JP4188267B2 - Nutrunner and control method thereof - Google Patents

Description

  The present invention relates to a nut runner for tightening a tightening object from a seating torque when a tightening object such as a bolt or a nut is seated to a target torque when the tightening object is completely tightened, and a control method thereof.

  As a method for controlling a nut runner that automatically tightens bolts and nuts onto a workpiece, a torque method is generally used in which the tightening accuracy is evaluated by tightening torque of the bolts and nuts. In this type of nut runner, a socket is provided on the output shaft extending from the nut runner body, the socket is detachably fitted to a bolt or nut, and the nut runner body is attached to the nut runner body based on a control signal from an external controller. By controlling the rotation of the built-in drive motor, the socket is rotated to tighten bolts and nuts. The nut runner body incorporates a torque sensor for detecting the tightening torque in addition to the drive motor.

  In the controller described above, the bolts and nuts are tightened from the seating torque when the bolts and nuts are seated to the target torque when the bolts and nuts are completely tightened. The relationship is shown in FIG. FIG. 8 is a flowchart showing an algorithm in the tightening process by the nut runner.

The nutrunner socket is rotated in a state where it is fitted to a bolt, nut or the like, and the tightening operation is started (STEP 1). From the start of this tightening operation until the bolt, nut, etc. are seated, the nut runner is rotated at a high speed V _S in order to shorten the tightening cycle time (STEP 2). The seating torque T _S at this seating point is preset by the controller.

After starting the tightening operation by the nut runner, the seating torque T _S is detected by the torque sensor (STEP 3), and when the seating torque T _S is reached, the speed V _H is set (STEP 4), and the bolt is set at the speed V _H. Tighten nuts and nuts (STEP 5). Then, it is detected whether or not the preset target torque T _C is reached by the controller (STEP 6), and when the target torque T _C is reached, the tightening operation is stopped (STEP 7).

Then, after determining whether or not various conditions such as torque and rotation angle are within a predetermined allowable range (STEP 8), the tightening process is terminated (STEP 9). Thus, from the seating point to the tightening completion point, the rotational speed is controlled by the controller based on the speed V _H (fixed value) preset by the controller so that the socket rotates constantly (for example, patents) Reference 1).
JP 2000-326250 A

Conventionally, as described above, the seating torque T _S is continuously tightened to the target torque T _C at a constant speed V _H. That is, it is general that the tightening is performed at high speed until the seating torque T _S and then the target torque T _{C is} tightened at a constant speed V _H. When tightening up to the target torque T _C at a constant speed V _H in this way, the reaction force increases in proportion to the tightening torque when a hand-held electric nutrunner is used. And it becomes a physical burden.

Here, as the tightening is slow, because the time required to reach the target torque T _C becomes longer, the time becomes longer consuming reaction force. On the other hand, it is possible to shorten the time required for the reaction force by performing the tightening at a high speed, but there is a possibility that a problem may occur in the accuracy for assuring the tightening quality of the product.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to use a reaction force generated during tightening from the seating torque to the target torque when a hand-held electric nutrunner is used. It is an object of the present invention to provide a nutrunner and a control method thereof.

As a technical means for achieving the above-described object, the nutrunner control method according to the present invention includes a tightening object from a seating torque when the tightening object is seated to a target torque when the tightening object is completely tightened. a method of controlling a nut runner for tightening the goods, the between the seating torque until it reaches the target torque, each to raise the tightening torque at the tightening operation by Shi repeatedly fast clamping operation and slow tightening operation It is characterized by controlling the speed and time in the tightening operation.

The nutrunner according to the present invention is a nutrunner that tightens the object to be tightened from a seating torque when the object to be tightened is seated to a target torque when the object to be tightened is completely tightened. between to reach, and characterized by including a controller for controlling the speed and time in each clamping operation to increase the tightening torque in the tightening operation by repeatedly fast clamping operation and slow tightening operation To do. In addition, this controller can also be comprised as a control apparatus separate from a nut runner other than being incorporated in a nut runner.

