JP2013198964A - Automatic screw fastening device, and fastening control method by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastening device and a control method by the same that can perform efficient fastening operation by preventing the total fastening time itself from being extended while having a reaction force reducing effect by intermittent drive, and also, can reduce burden of an operator due to generation of a reaction force.SOLUTION: A torque detection value or a toque output value during a time period in which rotative power is continuously imparted is time-integrated. An amount of work of an impulse is recognized, this amount being a product of: an acting time of a torque continuously acting on a wrench or a torque making the wrench act when the rotative power is continuously imparted; and one of these torques. Based on this recognized amount of work of the pulse, a target screw is controlled to be intermittently fastened by alternately repeating the imparting and temporary stop of the rotative power.

Description

  The present invention relates to an automatic screw tightening device that performs tightening of a screw structure with bolts and screws by forced power and a control method thereof.

  Conventionally, various control means are employed for a power-type screw tightening device that tightens a bolt or a screw with a predetermined torque. For example, as a control method for an impact-type screw tightening device using an electric motor as a rotational drive source, the torque supplied to the load by rotating the motor intermittently by supplying current to the motor is pulsed on the time axis. As described above, a device is disclosed in which the current of each pulse-like current is controlled so as to rotationally drive the motor (see Patent Document 1). In this control, continuous tightening is performed until the tightening torque reaches the seating torque TS. When the tightening torque reaches TS, it is determined that the screw is seated, and the mode is switched to the pulse mode. If the TQM is reached, the target torque of the next pulse is increased.

  Conventionally, during the operation of the main body, the posture change detection means for detecting the change in the posture of the tool main body from the operation start position due to the reaction force generated by the rotation of the output shaft, and the detection signal acquired by the posture change detection means In response, there is disclosed a tightening tool with a built-in angle sensor provided with a drive control means for stopping the operation of the tool when the change in the posture of the tool body becomes a predetermined value or more (see Patent Document 2). This includes a built-in angle sensor that detects a rotation angle with respect to the operation start position of the tool body as a means for detecting a change in posture, and an acceleration that detects an acceleration at which the tool body rotates as a means for detecting an impact force. Built-in sensor. During the tightening operation, when the deflection angle or impact force reaches a preset threshold, the operation of the tool is temporarily stopped, and then the tool is restarted when the tool reaches a preset restart threshold. That's it.

Japanese Patent Laid-Open No. 2002-1676 JP 2005-144625 A

  However, in the former method of controlling the screw tightening device, the amount of increase in the tightening torque until the final target torque is reached is constant, and the ON / OFF repetition time is also a predetermined constant value. For this reason, even if there is an effect of reducing the reaction force by pulse driving, shortening the ON time of pulse driving and increasing the number of repetitions to suppress the reaction force will increase the total tightening time itself, There was a problem that the work became inefficient. In particular, the on / off control is repeated every predetermined time, and the longer the total torque tightening work is performed, the more the reaction force is suppressed during the high torque on operation time.

  In addition, the latter angle sensor built-in tool operates according to the pendulum-like operation posture of the tool based on the generation of the reaction force, that is, the magnitude of the swing width, and the burden on the operator due to the generation of the reaction force is still large. It was.

  Therefore, the present invention prevents the total tightening time itself from being prolonged while having an effect of reducing the reaction force due to intermittent driving, and can perform an efficient tightening operation. It is an object of the present invention to provide a tightening device or a control method thereof that can reduce the burden.

  In order to achieve the above object, the present invention takes the following means (1) to (5).

(1) The automatic screw fastening device of the present invention comprises:
A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power application mechanism that intermittently applies rotational power to the wrench, and a control unit that controls intermittent timing of power application by the power application mechanism; An automatic screw fastening device comprising a fastening tool comprising:
The control means integrates the detected value or output value of the torque during the continuous application of the rotational power over time, and the action of the tightening torque by the torque that continuously acts on the wrench or the torque that acts on the wrench when the rotational power is continuously applied. Recognizing the impulse work that is a time product, and controlling the target screw to be intermittently tightened by alternately repeating the application of rotational power and the temporary stop based on the recognized impulse work It is characterized by.

  As described above, the intermittent tightening is controlled based on the recognized value of the impulse work by continuously applying the rotational power, whereby the tightening control is performed by a relatively simple control algorithm. The value of the recognized work load is related to the tightening force and the tightening time at each tightening stage in intermittent tightening. That is, since the tightening force is relatively small immediately after sitting, the tightening time of each step is automatically adjusted so that the tightening time of each step is relatively long by controlling based on the amount of hard work, and an efficient tightening step is achieved. It will pass. Also, since the tightening force becomes relatively large immediately before the end of tightening, the tightening time of each stage is automatically adjusted so that the tightening time at each stage is relatively short by controlling based on the calculation value of the impulse work. It will prevent the generation of force. The above means corresponds to all the embodiments described later, and also includes other control forms relating to how to detect or set the struggle work amount.

(2) The automatic screw fastening device of the present invention comprises:
A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power applying mechanism that applies rotational power to the wrench, and the wrench and the power applying mechanism, and acts on the wrench when rotational power is applied. A tightening tool comprising a torque sensor for continuously detecting torque and a control means for controlling the timing of power application by the power application mechanism, and a “final target torque” at the end of tightening of at least one workpiece, start / restart of tightening Each of the “work load” from time and “restart timing” for restarting each tightening stage in intermittent tightening (for example, “temporary stop time of rotational power” or “cycle” for restarting each tightening stage) An automatic screw fastening device comprising a setting means for setting a set value,
The control means includes
An application step of starting the application of the rotational power and calculating the impulse work that is the working time product of the tightening force by integrating the detected value of the torque during the application of the rotational power by the torque sensor from the start of the application, and
When the calculated value of the impulse work from the start of application immediately before the rotational power reaches the set value of the “impulse work”, a pause step for temporarily stopping the continuous application of the rotational power;
The application of the rotational power is resumed after the time interval (“temporary suspension time of the rotational power” or “cycle”) by the set value of the “restart timing” has elapsed, and the rotational power is being applied by the torque sensor from the restart point. A re-applying step of calculating the impulse work amount, which is the working time product of the tightening force by integrating the detected torque value over time, and then repeating the pause step and the re-applying step alternately. When the torque detected by the torque sensor reaches the set value of the “final target torque”, the application of rotational power is stopped and the work for tightening the target screw is completed. It is characterized by doing.

  As described above, by controlling each tightening stage in intermittent tightening based on the impulse work of the detected torque during power application in the tightening stage, the tightening torque that is actually generated in each tightening stage is controlled. Automatically adjusted based on. That is, since the detected torque is relatively small immediately after the seating, the application / re-application step for a relatively long time is automatically performed until the setting value of the impulse work is reached. On the other hand, since the detected torque becomes relatively large in the latter stage of tightening immediately before the end of the work, a relatively short re-applying step is automatically performed until the setting value of the impulse work is reached. Thereby, an efficient and safe intermittent tightening work can be reliably executed based on the actual detected torque value. The above means corresponds to Examples 1 and 2 described later.

