JP2580071Y2 - Rolling machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling machine for producing splines and screws, and more particularly, to a rolling machine provided with a control device for controlling a pair of dies at equal speeds of two motors. It is about.

[0002]

2. Description of the Related Art Conventionally, rolling machines have been widely used for producing splines and screws. Rolling is a method of rolling while pressing a die against a workpiece, which is a workpiece, and copying the inverse shape of the die onto the workpiece to cause plastic deformation. Rolled splines, etc., are plastically deformed only in and around the thread and the streamline of the thread structure is continuous. Because the surface is smooth, it is superior in strength to cutting splines and the like. Therefore, a rolling machine is used for processing a precise spline shaft and the like.

[0003] Since the above-mentioned rolling process is plastic working and requires a large force of 1 ton or more, a conventional rolling machine uses a pair of hydraulic cylinders to move a pair of dies to a work.
Rolling was performed by moving from opposite directions. Here, a pair of dies are synchronized with each other by a pair of racks provided on each die and a pinion meshing with the pair of racks. In the rolling process, there is a large load change when the die is engaged with the work to start the rolling, but the hydraulic cylinder is excellent in that the work is always balanced because the thrust is constant. However, when a large force is applied in the rolling process, the binion and the rack undergo elastic deformation, so that the pair of dies cannot be accurately synchronized, and a precise spline shaft or the like cannot be manufactured. .

In recent years, spline shafts have been widely used in drive devices and the like, and as the demands on feed accuracy when using splines have become strict, it has been desired to supply precise spline shafts at low cost. As means for solving the above problem, for example, in Japanese Utility Model Publication No. 3-18023,
A rolling machine in which a pair of dies are mounted on a pair of sliders that mesh with a pair of ball screws, and a pair of ball screws are feedback-controlled at an equal speed by two speed control units and one position / speed control unit by two servo motors. Has been proposed.

[0005]

[Problems to be Solved by the Invention] However, the above rolling machine has the following problems. (1) Since plastic working with a rolling machine requires a large force, a large servomotor of about 7 KW is required for a servomotor to be used, but a large servomotor has a speed control required for feedback control. Including units, 1
The equipment cost increases because it costs more than 2 million yen per vehicle,
The price of splines and the like to be manufactured was high. (2) Also, when a large load change occurs suddenly, such as at the start of rolling, the ball screw may be stretched by elastic deformation, so that the processing accuracy of splines and the like is deteriorated. The present invention has been made to solve the above problems, and has as its object to provide an inexpensive rolling machine capable of manufacturing an accurate spline shaft and the like.

[0006]

SUMMARY OF THE INVENTION A rolling machine according to the present invention comprises a pair of ball screws rotatably supported by a frame, a pair of sliders which mesh with each of the ball screws and move in parallel by the rotation of the ball screws, and each of the sliders. A rolling machine having a pair of dies mounted on a rolling machine for rolling by moving a pair of dies in opposite directions by rotating a ball screw, and generally rotating one of the ball screws. It has a motor, a servomotor that drives the other of the ball screws to rotate, an encoder that detects the rotation angle of the general-purpose motor, and a constant-speed control device that controls the servomotor to rotate at the same speed as the general-purpose motor based on the output of the encoder. doing.

Further, the above-mentioned rolling machine has a small servomotor for rotating one of the ball screws driven by the general-purpose motor when the general-purpose motor and the servomotor are stopped. Further, the above-mentioned rolling machine has a pair of racks fixed to each of the pair of sliders, and a pinion with which the pair of racks mesh.

[0008]

The general purpose motor of the rolling machine according to the present invention having the above-described structure rotates a single ball screw to linearly move a die attached to a slider toward a workpiece as a workpiece. . The encoder sends the detected rotation angle of the general-purpose motor to the constant velocity control device. On the other hand, the constant speed control device drives the servo motor to rotate at a constant speed with the general-purpose motor. When the servo motor is driven at the same speed as the general-purpose motor, the other ball screw is rotated at the same speed as the ball screw driven and rotated by the general-purpose motor. Rolling is performed by approaching at a speed. Here, the speed of the general-purpose motor suddenly decreases at the start of rolling, but the rotation of the servomotor is also maintained at a constant speed, so that the processing accuracy of the rolling can be maintained, and a high-precision spline can be manufactured. can do.

