JPH05261652A - Bore inner surface polisher - Google Patents

Abstract

PURPOSE:To provide a bore inner surface polisher that is able to finish the inner circumferential surface smoothly even if a work hole formed in a work forming a round bar form of brittle material, etc., is in an eccentric state. CONSTITUTION:This polisher is provided with two work holding means 13, 15 holding a cylindrical work formed with a work hole 16, three work rotating means 17, 19, 20 rotating the work hole 16 as the center together with the work 14, and a bar abrasive member 30 being inserted into this work hole 16. Also it is provided with two abrasive member supporting means 31, 37 supporting this abrasive member 30 free of rotation, two abrasive member energizing means 28, 36 energizing these abrasive member supporting means 31, 37 to an inner circumferential surface of the work hole 16 together with the abrasive member 30, and an abrasive member rotating means 29 being connected to the abrasive member 30 and driving and rotating this abrasive member 30, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for finishing the inner peripheral surface of a hole formed in a hard and brittle material to be smooth, and in particular, a hole for inserting a pair of stress applying members is formed in an eccentric state. It is suitable for use as a base material for polarization-maintaining optical fibers to be the clad portion.

[0002]

2. Description of the Related Art An optical fiber for single mode transmission composed of a core portion and a cladding portion whose refractive indexes are different stepwise has a tendency that the thickness of the cladding portion becomes very large relative to the diameter of the core portion. Have. In order to efficiently produce an optical fiber having such a structure, or a polarization mode maintaining optical fiber in which a plurality of stress applying portions sandwiching the central core portion are symmetrically arranged around the core portion, a core member or A rod-shaped core serving as a core portion or a stress imparting portion for the optical fiber preform is prepared in advance by preparing a round rod-shaped optical fiber preform that serves as a clad portion in which a hole for inserting a stress applying member is formed. It is considered effective to insert a member or a stress applying member, heat and integrate these members, and then draw the wire.

When the optical fiber is manufactured by such a method, the inner peripheral surface of the hole for inserting the core member or the stress applying member formed in the optical fiber preform which becomes the clad portion must be made smooth beforehand. When a rod-shaped core member or a stress applying member to be the core part or the stress applying part is inserted and they are integrated by heating, a small amount is formed on the interface between the core part and the clad part or the interface between the stress applying part and the clad part. As a result of the inclusion of such bubbles, the transmission loss of the resulting optical fiber is significantly increased.

Therefore, a polishing apparatus for finishing the inner peripheral surface of the hole for inserting the core member or the stress applying member formed in the optical fiber preform to be the clad portion to be smooth is disclosed in Japanese Patent Laid-Open No. 3-75232. Etc. have been proposed.

FIG. 11 showing the side shape of the polishing apparatus disclosed in Japanese Patent Laid-Open No. 3-75232 and its XII-XII.
As shown in FIG. 12 showing a sectional structure in the direction of the arrow, a work table 2 rotatably driven on a bed 1 has a cylindrical optical fiber preform 4 in which a hole 3 for inserting a core portion is formed. Are fixed vertically upward through the scroll chuck 5. A tool for rotatably supporting a polishing brush 8 to be inserted into a hole 3 for inserting a core portion of an optical fiber preform 4 is provided at a tip end portion of an ascending / descending arm 7 provided so as to be capable of ascending / descending with respect to the column 6. The chuck 9 is attached.

Countless polishing grains (not shown) are fixed to the polishing brush 8 coaxial with the work table 2, and the polishing brush 8 is inserted into the hole 3 for inserting the core portion with elastic deformation. The inner peripheral surface of the hole 3 for inserting the core portion is smoothly polished by the relative rotational movement with the optical fiber preform 4 mounted on the work table 2.

[0007]

According to the knowledge of the present inventors, in order to prevent bubbles from being generated at the interface between the core portion and the cladding portion after drawing, the inner peripheral surface of the hole 3 for inserting the core portion is formed. It is desirable that the surface roughness of the center line average roughness _Ra be 0.1 μm or less.

