JP6621013B2 - Method and system for determining whether screw tightening is good or bad - Google Patents

Description

In the present invention, in order to confirm an appropriate screw tightening state in a screw tightening operation using a required screw tightening device, a reference value and an allowable range for various detection values for achieving an appropriate screw tightening state are set. Then, in the system for determining the quality of the screw tightening state based on the detection value in the screw tightening state, when the detection value in the required screw tightening operation is outside the preset allowable range, it is slightly larger than the allowable range. By temporarily setting a preliminary allowable range to be performed, and performing the pass / fail determination of the detected value again, the determination in the vicinity of the pass / fail boundary line in the screw tightened state pass / fail determination is more appropriately achieved. The present invention relates to a method and a system for determining whether or not a screw is tightened.

  The present applicant first uses a screw tightening device configured to rotationally drive a rotary tool such as a driver bit by driving means such as an electric motor, and when performing a required screw tightening operation by manual operation, Screws with screw tightening pass / fail judgment means that can detect screw tightening defects such as screw galling and screw floating in the screw holes easily and simply with a relatively simple configuration at a low cost in an appropriate and reliable manner. A fastening device was developed and patented (see Patent Document 1).

The screw tightening device described in Patent Document 1 includes a rotation amount detection means provided for detecting a rotation amount based on the rotation speed and rotation time associated with the rotation drive of the rotary tool, and a screw head at the tip of the rotary tool. A screw tightening reference time setting means for setting a screw tightening reference time by pressing the rotary tool in the axial direction at the time when the screw shaft tip of the screw fitted with the screw is positioned and abutted against the screw hole of the object to be screwed. After the screw tightening reference time is set, the screw tightening start time setting means for starting the rotary tool driving means to set the screw tightening start time and the screw positioned and abutted on the screw hole are rotated. A screw tightening completion time point detecting means for detecting a screw tightening completion time point when a load torque generated in the rotary tool reaches a set load torque value, and after setting the screw tightening reference time point It is determined whether or not the rotation amount of the rotary tool is within an allowable range from a screw tightening start time for starting the driving means of the rotary tool to a time point when the screw tightening is completed, in comparison with a preset reference value. , Screw tightening quality determination means for determining screw tightening quality,
It consists of the provided structure.

Further, the present applicant, in a predetermined screw tightening operation by the electric screwdriver, determines the rotation amount of the electric motor from the start of screw tightening in the first screw tightening operation to the time of clutch operation by the clutch mechanism accompanying the completion of screw tightening. A clutch that is detected and recorded by the detecting means, sets the rotation amount detected and recorded as a target rotation amount (including an allowable range), and then completes screw tightening from the start of screw tightening in a predetermined screw tightening operation. By sequentially detecting the rotation amount of the electric motor until the clutch operation time by the mechanism by the rotation amount detection means, and comparing the rotation amount detected at the clutch operation time with the target rotation amount (including an allowable range), An automatic screw tightening control method and device configured to judge whether the screw tightening state is good or bad was developed and a patent application was filed. References 2).

  Further, the applicant includes an electric motor, a drive switch for driving the electric motor, and a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism and a torque limiter, and the drive A switch operating member for operating a switch, a torque limiter operation detecting sensor for detecting a torque-up operation of the torque limiter, an electric motor control circuit for controlling driving and stopping of the electric motor, and rotation of the driver bit or the electric motor The amount of rotation of the driver bit or the electric motor from the start of screw tightening to the time of torque-up operation by the torque limiter upon completion of screw tightening using an electric screwdriver provided with a rotation amount detecting means for detecting the amount Are sequentially detected by the rotation amount detecting means, and the torque is increased. Developed an automatic screw tightening control method and device configured to judge the quality of the screw tightening state by comparing the rotation amount detected at the time of operation with the target rotation amount (including the allowable range). (See Patent Document 3).

Furthermore, the present applicant comprises an electric motor, a drive switch for driving the electric motor, and a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism, and the drive switch The switch operating member to be operated and the load current obtained in the electric motor based on the load torque (reaction force) applied to the driver bit in the electric motor are detected, and the load current has reached a preset set value. A load current detecting means for outputting a predetermined torque-up detection signal and an electric motor control circuit for controlling the driving and stopping of the electric motor, respectively, using an electric screwdriver provided to the load current detecting means. The load current set value for outputting the torque-up detection signal can be variably set by a required communication control means. The load current value from the beginning of tightening up the torque-up detection time associated with completion of the screw tightening detected by the load current detection means, said detected load current value to the torque-up detection time preset load current value The automatic screw tightening control method and apparatus configured to determine whether or not the screw tightening state is good by comparing with the above has been developed, and a patent application has been filed (see Patent Document 4).

