JP2023056090A - index device - Google Patents

Abstract

To provide an index device capable of performing automatic origin setting processing of a servo motor.SOLUTION: An index device includes: an indexing rotary body rotatably assembled so as to be covered with the housing; a servo motor having an absolute encoder; a speed reduction mechanism assembled into the housing to transmit the rotation of the servo motor to the indexing rotary body; a rotation switching mechanism including a curvic coupling comprising first and second curvic coupling pieces, switching between the rotation and the rotation limit of the indexing rotary body, and assembled into a housing; and a control device which includes an automatic origin setting processing section for coinciding the teeth of the first curvic coupling piece with the center of the groove of the second curvic coupling piece by drive control of the servo motor from a clamp state of the curvic coupling, and setting a rotation position output from the absolute encoder as an origin.SELECTED DRAWING: Figure 4

Description

The present invention relates to an index device having a curvic mechanism and capable of automatically setting the origin of a servomotor.

An index device for accurately indexing an angle is, for example, a turret device of a machine tool that selects and positions a predetermined tool from a plurality of tools. The turret device disclosed in Japanese Unexamined Patent Application Publication No. 2002-200001 uses a curvic coupling, and in a clamped state, the teeth of the turret tool post and the turret body are strongly pressed against each other. In the turret device, the appropriate tool is selected by turning indexing, and the target tool is positioned by engaging a curvic coupling. During processing, a predetermined processing is performed by, for example, applying a cutting tool to the rotating work. At that time, the tool receives resistance by cutting the workpiece, but the tool is supported by the meshed Garbic coupling.

JP-A-2006-15448

In the turret device, turning index control is performed by measuring the rotation angle from the origin set for the absolute encoder of the turning indexing servomotor. The origin setting of the rotation indexing servo motor in such a turret device is performed by the operator rotating the turret so that the mounting surface is at a position perpendicular to the vertical direction, and the rotational position at which the curvic coupling is engaged. Set as the origin. However, there is backlash between the meshing teeth, which cannot be seen directly, especially since it is built into the turret device, and cannot be rotationally positioned so that the centers of the teeth and grooves are properly overlapped. Therefore, when setting the origin of the turning indexing servomotor, the origin position varies greatly depending on the operator, and the time required to complete the setting also varies greatly.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an index device capable of automatically setting the origin of a servo motor.

An indexing device according to the present invention comprises an indexing rotor mounted rotatably so as to be covered by a housing, a servomotor having an absolute encoder, and the rotation of the servomotor being transmitted to the indexing rotor. a speed reduction mechanism incorporated in the housing; and a curvic coupling comprising first and second curvic coupling pieces in which a plurality of teeth are arranged in an annular shape. A rotation switching mechanism incorporated in the housing for switching between rotation and rotation limitation of the rotating body, and drive control of the first curvic coupling piece from the clamped state of the curvic coupling by the servo motor. and a control device having an automatic origin setting processor that aligns the tooth with the center of the groove of the second curvic coupling piece and sets the rotational position output from the absolute encoder as the origin.

According to the above configuration, the automatic origin setting processing section of the control device controls the drive of the servo motor from the clamped state of the curvic coupling, and the teeth of the first curvic coupling piece and the teeth of the second curvic coupling piece are driven. Since the center of the groove is aligned and the rotation position output from the absolute encoder is set as the origin, variations in the origin position due to differences in operators are eliminated, and the time to complete setting can be shortened.

1 is a cross-sectional view showing one embodiment of an indexing device; FIG. FIG. 4 is a front view of the turret head; FIG. 4 is a block diagram showing a control system for the turret device; FIG. 10 is an image diagram of automatic origin setting processing that is automatically performed; FIG. 7 is a diagram showing a flowchart of automatic origin setting processing;

An embodiment of an index device according to the present invention will be described below with reference to the drawings. In this embodiment, a turret device constituting a machine tool will be described as an example of the index device. FIG. 1 is a sectional view showing the turret device. The turret device 1 is configured such that the rotational output of a rotation indexing servomotor 2 is transmitted to a turret head 3 to perform rotation indexing for the turret head 3 on which a plurality of tools are mounted. In the turret head 3, the internal mechanism of the turret device 1 is covered by axially assembled housing members 11-16.

