Disc clamping mechanism and disc drive device

A disc clamping mechanism includes a clamp board, a clamp base, a first supporting unit and a second supporting unit. The clamp board rotatably clamps a disc in cooperation with a turntable to be rotated in a housing. The clamp base rotatably supports the clamp board at a position opposite to the turntable, and is movable so as to move away from or come into contact with the turntable. The first supporting unit comes into contact with a first peripheral edge of the clamp board protruding from the clamp base when the clamp board moves away from the disc according to the movement of the clamp base, to exert pushing force in a direction of the turntable side and pushing force in a direction of the clamp base side against the first peripheral edge. The second supporting unit is provided at the clamp base, and securely supports the second peripheral edge of the clamp board situated at a position opposite to the first peripheral edge when the first peripheral edge is pushed by the first supporting unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a disc drive device used for recording desired music information and the like on a disc or reproducing the recorded information, and more particularly, to a disc drive device provided with a mechanism for clamping a disc.

2. Description of the Related Art

In general, a disc drive device such as a CD player or a DVD recorder is equipped with a turntable, an optical pickup and a disc clamping mechanism. The turntable supports a disc and rotates the disc. The optical pickup moves in a radial direction of the disc along a board surface of the disc. The disc clamping mechanism clamps the disc so that the disc disposed on the turntable may rotate in synchronization with the rotation of the turntable.

The disc clamping mechanism has a clamp base and a clamp board. The clamp base is movably provided in a housing of the disc drive device. The clamp board is rotatably supported by the clamp base. In the disc clamping mechanism, the clamp board comes closer to/off the turntable dependent on the movement of the clamp base. When the clamp board moves in a direction that it comes closer to the turntable, the disc is rotatably clamped on the turntable by the clamp board at the central part of the disc.

In the condition where the clamp board is rotatably supported by the clamp base, the clamp board has one or more free ends in an axial direction and/or a radial direction of the clamp board. Therefore, in the condition where the clamp board is away from the turntable, the clamp board is likely to rattle at each free end thereof when receiving external vibration. As a result, there is a problem that the disc drive device might produce a big noise.

In order to resolve the above-described problem, Japanese Patent Application Laid-Open No. H10(1998)-92099 discloses a construction configured to provide a spring over a clamp board (clamper). With this construction, when the clamp board moves away from a turntable, the spring presses the clamp board from above the clamp board to be elastically retained.

Further, Japanese Patent Application Laid-Open No. S60(1985)-214455 discloses a construction configured to rotatably support a clamp board (pushing member) by a supporting member made up of magnetic materials and to incorporate a magnet into the clamp board. With this construction, in the condition where the clamp board is away from a turntable (non-clamped state), the clamp board is attracted to the supporting member by its own magnetic force.

Furthermore, Japanese Patent Application Laid-Open No. H10(1998)-283740 discloses a construction configured to support a clamp board (clamper plate) made up of plastic magnet by a clamp base (clamper arm). With this construction, when the clamp board moves away from a turntable, the clamp board is attracted to a chassis by its own magnetic force.

However, with the construction disclosed in Japanese Patent Application Laid-Open No. H10(1998)-92099, it is necessary to provide the dedicated spring used for preventing the clamp board from rattling. This increases the number of parts, which leads to higher costs. Also, this requires to incorporate the spring into the disc drive device, which increases the number of man-hours to reduce productivity. Further, this requires a large gap between a chassis and the clamp board, which has an adverse effect on the reduction in thickness of the disc drive device. Furthermore, this may cause secondary damage caused by the resonance of the spring.

Further, with the construction disclosed in Japanese Patent Application Laid-Open No. S60(1985)-214455, it is necessary to provide on the top of the clamp board a buffer member used for preventing the clamp board from directly hitting a case (housing) by the vibration of the supporting member. This increases the number of parts, which leads to higher costs. Also, there is a possibility that the magnetic force of the clamp board acting on the supporting member might reduce rotational performance of the clamp board.