(3) Or the automatic screw tightening device of the present invention comprises:
A wrench that is fitted to the target screw and can be rotated around the screw shaft, a power application mechanism that applies rotational power to the wrench, and a control that controls the output amount of torque of the rotational power and the timing of power application by the power application mechanism Means, a “final target torque” at the end of tightening of at least one workpiece, an “active work amount” from the start / restart of tightening, an “intermittent number” in intermittent tightening (of one workpiece) “Total number of tightening stages” or “Number of pauses”) and “Restart timing” for restarting each tightening stage in intermittent tightening (for example, “Temporary power suspension time” or “Cycle” for restarting each tightening stage) ), An automatic screw fastening device comprising setting means for setting each setting value of
The control means includes
From the set “final target torque” and the set “intermittent number of times”, the “target torque for each tightening stage” in the intermittent tightening application / reapplying step is automatically set.
Further, from the automatically set “target torque of each tightening stage” and the “set work force”, the “rotation power application time of each tightening stage” that is the time required for the tightening stage of each tightening stage ( Rotation power application time) is automatically set,
Each of the tightening stages in intermittent tightening is sequentially driven as the application / re-application step by the automatically set “rotational power application time of each tightening stage” with the automatically set “target torque of each tightening stage”, By stopping the “rotational power stop time” or “cycle” according to the set “restart timing” and then entering the re-applying step of the next tightening step, re-applying the tightening power of each tightening step. While repeating the application step, control to intermittently tighten the target screw,
When the final target torque is reached, the application of rotational power is stopped, and one work of tightening the target screw is completed.

That is, the control means first controls “target torque at each tightening stage” in intermittent tightening and “rotation power application time at each tightening stage” required for each applying / re-applying step based on each set value. The following steps are performed from the start of one work of tightening.
Each step is
An application step for applying the rotational power while controlling the rotational power so as to be the “target torque for each tightening stage” in the corresponding tightening stage corresponding to the tightening stage;
Rotational power when the elapsed time from the start of the relevant tightening stage (at the start of the most recent rotation power application) reaches the “rotation power application time of each tightening stage”, which is the tightening time in each tightening stage. A pause step for pausing the continuous grant of
After the set value by the “restart timing” has elapsed (“after the temporary suspension time of the rotating power has elapsed since the previous temporary suspension point” or “after the period equivalent to the period since the start of the previous tightening stage”) And a re-applying step of applying the rotational power while controlling the rotational power so that it becomes the “target torque for each tightening step”.
Intermittent tightening performs the application step, the pause step and the re-application step in order,
Thereafter, the pause step and the re-grant step are repeated alternately.
Also,
When the torque output value due to the continuous application of rotational power reaches the set value of the “final target torque”, the rotational power application is stopped, and the repetition of the temporary stop step and the re-applying step is completed.

  As described above, the target torque for each tightening stage in intermittent tightening and the duration of each tightening stage are automatically set in advance, and the output torque is output for each tightening stage based on this automatic setting. By doing so, intermittent tightening is efficiently performed. Here, the “target torque at each tightening stage” according to the automatic setting is automatically set according to a predetermined argument law or calculation law based on the set final target torque and the number of intermittent cycles. Further, the “duration time of each tightening stage” related to the automatic setting is calculated and automatically set by the set impulse work amount and the automatically set target torque. The duration for this automatic setting is automatically set for a relatively long time until reaching the set value of the impulse work because the tightening output torque is relatively small immediately after the seating. On the other hand, since the tightening output torque becomes relatively large in the latter half of the tightening immediately before the end of the work, it is automatically set in a relatively short time. Thereby, an efficient and safe intermittent tightening work can be reliably executed based on the output torque. The above means corresponds to Examples 3 and 4 described later.

(4) Further, the tightening control method by the automatic screw tightening device of the present invention includes:
A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power applying mechanism that applies rotational power to the wrench, and the wrench and the power applying mechanism, and acts on the wrench when rotational power is applied. A tightening tool comprising a torque sensor for continuously detecting torque and a control means for controlling the timing of power application by the power application mechanism, and a “final target torque” at the end of tightening of at least one workpiece, start / restart of tightening Each of the “work load” from time and “restart timing” for restarting each tightening stage in intermittent tightening (for example, “temporary stop time of rotational power” or “cycle” for restarting each tightening stage) A setting means for setting a set value, and a tightening control method by an automatic screw tightening device comprising:
A setting step of setting the set values of the “final target torque”, “improvement work amount”, and “resume timing” in the setting means by external input or by reading from a storage area stored in advance; ,
An application step of starting the application of the rotational power and calculating the impulse work, which is the working time product of the tightening force, by integrating (time) the detected value of the torque being applied by the torque sensor from the application start time. When,
When the calculated value of the impulse work from the start of application immediately before the rotational power reaches the set value of the “impulse work”, a pause step for temporarily stopping the continuous application of the rotational power;
After the elapse of a time interval according to the set value of the “restart timing” (“after the lapse of the temporary stop time of the rotating power from the start of the immediately preceding temporary stop step” or “after the elapse of a period equivalent to the period from the start of the immediately preceding tightening stage)” A re-applying step for resuming the application of the rotational power and calculating an impulse work that is a working time product of the tightening force by time-integrating the detected value of the torque during the application of the rotational power by the torque sensor from the restart point; , In order,
Thereafter, the pause step and the re-grant step are repeated alternately, and then
When the torque output value due to the continuous application of rotational power reaches the set value of the “final target torque”, a stop step for stopping the rotational power application is performed, and one work of tightening the target screw is completed. To do.

  Thereby, an efficient and safe intermittent tightening work can be reliably executed based on the actual detected torque value. The above control method corresponds to Examples 1 and 2 described later.

(5) Or the tightening control method by the automatic screw tightening device of the present invention is:
A wrench that is fitted to the target screw and can be rotated around the screw shaft, a power application mechanism that applies rotational power to the wrench, and a control that controls the output amount of torque of the rotational power and the timing of power application by the power application mechanism Means, a “final target torque” at the end of tightening of at least one work, a “work load” from start / restart of tightening, an “intermittent number” in intermittent tightening (“ "Total number of tightening stages" or "Number of pauses") and "Restart timing" for restarting each tightening stage in intermittent tightening (for example, "Turning time for rotational power" or "Cycle" for restarting each tightening stage) A tightening control method using an automatic screw tightening device configured with setting means for setting each set value of
Each setting value of the “final target torque”, “improvement work amount”, “intermittent number of times”, and “resume timing” is input to the setting means by external input or by reading from a storage area stored in advance. A setting step to set;
From the set “final target torque” and the set “intermittent number”, the control means automatically sets the target torque of the application / re-apply step of each tightening stage in the intermittent tightening, and each of the automatically set An automatic setting step of automatically setting a tightening stage time (rotation power application time of the applying / re-applying step) of each tightening stage from the target torque of the tightening stage and the set “work load”;
Each tightening stage in intermittent tightening is sequentially driven by the automatically set “rotation power application time of each tightening stage” with the automatically set “target torque of each tightening stage”, and the set “restart timing” By entering the next tightening stage according to the above, it is controlled to intermittently tighten the target screw while repeating the reapplying step of the tightening power of each tightening stage,
When the final target torque is reached, the rotational power application is stopped and the tightening of the target screw is completed.

