JPH0463603A - Thrust automatic regulating tailstock - Google Patents

Abstract

PURPOSE:To perform automatic and accurate regulation of thrust by setting and storing a thrust value in a memory means, converting a thrust value into thrust through detection of generating torque of a drive source, and comparing the set and stored thrust value with a converting thrust value to drive and control generating torque of the drive source. CONSTITUTION:When a tail spindle advancing command is transmitted, a tail spindle control part 22 feeds a tail spindle advancing movement command to a function generating part 27 after calculation of a tail spindle advancing target position, and outputs tail spindle thrust to a thrust comparing part 28. A servo control part 32 stops running of a servo motor 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a tailstock for fixing a cylindrical workpiece.

C. Conventional technology] Conventionally, when fixing a cylindrical workpiece, a conical center hole is drilled in the center of both end faces of the workpiece, and the workpiece is attached to the spindle center fixed to the headstock and the tailstock. The workpiece is held by fitting a tailstock center, which is movable in the direction of the rotational axis, into the center hole and pressing the tailstock center toward the main spindle center.

The tailstock has a main body 1, as shown in FIG.
A tailstock shaft 2 is slidably supported on the main body 1, and a tailstock shaft center 3 is fitted to the front end of the tailstock shaft 2.

An insertion port 2a is opened at the rear end of the tailstock shaft 2, and a sleeve 4 having an inner thread is inserted into the insertion port 2a.
is slidably inserted into the sleeve 4, and a spring pressure adjustment screw 5 is screwed into the sleeve 4.

Furthermore, a spring 6 is compressed between the tailstock center 3 and the spring pressure adjusting screw 5, and the spring 6 biases the tailstock 2 toward the main shaft center.

Further, a connecting body 7 is fitted to the rear end portion of the sleeve 4, and the connecting body 7 has a threaded portion 4 cut at the end of the sleeve 4.
It is fixed by a nut 8 that is screwed into a.

A cylinder 9 is provided in the main body 1 in parallel with the tailstock shaft 2. A 3-position switching solenoid valve 10 is connected to the cylinder 9, and an oil path to the front and rear chambers of the cylinder 9 is connected to the cylinder 9. is connected to the pressure oil side and the drain oil side by a three-position switching solenoid valve 10.

Furthermore, a piston 11 is fitted into the cylinder 9,
The piston 11 is connected to the connecting body 7, and the piston 1
1 and the connecting body 7 are designed to move together.

Further, a limit switch 12 is disposed on the connecting body 7 and positioned so as to be activated when the spring 6 is compressed.

Next, the operation will be explained.

When the SQL A of the three-position switching solenoid valve 10 acts and pressure oil is sent to the front chamber of the cylinder 9, the piston 11 retreats and the tailstock shaft 2 moves to the retreat position.

Therefore, when the workpiece is transferred between the spindle center and the center axis center 3, SQL B is activated and pressure oil is sent to the rear chamber of the cylinder 9.

Then, the piston 11 moves forward, and the connecting body 7 also moves forward together with the piston 11, thereby causing the sleeve 4 to move the tailstock shaft 2 forward via the spring 6.

When the tailstock center 3 comes into contact with the workpiece, the spring 6 is compressed. When the spring 6 is compressed by a predetermined distance, the limit switch 12 comes into contact with the rear end of the tailstock shaft 2 and turns on. .

Then, as the limit switch 12 is turned on, S'OL B of the 3-position solenoid valve 10 stops operating, and the 3-position solenoid valve 10 is in the position shown in FIG.
Pressure oil is not sent to the cylinder 9, and the piston 11 and the connecting body 7
and the sleeve 4 stops advancing.

The limit switch 12 is also activated when the spring 6 is compressed when the forward movement of the center axis 3 is blocked by some kind of drag force, and when the center axis center 3 is not in proper contact with the workpiece or when the workpiece is It also works if the wrong type of workpiece is used.