Furthermore, with the construction disclosed in Japanese Patent Application Laid-Open No. H10(1998)-283740, a peripheral edge of one end of the clamp board is only attracted to the chassis. Therefore, in a case that the disc drive device is used within a vibration system such as a vehicle-mounted type, the clamp board vibrates about a part where the clamp board is attracted to the chassis as a fulcrum point. As a result, there is a possibility that the disc drive device might produce a big noise.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a disc clamping mechanism and a disc drive device capable of ensuring the suppression of vibrations of a clamp board and preventing the generation of noises without the need to increase the number of parts.

To achieve the above-described object, the present invention provides the following (A) to (K):

(A) a disc clamping mechanism comprising a clamp board (51) that rotatably clamps a disc (D) in cooperation with a turntable (42) to be rotated in a housing (1); a clamp base (52) that rotatably supports the clamp board (51) at a position opposite to the turntable (42), and being movable so as to move away from or come into contact with the turntable (42); a first supporting unit configured to come into contact with a first peripheral edge (E1) of the clamp board (51) protruding from the clamp base (52) when the clamp board (51) moves away from the disc (D) according to the movement of the clamp base (52), to exert pushing force (F1) in a direction of the turntable side and pushing force (F2) in a direction of the clamp base side against the first peripheral edge (E1); and a second supporting unit provided at the clamp base (52), and configured to securely support a second peripheral edge (E2) of the clamp board (51) situated at an opposite side to the first peripheral edge (E1) when the first peripheral edge (E1) is pushed by the first supporting unit;

(B) The disc clamping mechanism according to (A), wherein the first supporting unit is a slope section (21c) formed in the housing (1);

(C) The disc clamping mechanism according to (A), wherein the first supporting unit is a slope section (21c) securely provided in the housing (1) as a member (21) separated from the housing (1).

(D) A disc drive device comprising: a housing (1); a turntable (42) to be rotated in the housing (1); and a disc clamping mechanism that rotatably clamps a disc (D) in the housing (1); the disc clamping mechanism comprising: a clamp board (51) that rotatably clamps the disc (D) in cooperation with the turntable (42); a clamp base (52) that rotatably supports the clamp board (51) at a position opposite to the turntable (42), and being movable so as to move away from or come into contact with the turntable (42); a first supporting unit configured to come into contact with a first peripheral edge (E1) of the clamp board (51) protruding from the clamp base (52) when the clamp board (51) moves away from the disc (D) according to the movement of the clamp base (52), to exert pushing force (F1) in a direction of the turntable side and pushing force (F2) in a direction of the clamp base side against the first peripheral edge (E1); and a second supporting unit provided at the clamp base (52) and configured to securely support a second peripheral edge (E2) of the clamp board (51) situated at an opposite side to the first peripheral edge (E1) when the first peripheral edge (E1) is pushed by the first supporting unit;

(E) The disc drive device according to (D), wherein the first supporting unit is a slope section (21c) formed in the housing (1); and

(F) The disc drive device according to (D), wherein the first supporting unit is a slope section (21c) securely provided in the housing (1) as a member (21) separated from the housing (1).

According to the present invention, even if the clamp board is moved away from the turntable, the first peripheral edge and the second peripheral edge are constrained by the first supporting unit and the second supporting unit, respectively, so that capability of suppressing vibrations of the clamp board and preventing the generation of noises are ensured. Also, since the first supporting unit and the second supporting unit are formed on existing parts without using springs or magnets, the generation of noises can be prevented by ensuring the suppression of vibrations of the clamp board, without the need to increase the number of parts.

In particular, in the case that the slope section is formed in the housing as the first supporting unit, the slope section can be also readily formed when the housing is molded. Also, even in the case that the slope section is provided to be fixed to the housing as the member separated from the housing, existing parts are utilized as the member, thereby the slope section can be formed to the existing parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a disc drive device provided with a disc clamping mechanism according to the present embodiment will be described in details with reference toFIGS. 1 to 8D.

