torque remains approximately constant during plastic deformation of the load control washer, and detects the end of the plastic deformation region of the washer from fluctuations in the rate of change of the tightening torque.

This is to stop tightening.

However, the rotation angle method has the drawback that the #4 difference in the starting point directly results in a tightening error, but on the other hand, the tightening force is strictly 1ltNA.
It has the advantage of being easy to tighten when it is not required. Furthermore, the torque method utilizes the proportional relationship between torque and axial force.

The rotation angle method has the advantage of being able to check torque using a ratio torque wrench, but what about the variations in the constants? Since it is ignored, it has the disadvantage that the axial force varies. Furthermore, the axial force management method considers different coefficients of friction for each bolt, so the axial force of each bolt can be accurately matched to the target axial force, allowing for accurate tightening. Since the device was composed of analog circuits, it was difficult to input and maintain various constants determined by the bolt's nominal diameter, material, etc., and the aim was to improve accuracy.

In addition, the stress point method and the method using a load control washer have a problem in that malfunctions may occur when the rate of change in torque varies minutely depending on the condition of the friction surface.

As described above, each tightening method has its own advantages and disadvantages, so it is necessary to use each tightening method properly depending on the required tightening accuracy of the bolt.

However, conventional bolt tightening devices only use a single tightening method 1c.
Since the belt is made to be compatible with various tightening methods, there is a disadvantage that it is necessary to prepare a separate tightening device for different tightening methods.

This invention is considered to be #i in view of these inconveniences, and allows free use of the torque method, rotation angle method, torque/rotation angle method, axial force management method, load-bearing point method, and tightening method using the Urarashi control washer. It is an object of the present invention to provide a Bordeaux tightening device that can be selected and that can adopt an optimal tightening method according to the tightening conditions. For those that detect the tightening torque and tightening rotation angle as digital signals, the torque method, rotation method,
A memory that stores calculation programs for each of the torque/rotation angle method, axial force IGTM method, load-bearing point method, and tightening method using a control washer, and a selection to select any calculation program stored in this memory. It is equipped with a switch and a digital calculation device that performs calculations according to the calculation program of the tightening method selected by the selection switch and outputs a tightening stop signal, thereby making it possible to select the tightening method.

The present invention will be described in detail below based on the illustrated example.

FIG. 1 is a block diagram showing a first embodiment of a bolt tightening device according to the present invention. In Figure 51!1, the symbol l is an AC power supply, and the power of this tllill is supplied to the switches 2, semiconductor switches 3, . +iil [supplied to a closed circuit consisting of a winding motor 4. Reference numeral 5 denotes a rotation angle detector which outputs an angle pulse P (Δ#) every tightening rotation angle Δ# of bolts and nuts as the electric motor rotates 40 times.

Reference numeral 6 denotes a torque detector, and this torque detector 6 is equipped with a strain gauge attached to a part of the electric motor 4 that receives the tightening reaction force, and converts the strain caused by the tightening reaction force into electric No. 41. Detects applied torque. 7 is an AD converter that converts the electrical signal indicating this tightening torque into a digital signal T. 8 is a digital arithmetic device, and this arithmetic device 8
performs predetermined calculations sequentially according to a flowchart described later.

9 is a memory that stores an arithmetic program for this arithmetic unit 8 to perform a predetermined arithmetic operation, and 10 is a threshold value 7t.
Input/output for setting various setting values such as the data to be used (h, Pol), and the inertia rate of the rotating part of the tightening device *
d, 11 is a phase control circuit, and 12 is a gate pulse generation circuit.The 1-phase control circuit 11 generates a gate pulse GikN based on the tightening stop signal S generated by the arithmetic unit 8. , and open the semiconductor switch 34 [and cut off the power to the electric machine 4]. 13 detects the opening of the switch 2 and operates the arithmetic unit 8.
This is a power supply voltage detector that outputs a computation start f-sign for . 14 is a selection switch. The memory 9 stores a torque method calculation program PRG (T), a rotation angle method program PRG (R), a torque/rotation angle method program)'
RG (TR), program for increasing axial force '# PRG (J)
, load-bearing point method program PRG (Y), load I [1111
#A program PRG (LC) for the tightening method using a washer is placed in advance, and the program Jl*It 8 is operated according to the program selected with the selection switch 14. , 2 is a flowchart showing the overall operation of this embodiment.

First, set the selection switch 14 to the required position - to select the tightening method 9. Next, close the switch 2 and the power supply voltage detection 61
3 detects the opening of this switch 2 and sends a calculation start signal to the calculation device 8. First, Stella 7 must determine whether or not the selection switch 14 has selected the torque method.
If the torque method is selected, the torque method program PRG(T) is continuously retrieved from the memory 9 and calculations are performed.

Similarly, steps 102, 104. 106.10g
The selected tightening method is determined, and the calculation program corresponding to the selected tightening method is successively executed to perform calculations.

Below are the torque method, one rotation angle method, and the torque/rotation angle method.

Programs PRG (T), PRG (R) for the axial force management method, stress point method, and tightening method using #load washer,
PRG (TR), PRG (J), PRG (Y), PRG
(LC) is sequentially clarified using a flowchart.

