JPH0671560A - Automatic centering and center rest device for cylindrical grinding of long work and grinding method therewith - Google Patents

Abstract

PURPOSE:To achieve a job for automation by dispensing with any center rest operation of a skilled labor in the case where such a long work W as being strict in grinding accuracy, especially in roundness is ground with a center rest. CONSTITUTION:A noncircular projection in a preprocess is ground by a synchronous feed between the feed of freely closing a holding diameter of an automatic centering and center rest for positioning so as to stop the advance of a piston rod 32 of a hydraulic cylinder 31 opening or closing this automatic centering and center rest constituted so as to enable two claws 28, 29 to grasp a work W concentrically by means of contact with a cam by a feed screw 37 to be rotated by a numerically controlled servomotor 43 and the infeed of a grinding wheel 9, through the axial movement of a rod 25 with each cam 24 symmetrically. In addition, a fact that the extent of roundness becomes improved is detected by the stabilization of an input variation in a spring motor, and the feed screw is rapidly fed to a forward end position, releasing an engagement with the piston rod 32, then the claws 28, 29 of the automatic centering and center rest are energized in a free closing manner, holding the work, thus grinding takes place.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic centering steady rest device for grinding a long workpiece which is required to have a good working accuracy, in particular, a roundness, and a grinding working method using the device.

[0002]

2. Description of the Related Art Conventionally, when grinding a long workpiece,
The two-point support type steady rest shown in FIG. 6 is often used in order to stop the deflection due to the self-weight of the work and the deflection (escape) due to the grinding force. Further, since the automatic centering steady rest shown in FIG. 7 known in Japanese Patent Publication No. 47-29836 has recently become capable of producing a high-precision steady rest due to its mechanical structure, the rollers 101 and 102 are replaced with pawls for long workpieces. It has been used more often for grinding.

[0003]

The former described in the prior art cannot be adapted to automation because it is a manual operation, and especially the operation for supporting a pre-machined surface having a poor roundness requires an extremely high degree of skill. It has a problem that it costs. The latter is a structure in which the fluid pressure driving means 105 grasps the outer diameter at once,
There was a problem that the non-roundness of the supporting surface was transferred to the ground surface, and a ground surface with good roundness could not be obtained. The present invention has been made in view of the above problems of the conventional technique, and an object of the present invention is to automatically perform NC control until a non-perfect circle of a steady rest of a workpiece can be machined into a perfect circle. (EN) An automatic centering steady rest device capable of changing the gripping diameter of the centering steady rest and thereafter grinding a long work by a normal supporting method by fluid pressure, and a grinding working method using the device. To do.

[0004]

In order to achieve the above object, an automatic centering steady rest device for cylindrical grinding of a long workpiece according to the present invention responds to a change in sliding position of a rod provided with a symmetric cam. An automatic centering steady rest, configured so that a claw that can be opened and closed by contact with the cam together with the rod to concentrically hold a work of different diameter, is detachably provided on the table of the cylindrical grinder, and An NC controlled feed screw member is provided which is provided with fluid pressure driving means for sliding the rod on the frame body and which is engaged so as to restrain the forward movement of the rod by the fluid pressure driving means and is positioned so as to loosen the restraint. Is provided, and when the steady rest grips the work, the engagement is released by the rapid forward advance of the feed screw member.

Further, in the method for grinding a long work using the automatic centering steady rest according to the present invention, the grindstone is lightly contacted by the NC control near the steady rest position of the long work supported by both centers, and the NC control is performed. The feed screw member is manually controlled to perform movement and positioning so as to stop the advance of the fluid pressure driving means for opening and closing the automatic centering steady rest, thereby reducing the gripping diameter of the automatic centering steady rest and making the non-round convexity of the workpiece. The light contact of the part with the automatic centering rest is detected by the intermittent spark or grinding noise coming out of the grindstone, and the manual feed is stopped.
The convex portion is ground by advancing the grindstone by the synchronous control of C and automatically feeding the closing of the automatic centering steady rest, and the disappearance of the convex portion is detected by the stable change of the spindle motor input to detect the fluid. The feed screw member engaged so as to restrain the forward movement of the pressure driving means is fast forward advanced to release the engagement, and the block is supported by the automatic centering steady rest by the force of the fluid pressure driving means. The long workpiece is ground according to a machining program.

[0006]

[Function] The gripping diameter of the automatic centering steady rest that is opened and closed by fluid pressure driving is moved and positioned by the NC control feed screw member so as to stop the force of closing the fluid pressure. The feed is cut in synchronization with this, the support position is ground until there is no convex portion of the non-round shape in the pre-machining, and when the roundness is improved, the feed screw member is fast forward advanced to become the fluid pressure drive means. Is disengaged and returned to the normal fluid pressure driven automatic centering steady rest to perform grinding.