FIG. 1is a schematic side view of internal structure of the disc drive device provided with the disc clamping mechanism according to the present embodiment.FIG. 2is a schematic plan view of the internal structure of the disc drive device provided with the disc clamping mechanism according to the present embodiment.

As illustrated inFIG. 1, a housing1forms an outer casing of the disc drive device. The housing1includes a base chassis11formed by press working of metal plate and a top board12for covering the top of the base chassis11. At the front face of the housing1, there is formed an opening13through which a disc D is to be carried into the housing1.

A disc conveying mechanism2is provided at the opening13side within the housing1. The disc conveying mechanism2includes a plate21for helping a disc to slide in contact therewith which is made of resin and securely provided on an inner side of the top board12, a flap plate22supported movably in a vertical direction of the disc drive device by brackets21a,21aprovided on both sides (frontward side and rearward side ofFIG. 1) of the plate21for helping a disc to slide in contact therewith, and a feed roller23rotatably provided along an inner edge of the flap plate22. Incidentally, the feed roller23is on standby at a position away from a position into which the disc D is to be carried, before the disc D is carried into the housing1. An actual standby position is situated a little higher than the position as shown with a solid line inFIG. 1.

When the disc D is carried into the housing1, the disc conveying mechanism2causes the feed roller23to move (turn) upward from the standby position while rotating the feed roller23, and then the disc D to be sandwiched between the feed roller23and the plate21for helping a disc to slide in contact therewith. Under this condition, the disc conveying mechanism2helps to carry the disc D into the housing1.

On the plate21for helping a disc to slide in contact therewith, there are formed convex lines21b,21bextending in a direction orthogonal to the direction in which the disc D is conveyed. Each convex line21bis set to have a gradually decreasing width from a bottom thereof at where it contacts the plate21for helping a disc to slide in contact therewith towards a top thereof, in a sectional view. Thus, each convex line21bslides in contact with only a peripheral edge of the disc D. As illustrated inFIG. 2, the feed roller23is set to have a gradually decreasing diameter from both ends thereof towards the central area thereof. Thereby, the convex lines21b,21band the feed roller23come into contact with only peripheral edges of the disc D. This allows the disc drive device to prevent the disc conveying mechanism2from causing wear and tear to a signal recording area of the disc D.

A sliding plate3is provided on an inner wall surface at one side of the base chassis11. A motor24activates the feed roller23to rotate positively and reversely. Also, driving force of the motor24is transmitted to the sliding plate3via a transmission mechanism (not shown). Thereby, the sliding plate3moves in the same direction as a direction that the disc D is being conveyed by the feed roller23.

As illustrated inFIG. 1, a drive unit4popularly known as “TRAMECHA” is constructed by assembling a turntable42and an optical pickup (not shown) and the like in one piece onto a seat plate41. The turntable42is a rotating member for supporting and rotating the disc D. The turntable42is directly connected to a rotor shaft of a spindle motor43firmly secured to the seat plate41. Thereby, the turntable42is driven to rotate when the rotor shaft rotates. The optical pickup is an electronic component unit for reading out recorded information of the disc D and writing information on the disc D while moving in a radial direction of the disc D supported by the turntable42. The optical pickup includes a light-emitting element such as laser diode that emits a light to be irradiated on a board surface of the disc D, and a light-receiving element that receives a reflected light from the disc D, or the like.

Incidentally, the seat plate41is supported by the base chassis11via an anti-vibration damper (not shown). Thereby, the disc drive device is capable of preventing of sound skip of reproduced sound that might be produced when the disc D is driven.

As illustrated inFIGS. 1 and 2, a disc clamping mechanism5includes a clamp board51for rotatably clamping the disc D in cooperation with the turntable42, and a clamp base52for rotatably supporting the clamp board51at a position opposite to the turntable42.