However, in the case of the conventional polishing apparatus as shown in FIGS. 11 and 12, a sufficient polishing pressure cannot be generated only by the processing pressure associated with the elastic deformation of the polishing brush 8, and the polishing brush 8 The shaft itself of the polishing brush 8 swirls due to insufficient rigidity with high-speed rotation, and the inside of the hole 3 for inserting the core portion of the optical fiber preform 4 formed of quartz glass or the like which is a hard and brittle material It was difficult to finish it sufficiently smooth for things such as the peripheral surface. Therefore, although the inner peripheral surface of the hole 3 for inserting the core portion formed in the optical fiber preform 4 is polished, the interface between the core portion and the clad portion of the optical fiber after drawing is The generated bubbles cannot be completely removed, and it is difficult to significantly reduce the transmission loss defects.

Further, the conventional polishing apparatus shown in FIGS. 11 and 12 is only applicable to the optical fiber preform 4 having the core member insertion hole 3 formed coaxially, and a plurality of stress applying portions are provided in the core. It is impossible to machine the inner peripheral surface of the hole for inserting the stress imparting member that is eccentric with respect to the optical fiber preform such as the polarization mode maintaining optical fiber symmetrically arranged around the portion.

[0010]

It is an object of the present invention to provide a surface roughness of the inner peripheral surface of a round bar-shaped work such as a hard brittle material even if the hole is eccentric. 0.1μ in _a
It is an object of the present invention to provide a hole inner surface polishing apparatus that can be finished to m or less.

[0011]

A hole inner surface polishing apparatus according to the first aspect of the present invention is a work holding means for holding a cylindrical work having holes to be machined formed in the longitudinal direction, and the work holding means. A workpiece rotating means for rotating the workpiece together with the workpiece around the hole to be processed, a rod-shaped polishing member to be inserted into the hole to be processed, polishing member supporting means for rotatably supporting the polishing member, and support for the polishing member. The polishing member includes a polishing member urging means for urging the polishing member together with the polishing member toward the inner peripheral surface of the hole to be processed, and a polishing member rotating means connected to the polishing member and drivingly rotating the polishing member. ..

The hole inner surface polishing apparatus according to the second aspect of the present invention is, in addition to the above-mentioned configuration of the first aspect of the present invention, the work holding means and the work rotating means, the polishing member and the polishing member supporting means, and The polishing member urging means and the polishing member rotating means are provided with a work swinging means for relatively reciprocating along the longitudinal direction of the hole to be processed.

As the polishing member, it is possible to employ a metal round bar member around which a strip-shaped polishing cloth having abrasive grains fixed is wound. Further, a spring force, a weight, or the like may be used as the urging force of the polishing member urging means. Furthermore, in order to realize stable rotation of the polishing member, it is effective to support both ends of the polishing member by the polishing member supporting means.

It is also possible to further add abrasive grain supplying means for supplying loose abrasive grains between the outer peripheral surface of the polishing member and the inner peripheral surface of the hole to be processed. In this case, the longitudinal direction of the work may be oriented vertically and the loose abrasive grains may be poured from above the hole to be processed.

[0015]

The work is held by the work holding means so that the center of the hole to be machined formed in the cylindrical work and the rotation center of the work rotating means are coaxial, and the work rotating means is operated to operate the work. Is rotated around the hole to be processed together with the work holding means. On the other hand, by operating the polishing member rotating means, the rod-shaped polishing member is driven and rotated to be inserted into the hole to be processed, and the polishing member supporting means for rotatably supporting the polishing member is provided on the inner peripheral surface of the hole to be processed together with the polishing member. By urging, the inner peripheral surface of the workpiece is smoothly polished by the polishing member.

In this case, since the center of rotation of the workpiece rotated by the workpiece rotating means coincides with the center of the hole to be machined, not only the workpiece in which the hole to be machined is formed coaxially with the workpiece but also the hole to be machined. The inner peripheral surface of the hole to be machined can be polished without any problem even for a workpiece in which the machined hole is formed in an eccentric state.

Further, in the second aspect of the present invention, since the work and the polishing member reciprocate relatively in the longitudinal direction of the hole to be processed by the work swinging means, the inner peripheral surface of the hole to be processed and the polishing member. The relative movement with respect to the outer peripheral surface of the workpiece becomes a combined movement in two directions, that is, the circumferential direction and the longitudinal direction of the hole to be machined, so that polishing can be performed uniformly in the longitudinal direction and the relative movement speed of these is further increased. The inner peripheral surface of the hole to be processed is polished even more smoothly.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the hole inner surface polishing apparatus according to the present invention is a round rod-shaped light in which two stress applying member charging holes for manufacturing an optical fiber for maintaining a polarization mode are formed adjacent to each other. As shown in FIG. 1 showing the appearance of one embodiment applied to a fiber preform, a processing table 12 is horizontally projected at the center of a vertically installed column 11. Further, a cylindrical chuck holder 13 that vertically penetrates the processing table 12 is attached to the processing table 12 so as to be rotatable around a vertical axis.