Specifically, after the automatic setting step, an application step of applying the rotational power while controlling the rotational power so as to be "target torque of each tightening stage" in the corresponding tightening stage corresponding to the tightening stage;
Rotating when the elapsed time from the start of the corresponding tightening stage (at the start of the most recent rotation power application) reaches the “rotation power application time of each tightening stage”, which is the tightening stage time in the tightening stage. A pausing step for pausing continuation of power;
After the set value by the “restart timing” has elapsed (“after the temporary suspension time of the rotating power has elapsed since the previous temporary suspension point” or “after the period equivalent to the period since the start of the previous tightening stage”) Re-applying step to apply while controlling the rotational power to become "target torque of each tightening stage" in the stage,
Thereafter, the pause step and the re-grant step are repeated alternately, and then
When the torque output value due to the continuous application of rotational power reaches the set value of the “final target torque”, the rotational power application is stopped, and a stop step is completed to complete the repetition of the temporary stop step and the re-apply step. Complete one work of tightening.
Thereby, an efficient and safe intermittent tightening work can be reliably executed by a simple control method based on the output torque. The above control method corresponds to Examples 3 and 4 described later.

  By taking the above measures, while having the effect of reducing the reaction force due to intermittent tightening drive, it is possible to prevent the total tightening time itself in one work from becoming long, and to perform efficient tightening work. Thus, the present invention provides a tightening device or a control method thereof that can reduce the burden on the operator due to the generation of reaction force.

FIG. 3 is a half cross-sectional view of a tightening tool in the automatic screw tightening device according to the first embodiment. FIG. 3 is an external view of an operation surface of a controller in the automatic screw fastening device according to the first embodiment. 5 is a flowchart of a control method by the automatic screw tightening device according to the first embodiment. 10 is a flowchart of a control method by the automatic screw fastening device of the second embodiment. 3 is a graph showing a detected torque in one work by the tightening device of Example 1. FIG. Explanatory drawing of the graph of the A section of FIG. 5 which shows the detected torque in the one fastening stage. 10 is a graph showing a detected torque in one work by the tightening device of Example 2. 10 is a graph showing output torque during one work by the tightening device of Example 3. The graph which shows the torque conditions of a 1st joint. 3 is a graph showing a detected torque in one work to the first joint by the tightening device of Example 1. FIG. The graph which shows the torque conditions of a 2nd joint. The graph which shows the detected torque in one workpiece | work to the 2nd joint by the clamping device of Example 1. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out the present invention will be described below with reference to the drawings shown as examples. In any embodiment, the automatic screw fastening device of the present invention is basically
A wrench 11 fitted to the target screw and rotatable around the screw shaft; a power applying mechanism 2 that applies rotational power to the wrench 11; and a control means that controls the timing of applying rotational power by the power applying mechanism 2. And a setting means for setting a set value including an impulse work amount of the work amount in at least intermittent tightening.

  The control by the control means basically controls the rotational power so that the tightening target is tightened stepwise and intermittently from the start of tightening until the tightening target becomes the input value of the final target torque. From the start to the end of one work, the rotation power is repeatedly applied / reapplied and paused. When one workpiece is tightened by intermittent tightening, continuous torques are generated in a plurality of tightening stages with pause times as shown in FIGS. 5, 7, 9b, and 10b, respectively.

  Then, the control means integrates the value of the torque during the continuous application of the rotational power (either the continuous detection torque (actual torque) by the torque sensor or the continuous output torque by the power application mechanism 2). By recognizing the impulse work, which is the working time product of the tightening force, and repeatedly applying the rotational power and temporarily stopping based on this impulse work and the setting value of the impulse work The target screw is controlled to be intermittently tightened.

  The set value of the impulse work amount, which is the product of the continuous action time of the tightening force in each tightening stage, is controlled as a constant value or a plurality of variable values for the entire work. For example, in each of the embodiments described later, the active work amount of each tightening stage in one whole work is controlled so as to be always a constant set value, but in addition, one or a plurality of tightening stages in one whole work. You may control as a variable value which changes for every. In the case of controlling the amount of impulse work at each tightening stage as a variable value, for example, from the seating torque when the tightening target is seated to the entire target workpiece until the tightening target becomes the input numerical value of the final target torque, At each of the multiple tightening stages, each of the intensive work is different so that at least the first half of the time from the start of tightening is the first set value and the second half of the time until the final target torque at which tightening ends is the second set value. You may make it become quantity.

  As shown in FIG. 6, in one of the plurality of tightening stages constituting the intermittent tightening, the tightening torque (actual) is continuously applied from the start of the application of the rotational power by the motor drive to the stop of the rotational power by the stop of the drive. Torque) is generated. In the present invention, the time integral value of the torque value (continuous detection torque (actual torque) by the torque sensor) during the continuous application of the rotational power corresponds to the area of FIG.

(Setting method)
As one form of the setting means, an external input means 7 for externally inputting a predetermined parameter value may be provided. In an embodiment to be described later, a remote control type external input means as shown in FIG. 2 is connected by wire, and a control parameter is given to the control means by an input signal from the external input means. Examples of the parameter value to be input include a “final target torque” value that determines a torque at the end of tightening of one workpiece and an “impulse” value that serves as a reference for the intermittent tightening amount. In addition, the value (the rotation power application stop time, the period of the start timing of each stage, or the number of intermittent tightening times) serving as a reference for the timing of stopping or restarting each tightening stage in intermittent tightening can be mentioned.

And in any embodiment, the control method by the automatic screw fastening device of the present invention is basically:
Setting step for setting each setting value including at least “final target torque”, “improvement work amount”, and “resume timing” in the setting means by external input or by reading from a storage area stored in advance When,
Rotational power application is started, and a detected value of torque (or output torque of the rotational power) during the application of the rotational power by the torque sensor is integrated over time from the application start time, and a predetermined working time product of tightening force An imparting step of imparting while controlling the rotational power so as to give an impulse work;
When the impulse work from the start of each tightening stage reaches the set value of the “impulse work” (or the “rotation power application time for each tightening stage” set at that stage has been reached. A pause step to pause the continuous application of rotational power,
The rotation power application is resumed after the set value by the “restart timing” has elapsed, and the detected value (or output torque of the rotation power) of the torque being applied by the torque sensor is integrated over time from the restart point. And re-applying step of re-applying while controlling the rotational power so as to give the impulse work which is the working time product of the tightening force,
Thereafter, the pause step and the re-grant step are repeated alternately, and then
When the detected torque value or the output torque of the rotating power reaches the set value of the “final target torque”, the rotating power application is stopped and the repetition of the temporary stop step and the re-applying step is completed. A stop step is performed to complete one work of tightening the target screw. Hereinafter, the configuration and control contents of each embodiment will be described in detail.

