JPH0310461B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a record mounting surface (hereinafter referred to as the first reference surface) of a turntable for a video disc.
This invention relates to a jig that enables cutting with high precision.

Conventionally, after forming a thin aluminum plate into a predetermined shape by press working, the first
The reference surface is cut with high precision to produce turntables for video discs.
In this case, the outer periphery of an aluminum plate or the like press-formed into a predetermined shape is chucked with a three-pronged chuck or the like.

Therefore, by chucking, external force distortion occurs in the aluminum plate, etc., and spring back occurs when the three-jaw chuck, etc. is removed, so that the specified accuracy (for example, as shown in Fig. 1, the diameter φ is
First reference plane 47 on a 260mm turntable
The flatness of is within 30μm, and the rotational surface runout is
It is required that it be within 50μm. ) is not available.

In the present invention, a plurality of pins that can be slid to follow the shape of the workpiece are provided concentrically below a plate made of aluminum or the like, and a cam is provided to fix the pins while each pin is in pressure contact with the back surface of the workpiece. Furthermore, by providing hollow suction pins with suction rubber integrally provided at their upper ends concentrically with each of the pins, it is possible to chuck thin workpieces without causing distortion due to external forces, thereby eliminating the above-mentioned drawbacks. This will be explained in detail below with reference to the accompanying drawings showing examples.

FIG. 3 is a central vertical sectional view of the jig of the present invention, FIG. 4 is a cross-sectional view taken from - in FIG. 3, and FIG. 5 is a partially enlarged sectional view of FIG. It consists of a vacuum chuck device.

The positioning device is the table set plate 1
A clamping plate 9 is provided below the (first plate) so as to be able to approach and separate from the table setting plate 1, and by bringing the clamping plate 9 close to the table setting plate 1, the pins 2, 3, 4
Retainer plate 19 and steel balls 10 for fixing
It is composed of. (The tightening plate 9 and the retainer plate 19 form a second plate.

The positioning pins 2, 3, and 4 are arranged in a relatively small concentric circle so that the positioning pins 3 are located directly under the annular groove 35 provided near the inner circumference of the turntable 33. , 4 are arranged in a relatively large concentric circle so as to be located directly below an annular groove 34 (FIG. 3) provided on the outer peripheral edge of the turntable.

Further, the positioning pins 4 are surface fixing pins provided at an interval of 120 degrees from each other,
Its base end is fixed to a chucking plate 26 provided so that the tightening plate 9 is positioned between it and the bottom surface of the table setting plate 1. The heads of the three positioning pins 4 form a reference surface for supporting the turntable.

Further, the pins 2 and 3 are provided with springs 11 and 3 between them and the chucking plate 26 and the tightening plate 9, respectively.
12, it is always urged in the direction of protruding from the table set plate 1.

The tightening plate 9 has a boss portion protruding from the center that penetrates the center portion of the table set plate 1, and a male thread is carved into the protruding outer end of the boss portion so that the nut 20 can be screwed into the tightening plate 9. .

Therefore, by operating the nut 20, the tightening plate 9 can be selectively brought closer to or separated from the table setting plate 1.

Further, square grooves facing in the centrifugal direction are formed on the upper surface of the outer peripheral edge and the upper surface of the inner peripheral edge of the tightening plate 9, respectively, so as to directly face the positioning pins 2, 3, 4 and the suction pin 5, which will be described later. Rubber rings 16 and 17 are press-fitted into the grooves.

The upper surface of each rubber ring 16, 17 is ground with reference to the bottom surface of the tightening plate 9, and the upper surface of steel ball receivers 18, 18 integrally fixed to the upper surface of each rubber ring 16, 17. is ground so that it is parallel to the bottom surface of the tightening plate 9.

The retainer plate 19 is a donut-shaped plate whose outer diameter is slightly smaller than the diameter of the annular groove 34 and whose inner diameter is slightly larger than the diameter of the annular groove 35. A groove 3 for inserting a steel ball is provided on the inner circumferential edge and the positioning pins 2, 3, 4 and the suction pin 5 to be described later, respectively.
6, 37... are drilled. Further, the retainer plate 19 is integrally fixed to the tightening plate 9 with bolts 22', 22', . . . , and a guide pin 2 press-fitted into the table set plate 1
2 and are fitted so that they can only slide in the axial direction.

The steel ball 10 is supported on the upper surface of the steel ball receiving seat 18, and is held in the grooves 36 and 37 in a manner that prevents it from escaping in the horizontal direction. Then, positioning pins and upward groove cams 32 are provided near the suction pins on the lower surface of the table set plate 1 near the outer circumference and on the inner circumference, respectively, so that the tightening plate 9 can be brought close to the table set plate 1. Steel ball 1
0 is moved toward the positioning pins 2, 3, 4 and suction pin 5 so that they can be crimped.

Note that 22 is a guide pin that allows the tightening plate 9 to slide relative to the table setting plate 1 without rotating.

