JPH0487756A - Control device for workpiece index head - Google Patents

Abstract

PURPOSE:To prevent a workpiece supporting bed from being turned to an undesired range of turning by additionally providing a simple detecting means so that a reset direction to the original point of a workpiece index head can be surely recognized in a turning region of the workpiece supporting bed. CONSTITUTION:When an original point reset command is output, first whether the first detector 41 is turned on or not is judged. In the case that the detector 41 is turned on further with an output of the second detector 42 off, original point reset action of forward rotation is advanced. First, an index head is forward rotation-reset at a high speed, and when it is judged to be placed in a deceleration region by a microcomputer 17, the head is deceleratedly rotated by a stepping motor M. The head, when it is returned to the original point, is stopped. In the case of the detector 42 turned on, the head is reverse rotation reset. The head, when it is reversed till passing the deceleration region, is transferred to deceleration forward rotation action.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a workpiece indexing table that rotates a workpiece support table and makes a workpiece part of a workpiece supported by the workpiece support table face a tool. In particular, the present invention relates to a control device for a workpiece indexing table that allows the workpiece supporter to rotate forward or backward within its rotational range when returning the workpiece supporter to its original position.

[Conventional technology]

There is a workpiece indexing table that performs indexing operation by motor control, which allows the workpiece to be machined to face the tool.

In this method, a workpiece support base supporting a workpiece is rotated about an axis, and this rotational operation is performed by a stepping motor or a servo motor. In this workpiece indexing table, the rotation angle of the motor is controlled by a predetermined program, and by setting the rotation angle of the workpiece support table, the part to be machined on the workpiece is indexed to a position facing the tool.

[Problem to be solved by the invention]

In this type of workpiece indexing table, a certain angular position of the workpiece support is the machine origin, and the indexing angle is set with this origin as the starting point. Therefore, when machining of the workpiece is completed or at the stage of starting machining anew, it is necessary to return the workpiece support base to this machine origin by motor control. Generally, this return-to-origin operation is executed by parameters set in the command setting of the microcomputer, and these parameters control the workpiece support base to return to the origin in one return direction, either forward rotation or reverse rotation.6 However, the workpiece indexing table and Depending on the proximity to other devices, the size of the workpiece, etc., there may be an angular range in which it is not desired to rotate the workpiece support. Alternatively, when a hydraulic or air hose or an electrical signal cord is connected to the workpiece support, if the workpiece support is rotated more than 360 degrees, the hoses may be twisted. However, in conventional control methods, when the return-to-origin direction is determined by parameters, the workpiece support table rotates in an angle range that is not desired, causing interference with other devices that are close to the workpiece support table or workpiece. Otherwise, the work support table may rotate more than 360 degrees, causing the hose or cord to become twisted.

The present invention solves the above-mentioned conventional problems, and by adding a simple detection means, it is possible to reliably recognize the direction in which the workpiece indexing table returns to its origin within the rotation area of the workpiece support table. It is an object of the present invention to provide a control device for a workpiece indexing table that can prevent a workpiece support table from rotating in an undesired range.

- [Means for Solving the Problems] The present invention includes a workpiece support that rotates around a support shaft, a motor that rotates the workpiece support, and a drive control of this motor to move the workpiece support to a predetermined position. In a control device for a workpiece indexing table, the control device is provided with a control means for angularly rotating a workpiece supported on a workpiece support table to face a tool.

A detection member having a detection range of a predetermined angle is provided on the detection table that rotates together with the workpiece support base via the support shaft, and a detector is provided on the fixed side opposite to the detection member. The present invention is characterized in that, depending on whether or not the detection range of the detected member is detected by the detector, an output is obtained to determine whether the return direction is normal rotation return or reverse rotation return when the work support base returns to the origin. .

Further, in the above means, the detected member having a detection range of a predetermined angle that determines the permissible rotation angle of the workpiece support is placed on the same table as the detection table on which the detected member for obtaining the determination output of the return direction is provided. A detector is provided on the fixed side facing the detected member, and depending on whether or not the detection range of the detected member is detected by this detector, it is determined that the angle is outside the permissible rotation angle of the workpiece support base. When detected, a stop output of the motor is obtained.

Furthermore, the detected member is attached to the detection table so as to be variable in position in the circumferential direction around the axis.

