JPH0379151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a grinding method using an NC-controlled work rest in an NC grinding machine.

Conventional technology Generally, work rests are used to grind workpieces with low rigidity with high precision and efficiency.
This work rest can be fixed or hydraulic.
An automatic tracking type using electricity is used. However, all of these devices have special specifications unique to specific workpieces, requiring great versatility and requiring skill to adjust the devices. Conventionally, this was determined by placing the horizontal shoe and lower shoe of the rest on a workpiece or master that had been finished to exact size, touching an indicator on each side on the opposite side, and finding the position where the shoe would contact the master. Further, since the forward movement of the lower shoe is based on a rest axis parallel to the rest axis of the horizontal shoe, a relieving mechanism is required. Furthermore, there was the inconvenience of adjusting the shoe wear correction by setting the master each time. Further, the advance amount of the shoe must be adjusted using simultaneous adjustment knobs for the horizontal shoe and the lower shoe, and the amount of push must be adjusted individually using fine adjustment knobs, which is time-consuming. In addition, these adjustment mechanisms had to be provided.

Problems to be Solved by the Invention In order to fully utilize the functions of the work rest, the above-mentioned numerous adjustments must be made, which is a troublesome task.

Measures to solve the problem: Before grinding, the lower shoe touch sensor and the horizontal shoe touch sensor, which are embedded in the center fitting shaft, are aligned with the origin using a reference gauge with a reference hole installed concentrically with the center fitting shaft. The reference origin is aligned with the center line, and the horizontal view of the work rest is controlled independently by NC.
The feed of the lower shoe is carried out synchronously based on the cutting feed program of the grinding wheel, or is carried out variably based on the input data, and the touch sensor for the lower shoe and the touch sensor for the horizontal shoe are used to adjust the horizontal feed at any time during the grinding process. By correcting the origin of the shoe and the lower shoe, it is possible to automatically correct shoe wear and thermal displacement of the machine body.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. In Figures 1, 2, 3, and 4, a lower whetstone stand 2 is provided near the rear of the upper surface of the bed 1, and a whetstone stand 3 is slidable on the sliding guide surface in the front and back direction on the lower whetstone stand 2. The female thread on the lower surface of the grindstone is screwed into a feed screw 4 which is rotatably supported on the lower grindstone stand 2. The feed screw 4 is rotated and its position is controlled by a motor 6 with a detector 5 fixed to the rear part of the lower grindstone stand 2.

A whetstone shaft is rotatably supported on the whetstone head 3 in a direction perpendicular to the movement direction of the whetstone head, and a whetstone 7 is fixed to one end of the shaft, and a pulley 8 is fixed to the other end of the shaft.
The whetstone shaft is rotated via a belt placed between a motor 9 placed on a whetstone head 3 and a pulley 10 . A cover 11 for the grinding wheel 7 and a grinding fluid supply pipe 12 are attached. A sliding guide surface is provided on the front side of the upper surface of the bed 1 in parallel with the grinding wheel shaft.A carriage 13 is placed on this sliding guide surface, and a feed screw 14 whose female thread on the lower surface is rotatably supported on the bed 1.
It is screwed together. This feed screw 14 is rotated by a motor 16 with a detector 15 fixed to the side of the bed 1.

On the upper surface of the carriage 13, the table 17 is the workpiece W.
It is mounted and fixed so that it can rotate slightly on a horizontal plane to correct the taper. A headstock 18 having a kerf drive 19 and a center 20 is fixed to the left end of the table 17, and a tailstock 23 having a center 21 and a tailstock shaft 22 movable in the axial direction is fixed to the right end.
The above is a well-known grinding machine.

