JPS60177866A - Polishing of inner hole - Google Patents

Abstract

PURPOSE:To improve efficiency and prolong the life of a wire by nipping the wire by an elastic body and maintaining smoothness by continuously polishing the surface of the wire and finishing the inner-hole surface of a workpiece to high accuracy. CONSTITUTION:A carriage 4 is moved in reciprocation by a cylinder 5, and a wire 20 is brought into contact in slidable ways onto the inner-hole surface of a worked cylindrical body in a chuck 10, revolving the cylindrical body by a motor 17, and the inner surface is ground by lapping agent coated onto the wire 20. In this case, the wire 20 is pulled with a proper tension by cylinders 24 and 24. The wire 20 has a gentle tapered form which can be obtained by gradually reducing the diameter in the nearly half part of a piano wire having an outside diameter in accordance with the finished diameter of the inner hole of the cylindrical body through chemical errosion. A proper amount of lapping agent is supplied dropwise onto the superposed surface of an elastic body 28 from a feeding tank during grinding reciprocation movement, and the lapping agent is rubbing- applied onto the surface of the wire 20 through the elastic body 28 and removes the roughness of the wire surface, and the smoothness of the surface can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently polishing the inner surface of a cylindrical workpiece by wire lapping.

For example, a ferrule, which is a main component of an optical fiber cable connector, is made of a new ceramic material and is formed into a cylindrical shape.For example, the outer diameter is 1.8 mm, the inner hole diameter is 125 μm, and the circularity is 1 μm. The following is required. Wire lapping has conventionally been used to polish and finish inner holes that require such precision. This involves drilling a through-hole in the workpiece, passing a wire like piano wire through the hole, and applying a lapping agent made by mixing fine diamond abrasive grains of 1 to 2 μm in size with a suitable oil. The inner hole surface is ground by coating the wire and moving the wire back and forth. However, with this conventional wire wrapping method, the surface of the wire becomes rough in a short period of time, resulting in a loss of smoothness. For this reason, the polishing process takes a long time and reduces polishing efficiency, and at the same time, the accuracy required for the workpiece cannot be obtained.The life of the wire is also short, and the wire must be replaced frequently. There was a drawback.

The present invention has been made in view of these conventional drawbacks.
The surface smoothness of the wire is maintained even during wire lapping, thereby achieving polishing accuracy of the inner hole surface of the workpiece, reducing the polishing time, improving processing efficiency, and increasing the lifespan of the wire. The aim is to extend the period. To achieve this objective, the inner hole polishing method of the present invention involves passing a wire through the inner hole of a cylindrical workpiece, applying a lapping agent to the surface of the wire, and moving the wire in the axial direction of the workpiece. In the method of polishing the inner hole surface by moving the wire forward and backward, the wire is sandwiched between elastic bodies such as rubber, and the workpiece is polished while smoothing the peripheral surface of the wire with the wrapping agent. It is.

An embodiment of the present invention will be described below with reference to the drawings.

First, the internal hole polishing machine used in the present invention will be explained according to FIGS. 1 to 5. A table 2 is placed at the center of a rectangular fence-like frame 1, and a rail 3 is fixedly attached to the table along the longitudinal direction. do. Reference numeral 4 denotes a reciprocating carriage slidably disposed on the rail, and numeral 5 denotes a cylinder whose base end is fixed to an inner corner of the frame 1 in order to reciprocate the reciprocating carriage 4 along the rail 3. An operating rod 6 of the cylinder 5 is fixed to one side of the carriage 4 via a connecting piece 7. A pair of bearing arms 8, 8, which stand up from one side of the table 2, are bent so that their upper ends are located approximately above the center line of the carriage 4, and the cylindrical bearing arms 8, 8 are provided with bearings 9, 9 therebetween. A chuck 10 having a shape is rotatably provided. A cylindrical magazine 12 is housed in the chuck 10 and stores a plurality of cylindrical bodies 11 as workpieces in series. 13 is the magazine 12
A screw screwed into one end of the chuck 10 to prevent movement of the
Reference numeral 14 denotes a nut screwed onto the outer periphery of the lower end of the chuck 10 so that the chuck 10 can be detached from the bearings 9.

The chuck 10 is positioned between the bearing arms 8, 8.
A pulley 15 is fixed to the outer periphery of the pulley 15 with screws 16. , 17 is a motor fixedly installed in the frame 1, and a belt 19 is wound between a pulley 18 provided on the rotating shaft of the motor and the pulley 15, so that the chuck lO is rotated by the drive of the motor 17. ing. 20 is a tapered wire passed through the inner hole of the cylinder 11;
Approximately half of the length of the piano wire, which has an outer diameter (125 μm) that matches the finished diameter of the inner hole, is chemically etched to gradually become smaller in diameter (the outer diameter of the narrower part is 100 μm), resulting in a gentle taper. It is formed in the shape of. Stands 21.21 are erected at both ends of the carriage 4, and a movable body 22.22 is slidable on the stand 21.21 via a linear bearing in a direction parallel to the reciprocating direction of the carriage 4. Set it up so that The movable unit 22.22 is provided with heirs 23.23 for winding both ends of the wire 20, and cylinders 24.24 are provided on the back surface of the movable unit 22.22.
24 operating rods 25.25 are fixed to the back of the stand 21.21, respectively. Then, compressed air is sent to the cylinder and the operating rod 25. By protruding the wire 25, the wire 20 can be pulled with an appropriate tension. Reference numeral 26 denotes a support arm that stands upright next to the bearing arms 8, 8 on one side of the table 2, and the support arm is bent toward the carriage 4 side in the same way as the bearing arms 8. As shown in FIG.
An elastic body 28 (synthetic rubber) is bent into a U-shape and inserted therein, and the wire 20 is placed in a notch 29 on the opposite wall of the box body 27.
The elastic body 28 is configured to pass between the overlapping surfaces of the elastic body 28 through the elastic body 28. 30.30 indicates a bolt screwed into the side wall of the box body 27 in order to adjust the amount of bending of the elastic body 28. 31 is a funnel-shaped supply tank placed on the box body 27, and a diamond is placed inside the supply tank.