[Effect]

In the above means, in a device that rotates a workpiece support table by a predetermined angle under drive control of a motor and indexes a workpiece part of a workpiece supported by the workpiece to a position facing a tool, the detected object rotates together with the workpiece support table. Depending on whether or not the detector detects the detection range of the member, it is possible to judge whether to rotate it forward or reverse in order to return to the origin.

Furthermore, a detected member that determines the permissible rotation angle is installed on the same table as the detected member, and detects when the workpiece support table is about to rotate beyond the permissible rotation angle, and controls the motor of the indexing table. It is supposed to stop. Therefore, in the event of a setting error in the return-to-origin direction, a programming error, or an unexpected runaway, it is possible to prevent the workpiece support base from rotating outside the limited rotation range.

Further, by attaching each detected member to the detection table in a variable position state, the normal rotation return or reverse rotation return range and rotation permissible range of the workpiece support base can be freely set in accordance with various conditions.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing the workpiece indexing table, and FIG. 2 is a cross-sectional view taken along the line -■ in FIG.

In FIG. 1, reference numeral 1 indicates a pedestal. Support side plates 3 and 4 are attached at right angles to both sides of the workpiece support base 2, and each of the support side plates 3 and 4 is provided with a coaxial support shaft 5.6. The support shaft 5 provided on one support side plate 3 is connected to a bearing (not shown) provided in the rotation drive unit 10.
A support shaft 6 provided on the other support side plate 4 is rotatably supported by bearings 8 a and 8 b in a support base 7 installed on the pedestal 1 .

A ohm wheel 11 is fixed to the outer periphery of the support shaft 5 supported within the rotary drive section 10. Further, a worm 12 that meshes with the ohm wheel 11 is provided within the rotary drive section 10. Also warm 12
is provided with a coaxial gear 13. Also this gear 1
A transmission gear 14 meshing with the transmission gear 1 is provided.
4 meshes with the pinion 15 of the stepping motor M. The power of the stepping motor M is transmitted from the pinion 15 to the transmission gear 14 and further to the gear 13, and then to the worm 1.
2 and is transmitted to the worm wheel 11 at a reduced speed, thereby driving the support shaft 5 and the workpiece support base 2 to rotate in forward and reverse directions. This stepping motor M is controlled by a microcomputer, and the workpiece support table 2 is indexed to a predetermined rotation angle position by its control operation. Although there are various configurations of means for controlling the stepping motor M, FIG. 3 illustrates the most basic one. Microcomputer 17
A drive pulse P1 having a pulse number and frequency corresponding to the rotation angle and rotation speed is outputted from the drive pulse. Stepping motor M
An absolute encoder 16 is provided.

In the subtracter 18, the drive pulse P1 is subtracted by the feedback pulse P from the absolute encoder 16, and the stepping motor M rotates by the commanded angle.

A rotary joint 21 is connected to the right side of the rotary drive unit 10 in the drawing. A shaft 22 provided coaxially with the support shaft 5 extends into this rotary joint 21, and an air supply pipe 23 connected to this rotary joint 21 is connected to a passage 2 in the shaft 22.
Air is sent into 2a. This air is supplied to clamp cylinders 25a and 25b on the workpiece support 2 through an air pipe 24 shown by a dashed line. Clamp cylinder 2
5a and 25b are spring return type; for example, when air is supplied, the clampers 27a and 27b are lowered to clamp the work W, and when the air supply is stopped, the clampers 27a and 27b are lowered.
7a and 27b are returned by the spring and the clamp is released. At this time, the negative pressure in the spring chamber is
7 through the air pipe 26. Alternatively, hydraulic pressure may be supplied by the rotary joint 21, and clamping and unclamping may be performed by hydraulic drive. Reference numeral 28 is a clamp limit switch. Further, in FIG. 1, a tool T for machining a workpiece W is illustrated by a chain line.