Further, when exchanging the dice, it is necessary to attach the dice to the slider in a state where the positions of the dice and the work are accurately set. Therefore, it is necessary to accurately stop the position of the slider at a predetermined position on the rolling machine. However, it is difficult to move the slider by inching with a general-purpose motor. The small servo motor of the rolling machine according to the present invention can accurately stop the slider at a predetermined position by rotating the general-purpose motor and the ball screw attached to the general-purpose motor by inching when the servo motor is not driven. Therefore, the dies can be exchanged quickly and accurately.

Further, when the pair of dies engage with the workpiece and start rolling, the speed of the general-purpose motor is rapidly reduced, so that the ball screw rotated by the general-purpose motor is overloaded and the ball screw is elastically deformed. However, a pair of racks and pinions prevent overload on the ball screw.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rolling machine embodying the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the entire configuration of the rolling machine. FIG. 2 is a sectional view taken along line XX of FIG. The entire frame 5 of the rolling machine is manufactured by casting. In the center of the frame 5 is a work 14 which is a workpiece.
Are held between the pair of center pins 13 as shown in FIG. As shown in FIG. 1, a pair of ball screws 1 and 9 are rotatably supported by a bearing 10 at positions equidistant from the work 14, respectively. The ball screws 1 and 9 are provided with a slide 4 that holds a large number of balls in a retainer and moves along the ball screw by rotation of the ball screw. The connecting member 8 is fixed to the sliding body 4.

On the other hand, a pair of dovetail-shaped guide bars 6 are fixed to the frame 5. In addition, a pair of sliders 7 which are fitted in the dovetail grooves of each guide bar 6 and are slidable are provided. A die holder 11 is fixed to each slider 7. A die 12 is detachably attached to the die holder 11. Here, the pair of dies 12 are located symmetrically with respect to the center of the work 14. Since the slider 7 is screwed to the connecting member 8, the die 12, the die holder 11, the slider 7, the connecting member 8, and the sliding body 4 slide integrally with the ball screws 1, 9. .

The left end of the ball screw 1 extends to the outside of the frame 5, and the ball screw 1 is provided with a pulley for a timing belt 17. The timing belt 17 integrally rotates the ball screw 1 and the general-purpose motor 2 via a pulley attached to a shaft of the general-purpose motor 2 attached to a bracket 40 fixed to the frame 5. Here, the general-purpose motor uses a three-phase induction motor with an output of 5 KW. A pulley for the timing belt 18 is attached to the ball screw 1. The timing belt 18 is a small servomotor 20 having an output of 40 W attached to a bracket fixed to the frame 5.
Ball screw 1 through a pulley attached to the shaft of
And the small servomotor 20 are integrally rotated.

The small servomotor 20 is provided with an absolute type rotary encoder 21 for detecting the rotation angle and the rotation speed of the small servomotor 20. The left end of the ball screw 1 is connected to a shaft of a rotary encoder 19 attached to a bracket fixed to the frame 5. The rotary encoder 19 is an absolute type rotary encoder for detecting a rotation angle and a rotation speed of the general-purpose motor 2.

The right end of the ball screw 9 extends to the outside of the frame 5, and the ball screw 9 is provided with a pulley for a timing belt 15. The timing belt 15 integrally rotates the ball screw 9 and the servomotor 3 via a pulley attached to a shaft of the large servomotor 3 having an output of 7 KW attached to a bracket 40 fixed to the frame 5. Let it. The servo motor 3 is provided with an absolute type rotary encoder 16 for detecting the rotation angle and rotation speed of the servo motor 3.

Next, a control device for a rolling machine will be described. FIG. 4 is a block diagram showing the configuration of the control device. The main control device 29 of the rolling machine includes a general-purpose motor 2, a constant speed control device 22 for rotating and driving the large servo motor 3, a servo motor inching drive device 25 for inching drive of the small servo motor 20, and a rotary motor. Encoder 1
9, the rotary encoder 16 is connected. The constant speed control device is connected to the servomotor 3, a rotary encoder 16 for detecting the rotation speed of the servomotor 3, and a rotary encoder 19 for detecting the rotation speed of the general-purpose motor. The constant speed control device 22 compares the output values of the two rotary encoders 16 and 19, compares the rotational speeds of the general-purpose motor 2 and the servomotor 3, and outputs a difference between the two. And a servo motor speed control unit 23 for receiving the output of the difference and causing the rotation speed of the servo motor 3 to follow the rotation speed of the general-purpose motor 2 at a constant speed.