<Torque method> FIG. 3 is a flowchart of the torque method, and FIG. 4 is a diagram of its tightening characteristics. When the selection switch 14 selects the torque method, the arithmetic unit 8 executes the program PRG(T
), a pre-work start signal is sent to the 1-phase control circuit 11, and the gate pulse generation circuit 12 generates a phase-controlled gate pulse G. Therefore, the semiconductor switch 3 is fired in phase synchronized with the trigger pulse G, and the switch 1I
llI machine 41C body movement 1lttIL started flowing and electric motor 4
begins to rotate. As the bolt is tightened, the rotation angle detector 5 outputs an angle pulse P (80) at every predetermined rotation angle Δθ.The AD converter 7 detects the ever-changing tightening torque. Continue to output T as a digital signal.

Calculation *-8 is the threshold value TthIk:d set by the input/output device IO, while the digitalized tightening torque T
Read the Ik angle pulse P(80)% and compare the two (
Step 200), read the new tightening torque T and repeat this comparison operation until the tightening torque T exceeds the threshold value Tth.
In the elastic region A circle shown in the figure, the torque value is set to be slightly smaller than the final target delivery torque Ta. On the other hand, the calculation Mm@ includes black and pulse generation, and integrates the IM time t after the start of tightening. This is 4j until the condition of step 200 is satisfied! When the spacing t exceeds the setting I#I]t1, this is determined in step 20g, and a warning is issued as the bolt is rotating with the nut, and step 2o4) #1i attachment is stopped. . Also, the time t required for step 1000 condition formation':/ is set to t.
If it is 2 or less, it is 1, and this is determined in step 7b 206, and the screw thread deformation, etc.
: The tightening is stopped, or if the tightening has already been completed, an alarm is issued (Step 204). That is, steps 202, 204, 206
Since the time T required for the tightening torque T to reach the threshold value Tth is outside the range of tz < t < b, an abnormality is detected and an alarm is generated, while the benefit stop signal S is The abnormality detection step is sent to step #411 and the semiconductor switch 3 is opened to disconnect the power to the motor 4.

It has become a pool.

In this embodiment, in order to accurately tighten the pipe, the additional tightening amount due to inertia after the busy power supply is shut off is corrected.

For this reason, first of all, the original M4r-arm beak of this inertia correction is calculated. Now, if friction is omitted, the equation of motion when tightening is 4%. With the number of springs, E=
It is possible to set an approximate value in advance or use a value measured during 1144 years of age.

T is the torque of the electric motor, or t is the time, Jm of the power supply
After m, T becomes 岑, so at this time, holds true. This equation (2) is expressed as θ=θO, dθ/dt−ω at
If we solve it under the W-period equation of 0, we get. Here β2=
E/J, g+ = tan-” (jo//ωo). From this equation (3), the rotation angle θ after the power supply is turned off is
! #. Hato becomes.

On the other hand, the maximum tightening torque of the bolt is the maximum value θ of the rotation angle θ.
Since it is at m, it is as follows.

Tm = Eell Here, if the speed fluctuation rate of the motor before the electric power supply is small, the tightening torque T before the power supply is
Since o becomes To=FJOo, equation (5) becomes a modulus after all.

As is clear from this equation (6), the power distribution WRviIL
If the tightening torque To at the initial stage and the angular velocity ω0 at that time are known, it is possible to predict I & large tightening torques T-, -f, that is, the final tightening torque Te in consideration of the amount of additional tightening due to inertia. This Te is the final predicted tightening torque, and this tightening torque is used to quickly calculate @, and when this tightening torque Ts is the final -jlA tightening torque Ts K4, which is preset according to the type of bolt, the power supply is If the
Become something else. Furthermore, the rotation angle θ can be similarly predicted from equation (4).

When the seeding torque T exceeds the threshold value Tth (step 200), the sail nose device 1i8 temporarily stores the m torque T at that time as the initial value T (1) in the equation (6), and calculates the rotation angle at that time. Detector 50 angle pulse P (80)
Calculate the angular velocity ω0 from the time interval and temporarily store it as the cutoff 4IA value ω0 of the angular velocity ω (step 208).
That is, the angular velocity ω is inversely proportional to the time interval of the angular pulse P (80), and this time interval is this time 1M111! Since it is proportional to the number N of clock pulses accumulated within
ω is calculated as being inversely proportional to this clock pulse KN. The arithmetic unit 8 calculates these initial values [To, ωot
- Calculate the predicted final tightening torque To by using the formula (6) (f- Sub-step 210) 11 and until this final pre-side wefting torque Te exceeds the final 111M torque rs. New Vc for each angle valve P (Δ0)
The torque with ia To k is read and the angular velocity ωot' , 20
Similar to 6, step 214 is determined to be non-existent. If abnormal skin is detected in steps 214 and 216,
An alarm is issued (Step 204), and if there is no abnormality, tightening is stopped without issuing an alarm.

In this example, step 20 of detecting co-rotation
If the alarms 2 and 214, the alarms 20G and 211i for detecting an abnormality in the screw thread, and Ik are provided separately, the type of abnormality can be immediately known.

Further, in this embodiment, in steps 208 and 210, the new tightening torque T is calculated until the condition in step 212 is satisfied.
By replacing o and angular velocity ω0, the final child side tightening torque T@
However, it is very accurate because it is calculated.

The present invention may be configured as shown in FIG. 5. In other words, in the embodiment shown in FIG.
When the time t required to reach the torque after exceeding h (step 200) exceeds the setting II tl', it is determined in step 220 that co-rotation has occurred or that the bolt has entered the plastic region. It was pressed.

