JPH0255190B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a precision grinding machine for grinding the outer peripheral surface of a component constituting, for example, an optical fiber connector.

(Prior Art) Connectors have traditionally been used as jigs for connecting optical fibers.

As shown in FIG. 8, this connector consists of a cylindrical adapter 100 and ferrules 101, 101 that are fitted into the adapter 100 from both sides.The ferrule 101 has a capillary 103 made of ceramic inside a metal collar 102 made of stainless steel or the like. Insert and attach optical fiber core wire 104
is inserted into the collar 102 and the core wire 104
The optical fiber strand 105 exposed by peeling off the jacket is inserted into the small diameter center hole 106 of the capillary 103, and by fitting the pair of ferrules 101, 101 into the adapter 100, the optical fiber strand 105 is inserted into the small diameter center hole 106 of the capillary 103. , 105 are butted against each other to optically connect them.

By the way, in the connector described above, the center holes 106, 10 of the left and right capillaries 103, 103
If 6 do not match, light transmission cannot be performed. In particular, the diameter of the optical fiber (core) is extremely small, 50 to 100 μm for multimode fiber and 50 to 10 μm for single mode fiber.
If even a slight positional shift occurs, it will interfere with the transmission of light.

In addition to the case where the center hole 106 is not formed at the center of the capillary 103, the cause of the positional deviation is that even if the center hole 106 is formed at the center of the capillary 103, the collar 1
This also occurs when the center of the outer peripheral surface of the collar 102, that is, the axis of the collar 102, and the center hole 106 do not match.

Therefore, the axis of the collar 102 and the capillary 10
A grinding process is required to match the center hole 106 of No. 3. As for this grinding method,
There is one disclosed in Publication No. 67714. In this method, as shown in FIG.
While rotating the ferrule 101 at step 9, the whetstone 110
The outer circumferential surface of the collar 102 is ground.

(Problems to be Solved by the Invention) In the conventional grinding method described above, both ends of the ferrule are centered by the conical centers 107 and 108, and the ferrule itself is small, especially if it is a conical center. The center hole 106 of the capillary 103 against which the tip of the shaped center 107 is pressed
Since the diameter is extremely small, workability is poor.

Furthermore, since the capillary 103 is made of ceramics, it has high hardness, and therefore the conical center 1
The tip of the 07 is severely worn and the center must be replaced frequently. Furthermore, since the tip of the center 107 is inserted into the center hole 106 of the capillary 103, the center hole 106 may be deformed or crushed.

There are many problems when grinding a ferrule while fixing it using a conical center in this way.

Therefore, the present invention enables an apparatus for grinding the outer circumferential surface of a workpiece such as a ferrule to grind the outer circumference of the workpiece so that it is concentric with the axis of the workpiece without using a conical center. The purpose of the present invention is to provide a precision grinding machine that is easy to install and capable of high-precision grinding.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a first movable table 8 that can reciprocate in the X-axis direction, and a second movable table 8 that can reciprocate by a specific distance in the Y-axis direction. The first moving table 8 has a spindle 13 for rotating the workpiece 12, chuck mechanisms 35, 37 for holding the workpiece 12, and the chuck mechanisms 35, 37 are arranged in the X-axis direction. a suction mechanism having a fine adjustment mechanism movable in orthogonal vertical planes and a suction plate 29 for suctioning the chuck mechanisms 35 and 37 to the spindle 13;
The moving table 10 includes a camera 49 for photographing the center of the work 12 on the monitor 52, and a camera 49 for photographing the center of the work 12 on the monitor 52.
A grindstone rotation spindle 52 for grinding the outer peripheral surface of the workpiece is provided, and a reference line 52a is provided on the monitor 52 to align the center hole of the workpiece photographed by the camera with the center of the workpiece and the rotation center of the spindle. It is characterized by

(Function) The workpiece is held by the chuck, the center of the workpiece is enlarged and displayed on the monitor via the camera, and the fine adjustment mechanism is used to align the center of the workpiece with the rotation center of the workpiece rotation spindle. After moving the chuck mechanism in a vertical plane, the chuck mechanism is suctioned and fixed to the spindle, and then the movable table to which the grindstone rotating spindle is fixed is moved to the grinding position to grind the outer periphery of the workpiece.