The clamp board51is a circular member with two-stepped construction where a large diameter portion51ato be crimped onto the central area of the disc D, and a small diameter portion51bhaving a smaller diameter than the large diameter portion51aare molded in one piece with synthetic resin. A linking portion (flat shell plate51c) for linking the large diameter portion51ato the small diameter portion51bis loosely fitted into a part (seat56) of the clamp base52, and supported by the clamp base52in a state where gaps are present in an axial direction and in a radial direction of the clamp board51(Refer toFIG. 6A).

The clamp base52is a plate-shaped member formed by press working of a metal plate. The clamp base52is coupled to the seat plate41of the drive unit4via coupling pins P, P in a cantilever condition. The clamp base52is vertically movable about the coupling pins P, P.

The clamp base52is biased in a direction in which the clamp board51approaches to the turntable42by a spring53spanned between the clamp base52and the seat plate41(Refer toFIG. 1). At one side of the clamp base52, a positioning pin54is provided to protrude (Refer toFIG. 2). The positioning pin54is pushed by a slope-shaped cam profile surface3aformed on the sliding plate3against biasing force of the spring53.

Before the disc D is carried into the housing1, since the positioning pin54is situated at the top of the cam profile surface3a, the clamp board51is away from the turntable42. When the disc D begins to be carried into the housing1, the sliding plate3moves leftward inFIG. 1in synchronization with the rotation of the feed roller23. By way of the movement of the sliding plate3, the positioning pin54slides down gradually on the slope surface from the top of the cam profile surface3a, and finally the central area of the disc D that has been carried-in is clamped by the turntable42and the clamp board51. Incidentally, when the disc D is clamped between the turntable42and the clamp board51, the feed roller23returns to the standby position and is away from the disc D.

FIG. 3illustrates a state where the disc D is being clamped between the turntable42and the clamp board51. In this state, by driving the spindle motor43, the turntable42, the disc D and the clamp board51rotate together in one piece. A ring-shaped frictional plate42ais stuck to the turntable42, thereby preventing the disc D from slipping.

On the other hand, when the disc D begins to be carried out of the housing1, the sliding plate3moves rightward inFIG. 1. The cam profile surface3acauses the positioning pin54to push upward by the movement of the sliding plate3, thereby causing the clamp board51to move away from the disc D against the biasing force of the spring53. When the clamp board51moves away from the disc D, the feed roller23moves upward from the standby position and then lifts the disc D from the turntable42. This causes the disc D to be sandwiched between the feed roller23and the plate21for helping a disc to slide in contact therewith.

As illustrated inFIG. 1, a slope section21c(a first supporting unit configured to constrain the clamp board51) is formed on the plate21for helping a disc to slide in contact therewith. When the clamp board51is away from the disc D, the slope section21cpushes a peripheral edge (a first peripheral edge) of the clamp board51which protrudes from the clamp base52(the details will be described later).

As illustrated inFIGS. 2 and 3, the clamp base52includes a main plate55and a sheet-shaped seat56. The main plate55has the coupling pins P, P, the positioning pin54, a small piece55aand flanges55b,55b. The seat56is mounted on the main plate55. The seat56supports the clamp board51. The small piece55aserves as a second supporting unit configured to constrain the clamp board51, and is opposed to a peripheral edge (a second peripheral edge situated at the opposite side to the first peripheral edge) of the small diameter portion51bof the clamp board51when the disc D is clamped. The flanges55b,55bare at the both sides of the small piece55a.

As illustrated inFIGS. 3 and 4, the small piece55ais formed in the shape of the letter J by bending downward a part of the main plate55. An end edge of the small piece55aside of each flange55bis subjected to a plastic deformation upward. At a bottom surface side of the plastically deformed end edge, a bottom raised portion55cis formed. When the clamp board51moves away from the disc D, the peripheral edge (the second peripheral edge) of the small diameter portion51bgets on the small piece55a, and the both sides of the small diameter portion51bcome into close contact with the bottom raised portions55c,55cof the flanges55b,55b(Refer toFIG. 5). Thereby, the clamp board51is securely supported by the clamp base52and the plate21for helping a disc to slide in contact therewith.

