JPH09198761A - Clamp rotation mechanism for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost through omission of force-fitting work and utilization of an inexpensive magnet by forming a rotor part by press work, joining this part integrally with a turntable by welding and utilizing the magnet of a low magnetic flux density. SOLUTION: The rotor part 30A is formed by drawing press work. First, a step part 37 is extended in the outer circumferential direction from an upper part of a cylindrical shaft part 33 to be freely rotatably inserted into a bearing 21 on the side of a stator, and moreover, a bent part 34 bent downward the part 37 is horizontally extended. The lower surface side of the turntable 25 and the lower surface side of a clamper magnet 26a are joined to the bent part 34 by welding. Moreover, a yoke part 30a, to which a rotor magnet 29 is fixed, is provided orthogonally to an outer circumference of the turntable 25. The magnet of a low magnetic flux density is utilized for the clamper magnet 26a as in a discoid shape with no center hole. Consequently, the force-fitting work of a hub onto a spindle can be omitted, thus facilitating the alignment of their axial centers. In addition, the inexpensive magnet can be utilized, and the cost can thus be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium clamping and rotating mechanism for clamping an information recording medium such as a magnetic disk or an optical disk to give a rotational force.

[0002]

2. Description of the Related Art A clamp rotation mechanism that clamps an information recording medium such as a magnetic disk or an optical disk to give a rotational force is provided between a turntable and a central portion of the information recording medium placed on a turntable by a clamper. A configuration is adopted in which the information recording medium is rotated by a spindle motor while being sandwiched.

That is, FIG. 3 shows one form of a conventional clamp rotating mechanism, in which a sleeve 22 in which a bearing 21 of a spindle motor 20 is mounted is attached to a chassis 10, and a stator coil 23 is fixed to the outer periphery thereof. Has been done.

A tip end of a spindle shaft 24 rotatably supported by a bearing 21 is press-fitted into a center hole of a centering hub 27 of a resin turntable 25.
A ring-shaped clamper magnet 26 is integrally formed with the centering hub 27.

A ring-shaped anti-slip member 28 is fixed to the outer peripheral portion of the turntable 25 so as to come into contact with the central portion of the disk 40 to provide an anti-slip action. On the lower surface side of the turntable 25, a yoke 30 constituting a rotor portion 30C to which a ring-shaped rotor magnet 29 is fixed inside is attached. Further, the engagement member 31 fixed to the lower surface side of the centering hub 27 engages with the engagement piece portion 32 of the sleeve 22 to prevent the turntable 25 from coming off.

On the other hand, the metal plate 51 attracted to the magnet 26 is fixed to the central portion of the clamper 50 for sandwiching the central portion of the disk 40 placed on the turntable 25 with the turntable 25. Has been done. Further, a pressing portion 52 is provided on the lower surface side of the clamper 50 at a position corresponding to the anti-slip member 28.
At the time of clamping, the central portion of the disk 40 is pressed against the turntable 25 side by the pressing portion 52 of the clamper 50.

[0007]

In the clamp rotating mechanism described above, when the resin turntable 25 is attached to the spindle shaft 24, the tip end portion of the spindle shaft 24 is inserted into the center hole of the centering hub 27. Since it is designed to be press-fitted, the press-fitting is not only time-consuming, but there is a problem that the turntable 25 and the spindle shaft 24 are difficult to align with each other, and the fitting length is short. Due to this, there is also a problem that it is difficult to maintain vertical accuracy.

Further, the clamper magnet 26 integrally formed with the centering hub 27 needs to be ring-shaped so that a center hole for press-fitting into the tip end of the spindle shaft 24 is formed, and in order to generate a clamping force. Requires an expensive sintered magnet such as Nd (neodymium) having a high magnetic flux density, which causes a problem of cost increase.

The present invention has been made in view of the above circumstances, and provides an information recording medium capable of improving the assemblability of various parts, improving the axial center accuracy, and further reducing the cost. An object is to provide a clamp rotating mechanism.

[0010]

According to the first aspect of the present invention,
A table part, which is joined to the rotor part of the spindle motor and carries an information recording medium centered by a resin hub part, and the central part of the information recording medium is pressed against the table part side to clamp the information recording medium. A clamp rotation mechanism for an information recording medium, comprising: a clamper having a metal plate, which is rotatably inserted into a bearing on the stator side in the rotor portion by drawing press working of a plate member. A cylindrical shaft portion, a joint portion extending in the outer peripheral direction from the upper end of the shaft portion and surface-joined to the lower surface side of the table portion, and a rotor magnet mounted below the outer periphery of the joint portion and attached. And a disk-shaped clamp magnet is integrated by insert molding on the hub portion of the table portion. When the information recording medium is clamped by, the metal plate on the clamper side is attracted by the clamp magnet of the hub portion, so that the central portion of the information recording medium is sandwiched between the table portion and the rotor portion. The information recording medium is rotated by the rotational driving of the above.