According to this embodiment, step 210, which takes a relatively long fi4X time, only needs to be executed once, so that the seed is passed through a device that tightens at high speed. Note that in FIG. 5, the same steps as in FIG. 3 are given the same reference numerals, so their description will not be repeated.

<Rotation Angle Method 2 Fig. 6 is a flowchart of the rotation angle method, and Fig. 7 is a diagram of its tightening characteristics. In the configuration shown in FIG. 1, the tightening rotation angle θ is detected by integrating the angle pulses P (80) output from the angle-side-out sushi 5.

Calculation! 1ktills first determines that the complete attachment has proceeded normally and entered the elastic range A of the bolt (Fig. 6, step 300), that is, the rotation angle θ from the starting point until the bolt enters the elastic range AK is Since it is vague depending on the body, read the setting -〇l that falls into the 1 elastic range A from the input/output device IO, compare it with the setting value θ1 of the rotation angle #, and continue this comparison until the 1 rotation angle 0 reaches this setting Has. Repeat the action. Steps 302, 304, 306 and 324, 3
26 is a 114 constant detection step similar to that shown in FIG. 3.5.

The arithmetic unit 8 then determines in a threshold value determination step 30B that the rotation angle 0 has exceeded the threshold value 0th.

This threshold value θth is preset as an angle smaller than the final target tightening angle θB, and is input to the input/output device 10.

When the rotation angle 0 reaches the threshold value θth K, the rotation angle 0 at that time is read as the initial value θ0 in the equation (4), and the angle pulse P of the rotation angle detector 50 at that time is read.
The angular velocity ωG is calculated from the time interval of ((step 314)) @That is, the angular velocity ω0 is the angular pulse P(
θ) is inversely proportional to the time interval, and this time interval is proportional to the number N of clock pulses accumulated within this time interval, so
After all, the angular velocity ω. is calculated as being inversely proportional to this clock pulse number N. This angular velocity ωG is compared with a preset angular velocity ω1 (step 316), and ω0 and ω
If it is 1, it is determined that both rotations occur, and an alarm is issued ff1 (step 318), and a tightening stop signal S' is output to stop tightening. That is, when co-rotation occurs, the rotational speed increases. If co-rotation does not occur,
In pre#J step 7 step 320, ilkm% 1,000 column tightening angle θ
ftk is calculated, and steps 314 and 31 are performed sequentially until this 1IIk final fam angle of exceeds the final target tightening angle θS.
6, III#Ik of 320: Returning knife, (stop determination step 32).

Further, in this embodiment, in steps 314 to 322, the initial values ω0, . Reread θ0 to find the final target tightening angle θf1
kJ! The present invention may be constructed as shown in FIG. 8, although it is very accurate.

That is, in the embodiment shown in FIG. 8, after the rotation angle 0 exceeds the threshold value 5th4 (step 308), the tightening amount (θ-
θ. ) exceeds (0g-11) (stop determination step 330), it will come to a tight stop, and the time required for this condition to be met, t.
When the value exceeds the set value t1'', it is determined in step 332 that there is co-rotation.

According to the example shown in FIG. 8, the execution of step 320, which takes a relatively long time, takes only l[g], so it is particularly suitable for a device that performs fastening at high speed.

Fig. 9 is a flowchart of the torque/rotation angle method, and Fig. 1θ is its tightening characteristic diagram. In FIG. 1O, point A indicates the beginning of the elastic region, and point B indicates the end of tightening. First, the input/output device 10
Accordingly, various values such as the set torque *Ta corresponding to point A and the rotation angle am=Ib-θa from point A to point B are input. Note that the change in tightening torque T with respect to rotation angle θ changes due to the frictional resistance of the joint surface between the nut and the object to be fastened, but since the contact pressure is small before entering the 1 elastic range, the difference in frictional resistance is the difference in tightening torque. There is little change in torque TK.

Therefore, if the torque that starts to increase rapidly at 1114It, which enters the elastic range, is the set torque Ta, then it is approximately positive 4IjI
The starting point of the K911 sex zone can be detected. Further, the rotation angle 08 is determined by the type of bolt, and since the axial force of the bolt is proportional to the elongation of the bolt, and this elongation is output as the rotation angle -, it is determined in accordance with the target axial force.

The calculation device 8 reads the set torque value Ta set by the input/output device 10, and also reads the digitalized tightening torque T.
Follow the angle pulse P (Δ-) and compare the two (torque determination step ? 1400), read the new MvC tightening torque Ttt, and repeat this comparison operation until the tightening torque T exceeds the set torque value Ta. Return page step 402, 4
04 and 406 are embroidery detection steps similar to those shown in FIG. 3 and the like.

The calculation device 8 calculates the angle pulse P(
Δ#), the rotation angle −=ΣΔa4 is calculated. Performance#
rts stores the rotation angle 0 when the condition in step 40G is met as the rotation angle θa at point A in FIG. Store 1] Rotation angle calculation step 41G) 11 That is, this rotation angle θX is θX=a−θa
It is calculated as The calculation device 8 then compares this rotation angle θX with the set rotation angle - Todoroki input in advance, and calculates aX (#
During S, the rotation angle #sk is calculated using a new [g1 rotation angle -] in step 410 of 4 degrees.