Next, the operation of the rolling machine having the above configuration will be described. The spline that has been subjected to the rolling process is replaced with a new work 14 by a work replacing device (not shown). At this time, the pair of dies 12 are at the origin position, which is a position farther from the work 14 than the position shown in FIG. Naturally, the distance between the pair of dies 12 and the work 14 is exactly matched. In the rolling machine according to the present embodiment, since the stop position of the general-purpose motor 2 cannot be accurately controlled, the absolute position at which the general-purpose motor 2 stops is detected by a rotary encoder 19 which is an absolute type rotary encoder, and the position is detected. The main control unit 29 controls the absolute position of the rotary encoder 16 of the servomotor 3 as the origin at that time.

Main controller 29 energizes general-purpose motor 2 to rotate ball screw 1 via timing belt 17. At this time, the rotation speed of the general-purpose motor 2 is detected by the rotary encoder 19 and the speed comparison unit 24
Is output to The main controller 29 drives the servo motor 3 via the constant-speed controller 22 at the same time as driving the general-purpose motor 2. At this time, the servo motor 3
Is detected by the rotary encoder 16 and output to the speed comparator 24.

The speed comparing section 24 compares the outputs of the rotary encoder 19 and the rotary encoder 16 and
The difference is sent to the servo motor speed controller 23. The servo motor speed controller 23 controls the speed of the servo motor 3 so as to eliminate the difference. Thereby, the general-purpose motor 2 and the servo motor 3 are rotated at a constant speed, and the ball screw 1 and the ball screw 9 are rotated at a constant speed. Then, the pair of dies 12 approach the work 14 at a constant speed from opposite directions, and simultaneously contact the work 14.

Next, when the die is engaged with the work 14 and the rolling process is started, a large load change is applied to the general-purpose motor 2, so that the rotation speed of the general-purpose motor 2 is rapidly reduced. Also at this time, since the constant speed control device 22 rapidly reduces the rotation speed of the servo motor 3 in response to the output change of the rotary encoder 19, the moving speed of the pair of dies 12 with respect to the work 14 is kept equal, and the rotation speed is reduced. Fabrication can be performed correctly and symmetrically. Therefore, an accurate spline can be processed. At this time, there is no need for two 7KW servo motors and two speed control devices for controlling the speed of each servo motor as in the prior art, and a 5KW general-purpose motor, a 7KW servo motor and one Since the device can be constituted only by the speed control device, a significant cost reduction can be realized, and an accurate spline can be manufactured at low cost.

Next, the case of exchanging the dice 12 will be described. The rolling machine has versatility and can roll various kinds of splines, external threads, and the like. At this time, the die 12 needs to be replaced. The mounting accuracy of the dies 12 directly affects the accuracy of the splines and the like, and needs to be mounted with high accuracy.
When the die 12 is attached, the slider 7 driven by the general-purpose motor 2 needs to be stopped at a predetermined position, but it is difficult to stop the general-purpose motor 2 at a predetermined angle.

The rolling machine of this embodiment is a small servomotor 20
When the general-purpose motor 2 and the servomotor 3 are stopped, the small servomotor 20 drives the ball screw 1 to rotate, so that the slider 7 can be accurately stopped at a predetermined position. Furthermore, the servo motor 3
Is rotated, and the slider 7 moved by the ball screw 9 can also be accurately stopped at a predetermined position. With the pair of sliders 7 stopped at predetermined positions, the dies 12 are attached to the dice holders 11 integrated with the respective sliders 7, so that the dies 12 can be positioned with high accuracy with respect to the center position of the work 14.
Since the rotation of the ball screw 1 by the small servomotor 20 is performed when the rolling process is not performed, a small thrust is sufficient. In the present embodiment, a 40 W servomotor is used. The price of the control device for the small servomotor 21 and the small servomotor is one tenth or less of the price of the control device for the large servomotor 3 and the large servomotor.

