JPH01234162A - Processing method - Google Patents

Abstract

PURPOSE:To control a cutting action for a work properly and increase the processing efficiency and processing precision for the work by controlling the magnetic force of electromagnets of a magnetic shaft bearing spindle electrically. CONSTITUTION:By electrically controlling the magnetic force of radial electromagnets 15, 16 by a magnetic shaft bearing controller so as to displace a rotary spindle 13 from a target position before a change to a target position after the change while detecting the position of the rotary spindle 13 in the diametric direction by position detectors 34, 36, so a grindstone 41 is operated to perform a cutting action to the work. As a result, the cutting action can be adjusted finely electrically, and its responsiveness can be improved extraordinarily, thereby an inner hole of a work can be cut and processed to have a predetermined roundness securely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a processing method for a processing machine equipped with a magnetic bearing spindle.

[Summary of the invention]

The present invention improves the machining efficiency and machining accuracy of the workpiece by changing the target position of the rotary spindle in the magnetic bearing spindle and causing the tool to cut into the workpiece, regardless of the mechanical error or responsiveness of the processing machine. The aim is to improve

[Conventional technology and problems]

In conventional processing machines, such as grinders, cutting into a workpiece with a grinding wheel is performed by moving the work table on the workpiece side or the grinding wheel table on the grinding wheel side to create a relative position between the workpiece and the grinding wheel. was. Furthermore, in a grinding machine, a cutting operation such as overfeed or retraction may be performed in the middle of cutting in order to improve the processing efficiency and processing accuracy of the workpiece. Overfeed is momentary excessive cutting.
Retraction is a momentary retreat of the cut. All of them are small in size and can be done instantaneously. Conventionally, such subtle overfeed or retraction has been performed by moving the work table or grindstone table.

However, work tables and grindstone tables have large masses, and the motors, ball screws, etc. that drive them inevitably have mechanical errors, and the table bearings, oil seals, etc. r! l Rubbing resistance Responsiveness deteriorates due to the inertia of a table with a large mass. For this reason, it is not possible to effectively perform the above-mentioned overfeed or traction, which requires high precision and excellent responsiveness, and therefore it is not possible to sufficiently achieve the desired improvement in machining efficiency and machining accuracy of the workpiece. The problem was that it couldn't be done.

[Means for solving problems]

Therefore, in order to solve the above-mentioned problems, the processing method according to the present invention includes a rotating spindle with a tool provided at the end, an electromagnet that levitates this rotating spindle by magnetic force and supports the bearing, and a radial direction of the rotating spindle. A magnetic bearing spindle comprising: a position detecting means for detecting a position; and a magnetic bearing control device inputting a signal from the position detecting means to control the magnetic force of the electromagnet to maintain the rotary spindle at a target position. The processing machine is characterized in that the tool is caused to perform a cutting operation into the workpiece by changing a target position in the radial direction of the rotating spindle.

[Effect]

According to such a machining method, while the position detection means detects the radial position of the rotary spindle, the magnetic bearing control device displaces the rotary spindle from the target position before change to the target position after change. By electrically controlling the magnetic force of the electromagnet, the tool performs the cutting operation of the workpiece, making it possible to make minute adjustments electrically and dramatically improving responsiveness, eliminating mechanical errors in the grinding machine. It is possible to reliably improve workpiece machining efficiency and machining accuracy, regardless of the quality or responsiveness.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1 to 6 are diagrams showing a first embodiment of the processing method according to the present invention.

In the internal grinding machine 10 shown in FIG. 1, 11 is a magnetic bearing spindle, and this magnetic bearing spindle 11 is fixedly supported on a grindstone table 14. As shown in FIG. The grindstone table 14 can be slid in the axial direction along a rail 17 on a bed frame 19 by a motor 23. 2
0 is a chuck device that fixedly supports a work 21, and the work 21 fixed to this chuck device 20 is moved by a motor 2.
4, and the chuck device 20 is fixedly supported on a work table 22.

The work table 22 is mounted on the rail 1 on the bed frame 19.
8 in a direction perpendicular to the grindstone table 14 by a motor 25.