Japanese Patent No. 5390226 International Publication No. 2014/065066 International Publication No. 2014/192469 International Publication No. 2015/045871

As described above, in the conventional screw tightening control device, in order to determine an appropriate screw tightening state, for example, detection of a time or amount of rotation until a required screw tightening state is detected, or screw tightening in the screw tightening state is performed. By detecting torque, etc., the detection value is converted to a digital value and set to be compared with a preset reference value (including the allowable range), and set to determine whether the screw tightening state is good or bad System has been built.

However, when the screw tightening operation is performed using the required screw tightening device in the system constructed so as to perform the pass / fail judgment of the screw tightening state as described above, for example, the driver bit detected in the screw tightening state is rotated. When the detected value composed of the load current value proportional to the rotation amount of the electric motor to be driven or the screw tightening torque value of the electric motor is compared with each of the preset reference value and its allowable range, the detected value is the reference value. If it is slightly out of the permissible range, the pass / fail determination result of the screwed state is determined to be defective.

  Accordingly, when the screw tightening state is judged as good or bad, it is necessary to forcibly interrupt the operation of the screw tightening device and check the screw tightening state. However, as described above, when the detected value detected in the screw tightening state slightly deviates from the allowable range of the reference value, even if the pass / fail determination result of the screw tightening state is determined to be defective, It has been confirmed that there is no particular problem even if it is recognized that the screw is properly tightened. Therefore, it is difficult to determine that the screw tightening state is inferior and to forcibly interrupt the operation of the screw tightening device in the result of determining whether the screw tightening state is good or bad.

  Therefore, the present inventor has conducted intensive studies and studies to solve the problems of the system for determining the quality of the screw tightening state in the conventional screw tightening operation as described above. When the screw tightening failure is determined, the reference value (Rv) within the allowable range value (Rv ± α) (Rv + α ≧ Dv ≧ Rv−α) with respect to the detected value (Dv) detected in the screw tightening state. ) (Rv + α <Dv <Rv−α), the allowable range value (Rv ± β: where β> α) is set by slightly expanding the initially set allowable range value (Rv ± α). The detection value detected in the screw tightening state is changed to the reference value allowable range value (Rv) in which the reference value has been changed by performing the pass / fail judgment on the detection value (Dv) again. Within the range of ± β) If (Rv + β ≧ Dv ≧ Rv−β) is satisfied, it is determined that the screw is properly tightened, and the conventional problem is solved, and the proper screw tightening is determined more appropriately and efficiently. It has been found that it is possible to determine whether the screw tightening state is good or not and improve the efficiency of the screw tightening operation.

  As described above, in the first screw tightening pass / fail judgment, it is determined that the screw tightening is defective, and the allowable range value (Rv ±) of the reference value (Rv) with respect to the detected value (Dv) detected in the screw tightening state. When changing the setting of α) to an allowable range value (Rv ± β: β> α) that is slightly enlarged and changed, the operator of the required screw tightening device can easily and easily operate, for example, gripping of the screw tightening device By providing an appropriate switch operation member or the like on a part of the outer periphery of the part casing, it can be configured simply. The setting change as described above can be automatically performed.

Therefore, an object of the present invention is to detect a detection value including a load current value proportional to a rotation amount of an electric motor that rotates a driver bit detected as a screw tightening state in a screw tightening operation or a screw tightening torque value of the electric motor as an initial value. In a system for determining pass / fail in comparison with a set reference value and an allowable range thereof, it is possible to immediately perform pass / fail determination again when the detected value of the screw tightening state deviates even slightly from the pass / fail determination boundary line. In this way, it is possible to eliminate the determination of abnormalities more than necessary in the conventional quality determination, achieve more appropriate quality determination of the screw tightening state, and improve the screw tightening work efficiency. An object is to provide a method and a system for determining whether or not a screw is tightened.

