JPS60177833A - Vacuum chuck device - Google Patents

Abstract

PURPOSE:To facilitate mount/dismount of work thus to improve the machining efficiency in a vacuum chucking device for adsorbing and holding a thin board by supporting a work holder floatably against the rotary drive shaft and enabling usage of vacuum chuck. CONSTITUTION:Upon lifting of ram 9 in a vacuum chucking device, the vacuum chucking body 14 will move relatively with the drive shaft 20 and lower and the holding body 15 will contact against a drive pin 16 to be suspended. Under this state, work W is adsorbed to the vacuum adsorbing face 17 of vacuum chucking body 14 to lower the ram 9 while the spindle 11 is rotated to rotate the vacuum chucking body 14 constituting a work holder 10 through a drive shaft 20, drive pin 21 and an engaging groove 22. Lowering of ram 9 will stop after contacting of work W against the lapping machine 3 and lowering by predetermined distance. Consequently, suspension of holding body 15 is released to contact the work W against the lapping machine 3 and perform machining. Here, the magnetic field 28 will move axially together with a magnet 29 to seal the gap 27 continuously thus to maintain the vacuum chamber 26 air-tight.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vacuum chuck device that holds a workpiece by vacuum suction.

<Prior art> The surface of a thin plate workpiece is rotated two-to-two against a lapping surface plate immersed in a polishing solution, and the workpiece is held in an ultra-precision boring machine that finishes the workpiece into an ultra-precision mirror surface. The work piece to be attached to the bottom surface of the holder is attached with adhesive. Therefore, it was extremely troublesome to attach and detach the workpiece, resulting in poor processing efficiency.

It is very efficient to hold such a thin workpiece with a vacuum chuck, but in the ultra-precision boring machine mentioned above, it is necessary to bring the surface of the held workpiece into proper contact with the surface of the lapping surface plate. Therefore, the work holder must be connected to the rotational drive shaft so that it can float. Therefore, a gap is formed at the fitting part between the work holder and the rotation drive shaft to allow the work holder to 70-ch, so when the vacuum chuck is used, the gap communicates with the atmosphere. Therefore, it is difficult to secure vacuum properties, and the vacuum suction holding power of the workpiece decreases, and external force is applied to the vacuum chuck due to the rubber hose that connects the vacuum chuck and the vacuum source, making it difficult to handle workpieces that require ultra-precision. Vacuum chucks were not used because of problems that affected machining accuracy.

<Object of the Invention> The object of the present invention is to solve the above-mentioned problem Z and make it possible to use a vacuum chuck that allows easy attachment and detachment of a workpiece as a workholder supported in a floating manner on a rotary drive shaft. It is.

<Configuration of the Invention> The characteristic configuration of the present invention is that the vacuum chuck body provided with the vacuum suction surface 7 is allowed to float with respect to the rotational drive shaft;
The rotary drive shaft is provided with seven negative pressure passages that communicate with the vacuum suction surface and the vacuum source, and a magnetic fluid is provided in the fitting gap between the vacuum chuck body and the rotary drive shaft. At the same time, a magnet is attached to the vacuum chuck body or the rotary drive shaft at the part where the magnetic fluid is sealed, and a magnetic fluid seal 7 is applied to the fitting gap.

<Example> Embodiments of the present invention will be described below based on the drawings.

Fig. 1 shows the main configuration 2 of an ultra-precision boring machine using the device of the present invention, 1 is a fixed base, and on this fixed base 1 there is a turntable 2Z that rotates around the rotation center 0. 2 has a lamp base 3 which rotates integrally with the same rotation center 0. Reference numeral 4 denotes a spindle head, which is provided integrally with the slide base 5 that feeds and moves along the support rail 20 guide surface 8 of the support stand 6 installed on the fixed base 1 in a direction parallel to the lap surface plate 30 surface. There is. The main spindle head 4 has a ram 9 that moves up and down in the direction of a vertical axis perpendicular to the surface of the lap surface plate 30, and a main shaft 11 (Fig. 2) is rotatable around the vertical axis through the ram 9. A work holder 10 is connected to the lower end of the main shaft 11 so as to be relatively slidable and floating in the vertical direction. 12 is a drive motor for rotating the main shaft, 13
is the drive motor for vertically feeding the ram. W is a thin plate-shaped work held on the lower surface of the work holder 10. The work holder 10 is brought into contact with the surface of the WY lap platen 3 held on the lower surface thereof, and is polished to an ultra-precise mirror surface by rotating the work holder 100 times and rotating the lap platen 3 by the turntable 2.