  The automatic screw fastening device according to the first embodiment shown in FIGS. 1 to 3, 5, and 6 is fitted to a target screw and can rotate around a screw shaft, and applies rotational power to the wrench 11. A torque sensor that is provided between the power application mechanism 2, the wrench 11 and the power application mechanism 2, and continuously detects the torque acting on the wrench when the rotational power is applied, and a control means for controlling the timing of power application by the power application mechanism. And a “final target torque” at the end of tightening of at least one workpiece, and “amount of work to be performed from the start / restart of tightening” ”And a controller that is a setting means for setting each set value of“ temporary stop time of rotational power ”that is a“ restart timing ”value for restarting each tightening stage in intermittent tightening. Composed of Ra (FIG. 2). The tightening tool or the controller is operated by the display means 5 (display unit 51, liquid crystal display unit 52, lamp display unit 53) or the operation state is displayed.

(Tightening tool)
Specifically, as shown in FIG. 1, the tightening tool of Embodiment 1 is provided with an angle head portion 1 bent at a right angle at the distal end portion of a cylindrical main body in which a handle portion and a power applying mechanism are coaxially connected. It will be. A cable is connected to the base end of the main body, and is connected to the power source and the external input means shown in FIG. In the angle head unit 1, a wrench 11 that can be connected to the screw head protrudes from the tip of a rotation mechanism built in the head cover. The power applying mechanism 2 includes a gear portion 21 that is coaxially incorporated at the tip of the motor portion 22 via the motor portion 22 and the torque sensor portion 31, and the angle head portion 1 is connected and fixed to the front side of the gear portion 21. The torque sensor unit 31 detects a tightening reaction force, and based on the detected reaction force, the drive of the motor unit 22 (power application timing and power (output torque) magnitude) is controlled by control means (not shown). To do. The handle portion 4 is coaxially connected via a short cylindrical display portion 51 on the proximal end side of the motor portion 22. The display unit 51 incorporated in the tool incorporates a lamp display unit and a buzzer. In addition, a movable throttle lever 32 is incorporated at a position closer to the front side of the handle portion 4, and switching of tightening start / stop (forced stop) of one work is performed according to the movement position of the throttle lever 32.

(Torque sensor)
The tightening tool includes a torque sensor that detects torque based on a tightening reaction force received by the wrench during tightening between the wrench and the power application mechanism.

(controller)
As shown in FIG. 2, the controller of the first embodiment includes an operation key 7 for externally inputting at least the final target torque and the number of tightening steps, a plurality of lamp display units 53, and a liquid crystal display unit 52. The operation key 7 includes a cross key and a numeric keypad, and various setting values can be input by an operation input from the outside. The input set value can be displayed on the liquid crystal display unit 52, and the operation state can be displayed on the lamp display unit 53.

  The control means has at least the first half of the total tightening time from the start of tightening until the tightening target becomes the input numerical value of the final target torque at each tightening stage. The torque may be set so as to be constant in a plurality of tightening stages of either the majority time or the latter half time.

(Control of Example 1)
As shown in the input example in Table 1, the control means of the first embodiment performs the “final target torque” at the end of tightening of one workpiece (“target torque” in the table) and the “impulse” from the start / restart of tightening. “Work load” (“impulse” in the table) and “restart timing” for restarting each tightening step in intermittent tightening, “pause time of rotational power” between each tightening step (“ The set value consisting of the rotation power stop time “)” is input from the external input means, and has a storage area for storing these set values externally input from the external input means. Then, based on the “striking work amount” (“impulse” setting value in the table) among the stored setting values, the tightening work amount of each of the plurality of tightening stages is automatically controlled, and the stored settings The temporary stop time of each tightening stage interval is controlled based on the “rotary power stop time” of the values (the “rotary power stop time” setting value in the table). Further, the end point of the tightening stage is controlled based on the “final target torque” (“target torque” set value in the table) among the stored set values.

  The “rotational power temporary stop time” (“rotational power stop time” in the table), which is the restart timing value of the first embodiment, is always set with a constant rotational power stop time set. This is based on the idea that a slight change in the position of the tool due to the reaction force generated when the rotational power is applied is absorbed by the support of the operator when the rotational power is stopped.

  After the input and storage of the set values are completed, control is performed according to the flow shown in FIG. First, with the start of continuous application of rotational power accompanying the movement of the throttle lever 32, the torque sensor unit 31 determines whether or not the actual torque has reached a preset final target torque. When the value of the torque detected by the torque sensor (actual torque) does not reach the final target torque, the rotational power is continuously applied, and the actual torque detected value by the torque sensor is integrated over time from the start of continuous application of the rotational power. Then, the process proceeds to an application step of calculating a work load that is a working time product of the tightening force. This granting step shall end when the calculated value of the impulse work from the start of applying immediately before the rotational power reaches the set value of the “impulse work”, and with the end of the granting step, The process proceeds to a temporary stop step for temporarily stopping the continuous application of rotational power.

  Then, the time of the temporary stop is measured from the time of transition to the temporary stop step, and when the temporary stop time reaches the “temporary stop time of the rotational power”, the application of the rotational power is resumed. Along with the resumption of the application of the rotational power, the torque sensor unit 31 determines whether or not the actual torque has reached a preset final target torque. If the value of the torque detected by the torque sensor (actual torque) does not reach the final target torque, the application of the resumed rotational power is continued and the actual torque produced by the torque sensor from the start of the continued application of the resumed rotational power. The detected value is integrated over time, and the process proceeds to a re-applying step for calculating the impulse work, which is the working time product of the tightening force. This re-granting step ends when the calculated value of the impulse work from the start of application immediately before the rotational power reaches the set value of the “impulse work”, and the re-grant step ends. At the same time, the process proceeds to a pause step for temporarily stopping the continuous application of the rotational power. Thereafter, the re-applying step and the temporary stopping step are alternately repeated until the detected value of the actual torque by the torque sensor reaches the set value of the “final target torque”.

  During the start of the re-applying step, when the detected value of the actual torque by the torque sensor unit 31 reaches the set value of the “final target torque”, a stop step for stopping the application of the rotational power is performed, and one work is completed. An acceptance / rejection determination display indicating that the operation has been performed is performed by a lighting display on the lamp display unit 53 serving as a display unit, and one work of tightening the target screw is completed.

  In the time axis graph of the actual torque according to the control device and the control content of the first embodiment, for example, as shown in FIG. 5, a torque generation region based on continuous application by a plurality of tightening stages repeatedly appears with a certain pause time interval. . The time integral of the actual torque, that is, the impulse work at each tightening stage based on the detected torque is expressed as the area of each closed region of FIG. 5 or one region of FIG. 6 which is a partially enlarged view thereof. In the first embodiment, the impulse work is set to be the same as the direct external input set value, and the set values of the impulse work for all of the plurality of tightening stages in one work are kept constant. Each area shown in FIG. In this way, if the impulse work at each tightening stage is progressed in a constant or almost constant interval, the detected torque at the time of tightening is relatively small in the initial tightening stage. Application time) is relatively long, which can increase the rotation angle and improve the time efficiency of tightening. In addition, in a tightening work with a constant load increase rate as shown in FIG. 9a, as shown in FIGS. The time (continuous application time of rotational power) is shortened with each step, thereby reducing the load on the worker due to the reaction force during tightening and improving the safety of the tightening operation. In this way, by controlling the tightening amount at each tightening stage using the relatively simple control concept of the active work amount, the efficiency of the tightening time and the improvement in safety can be achieved at the same time.

