Information
-
Patent Grant
-
6830505
-
Patent Number
6,830,505
-
Date Filed
Monday, August 25, 200321 years ago
-
Date Issued
Tuesday, December 14, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 451 262
- 451 259
- 451 269
- 451 270
- 451 271
- 451 272
- 451 261
- 451 264
-
International Classifications
-
Abstract
The polishing machine is capable of evenly applying a pressing force from an upper polishing plate to work pieces accommodated in through-holes of carriers. The polishing machine comprises: a plurality of the carriers provided around a center of gravity of an upper polishing plate and sandwiched between the polishing plates. Circular motion of the carriers, without revolving, are performed independently. Centers of gravity of the work pieces, which are held by the carriers, are simultaneously moved close to a center of gravity of the upper polishing plate and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces are equal.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a polishing machine, more precisely relates to a polishing machine capable of polishing both sides (faces) of work pieces, e.g., silicon wafers, by an upper polishing plate and a lower polishing plate.
A conventional polishing machine for polishing both sides of work pieces, e.g., silicon wafers, is shown in FIG.
16
. In
FIG. 16
, a lower polishing plate
200
and an upper polishing plate
202
are rotated in predetermined directions. Carriers
208
, which are driven by an internal gear
204
and a sun gear
206
, are provided between the polishing plates
200
and
202
. Through-holes (not shown), in each of which a work piece to be polished is held, are bored in the carriers
208
. Both sides (faces) of the work pieces held in the through-holes are simultaneously polished by the polishing plates
200
and
202
.
The lower polishing plate
200
is mounted on a lower board
209
and rotated together with the lower board
209
. The lower board
209
is rotatably mounted on a base
210
with a bearing
212
. Torque of an electric motor
214
, which rotates the lower board
209
, is transmitted to the lower board
209
by transmission gears
216
and a cylindrical shaft
217
.
The upper polishing plate
202
is rotated by torque of an electric motor
224
, which is transmitted by transmission gears
218
and a shaft
219
. The internal gear
204
is rotated by torque of an electric motor
226
by transmission gears
220
and a cylindrical shaft
221
. Further, the sun gear
206
is rotated by torque of an electric motor
228
by transmission gears
222
and a shaft
223
.
As shown in
FIG. 17
, a plurality of carriers
208
are mounted on the lower polishing plate
200
, and a plurality of the through-holes
230
, in which the work pieces will be accommodated and held, are bored in each carrier
208
.
Gear teeth for engaging with the internal gear
204
and the sun gear
206
are formed on an outer edge of each carrier
208
. By rotating the internal gear
204
and the sun gear
206
, the carriers
208
are revolved and orbited around the sun gear
206
by difference of rotational speeds of the two gears
204
and
206
.
The carriers
208
, in each of which the work pieces are held in the through-holes
230
, are sandwiched between the polishing plates
200
and
202
, then the polishing plates
200
and
202
, the internal gear
204
and the sun gear
206
are respectively rotated at predetermined rotational speeds. The work pieces are revolved and orbited around the sun gear
206
together with the carriers
208
, so that the both sides of the work pieces can be polished simultaneously.
However, in the polishing machine shown in
FIGS. 16 and 17
, each of the carriers
208
is revolved on its own axis, so a peripheral speed of an inner part of the carrier
208
is different from that of an outer part. Further, the work piece held in the through-hole
230
of the carrier
208
is also revolved, so a peripheral speed of an inner part of the work piece is different from that of an outer part.
By the difference of the peripheral speeds of the carrier
208
, the work pieces held in the inner part and the outer part of the carrier
208
cannot be polished uniformly, and abrasion spots are sometimes formed in the work pieces. Further, by the difference of the peripheral speeds of the work piece, the inner part and the outer part of each work piece cannot be polished uniformly, and abrasion spots are sometimes formed in the work piece.
Since the gear teeth of the carriers
208
are engaged with the internal gear
204
and the sun gear
206
, abrasion dusts formed therebetween stick onto not only the carriers
208
but also polishing faces of the polishing plates
200
and
202
.
To solve the above described disadvantages, an improved polishing machine, which is capable of polishing both sides of work pieces without revolving and orbiting carriers, was disclosed in U.S. Pat. No. 6,080,048. It is shown in FIG.
18
.
In
FIG. 18
, an upper polishing plate
302
is rotated by a rotating unit
304
and vertically moved by a lifting unit
306
. A lower polishing plate
310
is rotated by a rotating unit
308
. One carrier
300
is sandwiched between the polishing plates
302
and
310
. A plurality of through-holes
230
, in each of which a work piece
100
is accommodated and held, are formed in the carrier
300
.
The carrier
300
has a plurality of holes bored along an outer edge. By inserting pins
316
, which are upwardly extended from a carrier holder
312
, into the holes, the carrier
300
can be attached to the carrier holder
312
.
The carrier holder
312
has a circular motion mechanism
320
. The circular motion mechanism
320
includes: four bearing sections
318
outwardly extended from an outer circumferential face of the carrier holder
312
; cranks respectively provided to the bearing sections
318
; and a driving unit
340
capable of synchronously driving the cranks.
Each of the cranks includes: a rotatable eccentric arm
324
formed into a circular disk; and a shaft
322
a
arranged parallel to axial lines of the polishing plates
302
and
310
and having one end attached to the bearing section
318
and the other end eccentrically attached to the circular eccentric arm
324
.