(Example) Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view of a precision grinding machine according to the present invention, and FIG. 2 is a front view of the same precision grinding machine. A surface plate 4 is placed on it.

On the stone surface plate 4 are a pair of first rails 5, 5 made of ceramics extending in the X-axis direction and a pair of second rails 6, 6 made of ceramics extending in the Y-axis direction.
A first moving platform 8 that moves in the X-axis direction by a first drive unit 7 using a pulse motor is engaged with the first rail 5, and a closed-loop control system is installed on the second rail 6. The second servo motor
A second movable table 10 that moves in the Y-axis direction by a drive unit 9 is engaged.

Note that the sliding portions of the first rail and the first moving table and the second rail and the second moving table adopt an air slide system, and since the movement is smooth with little wear, the positioning accuracy is improved.

A truing device 11 for adjusting the roughness of the grindstone to a constant level and a spindle 13 for rotating a ferrule 12 as a workpiece are fixed on the first movable table 8.

Here, the ferrule 12 may have the structure shown in FIG. 3, for example, in addition to the one shown in FIG. That is, the ferrule 12 shown in FIG. 3 has a conventional structure in which it is formed of a ceramic body 14 with a center hole 14a formed up to the portion that becomes the collar, and this ceramic body 14 is fitted into a metal body 16 having a flange portion 15. It's summery. With such a structure, the production of the ferrule can be simplified, and it can also have excellent wear resistance and precision.

On the other hand, the spindle 13 houses a rotating cylinder 18 in a ceramic case 17 as shown in FIG. Attach the drive rotating end plate 2 using the bolt 22 to 21.
3 and a driven rotating end plate 24 are fixed to each other, inner plates 23a and 24a of these rotating end plates 23 and 24 are made of ceramics, and outer plates 23b and 24b are made of metal such as stainless steel. Further, a minute gap 25 is formed between the case 17 and the rotary cylinder 18, and the case 17 includes a passage 26 for introducing air into this gap 25 and an opening 27 for supplying air to this passage 26.
is formed.

In order to drive the spindle 13, the rotation of a motor (not shown) is transmitted to the drive rotating end plate 23 via a belt.
7. Air is supplied to the gap 25 between the case 17 and the rotary cylinder 18 through the passage 26, and the rotary cylinder 18 is rotated in a floating supported state.

By rotating the rotary cylinder 18 in this floating supported state, rotational friction can be made extremely small. In addition, the spindle 13 used in this embodiment includes a case 17 and a rotating cylinder 18.
The rotary end plates 23, 24 and the inner plates 23a, 24a are both made of ceramics, making them lightweight and with little thermal expansion, making it possible to perform processing with extremely high roundness without shifting the rotational axis. Can be done.

Further, a suction plate 29 constituting a part of the suction mechanism is fixed to the outer plate 24b of the driven rotating end plate 24 by bolts 28, and a suction groove 30 is formed on one surface of this suction plate 29. 30 is a stone surface plate 4 via a suction pipe 31 penetrating the spindle 13.
It is connected to a vacuum device 32 provided above. A chuck mount 34 is held on the suction plate 29 with some play by a locking piece 33, and a hand chuck 35, which constitutes a part of the chuck mechanism, is attached to the chuck mount 34 with a bolt 36. There is. Then, by turning the hand chuck 35,
The chuck pieces 37 of the book contract and expand in diameter to attach and detach the ferrule 12. Furthermore, the chuck mount 34 can be adjusted in position in a vertical plane perpendicular to the X-axis by a fine adjustment mechanism. As shown in FIG. 5, which is a cross-sectional view taken along line A-A in FIG. small diameter holes 39, 39 are formed at positions opposite to these rectangular holes 38, 38.
The small diameter hole 39 is sealed with a screw plug 40, and a spring 41 is provided in the small diameter hole 39, and the resilient force of the spring 41 brings the receiving piece 42 into contact with the side surface of the chuck mounting base 34. ing.
Further, the large diameter rectangular hole 38 is sealed with a plug member 43, and a plug member 4 is provided inside the plug member 43.
Slide member 44 whose surface facing 3 is a tapered surface
are slidably provided, and a wedge 45 faces between the plug member 43 and the slide member 44.
This wedge 45 is fixed to the tip of a fine adjustment handle 46 that spirals in a direction perpendicular to the axial direction of the rectangular hole 38, and the wedge 45 and a screw plug 47 provided on the opposite side of the fine adjustment handle 46 are connected to each other. A spring 48 for preventing rattling is installed between the two.

