JP2001150341A - Work holding device in polishing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve polishing accuracy by eliminating a vibration phenomenon of a work as well as to improve follow-up rotational performance of the work. SOLUTION: The work holding device in a polishing machine is constituted by rotatably supporting a rotational member 2 for holding a work 1 on a support link 3 by a radial bearing 8 at the outer periphery of the rotational member 2, and supporting it on a line (a rotational axis of the work) passing the rotational center of the rotational member 2 by a pivot bearing 7 composed of a pivot 5 integrated with the rotational member 2 and a receiving part 6 provided on the support link 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding device for a polishing machine, and more particularly, to a link type in which a rotating shaft of a work in polishing an optical element or the like is supported on an upper shaft of the polishing machine via two orthogonal axes. A work holding device.

[0002]

2. Description of the Related Art As a work holding device of this type, the present applicant has previously proposed a device in which the outer periphery of a rotating member that holds and rotates a work is rotatably supported by a support link.

That is, as shown in FIG. 6, a link-type work holding device in this polishing machine has two support links 113 at the lower end of a stay 21 fixed to a polishing machine upper shaft 27.
A link mechanism 120 composed of a lens 114 and a line passing through the rotation center of the holding cylinder (rotating member) 112 of the sticking tray 19 to which the lens to be processed (work) 11 is stuck and the rotation center of the polishing plate 10 (rotation axis of the work) The holding cylinder 112 is rotatably supported by a support link 113 by a bearing bearing 118 provided on the outer periphery, and is swingably provided via two axes a and b orthogonal to c.

[0004]

However, in the above-described work holding device, both the thrust load and the radial load are received only by the bearings 118.
Rotational friction is generated in the bearing 118, and in particular, when processing a small-diameter lens or a lens having a large radius of curvature requiring rotation of the holding cylinder 112, the subordinate rotation during polishing is deteriorated. The processing accuracy is deteriorated due to generation of astigmatism.

[0005] Further, the rigidity of the holding cylinder 112 is impaired due to the progress of wear in the bearing 118 due to the thrust load. This is a reason why the lens 11 to be processed is not stably held during the polishing process, and causes vibration, which adversely affects the processing accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and has as its object to improve the subordinate rotation of a work and to improve the polishing accuracy by eliminating the vibration phenomenon of the work.

[0007]

According to the first aspect of the present invention, which achieves the above object, the rotating shaft of a workpiece in polishing an optical element or the like is supported on an upper shaft of a polishing machine via two orthogonal axes. In the link type holding device, a pivot bearing for holding a work and rotating the work in a thrust direction on a rotation axis of the rotation member, and a radial bearing on an outer periphery of the rotation member. It is characterized in that it is configured to be rotatably supported on a support link by a radial bearing.

According to the first aspect of the present invention having the above structure, a thrust load is applied to the pivot bearing, and only a radial load is applied to the radial bearing. Therefore, rotational friction in the radial bearing is reduced, and polishing is performed. Since the inside rotation is not impaired, and at the same time, the wear in the radial bearing is reduced, the rigidity of the rotating member is maintained.

In particular, the invention of claim 3 of the present invention can further improve the rotation of the work according to the invention of claim 2, and the invention of claim 4 further improves the rotation of the work. However, highly accurate polishing of the micro-diameter lens can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a work holding device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 illustrates the basic structure of the present invention. In this work holding apparatus, a rotating member 2 for holding a work 1 is provided on a support link 3 by a radial bearing 8 on the outer periphery of the rotating member 2. And a pivot 5 integrally formed with the rotating member 2 and a receiving portion 6 provided on the support link 3 on a line (rotation axis of the work) c passing through the center of rotation of the rotating member 2. It is supported by a bearing 7.

For this reason, a thrust load is applied to the pivot bearing 7 and only a radial load is applied to the radial bearing 8, so that rotational friction in the radial bearing 8 is reduced.
Rotation during polishing is not impaired, and at the same time wear in the radial bearing 8 is reduced, so that the rigidity of the rotating member 2 is maintained.

(Embodiment 1) FIG. 2 is a sectional front view of a main part of a work holding device in a polishing machine according to Embodiment 1 of the present invention, and FIG. 3 is an exploded perspective view of a link mechanism. .