The main body 31 of the work rest 30 is fixed to the front surface of the bed 1 at a position facing the grindstone 7, and has a horizontal shoe 28 made of a wear-resistant material that receives the opposite side of the grinding side of the workpiece W gripped by the centers 20 and 21. A horizontal shoe guide shaft 32 is supported so that it can only slide horizontally, is supported on the main body 31 so that it can only rotate, and is threadedly engaged with a feed screw 33 that is connected to the output shaft of a motor 35 equipped with a detector 34. It is moved forward and backward by the rotation of the feed screw 33. In addition, an L-shaped lower shoe guide shaft 36, which has a lower shoe 29 made of wear-resistant material on the upper surface that receives a slight deviation from the grinding wheel on the lower side of the workpiece W, is parallel to the line connecting the contact point of the lower shoe and the center of the workpiece. It is supported on a shaft so that it can only slide in the direction of the
It is threadedly engaged with a feed screw 37 which is rotatably supported on the shaft 1. A bevel gear 38 is attached to the shaft end of the feed screw 37.
is fixed, and this bevel gear 38 meshes with a bevel gear 41 at the output shaft end of a motor 40 with a detector 39 provided on the side surface of the main body 31.

In order to align the origin of each shoe of this invention, the outer periphery of the center fitting portion of the tailstock shaft 22 has a tapered surface 42 that supports the reference ring gauge M concentrically with the center of the hole of the center 21 and a surface perpendicular to the axis. Flange 4
3 is provided, and a touch sensor 4 described later is provided.
A tapered hole of a reference ring gauge M whose inner diameter is used as a reference for aligning the origin of the rings 7 and 48 fits into the tapered surface 42. Bracket 4 protruding from the outer periphery of flange 43
4 supports a pipe 45 branched from the grinding fluid supply pipe, and a nozzle 46 facing the center is attached to the tip to clean the outer periphery of the reference ring while preventing dimensional changes between the workpiece and the reference ring due to thermal expansion. do. Furthermore, touch sensors 47 and 48 are embedded in the tapered fitting portion of the tailstock shaft 22 at a position where the horizontal shoe 28 can contact and a position where the lower shoe 29 can contact, respectively. A signal is sent to the device.

And the control of the grindstone head 3 is by the tape 51 of the NC device.
The reading command value of the tape reader 52 that reads the data is sent to the function generator 53, and a function that draws the commanded speed and trajectory is input to the position control 54 in real time, and the comparison circuit 55 calculates the position from the detector 5. The detected value is compared with the detected value, and the value is inputted to the speed control section 56 and sent to the detector 5 in the comparison circuit 57.
The current command is compared with the detected speed value of the current command and input to the servo amplifier section 58, where the power is amplified and output to the motor 4 to control the cutting position of the grindstone head 3.
Similarly, the carriage 13 is controlled by the command value read by the tape reader 52 and the detected value of the detector 15 by the function generator 53, position controller 55, speed controller 57,
The servo amplifier unit 58 calculates the output using time sharing and provides the output to the motor 16 to perform positioning control. Further, the horizontal shoe 28 and lower shoe 29 of the work rest 30 are connected to the tape leader 5.
The read command value of 2 is calculated by time shearing in the function generator 53, position controller 54, and speed controller 56, and the amplified output is given to each motor 35, 40 by the servo amplifier 58. The output of the detector 34 is compared with the output of the detector 5 of the grinding wheel head 3 in a comparison circuit 55 of the position control 54, and also compared in the comparison circuit 57 of the speed control section 56. It is based on the movement of Similarly, the output of the detector 39 of the lower shoe 29 is compared with the output of the grinding wheel head 3 detector 5 in the comparison circuit 55 of the position control section 54, and is also compared in the comparison circuit 57 of the speed control section 56. The movement is also based on the movement of the grinding wheel head 3, and depending on the grinding program, the work rest 3
0 is being driven.

Data necessary for grinding wheel cutting and positioning is written on the tape 51 of the control device.In addition, commands to the horizontal shoe 28 and lower shoe 29 of the work rest 30 based on the grinding program are also written. In the case of sizing, the position data of the position at the end of rough grinding, the position at the end of fine grinding, and the sizing position are stored, and the output positions of the same 1P, 2P, and 3P signals of the direct sizing device (not shown) are stored. If the amount of deviation between the command value data and the directly sized 1P, 2P, and 3P signal positions exceeds an allowable value, an alarm will be output.

Operation will be described with reference to FIG. 6 which shows a sequence chart of the grindstone 7 and work rest 30, and FIG. 5 which shows a diagram of the grindstone incision and work rest movement.