In the above, when the fine adjustment handle 46 is rotated and screwed forward, the wedge 45 moves in the direction of the arrow in the figure, and since the wedge 45 and the slide member 44 are in contact with each other even on their tapered surfaces, the wedge 45
With this movement, the slide member 44 moves in the axial direction of the rectangular hole 38, and the movement of the slide member 44 adjusts the position of the chuck mount 34 in a vertical plane perpendicular to the X-axis.

On the other hand, on the second movable table 10, a reflective ultra-small television camera 49 and a spindle 51 for rotating a grindstone 50 are fixed at a predetermined distance in the Y-axis direction, and the television camera 49 is mounted on a stone surface plate. 4 is connected to a television monitor 52 provided on the top of the screen.
Here, the fixed position of the television camera 49 is fixed at a position that completely coincides with the center of rotation of the spindle 13 when the second movable table 10 is at the reference position, that is, the position shown in FIG.

Furthermore, on the side of the stone surface plate 4, a grinding fluid filtration device 53 is installed.
An air cleaner unit 54 and a control panel 55 are arranged.

A grinding method using a grinding machine having the above configuration will be explained below.

First, with the second movable base 10 stopped at the reference position, the first movable base 8 is moved back to the right in the figure by the operation of the first drive unit 7. After retracting the first moving table, the chuck pieces 37 are enlarged in diameter by rotating the hand chuck 35, and the chuck pieces 37 are expanded in diameter.
Insert the rear end of the ferrule 12 between the chucks 37 and 7, turn the hand chuck 35 to the opposite side again to reduce the diameter of the chuck pieces 37, and hold the ferrule 12 by the chuck pieces 37.

Once the ferrule 12 is held by the chuck pieces 37, the movable table 8 is moved by the operation of the first drive section 7.
The ferrule 12 is moved forward to the left in the figure and stopped at the reference position, and then the center hole 14a of the ferrule 12 is displayed on the screen of the television monitor 52 through the television camera 49 at a magnification of approximately 1000 times as shown in FIG. Here, in addition to the center hole 14a, four reference lines 52a... are displayed on the screen, and these reference lines 52a...
If the image of the center hole 14a is accurately placed within the rectangle surrounded by a, it means that the center hole 14a and the rotation center of the spindle 13 are aligned. However, if the image of the center hole 14a is misaligned as shown in the figure, operate the fine adjustment handle 46 to slightly move the chuck mount 34 vertically and horizontally.
The image of the center hole 14a is accurately placed within a rectangle on the screen of the television monitor 52, and the center of rotation of the spindle 13 and the center hole 14a of the ferrule 12 are aligned.
make them completely consistent.

When the center hole 14a of the ferrule 12 and the center of rotation of the spindle 13 coincide, the vacuum device 32 is driven to suction and fix the chuck mount 34 to the suction plate 29, and the second drive unit 9 is activated. The second moving table 10 is moved along the rail 6, the grindstone 50 is moved to the grinding position set in the program, and the ferrule 12 is rotated by the spindle 13.
The grindstone 50 is rotated by the ferrule 12.
Grind the outer peripheral surface of. Note that even if the diameter of the grindstone 50 changes, the cutting position can be set arbitrarily by a program.

Next, when the position of the second movable table 10 reaches the grinding end position, the first movable table 8 is made to move forward and backward repeatedly to perform traverse grinding, and when this traverse grinding is completed, the first movement is started. The table 8 is moved slightly backward, the second moving table 10 is returned to the reference position (centering position), the first moving table is then advanced to the reference position, and the ferrule 1 is moved back again.
The central hole 14a of No. 2 is displayed on the television monitor 52 to confirm whether or not the ferrule 12 was not misaligned during grinding.

Next, the first movable base 8 is moved backward, the chuck mounting base 34 is released from the suction state, and the hand chuck 3 is
5, loosen the chuck piece 37, and eject the ferrule 12. At this time, if there is a misalignment during grinding, it will be lined out. This can reduce the load on the inspection process, which is a post-process.