In the drawing, the stay 21 is fixed to the lower end of the upper shaft 27 of the polishing machine by the bolt 22, and the link mechanism 20 is connected to the stay 21. Link mechanism 2
0 is a pair of support links 13 and 14 as shown in FIG.
The two support links 13 and 14 are orthogonal to each other, and the two open ends 13a and 14a and 13b and
4b are rotatably connected to each other by a pivot 23.

One of the support links 14 is formed in a U-shape, and a central portion equidistant from both open ends 14a and 14b is rotatably connected to a lower end of the stay 21 by a pivot 24.

The other support link 13 is formed in a substantially U-shape, and a holding portion 13c is formed in an intermediate portion equidistant from both open ends 13a and 13b, and is formed in a convex shape upward. .

At the lower end of the inner wall of the holding portion 13c, a bearing bearing 18 as a radial bearing 8 (see FIG. 1) is fixed by a retaining member 25, and a cylindrical holding cylinder is provided via the bearing bearing 18. 12 is rotatably held. The holding cylinder 12 is fitted to the bearing 18 from below with the Sekiguchi end facing downward.

A conical portion 15 is integrally provided at the center of the upper end of the holding cylinder 12.
However, it is in contact with the receiving portion 16 having a plurality of balls, which is fixed to the center of the upper end of the inner wall of the holding portion 13c, via the balls.

The receiving portion 1 having the conical portion 15 and the ball
6, a pivot ball bearing 17 is formed. In this state, the holding cylinder 12 is locked at the upper end of the bearing bearing 18 by an E-shaped stop ring 26 fitted to the outer periphery and is rotatably held. .

The line c passing through the center of rotation of the holding cylinder 12 and the center of rotation of the polishing plate 10 below the link mechanism 20 is a line a passing through the center of the pivot 23 and a pivot 24 perpendicular to this.
At the intersection with the line b passing through the center of the line.

The lens attaching surface 1 at the center of the lower end of the attaching plate 19
A lens 11 to be processed is attached to 9a at a pitch or the like.

The outer diameter of the cylindrical portion 19b at the upper end of the sticking tray 19 is dimensioned to fit tightly and smoothly into the inner diameter of the opening of the holding cylinder 12 without causing backlash. The sticking tray 19 fitted therein has its flange portion 19c abutted on the opening edge of the holding cylinder 12 located at the lower end of the bearing 18 so that it can rotate together with the holding cylinder 12.

As described above, in the polishing process, after the sticking plate 19 integrally having the lens 11 to be processed is fitted and held inside the holding cylinder 12, the lens 11 to be processed is
When the polishing plate 10 is pressed upward, the rotation of the polishing plate 10 and the swinging motion of the polishing machine upper shaft 27 or the polishing plate 10 are started.
At this time, a thrust force and a bearing force simultaneously act on the holding cylinder 12 via the lens 11 to be processed. And
The thrust force acts on the pivot ball bearing 17, and therefore,
Bearing Only radial force acts on the bearing 18 and no thrust force acts.

Therefore, the frictional force generated in the bearing 18 is extremely small as compared with the case where the thrust force is simultaneously applied. For example, when the bearing 18 is a rolling bearing, the ball is in sliding contact when a combined force is applied, whereas it is in a pure rolling contact when a pure radial force is applied.

At the same time, since the load on the bearing shaft 18 is reduced, wear is suppressed, and the pivot ball bearing 17 itself does not rattle even if worn, so that the rigidity of the holding cylinder 12 is maintained. Dripping.

With the above operation, when a lens having a small diameter or a lens having a large radius of curvature is used as the lens 11 to be processed, the astigmatism of the Newton ring, which tends to occur up to now, due to the poor subordinate rotation. The aberration and the vibration during the processing are eliminated, and the processing accuracy is remarkably improved.

(Embodiment 2) FIG. 4 is a sectional view of a main part of a work holding apparatus according to Embodiment 2 of the present invention. This embodiment differs from the work holding device shown in FIGS. 2 and 3 in that a jewel bearing 37 is used instead of the pivot ball bearing 17.

The jewel bearing 37 has a concave spherical surface as a bearing surface and is made of a high hardness material such as sapphire, and a jewel receiver 36, and instead of the conical portion 15, at the center of the upper end of the holding cylinder 32, The pivot 35 has a convex spherical portion having a smaller radius of curvature than the jewel receiver 36 at the tip. If the radius of curvature of the convex spherical portion at the tip of the pivot 35 is small, the rotational friction at this bearing portion is very small, so that the holding cylinder 12 and the holding cylinder 12 are further compared with the first embodiment shown in FIG. The rotation property of the lens 11 to be processed, that is, the rotation property of the work is improved.