As shown in FIG. 1 and FIG. 2 showing the planar shape of the chuck holder 13, the chuck holder 13 is provided with the optical fiber preform 14 inserted into the chuck holder 13 with respect to the chuck holder 13. A plurality (three in the illustrated example) of chuck claws 15 that can be fixed in an arbitrary eccentric state are attached.
3 and the chuck claws 15 and the like constitute the work holding means of the present invention. These chuck claws 15 can be independently fixed at arbitrary positions in the radial direction of the chuck holder 13, and the preform 1 for the optical fiber is provided.
4 and the center of the hole 16 to be machined and the chuck holder 1
The center O of 3 can be set concentrically.

The spindle 18 of the holder drive motor 17 installed vertically downward on the column 11 has a drive pulley 1
9 is integrally fitted, and the endless drive belt 2 is attached to the drive pulley 19 and the outer peripheral surface of the chuck holder 13.
0 is wrapped around. That is, the holder drive motor 1
The chuck holder 13 is driven and rotated with respect to the processing table 12 via the drive belt 20 by operating the drive belt 7. The chuck holder 13, the holder drive motor 17, the drive pulley 19, the drive belt 20, etc. The work rotating means of the present invention is fixed.

At the upper end of the column 11 on which a pair of upper and lower evacuation guide rails 21 that extend horizontally are formed, a ram head 22 that can be moved left and right along the evacuation guide rails 21 at any sliding position. It is provided.
Further, the saddle 22 on which the vertically extending guide rail 23 for attachment and detachment is formed is provided with a ram 24 which can be moved up and down to an arbitrary sliding position along the guide rail 23 for attachment and detachment.

Further, the ram 24 is provided with a motor base 26 which can be moved back and forth in a horizontal direction at right angles to the moving direction of the ram head 22 via a fluid pressure actuator 25 such as an air cylinder. Two
5, the motor base 26 and the ram 24 are connected to each other through a pair of linear guide devices 27 in order to smoothly guide the forward and backward movement of the motor base 26. In the present embodiment, the motor base 26 and the ram 24 are connected to each other. A return spring 28 is interposed between the ram 24 and the ram 24.

A grindstone drive motor 29 installed downward on the motor base 26 and constituting the polishing member rotating means of the present invention.
Is a grindstone capable of gripping the upper end of a round bar-shaped grindstone 30 in which fine abrasive grains (not shown) are fixed to the outer peripheral surface and are inserted into the holes 16 to be processed of the optical fiber preform 14 in a penetrating state. The chuck 31 is integrally fitted, and by driving the grindstone drive motor 29, the rod grindstone 30 can be driven and rotated about a vertical axis.

In this embodiment, by supplying fluid pressure to the fluid pressure actuator 25, the rotation center of the grindstone chuck 31 and the rotation center O of the chuck holder 13 are set to be concentric. By discharging the fluid pressure from the fluid pressure actuator 25, the spring force of the return spring 28 acts to cause the motor base 26 to move to the ram 24.
It is designed to be biased to the side.

On the other hand, the fixed ram 32 installed at the lower end of the column 11 has a chuck base which can be moved back and forth in parallel with the motor base 26 via a fluid pressure actuator 33 having the same structure as the fluid pressure actuator 25. 34
Is provided for smoothly guiding the back and forth movement of the chuck base 34 by the fluid pressure actuator 33,
The chuck base 34 and the fixed ram 32 are connected to each other via a pair of linear guides 35. In the present embodiment, a return spring 36 is interposed between the chuck base 34 and the fixed ram 32. ing.

The fluid pressure actuator 33, the chuck base 34, the linear guide device 35, and the return spring 36 are the same as the fluid pressure actuator 25 and the motor base 2 described above.
6, the linear guide device 27 and the return spring 28 have exactly the same functions, and these constitute the polishing member urging means of the present invention. That is, by supplying the fluid pressure to the fluid pressure actuator 33, the rotation center of the grindstone chuck 37 and the rotation center O of the chuck holder 13 are set to be concentric. Is discharged, the spring force of the return spring 36 acts to bias the chuck base 34 toward the fixed ram 32.