When Ijx, >#i, a tightening stop signal S is output (stop determination step 412) 11 In this embodiment, steps 402, 404. for abnormality detection are performed.
406 is provided in the torque determination step 400, but a similar abnormality detection step may be provided in other steps, for example, the stop determination step 412K, and each of these steps 4
00, 412. Also, in this embodiment, the rotation angle θX is directly compared with each setting 11Ta I $1 using the applied torque.

In reality, the rotational distance differs due to differences in frictional resistance, etc. 1. If the influence of inertia is corrected using equation (4), more accurate control becomes possible.

FIG. 11 is a flowchart of an embodiment in which such inertia correction is performed, and in step 414, the rotation angle e immediately before the power is cut off is determined. At the same time, the angular velocity ωO is calculated from the reciprocal of the angle/curse P (Δθ) and the reciprocal of the aN. Then, in step 416, the above equation (4) is calculated. (・Calculate the final rotation angle OC.

In the embodiments shown in FIGS. 9 to 11 above, since the torque T has increased by 1 m to the set torque value Ta9t (torque determination step 400), point A is detected, but this point A is based on the increase in torque TK. For example, the point A may be determined because this increase rate ΔT exceeds a pre-stored setting, or the change rate of this increase rate ΔT, that is, (ΔTn−ΔTn− 1) If the configuration is configured to determine A4'L' when the value exceeds a pre-stored setting value, errors due to differences in frictional resistance can be eliminated.
The initial stage of the elastic region can always be accurately determined.

@1' The figure is a flowchart showing an example of the latter case, in which the arithmetic unit S calculates the successive angular novels P(Δ#).
The difference Δ between each torque Tn r Tn-s read by
Tn.

Calculate and temporarily store ΔT n =Tn - Tl-1 (step 41B), then calculate and set the difference between successive differences ΔTn and Tn-s, that is, the rate of change ΔTn-Δ'rn-1Ik for the increase rate of 6 units. It is compared with the value α (torque determination step 420), and since this rate of change is greater than or equal to α, it is determined that the point is A.

Axial force snow layer method〉 The principle of the axial force management method is yes (there are some ideas, but here we will discuss 2)
Principles and based on them <Example f: Clarification.

First, we will explain the first original. FIG. 13 is a diagram showing the tightening characteristics. In this figure, the horizontal axis shows the tightening angle -1, the tightening torque T is shown above the vertical axis, and the axial force N is shown below the vertical axis. The axial force N of the bolt is proportional to the elongation of the bolt within the elastic range, and this elongation is proportional to the tightening angle #. Assume that the point where this proportional relationship is extended and the axial force N becomes 0 is θ;O. If we take this hypothetical point t at 0; If the bolts are of the same type, the linear axial force N and the tightening angle θ will always change. Therefore, if a predetermined final target axial force Ng is applied by the bolt, the final target tightening angle 0 is also uniquely determined. however,! It is difficult to measure the axial force N in the middle of attaching l.
Therefore, determining the e=00 origin described above is also a matter of national isolation.

On the other hand, the relationship between tightening angle 0 and tightening torque T is 41i! for bolts and nuts! ## Varies depending on the number of friction bodies such as the contact area with the binder. In Fig. 13, characteristic A indicates that the 41411 coefficient is small, and characteristic B indicates that it is large. Therefore, even if the strict target tightening angle θB is uniquely determined, the final target tightening torque Ts for this tightening angle asVc is Characteristics ^ and B are different. However, in the elastic range where the characteristic person B is the II lever, these straight lines pass through the origin, so T=ΔT/ΔθX# Therefore, the final target tightening torque Ts is, for characteristic A.

Ts(A) −(ΔT/Δ#)A

As described above, by multiplying the amount of change ΔT = Tfi-'rn-t in the tightening torque T with respect to the tightening angle Δθ; If the final target tightening torque T8 is calculated and the tightening is stopped when the tightening torque T reaches this torque T@, it is possible to properly tighten with the final target axial force Ns. In addition, # m/
! l! Since 1# is a constant, θ-TI=K(Tn-Tn-1), Reco...(7
) may be calculated.

$14 is a flow chart of an embodiment based on this first principle. The arithmetic unit 8 continues tightening to the threshold l1Tth set by the input/output device 10, while reading the torque T marked with * to the angle pulse P(Δ-), compares the two, and sequentially applies new tightening until T)7th is reached. Read the torque TIk and repeat this comparison operation (step 1 50Q), X?
y steps 5G2, 504, and 506 are abnormality detection steps similar to those in each of the embodiments described above.

The calculation device 8 calculates the tightening angle θ based on the angle pulse P(Δ#) outputted by the tightening angle detector 5 every time the set tightening angle is reached.

and the tightening torque Tn for the previous tightening angle θn-1 *
'rn-1ik I am temporarily getting used to it while rewriting it one by one. Then, when the condition of step SOO is satisfied, the above (7)
Calculate the formula (step SOS).

A final target tightening torque Tm corresponding to the target axial force Na is calculated, and this tightening torque Ts is stored. If the tightening torque To during tightening, which increases with the rotation of the electric motor 4, reaches 1 and the final target tightening torque T calculated in step 508, if the electric motor 4 stops, the target axial force Ns will be applied. This means that it can be tightened.