In order to achieve the above object, a screw tightening quality determination method according to claim 1 of the present invention includes an electric motor, a drive switch for driving the electric motor, and a drive output shaft of the electric motor. A switch operating member that operates the drive switch, a clutch operation detection sensor that detects a clutch operation of the clutch mechanism, and a drive and stop control of the electric motor, each of which includes a driver bit coupled via a deceleration mechanism and a clutch mechanism An electric motor control circuit for performing the rotation, a rotation amount detection means for detecting the rotation amount of the electric motor, and a driver from the start of screw tightening by the clutch mechanism to the clutch operation time at the completion of screw tightening by the rotation amount detection means control for detecting recording the rotation of the electric motor for rotating the bit as the amount of rotation of the screw tightening state (detected value) Preparative, while using the screwing apparatus as an electric screwdriver provided respectively,
At the time of screw tightening operation , the control unit compares the rotation amount ( detection value ) of the electric motor detected as the screw tightening state with the rotation amount ( reference value ) set in advance and its allowable range and determines whether it is acceptable or not. In the method for determining pass / fail of the screw tightening state set to perform
The amount of rotation of the screw fastening state detected in the screwing operation (detection value), the initial set rotation amount (reference value) and a result of the quality determination compared to its allowable range, the detection value When the reference value and the allowable range thereof are deviated, the preliminary allowable range for expanding the allowable range of the reference value is temporarily set and changed so that the detection value is determined again. Features.

The screw tightening quality determination method according to claim 2 of the present invention includes an electric motor, a drive switch for driving the electric motor, and a drive output shaft of the electric motor via a reduction mechanism and a clutch mechanism. A switch operating member for operating the drive switch, a clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling the driving and stopping of the electric motor, Load current detecting means for detecting a load current obtained in the electric motor based on a load torque (reaction force) applied to the driver bit in the electric motor control circuit; and screw tightening by the clutch mechanism by the load current detecting means. Screw tightening of the electric motor from the start time to the clutch operation time when screw tightening is completed Load current value of the load current value screwing state is proportional to the click value and a control unit for detecting recorded as (detection value), while using the screwing apparatus as an electric screwdriver provided respectively,
In the screw tightening operation, the control unit compares the load current value (detected value) of the electric motor detected as the screw tightened state with the load current value (reference value) set in advance and its allowable range, In the pass / fail judgment method of the screw tightening state set to perform the pass / fail judgment,
As a result of performing the pass / fail judgment by comparing the load current value (detected value) in the screw tightening state detected in the screw tightening operation with the initially set load current value (reference value) and its allowable range. When the value deviates from the reference value and the allowable range thereof, the preliminary allowable range for expanding the allowable range of the reference value is temporarily changed and set so that the determination of the detected value is performed again. It is characterized by that.

The screw tightening pass / fail judgment system according to claim 3 of the present invention is coupled to an electric motor, a drive switch for driving the electric motor, and a drive output shaft of the electric motor via a reduction mechanism and a clutch mechanism. A switch operating member that operates the drive switch, a clutch operation detection sensor that detects a clutch operation of the clutch mechanism, an electric motor control circuit that controls drive and stop of the electric motor, a rotation amount detecting means for detecting the amount of rotation of the electric motor, the rotation of the electric motor for rotating the screwdriver bit from the start of the screw tightening by the clutch mechanism to the clutch operation time during the tightening completion by the rotation amount detecting means And a control unit for detecting and recording the rotation amount (detection value) in the screw tightened state. With using the screw tightening device as a driver,
At the time of screw tightening operation, the control unit compares the rotation amount (detection value) of the electric motor detected as the screw tightening state with the rotation amount (reference value) set in advance and its allowable range and determines whether it is acceptable or not. In the screw tightening pass / fail judgment system configured to perform
Means for comparing the rotation amount (detection value) in the screw tightening state detected in the screw tightening operation with the initially set rotation amount (reference value) and its allowable range, and performing pass / fail judgment;
The quality determination of the result of the case wherein the detection value is departing from the allowable range of the reference value and its, temporarily changes the setting of the allowable range of the pre-expanding the allowable range of the reference value, the detection value And a means for performing pass / fail determination again.

The screw tightening pass / fail judgment system according to claim 4 of the present invention includes an electric motor, a drive switch for driving the electric motor, and a drive output shaft of the electric motor via a reduction mechanism and a clutch mechanism. A switch operating member for operating the drive switch, a clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling the driving and stopping of the electric motor, Load current detecting means for detecting a load current obtained in the electric motor based on a load torque (reaction force) applied to the driver bit in the electric motor control circuit; and screw tightening by the clutch mechanism by the load current detecting means. Screw tightening of the electric motor from the start time to the clutch operation time when screw tightening is completed And a control unit that detects recording the load current value proportional to the torque value as a load current value of the screw tightening state (detected value), the use of screw tightening device as an electric screwdriver provided respectively,
In screw tightening operation, the load current value ( detected value ) of the electric motor detected as the screw tightened state in the control unit is compared with the load current value ( reference value ) set in advance and its allowable range, and the quality is determined. In a screw tightening pass / fail judgment system configured to make a judgment ,
Means for comparing the load current value ( detected value ) of the screw tightening state detected in the screw tightening operation with the initially set load current value ( reference value ) and its allowable range,
The quality of the determination result, if the detection value is departing from the allowable range of the reference value and its, temporarily changes the setting of the allowable range of the pre-expanding the allowable range of the reference value, again of the detection value means for performing quality determination of, characterized in that it consists structure provided with.

According to the screw tightening quality determination method and system according to claims 1 and 3 of the present invention, an electric motor, a drive switch, a driver bit coupled via a speed reduction mechanism and a clutch mechanism are provided, and the clutch A clutch operation detection sensor for detecting the clutch operation of the mechanism, an electric motor control circuit for controlling driving and stopping of the electric motor, a rotation amount detection means for detecting the rotation amount of the electric motor, and the rotation amount detection means. A control unit that detects and records the amount of rotation of the electric motor that rotates the driver bit from the start point of screw tightening by the clutch mechanism to the clutch operation point when screw tightening is completed as a rotation amount (detection value) of the screw tightening state; use screwing apparatus as an electric screwdriver provided respectively, screwing the required screwing operation In performing quality determination of the state, the rotation of the electric motor is detected as screw tightening state (detection value), as compared to previously initially set rotation amount (reference value) and the allowable range, performs the quality judgment If the detected value deviates from the reference value and the allowable range thereof, the preliminary allowable range for immediately expanding the allowable range of the reference value is immediately set and changed, and the pass / fail determination of the detected value is performed again. By setting so as to be performed, it is possible to quickly and appropriately perform the determination in the vicinity of the pass / fail boundary line in the pass / fail determination of the screw tightening state by a simple operation, and improve the work efficiency of the screw tightening work. be able to.

According to the screw tightening quality determination method and system according to the second and fourth aspects of the present invention, the clutch includes the electric motor, the drive switch, the driver bit coupled via the speed reduction mechanism and the clutch mechanism, and the clutch. Based on a clutch operation detection sensor that detects a clutch operation of the mechanism, an electric motor control circuit that controls driving and stopping of the electric motor, and a load torque (reaction force) applied to the driver bit in the electric motor control circuit A load current detecting means for detecting a load current obtained in the electric motor; and a load tightening torque value of the electric motor from a start time of screw tightening by the clutch mechanism to a clutch operation time when screw tightening is completed by the load current detecting means. Detect and record the proportional load current value as the load current value (detected value) in the screw tightened state The load current value (detected value) detected as the screw tightening state is used to determine whether the screw tightening state in the required screw tightening work is good or bad by using a screw tightening device as an electric screwdriver provided respectively. ) Is compared with a load current value (reference value) that has been initially set in advance and its allowable range, and the pass / fail judgment is made. When the detected value is outside the reference value and the allowable range, the reference value is immediately By temporarily setting and changing the preliminary allowable range for expanding the allowable range of the detection value and performing the pass / fail determination of the detected value again, the vicinity of the pass / fail boundary line in the pass / fail determination of the screwed state is obtained. The determination of the case can be performed quickly and appropriately by a simple operation, and the work efficiency of the screw tightening operation can be improved .

According to the screw tightening state pass / fail determination method and system according to claims 1 to 4 of the present invention, when determining the screw tightening state pass / fail, the allowable range of the initial reference value and the allowable range of the preliminary reference value are determined. The change setting operation can be performed more easily, and the operation for resetting to the allowable range of the reference value of the initial setting can also be performed easily, which is sufficient to improve the work efficiency of the screw tightening operation. Can contribute.

It is a schematic explanatory drawing which shows one structural example of the screw fastening apparatus for constructing the system which implements the quality determination method of the screw fastening state based on this invention, and its control system. It is a flowchart figure which shows the quality determination program for performing the quality determination of the screw fastening state in the case of performing the screw fastening operation | work with the screw fastening apparatus shown in FIG.

  Next, an embodiment of a screw tightening quality determination method according to the present invention will be described in detail below with reference to the accompanying drawings in relation to a system that implements the method.

[ Configuration Example of Screw Tightening Device for Implementing the Present Invention ]
FIG. 1 is a schematic explanatory diagram showing a configuration example of a screw tightening device and its control system for constructing a system for carrying out a screw tightening quality determination method according to the present invention. That is, in FIG. 1, reference numeral 10 indicates a screw tightening device as an electric screwdriver. In the gripping portion of the screw tightening device 10, an electric motor 12, a drive switch 13 for driving the electric motor 12, A speed reduction mechanism 16 and a clutch mechanism 18 coupled to a drive output shaft (not shown) of the electric motor 12 are incorporated, and a rotary tool including a driver bit 20 is coupled via the clutch mechanism 18. .

  In the screw tightening device 10, the switch operating member 14 that operates the drive switch 13 of the electric motor 12, the electric motor control circuit 22 that performs drive control and stop control of the electric motor 12, and the clutch operation of the clutch mechanism 18. A clutch operation detection sensor 28 for detection is provided. The electric motor control circuit 22 is provided with a rotation amount detecting means 24 for detecting the rotation amount of the precursor electric motor 12. Furthermore, load current detection means 26 for detecting the load current obtained in the electric motor 12 based on the load torque (reaction force) applied to the driver bit 20 is appropriately provided.

  In the screw tightening device 10, a brushless motor can be suitably used as the electric motor 12. Further, the switch operating member 14 for operating the drive switch 13 to drive the electric motor 12 can be configured as a known lever member provided on the outer periphery of the grip portion of the electric driver 10, for example.

  Further, in the screw tightening device 10, the rotation amount detection means 24 for detecting the rotation amount of the electric motor 12 applies a pulse generated at the time of detecting the magnetic pole to the Hall element that detects the magnetic pole of the rotor in the brushless motor. It can be provided as a means for counting. In this case, the count number of the pulses detected by the rotation amount detection means 24 can be detected and recorded as a rotation amount correlated with the screw tightening rotation amount in the screw tightening operation accompanying the rotation of the driver bit 20.

  Furthermore, the load current detection means 26 for detecting the load current of the electric motor 12 can be provided as means for detecting the load current in the power supply circuit of the electric motor 12. In this case, the detected load current value of the electric motor 12 can be detected and recorded as a load current value correlated with a screw tightening torque value in the screw tightening operation accompanying the rotation of the driver bit 20.

  As the clutch mechanism 18, for example, a clutch plate is attached to the output shaft of the speed reduction mechanism 16, and a clutch ball is elastically engaged with the clutch plate in the axial direction. When a load torque (reaction force) above a certain level is applied to the output shaft, the clutch plate gets over the clutch ball, and the transmission of the rotational driving force to the bit holder that engages and holds the driver bit 20 is cut off. Thus, the screw can be tightened with a preset torque. In this case, when the clutch ball is elastically engaged with the clutch plate, the screw tightening torque can be set by appropriately adjusting the elasticity.

  The clutch operation detection sensor 28 for detecting the clutch operation of the clutch mechanism 18 includes, for example, a limit switch that operates by displacement of the clutch plate at the time of clutch operation, and an internal that constitutes the speed reduction mechanism 16 that idles at the time of clutch operation. It can be configured by a known means such as a magnetic sensor for detecting the rotation of the gear.

  Therefore, the screw tightening device 10 is provided with a control unit 30, and the CPU 32 switches the switch when starting the screw tightening operation for the electric motor control circuit 22 provided in the electric motor 12 of the screw tightening device 10. A drive switch operation signal S13 obtained by the operation of the drive switch 13 operated by the operation member 14 is input, and based on this drive switch operation signal S13, an electric motor drive control signal S22a is output and the electric motor control circuit 22 is output. To control the driving of the electric motor 12.

  When a required screw tightening operation is performed by driving the electric motor 12, the CPU 32 detects the rotation amount detected by the rotation amount detection means 24 at the start of driving the electric motor 12 accompanying the start of the screw tightening operation. Based on the signal S24, the rotation amount of the electric motor 12 is set to be detected and recorded.

  Similarly to the above, the load proportional to the screw tightening torque value based on the load current detection signal S26 detected by the load current detecting means 26 at the start of driving of the electric motor 12 accompanying the start of the screw tightening operation. Set to detect and record the current value.

  Then, the CPU 32 detects the amount of rotation of the electric motor 12 at the clutch operation time point obtained based on the clutch operation detection signal S28 detected by the clutch operation detection sensor 28 at the clutch operation time point of the clutch mechanism 18. Then, it is set to detect and record as a detection value Dv of a screw tightening state to be described later.

  Similarly to the above, the load current value proportional to the screw tightening torque value at the clutch operation time point obtained based on the clutch operation detection signal S28 detected by the clutch operation detection sensor 28 at the clutch operation time point of the clutch mechanism 18. Is detected and recorded as a detection value Dv of a screw tightening state to be described later.

  As described above, when the clutch operation is detected by the clutch operation detection sensor 28, the electric motor stop control signal S 22 b is output via the CPU 32 and is input to the electric motor control circuit 22. The motor 12 is configured to be stopped.

  In the screw tightening device 10, the CPU 32 of the control unit 30 uses the reference value (Rv) and the allowable range value (Rv ± α) for determining whether the screw tightening state detection value Dv is acceptable. ) Is initially set, and the detection value Dv of the screw tightening state is compared with an allowable range value (Rv ± α) of the reference value (Rv), and the pass / fail judgment is made.

  Accordingly, in this case, if the detected value Dv is within the allowable range of the reference value (Rv) (Rv + α ≧ Dv ≧ Rv−α), the screw tightening state is determined to be appropriate, and the CPU 32 determines the screw tightening state. A screw tightening determination signal S40 for “appropriate” is output, and the determination content is appropriately displayed on the display 40.

  In this case, if the detected value Dv is outside the allowable range of the reference value (Rv) (Rv + α <Dv <Rv−α), the screw tightening state is determined to be abnormal, and the CPU 32 sets the screw tightening state. A screw tightening determination signal S40 for “abnormal” is output, and the determination content is appropriately displayed on the display 40.

  Next, in the screw tightening apparatus 10 having the above-described configuration example, a method and a system for performing pass / fail determination of the screw tightening state according to the present invention will be described based on a screw tightening state pass / fail determination program shown in FIG.

Examples of the present invention
FIG. 2 is a flowchart showing a pass / fail determination program for determining pass / fail of the screw tightening state when the screw tightening operation 10 shown in FIG. 1 is performed.

First, a required screw tightening operation is started using the screw tightening device 10 described above (STEP-1). Then, the screw tightening state is detected according to the screw tightening process of the screw tightening device 10 described above (STEP-2). In this case, as shown in FIG. 1, the rotation amount detecting means 24 rotates the driver bit 20 detected by the control unit 30 from the start of screw tightening by the clutch mechanism 18 to the clutch operation time when screw tightening is completed. The rotation amount of the electric motor 12 is detected and recorded in the CPU 32 as the detection value Dv of the screw tightening state (STEP-3). Alternatively, as shown in FIG. 1, the screw current of the electric motor detected by the control unit 30 from the start of screw tightening by the clutch mechanism 18 to the time of clutch operation accompanying the completion of screw tightening by the load current detecting means 26. A load current value proportional to the value is detected and recorded in the CPU 32 as a detected value Dv of the screw tightening state (STEP-3).

Therefore, in the CPU 32 , the reference value Rv (the rotation amount or the load current value set in advance for performing the pass / fail determination corresponding to the detected value) and the allowable range value thereof, which are initially set, are set. The data S52 relating to (Rv ± α) and the detected value Dv of the screw tightening state are compared, and whether the detected value Dv is within an allowable range of the reference value Rv (Rv + α ≧ Dv ≧ Rv−α) is acceptable. A determination is made (STEP-4).

  If the detected value Dv is within the allowable range of the reference value Rv (Rv + α ≧ Dv ≧ Rv−α) as a result of the quality determination of the screw tightening state, it is determined that the screw tightening state is appropriate, and the CPU 32 performs screw tightening. A screw tightening determination signal S40 for setting the state to “appropriate” is output, and the determination content is appropriately displayed on the display 40 (STEP-5). Then, the required screw tightening operation is completed.

  However, if the detected value Dv is outside the allowable range of the reference value Rv (Rv + α <Dv <Rv−α) as a result of the quality determination of the screw tightening state, it is determined that the screw tightening state is abnormal, and the CPU 32 A screw tightening determination signal S40 for setting the screw tightening state to “abnormal” is output, and the determination content is appropriately displayed on the display 40 (STEP-6).

In this case, an operator who operates the screw tightening device 10 operates, for example, a switch mechanism 50 (see FIG. 1) provided on a part of the outer periphery of the gripping part casing of the screw tightening device to allow the initial set reference value. On the basis of the instruction signal S50 for changing the range setting, the CPU 32 sets a preliminary allowable range value (Rv ± β: where α <β) slightly larger than the allowable range value (Rv ± α) of the reference value Rv of the initial setting. ) Regarding the data S54 is temporarily changed (STEP-7).

  Note that in this case, temporary data to the data S54 relating to the preliminary allowable range value (Rv ± β: where α <β) slightly larger than the allowable range value (Rv ± α) of the initial reference value Rv is used. When changing the setting, it is possible to automatically change the setting based on the pass / fail judgment that the screw tightening state is “abnormal” without any operator operation (STEP-7).

  Therefore, a pass / fail judgment is made again on the detected value by changing the setting of the allowable range value (Rv ± β: where α <β) with respect to the reserve reference value Rv (STEP-8). As a result, the detected value If Dv is within the allowable range of the reference value Rv (Rv + β ≧ Dv ≧ Rv−β), it is determined that the screw tightening state is appropriate, and the CPU 32 generates a screw tightening determination signal S40 that sets the screw tightening state to “appropriate”. The contents of the determination are appropriately displayed on the display 40 (STEP-9). Then, the required screw tightening operation is completed.

  If the detected value Dv is outside the allowable range of the reference value Rv (Rv + β <Dv <Rv−β) as a result of the quality determination of the screw tightening state, the screw tightening state is determined to be abnormal, and the CPU 32 A screw tightening determination signal S40 for setting the screw tightening state to “abnormal” is output, and the determination content is appropriately displayed on the display 40 (STEP-10). Then, the required screw tightening operation is completed, and the operation of the screw tightening device 10 is interrupted, and a confirmation operation for an abnormality in the screw tightening state is performed.

  The preferred embodiments of the present invention have been described above. However, the screw tightening device for determining the quality of the screw tightening state according to the present invention is not limited to the above-described embodiments, for example, from an air driver or an impact driver. The present invention can also be suitably applied as a screw fastening device. In addition, the detection value of the screw tightening state detected by the screw tightening device to determine whether the screw tightening state is good or not is not limited to the above-described embodiment, and various conventionally known screw tightening state detection values may be used. Can be targeted. In addition, many design changes can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Screw fastening apparatus 12 Electric motor 13 Drive switch 14 Switch operation member 16 Deceleration mechanism 18 Clutch mechanism 20 Driver bit 22 Electric motor control circuit 24 Rotation amount detection means 26 Load current detection means 28 Clutch operation detection sensor 30 Control part 32 CPU
40 indicator 50 switch mechanism S13 drive switch operation signal S22a electric motor drive control signal S22b electric motor stop control signal S24 rotation amount detection signal S26 load current detection signal S28 clutch operation detection signal S40 screw tightening state determination signal S50 allowable range setting change instruction Signal S52 Data relating to initial setting S54 Preliminary data Dv Detection value Rv of screw tightening state Rv Reference value α Allowable range value for initial set reference value β Allowable range value for preliminary reference value

Claims (4)