In the present invention, between the seating torque until it reaches the target torque, controls the speed and time in each clamping operation to increase the tightening torque in the tightening operation by repeatedly fast clamping operation and slow tightening operation By doing so, when the hand-held electric nutrunner is used, the reaction force generated in proportion to the tightening torque can be dispersed, so that the reaction force can be reduced.

  In the above-described configuration, the speed or time in the high-speed fastening operation can be made constant or variable as the fastening torque increases for each fastening operation. Further, the speed or time in the low-speed tightening operation can be made constant or variable as the tightening torque increases for each tightening operation.

  In this way, the speed or time in the high-speed tightening operation or the speed or time in the low-speed tightening operation is made constant or variable as the torque increases during the tightening process for each tightening operation. Even if the presence or number of inclusions such as washers is changed, the change can be quickly and easily handled.

According to the present invention, between the seating torque until it reaches the target torque, speed and time in each clamping operation to increase the tightening torque in the tightening operation by repeatedly fast clamping operation and slow tightening operation When the handheld electric nutrunner is used, the reaction force generated in proportion to the tightening torque can be reduced, reducing the mental and physical burden on the operator and tightening accuracy. Can ensure the tightening quality of the product and provide a user-friendly nutrunner.

  Hereinafter, a hand-held electric nutrunner will be described in detail as an embodiment of the present invention. As shown in FIG. 2, this hand-held electric nutrunner is provided with a socket 17 at the tip of a nutrunner main body 15 incorporating an amplifier 11, a resolver 12, a servo motor 13, and a torque sensor 14 via a speed reducer 16, and the socket 17 Is detachably fitted to the head of the bolt 18 which is an object to be tightened. As an object to be tightened, a nut can be used in addition to the bolt 18. The amplifier 11 described above controls the servo motor 13 based on the detection signal from the torque sensor 14, and the resolver 12 controls the rotation angle of the servo motor 13. In the figure, 19 is a switch.

  The hand-held electric nutrunner also includes a controller 21 that drives the servo motor 13 based on a control signal to control the rotation of the socket 17 at the distal end of the output shaft. The controller 21 includes a CPU 22, a servo amplifier circuit 23, an I / F circuit 24, and an A / D conversion circuit 25. The servo amplifier circuit 23 controls the servo motor 13 based on a control signal from the CPU 22.

  In the hand-held electric nutrunner of this embodiment, the bolt 18 is tightened by controlling the rotation of the servo motor 13 based on the following control method. FIG. 1 shows an example of the relationship between time, torque and speed in the nutrunner tightening operation, and FIG. 3 shows a flowchart showing an algorithm in the tightening process as shown in FIG.

First, the nutrunner socket is rotated in a state of being fitted to the bolt 18 to start the tightening operation (STEP 1). Here, the counter value n is set to 0 and the counter value is initialized (STEP 2). From the start of this tightening operation until the bolt 18 is seated, the nut runner is rotated at a high speed V _S in order to shorten the tightening cycle time (STEP 3). The seating torque T _S at this seating point is preset by the controller 21.

After starting the tightening operation by the nut runner, the seating torque T _S is detected by the torque sensor 14 (STEP 4). From the time when the seating torque T _S is reached until the time when the target torque T _C is reached and the tightening is completed, the rotation of the servo motor 13 is controlled as follows based on an algorithm preset by the controller 21.

Speed until it reaches the target torque T _C, in the high-speed clamping operation to repeat fast clamping operation and slow tightening operation when the bolt 18 is completed bolt 18 is tightened from the seating torque T _S when seated V _Hn and time t _Hn , and speed V _Ln and time t _Ln in a low-speed fastening operation are controlled.

That is, when the seating torque T _S is reached, the counter value is counted up from n to n + 1 (STEP 5), the speed V _Hn and the time t _Hn in the fast tightening operation are set (STEP 6), and the speed V _The bolt 18 is tightened with _Hn for a time t _Hn (STEP 7). In the tightening process of FIG. 1, the speed V _Hn in the high-speed tightening operation is always kept constant throughout each tightening operation, and the time t _Hn in the high-speed tightening operation is set constant for each tightening operation. ing. Once that the fastening operation is completed to detect whether or not reached the target torque T _C (STEP8), does not reach the target torque T _C, set the speed V _Ln and time t _Ln in the slow tightening operation (STEP 9), the bolt 18 is tightened for the time t _Ln at the speed V _Ln (STEP 10). Once that the fastening operation is completed, to detect whether or not reached the target torque T _C (STEP 11), it does not reach the target torque T _C, fast tightening at a speed V _Hn bolts 18 by time t _Hn The tightening operation and the low-speed tightening operation of tightening the bolt 18 for the time t _Ln at the speed V _Ln are repeated.