However, in this embodiment, considering the amount of additional tightening due to inertia immediately after the motor power is cut off, the final tightening torque T @ when the rotation has completely stopped is set to the lower side, and this 1! When the final tightening torque T exceeds the strict target tightening torque Ts, the power is cut off.
I have to. That is, in step 512, it is determined whether the final tightening torque Te exceeds the final target tightening torque Tik due to the inertia when the power is turned off at time θn, and the opening angle pulse P(Δθ )W6 is newly calculated from the current tightening torque To and rotational speed Nn by the angular position ω0.
(step 51O), and repeat the ljI calculations in steps 511 and 514 using these as new initial values (
Stop determination step), the required time t until the condition is met in step 5140 is determined by step! Similar to steps 102 and 506, steps 516 and 518
tl' Compare tL, 14 t') The presence or absence is determined. And these stays 7” 516.

If an abnormality is detected in step 518, an alarm is issued in step 50.
4) If there is no problem, stop tightening. Furthermore, F
The inertia rate J required for the calculation of the 1il prediction step 512
Constants such as the spring constant E and the like are input in advance by the input/output device 10 or stored in the memo jJ9.

The second principle of the axial force management method is explained in (2). FIG. 15 is a tightening characteristic diagram, in which the horizontal axis shows the tightening angle θ, the vertical axis shows the tightening torque T, and the vertical axis shows the axial force N below the m-axis. The axial force N of the bolt is proportional to the elongation of the bolt within the elastic range, and if this elongation is taken as the point kAIi at the tightening angle - ○, then the S force N passes through the origin as shown in the figure for the tightening angle #114 ! l
The top changes. Therefore, for bolts of the same type, if a predetermined axial force, that is, a liquid junction target axial force N1 is applied, then the final target tightening angle #■ is also uniquely determined.

However, it is difficult to measure the axial force N during tightening, and therefore determining the origin of θ=0 described above is also a matter of national security.

On the other hand, the tightening torque T changes depending on the magnitude of the friction coefficient of the contact portion between the bolt/nut and the fastened material. 15th
In the figure, the characteristic person shows the case where the number of M4I chants is small, the characteristic B is medium, and the characteristic C is large. Therefore, the final target tightening torque TII at the final target tightening angle Oa is 'I'm(A) due to the characteristics M, B and C.
It changes to Ts(B) and Ts(C).

Now, the tightening torque within the elastic range, that is, the threshold value Tth
If the tightening angle θ is the threshold tightening angle θt, and if this threshold tightening M Ik#t(A) for the characteristic AK is set, for example, it is clear from FIG. 15 that the following holds true. This threshold tightening angle θt
The tightening angle from (A) to the final target tightening angle axis, that is, the additional tightening angle 0x, is θI (A) = #s in the case of a characteristic person.
-θt(A), so the result holds true. By generalizing this equation, the following equation can be obtained.

FIG. 16 is a diagram showing this equation (8), and as is clear from this figure, as the tightening progresses from the threshold tightening angle θt as the starting point, the additional tightening angle jx=$−〇 The target tightening torque Ts of equation (8) for this additional tightening angle θxVc during tightening also increases. When this target tightening torque T becomes equal to the actual tightening torque T.

In other words, the curve of equation (8) moves parallel to the threshold tightening angles θt(A), #t(B), #1(C) with respect to the characteristics A, B, and C, and rc[lines A', B' , C', if the tightening is stopped, the tightening can be performed at the final target tightening angle θ, that is, the axial force N.

The gxy diagram is a 70-chart of the embodiment according to the second principle. In this diagram, the steps in FIG. 14 are shown.

Step 51G in which step 508 calculates the additional tightening angle ox
Since the only change is to step 522 in which the calculation of equation (8) is performed, the same steps will be given the same symbols and their explanation will be omitted.

<Proof Point Method Next, the calculation program PRG(Y) of the proof point method will be explained. FIG. 18 is a flowchart of the stress point method %1@FIG. 19 is its tightening characteristic diagram, and this embodiment is used for tightening steel bolts made of IIC steel or medium carbon steel. In other words, in the case of steel bolts, as shown in Fig. 19, a yield point Y clearly appears in the tightening characteristic curve 41, expressed as the tightening torque TILl versus the tightening rotation angle #, and the slope of this curve changes around this point. That is, the rate of increase ΔT of the torque T with respect to the predetermined rotation angle Δ# suddenly decreases. This license fee is
A sudden decrease in this rate of increase ΔT is detected and the tightening is stopped.

When the selection switch 14 selects the load-bearing point method, the arithmetic unit 8 sends a tightening operation start signal to the phase control circuit 11 at the beginning of the program PRG(Y), and the phase is controlled from the gate pulse generation circuit jli12. A gate pulse G is generated. For this reason, the semiconductor switch 3 is fired in phase synchronized with the trigger pulse G, a drive current begins to flow into the motor 4, and the motor 4 begins to rotate. As the bolt is tightened, the one-rotation angle detector 5 outputs an angle pulse P(Δ-) at every predetermined rotation angle Δθ. AD weird again! ! The I-device 7 outputs the ever-changing tightening torque T as a digital key signal.

The arithmetic device 8 reads the threshold value Tth set by the input/output device 1O, while reading the digitized tightening torque T for each angular pulse P (Δ0), compares the two (step 60o), and performs tightening. This comparison operation is repeated by sequentially reading new tightening torques T until the torque T exceeds the threshold @Tth. Note that the threshold Tth is the strict target tightening within the elastic range a shown in Fig. 19. The attached torque T is set as a slightly smaller torque value. Note that step 60
2.604.606 is an abnormality detection step V.

