JPH0318023Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a rotary flow or counterflow type rolling machine.

<Conventional technology> Conventionally, a workpiece is rotatably supported by a tailstock, a pair of dies is mounted on the left and right or up and down sides of the workpiece so as to be movable in parallel, and the pair of dies are moved in parallel and in opposite directions. A rotary flow or counterflow type rolling machine is manufactured that rolls splines, screws, etc. onto a workpiece by moving the machine at a constant speed.

As shown in FIGS. 5 and 6, this type of rolling machine has an upper plate 50 by vertical columns 52 on the left and right.
and a lower plate 51 are fixed at regular intervals, left and right slide stands 53 are vertically fixed between the upper plate 50 and the lower plate 51, left and right sliders 54 are attached to both slide stands 53 so as to be vertically slidable, and both A rolling die 55 is fixed inside the slider 54 via a tool holder, and two hydraulic cylinders 58 are mounted downward on the top plate 50, and the slider 54, that is, the die 55 is moved up and down by the operation of their piston rods. It has a structure that allows Furthermore, a pinion 57 is pivotally supported on the center pin of the tailstock that supports the workpiece, and racks 56 are fixed to the rear portions of both sliders 54 so that both dies 55 are moved in synchronization with each other at a constant speed. There is.

<Problems to be solved by the invention> However, this type of counterflow type rolling machine has a structure in which constant velocity and synchronous control of both dies 55 is performed via a pinion 57 pivotally supported on a center pin of the tailstock. As a result, various problems such as those described below occur, making it impossible to improve machining accuracy.

A backlash inevitably occurs between the pinion 57 and the rack 56, and even if the backlash is adjusted to increase the pressing force between the racks, the pinion 57 will deform into an ellipse, causing both dies to move at a constant velocity.
A considerable error occurs in the synchronous control.

(b) When the right die moves up due to the pullback action of the left hydraulic cylinder, the right die moves downward due to the push-out action of the right hydraulic cylinder, so the thrust of the rising die and the descending die causes the downward movement of the die. The thrust of the two dies, that is, the two sliders 54, becomes significantly large, causing an unbalance of the thrust, and this difference in the thrust of the two dies, that is, the two sliders 54, acts to fluctuate the pinion 57, deforming the pinion shaft, and causing the dies to move at a constant speed and synchronize. This results in considerable errors in control.

The present invention was made to solve the above problems, and the purpose is to provide a rolling machine that can perform rolling with high precision by moving the dies on both sides accurately with constant velocity synchronous control. do.

<Means for solving the problem> To this end, the rolling machine of the present invention has a pair of ball screws rotatably supported on a frame, and a ball fixed to the female threaded portions of both ball screws. A pair of sliders that slide on a guide section arranged along the screw, and two servo motors fixed to the frame to rotate each of the pair of ball screws.
Two speed control units are connected to one servo motor and control the rotational speed of each servo motor based on the input speed command signal, and the two servo motors move a pair of sliders in opposite directions. A position and speed command unit outputs a speed command signal to each of the two speed control units so that the two speed control units are driven at a constant speed in synchronization.

<Operation> With a pair of dies or sliders positioned symmetrically with respect to the workpiece supported by the tailstock, two servo motors are sent from the position and speed command unit to the two speed control units, respectively. A speed command signal is output for driving the sliders in opposite directions at a constant speed in synchronization. Then, each speed control unit operates based on the input speed command signal.
Drive control of two servo motors at constant speed and synchronization. As a result, a pair of ball screws rotate in opposite directions, and a pair of sliders, or dies, fixed to their female threads move along the ball screw at a constant speed in mutual directions, and both dies move toward the workpiece. The workpiece is rotated while being pressed into contact with both sides of the workpiece, and splines and screws are rolled onto the workpiece.

In this rolling machine, a pair of sliders or dies move along the ball screw, so both dies can be moved with a balanced and equal thrust, and a pair of ball screws moves along the ball screw. Each is rotationally driven by a servo motor, and each servo motor is precisely controlled down to the step of one revolution by its respective speed control unit, so a pair of dies synchronize at exactly the same speed and rotate in opposite directions. move to,
Compared to conventional rolling machines using rack and pinions, rolling can be performed with higher precision.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows a front view of the rolling machine, and FIG. 2 shows a half sectional view thereof.