  On the other hand, in the case of a second workpiece such as a tapping screw as shown in FIG. 10a that once decreases after the tightening torque is increased in one workpiece and then increases, as shown in FIG. The shortening of the tightening stage time as described above proceeds in the ascending section, and thereafter, each stage time is automatically adjusted according to the increase / decrease of the torque detection value at each tightening stage.

  The rotation power stop time of the second embodiment uses the intermittent drive cycle as a set value. In this case, since the period of intermittent driving is made constant, the rotation power stop time becomes shorter as the rotation power application time becomes longer. This is based on the idea that the slight change in the position of the tool due to the reaction force generated when the rotational power is applied is absorbed by the support of the operator in the same way when the rotational power is applied and when the rotational power is stopped.

(Control of Example 2)
As shown in Table 2, the control means of the second embodiment shown in FIG. 6 has a “final target torque” (“target torque” in the table) at the end of tightening of one workpiece, and from the start / restart of tightening. “Rotation power start timing” that specifies the start interval of each tightening stage as the value of “working load” of (in “table” in the table) and “restart timing” for restarting each tightening stage in intermittent tightening ”Cycle” (“cycle” in the table) is input from the external input means and has a storage area for storing these set values externally input from the external input means. Yes. Then, based on the “striking work amount” (the set value of “impulse” in the table) among the stored setting values, the tightening work amount of each of the plurality of tightening stages is automatically controlled, and each stored The start time interval of each tightening stage is controlled on the basis of “rotation power start timing period” (set value of “cycle” in the table) among the set values. Further, the end point of the tightening stage is controlled based on the “final target torque” (the set value of “target torque” in the table) among the stored set values.

  After the input and storage of the set values are completed, the control is performed according to a flow substantially similar to that shown in FIG. However, in the re-granting step, instead of measuring the time of the pause from the time of transition to the pause step, measure the time interval from the start of the immediately preceding tightening phase to the start of the next tightening phase, When the elapsed time from the previous tightening stage reaches the “rotational power cycle”, the application of the rotational power is resumed.

  As in the first embodiment, the torque sensor unit 31 determines whether or not the actual torque has reached a preset final target torque as the rotational power is restarted. If the value of the torque detected by the torque sensor (actual torque) does not reach the final target torque, the application of the resumed rotational power is continued and the actual torque produced by the torque sensor from the start of the continued application of the resumed rotational power. The detected value is integrated over time, and the process proceeds to a re-applying step for calculating the impulse work, which is the working time product of the tightening force. Thereafter, the re-applying step and the pause step are alternately repeated until the detected value of the actual torque by the torque sensor reaches the set value of the “final target torque”. When the detected value of the actual torque by the unit 31 reaches the set value of the “final target torque”, a stop step for stopping the application of rotational power is performed, and a pass / fail judgment display indicating that one work is completed is displayed. This is the same as that of the first embodiment except for the measurement method of the restart timing by the re-applying step until the completion of one work of tightening the target screw while performing the lighting display on the lamp display portion 53.

  The time axis graph of the actual torque according to the control device and the control content of the second embodiment is, for example, as shown in FIG. It appears repeatedly. The configuration and control contents not specifically mentioned are the same as those in the first embodiment.

  The automatic screw fastening device according to the third embodiment includes a wrench that is fitted to a target screw and that can rotate around the screw shaft, a power application mechanism that applies rotational power to the wrench, and a torque that is generated by the power application mechanism. A tightening tool including a control means for controlling the amount of force and the timing of power application, and a “final target torque” at the end of tightening of at least one workpiece, “a work load” from the start / restart of tightening, intermittent “Intermittent number of times” in tightening (“total number of tightening stages” or “temporary stop times” for one workpiece) and “temporary stop time of rotational power” for restarting each tightening stage in intermittent tightening (setting for restart timing) Value example), and setting means for setting each setting value. The present embodiment is different from the first and second embodiments in that it does not determine whether or not the setting value of the impulse work amount has reached the set value based on the detected value of actual torque from the torque sensor. That is, in the third embodiment, the motor drive amount by the rotational power applying means 2 is inverter-controlled, and whether or not the impulse work amount has reached the set value is determined based on the output torque value instead of the actual torque. That is, the control means of the third embodiment divides the tightening stage into steps, automatically sets a “target torque” for each step, and torques the motor with an inverter so that the target torque set in each step of the tightening stage is obtained. In addition to the control, torque output during the power application time in that step and stop in the stop step are repeated for a predetermined time, and then tightening is terminated by reaching a preset final target torque.

  The control means of the third embodiment is set so that the working time product (the area of each closed region in FIG. 8) of the tightening force (motor output value) at each tightening stage is constant. By setting the amount of work to be tightened from the initial tightening stage to the late tightening stage to be the same for at least a predetermined period, automatic control is performed so that the tightening time becomes longer in the initial tightening stage when the tightening torque is low. In this way, the elapsed time can be shortened, while the tightening reaction force can be suppressed by automatically controlling the tightening time to be shortened in the later stage of tightening with high tightening torque.

(Control by the control means of Example 3)
Specifically, the control means of the third embodiment, as shown in the input example in Table 3, “final target torque” (“target torque” in the table) at the end of tightening of one workpiece, “impulse work” ("Intensity" in the table), "Intermittent tightening count"("Intermittent tightening count" in the table), and "Rotating power application pause time"("Rotating power application stop time" in the table) It is assumed that the input is set. Then, based on the “improvement work” (set value of “impulse” in the table) among the set values that have been input and stored, the tightening work for each of the plurality of tightening stages is automatically controlled to be tightened. Are divided by the set value of the “intermittent tightening frequency” (“intermittent tightening frequency” in the table) and tightened stepwise and intermittently so that the tightening torque in each step increases in order. The rotational power is controlled until the input value of the target torque is reached (the set value of “target torque” in the table). In addition, the temporary stop time between the tightening stages (“rotation power application stop time” in the table) is a constant value based on the set value by the external input as in the first embodiment, and is a constant time interval between the tightening stages. Is set.

  The control means of the third embodiment is controlled according to FIG. 4 and the flow shown below after the input and storage of the set values are completed. First, based on the input set value from the external input means, the target torque and impulse work amount at each stage are automatically calculated (automatically set) based on an arithmetic expression or an argument stored in advance in the storage area. That is, in the third embodiment, after the setting step of setting each set value by the external input means and storing it in the storage area, the set “final target torque” and the set “interruption count” (number of steps (N)) From the two set values, the target torque of the application / re-application step of each tightening stage in the intermittent tightening is set by automatic calculation, and the target torque of each of the automatically set tightening stages and the set “work load” From the above, it is assumed that an automatic setting step of automatically setting the tightening stage time (rotation power applying time of the applying / re-applying step) of each tightening stage is performed (FIG. 3).