The driving unit
340
includes: shafts
322
b
, whose one ends are respectively attached to centers of the circular eccentric arms
324
; sprockets
342
respectively attached to the other ends of the shafts
322
b
; a timing chain engaged with the sprockets
342
; a gear
346
attached to one of the shafts
322
b
; a gear
350
engaged with the gear
346
; and a motor
348
for rotating the gear
350
.
In the polishing machine shown in
FIG. 18
, the polishing plates
302
and
310
are rotated in the predetermined directions by the motor
348
of the circular motion mechanism
320
. Therefore, the carrier holder
312
sandwiched between the polishing plates
302
and
310
performs small circular motion, without revolving on its own axis, in a plane including the carrier
300
. The peripheral speed differences of the carrier and the work pieces
100
, which are caused by revolution of the carrier, can be solved.
Unlike the polishing machine shown in
FIGS. 16 and 17
, the carrier
300
has no gear teeth engaging with the internal gear and the sun gear. Therefore, no abrasion dusts are formed and stuck onto the carrier
300
. Further, no abrasion dusts are stuck onto polishing faces of the polishing plates
302
and
310
.
However, in the polishing machine shown in
FIG. 18
, the center of the carrier
300
is shifted a distance “M” from a coaxial line “L” of the polishing plates
302
and
310
. The carrier
300
orbits around the line “L” without revolving its own axis. A radius of the circular orbit motion of the carrier
300
is equal to a distance between the shafts
322
a
and
322
b
(=”M”).
Since the carrier
300
, whose center is shifted the distance “M” from the line “L”, performs the circular orbit motion without revolving, centers of gravity of the work pieces held in the through-holes
230
of the carrier
300
are located at different positions with respect to a center of gravity or a center of rotation of the upper polishing plate
302
. Accordingly, uneven forces are applied to the work pieces
100
from the polishing plates
302
and
310
, vibrations are generated while polishing, and polishing accuracy is lowered.
Since the carrier
300
must be broader than the polishing faces of the polishing plates.
302
and
310
, the polishing machine must be large, and its manufacturing cost must be high. Namely, increasing efficiency by large-sized polishing machines is limited.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a compact polishing machine capable of evenly applying a pressing force from an upper polishing plate to work pieces accommodated in through-holes of carriers.
To solve the problems of the conventional polishing machines, the inventors studied and found that polishing efficiency can be improved, without employing the large carrier, by sandwiching a plurality of small carriers, each of which has through-holes for accommodating work pieces, between an upper polishing plate and a lower polishing plate.
Further, they found that small circular motion of the carriers can be performed, without revolving, by independently driving the carriers between the upper polishing plate and the lower polishing plate. By performing the small circular motion, the pressing force can be evenly applied from the upper polishing plate to the work pieces.
To achieve the object, the polishing machine of the present invention has following structures.
Namely, the polishing machine comprises:
an upper polishing plate for polishing upper faces of work pieces;
a lower polishing plate for polishing lower faces of the work pieces;
means for rotating at least one of the polishing plates;
a plurality of carriers being provided around a center of gravity of the upper polishing plate and sandwiched between the polishing plates, each of the carriers having a through-hole, in which the work piece is accommodated;
means for independently performing circular motion or swing motion of the carriers without revolving on their own axes; and
means for controlling the performing means,
whereby centers of gravity of the work pieces, which are held by the carriers, are simultaneously moved close to a center of gravity of the upper polishing plate and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces are equal while the circular motion or the swing motion of the carriers.
The polishing machine may further comprise means for orbiting the carriers round a rotational axis of the lower polishing plate, and the rotating means may rotate the both of said polishing plates. With this structure, accuracy of polishing the work pieces can be improved, the work pieces can be fed and taken out at fixed place or places, and the work pieces can be automatically fed and taken out by a robot, etc.
Another polishing machine comprises:
a fixed upper polishing plate for polishing upper faces of work pieces;
a rotatable lower polishing plate for polishing lower faces of the work pieces;
means for rotating the lower polishing plate;
a plurality of carriers being provided around a center of gravity of the upper polishing plate and sandwiched between the polishing plates, each of the carriers having a through-hole, in which the work piece is accommodated;
means for independently performing circular motion or swing motion of the carriers without revolving on their own axes;
means for orbiting the carriers round a rotational axis of the lower polishing plate; and
means for controlling the performing means,
whereby centers of gravity of the work pieces, which are held by the carriers, are simultaneously moved close to a center of gravity of the upper polishing plate and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces are equal while the circular motion or the swing motion of the carriers.
In the polishing machine, the performing means may be located close to the lower polishing plate; and connecting sections, which are respectively formed in extended sections of the carriers projected from an outer edge of the lower polishing plate, may be respectively connected with connecting members of the performing means. With this structure, the circular motion or the swing motion of the carriers can be performed without revolving on their own axes.
In the polishing machine, the lower polishing plate may have a donut-shape with a center hole; a couple of the performing means may be respectively located close to an inner circumferential face of the center hole of the lower polishing plate and an outer circumferential face of the lower polishing plate; and connecting sections, which are formed in the carriers and located close to the inner circumferential face and the outer circumferential face of the lower polishing plate, may be respectively connected with connecting members of the performing means. With this structure, the circular motion or the swing motion of the carriers can be easily performed without revolving on their own axes.
In the polishing machine, the performing means may include eccentric arms, which are rotatable and in each of which a connecting pin connected with the carrier is eccentrically provided. With this structure, the circular motion or the swing motion of the carriers can be easily performed without revolving on their own axes.
