JPH01289652A - Work holding device of polishing machine - Google Patents

Abstract

PURPOSE:To prevent flaw on the polishing surface of a work by furnishing the work holder with a magnetic substance plate facing an electric magnet installed inside a drive shaft, and pulling up the work holder for a micro- distance by this electric magnet immediately before the processing is finished. CONSTITUTION:Before the rotation of a polishing plate 26 etc. is falling at the finishing time of processing to cause nullification of the dynamic pressure effect, current is supplied to an electric magnet (coil) 36 inside a drive shaft 31, and a work holder 40 is attracted to the drive shaft with the aid of a magnetic substance plate 46. This attraction lifts the work holder 40 for a micro- distance, and a work 22 grasped by the work holder 40 is moved apart from the polishing plate 26, which prevents flaws generated on the polishing surface of the work 22.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a polishing disk, and more particularly to an apparatus suitable for application to a polishing disk for polishing the core of a magnetic head or the like.

"Prior Art" FIG. 2 is an external view showing an example of this type of polishing machine. A rotating tank 2 is provided in the bed 1.

The rotating tank 2 is rotationally driven by a main shaft together with a polishing plate forming the bottom surface. A saddle unit 4 is slidably supported on a slide rail 3 fixed above the bed 1, and a work holder shaft 5 supported by the saddle unit 4 extends into the rotating tank 2.

A tool post 6 is slidably supported on the same slide rail 3. A machining fluid containing abrasive grains is supplied and circulated in the zero-rotation tank 2. Further, a rolling block 8 and a control box 9 are provided on the side.

FIG. 3 is a sectional view showing a conventional work holder shaft 5. As shown in FIG. The work holder shaft 5 consists of a sleeve 11 and a drive shaft 12 rotatably supported within the sleeve 11. The sleeve 11 is moved up and down by a feed motor (not shown) in the saddle unit 4, and the drive shaft 12 is moved up and down by a rotary motor (not shown). Rotationally driven.

A drive bottle 13 is fixed to the vicinity of the shaft end of the drive shaft 12 so as to protrude in the circumferential direction and pass through the drive shaft 12 . An annular vibration-absorbing rubber 14 is fitted near the shaft end.

Drive shaft 1 with drive bottle 13 and vibration absorbing rubber 14 attached
A work holder 15 is held at the shaft end of No. 2 by a cap nut 16.

As shown in FIG. 4, the work holder 15 has a substantially disk shape, and is provided with a hole 17 opening upward and engagement grooves 18 and 19 in the center. Further, a screw 20 is formed on the outer periphery of the upper small diameter portion of the work holder. Work holder 15
With the shaft end of the drive shaft 12 inserted into the hole 17 and the drive pin 13 inserted into the engagement grooves 18 and 19, the cap nut 16 is screwed onto the screw 20 and held on the drive shaft 12. be done. The work holder 15 is restrained in the rotational direction by engagement between the engagement fR18, 19 and the drive bin 13, and in the axial direction, there is a position where the shaft end of the drive shaft 12 contacts the bottom of the hole 17, and a position where the drive bin 13 is in contact with the bottom surface of the hole 17. It is movable between the cap nut 16 and the cap nut 16.

A disk-shaped work plate 2 is provided on the lower surface of the work holder 15.
A plurality of workpieces 22, such as magnetic held cores, are bonded with wax to the lower surface of the work plate 21.

A polishing plate 26 is provided inside the rotating tank 2 which is rotationally driven by a main shaft 25 . Fine grooves with a depth of 0.01 to 0.02 m5+ are uniformly formed on the surface of the polishing plate I.26. This minute groove was machined using the tool rest 6.

When polishing the workpiece 22, the sleeve 1] is lowered to a position where the workpiece 22 can come into contact with the polishing plate 26, and the drive @12 is rotated to rotate the workholder 15.

On the other hand, the main shaft 25 is also rotationally driven to rotate the polishing plate 26. Then, a machining fluid 27 containing abrasive grains is supplied to the center of the rotating tank 2.