Before machining, in order to align the origin of the touch sensors 47, 48, the reference gauge M is fitted coaxially to the outer tapered surface of the center fitting part of the tailstock spindle, and the output position of the touch sensors 47, 48 at this time is checked. Then, the position of the carriage 13 is controlled to align the touch sensors 47 and 48 of the tailstock 23 with the horizontal shoe 28 and lower shoe 29 of the work rest 30. Then, the motors 35 and 40 are driven to advance the horizontal shoe 28 and the lower shoe 29, and when the touch signal is output, the positions are memorized and stopped to perform origin alignment. Based on the command value read from the tape 51 by the tape reader 52, a function generating section 53 generates a function that draws a commanded trajectory at a commanded speed, and the function is amplified by the position control section 54 and speed control section 56 at the servo amplifier 58. The output of each motor 6,
Sent to 16, 35, 40.

First, in the case of back-off, grindstone head 3
is in the backward position, the motor 6 is rotated at high speed, and the motor 6 is moved forward to position by rapid traverse to a predetermined position, and then the motor 6 is moved forward by gear feed at a reduced speed, and a spark-out is performed to remove the eccentricity of the workpiece W, and then Rough grinding feed is performed, rough grinding is performed, and spark out is performed for a predetermined time. When the spark-out is completed, the grindstone head 3 retreats by a predetermined amount and leaves the workpiece W once. At this point, the grinding force that has been acting up until now is removed and the deflection of the workpiece W returns.
At the back-off completion position, a positioning command is issued to the work rest 30, and the horizontal shoe 28 and the lower shoe 29 are positioned and sent forward to the current value of the grindstone + the preceding amount. When the work rest 30 is positioned, the grinding wheel 3 is separated from the workpiece W by retreating, so after rough grinding, the workpiece W is moved to the horizontal shoe 28 and the lower shoe 2.
It will be pressed by the advance amount of 9. The grindstone 7 stops slightly at the back-off position while the work rest 30 is moving forward, and starts grinding at a speed slower than rough grinding when the positioning of the work rest is completed and a rough grinding command is issued in the grinding program. When using a direct sizing device, the device is also positioned forward. The horizontal shoe 28 and lower shoe 29 of the work rest 30 are each input from a servo amplifier 58 in which the output of the detector 5 of the grinding wheel head 3 is input together with the detector 34 of the horizontal shoe 28 and the detector 39 of the lower shoe 29 and calculated. The respective motors 35 and 40 are driven by the output and are moved forward following the coarse grinding feed of the grindstone 7. As rough grinding progresses, the feed of the grinding wheel 7 is stopped and sparked out due to the 1P signal of the direct sizing device or the rough feed amount data of the indirect sizing device, and the horizontal shoe 28 and lower shoe 29 of the work rest 30 are stopped at the same time. be done. When the spark-out for a predetermined period of time is completed, the grinding wheel 7 is given a fine grinding feed, and the horizontal shoe 28 and the lower shoe 29 are given a feed that follows the cut of the grinding wheel 7. Fixed size position data is given to the horizontal shoe 28 and the lower shoe 29, and the respective detectors 34,
When the value matches the current value output from 39, the feeding of the work rest 30 is stopped. Horizontal shoot 28,
Since the lower shoe 29 has a leading amount added to it and has preceded the grinding wheel 3, it stops before the grinding wheel 7 stops and becomes ready to spark out. As the fine grinding feed progresses, the feed of the grinding wheel 7 is stopped by the 2P signal from the direct sizing device or the fine feed amount data from the indirect sizing device, and spark-out is performed. The amount of uncut material is ground by spark-out, and the 3P of the direct sizing device is
A signal is output or the spark-out timer data causes the grinding wheel 7, direct sizing device and horizontal shoe 2 to
8. The lower shoe 29 is retracted. The grindstone 7 is retreated to the return end position, but the horizontal shoe 28 and the lower shoe 29 are stopped at that position because the work rest follow-up cutback position data is input on the way.