The setting of the speed V _Hn and the time t _{Hn in} the above-described high-speed tightening operation (STEP 5) and the setting of the speed V _Ln and the time t _Ln in the low-speed tightening operation (STEP 9) are performed in advance. It may be each time set from _S and the target torque T _C per fastening operation by a predetermined calculation process, otherwise, can be set in advance as the seating torque T _S and the target torque T _C.

Whether the target torque T _C has been reached after high-speed tightening operation of tightening the bolt 18 at the speed V _Hn for the time t _Hn or low-speed tightening operation of tightening the bolt 18 at the speed V _Ln for the time t _Ln . It detects whether (STEP8, STEP11), if it has reached the target torque T _C, stops the clamping operation (STEP 12). Then, after determining whether or not various conditions such as torque and rotation angle are within a predetermined allowable range (STEP 13), the tightening process is terminated (STEP 14).

Thus, the speed V _Hn and the time t _Hn in the high-speed tightening operation and the low-speed tightening operation so that the high-speed tightening operation and the low-speed tightening operation are repeated until the target torque T _C is reached from the seating torque T _S. By controlling the speed V _Ln and the time t _Ln at, the reaction force generated in proportion to the tightening torque can be dispersed, so that the reaction force can be reduced.

In the tightening process of FIG. 1, the speed V _Ln in the low-speed tightening operation is variable as the tightening torque increases with respect to the constant speed V _Hn in the high-speed tightening operation, and the low torque region (n = 1, 2,...), The speed V _Hn in the high-speed tightening operation in a high torque range (n =..., N−1, n) with a small difference from the speed V _Hn in the high-speed tightening operation. And the difference is increased .

Further, the time t _Ln in the low-speed tightening operation is also variable as the tightening torque is increased with respect to the constant time t _Hn in the high-speed tightening operation, and the low torque region (n = 1, 2, small reaction force) is small. ...) reduce the difference between the time t _Hn in fast tightening operation in and large high torque region of the reaction force (n = ..., the difference between time t _Hn in n-1, n) and fast clamping operation Enlarge. Thus, by making the speed V _Ln or the time t _Ln in the low-speed tightening operation automatically variable as the torque increases during the tightening process, the reaction force and impact felt by the operator can be minimized. .

In the tightening process of FIG. 1, the case where the time t _Hn in the high-speed tightening operation is constant for each tightening operation has been described. However, the present invention is not limited to this, and for example, FIGS. The tightening process as shown in FIG.

In the tightening process shown in FIG. 4, the time t _Hn in the fast tightening operation is monotonously increased for each tightening operation as the tightening torque increases. Conversely, in the tightening process shown in FIG. 5, the time t _Hn in the high-speed tightening operation is monotonously decreased for each tightening operation as the tightening torque increases. 4 and 5, the time t _Hn in the high-speed tightening operation is monotonously increased or decreased, but can be irregularly increased or decreased.

1, 4, and 5, the speed V _Ln in the low-speed tightening operation is variable as the tightening torque is increased, and the speed is high in a low torque region (n = 1, 2,...) With a small reaction force. reduce the difference between the speed V _Hn in Do clamping operation, and a large high-torque region of the reaction force (n = ..., n-1 , n) is to increase the difference between the velocity V _Hn in fast tightening operation . The present invention is not limited to this, and conversely, the speed V _Ln in the low-speed tightening operation is changed to the speed V _Hn in the high-speed tightening operation in the low torque region (n = 1, 2,...) With a small reaction force. And a difference from the speed V _Hn in a high-speed tightening operation in a high torque region (n =..., N−1, n) with a large reaction force may be set to be small. Further, the speed V _Ln in the low-speed tightening operation can be made constant regardless of the increase in the tightening torque. Further, in addition to monotonously increasing or decreasing the speed V _Ln in the low-speed tightening operation, it is possible to increase or decrease irregularly.