The chuck base 34 has a rod grindstone 30.
A grindstone chuck 37 capable of holding the lower end of the grindstone chuck 37 is rotatably provided via a chuck holder 38, and a pair of upper and lower grindstone chucks 31 and 37 constituting the polishing member supporting means of the present invention together with the chuck holder 38. ,
Both ends of the rod grindstone 30 are held in a stable state.

As described above, in this embodiment, the upper and lower end portions of the rod grindstone 30 are held by the grindstone chucks 31 and 37, but the rod grindstone 30 and the grindstone drive motor 29 which is the polishing member rotating means are connected. Upper grindstone chuck 3
When the rigidity of No. 1 is sufficiently high, the pressing force of the rod grindstone 30 can be maintained substantially even above and below the hole 16 to be processed in the optical fiber preform 14, so that the lower grindstone chuck 3
There is no problem even if the fixed ram 32, the fluid pressure actuator 33, the chuck base 34, the linear guide device 35, the return spring 36, and the chuck holder 38 are omitted, including 7.

As shown in FIG. 1 and FIG. 3 showing the concept of the working fluid supply system in this embodiment, the hole 16 and the rod grindstone 30 are provided directly above the hole 16 to be processed in the optical fiber preform 14. An upper end portion of a machining liquid supply pipe 40 for supplying the machining liquid 39 containing free abrasive grains is fixed to the gap of the above through a bracket (not shown). Machining liquid supply pump 4 on the way
The lower end of the machining fluid supply pipe 40 in which 1 is interposed is fixed in a machining fluid reservoir 42 provided below the lower grindstone chuck 37, and the machining fluid 39 stored in the machining fluid reservoir 42 is fixed. When the machining liquid supply pump 41 is operated, the hole 1 to be machined in the optical fiber preform 14 is processed through the machining liquid supply pipe 40.
It is supplied to the gap between the hole 16 and the rod grindstone 30 from the upper side of 6.

Further, in this embodiment, the stirring blade 44 connected to the stirring drive motor 43 is arranged in the processing liquid reservoir 42 for collecting the processing liquid 39 which flows down from the gap between the hole 16 to be processed and the rod grindstone 30. As a result, the working fluid 39 in the working fluid reservoir 42 is uniformly stirred.

In the actual work, first, the ram head 2
2 is retracted to either the right or left of the column 11 along the retracting guide rail 21, the optical fiber preform 14 is then passed through the chuck holder 13, and the chuck claws 15 are respectively operated to move the optical fiber as shown in FIG. The center of the hole 16 to be machined in the base material 14 and the center O of the chuck holder 13 are aligned. Then, after the rod grindstone 30 is passed through the hole 16 to be processed and the lower end thereof is held by the grindstone chuck 37 on the lower side,
The ram head 22 is returned to the processing position shown in FIG. 1 so that the ram head 22 is located above the fixed ram 32. Further, the ram 24 located at the rising end of the ram head 22 is lowered, and the upper end of the rod grindstone 30 is gripped by the upper grindstone chuck 31.

Up to this point, the fluid pressure actuator 25,
Since fluid pressure is supplied to each of 33, the rod grindstone 3
0 is also held concentrically with the hole 16 to be machined in the optical fiber preform 14, and from this state the holder drive motor 17
And the grindstone drive motor 29 to drive the optical fiber preform 1
4 is driven and rotated at a low speed together with the chuck holder 13, while the rod grindstone 30 is driven and rotated at a high speed in a direction opposite to the rotational direction thereof.

The fluid pressure actuators 25, 33
It is driven together with the chuck holder 13 by releasing the fluid pressure from the motor and urging the motor base 26 toward the ram 24 side and the chuck base 34 toward the fixed ram 32 side by utilizing the spring force of the return springs 28 and 36. The outer peripheral surface of the rod grindstone 30 that is driven and rotated in the opposite direction is pressed against the inner peripheral surface of the hole 16 to be machined in the rotating optical fiber preform 14.
At the same time, the machining fluid supply pump 41 is driven, and the machining fluid 39, which is uniformly agitated by the agitation blade 44 by the operation of the agitation drive motor 43, is formed between the hole 16 and the whetstone 30 to be machined. By supplying, the entire inner peripheral surface of the hole 16 is sequentially and smoothly polished smoothly.