Then, as the applying / re-applying step of each tightening stage in the intermittent tightening, the automatically set tightening stage time is sequentially driven with the automatically set target torque to stop only for the set “rotational power stop time”. After that, a re-applying step of the next tightening stage is entered, and the target screw is controlled to be intermittently tightened while repeating the re-applying step of the tightening power of each tightening stage.
Specifically, the tightening stage of Step N = 1 is started together with the start of tightening of one work accompanying the movement of the throttle lever 32, and it is determined whether or not the tightening torque has reached a preset final target torque. Here, in the third embodiment, it is determined whether or not the torque output value resulting from the continuous application of rotational power has reached a preset final target torque. As in the first embodiment, the actual torque may be detected by the torque sensor unit 31 and determined based on the detected actual torque value.
In Step N = 1, when the torque output value due to the continuous application of the rotational power does not reach the final target torque, the rotational power of Step N = 1 is continuously applied and the output torque of the rotational power is set to “Step N = 1”. The process proceeds to an applying step for controlling the torque to "target torque at". This grant step ends when the elapsed time from the start of the continuous grant reaches the “power grant time at step N = 1”, and with the end of the grant step, the continuous grant of rotational power is temporarily stopped. Move to the pause step.
Then, the time of the temporary stop is measured from the time of transition to this temporary stop step, and when the temporary stop time of the rotational power has elapsed from the previous temporary stop time, the application of rotational power is resumed, and the process proceeds to next step N + 1 To do. With the resumption of the rotational power, that is, the transition to the next step N + 1, it is determined whether or not the tightening torque has reached the preset final target torque.
In the next step N = previous N + 1, the reassignment step and the stop step are similarly repeated.
Thereafter, until the output torque of the torque-controlled motor reaches the set value of the “final target torque”, the re-applying step of the next step N = previous step N + 1 and the pause step for a certain time are alternately repeated. .

During the start of the re-applying step, if the output torque due to the continuous application of rotational power reaches the set value of the “final target torque”, a stop step for stopping the application of rotational power is performed, and one work is completed. Is displayed by turning on the lamp display 53 as a display means, and one work of tightening the target screw is completed.
The time axis graph of the actual torque according to the control device and the control content of the third embodiment is, for example, similar to FIG. 7, the torque generation region based on continuous application by a plurality of tightening stages is repeated with a certain pause time interval. appear. The time integration of torque, that is, the impulse work at each tightening stage by the target torque, is expressed as the area of each closed region in FIG. At this time, as shown in FIG. 8, the output torque in the control of the third embodiment continuously outputs the target torque automatically calculated in each step at each stage. The time of each stage is a value obtained by dividing the value of the set impulse work by this target torque. In the third embodiment, control is performed so that the impulse work amount at each tightening stage is constant in one work. Thereby, the time integral value of the target torque of each tightening step is constant between the respective tightening steps, and the area of the closed section in FIG. 8 is equal in each tightening step.

  As in the third embodiment, the target torque is set for each tightening stage, and the motor is torque-controlled to the target torque set in each tightening stage, so that only the setting of the target torque in each tightening stage and the setting of each stage interval time are performed. Since variable control can be performed relatively easily, the calculation load on the input value is reduced, and the operation stability and the response to the input of the set value are improved.

(Control of Example 4)
As shown in the input example in Table 4, the control means of the fourth embodiment includes a “final target torque” (“target torque” in the table) at the end of tightening of one workpiece, “impulse work” (in the table) “Impulse”), “intermittent tightening count” (“intermittent tightening count” in the table), and “rotational power start timing period” (“period” in the table) are input and set. Then, based on these input set values, the tightening target is divided by the input numerical value of the number of tightening steps, and tightening is performed stepwise and intermittently so that the tightening torque for each step increases in order, and tightening is started. Until the tightening target reaches the input value of the final target torque, the target torque and the tightening stage time for each tightening stage are automatically set to control the rotational power.
In particular, in Example 4, the “restart timing” value at which each tightening stage is restarted in intermittent tightening includes a “rotational power start timing period” (“period” in the table) that defines the start interval of each tightening stage. The set value is input and set from the external input means, and has a storage area for storing these set values externally input from the external input means. Then, based on the “striking work amount” (“impulse” in the table) among the stored setting values, the tightening work amount of each of the plurality of tightening stages is automatically controlled, and the stored setting values are The start time interval of each tightening stage is controlled based on the “period of rotational power start timing” (“period” in the table). Further, the end point of the tightening stage is controlled based on the “final target torque” (“target torque” in the table) among the stored set values.

上記の設定値の入力及び記憶が完了したのちは、図４に示すものとほぼ同様のフローに従って制御される。但し、再付与ステップにおいては、一時停止ステップへの移行時点から当該一時停止の時間を計測するのではなく、直前の締め付け段階の開始時点からの次の締め付け段階開始までの時間間隔を計測し、前回の締め付け段階からの経過時間が前記「回転動力の周期」に到達した時点で、回転動力の付与を再開させる。
そして実施例３と同様、回転動力の付与再開すなわち次ステップＮ＋１への移行とともに、締め付けトルクの、予め設定された最終目標トルクへの到達の有無を判別する。
次ステップＮ＝前回Ｎ＋１において、回転動力の継続付与によるトルク出力値が最終目標トルクに至っていない場合には、再開した回転動力の付与を継続させるとともに、当該再開した回転動力の継続付与開始時点からの経過時間が、「ステップＮ＝前回Ｎ＋１における動力付与時間」に到達した時点で終了するものとし、付与ステップの終了とともに一時停止ステップに移行する。
それ以降、回転動力の出力トルク値が前記「最終目標トルク」の設定値に到達するまで、次ステップＮ＝前回ステップＮ＋１の再付与ステップと、各締め付け段階の開始時点から一定周期の一時停止ステップとを交互に繰り返し、再付与ステップの開始中において、回転動力の継続付与によるトルク出力値が前記「最終目標トルク」の設定値に到達した場合には回転動力の付与を停止させる停止ステップを行ない、一ワークが完了したことを示す合否判定表示を表示手段たるランプ表示部５３への点灯表示によって行なうとともに、対象螺子の締め付けの一ワークを完了するまで、再付与ステップによる再開のタイミングの計測方法以外は、実施例３と同様である。
実施例４の制御装置及び制御内容による実トルクの時間軸グラフは例えば、図７と同様に、複数の各締め付け段階による継続付与に基づくトルク発生領域が、一定の締め付け段階の開始時間間隔をあけて繰り返し表れる。特記しない構成及び制御内容は実施例３と同様である。