According to a second aspect of the present invention, a table portion, which is joined to the rotor portion of the spindle motor and on which the information recording medium centered by the hub portion is placed, and the central portion of the information recording medium are on the table portion side. A clamp rotation mechanism for an information recording medium, comprising a resin clamper for pressing the information recording medium to clamp the information recording medium, wherein the rotor portion is formed by drawing press working of a plate member with respect to a bearing on the stator side. A cylindrical shaft portion that is rotatably inserted, a hub portion that extends in a convex shape from the upper end of the shaft portion in the outer peripheral direction, and a horizontal portion that extends horizontally from the outer periphery of the hub portion during the drawing press processing. A joint portion that is surface-joined to the table portion and a yoke portion that extends below the outer periphery of the joint portion and on which the rotor magnet is mounted are formed, and a disk shape is provided on the clamper side. A clamp magnet is integrated by insert molding, and when the information recording medium is clamped by the clamper, the hub portion is attracted by the clamp magnet on the clamper side, so that the information recording is performed with the table portion. The center portion of the medium is sandwiched, and the information recording medium is rotated by rotationally driving the rotor portion.

[0012]

In the clamp rotation mechanism for an information recording medium of the present invention, the rotor portion is pierced through the bearing on the stator side by the squeeze press working, and the cylindrical shaft portion is rotatably inserted.
It is formed by a joint portion extending from the upper end of the shaft portion in the outer peripheral direction and surface-joined to the lower surface side of the table portion, and a yoke portion extending below the outer periphery of the joint portion and having a rotor magnet attached thereto. Assembling on the spindle motor side is completed by rotatably inserting the shaft portion of the rotor portion, in which the table portion is joined to the joint portion, into the bearing on the stator side.

Therefore, since there is no need for the work step of press-fitting the center hole of the centering hub of the turntable to the spindle shaft as in the above-mentioned conventional technique, the press-fitting is not troublesome and the rotor portion is joined. Since the lower surface side of the table portion is surface-bonded to the portion, it becomes easy to match the respective axial centers of the rotor portion side and the table portion side.

Further, in the hub portion, the central hole for press-fitting the spindle shaft is not required unlike the above-mentioned conventional case, so that the clamper magnet can be formed into a disk shape without the central hole, and the magnet surface can be widened. Therefore, since the total amount of magnetic flux is increased, it is possible to use an inexpensive magnet having a low magnetic flux density, such as ferrite, without requiring a high magnetic flux density unlike the conventional Nd sintered magnet described above. The cost of the mechanism can be reduced.

Further, when the rotor portion is formed by drawing press working, the hub portion is also formed at the same time, and the table portion is simultaneously surface-joined to the joining portion during drawing pressing work. Is extremely easy to mold.

Further, since the disk-shaped clamp magnet is integrated with the resin clamper side by insert molding, the hub portion is attracted by the clamp magnet on the clamper side when the information recording medium is clamped. The metal plate provided on the clamper side can be omitted, and the number of parts can be reduced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings described below, the same parts as those in FIG. 3 are designated by the same reference numerals, and overlapping description will be omitted.

FIG. 1 shows an embodiment of a clamp rotation mechanism for an information recording medium according to the present invention, in which a rotor portion 30A is integrally formed by drawing and pressing a metal plate.

That is, the step portion 37 is extended in the outer peripheral direction from the upper end of the cylindrical shaft portion 33 that is rotatably inserted in the bearing 21 on the stator side, and is lowered by one step from the outer periphery of the step portion 37. The bent portion 34 extends horizontally, and a yoke portion 30a to which the rotor magnet 29 is fixed is hung so as to be orthogonal to the bent portion 34 at the outer periphery thereof.

Here, the bent portion 34 and the step portion 37 are P
It is a joint to the turntable 25 made of C (polycarbonate). In addition, the cylindrical shaft portion 3 shown in the figure
Although the inside of 3 is hollow, the rigidity of the shaft portion 33 may be increased by inserting a tubular member into the hollow portion.

An engagement member 31 is fixed to the lower surface of the step portion 37, and the engagement of the engagement piece portion 32 of the sleeve 22 prevents the rotor portion 30A from coming off. The centering hub 27 of the turntable 25 is integrated with a clamper magnet 26a, which is an inexpensive sintered product such as a disk-shaped ferrite without a central hole, by insert molding, and the lower surface of the clamper magnet 26a is the rotor portion 30A. By directly contacting the upper surface of the stepped portion 37 without any gap,
It contributes to the function as a back yoke and the clamping force.