The arithmetic unit 8 calculates the rotation angle -yl-1 and the predetermined rotation angle Δ.
awk rotation angle #! Each tightening torque T in IK
Store n-凰 and Tゎ in built-in memory (RAM) K,
The zero arithmetic unit 8, which sequentially rewrites these tightening torques TB-s*Tl1l as the rotation progresses, calculates the difference ΔTゎ- between the tightening torques 'rn-, T at each predetermined rotation angle Δθ.
(Step 608), repeat this operation until this difference ΔTI) becomes less than or equal to the predetermined value 0 (Step 5). is the step 602
, 606, the set value J is set in steps 612 and 614.
' and t2', and fjlK of abnormal tightening is determined. Note that the difference ΔTn is also the increase rate of the tightening torque T with respect to the rotation angle 0, and this difference Arゎ is the increase rate of the tightening torque T with respect to the rotation angle 0.
If the following conditions are satisfied and no tightening abnormality is detected in steps 612 and 614, it is further determined whether the tightening torque T at this time is within the range of pre-stored set values TI and T. In step 616), if it is within the range T1 to T limit, it is assumed that the tightening is progressing normally and a tightening stop signal St is output, the power supply of the electric motor 4 is kept on, and the tightening is stopped. Step 6Hm, 61
4. If a tightening abnormality is detected in 616, a third alarm is issued (Step #g21 Figure is the tightening characteristic diagram. This example is suitable for tightening alloy bolts made of alloy steel or non-ferrous alloys. In other words, in alloy Pol F, as shown in Fig. 21, the rate of increase in the tightening torque characteristic curve decreases gently by 9 from the latter half of the elastic region, compared to the case of the steel bolt (Fig. 19). Therefore, in this example, the maximum increase rate Δ within the elastic region is
TIII is used to detect stress point B.

That is, in the 20th @, the tightening torque difference ΔT1 between the predetermined (b) rotation angles 68. In other words, the increase rate tX... step @50), this difference ΔTn is increasing or constant (step @H), the difference ΔTl1l is memorized as the maximum increase rate ΔTm (step 654), and this maximum increase rate ΔTag is sequentially newly determined. They can be replaced with a difference ΔTゎ. The step tab 856, @58 is the same as the step 11602, 604.
This is an anomaly detection step similar to . This result calculation device 8
The maximum increase rate ΔTag corresponding to the slope of the maximum slope line M in Figure @21 is stored in the memory (RAM) internally stored in the memory (RAM). When the condition of step 652 is satisfied and the difference ΔTn starts to decrease, a new calculation is made using the difference Δ (step S@O),
This difference ΔTrn is the maximum value Δ'r+w and constant aC (however, O<
Each of these steps 880 and @62 is repeated nine times until the value C. Since the steps have been given the same reference numerals, their description will not be repeated.

<Load control washer> Next, a tightening method using a 4R electric control washer will be explained.

Figure 22 is a diagram showing the tightening characteristics of this tightening method, showing the operation up to detecting the deformation start point C (hereinafter referred to as the first half operation) and the operation to detect a predetermined tightening amount after the deformation start point C (hereinafter referred to as the first half operation). There are various methods for each of the second half operations (referred to as the second half operation), and various embodiments can be constructed by combining each operation method after the deformation start point cstr.

First, the first half operation can be configured using the same calculation program as the stress point method. That is, the deformation starting point C is the same as the stress point method.
Similar to Y and 8 points in FIG. 21, this can be detected based on the flowchart in FIG. 18 or FIG. 20.

Therefore, regarding the first half of the operation!・Repeat the explanation.

The latter half of the operation will be explained below based on flowcharts of various embodiments shown in FIGS. 23 to 27.

FIG. 23 is a flowchart showing an example of this latter half operation, and the embodiment of FIG. 23 is based on the fact that the time t at the deformation start point CK is stored as a convention (step 70G), and the time t is calculated from the starting point of this time ta. t= t −ta is (
In step 7G, the time when the darkness starts to exceed the pre-stored darkness tII is regarded as the end point of transformation, and the stop is determined (step 704).
Tighten it to stop it.

The embodiment shown in FIG. 23 has a very simple configuration because the timer built in the arithmetic unit 18 can be used.

If the tightening speed is adjusted to the embodiment shown in FIG. 1 or FIGS. 32
When combined with the embodiment shown in the figure, the tightening can be stopped exactly at the deformation end point, which is preferable.

In the second half operation example of FIG. 24, the rotation angle 0 of the deformation interval m and ac is memorized as #8 (Stella 2tso), and the rotation angle 0o = θ-01 calculated from this rotation angle θ is stored in advance. Compare the angle θ with step 756.
) #. > When θ8, the tightening is stopped.

In addition, Figure 23! Steps 706 and 708 in Figure 24
.

710 is a step for abnormality detection similar to the previous embodiment.

In the example shown in FIG. 25, the deformation end point is determined because the tightening torque T increase 711 ΔT (step SOO) exceeds the pre-stored setting ΔTo1 using a procedure similar to that of FIG. 18. (stop determination step 802)
.

In the embodiment shown in FIG. 26, the minimum rate of increase ΔT in the plastic deformation range C-D is determined by a procedure similar to that in FIG. The rate of increase in rituals that started to increase after △T
In (step 8s6) is set to a predetermined value C・ΔTag (carrying C
>1) [(Stop Discrimination Step 1 85B) A 4k1 output is output to stop the tightening.