When the machining of the inner peripheral surface of the hole 16 is completed, the fluid pressure is supplied to the fluid pressure actuators 25 and 33 to resist the spring force of the return springs 28 and 36 and the motor base 26 and the chuck base 34. Back to the original standby position, hold the rod grindstone 30 concentrically with the hole 16, and stop the operation of the holder drive motor 17 and the grindstone drive motor 29.
Further, the operation of the machining liquid supply pump 41 is stopped. Then, the upper grindstone chuck 31 is operated to release the grip of the grindstone chuck 31 from the rod grindstone 30, and the ram 24 is pulled up to the rising end of the ram head 22.
Is moved to the left or right of the column 11. And
The lower grindstone chuck 38 is operated to release the grip of the grindstone chuck 38 from the rod grindstone 30, and the rod grindstone 30 is inserted into the hole 16
The optical fiber preform 14 is detached from the chuck holder 13 by pulling out from the chuck holder 13 and operating the chuck claw 15 further.

Thus, in this embodiment, the ram head 22 is used.
Is retracted to the side of the column 11 and the rod grindstone 30 is pulled out upward.
When 4 can be set to be sufficiently long, it is possible to omit the evacuation guide rail 21 and the ram head 22 and form the attachment / detachment guide rail 23 directly on the column 11. Further, the vertical relationship of the ram head 22 and the fixed ram 32 provided on the column 11 may be set upside down so that the rod grindstone 30 is pulled out downward.

Further, in the present embodiment, the processing pressure of the rod grindstone 30 against the inner peripheral surface of the hole 16 is obtained by the spring force of the return springs 28 and 36, but magnetic force, rubber-like elastic body, vacuum suction force or the like is used. It is also possible to generate the processing pressure by making the fluid pressure actuators 25 and 33 double acting and omitting the return springs 28 and 36.
A constant processing pressure may be obtained by 33.

Further, it is possible to secure the processing pressure of the rod grindstone 30 by using a weight in place of the return springs 28 and 36, and such a hole inner surface polishing apparatus according to the present invention as shown in FIG.
When applied to the embodiment shown in FIG.
As shown in FIG. 4 showing the appearance of the extracted portion, a fixed ram 32 for holding a chuck base 34 provided with a grindstone chuck 38 via a pair of fluid pressure actuators 33.
A pulley 46 is rotatably attached to the bracket via a bracket 45. A cable 48 wound around this pulley 46 and having a weight 47 attached to the lower end.
Is connected to the chuck base 34, and this structure is exactly the same for the upper motor base 26.

Therefore, when the fluid pressure is released from the fluid pressure actuator 33, the chuck base 34 is attracted to the fixed ram 32 side by the weight of the weight 47. As a result, the rod grindstone 30 gripped by the grindstone chuck 38 is not shown in the optical fiber. Urged by the inner peripheral surface of the hole 16 to be machined in the base material 14,
A processing pressure corresponding to the weight of the weight 47 can be generated.

For the optical fiber preform 14 in which the holes 16 to be processed are formed concentrically, the optical fiber preform 14 is simply held concentrically with respect to the center O of the chuck holder 13. It suffices to do so. In this case, a chuck of a scroll type or the like in which all the chuck claws 15 move in conjunction with each other can be adopted.

FIG. 5 is an external view of another embodiment of the hole inner surface polishing apparatus according to the present invention using a scroll type chuck having such an aligning function, and FIG. 6 is an external view of the chuck holder portion thereof. And, as shown in FIG. 7 showing the planar shape thereof, at the upper end of the cylindrical chuck holder 13 in which the drive belt 20 is wound around the outer peripheral surface of the lower end,
A slide base 49 having a rectangular plate shape is integrally fixed. A slider 51 having a scroll chuck 50 for holding the optical fiber preform 14 is mounted on the slide base 49 so as to be horizontally slidable in the horizontal direction in FIG. A spindle head 54 of a micrometer 53 attached to one end of a slide base 49 is connected via 52. Other configurations may be the same as those of the previous embodiment shown in FIG. 1, and the members having the same functions as those of the previous embodiment shown in FIG. Is marked.