Next, in the magnetic bearing spindle 11 shown in FIG.
Reference numeral 12 denotes a main body that constitutes the outer shape of the main body 12. A rotary spindle 13 is disposed on the axis of the main body 12. The rotary spindle 13 is magnetically levitated and supported by bearings around both ends of the zero-rotation spindle 13. Radial electromagnet 15
．． A motor 28 for rotationally driving the rotary spindle 13 is provided at the intermediate portion in the length direction of the zero-rotation spindle 13 provided on the main body 12 side, and a motor 28 for driving the rotary spindle 13 to rotate the shaft of the rotary spindle 13 via a flange portion 30 of the rotary spindle 13. A pair of axial electromagnets 31 and 32 for regulating displacement in the main body 1
It is provided on the second side.

A position sensor 34 that detects the radial position of the rotating spindle 13 is provided on the main body 12 near the radial electromagnet 15, and a position sensor 34 that also detects the radial position of the rotating spindle 13 is provided near the radial electromagnet 16. 35 is provided on the main body 12 side. In addition, the rotating spindle 1
A position sensor 36 for detecting the axial position of the rotary spindle 13 is provided on the main body 12 near a step 13a formed at one end (left end in the figure) of the rotary spindle 13.

When the radial electromagnets 15 and 16 are de-energized and the magnetically levitated blade of the rotary spindle 13 is lost, a small diameter portion is formed around the small diameter portion 13b on one end side of the rotary spindle 13 and the small diameter portion 13c on the other end side, respectively. Protective bearings 38 and 39 that directly support the rotary spindle 13 via 13b and 13c are provided on the main body 12 side. A cylindrical grindstone 41 for grinding the workpiece 21 is provided.

As shown in FIG. 3, the radial electromagnets 15 and 16 are located near the top, bottom, left and right sides of the rotating spindle 13, respectively.
Total of 4 each (15a to 15d.

16a to 16d) are provided. Further, as shown in FIG. 4, the magnetic bearing spindle 11 is connected to a magnetic bearing control device 47.
Further, this magnetic bearing control device 47 is controlled by:
Work table 2 that gives main cutting action to work 21
The servo driver 27 of the motor 25 that drives the motor 2 is program-controlled by the CPU 50 via D/A converters 55 to 57.

Such a magnetic bearing spindle 11 is equipped with a position sensor 34.
, 35 detect the radial position of the rotary spindle 13, and the magnetic bearing control device 47 controls the magnetism of the electromagnets 15, 16 so as to displace the rotary spindle 13 from the target position before the change to the new target position after the change. The force can be controlled electrically. For example, the third
By electrically controlling the magnetic forces of the radial electromagnets 15b, 16b on the left side in the figure and the radial electromagnets 15d, 16d on the right side, the rotating spindle 13 is translated by a predetermined distance to either the left or right in the figure while rotating. can be done.

Next, a method of grinding using the internal grinding machine 10 equipped with such a magnetic bearing spindle 11 will be described. First motor 2
4 rotates the workpiece 21 of the chuck device f20, and rotates the rotating spindle 13 of the magnetic bearing spindle 11.
6. Then, the CPU 50 rotates the motor 25 via the servo driver 27. Chuck device 2
The workpiece 21 of No. 0 is moved in its radial direction, the workpiece 21 is cut into the grindstone 41, and the grinding operation begins.

After the encoder 52 detects the rotation of the motor 25 and performs pulse shaping and direction determination of the output signal from the encoder 52, the position counter 48 calculates the cutting position, and the CPU 50 then determines whether or not it is currently in the coarse grinding feed range. (Pl of the fifth factor). When the CPU 50 determines that the current feed rate is within the rough grinding feed range, the CPU 50 checks the memory such as the ROM 51 and selects the most suitable method to improve the machining efficiency and machining accuracy of the workpiece 21 at that time. An appropriate target overfeed amount and target retraction amount are set (P2 in the figure).