Therefore, even if the lens 11 to be processed is a small-diameter lens having a lens diameter of, for example, 3 mm or less, high-precision polishing becomes possible.

(Embodiment 3) FIG. 5 is a sectional view of a main part of a work holding device according to Embodiment 3 of the present invention. In this embodiment, a hydrostatic bearing 48 is used as the radial bearing 8 (see FIG. 1) instead of the pairing bearing 18.

The opening 13d of the central portion the lower end of the holding portion 13c _o of the support link 13A is formed in a cylindrical shape, the cylindrical internal diameter is slightly larger than the outer diameter of the holding tube 42, Thus, the holding cylinder 42 Is airtightly fitted into the opening 13d,
And it is freely rotatable.

A plurality of groove-shaped pockets 49 are provided on the inner wall of the opening 13d facing the outer periphery 42a of the holding cylinder 42 symmetrically with respect to the center line c which is the rotation axis of the work. The pocket 49 communicates with an air hole 50 formed in the support link 13A and a pipe 51 connected to the air hole 50 so that air at a constant pressure is sent into the pipe 51 by an air supply device (not shown). Has become.

Therefore, in this hydrostatic bearing 48,
Due to the air pressure sent to the pocket 49, the holding cylinder 42 floats, and there is almost no rotational friction.

Further, since the holding cylinder 42 does not use the E-shaped stop ring 26, the pivot 45 and the receiving portion 46 at the upper end of the holding cylinder 42 prevent the holding cylinder 42 from dropping by its own weight. the space 52 around the pivot bearing 47 made of a holding portion 13c _o the support link 13A
Are formed to communicate with each other.
Is connected to an intake device (not shown) by a pipe 54.

Therefore, the holding cylinder 42 is held in the opening 13d by sucking the air in the space 52 by the suction device. By controlling the intake pressure, the thrust load received by the pivot bearing 47 can be adjusted.

According to this embodiment, since the rotational friction generated in the radial bearing composed of the hydrostatic bearing 48 is extremely small, the first embodiment shown in FIGS.
When the number is two or more, the rotation property of the work is improved, and the highly precise polishing of the micro-diameter lens becomes possible.

[0037]

As described above, according to the present invention,
Since the thrust load is received by the pivot bearing and only the radial load is received by the radial bearing, rotation is improved by reducing the rotational friction of the rotating shaft of the work, and rigidity of the work rotating shaft is reduced by reducing the wear of the radial bearing. Thereby, the subordinate rotation property of the work and the vibration phenomenon of the work are suppressed, and the polishing accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a work holding device showing a basic configuration of the present invention.

FIG. 2 is a cross-sectional view of a main part of the work holding device according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view of a link mechanism of the work holding device shown in FIG. 2;

FIG. 4 is a cross-sectional view of a main part of a work holding device according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a work holding device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a work holding device previously proposed by the present applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work 2 Rotating member 3,13,13A Support link 7,47 Pivot bearing 8 Radial bearing 10 Polishing dish 11 Worked lens (work) 12,32,42 Holding cylinder (rotating member) 17 Pivot ball bearing (Pivot bearing) ) 18 Bearing bearing (radial bearing) 19 Affixing plate 37 Jewel bearing (pivot bearing) 48 Static pressure bearing (radial bearing)

Claims (4)

[Claims] In a link type holding device in which a rotation axis of a work in polishing an optical element or the like is supported on an upper shaft of a polishing machine via two orthogonal axes, a rotation for holding the work and rotating the work. A polishing machine configured to rotatably support a member on a support link by a pivot bearing that bears in the thrust direction on the rotation axis of the rotating member and a radial bearing that bears the outer periphery of the rotating member in the radial direction. Work holding device. 2. The apparatus according to claim 1, wherein said pivot bearing comprises a pivot ball bearing. 3. The work holding device according to claim 1, wherein the pivot bearing is a jewel bearing. 4. The work holding device in a polishing machine according to claim 1, wherein said radial bearing comprises a hydrostatic bearing formed by forcing a pressure fluid into a gap between an outer periphery of said rotary member and said support link. .