Therefore, the present invention provides the above-mentioned work holder IOY vacuum chuck. Its specific configuration will be explained with reference to FIG.

14 is a vacuum chuck main body. This vacuum chuck main body 14 has a vacuum chamber 16, and this vacuum chamber 16 and a communication path 1
The vacuum suction surface 17Y for the workpiece W is provided with a large number of annular suction grooves 19 communicating through eight holes.

15 is a holder integral with the vacuum chuck body 14.

The upper end of a drive shaft force is integrally connected to the lower end of the main shaft 11 on the same axis, and the vacuum chuck main body 14 allows axial movement and 70 degrees of movement in response to this drive force force. They are connected in rotational direction. That is, the vacuum chuck main body 14 is provided with an engagement groove n on two sides long in the axial direction of the drive shaft, and the lower end of the drive shaft is provided with a drive pin 21 that engages with the engagement groove n. The hole in the holder 15 that fits around the outer periphery of the drive shaft has a gap of 27ya to allow floating of the vacuum chuck body 14.
The diameter is 1" and allows for a loose fit.

Further, a negative pressure passage n communicating with the vacuum chamber 16 included in the vacuum chuck body 14 is provided in the drive shaft 20, and a negative pressure passage n is provided in the drive shaft 20.
Connected to a vacuum source. The connection structure between the negative pressure passage device and the vacuum source is such that a distributor 25 is fixed to the lower end of the ram 9, a connecting pipe 24Y is connected to the distributor b to connect to the vacuum source, and the negative pressure passage 23 is connected to the distributor 25 via the distributor 25. It is a connected structure. The seal is a sealing material that seals the relative rotating surface Z between the distributor 5 and the main shaft 11.

The vacuum chuck body 1 is loosely fitted to the drive shaft as described above.
The gap valley between the hole of the holding body 15 in No. 4 and the drive shaft addition is the vacuum chamber 16.
7. A seal must be applied to prevent communication with the atmosphere. Furthermore, a special seal is required to allow the vacuum chuck body 14 to move and float in the axial direction with respect to the drive axis force. Therefore, in the present invention, a magnetic fluid is applied to the gap n to satisfy the above requirement. That is, a magnetic fluid 28, which is a solution in which ferromagnetic fine particles are stably dispersed in a liquid phase, is sealed in the gap n, and a ring-shaped magnet 29 is attached to the holder 15 at the sealed part of the magnetic fluid part.
It has one seal structure. The connection structure between the vacuum chuck main body 14 and the drive shaft is reversed to that described above, with a protruding shaft provided on the vacuum chuck main body 14 side, and a hole provided in the drive shaft into which the protruding shaft fits loosely with a gap. and engage with a dry pin.
A magnetic fluid sheet A/comprised of the magnetic fluid 3 and magnet 4 may be provided in the loose fitting gap.

Since the present invention has the above-described structure, the vacuum chuck body 1 is positioned above the lap surface plate 3 due to the rise of the ram 9.
4 moves relative to the drive shaft due to its gravity and falls by ℃,
The holding body 15 is in a suspended state by hitting the drive pin 16.