The machining fluid 27 flows to the peripheral edge of the rotating tank 2 due to centrifugal force and is collected. At this time, due to the dynamic pressure effect of the machining fluid 27, the workpiece 22 is pushed against the polishing plate 2 against the weight of the work holder 15.
It is rotated in a floating state from 6 to 6. Processed product 2
The machining liquid 2 passing through the gap between 2 and the polishing plate 26
7, the processed ¥1522 is precisely polished without distortion.

"Problems to be Solved by the Invention" The conventional apparatus described above has a problem in that minute scratches and streaks may be formed on the polished surface of the workpiece 22. This is because when the rotation of the drive shaft 12 and the polishing plate 26 stops at the end of machining, the dynamic pressure effect generated by the machining fluid 27 between the workpiece 22 and the polishing plate 26 disappears, and the floating workpiece 22 lands on the polishing plate 261.

At this time, it is considered that the workpiece 22 is damaged.

In order to prevent the machining Th22 from landing on the polishing plate 26 after the machining is completed, it is conceivable to gradually raise the sleeve 11 while rotating the polishing plate 26 and release the work holder 15 upward. axis 1
The work holder 15 is tilted when the workpiece 2 is raised or the drive bin 13 comes into contact with the cap nut 16, and the workpiece 22 may be broken, which cannot be adopted.

The present invention has been made to solve the above problems, and its purpose is to provide a workpiece holding device that does not cause minute scratches on the polished surface of the workpiece. .

"Means for Solving the Problem" In order to achieve the above object, the present invention provides an engaging protrusion provided near the @ end of the drive shaft, and is engaged with the engaging protrusion to be restrained in the rotational direction. and a work holder held at the shaft end of the drive shaft so as to be freely movable in the axial direction, and a workpiece held on the lower surface of the work holder can come into contact with a rotationally driven polishing plate. In the workpiece holding device,
There is provided a workpiece holding device for a polishing disk, characterized in that an electromagnet is provided in the drive shaft, and a magnetic plate facing the electromagnet is provided in the work holder.

"Operation" In the workpiece holding device configured as described above, when the electromagnet is energized, the shaft end surface of the drive shaft is magnetized and attracts the workholder. Therefore, at the end of machining, before the rotation of the polishing plate etc. drops and the dynamic pressure effect disappears, the electromagnet is energized and the work holder is attracted to the drive shaft, thereby preventing the polishing surface of the workpiece from coming into contact with the polishing plate. be able to.

In addition, the distance that the work holder moves when attracted by the electromagnet is extremely random, and after being attracted, the work holder becomes integrated with the drive shaft and does not move loosely, so the work holder may tilt and break the workpiece. There is nothing to do.

"Example" Embodiments of the present invention will be described with reference to the drawings.

The general outline of the polishing machine to which the embodiment is applied is the same as that shown in FIG. 2, so the explanation will be omitted.

FIG. 1 is a longitudinal sectional view showing the workpiece holding device.

The drive shaft 31, which forms part of the work holder shaft 5, can move up and down and rotate as in the conventional device. Drive shaft 3
A drive pin 32, which is an engaging protrusion, is installed protruding in the circumferential direction near the shaft end of the shaft 1, and an annular vibration absorbing rubber 33 made of urethane rubber is fitted therein.

The drive shaft 31 is different from conventional devices and is made of a stainless steel member. A shaft end disk 34 made of a magnetic material is fitted onto the end of the drive shaft 31 to form a shaft end surface of the drive shaft 31 .

A shaft-shaped iron core 35 is provided inside the cylindrical drive@31 in close contact with the disk 34, and a coil 36 is wound around the iron core 35 to constitute an electromagnet. Shaft end disc 34
constitute the magnetic poles of the electromagnet.

A lead wire 37 from the coil 36 is drawn out to the outside via a slip ring (not shown), and is connected to a power source 39 via a switch means 38 such as a relay or a transistor.
It is possible to cut off the current supply to the coil 36.

Drive shaft 3 to which drive bin 32 and vibration absorbing rubber 33 are attached
A work holder 40 is held at the end of the shaft by a cap nut 41. The shaft end of the drive shaft 31 is connected to the work holder 4
0, and the drive pin 32 is inserted into the engagement groove 43.4.
4, the cap nut 41 is screwed onto the screw 45, which is the same as in the conventional device.6 In the device of this embodiment, the work holder 40 main body and the cap nut 41 are made of stainless steel. There is. Then, hole 4 of the work holder 4°
A bottom wall disc 46 made of a magnetic material is embedded and fixed in the bottom wall of the drive shaft 2, that is, in the portion facing the shaft end of the drive shaft 31.

The work holder 40 has a bottom wall disk 4 fixed to the bottom of the hole 42.
The cap nut 41 is movable in the axial direction between a position where the cap nut 41 abuts the shaft end disk 34 of the drive shaft 31 and a position where the cap nut 41 abuts the drive bottle 32.

A disk-shaped work plate 2 is provided on the lower surface of the work holder 40.
] is adhered, a plurality of processed \@22 are bonded with wax to the lower surface of the work plate 21, and polishing is performed between the work plate 21 and the polishing plate 26, as in the conventional apparatus.

The operation of the workpiece holding device configured as above will be explained.

When performing polishing, first, the drive shaft 31 is lowered to bring the workpiece 22 into contact with the polishing plate 26. At this time,
The vertical position of the drive shaft 31 is determined so that the gap between the shaft end disk 34 of the drive shaft 31 and the bottom wall disk 46 is approximately several inches. Then, the machining fluid 27 is supplied to the rotary tank 2, and the drive shaft 3
1 and the work holder 40, and the polishing plate 26
The float polishing process is performed by rotating the work holder 40. The float amount of the work holder 40 at this time is a small amount.

Near the end of machining, when the rotational speed of the spindle 25 and the polishing plate 26 has dropped to 1 to several rpm, the coil 36 is energized, and the bottom wall disc 46 is attracted by the attraction force of the electromagnet, and the work holder 40 is It is attracted to the shaft end disc 34 of the drive shaft 31. Then, pull up the drive shaft 31 that has stopped rotating, and tighten the cap nut 4.
1, the work holder 40 is removed from the drive shaft 31, and the workpiece 22 is replaced.

In this way, the work holder 40 is raised by a minute distance just before the polishing plate 26 (main shaft 25) stops rotating and the dynamic pressure effect of the machining fluid 27 decreases, thereby preventing the workpiece 22 from landing. There is no risk of scratches on the polished surface of the processed workpiece 22.

"Effects of the Invention" As explained above, the present invention has the above-mentioned structure and has a structure in which the work holder is attracted to the drive shaft using an electromagnet and pulled up by a small distance. This has the excellent effect of being able to raise the holder by a small distance without inclining it, and allowing a workpiece subjected to float polishing to be removed without landing on the polishing plate. Therefore, there is an effect that there is no risk of scratches on the polished surface of the workpiece.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view showing a polishing machine to which the device of the present invention is applied, FIG. 3 is a sectional view showing a conventional device, and FIG. FIG. 4 is a sectional view taken along line A-A in FIG. 3; 2190 rotating tank, 51. , work holder axis, 22
゜8, Workpiece, 25, Main shaft, 26, Polishing plate, 31, Drive shaft, 32. ,, drive bottle engaging protrusion), 34,, shaft end disk, 35.
,,iron core, 36 ,,coil, 40. ,, Work holder, 41°91 bag nuts, 43,44.
,,engaging groove, 46,,. Bottom wall disc. Figure 2

Claims (1)

[Claims] An engaging protrusion provided near the shaft end of the drive shaft, and a work holder that engages with the engaging protrusion and is held at the shaft end of the drive shaft so as to be restrained in the rotational direction but movable in the axial direction. Prepare,
In a workpiece holding device for a polishing machine in which a workpiece held on the lower surface of the workholder can come into contact with a rotationally driven polishing plate, an electromagnet is provided in the drive shaft, and an electromagnet is provided on the workholder so as to face the electromagnet. A workpiece holding device for a polishing machine, characterized in that it is provided with a magnetic plate.