The frame is constructed by connecting the left and right columns 1 and the front and rear heads 2 in a rectangular shape.
A pair of ball screws 3 and 4 are supported at both ends via bearings so as to be rotatable horizontally and in parallel. A slider 5 is attached to the female threaded portions 3a, 4a of the ball screws 3, 4.
6 are each fixed, and both sliders 5 and 6 are
It is slidably supported by groove-shaped guide portions provided inside the columns 1 on both sides via rollers, and can be moved along the ball screws and the column 1 by rotational driving of the ball screws 3 and 4. In addition, both ball screws 3,
The thread pitch of No. 4 is the same, and the female threaded portions 3a and 4a move by the same distance in the same rotation.

Rolling dies 7 and 8 are attached to the pair of sliders 5 and 6 via tool holders on opposing sides, respectively. The workpiece 9 is rotatably supported at its upper and lower ends by the center pin 10 of the tailstock so that it is located vertically at the center of the middle part of the columns 1 on both sides. It is arranged at a position where it is pressed against the processing surfaces of the dies 7 and 8.

A pulley is attached to the front end of the ball screw 3,
A servo motor 12 is fixed to the side of the front head 2 facing forward, and a timing belt 11 is hung between the pulley attached to the main shaft of the servo motor 12 and the pulley of the ball screw 3. It is rotated accurately by a servo motor 12. On the other hand, the left ball screw 4 has a pulley attached to its rear end, a servo motor 13 is fixed to the side of the rear head 2 facing backward, and the pulley attached to the main shaft of the servo motor 13 and the pulley of the ball screw 4 A timing belt 14 is placed between them, and the ball screw 4 is accurately rotationally driven by a servo motor 13 via the timing belt 14. Note that gears or chains may be used instead of the timing belts 11, 14.

As shown in FIG. 2, the ball screws 3 and 4 are arranged horizontally and in parallel, and a pair of drive systems mainly consisting of the ball screws 3 and 4 and servo motors 12 and 13 are driven around the workpiece 9. Since they are located point symmetrically, the force in the expansion/contraction direction applied to the ball screws 3 and 4 and the thrust force of the sliders 5 and 6 are made equal on the left and right sides to maintain a good load balance. Further, by arranging both servo motors 12 and 13 at diagonal positions of the frame, the load balance applied to the frame is maintained well.

The servo motors 12 and 13 are synchronous or induction type that have sufficient torque and can accurately control the rotation speed.
AC servo motors are used, and each motor is equipped with tachogenerators 15 and 16 that output a sine wave signal with a frequency corresponding to the number of rotations.

FIG. 4 shows a block diagram of a control system that controls two servo motors 12 and 13. The control system synchronizes a pair of sliders 5 and 6 from a preset origin position to a predetermined position at a constant speed. A position and speed command unit 20 for two-axis control that outputs a speed command signal to move the object, and each servo motor 12, 13.
The servo motors 22 and 23 are connected to the servo motors 22 and 23, respectively, and control the rotational speeds of the servo motors 12 and 13 based on speed command signals sent from the position and speed command unit 20.

The position and speed command unit 20 converts the distance from the preset origin position to the position where the slider is moved and stopped into the number of pulses (for example, 1
5/1000mm per pulse) and a speed setting section for setting the rotational speed of the motor.
The sine wave signal from 6 is converted into a pulse and input, and based on this position detection signal, each servo motor 12,
A speed command signal (voltage signal) for 13 is output to each speed control unit 22, 23.

The speed control units 22 and 23 control the frequency and voltage using, for example, a voltage source inverter to control the speed of the AC servo motors 12 and 13, and include a converter 24 that converts AC to DC;
A voltage type inverter 25 connected to the output side of the converter 24, and a speed detector 28 that converts the sine wave signals sent from the tachogenerators 15 and 16 into a voltage signal according to the frequency and detects the speed of the motor. A voltage comparison section that compares a voltage signal corresponding to the detected speed sent from the speed detector 28 with a speed command signal sent from the position and speed command unit 20, and outputs a control signal so that the detected speed matches the command speed. 26, and an f/v control section 27 which inputs a control signal from the voltage comparison section 26 and controls the frequency and voltage of the inverter 25 according to the control signal. Moreover, this speed control unit 22,
A pulse converter 29 is provided within 23 for converting the sine wave signals from the tachogenerators 15 and 16 into pulses and transmitting the pulses to the position and velocity command unit 20.

Next, the operation of the rolling machine having the above configuration will be explained.