In this state, the workpiece is held by suction on the vacuum suction surface 17 of the WY vacuum chuck main body 14, and as the ram 9 moves downward, the main shaft 11 rotates about the drive shaft, and the workpiece is attached to the workpiece holder via the drive pin 21 and the engagement groove 22. The vacuum chuck main body 14 comprising a 10-vib is rotated. The downward movement of the ram 9 stops at a position where the workpiece W has further descended by a certain amount after contacting the lap surface plate 3. Therefore, as the ram 9 descends by a certain amount, the workpiece W comes into contact with the lap surface plate 3, and the vacuum chuck body 14, which restricts the downward movement, moves relative to the drive shaft, and the drive pin 21 slides in the engagement groove 22. The suspension of the moving holder 15 is released, and the workpiece W is brought into contact with the lapping surface plate 3 under the gravity of the vacuum chuck 1 main body 14 itself, and the boring process is performed. After processing of the workpiece W is completed, when the ram 9 is raised by a certain amount, the drive pin 21 engages with the holder 15,
Thereafter, the vacuum chuck main body 14 is lifted together and separated from the workpiece W flat plate 3, and the negative pressure is cut off to remove the workpiece from the vacuum suction surface 17 of the workpiece WY vacuum chuck main body 14.

Here, when the vacuum chuck main body 14 and the drive shaft rotate relative to each other in the axial direction due to the vertical movement of the ram 9, the magnetic fluid array sealed in the gap between the holder 15 and the drive shaft rotates as described above. Since the magnet 4 also moves with the relative movement in the axial direction, the magnet 4 follows suit, and the gap 27 is always sealed, the vacuum chamber 26 is kept airtight, and the vacuum suction force of the vacuum suction surface 17 is ensured.

<Other Examples> Negative pressure passage % provided around the drive shaft and vacuum chuck 1
As shown in FIG. 3, a passage 30 is provided in the holder 15 and the vacuum chuck body 14, and the negative pressure is passed through the distributor 31 integrally provided in the holder 15. A holder 1 is formed in the upper and lower parts at the center of the distributor 31Y and communicates with the passageway.
There is a magnetic fluid in the gap Mα between 5 and the drive shaft, 27h, 28
It is possible to change the design to a structure in which an annular magnet 4α, 29jSY is placed on the holder 15 side of the sealed part (8) in this magnetic fluid 28, and with this structure, due to the difference between vacuum and atmospheric pressure The force with which the vacuum chuck body 14 floats is reduced, and the machining accuracy of the workpiece W is further improved.

<Effects of the Invention> As described above, according to the present invention, the vacuum chuck main body Y is supported while ensuring vacuum properties and allowing floating relative to the drive shaft, making it possible to use the vacuum chuck as a work holder. Therefore, by controlling the degree of vacuum, it becomes very easy to attach and detach the workpiece, improving processing efficiency.In addition, since the rubber hose etc. for guiding the vacuum is not connected to the Z vacuum chuck body, the elasticity of the rubber hose etc. This has the special advantage that no external force is applied to the vacuum chuck body and does not adversely affect the machining accuracy of the workpiece.

[Brief explanation of the drawing]

Fig. 1 is a side view of the essential parts of an ultra-precision boring machine to which the present invention is applied, Fig. 2 is a sectional view of the essential parts of the inventive machine, and Fig. 3 is a sectional view of the essential parts of the present invention.
The figure is a sectional view of a main part showing another embodiment Z of the device of the present invention. 4-pindle head, 9@e-ram, 1o-fist, work holder, 11@-main shaft, 1411-vacuum chuck body, 15-holding body, 17--vacuum suction surface, machining・
・Drive shaft, 21... Drive pin, n... Engagement groove,
Field...Negative pressure passage, Sae...Connection pipe, 6...Distributor, A...Seal, n...E gap, fat, row α
, 28b...Magnetic fluid, 4, 291Z, 29A...
Magnet, J... passage, 31... distributor. Figure 1 Figure 2

Claims (1)

[Claims] A vacuum chuck main body having a vacuum suction surface is allowed to float relative to a rotational drive shaft, and is connected to the rotational direction by engagement, and a vacuum chuck body is provided within the rotational drive shaft that communicates the vacuum suction surface with a vacuum source. A pressure passage is provided, a magnetic fluid is sealed in the fitting gap between the vacuum chuck body and the rotational drive shaft, and a magnet is arranged on the vacuum chuck body or the rotational drive shaft at the part where the magnetic fluid is sealed, and the fitting A vacuum chuck device featuring a magnetic fluid seal in the gap.