In addition, the compressed length of the spring is always constant, and in order to change the thrust of the tailstock shaft 2, the amount of protrusion of the spring pressure adjustment screw 5 from the sleeve 4 is changed by rotating the spring pressure adjustment screw 5, and the initial This is done by changing the spring length.

The thrust value is set to a desired thrust by aligning the thrust scale engraved on the knob of the spring pressure adjustment screw 5 with the thrust indicating line.

[Problems to be Solved by the Invention] Since the conventional tailstock is configured as described above, when trying to change the thrust of the tailstock shaft 2, the spring pressure adjustment screw 5
There was a problem in that the thrust force had to be set to the desired value by rotating the engine, which was cumbersome. In particular, when there are a plurality of types of workpieces and the thrust force is different for each workpiece, there is a problem that setting the desired thrust force is even more complicated. Further, since the thrust is set by matching the thrust indication line with the thrust scale engraved on the knob of the spring pressure adjustment screw 5, there is a problem in that it is difficult to accurately set the thrust to a desired value.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a Shinshindai that can automatically and accurately adjust thrust force.

[Means for Solving the Problems] A thrust automatic adjustment tailstock according to the present invention includes a tailstock having a tailstock shaft and a drive source for moving the tailstock shaft in a predetermined direction, and is capable of moving a workpiece. In the centering stand which is held between the spindle center and the center and center, there are a storage means for setting and storing the thrust value when holding the workpiece, a detection means for detecting the generated torque generated by the drive source, and a detection means. a conversion means for converting the detected generated torque into a converted thrust; a comparison means for comparing the thrust value set and stored in the storage means with the converted thrust obtained by the conversion means of the drive source; If the comparison result indicates that the converted thrust value is less than the thrust value set and stored in the storage means, the driving source drives the heart axis in one of the predetermined directions, and the converted thrust value is stored based on the comparison result from the comparison means. and a control means for controlling the drive so as to keep the generated torque of the drive source constant when the thrust value matches the thrust value set and stored in the means, and the workpiece is clamped with a preset thrust force. It is something.

Further, an elastic member may be arranged between the cardiac axis and the drive source.

[Function] The thrust force automatically adjustable tailstock in this invention sets and stores the thrust value when clamping the workpiece by the storage means, detects the generated torque generated by the drive source by the detection means, and The generated torque detected by the drive source is converted into a converted thrust by a conversion means, and the thrust value set and stored in the storage means is compared with a converted thrust value which is a thrust value obtained by converting the generated torque generated by the drive source by the conversion means. compare. Then, the control means drives the driving source to move the cardiac axis in one of the predetermined directions if the converted thrust value is less than the thrust value set and stored in the storage means based on the comparison result from the comparison means.

Further, when the converted thrust value matches the thrust value set and stored in the storage means based on the comparison result from the comparison means, drive control is performed to keep the generated torque of the drive source constant. As a result, the driving source moves the heart axis in a predetermined direction, and the workpiece is clamped with a preset thrust.

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

The tailstock has a main body 1, as shown in FIG.
The main body 1 slidably supports a cardiac axis 2, and a cardiac axis center 3 is fitted onto the front end of the cardiac axis 2.

An insertion port 2a is opened at the rear end of the heart shaft 2, and a sleeve 4 is slidably inserted into the insertion port 2a.

Further, a spring 6 as an elastic member is provided between the center 3 and the sleeve 4, and the spring 6 urges the center 2 toward the center of the main shaft.

Further, a connecting body 7 is fitted to the rear end portion of the sleeve 4, and the connecting body 7 has a threaded portion 4 cut at the end of the sleeve 4.
a l,: Fixed by a screwing nut 8.

Inside the main body 1, a long ball screw 15 whose outer circumferential surface is threaded in parallel with the Shinshin axis 2 is supported by bearings 16 and 17 so as to be rotatable only. It is threadedly engaged with a fixed ball screw nut 18.

Further, a servo motor 20 as a drive source is connected to one end of the ball screw 15 via a coupling 19, and a position encoder 21 as a detection means is mechanically connected to the servo motor 20.

In addition, the thrust automatic adjustment type tailstock has a tailstock shaft control section 22 as shown in FIG.
A data memory 23 serves as a storage means for setting and storing the thrust value when clamping a workpiece, and a program analysis unit 2 analyzes a program read from the program memory 24.
5, a mechanical operation panel 26, a function generation section 27, and a thrust comparison section 28 as comparison means and conversion means are connected.

A tape reader 29 for inputting a part program and a selection circuit 30 are connected to the program memory 24, and an NC operation panel 31 and a data memory 23 are connected to the selection circuit 30.

Further, a servo control unit 32 is connected to the function generation unit 27 and the thrust comparison unit 28 as a conversion means and control means for converting the generated torque into thrust. is connected.

Furthermore, FIG. 3 is a schematic diagram of the mind-brain axis related data stored in the data memory 23, and the mind-brain axis data includes individual data that can be set and stored up to 32 sets for each workpiece, and It consists of common data that is commonly used regardless of the situation.

Next, the operation of this embodiment will be explained.

When selecting and setting the psycho-psychotic axis related data stored in the data memory 23, the operator
Select and set data while looking at the data displayed on the screen.

It is also possible to edit the part program using the NC operation panel 31, in which case it is stored in the program memory 24 via the selection circuit 30.

Note that the part program supplied as a paper tape is read by the tape reader 29 and stored in the program memory 2.
4 is stored.

Next, the forward motion from the retracted state of the cardiac axis will be explained with reference to the flowchart of FIG. 4.

One block of the part program is read out from the program memory 24, analyzed by the program analysis section 25, and checked whether the program instructs the advancement of the mind axis or not using the push button for "advancement of the mind axis" provided on the machine operation panel 26. When is pressed, a cardiac axis advancement command is sent to the cardiac axis control section 22.

Then, the cardiac axis control unit 22 reads a set of cardiac axis data corresponding to the previously instructed cardiac axis data number from the data memory 23 (step 510), and calculates the cardiac axis advancement target position based on the following formula. (Step 511).

"Target position of psychrosis axis advancement" - ``Regular support position'' - ``Regular support width'' / 2 ~ `` Thrust of psychropathy axis'' / ``Spring constant'' Then, the Psychiatric axis control unit 22 determines the target position of advancement of the CG axis and the speed of the CG axis. The function generator 2 sends a command to move the heart axis forward.
7 (step 512), and also outputs the heart-shin axis thrust to the thrust comparison unit 28.

Furthermore, when the thrust comparator 28 receives the cardiac axis forward movement command (step 520), it calculates the 6 push axis command value at that time based on the cardiac axis speed at regular intervals, and applies the 6 push axis command value to the servo. Send to control unit 32 (step 521)
.

Then, the servo control unit 32 reads the position of the heart axis 2 using the position encoder 21 connected to the servo motor 20, and determines the position of the heart axis 2 based on the 6 push axis command values sent at regular intervals. 6. The servo motor 20 is controlled to match the push shaft command value.

Further, a torque command value for the servo motor 20 calculated in the process of controlling the servo motor 20 is sent to the thrust comparison unit 28 .

Then, the thrust comparator 28 receives real-time servo motor torque from the servo controller 32 (step 5).
31), converting the lead of the ball screw 15 into thrust force (
Step 532).

Then, the thrust comparator 28 compares the thrust with the cardiac axis thrust given from the cardiac axis control unit 22 (step 833).

Further, when the value obtained by converting the servo motor torque into thrust becomes 6 push shaft thrusts or more, a thrust coincidence signal is sent to the function generating section 27 (step 534).

Then, the function generating section 27 immediately stops generating the function upon receiving the thrust matching signal (step 523), and the 6 push shaft command value sent to the servo control section 32 is fixed to the value at the moment when the thrusts match, and the servo motor 20 stops rotating.