The vacuum chucking device includes a vacuum seal plate that forms a space between the chucking plate 26 and a hollow suction pin 5 inserted and supported in a predetermined position of the table set plate 1 with a high-precision "clearance fit". 25, and a pipe joint 31 that communicates the space with a vacuum pump (not shown).

The attachment positions of the suction pins 5 are arranged concentrically with the positioning pins 2, 3, and 4 and alternately with the positioning pins 2, 3, and 4.

In addition, the suction pin 5 is connected to the chucking plate 2.
By providing a spring 11 between the table set plates 6 and 6, the table set plate 1 is always biased in a direction protruding from the table set plate 1.

Further, a suction rubber 23 having a gradually expanding tip is inserted and supported at the tip of the suction pin 5, and the tip of the suction rubber 23 can be inserted into the annular groove of the turntable.

Incidentally, reference numeral 24 denotes an adsorption rubber set pipe which is press-fitted into the inside of the adsorption rubber 23 to prevent the adsorption rubber 23 from coming off.

Therefore, when the tip of the suction rubber 23 comes into close contact with the annular groove of the turntable, the table setting plate 1, the tightening plate 9, and the vacuum sealing plate 25
An airtight chamber is formed by the chucking plate 26 and the chucking plate 26.

In addition, in order to improve the sealing performance of the airtight chamber,
The labyrinth function of the narrow grooves of the positioning pins 2, 3, 4 and suction pin 5 ensures airtightness between each pin and the table setting plate 1, and the tightening plate 9
By providing an O-ring 27 on the boss part of the table set plate 1, airtightness between the table set plate 1 and the table set plate 1 is ensured.
By providing an O-ring 28 on the sintered oil-impregnated bearing 15 through which each pin is inserted, the vacuum seal plate 2
5, an O-ring 29 is provided on the spring seat 13 that supports one end of the spring 11, and an O-ring 30 is provided on the lower surface of the outer peripheral edge of the vacuum seal plate 25. The airtightness between the pipe joint 31 and the chucking plate 26 is ensured by screwing the pipe joint 31 through the sealing tape.

In the figure, reference numeral 8 is a guide ring used when setting the turntable, and 6 and 7 are provided at predetermined positions on the table setting plate 1 to prevent the protrusion of the positioning pins 2, 3, 4 and the suction pin 5. It is a stopper ring that regulates.

FIG. 2 is a front view of the assembled and completed jig, which can be fixed to the main shaft of a lathe or the like using a mounting screw or a flange provided on the bottom surface of the tracking plate 26.

FIG. 6 shows an embodiment of the vacuum chuck system, in which the jig of the present invention is attached to a three-jaw chuck 40 set on the main shaft 39 of a lathe 38, and a through-hole drilled inside the main shaft of the lathe is installed. Insert the vinyl pipe 42 into the hole 41, and
One end is in communication with a pipe joint 31, and the other end is in communication with a vacuum pump 46 via a rotary seal coupling 43, a pressure reducing valve 44, and a vacuum tank 45, respectively.

The function of the jig of the present invention having the above structure is as follows. Before setting the turntable, the tightening plate 9 and the table setting plate 1 are in a separated state, so the steel ball 10 is in a free state between the cam groove 32 and the steel ball receiving seat 18, and the positioning pin 2, 3, 4 and the suction pin 5. Therefore, the positioning pins 2 and 3 and the suction pin 5 are connected to the stopper rings 6 and 7.
It is in a state where it protrudes so that it touches the .

When setting up the turntable, turn off the vacuum pump or open the pressure reducing valve.
First, place the guide ring 8 on the table set plate 1.
is inserted and held, and the turntable is pushed in until the annular groove 34 contacts the positioning pins 4, 4, 4 so that the center hole of the turntable fits into the guide ring 8.

At this time, positioning pins 2 and 3 and suction pin 5
is pushed against the springs 11 and 12, so
The positioning pins 2 and 3 and the suction pin 5 are connected to the spring 1
1 and 12 and comes into contact with the annular grooves 34 and 35 of the turntable. Here, the back pressure is
It is sufficient that the suction rubber 23 provided at the tip of the suction pin 5 is large enough to be deformed enough to exhibit a sealing effect, and therefore almost no distortion occurs in the turntable.

Thereafter, when the nut 20 is tightened using a T-shaped wrench or the like (not shown) and the tightening plate 9 is moved toward the table setting plate 1, the steel ball 10 moves along the gum groove 32 and is positioned. It makes point contact with the outer periphery of the pins 2, 3, 4 and the suction pin 5. If the nut 20 is further tightened, the steel ball 10 will be strongly pressed against each of the pins, the cam groove 32, and the steel ball receiving seat 18, so that the positioning pins 2, 3 and the suction pin 5 can be attached to the turntable. It can be held in a position that follows the annular grooves 34, 35.

During the above operation, the steel ball 10, the cam groove 3
2. Tolerances due to dimensional accuracy or division accuracy of each pin, retainer plate 19, etc. are determined by rubber ring 16,1
7, the turntable is supported by a large number of support points and suction points following the shape of the annular grooves 34 and 35.