In the polishing machine, the performing means may includes: eccentric arms, which are rotatable and in each of which a first connecting pin connected with the carrier is eccentrically provided; and swing arms, which are swingable and in each of which a second connecting pin is connected with the carrier at a position separated from the first connecting pin. With this structure, the swing motion of the carriers can be performed.
In the polishing machine, phases of the circular motion or the swing motion of the carriers provided to the lower polishing plate may be same, or an even number of the carriers may be provided to the lower polishing plate and the phases of the circular motion or the swing motion of the adjacent carriers may be shifted 180 degrees. With this structure, pressing force can be evenly applied from the upper polishing plate to the work pieces held or accommodated in the through-holes of the carriers.
In the polishing machine, each of the carriers may have a plurality of the through-holes. Further, each of the carriers may be formed into a diamond shape or a sector shape.
In the polishing machine of the present invention, a plurality of the carriers, which hold the work pieces, are sandwiched between the upper polishing plate and the lower polishing plate, so small-sized carriers may be employed. Therefore, a compact polishing machine, whose size is not limited by carriers, can be realized.
Further, the control means controls the performing means to simultaneously move the centers of gravity of the work pieces close to the center of gravity of the upper polishing plate and to simultaneously move the same away therefrom, and to make the moving distances of the centers of gravity of the work pieces equal while the circular motion or the swing motion of the carriers. With this control, a pressing force can be evenly applied from the upper polishing plate to the work pieces held or accommodated in the through-holes of the carriers. Therefore, accuracy of polishing the work pieces can be improved.
Especially, in the case of orbiting the carriers around a rotational axis of the lower polishing plate, the polishing accuracy can be further improved.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which:
FIG. 1
is a schematic view of a polishing machine of an embodiment the present invention;
FIG. 2A
is a front view of a carrier employed in the polishing machine shown in
FIG. 1
;
FIG. 2B
is a sectional view of the carrier employed in the polishing machine shown in
FIG. 1
;
FIG. 3
is a sectional view of one of performing means employed in the polishing machine shown in
FIG. 1
;
FIG. 4
is a sectional view of the other performing means employed in the polishing machine shown in
FIG. 1
;
FIG. 5
is a partial sectional view of a extended from an eccentric arm;
FIG. 6
is a plan view of carriers provided on the lower polishing plate;
FIGS. 7A and 7B
are explanation views showing motion of the carriers shown in
FIG. 6
;
FIG. 8
is a front view of another carrier employed in the polishing machine shown in
FIG. 1
;
FIGS. 9A and 9B
are partial sectional views of the carrier shown in
FIG. 8
;
FIG. 10
is a plan view of other carriers provided on the lower polishing plate;
FIG. 11
is a plan view of other carriers provided on the lower polishing plate;
FIGS. 12A and 12B
are plan views of the polishing machine of another embodiment of the present invention;
FIGS. 13A and 13B
are plan views of the polishing machine of another embodiment of the present invention;
FIG. 14
is a front view of the carrier shown in
FIGS. 13A and 13B
;
FIG. 15
is a partial sectional view of the carrier shown in
FIGS. 13A and 13B
;
FIG. 16
is a schematic view of the conventional polishing machine;
FIG. 17
is a front view of the carriers provided on the lower polishing plate of the conventional polishing machine; and
FIG. 18
is a schematic view of another conventional polishing machine.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
A polishing machine of an embodiment the present invention is shown in FIG.
1
. The polishing machine has an upper polishing plate
10
, which rotates in a prescribed direction, and a lower polishing plate
12
, which is formed into a donut shape. The lower polishing plate
12
is mounted on a lower board
14
. With this structure, the lower polishing plate
12
is rotated together with the lower board
14
when the lower board
14
is rotated. The lower board
14
is rotatably mounted on a base
18
with a bearing
16
. Torque of an electric motor
24
, which rotates the lower board
14
, is transmitted to the lower board
14
by transmission gears
20
and a cylindrical shaft
22
. In
FIG. 1
, the torque of the motor
24
is transmitted to the gears
20
by a belt.
The upper polishing plate
10
is rotated by an electric motor
99
and vertically moved by a proper unit, e.g., a cylinder unit.
In
FIG. 1
, a plurality of carriers
26
for holding work pieces “W” are mounted on the donut-shaped lower polishing plate
12
having a center hole
15
. As shown in
FIGS. 2A and 2B
, the carrier
26
is formed into a diamond shape and made of epoxy resin including glass fibers as a reinforcing material. A through-hole
28
for accommodating and holding the work piece “W” is formed at a center of the carrier
26
. Extended sections
26
a
are rightwardly and leftwardly extended from the through-hole
28
, and they are projected from an inner edge of the center hole
15
and an outer edge of the lower polishing plate
12
. Small holes
26
b
are respectively formed at outer end parts of the extended sections
26
a
. The small holes
26
b
act as connecting sections, which are connected with a pair of means
30
and
40
for performing circular motion or swing motion of the carriers
26
.
The performing means
30
is located close to an outer circumferential face of the lower polishing plate
12
(see FIG.