Next, another embodiment of the present invention will be described. FIG. 3 is a sectional view showing a configuration of a main part of the rolling machine according to the second embodiment. Since the schematic configuration is similar to that of the first embodiment,
Only different parts will be described. A pair of sliders 7
, A pair of racks 26 is fixedly provided. The pair of racks 26 mesh with a pinion 27 located coaxially with the center of the work 14. The pinion 27 includes a bearing 28
And is rotatably attached to the frame 5.

The operation and effect of the second embodiment to which the above configuration is added will be described. In the case where the general-purpose motor 2 is used, no problem occurs in the normal rolling process.
There is a possibility that an unexpected sudden load change will occur in FIG. In this case, the pair of sliders 7 is connected to the pair of racks 26 by one.
By meshing with the two pinions 27, a large overload on the ball screws 1, 9 and the like can be dispersed by the rack 26 and the pinions 27, so that the ball screws 1, 9 and the like may be plastically deformed. Not
The position accuracy of the slider 7 can be maintained.

As described in detail in the above two embodiments, according to the rolling machine of the present invention, the rotation speed of the pair of ball screws 1 and 9 can be made equal by one large servo motor 3, so that the rolling speed is high. The rolling process can be performed with high accuracy, and an inexpensive and high-precision spline can be manufactured.

The present invention is not limited to the above embodiments, but can be applied to various applications. For example, in this embodiment, the independent rotary encoder 19 is used.
Instead of using the independent rotary encoder 19, a rotary encoder 21 attached to the small servomotor 20 may be used. Thereby, the cost can be further reduced. Further, for example, in this embodiment, a three-phase induction motor is used as the general-purpose motor 2, but a torque motor that maintains a constant torque as an output may be used. By using the torque motor, the thrust of the ball screw 1 can be made constant, and it is possible to prevent the ball screw 1 from being overloaded.

[0027]

According to the rolling machine of the present invention, the rotary position of a general-purpose motor for rotating one of the ball screws is detected by a rotary encoder, and the rotational speed of a servo motor for rotating the other ball screw is made uniform. Since the control is performed, the pair of dies can be controlled at a constant speed with respect to the work, so that it is possible to provide an inexpensive rolling machine capable of manufacturing a spline with high accuracy.

In addition, since a small servomotor capable of rotating a ball screw driven by a general-purpose motor is rotatable, the dies can be accurately positioned when the dies are replaced, so that a high-precision spline can be manufactured. Inexpensive rolling machine which can be provided. In addition, since a pair of racks and pinions are provided, even if an unexpected overload is applied to the ball screw, plastic deformation of the ball screw or the like can be prevented, and the accuracy of the rolling process can be maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a rolling machine according to a preferred embodiment of the present invention.

FIG. 2 is a side sectional view of the rolling machine according to the first embodiment.

FIG. 3 is a side sectional view of a rolling machine according to a second embodiment.

FIG. 4 is a block diagram showing a configuration of a control device for a rolling machine.

[Description of Signs] 1,9 Ball screw 2 General-purpose motor 3 Servo motor 5 Frame 7 Slider 12 Dice 14 Work 16,19,21 Rotary encoder 20 Small servo motor 22 Constant speed control device 26 Rack 27 Pinion

Claims (3)

(57) [Scope of request for utility model registration] A pair of ball screws rotatably supported by the frame, a pair of sliders meshing with the respective ball screws and moving in parallel by rotation of the ball screws, and a pair of dies mounted on the respective sliders; In a rolling machine that performs rolling by moving a pair of dies in opposite directions by rotating a ball screw, a general-purpose motor that rotationally drives one of the ball screws, and a servo motor that rotationally drives the other of the ball screws. A rolling machine, comprising: an encoder that detects a rotation angle of the general-purpose motor; and a constant-speed control device that controls the servo motor to rotate at the same speed as the general-purpose motor based on an output of the encoder. . 2. The small-sized servo motor according to claim 1, wherein one of the ball screws rotationally driven by the general-purpose motor is driven to rotate when the general-purpose motor and the servo motor are stopped. Rolling machine characterized by the following. 3. The method according to claim 1, further comprising: a pair of racks fixed to each of the pair of sliders; and a pinion meshing with the pair of racks. Board making.