Next, the CPtJ50 generates a ramp wave corresponding to these amounts (P3 in the same figure), and electrically converts the magnetic force of the radial electromagnet 15, 16 through the D/A converter 55, 56 and the magnetic bearing control device 47. By controlling the rotating spindle 1
As shown in section A1 of diagram A in FIG. ), the above-mentioned overfeed and retraction cutting operations are performed (P5 in the same figure), and line B in FIG. 6 shows the motor 25. The main cutting positions of the work 21 by the work table 22 are shown, and B1
indicates the rapid feed range, B2 indicates the coarse grinding feed range, and B3 indicates the fine grinding feed range.

Next, the CPU 50 determines whether or not the grinding is completed, and if it is not completed, returns the control procedure to the start side, and again determines whether or not it is currently in the coarse grinding feed range.
l) If it is determined that this is not the case based on the signal from the position counter 48, it is further determined whether or not the present condition is within the fine polishing feed range (P6 in the same figure).When it is determined that the present condition is within the fine polishing feed range, the CPU 50 By checking with the memory such as the ROM 51, the most appropriate target overfeed amount and target retraction amount are set at that time to improve the machining efficiency and machining accuracy of the workpiece 21 (P7 in the figure).

Next, the CPU 50 generates a ramp wave corresponding to these amounts (P3 in the figure) in the same manner as described above, and the D/A converters 55, 5
6. Radial electromagnet 15 via magnetic bearing control device 47
．． By electrically controlling the magnetic force of 16, the target position in the radial direction of the rotating spindle 13 can be adjusted to the position A in the diagram A in FIG.
As shown in part 2, the rotary spindle 13 is momentarily changed in the forward and reverse directions to displace it (P4 in the same figure), and the above-mentioned overfeed and retraction cutting operations are performed (P5 in the same figure); In this way, the rotating spindle 13 performs appropriate overfeed and retraction cutting operations in the rough grinding feed range or fine grinding feed range.
By performing this by the displacement of
It is possible to reliably improve the machining efficiency and machining accuracy of the workpiece 21, regardless of the mechanical error or the superiority or inferiority of response.

A second embodiment of the present invention is shown in FIGS. 7 to 9. As shown in FIG.
A sizing device 45 that detects the machining dimensions of the workpiece 21 and inputs a sizing signal to the CPU 50 via the I10 boat 53.
It has been established. Then, the sizing device 45
When the workpiece 1 reaches the first predetermined dimension in the course of being machined in the coarse grinding feed range, the first shimmit signal is output; A second Schmitt signal is output when the limit is not reached.

In this second embodiment, the CPU 50 rotates the motor 25 via the servo driver 27, moves the workpiece 21 in the radial direction to make a cut, and after starting the grinding operation, determines the machining dimensions of the workpiece 21. The size device 45 detects,
When the machining dimension reaches the first predetermined dimension, the sizing device 45 outputs the first Schmit signal to the I10 boat 53 (21 in FIG. 8). When input, the CPU 50 outputs RO
Work 21 is checked at that time by checking with the memory of M51 etc.
The most appropriate target overfeed amount and target retraction l are set to improve machining efficiency and machining accuracy (P2 in the same figure).

Next, the CPU 50 generates a ramp wave corresponding to these amounts (P3 in the same figure), and electrically converts the magnetic force of the radial electromagnet 15, 16 through the D/A converter 55, 56 and the magnetic bearing control device 47. By controlling the target position in the radial direction of the rotary spindle 13, the target position in the radial direction of the rotary spindle 13 is instantaneously changed in the forward and reverse directions as shown in section A1 of the diagram A in FIG. ), perform overfeed and retraction cutting operations in the same manner as in the first embodiment (P5 in the same figure), line B in FIG. 9 corresponds to the machining dimensions of the workpiece 21 detected by the sizing device 45. These show sizing signals, of which B1 shows the dimensional change in the rough grinding feed range, and B2 shows the dimensional change in the fine grinding feed range.

Next, the CPU 50 determines whether or not the grinding is completed, and if it is not completed, returns the control procedure to the start side, and again determines whether or not the first grinding signal has been output, and If it is determined from the signal that this is not the case, it is further determined whether or not the sizing device 45 has outputted the second Schmitt signal. When the machining dimension of the workpiece 21 reaches the second predetermined dimension, the sizing device 45 outputs a second tightening signal to the I10 boat 53 (P6 in the same figure).
When the second Schmitt signal is input to the I10 boat 53 in this way, the CPU 50 compares it with the memory such as the ROM 51 and selects the most appropriate target overfeed for improving the machining efficiency and machining accuracy of the workpiece 21 at that time. and the target retraction amount (P1 in the figure).