If the case where the outer peripheral surface of the ferrule is ground using the grinding machine according to the present invention is shown with specific numerical values,
As shown in FIGS. 7A, B, C, and D, the average amount of eccentricity is 0.4 μm (maximum 1.5 μm), and the variation in the outer diameter of the ferrule is +0.5 μm and −1.0 μm.
Furthermore, the roundness is 0.2 μm or less, and the surface roughness is 0.07 μm.
It was mRa.

Although a ferrule is shown as a workpiece in the embodiment, it goes without saying that the grinding machine according to the present invention can also be applied to grinding the outer periphery of other parts.

(Effects of the Invention) As explained above, the grinding machine according to the present invention exhibits the following effects.

The fine adjustment mechanism that allows the chuck mechanism to move in a vertical plane perpendicular to the X-axis direction allows the rotation center of the spindle and the axis of the workpiece to be aligned quickly and accurately.

The suction mechanism allows fine adjustment work to be done with the chuck mechanism used to hold the workpiece released from the fixed state, making fine adjustment work easy, and the chuck mechanism can be fixed and released using a switch, etc. Since it can be performed with a simple operation, the work of fixing and releasing the chuck mechanism can be done easily and quickly.

The monitor allows you to see an enlarged view of the alignment between the rotation center of the spindle and the axis of the workpiece, so alignment can be done with high precision and changes in the diameter of the workpiece can be responded to immediately.

Since the conical center is not used when centering the workpiece, the workpiece installation work is simple and accurate, and there is no need to replace the center.

Since the center does not touch the center hole of the workpiece, the center hole will not be deformed or chipped.

The spindle that rotates the workpiece is equipped with a chuck mechanism that holds the workpiece, a fine adjustment mechanism that moves the chuck mechanism in a vertical plane, and a suction mechanism that fixes the chuck mechanism to the spindle side, making centering quick and easy. Furthermore, the dimensional accuracy is stable and the yield is greatly improved.

[Brief explanation of drawings]

Fig. 1 is a plan view of a grinding machine according to the present invention, Fig. 2 is a front view of the grinding machine, Fig. 3 is a cross-sectional view of a ferrule as a workpiece, Fig. 4 is a partial cross-sectional view of a spindle, Figure 5 is a sectional view taken along line A-A in Figure 4, and Figure 6
The figure is a diagram showing the screen of a television monitor, and FIGS. 7A to D are graphs showing variations in eccentricity and outer diameter.
Figure 8 is a cross-sectional view of the optical fiber connector, Figure 9
The figure is a perspective view showing a conventional grinding method. In addition, in the drawing, 4 is a stone surface plate, 5 is the first rail, and 6
is the second rail, 8 is the first moving platform, and 10 is the second rail.
moving table, 12 is a ferrule which is a workpiece, 1
3, 51 is the spindle, 14a is the center hole of the ferrule, 17 is the spindle case, 18 is the rotating cylinder,
29 is a suction plate, 30 is a suction groove, 34 is a chuck mounting base, 37 is a chuck piece, 45 is a wedge, 46 is a micro handle, 49 is a camera, 50 is a grindstone,
52 is a monitor.

Claims (1)

[Claims] 1. A first moving table 8 capable of reciprocating in the X-axis direction
and a second part that can reciprocate by a specific distance in the Y-axis direction.
The first moving table 8 includes a spindle 13 for rotating the workpiece 12, chuck mechanisms 35, 37 for holding the workpiece 12, and a chuck mechanism 35, 37 for holding the workpiece 12.
37 in a vertical plane perpendicular to the X-axis direction, and a suction mechanism having a suction plate 29 for suctioning the chuck mechanisms 35 and 37 to the spindle 13, The moving table 10 includes a camera 49 for photographing the center of the workpiece 12 on a monitor 52;
A grindstone rotation spindle 51 for grinding the outer peripheral surface of the workpiece 12 is provided, and a reference line 52a is provided on the monitor 52 to match the center hole of the workpiece photographed by the camera with the center of the workpiece and the rotation center of the spindle. A precision grinding machine that is characterized by: