JPS6381646A - Disk chucking device - Google Patents

Abstract

PURPOSE:To simplify constitution, to make the production inexpensive and to make an abrasion extremely small by abutting a thrust bearing member on the projection part of a clamp member and forming both members with a synthertic resin. CONSTITUTION:On the top of the clamp member 25 the projection part 53 is formed on which the clamp member pressing face part 55a of the thrust bearing member 55 is made to abut. And both the clamp member 25 and the thrust bearing member 53 are made of the synthethic resin, for example, a polyacetal is selected for the one and the resin such as a polybutylenetelephthalate, etc., is selected for the other. Therefore, since a usual steel ball is not used for the thrust bearing, the constitution is simplified, and since the members are easily made of the resin the cost of production is made inexpensive. And also a melt does not occur even in a non-lubricant state and the abrasion is made extremely small.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem F. Effect G. Example G-1 Structure of the example (Fig. 1) G -2 Experiments to confirm the effects of Example and its results (
FIGS. 2A and B) G-3 Modification H Effect of the invention A Industrial field of application The present invention is provided in a disc player or the like, and is designed to turn a disc by coming into contact with a disc placed on a turntable. This invention relates to a disk chucking device fixed on a table.

B. Summary of the Invention The present invention provides a disc pressing surface that presses the disc toward the turntable by contacting the periphery of the center of a disc placed on a turntable, and an end portion on the opposite side of the disc pressing surface. and a thrust receiving member having a clamp member pressing surface that abuts the tip of the projection of the clamp member and presses it toward the disk pressing surface. In the chucking device, at least the protruding portion of the clamp member is made of polyacetal and polybutylene terephthalate.
The clamp member and the thrust receiving member can be easily manufactured and obtained at low cost by forming one of them from polyacetal and the other from polybutylene lenticulate. , Moreover, when the clamp member rotates with the rotation of the turntable, under no lubrication,
Dissolution of the protruding portion of the clamp member and the clamp member pressing surface portion of the thrust receiving member can be avoided, and wear of both can be minimized.

C. Conventional technology In a disk player, a disk serving as an information recording medium is mounted on a turntable and rotated at a predetermined rotational speed, and information is recorded or recorded on a recording trunk portion of the rotating disk. The information recorded in the section is reproduced. In such a case, the disc is mounted on the turntable by placing the disc on the turntable with its center corresponding to the rotation axis of the turntable, and by sandwiching it between the disc and the turntable. It is fixed on the turntable by a disc chucking device that comes into contact with the disc.

FIG. 3 shows a state in which a disk is mounted on a turntable using a conventionally proposed disk chucking device. In FIG. 3, a disc D placed on the turntable 11 is fixed on the turntable 11 by a disc chucking device 21. As shown in FIG. The turntable 11 has a rotating shaft 13,
A center ring member 15 arranged around the center ring member 15 and engaged with the center hole Da of the disk D, and a center ring member 1
5, and includes a disk support member 17 that rotates together with the rotating shaft 13. In addition, centering member 1
A coil spring 19 is compressed between the disk support member 17 and the disk support member 17 . The disk D is placed on the turntable 11 with its center hole Da fitted into the centering member 15 and the peripheral portion of the center hole Da supported by the disk table portion 17a.

The disc chucking device 21 includes a turntable 11
A bearing member 2 that fits into the tip of a rotating shaft 13 provided in
3. It includes a clamp member 25 that is arranged to surround the bearing member 23 and abut against the disk D, and a holding member 27 that movably holds the clamp member 25. The clamp member 25 has a disk pressing surface portion 29 that faces the disk table portion 17a of the turntable 11 and presses the disk D by coming into contact with a peripheral portion of the center hole Da of the disk D supported by the disk table portion 17a; An end face part 33 is fixed to the end opposite to the disk pressing face part 29 and has a steel ball 31 embedded in the central part with a part of the steel ball 31 exposed.
The parts other than the steel ball 31 are made of, for example, synthetic resin. A clamp member 2 is provided at the center portion of the end surface portion 33.
A protrusion protruding toward the inside of the bearing member 5 is provided, and a coil spring 35 compressed between the end face portion 33 and the bearing member 23 is disposed around the protrusion. Further, the holding member 27 is provided with a clamp member engaging portion 37 that engages with the clamp member 25 to hold it, and the disk pressing surface portion 29 of the clamp member 25 is attached to the peripheral portion of the central hole a of the disk D. A thrust bearing having a clamp member pressing surface portion 39a that abuts the steel ball 31 disposed at the center portion of the end surface portion 33 of the clamp member 25 and presses the steel ball 31 toward the disk pressing surface portion 29 of the clamp member 25 when abutting the clamp member 25. A member 39 is provided. The thrust receiving member 39 is made of, for example, a synthetic resin material in which a ceramic plate forming the clamp member pressing surface portion 39a is embedded.