First, the original positions of the pair of sliders 5 and 6 (dies 7 and 8) are set in the position and speed command unit 20, and the target positions where the left and right dies 7 and 8 pass through the sides of the workpiece 9 and stop are set. Convert the distance to the pulse number and set it, and then set the rotational speed of the servo motors 12 and 13.

Next, the rod-shaped workpiece 9 is vertically set so as to be rotatably supported between the upper and lower center pins 10 of the tailstock, and the start switch is turned on. Then, the two servo motors 12 and 13 start simultaneously and rotate at a constant speed while being synchronously controlled to achieve the rotation speed specified by the respective speed control units 22 and 23. , a pair of ball screws 3 and 4 are rotationally driven, and both sliders 5 and 6 fixed to the screw portions are synchronously moved parallel to each other at a constant speed along the ball screws in opposite directions. In this state, the sliders 5 on both sides,
When the dice 7 and 8 of No. 6 reach the side of the workpiece 9,
The dies 7 and 8 move in opposite directions while pressing their machined surfaces against the surface of the workpiece 9, thereby forming a spline or external thread on the surface of the workpiece 9. Both dice 7 and 8, or sliders 5 and 6, are
After passing the side of the workpiece 9, the servomotors 12 and 13 stop at a preset target position, and then the servomotors 12 and 13 stop.
13 is driven in reverse, so that both dice 7,
8, that is, the sliders 5 and 6 move in the opposite direction, pass the side of the workpiece 9, and return to their original positions.

In this way, both sliders 5 and 6, that is, both dies 7 and 8, are moved simultaneously and at a constant speed by the completely synchronized constant speed operation of the two servo motors 12 and 13, and the rolling process is performed. For example, when rolling an involute spline, it is possible to achieve extremely high processing accuracy with an error of 0.01 mm or less in the tooth thickness.

Note that in the above embodiment, an AC servo motor was used and an inverter was used for the speed control units 22 and 23, but a DC servo motor was used and the speed control unit could be a thyristor Leonard system, a transistor chopper system, or a transistor chopper system. It is also possible to use a thyristor-type power controller.

Further, in the above embodiment, the two ball screws are arranged horizontally and in parallel, but the two ball screws may be arranged in parallel in two stages, upper and lower, or the frame is vertical and the two ball screws are It is also possible to arrange the ball screw vertically. When moving the slider up and down with the ball screw vertical, support the sprocket at a predetermined position on the frame, hang the chain vertically on the sprocket, and attach one end of the chain to the slider.
The other end may be connected to a weight so that the weight of the slider is canceled out, and the thrust of both sliders moving up and down is made equal and balanced.

<Effects of the invention> As explained above, according to the rolling machine of the present invention, the mechanism for moving the dies on both sides at a constant speed does not use a rack or pinion, and two servo motors are electrically operated. Since the drives are synchronized and controlled at a constant speed, there are no errors caused by buck crushing when using racks and pinions, and both dies are moved in perfect synchronization and at a constant speed, resulting in high-precision rolling. Can be processed. Furthermore, since the pair of sliders, that is, the dies are moved in parallel by a ball screw, the rolling thrust of both dies is made equal, and both dies can be accurately moved under the same conditions, allowing highly accurate rolling to be performed.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention.
The figure is a front view of the rolling machine, Figure 2 is its half-sectional plan view, Figure 3 is an enlarged sectional view of Figure 2, Figure 4 is a block diagram of the servo motor control system, and Figure 5 is the conventional one. The front view of the rolling machine in Figure 6 is the − of Figure 5.
It is an enlarged sectional view. 3, 4... Ball screw, 5, 6... Slider, 7, 8... Dice, 12, 13... Servo motor, 20... Position and speed command unit, 22, 2
3...Speed control unit.

Claims (1)

[Claim for Utility Model Registration] A pair of ball screws rotatably supported on a frame, and a sliding guide portion fixed to the female threads of both ball screws and arranged along the ball screws. a pair of sliders, a pair of dies mounted oppositely to the pair of sliders via a tool holder, and a pair of dies fixed to a frame so as to rotate each of the pair of ball screws. two servo motors, two speed control units each connected to the two servo motors and controlling the rotational speed of each servo motor based on the input speed command signal; and the two servo motors. and a position and speed command unit that outputs a speed command signal to each of the two speed control units so that the pair of sliders are driven at a constant speed in synchronization in opposite directions. rolling machine.