As illustrated inFIG. 6A, a notched hole56ais formed at the seat56. The flat shell plate51cof the clamp board51(the linking portion for linking the large diameter portion51ato the small diameter portion5b) is loosely fitted to the notched hole56a. As illustrated inFIG. 6B, a stepped portion56bis formed at the seat56by folding the seat56in a width direction. Since the notched portion56ais formed by straddling the stepped portion56b, a restricted portion of the clamp board51(the flat shell plate51c) is simply introduced from the position of the stepped portion56binto the notched hole56a. Also, plate springs56c,56care formed at the both sides of the notched hole56a. The plate springs56c,56care adapted to prevent the clamp board51from withdrawing from the notched hole56a.

Next, referring toFIGS. 7A to 8D, action of the disc clamping mechanism5will be described.

FIGS. 7A to 7Dare illustrative views showing the action of the disc clamping mechanism5, when the clamp board51moves away from the disc D.FIGS. 8A to 8Dare enlarged views illustrating essential parts as illustrated inFIGS. 7A to 7D.

When the clamp board51moves away from the disc D (not shown), that is, moves upward to a top board12side, a first peripheral edge E1of the clamp board51which protrudes from the clamp base52comes into contact with the slope section21cformed on the plate21for helping a disc to slide in contact therewith. Incidentally, the slope section21cis formed at a tip end21d(Refer toFIG. 2) of the plate21for helping a disc to slide in contact therewith.

Since the slope section21cis formed at the clamp board51side of the plate21for helping a disc to slide in contact therewith, pushing force F1in a direction of the turntable42side and pushing force F2in a direction of the clamp base52side act from the slope section21ctoward the first peripheral edge E1of the clamp board51when the first peripheral edge E1comes into contact with the slope section21c. Incidentally, the pushing force F1and the pushing force F2are components of force F acting in a direction perpendicular to the slope section21c. The clamp board51is pushed downward at the first peripheral edge E1side by the slope section21c,and is moved to the cramp base52side. Thereby, while the first peripheral edge E1remains to receive the pushing force F1and the pushing force F2from the slope section21c, the second peripheral edge E2are clamped between the small piece55aand the flanges55b,55band thus being securely supported by the clamp base52. That is, the clamp board51is reliably and securely supported in the axial direction and in the radial direction of the clamp board51by the clamp base52and the plate21for helping a disc to slide in contact therewith.

Since the clamp board51is completely constrained by the slope section21c(a first supporting unit) and the small piece55aand the flanges55b,55b(a second supporting unit), even if external vibration propagates to the clamp board51, the clamp board51will not rattle. As a result, the disc drive device can prevent the generation of noises.

Next, modified embodiments of the present embodiment will be described.

The slope section21cmay be formed at the top board12constituting the housing1, not limited to the plate21for helping a disc to slide in contact therewith. Incidentally, since the plate21for helping a disc to slide in contact therewith is a component to be fixed to the top board12, it can be also regarded as a part of the top board12. Consequently, even if the slope section21cis formed on the plate21for helping a disc to slide in contact therewith, it may be said that the slope section21chas been formed on the housing1.

An inclined surface of the slope section21cis not limited to a plane, but may be a curved surface. In particular, the inclined surface of the slope section21cmay be linear like the tip end21d(Refer toFIG. 2) of the plate21for helping a disc to slide in contact therewith, or may be an arc-shaped along a peripheral edge of the clamp board51.

The second supporting unit is preferably composed of the small piece55aand the flanges55b,55. However, as illustrated inFIG. 8D, a lower end of the small piece55acomes into contact with the top surface of the large diameter portion51aof the clamp board51, in a state where the clamp board51is constrained. As a result, the second supporting unit prevents the second peripheral edge E2from moving upward, so that the flanges55b,55bmay be omitted. However, even in the case that the second supporting unit is composed of only the small piece55a, the small piece55ais not intended to be formed at the clamp base52, but the small piece55amay be fastened to the clamp base52as a member separated from the clamp base52.