Then, a locking projection 36 projecting from the lower surface of the turntable 25 is locked in a locking hole 35 formed in the bent portion 34, and the bent portion 3 which is a joint portion.
4 and the step portion 37 are surface-bonded to the lower surface side of the turntable 25 and the lower surface side of the clamper magnet 26a by welding or the like. On the other hand, the form of the clamper 50 for sandwiching the central portion of the disk 40 placed on the turntable 25 with the turntable 25 is the same as the conventional one.

Next, the operation of the clamp rotating mechanism having such a structure will be described. First, when the disc 40 is placed on the turntable 25 by loading, the centering hub 27 is fitted into the center hole of the disc 40, thereby centering the disc 40.

Next, when the clamper 50 descends and the metal plate 51 is attracted by the clamper magnet 26a, the disc 40 is pressed by the pressing portion 52 of the clamper 50.
The central portion of the disk 40 is pressed, and the central portion of the disc 40 is sandwiched between the disk 40 and the turntable 25. At this time, the lower surface side of the central portion of the disk 40 is pressed against the anti-slip member 28 on the turntable 25, so that the disk 40 is sandwiched so as not to slip in the rotational direction between the turntable 25 and the clamper 50. It

In this state, when a drive current is supplied to the stator coil 23, the reaction with the magnetic force from the stator coil 23 causes the rotor portion 30A to which the rotor magnet 29 is attached to rotate, and the rotor portion 30A is mounted on the turntable 25. The placed disk 40 is rotated.

At this time, the bent portion 3 on the rotor portion 30A side
4 and the step portion 37 are surface-bonded to the lower surface side of the turntable 25 and the lower surface side of the clamper magnet 26a integrated with the centering hub 27, respectively, and
Since the cylindrical shaft portion 33 is assembled so as to be rotatably inserted into the stator-side bearing 21, the respective shaft centers of the rotor portion 30A side and the turntable 25 side are easily aligned. Therefore, the rotation of the disk 40 is performed in a stable state.

As described above, in this embodiment, when the rotor portion 30A is formed by the drawing press working, the step portion is formed from the upper end of the cylindrical shaft portion 33 which is rotatably inserted into the bearing 21 on the stator side. 37 is extended in the outer peripheral direction, and the bent portion 34 is horizontally extended in a state of being lowered by one step from the outer periphery of the step portion 37. The fixed yoke portion 30a is hung so that the bent portion 34 and the step portion 37, which are joint portions, are attached to the lower surface side of the turntable 25 and the clamper magnet 26.
The lower surface side of "a" is surface-bonded by welding or the like, and the shaft portion 33 of the rotor portion 30A is rotatably inserted into the bearing 21 on the stator side so that the spindle motor side can be assembled.

Therefore, the work process of press-fitting the spindle shaft 24 into the center hole of the centering hub 27 of the turntable 25 is eliminated as in the conventional case described above, so that the press-fitting is not troublesome and the rotor is not required. Since the lower surface side of the turntable 25 is surface-bonded to the joint portion of the portion 30A, it becomes easy to match the respective axial centers of the rotor portion 30A side and the turntable 25 side.

Further, in the centering hub 27,
Since the central hole press-fitted into the spindle shaft 24 is not required unlike the above-described conventional case, the clamper magnet 26a can be formed into a disk shape without the central hole, and a wide magnet surface can be obtained. Since a high magnetic flux density such as Nd sintered magnet is not required and an inexpensive magnet such as ferrite can be used, the cost of the mechanism can be reduced.

FIG. 2 shows another embodiment in which the form of the clamp rotating mechanism of FIG. 1 is changed. When the rotor portion 30B is formed by drawing press working, the centering hub portion 27a is also formed. A form in which the clamper magnet 26a is formed at the same time, the table portion 38, which is a press-worked component, is surface-joined to the bent portion 34, which is a joint portion at the time of drawing press work, and the clamper magnet 26a is provided on the PC (polycarbonate) clamper 50 side. Is taken.

When the table portion 38 is joined to the bent portion 34, the protrusion 36a of the bent portion 34 is fitted into the hole 38a of the table portion 38, so that the two are joined more firmly. ing.

Further, the engaging member 31 for preventing the rotor portion 30B from coming off is fixed to the inside of the centering hub portion 27a. On the other hand, on the side of the clamper 50, an inexpensive clamper magnet 26a such as the above-mentioned ferrite is integrated by insert molding in the central portion thereof,
When clamping, the metal centering hub 2
The upper end of 7a is attracted by the clamper magnet 26a.