Next, the CPU 50 generates a ramp wave corresponding to these amounts (P3 in the figure) in the same manner as described above, and the D/A converter 55.5
6. Radial electromagnet 15 via magnetic bearing control device 47
．． By electrically controlling the magnetic force of 16, the target position in the radial direction of the rotary spindle 13 is set to A in the diagram A in FIG.
As shown in part 2, the rotary spindle 13 is momentarily changed in the forward and reverse directions to displace it (P4 in the same figure), and the above-mentioned overfeed and retraction cutting operations are performed (P5 in the same figure); In this way, as in the first embodiment, the machine of the grinding machine 10 can be improved by performing appropriate overfeed and retraction cutting operations by displacing the rotary spindle 13 in the rough grinding feed range or fine grinding feed range. It is possible to reliably improve the machining efficiency and machining accuracy of the workpiece 21, regardless of the mechanical error or the superiority or inferiority of responsiveness.

FIGS. 10 and 11 show a third embodiment of the present invention. This third embodiment uses an enloaf 521 position counter 48, etc., as in the first embodiment shown in FIG. The sizing device 45 as in the second embodiment is not used.

In this third embodiment, the CPU 50 rotates the motor 25 via the servo driver 27, moves the workpiece 21 in the radial direction, cuts the workpiece 21, and starts the grinding operation, and then controls the rotation of the motor 25 using the encoder 52. After the output signal from the encoder 52 is pulse-shaped and the direction is determined, the position counter 48 calculates the cutting position, and from this, the CPU 50 determines whether or not the current coarse grinding feed range has ended. Pl in Figure 10
), CP when it is determined that the current coarse grinding feed range has ended.
U50 is D/A converter 55.56° magnetic bearing control device 4
By electrically controlling the magnetic force of the radial electromagnets 15, 16 via the radial electromagnets 7, the radial target position of the rotary spindle 13 is gradually and continuously moved in the cutting direction as shown in line A in FIG. (P2 in the same figure) First, the rotating spindle 13 is gradually and continuously displaced in the radial direction.
Line B in Figure 1 is the motor 25. work table 22
B1 shows the rapid feed range, B2 shows the coarse grinding feed range, and B3 shows the fine grinding feed range, but as shown in the figure, B3 shows the main cutting position of the workpiece 21 at all and is horizontal. It becomes. Instead, as shown in diagram A in the same figure and as mentioned above, in order to gradually and continuously displace the rotary spindle 13 in the cutting direction in the fine polishing range after the rough polishing feed is finished, this rotary spindle 13 A fine grinding feed is performed by a displacement of only 13 (P3 in the same figure).

In this way, by adjusting the fine grinding feed range by displacing only the rotary spindle 13, it becomes possible to electrically adjust the V&
It is possible to reliably improve the machining efficiency and machining accuracy of the workpiece 21, regardless of the mechanical error of 0 or the quality of response.

In the above embodiments, the grinding method was explained for an internal grinder, but the present invention may also be used for an external grinder.

In addition, in the above embodiment, as shown in FIG. 12, the explanation was given mainly with the idea of displacing the rotating spindle 13 in parallel; however, as shown in FIGS. The grinding wheel may be tilted and displaced. This can provide the effect of correcting the inclination of the machining surface of the workpiece as the number of grindstones decreases.

In addition to the above embodiment, as shown in FIG. 14, the current value flowing through the radial electromagnets 15 and 16 of the magnetic bearing spindle is detected, and the target position of the rotating spindle is changed based on the detected current value. This is because the state of cutting, such as whether it is in the coarse grinding feed range or the fine grinding feed range, can be determined based on the above-mentioned current value.

Further, in the above embodiments, a grinder was described as a processing machine that implements the processing method, but the present invention may be practiced with other processing machines other than a grinder.