After the input and storage of the set values are completed, control is performed according to a flow that is substantially the same as that shown in FIG. However, in the re-granting step, instead of measuring the time of the pause from the time of transition to the pause step, measure the time interval from the start of the immediately preceding tightening phase to the start of the next tightening phase, When the elapsed time from the previous tightening stage reaches the “rotational power cycle”, the application of the rotational power is resumed.
Then, as in the third embodiment, with the restart of the application of the rotational power, that is, the transition to the next step N + 1, it is determined whether or not the tightening torque has reached the preset final target torque.
In the next step N = previous N + 1, when the torque output value due to the continuous application of rotational power does not reach the final target torque, the restarted rotational power is continuously applied and from the start of the continuous application of the restarted rotational power. Is finished when the elapsed time reaches “step N = the power application time in the previous N + 1”, and the process proceeds to the pause step when the application step ends.
Thereafter, until the output torque value of the rotational power reaches the set value of the “final target torque”, the re-applying step of the next step N = previous step N + 1 and the temporary stopping step of a fixed period from the start point of each tightening stage When the torque output value due to the continuous application of rotational power reaches the set value of the “final target torque” during the start of the reapplying step, a stop step is performed to stop the application of the rotational power. A method for measuring the timing of resumption by the re-applying step until the completion of one work of tightening the target screw is performed while a pass / fail judgment display indicating that one work has been completed is displayed on the lamp display unit 53 as a display means. Other than the above, the third embodiment is the same as the third embodiment.
In the time axis graph of the actual torque according to the control device and the control content of the fourth embodiment, for example, similarly to FIG. 7, the torque generation region based on the continuous application by each of the plurality of tightening stages has a constant tightening stage start time interval. Appear repeatedly. The configuration and control contents not specifically mentioned are the same as those in the third embodiment.

(Example of automatic setting of automatic setting step)
Here, an example of automatic calculation in the automatic setting step of the third and fourth embodiments is shown below. Assuming that the final target torque is Tq, the number of intermittent tightening times of one workpiece is N, and the impulse work of the output torque in each tightening stage is Tt, the target torque Tn in each tightening stage (applying step or reapplying step) and tightening The stage time (rotation power application time of each tightening step) tn is calculated by the following expression stored in advance in the storage area.

(Equation 1)
Tn = Tq√ (n / N)

(Equation 2)
tn = Tt / Tn

For example, when Tq = 25 [N · m], N = 10, and Tt = 100 [N · m · ms], the target torque (output torque) of each tightening step of N = 1 to 10 according to the above formulas 1 and 2. ) And the rotational power application time of each tightening step are automatically set as shown in the following table.

上例では、各ステップの目標トルクを最終目標トルクに基づく２次関数式によって算出しているが、二次関数に限らず、指数関数、高次関数等、さまざまな関数で求めることができる。また関数による演算を行わず、最終目標トルク及び断続回数の数値範囲の組み合わせ条件に基づく引数によって、記憶領域に記憶した複数の数値から、各ステップの目標トルクとしてあてはめられるべきいずれかの数値を読みだすものとしてもよい。
この自動設定において、各締め付け段階における締め付けトルクの単位時間当たりの増加量は、外部入力手段からの最終目標トルク及び締め付け段階数の各入力値に基づいて、前段階の締め付けトルクの増加量よりも小さくなるように設定される。締め付けトルクの増加速度が徐々に小さくなることにより、締め付け初期段階における締め付けステップを、比較的大きな締め付けトルクの増加によってこなすことができる。つまり締め付けトルクの初期段階増加を急激なものとすることで、初期締め付け時間を短縮することができる。

In the above example, the target torque of each step is calculated by a quadratic function expression based on the final target torque. However, the target torque is not limited to the quadratic function but can be obtained by various functions such as an exponential function and a high-order function. Also, without any calculation by function, read one of the numerical values that should be applied as the target torque for each step from the multiple numerical values stored in the storage area by an argument based on the combination condition of the numerical range of the final target torque and the number of intermittent cycles. It can also be used.
In this automatic setting, the amount of increase in tightening torque per unit time in each tightening stage is greater than the amount of increase in tightening torque in the previous stage, based on the final target torque from the external input means and the input values of the number of tightening stages. It is set to be smaller. By gradually decreasing the increasing speed of the tightening torque, the tightening step in the initial stage of tightening can be performed by increasing the relatively large tightening torque. That is, the initial tightening time can be shortened by making the initial stage increase of the tightening torque abrupt.

  Also, in the automatic setting, the tightening step at the final stage of tightening is reliably interrupted by a slight increase in tightening torque by variably controlling the tightening torque increase amount gradually by the control means. You can do it. That is, by making the final stage increase in the tightening torque small, it is possible to reliably perform the final tightening and to reliably suppress the reaction force felt by the tightening operator.

  Alternatively, in the above automatic setting, the tightening time in each tightening stage is set so as not to be longer than the previous tightening time based on the final target torque from the external input means and the input values of the number of tightening stages. Also good. By variably controlling the tightening time at each tightening stage to be gradually reduced, the amount of rotation (angular displacement) at each tightening stage is relatively increased and a large number of screw turns is secured at the initial tightening stage. On the other hand, at the final stage of tightening, the amount of rotation (angular movement) at each tightening stage is relatively reduced to reduce the forced runout of the tool due to the reaction force, thereby enabling efficient and reliable screw tightening work. it can.

(Other embodiments)
In addition, the present invention is not limited to the above-described embodiments, and omission or extraction of some configurations, combinations of configurations between embodiments, addition of other configurations, separate members without departing from the spirit of the present invention Various changes are possible, such as a combination of the above, an integrated configuration of different members, a combined configuration of a part of different members, a change in the shape or the overall shape of some constituent materials. More specifically, a modified example of the following form is conceivable.

(Setting means without external input means)
The setting means is not limited to one provided with external input means. For example, as a setting means that does not include an external input means, these are not input and set by an external operation, but one or more preset parameter values are stored in a storage area, and the parameter values are read from the storage area It may be set automatically.

(Set values for multiple hard work)
The control means includes a storage area that stores a plurality of setting values of the impulse work, and reads the setting value of the impulse work of the working time product of the tightening force at each tightening stage from the storage area to set the torque. It is good also as what to do. Specifically, for example, a setting value of one impulse work amount associated based on the input value of the final target torque from the external input unit is read from the storage area, and the read setting value of the impulse work amount is It is preferable to set the target torque in each tightening stage based on the input value of the number of tightening stages from the external input. The value that becomes the target torque at each stage is determined based on one set value of the impulse work read out from the storage area, so that the target torque and the torque addition time based on the impulse work can be controlled. Surely done.

(Constant control of impulse work)
In the automatic screw tightening device, the control means, in each tightening stage, the total work time from the start of tightening until the tightening target becomes the input value of the final target torque from the start of tightening. Among them, the torque may be set to be constant in a plurality of tightening stages at least in either the first half time or the second half time. The control means of each of the embodiments controls the power application time so that the work amount of the working time product of the tightening force is constant at each tightening stage. By setting the amount of work to be tightened from the initial tightening stage to the late tightening stage to be the same for at least a predetermined period, automatic control is performed so that the tightening time becomes longer in the initial tightening stage when the tightening torque is low. In this way, the elapsed time can be shortened, while the tightening reaction force can be suppressed by automatically controlling the tightening time to be shortened in the later stage of tightening with high tightening torque.