In the embodiment shown in FIG. 27, the angular velocity ω is first calculated from the reciprocal of the Kubarth number N within a predetermined rotation angle Δθ (step 5
oo) e [If the tightening speed is not controlled constant,
The angular velocity ω becomes approximately constant between the W-type deformation range C-0, and the angular velocity ω decreases as the torque with Km increases after the deformation end point, so the deformation end point is detected (stop determination Step 902).

The actual la? of the latter half of the operation in Figs. 11 is by appropriately combining the embodiments of each of the first half operations.

An optimal tightening method can be configured for different types of bolts and different tightening conditions.

In the examples of each tightening method described in detail above.

As shown in Figure 1, the tightening torque TIk is converted to the torque D determined by the strain gauge, and the rotation angle is converted to the angle pulse P.
(Δ-), but these torques T and 11 rotation angles can be obtained by various methods, and each of these methods will be explained below.

Factor 28 and FIG. 29 are block diagrams and flowcharts showing one embodiment thereof. In this embodiment, the tightening torque T is determined from the motor current, while the 5-point angle 0 is determined from the angle pulse P (Δ#) output by the tightening angle detector 5 at every required tightening angle ΔtI. It is.

In FIG. 28, 20 is a current detection resistor connected in series to the motor 4, and 22 is A that detects the motor current from the voltage across this resistor 200 and converts it into a digital signal IDK.
The D converter 24 determines the arbitrary rotation angle θ from this digital signal IDK. A second digital arithmetic unit calculates the tightening torque T and the angular velocity ω, and 26 is a memory that stores the arithmetic program of this second arithmetic unit. In this figure, parts that are the same as those in FIG.

The operation of this Mi1 column will be explained based on FIG. 29. By opening switch 2, the circuit dls changes to phase cl.
J @Circuit 11. The semiconductor switch 3 is ignited via the gate pulse circuit 12, and the electric motor 4 is started. The AD converter 22 quantizes the voltage across the resistor 20, which indicates the motor current, at an extremely shorter period than the AC power supply l, and converts it into a digital signal 1. The second arithmetic unit 24 integrates this digital signal ID over a half cycle or one cycle of the AC power source l to calculate the effective value of the current IM=ΣIDf: On the other hand, the time of the angular pulse P(Δθ) Calculate the angular velocity ω from the reciprocal of the number of clock pulses N accumulated within the interval "/) J,
Furthermore, the rotation angle θ is calculated by adding a predetermined rotation angle Δ− for each angle pulse P (Δθ) (Steasive 95G)
, this i# again! The second performance 1# device 24 also outputs two consecutive angular pulses P (Δθn).
From the difference in angular velocity by 1rθn1ld, the angular acceleration dω/d
tik)! (step 952).

On the other hand, in a DC motor, its output torque T is equal to φ
IM, where - is the magnetic flux and k is a constant. However, the torque T that actually contributes to tightening as an electric tightening machine becomes 5 as shown in the following equation, taking into account the influence of inertia (J -1,t and friction torque (Tf) during speed fluctuations).

T=niΦIv −J −−Tf Song/Song (9)
t The second calculation device 124 calculates the actual tightening torque T by calculating the equation (9) (step 954),
Book III - Chard. In this embodiment, the tightening torque is obtained from the electric motor IIJ411 electric itK, and one rotation angle 0 is calculated digitally based on the motor current and voltage and the speed characteristic equation of the motor.

In Fig. 30, 3o is a digital signal vD that is the motor voltage.
32 is a digital arithmetic unit 'a2, and 34 is a memory that stores the I* arithmetic program of this arithmetic unit 32. In this figure, the first.
Since the same parts as in Figure 28 have been given the same symbols, the 70th establishment cannot be repeated.

In this example, the closing of switch 2 causes the electric power to reach 1 m4.
When current flows through motor 1E, the voltage and voltage of motor 1E become AD.
The converter 22.30 converts the quantized digital signal ID to VDK at a cycle much faster than the AC power cycle.
, vD are sequentially read and integrated over half a cycle or one cycle of the AC power supply to calculate effective 111M = ΣID and vM = ΣVD (step 960 in Fig. 31).
).

Generally, the angular velocity ω of a II-wound commutator motor is determined by the following speed characteristic equation. - 0=, v ``R°! M a '''''' 0I where Kg is the armature resistance, . is the magnetic flux, and is a constant. The magnetic flux φ is generally a function of the electric current dLIM.

It is assumed that the change characteristics are stored in the memory 34 in advance.

The second arithmetic unit 32 receives the current IM4I:! output from the AD converters 22 and 30. The 14th reading is performed and a set of calculations are performed to calculate the angular velocity ω (step 962), while the above formula (9) is calculated to calculate the tightening torque Ttt that contributes to the actual WCd attachment (step 964) @2nd
The device 32 converts the angular velocity ω and the tightening torque T into electric current.
It is output every half cycle or every 1M1 period.

1 S is the angular velocity ω output by the calculation device 32 for this second operation. and torque T1 are read in sequence at predetermined time intervals, and the tightening angle l is calculated from the relationship 0=ω,1 (step 966
), these # and Tt- are output together with the tightening torque T at each predetermined tightening angle Δ#.