〔Effect of the invention〕

As explained above, according to the processing method of the present invention, since the tool performs the cutting operation of the workpiece by electrically controlling the magnetic force of the electromagnet of the magnetic bearing spindle, it is possible to electrically adjust the WI amount. At the same time, the responsiveness is dramatically improved, and it is possible to reliably improve the machining efficiency and machining accuracy of the workpiece, regardless of the mechanical error of the processing machine or the quality of the responsiveness.

[Brief explanation of the drawing]

1 to 6 are diagrams showing a first embodiment of the processing method according to the present invention, in which FIG. 1 is a perspective view of an internal grinder, FIG. 2 is a side sectional view of a magnetic bearing spindle, and FIG. Front sectional view, Figure 4 is a control block diagram of the internal grinder, Figure 5 is its flowchart, and Figure 6 is the relationship between the main cutting position of the workpiece and the overfeed and retraction cutting operations by the rotating spindle with respect to time. The cutting characteristic diagrams shown in FIGS. 7 to 9 are diagrams showing the second embodiment of the present invention,
Fig. 7 is a control block diagram of the internal grinding machine, Fig. 8 is a flow chart thereof, and Fig. 9 shows the relationship between the sizing signal corresponding to the machining dimensions of the workpiece and the overfeed and retraction cutting operations by the rotating spindle over time. Fig. 10 and Fig. 11 are diagrams showing the third embodiment of the present invention, Fig. 10 is a flowchart thereof, and Fig. 11 is a diagram showing the main cutting position of the workpiece and the displacement of the rotating spindle. Fig. 12, Fig. 13 (a) and (b) are a side view and Fig. 13 (a) and (b) respectively showing the attitude of the rotary spindle at the time of displacement in the above embodiment. FIG. 14 is a control block diagram showing another embodiment of the present invention. 10... Internal grinder 11... Magnetic bearing spindle 12... Main body 13... Rotating spindle 13a... Step parts 13b, 13c ... Small diameter portion 14 ... Grindstone table 15 (15a to 15d) ... Radial electromagnet 16 (
16a-16d)...Radial electromagnet 17.18...
...Rail 19...Bed frame 20...Chuck device 21...Work 22...Work table 23-25.28...・Motor 27...Servo driver 30...Flange part 31.32...Shaft/Axial electromagnet 34-36...
...Position sensor 38.39...Protection bearing 41...
・Whetstone 45...Sizing device 47...Magnetic bearing 1IilN control device 48...
...Position counter 50...CPU 51...ROM 52...Encoder 53...I10 boat 55-57...D/A Converter patent applicant Seiko Mki Co., Ltd. Agent Seiko Electronics Co., Ltd. 15c (1
6c) Front @ Front View 3 Diagrams Wholesale O. Noah Figure 4 Flowchart 5th Drawing Including h14 Tou Asa U Figure 6 Figure 1 Button Arro 77 Figure 7 Flowchart Figure 8 10 Figure 1 Katokome Nona f Imote A1 Figure 11 1゛゛1 side view of the rotating spindle! Figure 1712 Rotating spindle f flight 1st page Mouth diagram 13

Claims (5)

[Claims] (1) A rotating spindle with a tool provided at its end, an electromagnet that levitates this rotating spindle by magnetic force and supports the bearing, a position detecting means for detecting the radial position of the rotating spindle, and this position detecting means and a magnetic bearing control device that controls the magnetic force of the electromagnet to maintain the rotary spindle at a target position by inputting a signal from the rotary spindle. A machining method characterized by causing the tool to perform a cutting operation on a workpiece by changing. (2) The processing method according to claim 1, wherein the target position of the rotating spindle is changed based on the main cutting position of the processing machine. (3) The processing method according to claim 1, wherein the target position of the rotating spindle is changed based on a sizing signal from a workpiece size detection means. (4) The processing method according to claim 1, wherein the cutting operation by changing the target position of the rotating spindle is performed after the main cutting operation of the processing machine is stopped. (5) The processing method according to claim 1, wherein the target position of the rotating spindle is changed based on a current flowing through the electromagnet.