A lapping agent made by mixing abrasive grains such as SiC in kerosene is stored, and the lapping agent is dropped onto the overlapping surface of the elastic body 28 from the lower end of the supply tank, and the lapping agent is transmitted between the overlapping surfaces to the wire 20. so that it is applied to the surface of the Reference numeral 32 indicates an air supply pipe through which compressed air is blown into the supply tank 31 in order to appropriately stir the wrapping agent. Note that 33.33 indicates a limit switch that detects the moving end of the carriage 4.

However, in this inner hole polishing machine, the motor 17
While rotating, the cylinder 5 is operated to reciprocate the carriage 4, the wire 20 is brought into sliding contact with the inner hole surface of the cylindrical body 11, and the inner hole surface is ground by the lapping agent applied to the wire 20. At this time, the cylinder 24.24 pulls the wire 20 with an appropriate tension, but when the wire 20 gets caught in the inner hole of the cylinder 11, the air pressure inside the cylinder 24.24 suddenly changes. The structure is such that when a catch is detected, the cylinder 5 is switched in response to the signal, and the carriage 4 is moved in the opposite direction, and by repeating such reciprocating movement, the inner hole is moved to a predetermined position corresponding to the large diameter part of the wire 20. It can be ground to an inner diameter of . During this time, an appropriate amount of rewrap agent is dropped from the supply tank 31 between the overlapping surfaces of the elastic body 28, and this rewrap agent is rubbed against the surface of the wire 20 through the elastic body 28, so that the wire 20 is moved back and forth between the elastic bodies 28 and 28. By sliding with the wire 28, the surface of the wire 20 is ground to eliminate roughness. Note that it is desirable that the elastic body 28 be placed as close to the workpiece as possible.

As an example, a cylindrical body made of ceramic material mainly composed of A1203 was coated with a lapping agent containing diamond grains of 1 to 2 μm in diameter, and the wire was ground by reciprocating it 30 times per minute. When it was not clamped with elastic bodies, it took 34 minutes to finish the inner hole of the cylinder to the specified diameter, but when it was clamped with elastic bodies as in the method of the present invention, it took only 7 minutes. We were able to achieve the same finish as this, and the processing time required for polishing was significantly reduced. The reason why such good results were obtained is that when the wire is not sandwiched between elastic bodies, the surface of the wire becomes progressively rougher and loses its smoothness as the inner hole is repeatedly ground. This is believed to be because, in the method of the invention, the surface of the wire is constantly polished by an elastic body during grinding, so that the smoothness of the surface of the wire is maintained and effective contact between the surface of the wire and the bore in the cylinder is achieved.

FIG. 6 shows another embodiment of the structure in which the wire 20 is sandwiched between elastic bodies, in which two upper and lower flat plates 34 and 35 are used.
Elastic bodies 36 and 36 are pasted on the opposing surfaces of the elastic bodies 3 and 36, respectively.
6.36, the wire 20 is clamped. That is, one flat plate 34 is fixed horizontally on the support arm 40, screw punches 37.37 are firmly planted on both ends of the flat plate, and the screw punches 37.37 are loosely fitted into the other flat plate 35. , fit the coil spring 38.
9.39 are screwed together, and the flat plate 35 is pressed down by the elasticity of the coil spring 38. The wire 20 is pressed down by the elastic body 36.36.
Clamp with appropriate pressure. Even with this configuration, the wire 20 is polished with abrasive grains and the surface smoothness can be maintained as in the case of the above embodiment. It is more desirable to share the wires 20 with the right and left grips, as this allows the wire 20 to be clamped evenly over its entire circumferential surface.

As explained in the embodiments above, according to the polishing method of the present invention, the wire is sandwiched between elastic bodies and the surface of the wire is constantly polished to maintain smoothness, so that the inner hole surface of the workpiece is smoothed. Not only can it be finished with high precision, but the time required for machining can be significantly shortened and work efficiency can be significantly improved. It also has beneficial effects such as extending the life of the wire.

The method of the present invention can be applied to polishing various cylindrical workpieces, such as cemented carbide die tubes, in addition to the above-mentioned ceramic connectors for connecting optical fiber cables.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a plan view of an inner hole polishing machine, Fig. 2 is a cross-sectional view taken along line X-X in Fig. 1, and
Fig. 3 is a cross-sectional view taken along the line Y-Y in Fig. 1, Fig. 4 is an enlarged vertical sectional view showing the cylindrical set state, and Fig. 5 is an enlarged view of the mounting structure of the elastic body. FIG. 6 is an enlarged perspective view of another embodiment of the elastic body mounting structure. 4...Reciprocating stand, 5...Cylinder, 10...
Chatter, 11...Cylinder, 17...Motor, 2
0...Wire, 28...Elastic body. Patent applicant: Daido Steel Co., Ltd. Figure 3 Figure 4 Figure 5 Figure 2

Claims (1)

[Claims] In the method of polishing the inner hole surface by passing a wire through the inner hole of a cylindrical workpiece, applying a lapping agent to the surface of the wire, and moving the wire forward and backward in the axial direction of the workpiece. ,
An inner hole polishing method characterized in that a wire is sandwiched between elastic bodies such as rubber, and a workpiece is polished while smoothing the circumferential surface of the wire with the lapping agent.