[0007]

EXAMPLES Examples will be described with reference to the drawings. In the cylindrical grinder of FIG. 2, a table 2 is movably mounted on a Z-axis direction guide (not shown) provided on the front side of the bed 1, and the table 2 is mounted on the bed 1 by a Z-axis servomotor 3 fixed to a ball screw. 4 is moved and positioned.
The grindstone base 5 is movably mounted on a guide (not shown) provided on the rear side of the bed 1 in the X-axis direction.
The X-axis servomotor 6 fixed to the position is moved and positioned via the ball screw 7. A grindstone shaft 8 is rotatably supported on the grindstone base 5, and a grindstone 9 is detachably attached to the left end of the grindstone shaft 8. The grindstone 9 is rotated by a grindstone motor 11 via a belt 10.

A headstock 12 and a tailstock 13 are mounted on the table 2.
Are fixed so that their mounting positions can be changed. The center 14 is fixed to the headstock 12 fixed to the headstock 12, and the tailstock 13 is fixed.
A center 16 is detachably attached to the tip of a tailstock shaft 15 that is fitted in the axial direction so that the two centers 14,
A long work W is rotatably supported between the sixteen. A rake 17 is removably attached to the left end of the work W, so that the work W is rotated by a pin 21 planted in a turning gear 19 that is rotated by a spindle motor 18 fixed to the headstock 12. Has become. On the table 2, the automatic centering steady rest unit 22 is placed at the approximate center position of the workpiece W.
It is mounted axially rearward. As shown in FIG. 1, the automatic centering steady rest unit 22 is driven by the axial movement of a rod 25 provided with a cam 24 symmetrically on the right side of a frame body 23 to move the
The roller 27 at the rear end of the arm 20 pivotally supported by 6 comes into contact with the cam 24, and the claw 28 at the tip ends the claw 2 at the tip of the rod 25.
9 is provided with a steady rest having an automatic centering mechanism known from Japanese Patent Publication No. 47-29836, which is configured so as to concentrically grip workpieces having different diameters.

The frame 23 has a hydraulic cylinder 31 and a rod 2
The piston rod 32 of the hydraulic cylinder 31 is fixed to the rear end of the rod 25. Further, a housing 33 is attached to the left end of the frame body 23 concentrically with the hydraulic cylinder 31, and a drive shaft 34 is rotatably supported by the housing 33.
Has a tip formed on the spline shaft 34a. The spline shaft 34a is fitted in a spline hole at the left end of a drive sleeve 36 which is fitted to a bracket 35 concentrically fixed to the right end of the housing 33 so as to be rotatable and axially movable, and a feed screw 37 is provided at the right end of the drive sleeve 36. The left edge of is stuck.

The nut 38 screwed onto the feed screw 37 is
It is fixed to the left end of the hydraulic cylinder 31, and the feed screw 3
7 The flange portion 37a at the right end is rotatably and axially movably fitted into a center hole 32a formed at the left end of the piston rod 32, and the left end surface of the flange portion 37a contacts the right end surface of the lid 39. The piston rod 32 comes into contact with the piston rod 32 to restrain the forward movement thereof. Further, a dog 41 is integrally provided at the right end of the drive sleeve 35, and a limit switch LS1 for confirming the forward end position of the feed screw 37 and a limit switch LS2 for confirming the backward end position of the feed screw 37 are positioned on the support 42 fixed to the hydraulic cylinder 31. It is changeably installed. The drive shaft 34 is a servo motor 4 fixed to the left end of the housing 33.
3 is driven via the decelerator 44.

The pressure oil supplied to the hydraulic cylinder 31 is adjusted in pressure by a regulator 45 from a hydraulic pressure source P and then sent to a solenoid valve 46. Further, the pressure oil is passed through throttles 47 and 48 having check valves in parallel, and the rear chamber and the front chamber. It is supplied to the room. FIG. 3 is a block diagram of the steady rest control system, in which 51 is a program storage unit, 52 is a data setting unit, 53 is a manual pulser for manually generating pulses, and 54 is a drive unit for driving the servomotor 43.
Reference numeral 55 is an input fluctuation detection unit of the spindle motor 18, 56 is a switch for the spindle motor power supply, and 57 is an input connection interface to the data setting unit 52.