A disc-shaped detection table 30 is attached to the left end of the support shaft 6 on the left side in FIG. As shown in Fig. 2, the detection table 3
0 extends in the circumferential direction around the support shaft 6.
Two support grooves 30a and 30b are formed over the entire circumference. As shown in FIG. 1, these support grooves 30a and 30b
has a T-shaped cross section. A first groove is formed on the surface of the support groove 30a.
A detection dog (detected member) 32 is installed. This detection dog 32 has a partially arcuate shape. A bolt extending from a T-shaped block 34 slidably inserted into the support groove 30a having a T-shaped cross section protrudes outward from a hole provided in the flange portion 32a of the detection dog 32, and a nut 35 is tightened onto the bolt. As a result, the detection dog 32 is fixed to the detection table 30. Similarly, the support groove 30 on the outer peripheral side
A second detection dog (detected member) 33 having a partially circular arc shape is installed on the surface of b. A T-shaped block 34 is slidably inserted into the support groove 30b, and a bolt extending from the T-block 34 projects outward from a hole in the flange portion 33a of the detection dog 33. A nut 35 is tightened to this, and the detection dog 33
is fixed to the detection table 30. Each detection dog 32
and 33 can be freely changed in their mounting positions, by loosening the nuts 35 tightening each and sliding the T-shaped block 34 within each support groove 30a or 30b.
Each detection dog 32 and 33 can be freely moved and stopped along the circumference of the support grooves 30a and 30b. It is also possible to prepare detection dogs 32 and 33 with different arc lengths and to freely replace them, or to increase or decrease the number of dog plates.

As shown in FIG. 1, the pedestal 1 is provided with a detector support plate 40, on which a first detector (proximity switch) 4 is mounted.
1 and a second detector (proximity switch) 42 are provided. The first detector 41 detects the first detection dog 32, and is turned on when the detector 41 faces the detection dog 32. Second detector 4
Reference numeral 2 detects the second detection dog 33, and the switch is turned on when facing the detection dog 33.

As shown in FIG. 3, the outputs of the detectors 41 and 42 are sent from the detection circuit 43 to the microcomputer 17.

Next, the detection angle by the detection dogs 32 and 33 in the above embodiment will be explained. Figure 4 (Al is work support stand 2
Also, the detection table 30 is shown at the machine origin. At this time, for example, the first detection dog 32 is
At the origin position in A), it extends from the detection position by the detector 41 by an angle θ1 in the CW force direction (clockwise) and an angle θ8 in the CCW direction (counterclockwise). This first detection dog 32 is for limiting the permissible rotation angle of the workpiece support base 2, and even if the workpiece support base 2 exceeds the angle within the detection range (θ, +02) of the detection dog 32, it will not rotate. In order to prevent the operation from continuing, here, when the detection dog 32 is not detected, that is, the output of the first detector 41 is set to O.
When the FF becomes FF, a motor stop command is issued from the microcomputer 17, and the motor M is stopped. Further, as shown in FIG. 4(A), for example, the second detection dog 33 extends in the CCW direction from the detection position by the second detector 42 at the machine origin. That is, the second detection dog 33 and the first detection dog 32 overlap in the detection range of θ in the CCW direction. Furthermore, the second detection dog 3
3 is shown in FIG. 4 (also in the CCW direction in Al, there is a detection range of an angle α; this angle α will be described later).

The second detection dog 33 is for determining whether to return to the normal rotation or to return to the reverse rotation when returning to the origin.
As shown in Fig. 4 (Bl), when returning to the origin from the indexed position rotated in the CCW direction from the origin position (position in Fig. 4 (A)), the output from the second detector 42 is
Since it is a FF, at this time a command is issued from the microcomputer 17 to the stepping motor M, and the workpiece support base 2 is CW.
Rotates forward in the force direction and returns to the origin. For example, Fig. 4 (C)
As shown in FIG.
Since the output of stepper motor 2 is ON, the workpiece support base 2 is reversely rotated in the CCW direction by a command to the stepping motor M to return to the origin.

In the illustrated embodiment, the range indicated by β in FIG. 4 is the deceleration region. The angle β of this deceleration region is set to, for example, about 18 degrees according to the control program. When rotating in the CW force direction from the position Bl in FIG. 4 to return to the origin, it returns at high speed to just before β, is decelerated within the angular range β, and stops at the origin position in FIG. 4A. Also the fourth
When returning to the origin by rotating in the CCW direction from the state shown in figure (C), rotate in the CCW direction until passing the origin position by -1, then rotate in the opposite direction after passing the angle β to decelerate in the CW force direction. It rotates, returns to the origin position shown in FIG. 4 TAI, and stops.

The extension portion of the second detection dog 33 in the CCW direction corresponding to the angle α shown in FIG. 4 fAl is provided in relation to the above-mentioned deceleration operation. In other words, as shown in Figure 4 (D), a small angle (an angle smaller than β) from the origin position to the CCW direction.
When returning to the origin from a position where the motor has moved and stopped, the normal rotation return region (CW direction return region) should be the normal rotation return region, but it has already entered the deceleration region. Here, since the second detection dog 33 has an extension portion corresponding to α, the output from the second detection section 42 is ON. Therefore, the microcomputer 17 determines that it is in the reverse rotation return region, and the motor is driven in the CCW direction. As a result, it is possible to rotate in the CCW direction beyond the deceleration region, and after passing the deceleration region, it is decelerated in the CW force direction and driven, and can return to the original position shown in FIG. 4+A). In other words, when returning to the origin from a state where it is slightly rotated in the CCW direction from the origin position as shown in FIG. 4(D), the extension of α of the second detection dog 33 causes The detection output is similar, so the fourth
A control similar to that shown in Fig. fc) is performed to enable return to the origin after passing through the deceleration region at an angle of β.

Next, the operation will be explained.

As shown in FIG. 1, the workpiece W is placed on the workpiece support stand 2 and clamped by the clamp cylinder 25a.

The clampers 27a and 27b are lowered by the clamper 25b and the workpiece W is clamped. Based on the indexing angle information that has been input in advance, the microcomputer 17 sends the drive pulses P,
is output, and the stepping motor M rotates forward or reverse by a predetermined number of rotations. This power is gear 15.1
After passing through 4.13 degrees, the deceleration is transmitted from the ohm 12 to the ohm wheel 11, the support shaft 5 is driven, the workpiece support base 2 is rotated, and the part to be machined on the workpiece W is in a position opposite to the tool T. It is determined. Then, a predetermined process is performed on the workpiece W using the tool T. The above-mentioned indexing angle is programmed within the angle range of the first detection dog 32 shown in FIG. 3
2 and the angle detected by the first detector 41 as shown in FIG.
Control is performed so that indexing beyond the detection range of the angle (θ1+θ,) of the first detection dog 32 shown by Al is not performed.

It is necessary to return the -H workpiece support base 2 to its origin in order to replace the workpiece after machining is completed or at the stage of starting machining anew. The control of the return-to-origin operation at this time will be explained based on the flowchart of FIG.

When the home return command is issued in step (a), it is first determined whether the first detector 41 is ON or not (step (b)). If it is OFF, the workpiece support 2
Since is in the indexing prohibited area, the return-to-origin operation is canceled and
It can be switched to means such as display or manual control. If the detector 41 is ON, the process advances to step (cl). If the output of the second detector 42 is OFF in this step, normal rotation (CW force direction return-to-origin operation begins).

First, in order to return to normal rotation at high speed (step (d)), when the microcomputer 17 determines that it has entered the deceleration region (
In step (el), the stepping motor M decelerates and rotates forward (step (f)), and stops when it returns to the origin (step (gl(h)). In the step (cl), the detector 42 was ON. in case of,
When the rotation is reversed and returned (step (i)), and the rotation is reversed until it passes through the deceleration region in step (j), the process shifts to the deceleration and normal rotation operation of step (fl).

If the above control operation corresponds to FIG. 4, when returning to the origin from a position indexed in the CCW direction from the origin as shown in FIG. 4(B), from step (C) to step (d
The flow is less than l. Also, as shown in Figure 4 (C), when returning to the origin from a position indexed in the CW force direction from the origin, the flow is from step (C1) to step (il). When returning to the origin from a position that is slightly indexed in the CCW direction from the origin, the detection output of the second detector 42 is ON due to the extension of the angle α of the second detection dog 33. The flow is as follows from step fcl to step (i).

In the above explanation, the determination of whether or not the deceleration region has entered in step (e) and whether or not the deceleration region has been passed in step (j) is made by inputting the angle β of the deceleration region in advance into the program, Based on the rotational position of the motor M, a microcomputer determines whether or not the angle is within this range. However, the extension of the angle α of the second sensing dog 33 can also be used for this determination. That is, when the second detector 42 detects the left end of the second detection dog 33 in the illustration when returning to normal rotation from the state shown in FIG. 4(B), it issues a deceleration and normal rotation command to the motor M based on this detection output. You may also issue Figure 4 (C1
When returning in reverse at (Dl), a normal rotation deceleration command is issued to the motor M when the second detector 42 is disconnected from the second detection dog 33 and turned OFF. This eliminates the need to program the deceleration region B in advance.

Note that the first detection dog 32 is set within the permissible rotation range and the first detection dog 32 is
The output of the motor stop is obtained when the detector 41 of Similarly, the second
Conversely, the detection dog 33 is also set to the normal rotation return range that corresponds to the detection range, and when the second detector 42 is ON, normal rotation return,
An output of reverse rotation return may be obtained when the switch is OFF.

In addition, in the illustrated embodiment, a detection table 30 is provided on the support shaft 6 on the left side in FIG. to 2
As shown by the dotted chain line, the support shaft 5 on the rotation drive unit 10 side
Alternatively, a detection table 30' may be provided on the extended axis to detect the angle of the support base 2.

Further, the motor for indexing operation is not limited to a stepping motor, but may be an AC or DC servo motor.

〔effect〕

As described above, according to the present invention, by detecting the detection range of the detected member that rotates together with the workpiece support in the first detection unit and the detector that detects the detected member, it is possible to detect the return to the origin in normal rotation. Since it is possible to determine whether the workpiece is returning to the origin after reversing, by setting the detection range according to the detected member, it is possible to prevent the workpiece support base from rotating in an unexpected direction when returning to the origin. This prevents inconveniences such as workpieces interfering with other equipment or hoses and cables being twisted. Furthermore, by providing a detected member that determines the permissible rotation angle of the workpiece support table, it is possible to prevent the workpiece support table from exceeding the permissible rotation angle due to a setting error in the return direction, a programming error, or an unexpected runaway. At this time, the motor can be stopped to prevent the workpiece support from rotating, significantly increasing safety.

By providing the above two types of detected members on the same table, the detection section can be formed compactly. Furthermore, by making it possible to adjust the mounting position of the detected member, it becomes possible to freely and easily change or set the normal rotation and reverse rotation ranges and the permissible rotation angle according to conditions.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view of a workpiece indexing table according to the present invention, and FIG.
3 is a circuit block diagram showing an example of a motor control section, FIGS. 4A to 4D are explanatory diagrams showing the origin return operation, and FIG. 5 is a flowchart of the origin return operation. DESCRIPTION OF SYMBOLS 1... Frame, 2... Work support stand, 5.6... Support shaft, 10... Rotation drive part, M... Stepping motor, 16... Absolute encoder, 17...
・Microcomputer, W...Work, 25a, 25b...Clamp cylinder, 27a, 27b...Clamper, 3o
... detection table, 32... first detection dog (detected member), 33... second detection dog (detected member),
41...first detector, 42...second detector. (B) (D) Figure 4 Figure 5

Claims (1)

[Claims] 1. A workpiece support that rotates around a support shaft, a motor that rotates the workpiece support, and a workpiece support that rotates the workpiece support at a predetermined angle by driving and controlling this motor. In a control device for a workpiece indexing table, the control device is provided with a control means for making a workpiece part of the workpiece supported on the table face the tool, and a detection table that rotates integrally with the workpiece support table via the support shaft; A detected member having a detection range corresponding to a predetermined angle is provided, a detector is provided on the fixed side facing the detected member, and the workpiece is determined by whether or not the detection range of the detected member is detected by this detector. A control device 2 for a workpiece indexing table, characterized in that it obtains an output for determining the return direction, whether normal rotation return or reverse rotation return, when the support table returns to the origin, and a detected member for obtaining the determination output for the return direction. A detected member having a detection range of a predetermined angle that determines the permissible rotation angle of the workpiece support is provided on the same table as the provided detection table, and a detector is provided on the fixed side opposite to the detected member, The workpiece indexing table according to claim 1, wherein the detector outputs a stop output of the motor when it is detected that the rotation angle of the workpiece support table is outside the permissible rotation angle based on whether or not the detection range of the detected member is detected. Claim 1 wherein the control device 3 and the detected member are attached to the detection table so as to be variable in position in the circumferential direction centering on the axis.
Or the control device for the workpiece indexing table described in 2.