The turret device 1 has a drive shaft 5 that is rotated by a rotation indexing servomotor 2. A cylindrical extension member 7 is coaxially fixed to the drive shaft 5 and rotates within housing members 11-16. Rotation around the axis O is possible. Furthermore, the turret head 3 is coaxially fixed to the extension member 7 . In the turret device 1, a parallel shaft gear reduction mechanism is incorporated in the housing members 11-16 in order to transmit the rotation of the turning indexing servomotor 2 to the rotatable drive shaft 5. As shown in FIG.

In the gear reduction mechanism, a small-diameter motor gear 22 is first fixed to the motor shaft 21 of the rotation indexing servomotor 2 and meshes with a large-diameter first gear 23 . A small-diameter second gear (not shown) is coaxially formed integrally with the first gear 23 , and the second gear meshes with a large-diameter third gear 24 . Further, a small-diameter fourth gear 25 is formed coaxially with the third gear 24 , and the fourth gear 25 meshes with a fifth gear 26 fixed to the drive shaft 5 .

Therefore, in the turret device 1, when rotation is output by drive control of the orbiting indexing servomotor 2, reduced rotation is imparted to the drive shaft 5 via a series of meshing gears. A turret head 3 fixed to a drive shaft 5 via an extension member 7 is rotated by a predetermined angle, and a plurality of tools attached to the turret head 3 are rotated and indexed to be used for machining a workpiece. is done. In the turret device 1, the turret head 3 is positioned by the curvic coupling because the tool thus selected receives resistance during machining. As shown in FIG. 2, the turret head 3 of this embodiment has a decagonal shape, and a tool (not shown) can be attached to and detached from each side via a tool holder.

The curvic coupling consists of a rotating curvic coupling piece 31 that rotates integrally with the drive shaft 5 and the like, and a fixed curvic coupling piece 31 that is formed around the drive shaft 5 and assembled to a curvic coupling cylinder. It is composed of a coupling piece 32 . The rotation-side curvic coupling piece 31 is incorporated so as to be sandwiched between the drive shaft 5 and the extension member 7, and has annular teeth facing the drive shaft 5 side. The fixed-side curvic coupling piece 32 is integrally fixed to the piston 33 so as to be superimposed on the piston 33 in the axial direction. .

The curvic hydraulic cylinder is formed with a clamping side pressure chamber 35 and an unclamping side pressure chamber 36 so as to sandwich a piston 33 therebetween. is displaceable. In addition, a plurality of pins 37 parallel to the rotation axis O are projected from the piston 33 in the clamp-side pressurizing chamber 35 . On the other hand, a non-rotating cylinder block 39 fixed to the housing member 14 side is formed with a positioning hole into which a pin 37 is inserted to restrict the rotation of the piston 33 and the fixed curvic coupling piece 32. there is A coil spring 38 is provided around each pin 37 to urge the piston 33 toward the rotating curvic coupling piece 31 side.

In the turret device 1, a plurality of tools attached to the turret head 3 are selected by arm rotation indexing and positioned at positions where they can be processed. The drive control of the turning indexing servomotor 2 is performed by transmitting a rotational position command signal from the control device of the machine tool and converting it into a servo pulse by a servo amplifier. The servo pulse is generated based on a feedback signal from the encoder of the turning indexing servomotor 2 . As a result, the turret head 3 is stopped at a predetermined rotational position, and the turning index of the tool used for machining is performed.

Rotational output of the turning indexing servomotor 2 is transmitted by reducing the rotation of the motor gear 22 from the first gear 23 to the second gear and further to the third gear 24 , fourth gear 25 and fifth gear 26 . Accordingly, the drive shaft 5 and the turret head 3 are rotated by a predetermined angle under rotation control of the rotation indexing servomotor 2, and the corresponding tool is indexed in rotation. At this time, hydraulic oil is supplied to the unclamping side pressurizing chamber 36 of the Curvic cylinder, and the piston 33 is displaced toward the orbiting indexing servomotor 2 side, and the rotation side Curvic coupling piece 31 and the fixed side The engagement with the curvic coupling piece 32 is released.

After the turning indexing of the tool is completed, the working oil is supplied to the clamping side pressure chamber 35, while the working oil in the unclamping side pressure chamber 36 is discharged, and the piston 33 moves to the turret head 3. Displace to the side. As a result, the fixed-side curvic coupling piece 32 meshes with the rotary-side curvic coupling piece 31, and the rotation of the turret head 3 is restricted. The corresponding tool is fixed in the machining position and the workpiece can be machined.