Next, the operation of this embodiment will be described.
The long work W is supported between the centers 14 and 15, and the table 2 is moved in the Z-axis to move the grindstone 9 in front of the automatic centering steady rest 22.
Position, the work is rotated to move the grindstone base 5 toward the work in the X-axis direction, and the grindstone 9 is positioned at a position where it lightly contacts the work W. Then, the manual pulsar is operated to rotate the feed screw 37 by the servo motor 43 to release the restraint of the piston rod 32 of the hydraulic cylinder 31 which is biased in the forward direction by the input pulse amount to set the automatic centering steady rest 22. When the claws 28 and 29 are closed and come into contact with the non-round convex portion of the pre-process, it is detected by intermittent sparks or grinding noises emitted from the grindstone 9 and the feeding by the manual pulser is stopped.

Then, the cutting of the grindstone 9 by the X-axis servomotor 6 and the automatic feed of the automatic centering steady stop by the servomotor 43 are synchronized to grind the convex portion. During the grinding process, the non-circular convex portion is intermittently cut, and the input to the spindle motor 18 fluctuates greatly, but as the convex portion is gradually removed and the roundness improves, the input fluctuation disappears. This is detected by the input variation detection unit 55, and the feed screw 37 is advanced to the forward end position at the rapid feed speed, and the piston rod 32
Is disengaged, the work W is supported by the thrust of the hydraulic cylinder 31, and the long work is ground according to the NC program.

The automatic centering steady rest unit 2 of this embodiment
2 has described the example in which the servo motor 43 is provided concentrically with the rod 25, but in order to shorten the longitudinal dimension, the bevel gears 58A and 58A are provided as shown in the structural diagram of FIG.
Using B, the drive axes 59 and 61 are two orthogonal axes,
The servo motor 43 can be provided vertically, and further, as shown in FIG.
Servo motor 4 using gears 62 and 63 as shown in
It is also possible to provide 3 at the misaligned position.

[0015]

Since the present invention is configured as described above, it has the following effects. Closed movement of automatic centering steady rest by fluid pressure drive is moved and positioned so as to be constrained by feed screw member of NC control, and steady feed is achieved by synchronizing the feed of the grindstone and the close-end feed of steady rest. After grinding the support to a perfect circle, the support is gripped by fluid pressure to grind a long workpiece, so the grinding accuracy does not depend on the expert steady rest operation. In particular, most long workpieces with extremely roundness can be automatically ground, which is effective in stabilizing the grinding accuracy and saving labor.

[Brief description of drawings]

FIG. 1 is a sectional view of an automatic centering steady rest of the present embodiment.

FIG. 2 is a top view of a cylindrical grinder equipped with an automatic centering steady rest.

FIG. 3 is a block diagram of an automatic centering steady rest control system.

FIG. 4 is a structural view showing another embodiment of the automatic centering steady rest.

FIG. 5 is a structural diagram showing another embodiment of the automatic centering steady rest.

FIG. 6 is a perspective view of a conventional two-point support type steady rest.

FIG. 7 is a sectional view of a conventional automatic centering steady rest.

[Explanation of symbols]

2 table 9 grindstone 18 spindle motor 14, 16 center 20 arm 22 automatic centering steady rest unit 23 frame 24 cam 28, 29 claw 31 hydraulic cylinder 32 piston rod 37 feed screw 43 servo motor W long workpiece

Claims (2)

[Claims] 1. An automatic structure in which a pawl capable of opening and closing by contact with the cam in response to a change in a sliding position of a rod provided with a symmetrical cam is configured to concentrically grip a workpiece having a different diameter together with the rod. A centering steady rest is removably provided on the table of the cylindrical grinder, and fluid pressure driving means for sliding the rod on the frame body of the steady rest is provided to restrain the advance of the rod by the fluid pressure driving means. A feed screw member of NC control for positioning so as to loosen the restraint by engaging as described above, and when the steady rest grips the work, the engagement is released by the rapid forward advance of the feed screw member. An automatic centering steady rest device for long workpiece cylindrical grinding. 2. A grindstone is lightly contacted by NC control in the vicinity of a steady rest position of a long work supported by both centers, and NC
The feed screw member for control is manually controlled to perform movement positioning so as to stop the advance of the automatic centering steady rest opening / closing fluid pressure drive means to reduce the grip diameter of the automatic centering steady rest to reduce the non-trueness of the workpiece. Light contact of the convex portion of the circle with the automatic centering rest is detected by intermittent sparks or grinding noise coming out of the grindstone to stop the manual feeding, and the advancement of the grindstone by the synchronous control of NC and the automatic The convex part is ground by the self-closing feed of the centering steady rest, and the disappearance of the convex part is detected by the stabilization of the change in the spindle motor input to engage so as to restrain the forward movement of the fluid pressure drive means. The feed screw member is fast-forwarded forward to release the engagement, and the work is supported by the automatic centering steady rest by the force of the fluid pressure drive means to grind the long work according to a machining program. That Grinding method of long workpieces using automatic centering steady rest and symptoms.