At this time, the coupling 1 is rotated by the rotation of the servo motor 20.
The ball screw 15 rotates via the ball screw nut 18 and the connecting body 7, and the sleeve advances via the ball screw nut 18 and the connecting body 7.

The spring 6 is not compressed until the center axis 3 comes into contact with the workpiece, and the center axis 2 and center 3 move forward together with the sleeve 4.

At this time, the torque of the servo motor 20 is only equivalent to the frictional force, and the value converted into thrust is small compared to the axial thrust, so the thrust comparator 28 does not generate a thrust coincidence signal.

Furthermore, when the center 3 moves forward and comes into contact with the workpiece, the forward movement of the center 2 and center 3 stops, but the sleeve continues to move forward, so the spring 6 begins to be compressed and reaches its compressed length. The torque of the servo motor 20 increases proportionally.

Then, as the compression of the spring progresses and the spring force matches the Shinshin shaft thrust, the servo motor 20 generates a torque corresponding to the spring force, and the value obtained by converting the servo motor torque into thrust is 6
The thrust comparator 28 generates a thrust coincidence signal (step 534), and outputs this thrust coincidence signal to the function generation section 27.

Furthermore, upon receiving the inference match signal, the function generator 27
Step 523) to stop the function generation, servo motor 2
Since the rotation of the sleeve 4 also stops, the forward movement of the sleeve 4 also stops.
The workpiece is clamped with a predetermined thrust.

In addition, in the above-mentioned embodiment, explanation was given using an example in which the spring 6 was arranged between the tailstock shaft 2 and the sleeve 4, but the spring 6
If the tailstock shaft 2 is not equipped with the following, after the tailstock 2 advances a predetermined distance and the workpiece is held between the main shaft center and the center shaft center 3, the servo control unit 32 converts the torque generated by the servo motor 20 into thrust. By continuing to drive and control the servo motor 20 to a value that matches the thrust of the 6 push shafts, the workpiece is always held with a predetermined thrust.

In this way, the spring 6 can be omitted and the number of parts can be reduced.

[Effects of the Invention] As explained above, according to the present invention, the thrust force for clamping the workpiece is set and stored in advance, and when the heart axis moves forward, the thrust force is automatically adjusted to adjust the spring pressure. This eliminates the trouble of rotating the shaft and setting the desired thrust.
Further, the thrust value can be set accurately by setting the thrust value using a specific numerical value.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a control system of an automatic thrust adjustment type tailstock according to an embodiment of the present invention, and FIG. 2 shows a control system configuration of an automatic thrust adjustment type tailstock according to an embodiment of the invention. FIG. 3 is a schematic diagram of the heart-shin axis relationship data, FIG. 4 is a flowchart showing the operation of the present invention, and FIG. 5 is a sectional view showing the heart-shin stand of a conventional machine tool. 1... Shinshindai 2... Tailstock shaft... Servo motor... Position encoder... Data memory... Thrust comparison section Servo control section

Claims (2)

[Claims] (1) In the tailstock, which includes a tailstock having a tailstock shaft and a drive source for moving the tailstock shaft in a predetermined direction, the workpiece is held between the spindle center and the tailstock shaft center. a storage means for setting and storing a thrust value when clamping a workpiece; a detection means for detecting the generated torque generated by the driving source; a conversion means for converting the generated torque detected by the detection means into a converted thrust; Comparison means for comparing the thrust value set and stored in the storage means with the converted thrust obtained by the conversion means of the drive source, and the thrust that is set and stored in the storage means, and the converted thrust value is determined by the comparison result from the comparison means. If the value is less than the value, the drive source drives the tailstock to move the tailstock in one of the predetermined directions, and the drive is performed when the converted thrust value matches the thrust value set and stored in the storage means based on the comparison result from the comparison means. 1. A thrust automatically adjustable tailstock comprising: a control means for controlling the drive so as to keep the torque generated by the source constant, and clamping a workpiece with a preset thrust. (2) The thrust automatically adjustable tailstock according to claim (1), further comprising an elastic member disposed between the tailstock shaft and the drive source.