With this configuration, when the disk pressing surface portion 29 of the clamp member 25 is in contact with the peripheral portion of the center hole Da of the disk D supported by the disk table portion 17a of the turntable 11, the holding member 27 The thrust receiving member 39 disposed on the clamp member 25 brings its clamp member pressing surface 39a into contact with the steel ball 31 disposed on the clamp member 25 and presses it toward the disk portion. However, due to the disk pressing surface portion 29 of the clamp member 25, the turntable 11
is pressed toward the disc table portion 17a side and fixed onto the turntable 11.

Further, FIG. 4 shows the above-mentioned disk chucking device 21.
Disc chucking device 2 with a different configuration from
In this example, the thrust receiving member 39', which is provided on the holding member 27 and comes into contact with the steel ball 31 arranged at the center portion of the end face 33 of the clamp member, is made of polyacetal, for example. This synthetic resin is made of a synthetic resin material with relatively excellent wear resistance, and in this case, the thrust receiving member has a 39° angle.
The surface directly contacts the steel ball 31 to form a clamp member pressing surface portion 39a°.

D. Problems to be Solved by the Invention However, in the previously proposed disk chucking devices as described above, for example, in the case of the one shown in FIG. 3, the thrust receiving member is disposed on the clamp member. The clamp member that comes into contact with the steel ball is made of a synthetic resin material embedded with a ceramic plate that forms the pressing surface, so wear between the steel ball and the thrust receiving member can be minimized and good rotational characteristics can be obtained. However, the thrust receiving member has the drawback that the manufacturing process is complicated and the material cost is also increased, making it expensive. On the other hand, in the case of the one shown in FIG. 4, the thrust receiving member is integrally formed of, for example, polyacetal.
The manufacturing process is simple and it can be obtained at low cost, but after a long time of use, the pressing surface of the clamp member that contacts the steel ball in the thrust receiving member becomes noticeably worn, resulting in poor rotational characteristics. The problem is that it cannot be obtained.

In view of these points, the present invention provides a disk pressing surface that comes into contact with a disk placed on a turntable and presses the disk toward the turntable, and a disk pressing surface that is provided at an end opposite to the disk pressing surface. a clamp member having a protruding portion; and a thrust receiving member having a clamp member pressing surface portion that abuts the tip of the protruding portion of the clamp member and presses it toward the disk pressing surface portion; The receiving member can be obtained at a low cost, reducing costs. Furthermore, when the clamp member rotates with the rotation of the turntable, the protrusion of the clamp member and the thrust receiving member can be easily connected to each other under no lubrication. It is an object of the present invention to provide a disk chucking device that does not involve melting of a clamp member and a pressing surface portion, has extremely little wear on both parts, and is capable of obtaining good rotational characteristics.

E. Means for Solving the Problems In order to achieve the above-mentioned object, the disk chunking device according to the present invention abuts the periphery of the center of the disk placed on the turntable to move the disk toward the turntable. The turntable has a disc pressing surface that presses the turntable, and is provided at an end opposite to the disc pressing surface at a position that is on an extension line of the rotation axis of the turntable when the disc pressing surface is in contact with the disc. The thrust receiving member includes a clamp member having a protruding portion, and a thrust receiving member having a clamp member pressing surface portion that abuts the tip of the protruding portion of the clamp member and presses the protruding portion toward the disk pressing surface portion. and the clamp member has at least its protruding portion formed of one of polyacetal and polybutylene lenticulate, and
The thrust receiving member is made of the other of polyacetal and polybutylene terephthalate.

F Effect In the disk chucking device according to the present invention configured as described above, at least the protruding portion of the clamp member and the thrust receiving member are both made of synthetic resin, so that they are easy to manufacture and inexpensive. shall be obtained. Moreover, the synthetic resins forming at least the protruding part of the clamp member and the thrust receiving member having the clamp member pressing surface part that comes into contact with the protruding part are selected to be polyacetal on one side and polybutylene terephthalate on the other, so that the turntable can be When the clamp member rotates with rotation, under no lubrication conditions, the protruding part of the clamp member and the clamp member pressing surface of the thrust receiving member do not melt, and the wear of both is extremely small. will be done.

G Example G-1 Configuration of Example (Fig. 1) Fig. 1 shows an example of a disc chucking device according to the present invention used to attach a disc to a turntable similar to that shown in Fig. 3. Shows the state in which it is installed. In FIG. 1, parts corresponding to those shown in FIG. 3 are designated by the same reference numerals as in FIG. 3, and redundant explanation thereof will be omitted.

In the disk chucking device 41 shown in FIG. 1, which is an example of the disk chunking device according to the present invention, a disk D is opposed to the disk table portion 17a of the turntable 11 and is supported by the disk table portion 17a. An end surface portion 51 fixed to the end opposite to the disk pressing surface portion 29 of the clamp member 25 has a disk pressing surface portion 29 that presses the disk D by contacting the peripheral portion of the central hole Da of the clamp member 25. It is integrally formed of one of polyacetal and polybutylene terephthalate, for example, polyacetal, including the protrusion 53 provided in the central portion. The protrusion 53 provided at the center of the end surface 51 is configured to rotate around the rotation axis of the turntable 11 when the disk pressing surface 29 of the clamp member 25 is in contact with the peripheral portion of the center hole Da of the disk D. 13, and its tip forms part of a spherical surface having a relatively large radius. The actual protrusion 53 has a base diameter of approximately 15 to 30 m, for example.
m, and its tip forms part of a spherical surface with a radius of approximately 500 mm or more. Note that a protrusion that protrudes toward the inside of the clamp member 25 is also integrally formed in the center portion of the end face portion 51, and a constriction is formed between the end face portion 51 and the bearing member 23 around this protrusion. A coil spring 35 is arranged.

Further, the thrust receiving member 55 provided on the holding member 27 having the clamp member engaging portion 37 that engages with the clamp member 25 to hold the clamp member 25 is made of the other of polyacetal and polybutylene terephthalate, for example, polybutylene terephthalate. It is integrally molded from terephthalate. The thrust receiving member 55, which is integrally molded from polybutylene terephthalate, has a lower surface when the disk pressing surface portion 29 of the clamp member 25 comes into contact with the peripheral portion of the center hole Da of the disk D.
A protrusion 53 arranged at the center of the end surface 51 in 5
A clamp member pressing surface portion 55a is formed which contacts the tip of the clamp member and presses the protrusion portion 53 toward the disk pressing surface portion 29 of the clamp member 25.

That is, in the disc chucking device 41, when the disc D supported by the disc table part 17a of the turntable 11 is in the chucking state to be fixed on the disc table part 17a, the disc pressing surface part 29 A thrust receiving member 55 made of polybutylene terephthalate is attached to the tip of the protrusion 53 made of polyacetal of the clamp member 25 that presses the peripheral portion of the central hole Da of D.
The clamp member pressing surface portion 55a of the clamp member is brought into contact with and presses it. As a result, the clamp member 25 rotates as the turntable 11 rotates, and as a result, the protrusion 53 of the clamp member 25 rotates with its tip being pressed by the clamp member pressing surface 55a of the thrust receiving member 55. Even if such a state is taken, the protrusion 53 and the clamp member pressing surface 55a do not melt, and the wear of both is extremely small, resulting in excellent rotational characteristics.

Note that the end surface portion 51 including the above-mentioned protrusion portion 53 is not made of simple polyacetal but polyacetal mixed with 10% by weight of Teflon (hereinafter referred to as polyacetal 10T).
), and in such a case, the rotational characteristics will be even better.

G-2 Experiments to confirm the effects of Example and their results (
2A and B) Hereinafter, the protrusion 53 of the clamp member 25 made of polyacetal or polyacetal 10T, and the clamp member pressing surface 55a of the thrust receiving member 55 made of polybutylene terephthalate that abuts the tip thereof. Based on experimental results, we will discuss how excellent rotational characteristics can be obtained by using this method.

The inventor of the present application has developed a rod-like body Si (with a diameter of d) having a circular cross section with a flat end surface as shown in FIG. A rod-shaped body Qi is formed of polyacetal and polyacetal 10T, and a plate-shaped body Qi is formed of polybutylene terephthalate. force F on the plane
(kg), the rod-shaped body St is rotated at the rotation speed N (rpm), and the pressure that acts between the rod-shaped body St and the plate-shaped body Qi based on the force F at the melting limit of both. P=F・4/(π・d”)(kg/clT1
2) and the maximum circumferential speed of the tip of the rod-shaped body Si based on the rotation speed N
=π-N-d/60 (cm/5ec) value (
Hereinafter, the limit PV value) is determined at room temperature, and the second
The results shown in Figure B were obtained.

In Figure 2 B, the horizontal axis represents the maximum circumferential speed ■, and the vertical axis represents the pressure P.
The curve Ca shown by the broken line is, for example, when the rotation speed N is 180 Orpm, and
When the force F is 0.9 kg, that is, when the condition is set between the protrusion of the clamp member and the thrust member in contact with it in a disc chucking device applied to a normal video disc player, Necessary minimum limit PV for rod-shaped body Si and plate-shaped body Qi
In addition, the diameter d of the rod-shaped body Si is 0115~
A range of 0.3 (cm) is indicated as the practical range α. In FIG. 2B, for curve Ca, the result obtained in the above experiment when both rod-like body St and plate-like body Qi are formed of polyacetal is curved '!'! ! A
cb, and the result when the rod-like body Si is formed of polyacetal and the plate-like body Qi is formed of polybutylene terephthalate is shown by the curve Cc, and furthermore, when the rod-like body Si is formed of polyacetal 10T. The curve Cd shows the result when the plate-like body Qi is made of polybutylene ethylene terephthalate.

From the results shown in FIG. 2B, the curves Cc and Cd
In the practical range, the result obtained by curve Ca exceeds the necessary minimum p-v value, and the rotational speed N
is 180 Orpm, and the force F is 0.9 kg, that is, the condition between the protrusion of the clamp member and the thrust receiving member in contact with it in a disc chucking device applied to a normal video disc player. It was found that no dissolution occurs under
A rod-shaped body Si is formed of polyacetal 10T to form a plate-shaped body Q.
It can be seen that when i is formed from polybutylene terephthalate, the solubility limit is higher than when the rod-like body Si is formed from polyacetal and the plate-like body Qi is formed from polybutylene terephthalate.

From the above experimental results, as mentioned above, the clamp member 2
5 is formed of polyacetal or polyacetal 10T, and the thrust receiving member 55 having the clamp member pressing surface 55a that comes into contact with the tip of the projection 53 is formed of polybutylene terephthalate. A melting limit characteristic corresponding to the result obtained by the curve Cc or Cd in B is obtained, and even when the clamp member 25 rotates with the rotation of the turntable 11, the relationship between the protrusion 53 and the clamp member pressing surface 55a is maintained. It is understood that no dissolution occurs.

Further, the inventor of the present application has provided the clamp member 2 as described above.
Projection 53 formed of polyacetal in No. 5
A first state in which the clamp member pressing surface portion 55a of the thrust receiving member 55 formed of polybutylene terephthalate contacts the tip of the clamp member 25, and a first state in which the tip of the protrusion 53 formed of polyacetal 10T of the clamp member 25 is made of polybutylene terephthalate. In each of the second states in which the clamp member pressing surface 55a of the thrust receiving member 55 is in contact with each other, the clamp member pressing surface 55a of the thrust receiving member 55 presses the protrusion 53 with a force of 0.8 kg. , the protrusion 53 is 180Orp
As a result of an experiment in which the protrusion 53 was rotated at a rotational speed of m and continued for 2000 hours, it was found that the amount of wear at the tip of the protrusion 53 was approximately 130 μm in both the first state and the second state. It has been confirmed that the amount of abrasion concave portion of the clamp member pressing surface portion 55a was approximately 40 μm, which was extremely small.

Incidentally, as shown in FIG. 4, the clamp member pressing surface 39a' of the thrust receiving member 39'' made of polyacetal is attached to the steel ball 31 disposed at the center of the end surface 33 of the clamp member. When the steel balls 31 are in contact with each other, the steel balls 31 are rotated at a rotation speed of 1800 rpm while the clamp member pressing surface portion 39a' of the thrust receiving member 39' presses the steel balls 31 with a force of 0.8 kg. According to the experimental results, after such rotation was continued for only 600 hours, the amount of abrasion concavity in the clamp member pressing surface 39a' of the thrust receiving member 39' was approximately 350 μm.

From these experimental results, as in the example shown in Figure 1,
The protrusion 53 of the clamp member 25 is made of polyacetal or polyacetal 10T, and the protrusion 53
When the thrust receiving member 55 having the clamp member pressing surface portion 55a that comes into contact with the tip of the clamp member is formed of polybutylene terephthalate, the protrusion 53 and the clamp generated when the clamp member 25 rotates as the turntable 11 rotates. It is understood that the wear with the member pressing surface portion 55a is extremely small.

G-3 Modification In addition, in the example shown in FIG.
Although only the end face portion 51 on which the protrusion 53 in 5 is provided is formed of polyacetal or polyacetal 10T, the clamp member 25 is attached to the protrusion 5
The entire clamping member 25 may be made of polyacetal or polyacetal 10T.

Furthermore, the end surface portion 51 of the clamp member 25 where the protrusion portion 53 is provided, or the end surface portion 5 with the protrusion portion 53
The entire clamp member 25 including the clamp member 1 is made of polybutylene terephthalate, and the thrust receiving member 55 having the clamp member pressing surface portion 55a is made of polyacetal or polyacetal terephthalate.
In such a case, the same effects as in the above-mentioned example can be obtained.

H Effects of the Invention As is clear from the above description, the disk chucking device according to the present invention includes a disk pressing surface portion that comes into contact with the disk placed on the turntable and presses the disk toward the turntable; At least a protrusion of a clamp member having a protrusion provided at an end opposite to the disk pressing surface, and a clamp member pressing member that abuts the tip of the protrusion of the clamp member and presses it toward the disk pressing surface. Since the thrust receiving member having the surface portion is both made of synthetic resin, the clamping member and the thrust receiving member are easy to manufacture and can be obtained at low cost, thus reducing costs. It will be done. Furthermore, the synthetic resins forming at least the protruding part of the clamp member and the thrust receiving member having the clamp member pressing surface part that comes into contact with the protruding part are selected such that one side is polyacetetal and the other side is polybutylene terephthalate. When the clamp member rotates with the rotation of the turntable, under no lubrication conditions, the protruding part of the clamp member and the clamp member pressing surface of the thrust receiving member do not melt, and there is no abrasion of both. Since it is made extremely small, good rotational characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a disc chucking device according to the present invention together with a chucked disc and a turntable, and FIGS. 2A and B are effects of the disc chucking device according to the present invention. FIG. 3 is a sectional view showing a conventionally proposed disk chucking device together with a disk chucked by the device and a turntable; FIG. The figure is a sectional view showing a portion of another conventionally proposed disk chucking device. In the figure, 11 is a turntable, 25 is a clamp member, 2
7 is a holding member, 29 is a disk pressing surface portion, 41 is a disk chucking device, 51 is an end surface portion, 53 is a projection portion, 5
5 is a thrust receiving member, 55a is a clamp member pressing surface part,
D is a disk. Structure of Thrust Reception 1-O Example Fig. 1 Fig. 2 Portion of other conventional examples Fig. 4

Claims (2)

[Claims] (1) It has a disk pressing surface that comes into contact with the periphery of the center of the disk placed on the turntable and presses the disk toward the turntable, and an end opposite to the disk pressing surface. wherein the disk pressing surface portion has a protruding portion provided at a position on an extension line of the rotation axis of the turntable under a state in which the disk pressing surface portion is in contact with the disk, and at least the protruding portion is formed of polyacetal or polybutylene terephthalate. a thrust bearing member formed of polybutylene terephthalate or polyacetal, the clamp member having a clamp member pressing surface portion that contacts the tip of a protruding portion of the clamp member to press the protruding portion toward the disk pressing surface portion side; A disc chucking device comprising: and. (2) The protrusion of the clamp member has a base diameter of approximately 1
5 to 30 mm, and the tip has a radius of approximately 500 mm.
2. The disk chucking device according to claim 1, wherein the disk chucking device forms part of a spherical surface having a diameter of mm or more.