In the turret device 1, the turning indexing servomotor 2 is driven and controlled by measuring the rotation angle from the set origin with an encoder in order to turn and index the corresponding tool to an accurate position. An absolute encoder 55 (see FIG. 3) is used in the turning indexing servomotor 2 of the turret device 1, which is NC-controlled. is also output. Therefore, in the turret device 1, the origin is set so that the turret device 1 can operate with rotational position data based on the origin.

In setting the origin, the operator turns the turret head 3 in an unclamped state in which the rotating curvic coupling piece 31 and the fixed curvic coupling piece 32 are separated. For example, as shown in FIG. 2, the first tool mounting portion 301 is positioned at the top, and positioning is performed such that its mounting surface is orthogonal to the vertical reference line L. As shown in FIG. Then, the rotary side curvic coupling piece 31 and the fixed side curvic coupling piece 32 are engaged with each other, fine adjustment for backlash is performed, and the rotational position is set as the origin. Traditionally, this fine adjustment has been performed manually by the operator. However, since the work was performed on a part of the housing that could not be seen directly, there was variation in the accuracy of each person in charge, and the work time until setting also varied greatly depending on experience.

In this respect, the present embodiment is configured so that the final origin setting is automatically performed. FIG. 3 is a block diagram showing the control system of the turret device 1. As shown in FIG. The control device 50 of the machine tool has an automatic origin setting processing unit 51 storing an origin setting program and a storage unit 52 storing information generated according to the processing, and drives the rotation indexing servomotor 2. Alternatively, it is configured to control the drive of the hydraulic circuit 56 of the curvic hydraulic cylinder.

FIG. 4 is an image diagram of the automatic origin setting process that is automatically performed, and shows the meshing teeth of the curvic coupling piece 31 on the rotating side and the curvic coupling piece 32 on the fixed side. FIG. 5 is a diagram showing a flowchart of automatic origin setting processing. In the automatic origin setting process executed by the origin setting program stored in the automatic origin setting processing unit 51, the turret head 3 is positioned at the rotational position shown in FIG. It is executed according to the origin setting signal transmitted from the display device 57 .

The angular position of the turret head 3 where the first tool mounting portion 301 is perpendicular to the vertical reference line L is set as the origin. In this case, as shown in FIG. 4(A), the teeth 41 of the curvic coupling piece 31 on the rotating side and the center lines M1 and M2 of the grooves 42 of the curvic coupling piece 32 on the stationary side are misaligned. Since it is difficult to manually correct this deviation as described above, automatic adjustment and origin setting are performed in this embodiment. In the automatic origin setting process, first, by driving the rotation indexing servomotor 2, a very slow speed (confirmation speed) is applied clockwise (to the right in the drawing) with respect to the rotating curvic coupling piece 31. Rotation is given (S101).

At this time, the tooth 41 of the rotating curvic coupling piece 31 moves clockwise in the groove 42 of the stationary curvic coupling piece 32 by the amount of the backlash, as shown in FIG. 4(B). Then, the teeth 41 of the curvic coupling piece 31 on the rotating side are brought into contact with the teeth 43 of the curvic coupling piece 32 on the stationary side at a very slow speed. As a result, the current supplied to the turning indexing servomotor 2, which receives a load due to contact with the teeth 41 and 43, gradually increases. This current is confirmed in the automatic origin setting process, and it is determined whether or not the supplied current exceeds X% of the rating (where X is an arbitrary value) (S102).

If the supplied current does not reach X% of the rated value (S102: NO), clockwise rotation of the rotating curvic coupling piece 31 and determination of the current value are continued (S101, S102). After that, when the supplied current reaches X% of the rated value (S102: YES), the rotational position W1 is recorded in the storage section 52 of the control device 50 (S103). By the way, in such a measurement, the rotating curvic coupling piece 31 is rotated by a micron unit clearance due to backlash, and the rotational position W1 is obtained based on the change in the current value that occurs at that time. Therefore, the confirmation speed is a very slow speed that allows determination of the rotational position at such extremely small distances. For example, in this embodiment, the speed is about 1% of normal operation.