(Increase / decrease in hard work)
On the other hand, in the control method of the automatic screw tightening device of the present invention, when the reaction force due to the set work load suddenly acts on the operator as soon as the tightening is started, the burden on the operator is large. In order to avoid this, at the initial stage of tightening, power application is stopped when the impulse work is smaller than the set value, and gradually increases every time intermittent driving is performed to reach the set value. It can be suppressed. In this way, it is possible to perform better intermittent tightening by controlling the increase / decrease of the impulse work from the initial tightening to the late tightening, rather than always having a constant hard work. To do.

(Storage area)
The control means includes a storage area that stores a set value (one or more) of the struggle work, and stores the set value of the tightening work that is the working time product of the tightening force at each tightening stage. It is preferable to perform control so that one tightening work is intermittently tightened in a plurality of tightening stages according to the tightening work amount.

DESCRIPTION OF SYMBOLS 1 Angle head part 11 Wrench 2 Power provision mechanism 21 Gear part 22 Motor part 31 Torque sensor part 32 Throttle lever 4 Handle part 5 Display means 51 Display part 52 Liquid crystal display part 53 Lamp display part 6 Cable

Claims (5)

A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power application mechanism that intermittently applies rotational power to the wrench, and a control unit that controls intermittent timing of power application by the power application mechanism; An automatic screw fastening device comprising a fastening tool comprising:
The control means recognizes an impulse work, which is a working time product of the tightening torque, by integrating the detected value or output value of torque during the continuous application of rotational power, and rotates based on the impulse work. An automatic screw tightening device that controls to intermittently tighten a target screw by alternately repeating power application and temporary stop. A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power applying mechanism that applies rotational power to the wrench, and the wrench and the power applying mechanism, and acts on the wrench when rotational power is applied. A tightening tool comprising a torque sensor for continuously detecting torque and a control means for controlling the timing of power application by the power application mechanism, and a “final target torque” at the end of tightening of at least one workpiece, start / restart of tightening An automatic screw tightening device comprising: setting means for setting each set value of “work load” from time and “restart timing” for restarting each tightening stage in intermittent tightening,
The control means includes
An application step of starting the application of the rotational power and calculating the impulse work that is the working time product of the tightening force by integrating the detected value of the torque during the application of the rotational power by the torque sensor from the start of the application, and
When the calculated value of the impulse work from the start of application immediately before the rotational power reaches the set value of the “impulse work”, a pause step for temporarily stopping the continuous application of the rotational power;
The application of the rotational power is resumed after the elapse of the time interval according to the setting value of the “restart timing”, and the operation time of the tightening force is integrated by time integration of the detected value of torque during the application of the rotational power by the torque sensor from the restart time. A re-granting step for calculating an impulse work that is a product,
Thereafter, intermittent tightening is performed by alternately repeating the pause step and the reapplying step,
An automatic screw fastening device, wherein when a detected value of torque by a torque sensor reaches a set value of the “final target torque”, the application of rotational power is stopped and one work of fastening of the target screw is completed. A wrench that is fitted to the target screw and can be rotated around the screw shaft, a power application mechanism that applies rotational power to the wrench, and a control that controls the output amount of torque of the rotational power and the timing of power application by the power application mechanism A clamping tool having means, and a “final target torque” at the end of tightening of at least one workpiece, an “amount of work” from the start / restart of tightening, an “intermittent number” in intermittent tightening, and intermittent An automatic screw tightening device configured by setting means for setting each set value of `` restart timing '' for resuming each tightening stage in tightening,
The control means includes
From the set "final target torque" and the set "intermittent number", automatically set "target torque at each tightening stage" in intermittent tightening,
Furthermore, from the automatically set “target torque at each tightening stage” and the set “work load”, the “rotational power application time at each tightening stage” that is the time of each tightening stage is automatically set,
Each tightening stage in intermittent tightening is sequentially driven by the automatically set “rotation power application time of each tightening stage” with the automatically set “target torque of each tightening stage”, and the set “restart timing” By entering the next tightening stage according to the above, it is controlled to intermittently tighten the target screw while repeating re-applying the tightening power of each tightening stage,
An automatic screw tightening device that stops the application of rotational power when the final target torque is reached and completes tightening of the target screw. A wrench that is fitted to the target screw and is rotatable around the screw shaft, a power applying mechanism that applies rotational power to the wrench, and the wrench and the power applying mechanism, and acts on the wrench when rotational power is applied. A tightening tool comprising a torque sensor for continuously detecting torque and a control means for controlling the timing of power application by the power application mechanism, and a “final target torque” at the end of tightening of at least one workpiece, start / restart of tightening In a tightening control method by an automatic screw tightening device comprising setting means for setting each set value of “work load” from time and “restart timing” for restarting each tightening stage in intermittent tightening There,
A setting step of setting the set values of the “final target torque”, “improvement work amount”, and “resume timing” in the setting means by external input or by reading from a storage area stored in advance; ,
An application step of starting the application of the rotational power and calculating the impulse work that is the working time product of the tightening force by integrating the detected value of the torque during the application of the rotational power by the torque sensor from the start of the application, and
When the calculated value of the impulse work from the start of application immediately before the rotational power reaches the set value of the “impulse work”, a pause step for temporarily stopping the continuous application of the rotational power;
The application of the rotational power is resumed after the elapse of the time interval according to the setting value of the “restart timing”, and the operation time of the tightening force is integrated by time integration of the detected value of torque during the application of the rotational power by the torque sensor from the restart time. A re-granting step for calculating an impulse work that is a product,
Thereafter, the pause step and the re-grant step are repeated alternately, and then
Tightening control by an automatic screw tightening device that stops the rotation power application and completes the tightening of the target screw when the torque output value due to the continuous application of the rotational power reaches the set value of the “final target torque”. Method. A wrench that is fitted to the target screw and can be rotated around the screw shaft, a power application mechanism that applies rotational power to the wrench, and a control that controls the output amount of torque of the rotational power and the timing of power application by the power application mechanism A clamping tool having means, and a “final target torque” at the end of tightening of at least one workpiece, an “amount of work” from the start / restart of tightening, an “intermittent number” in intermittent tightening, and intermittent tightening A tightening control method by an automatic screw tightening device configured with setting means for setting each set value of `` restart timing '' for resuming each tightening stage in
Each setting value of the “final target torque”, “improvement work amount”, “intermittent number of times”, and “resume timing” is input to the setting means by external input or by reading from a storage area stored in advance. A setting step to set;
The control means automatically sets the “target torque for each tightening stage” in the intermittent tightening from the set “final target torque” and the set “number of intermittent times”, and automatically sets the target for each tightening stage. An automatic setting step for automatically setting a tightening stage time of each tightening stage from the torque and the set “work load”,
Each tightening stage in intermittent tightening is sequentially driven by the automatically set “rotation power application time of each tightening stage” with the automatically set “target torque of each tightening stage”, and the set “restart timing” By entering the next tightening stage according to the above, it is controlled to intermittently tighten the target screw while repeating the reapplying step of the tightening power of each tightening stage,
A tightening control method using an automatic screw tightening device, characterized in that when the final target torque is reached, the application of rotational power is stopped and the tightening of the target screw is completed.

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