1
). As shown in
FIG. 3
, the performing means
30
includes: an eccentric arm
34
; a connecting pin
32
eccentrically provided in one face of the eccentric arm
34
; a rotary shaft
36
having one end fixed at a center of the other face of the eccentric arm
34
and being inserted in a cylindrical casing
35
with bearings
37
; and a gear
38
fixed to the other end of the rotary shaft
36
. The connecting pin
32
of the performing means
30
is inserted into one of the small holes
26
b
of the carrier
26
(see FIGS.
2
A and
2
B).
The performing means
40
is located close to an inner circumferential face of the center hole
15
of the lower polishing plate
12
(see FIG.
1
). As shown in
FIG. 4
, the performing means
40
includes: an eccentric arm
44
; a connecting pin
42
eccentrically provided in one face of the eccentric arm
44
; a rotary shaft
46
having one end fixed at a center of the other face of the eccentric arm
44
and being inserted in a cylindrical casing
45
with bearings
47
; and a gear
48
fixed to the other end of the rotary shaft
46
. The connecting pin
42
of the performing means
40
is inserted into the other small hole
26
b
of the carrier
26
(see FIGS.
2
A and
2
B).
As shown in
FIG. 5
, the connecting pin
32
(
42
), which is vertically extended from the eccentric arm
34
(
44
) of the performing means
30
(
40
), comprises: a vertical screw
31
fixed to the eccentric arm
34
(
44
); a cap member
39
rotatably covering the vertical screw
31
; and a flange
33
fixed to the vertical screw
31
so as to limit a movement of the cap member
39
in the axial direction thereof.
As shown in
FIG. 1
, a pair of the performing means
30
and
40
are provided for each carrier
26
mounted on the lower polishing plate
26
. A plurality of the performing means
30
are located close to the outer circumferential face of the lower polishing plate
12
and arranged along the outer edge thereof.
The gears
38
of the performing means
30
are engaged with a gear
54
of a transmission mechanism
50
, which transmits torque of a servo motor
52
to the gears
38
. With this structure, rotational directions and rotational speeds of the eccentric arms
34
of the performing means
30
can be synchronized by the servo motor
52
.
A plurality of the performing means
40
are located close to the inner circumferential face of the center hole
15
of the lower polishing plate
12
and arranged along the inner edge thereof.
The gears
48
of the performing means
40
are engaged with a gear
66
via a transmission mechanism
62
and a cylindrical shaft
64
, which transmits torque of a servo motor
60
to the gears
48
. With this structure, rotational directions and rotational speeds of the eccentric arms
44
of the performing means
40
can be synchronized by the servo motor
60
.
A first control section
96
controls the servo motors
52
and
60
so as to rotate the eccentric arms
34
of the performing means
30
, which are synchronized by the gear
54
, and the eccentric arms
44
of the performing means
40
, which are synchronized by the gear
66
, in the same rotational direction at the same rotational speed.
In
FIG. 1
, a plurality of the performing means
30
, which are arranged along the outer edge of the lower polishing plate
12
, are fixed to a plate
72
, which is rotated by a servo motor
70
. With this structure, the performing means
30
moves along the outer edge of the circular lower polishing plate
12
together with the plate
72
when the servo motor
70
is turned on.
A plurality of the performing means
40
, which are arranged along the inner edge of the center hole
15
of the lower polishing plate
12
, are fixed to a plate
84
, which is fixed to an upper end of a shaft
82
rotated by a servo motor
80
. With this structure, the performing means
40
moves along the inner edge of the circular lower polishing plate
12
together with the plate
84
when the servo motor
80
is turned on.
A second control section
98
controls the servo motors
70
and
80
so as to orbit the carriers
26
, in each of which the connecting pins
32
and
42
of the eccentric arms
34
and
44
of the performing means
30
and
40
have been inserted in the small holes
26
b
, round the rotational axis of the lower polishing plate
12
.
In the polishing machine shown in
FIG. 1
, the upper polishing plate
10
and the lower polishing plate
12
are rotated in the prescribed directions, thus the carriers
26
are orbited round the rotational axis of the lower polishing plate
12
so as to improve accuracy of polishing the work pieces “W” held by the carriers
26
. Note that, if the improvement of polishing accuracy is not required, the orbital movement of the carriers
26
may be omitted.
In the case of polishing without orbiting the carriers
26
, the carriers
26
may be orbited so as to adjust positions of the carriers
26
after completion of the polishing work. By adjusting the positions of the carriers
26
, the polished work pieces “W” can be positioned at predetermined positions together with the carriers
26
, so that the polished work pieces “W” can be automatically taken out from the carriers
26
and other work pieces to be newly polished can be automatically set in the carriers
26
by an automatic mechanism, e.g., a robot.
The upper polishing plate
10
applies a pressing force to the work pieces “W”, which have been accommodated and held in the through-holes
28
of the carriers
26
and sandwiched between the polishing plates
10
and
12
. Therefore, concave sections, which correspond to the performing means
40
arranged along the inner edge of the lower polishing plate
12
, are formed in the upper polishing plate
10
.
The control section
96
controls the servo motors
52
and
60
so as to rotate the eccentric arms
34
of the performing means
30
and the eccentric arms
44
of the performing means
40
in the same direction at the same rotational speed.
Since the connecting pins
32
and
42
of the eccentric arms
34
and
44
of the performing means
30
and
40
are inserted in the small holes
26
b
of each carrier
26
, each carrier
26
can be moved to perform small circular motion without revolving on its own axis.
In the polishing machine shown in
FIG. 1
, the carriers
26
are mounted on the lower polishing plate
12
and arranged to enclose a center of gravity (mass) of the upper polishing plate
10
. Each carrier
26
is connected with each pair of the performing means
30
and
40
by inserting the connecting pins
32
and
34
of the eccentric arms
34
and
44
into the small holes
26
b
, and distances from the center of gravity of the upper polishing plate
10
to centers of gravity of the work pieces “W” held in the through-holes
28
of the carriers
26
are equal.
The first control section
96
controls the servo motors
52
and
60
so as to rotate the eccentric arms
34
and
44
of the performing means
30
and
40
, so that small circular motion of the carriers
26
without revolving their own axes can be performed in the same direction at the same rotational speed.
While the small circular motion of the carriers
26
without revolution, the carriers
26
are simultaneously moved close to the center of gravity of the upper polishing plate
10
and simultaneously moved away therefrom, and moving distances of the carriers
26
are equal, so that centers of gravity of the work pieces “W”, which are held by the carriers
26
, are simultaneously moved close to the center of gravity of the upper polishing plate
10
and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces “W” are equal. Namely, distances from the center of gravity of the upper polishing plate
10
from the centers of gravity of the work pieces “W” are always equal.
Note that, the electric motors
24
and
25
are controlled by other control sections (not shown) separated from the control sections
96
and
98
.
Next, action of the five carriers
26
mounted on the lower polishing plate
12
will be explained with reference to
FIGS. 6
,
7
A and
7
B.
The five carriers
26
are provided on the lower polishing plate
12
and arranged to enclose the center of gravity of the upper polishing plate
10
. The carriers
26
are shown in
FIGS. 2A and 2B
, and the work pieces “W” are respectively accommodated and held in the through-holes
28
. As shown in
FIG. 6
, the connecting pin
32
and
42
of the eccentric arms
34
and
44
of the performing means
30
and
40
are respectively inserted in the small holes
26
a
of the carriers
26
. Since the carriers
26
are connected with the performing means
30
and
40
by the connecting pins
32
and
42
, the distances from the center of gravity of the upper polishing plate
10
to the centers of gravity of the work pieces “W” held by the carriers
26
are equal.
By moving the upper polishing plate
10
downward, the work pieces “W” held by the carriers
26
are sandwiched between the upper polishing plate
10
and the lower polishing plate
12
. When the motor
24
is started, the lower polishing plate
12
is rotated in a direction “A”, and the upper polishing plate
10
is rotated in a prescribed direction.
Simultaneously, the servo motors
52
and
60
are started so as to rotate the eccentric arms
34
and
44
of the performing means
30
and
40
in the same direction.
Since the gears
38
of the eccentric arms
34
of the performing means
30
, which are located close to the outer circumferential face of the lower polishing plate
12
, are engaged with the gear
54
rotated by the motor
52
, the eccentric arms
34
are synchronously rotated in a direction indicated by arrows.
Since the gears
48
of the eccentric arms
44
of the performing means
40
, which are located close to the inner circumferential face of the lower polishing plate
12
, are engaged with the gear
66
rotated by the motor
60
, the eccentric arms
44
are synchronously rotated in a direction indicated by arrows.
Since the motors
52
and
60
are controlled by the first control sections
96
, the eccentric arms
34
and
44
of each carrier
26
can be rotated in the same direction at the same rotational speed.
Note that, in the example shown in
FIG. 6
, the eccentric arms
34
and
44
rotate in the clockwise direction at the same rotational speed. Therefore, the carriers
26
, which are connected with the eccentric arms
34
and
44
by the connecting pins
32
and
42
, can perform the small circular motion, without orbiting, in the clockwise direction.
For example, the carriers
26
connected with the eccentric arms
34
and
44
are rotated in the clockwise direction and simultaneously moved toward the center of the lower polishing plate
12
(See FIG.
7
A). Therefore, the work pieces “W” held in the through-holes
28
of the carriers
26
are moved close to the inner edge of the donut-shaped lower polishing plate
12
(see FIG.
7
B).
By further rotating the eccentric arms
34
and
44
in the clockwise direction, the carriers
26
rotate in the clockwise direction and simultaneously moved toward the outer edge of the lower polishing plate
12
, so that the work pieces “W” held in the through-holes
28
of the carriers
26
are moved close to the outer edge of the lower polishing plate
12
.
The small circular motion of the carriers
26
, without revolving their own axes, are synchronously performed, so that the distances from the center of gravity of the upper polishing plate
10
to the centers of gravity of the work pieces “W” held in the through-holes
28
of the carriers
26
are equal. The center of gravity of the upper polishing plate
10
corresponds to the rotational axis of the lower polishing plate
12
.
Therefore, a pressing force can be evenly applied to the work pieces “W” while polishing them between the polishing plates
10
and
12
.
By evenly applying the pressing force, the problems of the conventional polishing machines, e.g., uneven polishing, generating vibrations, low polishing accuracy, can be solved.
In the polishing machine shown in
FIG. 1
, the second control section
98
controls the servo motors
70
and
80
, and the performing means
30
and
40
for each carrier
26
are orbited round the rotational axis of the lower polishing plate
12
, so that the work pieces “W” held in the through-holes
28
of the carriers
26
are also orbited round the rotational axis of the lower polishing plate
12
. Therefore, conditions of the polishing faces of the polishing plates
10
and
12
do not influence polishing accuracy, so that the work pieces “W” can be polished with high polishing accuracy.
After completion of polishing the work pieces “W”, the rotation of the upper polishing plate
10
is stopped, then the upper polishing plate
10
is moved upward so as to take out the polished work pieces “W”. At that time, the second control section
98
controls the servo motors
70
and
80
, and, the performing means
30
and
40
for each carrier
26
are orbited round the rotational axis of the lower polishing plate
12
, so that the carriers
26
are also orbited round the rotational axis of the lower polishing plate
12
. When the predetermined carrier
26
reaches a take-out position, the orbital movement of the carriers
26
is stopped.
At the take-out position, the polished work piece “W” held in the predetermined carrier
26
is taken out, then the carriers
26
are orbited again until the next carrier
26
holding the polished work piece “W” reaches the take-out position. This action is repeated until all the work pieces “W” are taken out from the carriers
26
.
In the above description, both of the upper polishing plate
10
and the lower polishing plate
12
are rotated to polish the work pieces “W”.
In another embodiment, the work pieces “W” may be polished between the upper polishing plate
10
, which is not rotated, and the lower polishing plate
12
, which is rotated. In this case, the carriers
26
must be orbited round the rotational axis of the lower polishing plate
12
while polishing the work pieces “W”.
By driving the servo motors
70
and
80
, the plates
72
and
84
are rotated, so that the orbital movement of the carriers
26
can be executed. At that time, the second control section
98
controls the motors
70
and
80
to orbit the performing means
30
and
40
, which are provided for each carrier
26
, round the rotational axis of the lower polishing plate
12
. The second control section
98
controls rotational speeds of the plates
72
and
84
, too.
By orbiting the carriers
26
holding the work pieces “W” while polishing, the upper polishing plate
10
need not be rotated, so the means
99
for rotating the upper polishing plate
10
can be omitted. Namely, the structure of the polishing machine can be simple.
The carrier
26
shown in
FIGS. 2A and 2B
is made of epoxy resin including glass fibers as a reinforcing material. As described above, the extended sections
26
a
are rightwardly and leftwardly extended from the through-hole
28
, and the small holes
26
b
are respectively formed in the extended sections
26
a.
To easily handle the carriers
26
, they are made thin and light. However, if the connecting pins
32
and
42
are inserted in the small holes
26
b
of the thin carriers
26
and the eccentric arms
34
and
44
are rotated, inner edges of the small holes
26
b
are sometimes damaged by the connecting pins
32
and
42
, or outer circumferential faces of the connecting pins
32
and
42
are sometimes damaged by the inner edges of the small holes
26
b
. To solve the problem, reinforcing plates
25
, each of which has a through-hole
25
a
whose diameter is equal to that of the small hole
26
b
, may be adhere on the carrier
26
(see FIGS.
8
and
9
A). By the reinforcing plates
25
, the inner edges of the small holes
26
b
can be reinforced, so that they are not damaged by the connecting pins
32
and
42
inserted there through.
Since the outer circumferential faces of the connecting pins
32
and
42
contact inner circumferential faces of the small holes
26
b
and the through-holes
25
a
, shock of contacting the both faces can be scattered, so that the damage of the inner edges of the small holes
26
b
and the outer circumferential faces of the connecting pins
32
and
42
can be prevented.
Further, as shown in
FIG. 9B
, the inner circumferential faces of the small hole
26
b
and the through-hole
25
a
, which contact the connecting pins
32
(or
42
), may be reinforced by inserting and fixing cylindrical member
27
a
in the both holes
26
b
and
25
a
. In an example shown in
FIG. 9B
, the reinforcing plate
25
, whose through-hole
25
a
is a female screw hole, is previously adhered on an upper face of the carrier
26
. The cylindrical member
27
a
is upwardly extended from a flange section
27
b
, and a male screw is formed on an outer circumferential face thereof. The cylindrical member
27
a
is inserted into the small hole
25
a
from a bottom side of the carrier
26
and screwed with the female screw hole
25
a
of the reinforcing plate
25
. With this structure, the inner faces and the inner edges of the small holes
26
b
can be reinforced.
In the polishing machine shown in
FIGS. 6
,
7
A and
7
B, an odd number of the carriers
26
are provided on the lower polishing plate
12
. On the other hand, in the polishing machine shown in
FIG. 10
, an even number of the carriers
26
are provided on the lower polishing plate
12
. In this case too, a pair of the performing means
30
and
40
are required for each carrier
26
.
In
FIG. 10
, phases of the small circular motion of the carriers
26
are same. On the other hand, in the polishing machine shown in
FIG. 11
, phases of the circular motion of the adjacent carriers
26
are shifted 180 degrees. Since an even number of the carriers
26
are provided, the carriers
26
whose phases of the circular motion are mutually same are alternately arranged. With this arrangement, the carriers
26
can be mutually balanced. Further, in this case, the distances from the center of gravity of the upper polishing plate
10
to the centers of gravity of the work pieces “W” held in the carriers
26
, whose phases of the circular motion are same, are equal. The center of gravity of the upper polishing plate
10
corresponds to the rotational axis of the lower polishing plate
12
.
In each of the polishing machines shown in
FIGS. 1-11
, the carriers
26
provided on the lower polishing plate
12
perform the small circular motion. The performing means
40
, which are arranged along the inner edged of the center hole
15
of the lower polishing plate
12
, should be provided for each carrier
26
. Therefore, if a number of the carriers
26
is increased, the center hole
15
must be broadened so as to install the increased number of the performing means
40
therein. However, the upper polishing plate
10
and the lower polishing plate
12
must have the polishing faces having prescribed area, so the polishing plates
10
and
12
must be large with broadening the center hole
15
. To include the large polishing plates
10
and
12
, the polishing machine must be large in size.
To solve this problem, a polishing machine shown in
FIG. 12A
has a swing mechanism
76
provided in the center hole
15
of the lower polishing plate
12
. Unlike the polishing machine having a plurality of the performing means
40
provided in the center hole
15
, the center hole
15
can be small in size.
A plurality of swing arms
77
, which swing in directions “B” are included in the swing mechanism
76
. Number of the swing arms
77
is equal to that of the carriers
26
provided on the lower polishing plate
12
. Second connecting pins
79
, each of which is inserted in the small hole
26
b
of the carrier
26
, are respectively provided to front ends of the swing arms
77
.
A plurality of performing means
30
are arranged along the outer edge of the lower polishing plate
12
. Each performing means
30
corresponds to each carrier
26
as well as the foregoing embodiments.
By adjusting swing speeds of the swing arms
77
and rotational speeds of the eccentric arms
34
, swing motion of the carriers
26
can be performed.
When the work pieces “W”, which are accommodated and held in the through-holes
28
, are located close to the outer edge of the lower polishing plate
12
rotating in a direction “A” (see FIG.
12
A), the eccentric arms
34
of the performing means
30
are rotated in the clockwise direction, and the swing arms
77
of the swing mechanism
76
are turned in the clockwise direction. At that time, the work pieces “W” held by the carriers
26
are moved toward the center hole
15
and simultaneously moved in the clockwise direction. When the clockwise turn of the swing arms
77
are stopped, the work pieces “W” are located close to the inner edge of the center hole
15
of the lower polishing plate
12
(see FIG.
12
B).
Then, the swing arms
77
of the swing mechanism
76
are turned in the counterclockwise direction, and the eccentric arms
34
are continuously rotated in the clockwise direction. When the counterclockwise turn of the swing arms
77
are stopped, the work pieces “W” are located close to the outer edge of the lower polishing plate
12
(see FIG.
12
A).
Since the carriers
26
are synchronously moved, the distances from the center of gravity of the upper polishing plate
10
to the centers of gravity of the work pieces “W” held in the through-holes
28
of the carriers
26
are equal, and the center of gravity of the upper polishing plate
10
corresponds to the rotational axis of the lower polishing plate
12
(see FIGS.
12
A and
12
B).
Therefore, the pressing force from the polishing plate
10
can be evenly applied to the work pieces “W”, which are polished between the polishing plates
10
and
12
.
In the above described embodiments, the carrier
26
is formed into the diamond shape, but it may be formed into a sector or fan shape (see FIGS.
13
A and
13
B).
In
FIG. 13A
, the work pieces “W” held in the through-holes
28
of the sector-shaped carriers
26
are located close to the outer edge of the lower polishing plate
12
; in
FIG. 13B
, the work pieces “W” held in the through-holes
28
of the sector-shaped carriers
26
are located close to the inner edge of the lower polishing plate
12
. Note that, in
FIGS. 13A and 13B
, the structural elements shown in
FIGS. 1-12B
are assigned the same symbols, and explanation of them will be omitted.
Enlarged view of the sector-shaped carrier
26
is shown in FIG.
14
. The through-hole
28
for accommodating the work piece “W” is formed at a center part. The small holes
26
b
are formed along an inner edge and an outer edge of the sector-shaped carrier
26
.
The connecting pins
32
shown in
FIG. 15
are respectively inserted into the small holes
26
b
arranged along the outer edge. The connecting pins
32
are provided to a band-shaped member
58
, which are arranged along the outer edge of the carrier
26
. The connecting pins
32
correspond to the small holes
26
b
arranged along the outer edge of the carrier
26
.
As shown in
FIG. 15
, the band-shaped member
58
is formed into an L-shape in section and fixed to a circular disk
56
, which is rotatably attached to a pin
55
with a bearing
56
b
. The pin
55
is eccentrically provided to the circular eccentric arm
34
.
As shown in
FIG. 14
, the connecting pins
42
are respectively inserted into the small holes
26
b
arranged along the inner edge. The connecting pins
42
are provided to a band-shaped member
59
, which are arranged along the inner edge of the carrier
26
. The connecting pins
42
correspond to the small holes
26
b
arranged along the inner edge of the carrier
26
. The band-shaped member
59
is formed into an L-shape in section and fixed to a circular disk
57
, which is rotatably attached to a pin, which is eccentrically provided to the circular eccentric arm
44
, with a bearing.
In the polishing machine having the sector-shaped carriers
26
shown in
FIGS. 13A-15
, when the eccentric arms
34
and
44
are rotated in the clockwise direction at the same speed (see FIGS.
6
-
7
B), the carriers
26
connected by the connecting pins
32
of the band-shaped members
58
and
59
perform the small circular motion, in the clockwise direction, without orbiting.
Since the connecting pins
32
and
42
are inserted in the small holes
26
b
arranged along the inner and the outer edges of the carrier
26
, an external force is applied to the carrier
26
via the connecting pins
32
and
42
, so that the external force is scattered. Therefore, unlike the carrier
26
engaged with one connecting pin
32
and one connecting pin
42
, damage of the carrier
26
can be prevented; no reinforcing means
25
(see
FIGS. 8-9B
) are provided to the small holes
26
b
. Of course, the reinforcing means
25
may be employed to further reinforce the carriers
26
.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by he foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims
- 1. A polishing machine, comprising:an upper polishing plate for polishing upper faces of work pieces; a lower polishing plate for polishing lower faces of the work pieces; means for rotating at least one of said polishing plates; a plurality of carriers being provided around a center of gravity of said upper polishing plate and sandwiched between said polishing plates, each of said carriers having a through-hole, in which the work piece is accommodated; means for independently performing circular motion or swing motion of said carriers without revolving on their own axes; and means for controlling said performing means, whereby centers of gravity of the work pieces, which are held by said carriers, are simultaneously moved close to a center of gravity of said upper polishing plate and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces are equal while the circular motion or the swing motion of said carriers.
- 2. The polishing machine according to claim 1,further comprising means for orbiting said carriers round a rotational axis of said lower polishing plate, wherein said rotating means rotates the both of said polishing plates.
- 3. The polishing machine according to claim 1,wherein said performing means is located close to said lower polishing plate, and connecting sections, which are respectively formed in extended sections of said carriers projected from an outer edge of said lower polishing plate, are respectively connected with connecting members of said performing means.
- 4. The polishing machine according to claim 1,wherein said lower polishing plate has a donut-shape with a center hole, a couple of said performing means are respectively located close to an inner circumferential face of the center hole of said lower polishing plate and an outer circumferential face of said lower polishing plate, and connecting sections, which are formed in said carriers and located close to the inner circumferential face and the outer circumferential face of said lower polishing plate, are respectively connected with connecting members of said performing means.
- 5. The polishing machine according to claim 1,wherein said performing means includes eccentric arms, which are rotatable and in each of which a connecting pin connected with said carrier is eccentrically provided.
- 6. The polishing machine according to claim 1,wherein said performing means includes: eccentric arms, which are rotatable and in each of which a first connecting pin connected with said carrier is eccentrically provided; and swing arms, which are swingable and in each of which a second connecting pin is connected with said carrier at a position separated from said first connecting pin.
- 7. The polishing machine according to claim 1,wherein phases of the circular motion or the swing motion of said carriers provided to said lower polishing plate are same.
- 8. The polishing machine according to claim 1,wherein an even number of said carriers are provided to said lower polishing plate, and phases of the circular motion or the swing motion of said adjacent carriers are shifted 180 degrees.
- 9. The polishing machine according to claim 1,wherein each of said carriers has a plurality of the through-holes.
- 10. The polishing machine according to claim 1,wherein each of said carriers is formed into a diamond shape or a sector shape.
- 11. A polishing machine, comprising:a fixed upper polishing plate for polishing upper faces of work pieces; a rotatable lower polishing plate for polishing lower faces of the work pieces; means for rotating said lower polishing plate; a plurality of carriers being provided around a center of gravity of said upper polishing plate and sandwiched between said polishing plates, each of said carriers having a through-hole, in which the work piece is accommodated; means for independently performing circular motion or swing motion of said carriers without revolving on their own axes; means for orbiting said carriers round a rotational axis of said lower polishing plate; and means for controlling said performing means, whereby centers of gravity of the work pieces, which are held by said carriers, are simultaneously moved close to a center of gravity of said upper polishing plate and simultaneously moved away therefrom, and moving distances of the centers of gravity of the work pieces are equal while the circular motion or the swing motion of said carriers.
- 12. The polishing machine according to claim 11,wherein said performing means is located close to said lower polishing plate, and connecting sections, which are respectively formed in extended sections of said carriers projected from an outer edge of said lower polishing plate, are respectively connected with connecting members of said performing means.
- 13. The polishing machine according to claim 11,wherein said lower polishing plate has a donut-shape with a center hole, a couple of said performing means are respectively located close to an inner circumferential face of the center hole of said lower polishing plate and an outer circumferential face of said lower polishing plate, and connecting sections, which are formed in said carriers and located close to the inner circumferential face and the outer circumferential face of said lower polishing plate, are respectively connected with connecting members of said performing means.
- 14. The polishing machine according to claim 11,wherein said performing means includes eccentric arms, which are rotatable and in each of which a connecting pin connected with said carrier is eccentrically provided.
- 15. The polishing machine according to claim 11,wherein said performing means includes: eccentric arms, which are rotatable and in each of which a first connecting pin connected with said carrier is eccentrically provided; andswing arms, which are swingable and in each of which a second connecting pin is connected with said carrier at a position separated from said first connecting pin.
- 16. The polishing machine according to claim 11,wherein phases of the circular motion or the swing motion of said carriers provided to said lower polishing plate are same.
- 17. The polishing machine according to claim 11,wherein an even number of said carriers are provided to said lower polishing plate, and phases of the circular motion or the swing motion of said adjacent carriers are shifted 180 degrees.
- 18. The polishing machine according to claim 11,wherein each of said carriers has a plurality of the through-holes.
- 19. The polishing machine according to claim 11,wherein each of said carriers is formed into a diamond shape or a sector shape.
Priority Claims (2)
Number |
Date |
Country |
Kind |
2002-251381 |
Aug 2002 |
JP |
|
2003-292132 |
Aug 2003 |
JP |
|
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Jun 2000 |
A |
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Hakomori |
Sep 2000 |
A |
6206765 |
Sanders et al. |
Mar 2001 |
B1 |
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Number |
Date |
Country |
2002-36099 |
Feb 2002 |
JP |