Subsequently, the driving of the turning indexing servomotor 2 is switched, and the rotating curvic coupling piece 31 is rotated counterclockwise (to the left in the drawing) at a very slow speed for confirmation ( S104). Therefore, as shown in FIG. 4(C), the teeth 41 of the curvic coupling piece 31 on the rotating side move in the grooves 42 of the curvic coupling piece 32 on the fixed side and come into contact with the teeth 44 on the opposite side.

Here too, the current supplied to the turning indexing servomotor 2 gradually increases due to the load caused by the tooth 41 of the rotating curvic coupling piece 31 coming into contact with the tooth 44 of the stationary curvic coupling piece 32 . Therefore, the current value is confirmed, and it is determined whether or not the supplied current exceeds X% of the rating (S105). If the supplied current does not reach X% of the rated value (S105: NO), clockwise rotation of the curvic coupling piece 31 on the rotating side and determination of the current value are continued (S104, S105). After that, when the supplied current reaches X% of the rated value (S105: YES), the rotational position W2 is recorded in the storage section 52 of the control device 50 (S106).

Next, a central position W between the rotational position W1 and the rotational position W2 read from the storage unit 52 is calculated (S107). The central position W is the center of the groove 42 of the fixed curvic coupling piece 32 . Therefore, by drive control of the rotation indexing servomotor 2, the rotation side curvic coupling piece 31 is rotated clockwise from the rotation position W2, and alignment at the center position W is performed (S108). . That is, as shown in FIG. 4D, the center line M1 of the tooth 41 overlaps the center line M2 of the groove 42. As shown in FIG. Then, the rotational position output from the absolute encoder 55 with the center lines M1 and M2 shown in FIG. 4(D) overlapping is set as the origin and stored in the storage unit 52 of the control device 50 (S109).

Therefore, according to this embodiment, since the origin setting is automatically performed, variations in the origin position caused by different operators are eliminated, and the time required to complete the setting can be shortened. In addition, such an effect can be obtained by control without adding structural improvements to the conventional turret apparatus.

Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.
For example, in the above embodiment, the turret device 1 was described as an example, but it is also applicable to other index devices.

REFERENCE SIGNS LIST 1 turret device 2 rotation indexing servomotor 3 turret head 5 drive shaft 11-16 housing member 22-26 gear 31 rotating side curvic coupling piece 32 fixed side curvic coupling piece 33 ... Piston 35 ... Clamp side pressure chamber 36 ... Unclamp side pressure chamber 50 ... Control device 52 ... Storage unit 55 ... Absolute encoder

Claims (4)

an indexing rotor rotatably assembled so as to be covered by the housing;
a servomotor with an absolute encoder;
a reduction mechanism incorporated in the housing for transmitting the rotation of the servomotor to the indexing rotor;
The housing is provided with a curvic coupling consisting of first and second curvic coupling pieces in which a plurality of teeth are arranged in an annular shape, and the clamping and unclamping of the curvic coupling switch between rotation and rotation limitation of the indexing rotor. a rotation switching mechanism incorporated within;
From the clamped state of the curvic coupling, the tooth of the first curvic coupling piece and the center of the groove of the second curvic coupling piece are aligned by drive control of the servomotor, and output from the absolute encoder. a control device comprising an automatic origin setting processing unit that sets the rotational position to be the origin as the origin;
indexing device with The automatic origin setting processing unit moves the teeth of the first curvic coupling piece integrally formed with the indexing rotor to the non-rotating second curvic coupling provided on the rotation switching mechanism side. By moving clockwise and counterclockwise within the groove of the strip and striking each tooth on either side of the groove, the motor is driven in both directions when the current supplied to the servomotor reaches a preset value. 2. A rotational position is stored, a tooth of said first curvic coupling piece is positioned at a central position calculated from said rotational positions in both directions, and the rotational position output from said absolute encoder at that time is set as an origin. The indexing device as described in . 3. A mechanism according to claim 2, wherein said rotation switching mechanism has a hydraulic cylinder for displacing a non-rotating piston in the axial direction of said indexing rotor, and said second curvic coupling piece is fixed to said piston. Indexing device as described. The automatic origin setting processing unit moves the teeth of the first curvic coupling piece in the groove of the second curvic coupling piece at a very slow confirmation speed different from that during normal operation. An indexing device according to claim 2 or claim 3.

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