Therefore, in this embodiment, when the rotor portion 30B is formed by the drawing press working, the centering hub portion 27a is also formed at the same time, and the bending portion 34 which is the joint portion is pressed during the drawing press working. Since the table portion 38, which is a component, is surface-joined at the same time, the rotor portion 30B and the table portion 38 are
Is extremely easy to mold, and the centering hub portion 27a and the spindle motor side shaft portion 33a can be made to coincide with each other at the transfer level of the mold accuracy.

When the disk 40 is clamped, the centering hub portion 27a is attracted by the clamp magnet 26a on the clamper 50 side, so that the metal plate 51 provided on the clamper 50 side can be omitted, and the parts can be omitted. The points can be reduced.

[0035]

As described above, according to the clamp rotation mechanism of the information recording medium of the present invention, the shaft portion of the rotor portion in which the table portion is joined to the joint portion is rotatable with respect to the bearing on the stator side. Since the spindle motor side is assembled by inserting the center hole of the turntable into the spindle shaft, there is no need for the work process of press-fitting the center hole of the centering hub of the turntable to the spindle shaft. Since the lower surface side of the table portion is surface-bonded to the joint portion of the rotor portion, it is easy to match the respective axial centers of the rotor portion side and the table portion side. .

Further, in the hub portion, as in the conventional case,
Since the center hole for press-fitting the spindle shaft is not required, the clamper magnet can be made into a disk shape without a center hole, and the magnet surface can be widened, so that the total amount of magnetic flux can be increased. Since a low magnetic flux density magnet such as ferrite can be used without requiring a high magnetic flux density like an Nd sintered magnet, the cost of the mechanism can be reduced.

Further, when the rotor portion is formed by drawing press working, the hub portion is also formed at the same time, and the table portion is simultaneously surface-joined to the joining portion at the time of drawing press working. Is extremely easy to mold.

Further, when the information recording medium is clamped, the hub portion is made to be attracted by the clamp magnet on the clamper side. Therefore, the metal plate provided on the clamper side can be omitted and the number of parts can be reduced. .
Therefore, the assemblability of various parts can be improved, the axial center accuracy can be improved, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a clamp rotation mechanism for an information recording medium of the present invention.

FIG. 2 is a sectional view showing another embodiment in which the form of the clamp rotation mechanism of FIG. 1 is changed.

FIG. 3 is a cross-sectional view showing a conventional clamp rotation mechanism.

[Explanation of symbols]

 21 bearing 23 stator coil 25 turntable 26a clamper magnet 27 centering hub 27a centering hub part 29 rotor magnet 30a yoke part 30A, 30B rotor part 38 table part 40 disk 50 clamper 51 metal plate

Claims (2)

[Claims] 1. A table part, which is joined to a rotor part of a spindle motor, on which an information recording medium centered by a hub part made of resin is placed, and a central part of the information recording medium is pressed against the table part side. A clamp rotation mechanism for an information recording medium, comprising: a clamper having a metal plate for clamping the information recording medium, wherein the rotor portion is rotated with respect to a bearing on the stator side by drawing press working of a plate member. A cylindrical shaft portion that is freely inserted, and a joint portion that extends from the upper end of the shaft portion in the outer peripheral direction and is surface-joined to the lower surface side of the table portion,
A yoke portion is formed below the outer periphery of the joint portion, and a rotor magnet is mounted on the yoke portion. A disk-shaped clamp magnet is integrated with the hub portion of the table portion by insert molding. When the information recording medium is clamped, the metal plate on the clamper side is attracted by the clamp magnet of the hub portion, so that the central portion of the information recording medium is sandwiched between the table portion and the rotor portion, A clamp rotation mechanism for an information recording medium, wherein the information recording medium is rotated by rotational driving. 2. A table part, which is joined to a rotor part of a spindle motor, and on which an information recording medium centered by a hub part is placed, and the central part of the information recording medium is pressed against the table part side, thereby the information recording medium. Is a clamp rotation mechanism for an information recording medium, which is equipped with a resin clamper that clamps the plate. The rotor part is rotatably inserted into a bearing on the stator side by drawing press working of a plate member. A cylindrical shaft portion, a hub portion that is convexly extended from the upper end of the shaft portion in an outer peripheral direction, and a hub portion that is horizontally extended from the outer periphery of the hub portion and is surface-bonded to the table portion during the drawing press working. And a yoke portion that extends below the outer periphery of the joint portion and on which the rotor magnet is mounted are formed, and a disk-shaped clamp magnet is provided on the clamper side. It is integrated by insert molding, and when the information recording medium is clamped by the clamper, the hub portion is attracted by the clamp magnet on the clamper side, so that the center of the information recording medium is formed between the hub portion and the table portion. A clamp rotation mechanism for an information recording medium, wherein the information recording medium is rotated by rotationally driving the rotor section.