In the actual examples shown in FIGS. 1 to 31 above, the angular velocity ω changes as the tightening progresses, but the present invention can also be used for controlling the VC attainment so that the angular velocity ω remains constant. It is. For example, a device that uses the fact that the armature back electromotive force is proportional to the angle 4 degrees ω and controls the conduction angle of the semiconductor switch 3 according to changes in this back electromotive force to keep the angular velocity ω constant. be.

Figure $32 is a typical flowchart in which the angular velocity is kept constant at 6I4I in this way. In this embodiment, the motor voltage is converted into a digital signal vD by an AD converter, and this is integrated over a half cycle or one cycle VCIM of the AC power supply to obtain the effective value VM of the voltage (step 97G).
The motor current Lwt is calculated using the α-type speed characteristic equation (Step 972), and the tightening torque TTk is calculated from the above (9) (Step 974) using the voltage VM and current IM (Step 976). Now calculate the rotation angle -.

Furthermore, in some of the embodiments described above, when determining the tightening torque T from the motor current, the reduction in torque due to inertia and friction is increased.

Although it is possible to accurately detect the torque T [1], it is clear that the present invention can achieve the initial purpose even without these corrections.

As described above, this invention allows the selection of multiple tightening methods, so it is possible to freely select the IIk4 tightening method in response to differences in 1m attachment conditions and required tightening accuracy. Furthermore, since one device is sufficient, there is no need to prepare different tightening devices depending on the tightening method, and all processing up to turning the power on to the appropriate location is performed by digital signal processing.

Compared to analog signals, there is no phase delay during signal processing or errors caused by the signal holding means, and the tightening accuracy is noticeably improved. - In addition, if an abnormality detection step is provided in the torque determination step and stop determination step to detect tightening abnormalities from the time II# until these determination conditions are satisfied, it is possible to detect abnormalities such as bolt co-rotation and thread thread abnormalities. Can be detected reliably.

Furthermore, since this invention uses a digital arithmetic device,
It becomes necessary to add an abnormality detection step just by changing the program. Furthermore, by changing the various footings and programs, it is possible to flexibly deal with changes in the number of bolt types, and it has the effect of being highly versatile.

4-way Corresponding Explanation Figure 1 is a diagram of one embodiment of this invention, Figure 2 is a flowchart of its overall operation, Figures 3 and 4 are a flowchart and characteristic diagram of the torque method, FIG. 5 is a flowchart of another embodiment of the torque method.

Figures 6 and 7 are flow charts and characteristic diagrams of the 1g1 rotation angle method, Figure 8 is a 70-chart of another embodiment of the rotation angle method,
Figures 9 and 10 are 70-charts and their characteristic diagrams for the torque/rotation internal method, Figures 11 and 12 are 70-charts for other embodiments, and Figures 13 and 14 are for the axial force management method. 1
The characteristic diagram based on the principle and the flowchart of its embodiment, Figs. 1s and 16 are the same (the characteristic diagram based on the second principle, Fig. 17 is the 70-chart of the embodiment,
Figure 0, Figures 19 and 21 are the 70-chart and characteristic diagram of the force-bearing point method, 1K22WIJ is the characteristic diagram when using the load control willow washer, and Figures 23 to 27 are the 70-chart and characteristic diagram of the second half operation when using the load control lII washer. 28 to 32 are block diagrams and flow charts showing various embodiments for detecting torque and rotation angle.

4...Electric motor, 8...Digital calculation device, 9...
Memory %14...Selection switch, T...Tightening torque, -...Tightening rotation angle, S...Stop signal with -.

patent applicant Shibaura Manufacturing Co., Ltd. Agent: Patent Attorney Yama 1) Yu Moon ≠Figure 3 Figure 4 →θE Figure S Figure 7 notepad L:1 Diagram 13 figures Ding Figure 15 Figure 17 Figure 18 Figure 1q Figure 21 Figure 23 09th block )N ? Figure 32 θ9th

Claims (5)

[Claims] (1) For detecting the motive tightening torque and tightening rotation angle as digital signals, the torque method, single rotation angle method, torque/rotation angle method, axial force management method, ml force point method, and weight control washer are used. A memory that stores calculation programs according to the tightening method used, a selection switch that selects one of the calculation programs stored in this memory, and calculations performed according to the calculation program of the tightening method selected by this selection switch. #iii A bolt tightening device with selectable tightening method, characterized in that it is equipped with a digital arithmetic device that outputs a stop signal, and has a tightening method selection of 81 m. (2) The tightening torque is detected by a strain gauge that measures the tightening reaction force of the electric motor, and the rotation angle with Ml is calculated by integrating the angle pulses output by the rotation angle detector for each set rotation angle.
A port tightening device with a selective tightening method according to Claim IJA. (3) Tightening torque is Den IIJ4#! The tightening method selective bolt tightening device according to claim 1, wherein the rotation angle is determined from the current and the rotation angle is determined by integrating the angular pulses output by the rotation angle detector for each set rotation angle. (4) The tightening torque is determined by the exciter current, and the tightening rotation angle is calculated digitally using the motor current and the machine voltage using the motor's 4-degree characteristic equation. Porto tightening device with selectable tightening method. (5) The motor is phase controlled so that the angular angle is constant, the tightening torque is calculated digitally from the motor voltage and the mounting characteristic equation, and the tightening rotation angle is calculated from the product of the angular velocity and time. A tightening method selective bolt tightening M wrinkle according to claim 81.