An electric motor, a drive switch for driving the electric motor, a switch operating member for operating the drive switch, comprising a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism and a clutch mechanism; A clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling driving and stopping of the electric motor, a rotation amount detection means for detecting the rotation amount of the electric motor, and the rotation amount A control unit for detecting and recording a rotation amount (detection value) of an electric motor that rotates a driver bit from a start point of screw tightening by the clutch mechanism to a clutch operation point upon completion of screw tightening by a detection unit. And using a screw tightening device as an electric screwdriver provided respectively,
At the time of screw tightening operation , the control unit compares the rotation amount ( detection value ) of the electric motor detected as the screw tightening state with the rotation amount ( reference value ) set in advance and its allowable range and determines whether it is acceptable or not. In the method for determining pass / fail of the screw tightening state set to perform
The amount of rotation of the screw fastening state detected in the screwing operation (detection value), the initial set rotation amount (reference value) and a result of the quality determination compared to its allowable range, the detection value When the reference value and the allowable range thereof are deviated, the preliminary allowable range for expanding the allowable range of the reference value is temporarily set and changed so that the detection value is determined again. A method for determining whether or not a screw tightening state is characteristic. An electric motor, a drive switch for driving the electric motor, a switch operating member for operating the drive switch, comprising a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism and a clutch mechanism; A clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling driving and stopping of the electric motor, and a load torque (reaction force) applied to the driver bit in the electric motor control circuit The load current detecting means for detecting the load current obtained in the electric motor based on the above), and the screw tightening of the electric motor from the start time of screw tightening by the clutch mechanism to the clutch operation time when the screw tightening is completed by the load current detecting means The load current value proportional to the torque value is changed to the load current value ( And a control unit that detects recording as detection value), while using the screwing apparatus as an electric screwdriver provided respectively,
In the screw tightening operation, the control unit compares the load current value (detected value) of the electric motor detected as the screw tightened state with the load current value (reference value) set in advance and its allowable range, In the pass / fail judgment method of the screw tightening state set to perform the pass / fail judgment,
The load current value of the screwing state detected in screwing operation (detection value), the initial set load current value (reference value) and a result of the quality determination compared to its allowable range, the detection When the value deviates from the reference value and the allowable range thereof, the preliminary allowable range for expanding the allowable range of the reference value is temporarily changed and set so that the determination of the detected value is performed again. A method for determining whether or not a screw tightened state is good. An electric motor, a drive switch for driving the electric motor, a switch operating member for operating the drive switch, comprising a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism and a clutch mechanism; A clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling driving and stopping of the electric motor, a rotation amount detection means for detecting the rotation amount of the electric motor, and the rotation amount A control unit for detecting and recording a rotation amount (detection value) of an electric motor that rotates a driver bit from a start point of screw tightening by the clutch mechanism to a clutch operation point upon completion of screw tightening by a detection unit. And using a screw tightening device as an electric screwdriver provided respectively,
At the time of screw tightening operation, the control unit compares the rotation amount (detection value) of the electric motor detected as the screw tightening state with the rotation amount (reference value) set in advance and its allowable range and determines whether it is acceptable or not. In the screw tightening pass / fail judgment system configured to perform
Means for comparing the rotation amount (detection value) in the screw tightening state detected in the screw tightening operation with the initially set rotation amount (reference value) and its allowable range, and performing pass / fail judgment;
The quality determination of the result of the case wherein the detection value is departing from the allowable range of the reference value and its, temporarily changes the setting of the allowable range of the pre-expanding the allowable range of the reference value, the detection value And a means for making a pass / fail judgment again. A screw tightened pass / fail judgment system, comprising: An electric motor, a drive switch for driving the electric motor, a switch operating member for operating the drive switch, comprising a driver bit coupled to a drive output shaft of the electric motor via a speed reduction mechanism and a clutch mechanism; A clutch operation detection sensor for detecting the clutch operation of the clutch mechanism, an electric motor control circuit for controlling driving and stopping of the electric motor, and a load torque (reaction force) applied to the driver bit in the electric motor control circuit The load current detecting means for detecting the load current obtained in the electric motor based on the above), and the screw tightening of the electric motor from the start time of screw tightening by the clutch mechanism to the clutch operation time when the screw tightening is completed by the load current detecting means The load current value proportional to the torque value is changed to the load current value ( And a control unit that detects recording as detection value), while using the screwing apparatus as an electric screwdriver provided respectively,
In screw tightening operation, the load current value ( detected value ) of the electric motor detected as the screw tightened state in the control unit is compared with the load current value ( reference value ) set in advance and its allowable range, and the quality is determined. In a screw tightening pass / fail judgment system configured to make a judgment ,
Means for comparing the load current value ( detected value ) of the screw tightening state detected in the screw tightening operation with the initially set load current value ( reference value ) and its allowable range,
The quality of the determination result, if the detection value is departing from the allowable range of the reference value and its, temporarily changes the setting of the allowable range of the pre-expanding the allowable range of the reference value, again of the detection value quality determination system screwing state to the means for performing a quality determination of characterized by having the configuration in which a.

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