Next, in the case of no back-off, after rough feeding of the grinding wheel 7, when the grinding wheel enters spark-out by command, the horizontal shoe 28 and lower shoe 29 of the work rest 30 display the current value of the grinding wheel head for positioning the work rest - escape amount (- The data of the advance amount) is inputted, and each moves forward and stops in front of the workpiece W by the amount of escape. Therefore, the work rest 30 does not come into contact with the workpiece W. When the forward positioning of the work rest and the spark-out for a predetermined time are completed, the grindstone 7 is fed for rough grinding from that position. On the other hand, the horizontal shoe 28 and the lower shoe 29 of the work rest 30 move forward at a faster speed than the rough grinding feed of the grinding wheel 7 and touch the workpiece W on the way because the feed that follows the grinding wheel head feed speed is multiplied by the feed rate percentage. Push in as soon as they make contact. Similarly to the above, spark-out is performed for a predetermined time at the end of rough grinding feed using the 1P signal or rough feed amount data, and both the grinding wheel 7 and the work rest 30 are stopped.

When the spark out is finished, grinding wheel 7 is moved with fine grinding feed.
is fed, and the horizontal shoe 28 and lower shoe 29 are fed faster by the feed rate while following the grindstone feed. Similarly, the grinding wheel is stopped by the 2P signal or the dense feed amount data. Workrest fixed size position data is input to the horizontal shoe 28 and the lower shoe 29, and when the data matches the current values from the detectors 34 and 39, respectively, feeding of each shoe is stopped. The grinding wheel 7 is delayed and similarly stopped by the 2P signal or dense feed amount data and enters spark-out. Spark-out is performed, and the grinding wheel 7, sizing device, horizontal shoe 28, and lower shoe 29 are similarly retracted by the 3P signal or spark-out timer data. The work rest 30 is inputted with the backward position data with the tracking off halfway, and when the current values of each shoe match, the return is stopped. When the grinding process is performed, the position of the carriage 13 is controlled and the work rest 30 and touch sensors 47, 4 are
8, the origin of the horizontal shoe 28 and the lower shoe 29 is corrected, and wear of the shoe is automatically corrected, as well as thermal displacement of the machine body.

Effects As described in detail above, the present invention aligns the origin using an inner diameter reference gauge that has a lower shoe touch sensor and a horizontal shoe touch sensor embedded in the tailstock shaft concentrically with the tailstock shaft, and aligns the reference origin on the center center line. The horizontal and lower shots of the matching work rest are independently NC-controlled, and each show is controlled by the grinding program based on the output of the detector on the grinding wheel head.
A workpiece-specific shoe and master gauge are not required, and manual adjustment of origin correction can be eliminated. In addition, since it can perform steady rest work with multiple diameters, it is not limited to specific workpieces and has increased versatility, making it possible to perform high-precision, high-efficiency automatic machining of long multi-stage shafts. Furthermore, it has the effect that shoe wear correction and thermal displacement correction of the machine body are automatically performed.

[Brief explanation of drawings]

Fig. 1 is an explanatory side view of the grinding machine, Fig. 2 is a front view thereof, Fig. 3 is an explanatory drawing of the touch sensor embedded part, Fig. 4 is an illustration of setting the origin of the shoe, Fig. 5 is a cut of the grindstone, FIG. 6, which is a diagram showing the movement of the work rest, is a sequence diagram of the grindstone and the work rest. 3...Whetstone stand, 7...Whetstone, 5, 15, 34,
39...detector, 6,16,35,40...motor, 13...carriage, 17...table, 22
... Tailstock shaft, 47, 48 ... Touch sensor, 52
...Tape reader, 53...Function generator, 54...
...position control section, 56 ... speed control section, 58 ... servo amplifier, 55, 57 ... comparison circuit.

Claims (1)

[Claims] 1 Before the grinding process, align the origin with a reference gauge having a reference hole installed concentrically with the center fitting shaft, and set the touch sensor for the lower shoe and the touch sensor for the horizontal shoe buried in the center fitting shaft, and set the reference origin to the center. The feed of the horizontal and lower shots of the work rest, which are aligned on the center line and whose positions are independently controlled by NC, are performed synchronously based on the cutting feed program of the grindstone, or are performed variably based on input data. , the origin of the horizontal shoe and the lower shoe is corrected at any time during the grinding process by the touch sensor for the lower shoe and the touch sensor for the horizontal shoe, thereby making it possible to automatically correct shoe wear and thermal displacement of the machine body. N.C.
Grinding method using controlled work rest.