Next, turn on the vacuum pump or close the pressure reducing valve to perform vacuum suction and reduce the vacuum pressure in the airtight chamber to approximately
The vacuum suction force is 25 inch Hg (635 mm Hg) or more, and the turntable can be attracted and fixed by the vacuum suction force.

Then, after confirming with a pressure gauge (not shown) that the vacuum pressure has increased sufficiently and reached the predetermined vacuum pressure, the hand that was setting the turntable or the turntable unit (not shown) , and remove the guide ring 8.

Therefore, in this state, the first reference surface 47 of the turntable can be cut by driving a lathe or the like.

At this time, when comparing the cutting resistance moment of the turntable, the frictional resistance moment between the suction rubber 23 and the annular grooves 34 and 35 of the turntable is sufficiently large, so that the turntable may slip or come off during the cutting operation. There is no risk of doing so.

Furthermore, since the turntable is chucked to avoid distortion, the reference surface on which the video disc is mounted can be cut with high precision.

After the cutting process is completed, the vacuum pump is turned off or the pressure reducing valve is opened to reduce the vacuum pressure in the airtight chamber, and the turntable is removed. Thereafter, the jig is cleaned by blowing off the cutting waste oil and the like adhering to the jig by blowing air or the like.

Then, by loosening the nut 20 using a T-shaped wrench or the like and separating the tightening plate 9 from the table setting plate 1 by hitting it with a mallet or the like, the positioning pins 2 and 3 by the steel balls 10 and the suction The lock of the pin 5 is released, and each pin 2, 3, 5 protrudes until it touches the stopper ring 6, 7 and returns to the initial state, preparing for the next cutting process.

The above has described an embodiment in which suction pins and positioning pins are arranged alternately, but as shown in FIG. 7, it is also possible to use pins that have the functions of both positioning pins and suction pins. This is preferable since no bending moment is generated due to force and the number of suction pins can be increased.

In addition, as shown in FIG. 8 as another example of the above,
It is also possible to provide the cam groove 32 on the upper surface of the tightening plate 9, and provide the retainer plate, steel ball receiver, and rubber ring on the table set plate.
In this case, the resistance of the suction pin and the positioning pin in the thrust direction can be increased.

As described above, in the jig of the present invention, all the support pins are reliably fixed at the same position while supporting the turntable at the upper ends of the support pins, so the position of the upper end support surface of the support pins is fixed. Stable without going crazy at all,
After that, when the turntable to be cut is chucked using vacuum suction power, no distortion occurs at all, and the support strength of the turntable is uniform because the many support pins are arranged evenly without bias. , there is no deformation during machining, and the record mounting surface of the turntable can be cut with high precision.

In addition, in the present invention, the dimensional tolerances of steel balls, cam grooves, pins, retainer plates, etc. are absorbed by the elastic deformation of the rubber ring during the fixing operation by the tightening plate, so when setting the turntable, There are no effects at all, the turntable can be held in an accurate position, and all support pins are kept in the same position with respect to the turntable, so there is no chance of the turntable being distorted by the effects of setting it. Moreover, it has many excellent effects such as a simple structure.

[Brief explanation of the drawing]

Figure 1 shows the assembled state of the turntable; the left half is a sectional view, the right half is a side view, and the second
The figure is a front view of the jig of the present invention, FIG. 3 is a longitudinal sectional view of the same, FIG. 4 is a cross-sectional view of FIG. 3, FIG. FIG. 7 is a simplified vertical cross-sectional view showing the chucking system; FIG. 7 is an enlarged vertical cross-sectional view of main parts showing another embodiment of the suction pin;
The figure is an enlarged vertical sectional view of the main part showing another embodiment of the pin locking mechanism. 1... Table set plate, 2, 3, 4... Positioning pin, 5... Adsorption pin, 9... Tightening plate,
DESCRIPTION OF SYMBOLS 10... Steel ball, 18... Steel ball receiver, 19... Retainer plate, 23... Adsorption rubber, 25... Vacuum seal plate, 26... Chucking plate, 32...
cam groove.

Claims (1)

[Claims] 1. A plurality of positioning pins that can be pressed against the bottom surface of the workpiece with a spring so as to follow the bottom shape of the workpiece, and a plurality of positioning pins that can be pressed against the bottom surface of the workpiece with a spring so as to follow the bottom surface shape of the workpiece. A plurality of suction pins that are provided and have suction portions communicating with the vacuum pump at their tips, a first plate having cam grooves on the inner and outer circumferences, a steel ball, and the cam grooves on the inner and outer circumferences correspond to a second plate into which the steel ball is loosely fitted in a position where the steel ball is loosely fitted, and the steel ball is moved along the cam groove by bringing the first plate and the second plate close to each other, and the positioning pin and A precision cutting jig for a turntable for a video disc, comprising a pin positioning device for fixing a suction pin.