Therefore, the optical fiber preform 14 is gripped by the scroll chuck 50 so that the eccentric direction of the hole 16 to be machined in the optical fiber preform 14 and the sliding direction of the slider 51 coincide with each other, then By moving the slider 51 with respect to the slide base 49 by operating the micrometer 53 by an amount corresponding to the eccentric amount of the hole 16 to be machined with respect to the center of the optical fiber preform 14, the center O of the chuck holder 13 is moved. On the other hand, the hole 16 to be processed in the optical fiber preform 14 can be positioned concentrically.

In this case, it is also possible to interpose a second slide base between the slide base 49 and the slider 51 so that the slider 51 can slide horizontally also in the vertical direction in the figure. Also, instead of the chuck claw 15, V
A pair of blocks each having a groove shape formed on at least one side are assembled to the chuck holder 13 to form the optical fiber preform 1
4 may be grasped.

The external appearance of another embodiment of the hole inner surface polishing apparatus according to the present invention which employs such a work holding means is shown in FIGS. 8 and 9, respectively. In the embodiment shown in FIG. 8, a chevron-shaped holding block 55 for holding the optical fiber preform 14 is mounted on a slider 51 which is horizontally slidably attached to a slide base integrated with the chuck holder 13 by bolts or the like. The holding block 55 and the mountain-shaped holding block 57 corresponding to the holding block 55 are connected to each other by fastening fittings 58 such as bolts, and the pair of holding blocks 55, 57 holds the optical fiber preform 14. Further, in the embodiment shown in FIG. 9, a flat plate 59 is used in place of the chevron-shaped holding block 57 in the embodiment of FIG. 8, and the flat plate 59 and the holding block 55 hold the optical fiber preform 14. It is a thing. The rest of the configuration may be the same as that of the previous embodiment shown in FIG. 5, and the members having the same functions as those of the previous embodiment shown in FIG. Is marked.

In the hole inner surface polishing apparatus according to the second aspect of the present invention, the workpiece holding means and the workpiece rotating means, the polishing member, the polishing member supporting means, the polishing member biasing means and the polishing member rotating means are processed holes. Of the second embodiment of the present invention in which the work swinging means for relatively reciprocating along the longitudinal direction of the workpiece is incorporated into the embodiment shown in FIG. Is shown in FIG. That is, in the central portion of the vertically installed column 11, a base end portion of the processing table 12 which horizontally projects from the column 11 is held so as to be able to move up and down. A table rocking means 60 is interposed between the processing table 12 and the column 11, and by driving the table rocking means 60,
The processing table 12 swings up and down with respect to the column 11.

Therefore, when the holder driving motor 17 and the grindstone driving motor 29 are operated to machine the inner peripheral surface of the hole 16 to be machined in the optical fiber preform 14, the table swinging means 6 is used.
By operating 0 to combine the raising and lowering operations of the processing table 12, the directionality of the scratches of the abrasive grains generated on the inner peripheral surface of the hole 16 to be processed is canceled, and as a result, The smoothness of the peripheral surface is further improved. Otherwise, the configuration may be exactly the same as that of the embodiment described above with reference to FIG. 1, and the reference numerals in FIG. 10 denote the same functions as those of the previous embodiment shown in FIG. Is written.

In these examples, the case of polishing the inner peripheral surface of the hole for inserting the stress applying member formed in the optical fiber preform has been described, but it is formed of another hard and brittle material. Of course, it can also be applied to the inner surface polishing of holes,
Although the optical fiber preform 14 is held vertically,
It may be held in an inclined state or may be held horizontally. Further, it is of course possible to appropriately combine the above-mentioned plurality of embodiments and to adopt another configuration.

[0047]

According to the hole inner surface polishing apparatus of the present invention, the inner surface of the hole formed in an eccentric state with respect to the cylindrical member can be efficiently and smoothly ground, so that the core portion is formed inside the hole. When a rod-shaped glass is inserted, and these are integrated by heating to manufacture an optical fiber for maintaining the polarization mode, there is no problem that bubbles remain at the interface and adversely affect the characteristics of the optical fiber. An optical fiber for maintaining the polarization mode can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of an embodiment of a hole inner surface polishing apparatus according to the first present invention.

FIG. 2 is a plan view of a portion of a chuck holder in this embodiment.

FIG. 3 is a conceptual diagram of a working liquid supply system in the present embodiment.

FIG. 4 is a perspective view showing an external appearance of a portion of a grindstone chuck in another embodiment of the hole inner surface polishing apparatus according to the present invention for generating a processing pressure on a rod grindstone.

FIG. 5 is a perspective view showing the outer appearance of another embodiment of the hole inner surface polishing apparatus according to the present invention for holding the optical fiber preform in an eccentric state.

FIG. 6 is a front view of an appearance in which a chuck portion is extracted.

FIG. 7 is a plan view thereof.

FIG. 8 is a perspective view showing the appearance of another embodiment of the hole inner surface polishing apparatus according to the present invention for holding the optical fiber preform in an eccentric state.

FIG. 9 is a perspective view showing the appearance of yet another embodiment of the hole inner surface polishing apparatus according to the present invention for holding the optical fiber preform in an eccentric state.

FIG. 10 is a perspective view showing an appearance of an embodiment of a hole inner surface polishing apparatus according to the second invention.

FIG. 11 is a side view showing the appearance of a conventional hole inner peripheral surface polishing apparatus.

12 is a sectional view taken along the line XII-XII in FIG.

[Explanation of symbols]

11 is a column, 12 is a processing table, 13 is a chuck holder, 14 is an optical fiber preform, 15 is a chuck claw, and 1
6 is a hole, 17 is a holder drive motor, 18 is a spindle,
Reference numeral 19 is a drive pulley, 20 is a drive belt, 21 is a retracting guide rail, 22 is a ram head, 23 is a detachable guide rail, 24 is a ram, 25 is a fluid pressure actuator, 26 is a motor base, 27 is a linear guide device, 28 Is a return spring,
29 is a grindstone driving motor, 30 is a rod grindstone, 31 is a grindstone chuck, 32 is a fixed ram, 33 is a fluid pressure actuator,
34 is a chuck base, 35 is a linear guide device, 36 is a return spring, 37 is a grindstone chuck, 38 is a chuck holder,
39 is a working fluid, 40 is a working fluid supply pipe, 41 is a working fluid supply pump, 42 is a working fluid reservoir, 43 is a drive motor for stirring,
44 is a stirring blade, 45 is a bracket, 46 is a pulley, 4
7 is a weight, 48 is a cable, 49 is a slide base, 5
0 is a scroll chuck, 51 is a slider, 52 is a bracket, 53 is a micrometer, 54 is a spindle head, 55 is a holding block, 56 is a fastening bracket, 57 is a holding block, 58 is a fastening bracket, 59 is a flat plate, and 60 is a table. The swinging means, O, is the center of the chuck holder.

Claims (5)

[Claims] 1. A work holding means for holding a cylindrical work having holes to be machined formed in the longitudinal direction, and a work rotating means for rotating the work holding means together with the work around the hole to be machined. A rod-shaped polishing member to be inserted into the hole to be processed, a polishing member support means for rotatably supporting the polishing member, and the polishing member support means together with the polishing member for biasing the inner peripheral surface of the hole to be processed. And a polishing member rotating means that is connected to the polishing member and drives and rotates the polishing member. 2. A work holding means for holding a cylindrical work having holes to be machined formed in the longitudinal direction, and a work rotating means for rotating the work holding means together with the work around the hole to be machined. A rod-shaped polishing member to be inserted into the hole to be processed, a polishing member support means for rotatably supporting the polishing member, and the polishing member support means together with the polishing member for biasing the inner peripheral surface of the hole to be processed. Polishing member urging means, polishing member rotating means connected to the polishing member and drivingly rotating the polishing member, the work holding means and the work rotating means, the polishing member, the polishing member supporting means and the polishing member. A hole inner surface polishing apparatus comprising: a biasing means and a polishing member rotating means, and a work rocking means for relatively reciprocating along a longitudinal direction of the hole to be processed. 3. The abrasive grain supply means for supplying loose abrasive grains between the outer peripheral surface of the polishing member and the inner peripheral surface of the hole to be processed, as set forth in claim 1 or claim 2. Hole inner surface polishing device. 4. The hole inner surface polishing apparatus according to claim 1, wherein the polishing member supporting means rotatably supports both ends of the polishing member. 5. The hole inner surface polishing apparatus according to claim 1 or 2, wherein the hole to be processed is formed in an eccentric state with respect to the workpiece.