Further, in the tightening process of FIGS. 1, 4 and 5, the time t _Ln in the low-speed tightening operation is monotonously increased for each tightening operation, but in addition to this, the time t _Ln in the low-speed tightening operation is increased. Each tightening operation can be monotonously decreased, or irregularly increased or decreased.

Further, in the tightening process of FIGS. 1, 4 and 5, the speed V _Hn in the high-speed tightening operation is always constant throughout the tightening operation. In addition to this, as shown in FIG. The speed V _Hn can be monotonously increased for each tightening operation, or although not shown, the speed V _Hn can be monotonously decreased for each tightening operation, or irregularly increased or decreased.

As described above, the speed V _Hn or the time t _{Hn in} the high-speed tightening operation and the speed V _Ln or the time t _Ln in the low-speed tightening operation are set by the material of the object to be tightened the bolt 18 or the washer. It can be changed according to the presence or absence and the number of objects.

In embodiment of this invention, it is a characteristic view which shows an example of the relationship between the time in a clamping process, torque, and speed. It is a block block diagram which shows the handheld electric nutrunner in embodiment of this invention. It is a flowchart which shows the algorithm of the fastening operation | movement of FIG.1, FIG.4, FIG.5 and FIG. In other embodiment of this invention, it is a characteristic view which shows the other example of the relationship between the time in a clamping process, torque, and speed. In other embodiment of this invention, it is a characteristic view which shows the other example of the relationship between the time in a clamping process, torque, and speed. In other embodiment of this invention, it is a characteristic view which shows the other example of the relationship between the time in a clamping process, torque, and speed. It is a characteristic view which shows the relationship between the time in the fastening process in a prior art example, torque, and speed. It is a flowchart which shows the algorithm of a fastening operation | movement in a prior art example.

Explanation of symbols

18 Tightening object (bolt)
21 Controller T _C Target torque T _S Seating torque V _Hn Speed at high speed tightening operation V _Ln Speed at low speed tightening operation t _Hn Time at high speed tightening operation t _Ln Time at low speed tightening operation

Claims (10)

A nutrunner control method for tightening the object to be tightened from a seating torque when the object to be tightened is seated to a target torque when the object to be tightened is completed. , nut runner control method, characterized by controlling the rate and time at each clamping operation to increase the tightening torque in the tightening operation by repeatedly fast clamping operation and slow tightening operation.   The method of controlling a nut runner according to claim 1, wherein the speed in the high-speed tightening operation is constant or variable as the tightening torque increases for each tightening operation.   The method of controlling a nut runner according to claim 1 or 2, wherein the time for the high-speed tightening operation is constant or variable as the tightening torque increases for each tightening operation.   The method of controlling a nut runner according to any one of claims 1 to 3, wherein a speed in the low-speed tightening operation is constant or variable with an increase in tightening torque for each tightening operation.   The method for controlling a nut runner according to any one of claims 1 to 4, wherein the time in the low-speed tightening operation is constant or variable with an increase in tightening torque for each tightening operation. A nut runner for tightening the object to be tightened from a seating torque when the object to be tightened is seated to a target torque when the object to be tightened is completely tightened. nut runner characterized by comprising a controller for controlling the speed and time in each clamping operation to increase the tightening torque in the tightening operation by repeatedly tightening operation and slow tightening operation.   The nutrunner according to claim 6, wherein the controller controls the speed in a high-speed tightening operation to be constant or variable with an increase in tightening torque for each tightening operation.   The nutrunner according to claim 6 or 7, wherein the controller controls the time in the high-speed tightening operation to be constant or variable as the tightening torque increases for each tightening operation.   The nutrunner according to any one of claims 6 to 8, wherein the controller performs control so that a speed in a low-speed tightening operation is constant or variable with an increase in tightening torque for each tightening operation.   The nutrunner according to any one of claims 6 to 9, wherein the controller controls the time in the low-speed tightening operation to be constant or variable as the tightening torque increases for each tightening operation.

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