JP2009080876A - Clamp for disk rotation drive unit and clamp manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable regulation of a weight increase according to a wall thickness increase and disable generation of a weight balance error in the circumferential direction. <P>SOLUTION: A clamp 1 for a disk rotation drive unit comprises a central part 9 fixed on a hub which can be driven to rotate and circumferentially a contact part 5 at an outer periphery 3, and fixes a magnetic disk 7 onto a hub by bringing the contact part 5 into contact with the magnetic disk 7 which is mounted on the hub and records information to apply a pressing force in the direction of the rotational axis. A C ring 105 for adjusting rotation balance, an overhang 21 which can retain in the rotational direction, and a locking wall 15 which protrudes radially inward are set circumferentially at preset intervals at the outer periphery 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a clamp of a disk rotation drive device such as a hard disk drive (HDD “Hard Disk Drive”) used in an information processing apparatus such as a computer, and a clamp manufacturing method.

  Conventionally, there is one disclosed in Patent Document 1 as a clamp of a disk rotation driving device.

  This clamp is attached by a balance ring (wire balancer), which is attached to adjust the rotational balance, disposed in the annular groove and locked in the radial direction or the rotational direction. This balance ring can suppress rotational runout during motor rotation.

  However, since the balance ring has a structure that is locked in the radial direction or the rotation direction, the rotation in the rotation axis direction is insufficient, and the balance ring may fall out in the rotation axis direction when an impact is input.

  On the other hand, the structure of the reference example shown in FIGS. 4 is a plan view of the clamp, FIG. 5 is a plan view of the C-ring, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  As shown in FIGS. 4 to 6, the clamp 101 includes a locking wall 103 on the outer peripheral portion, and the C-ring 105 that is the C-type balance ring shown in FIG. It is fitted to become. The C-ring 105 is elastically locked to the locking wall 103 with an elastic force in the opening direction, and the overhang portion 107 prevents the C-ring 105 from coming off in the rotation axis direction with respect to the clamp 101.

  However, when the overhang portion 107 is simply formed, the thickness of the overhang portion 107 increases, and there is a problem that the weight increases and the balance error of the weight tends to be caused in the circumferential direction.

  Such a problem is caused when the overhang portion 107 is formed by either press molding or cutting. In particular, in the press molding, the shape of the overhang portion (convex portion) is caused by a large bending resistance. Due to the variation, it is easy to cause a weight balance error in the circumferential direction.

WO2003 / 001522

  The problem to be solved is that when the overhang portion is simply formed, the thickness of the overhang portion increases, the weight increases accordingly, and a balance error of the weight tends to be caused in the circumferential direction.

  In press molding, the bending resistance is large, and variation in the shape of the overhang portion (convex portion) tends to cause a weight balance error in the circumferential direction.

  In the present invention, in order to suppress an increase in weight due to an increase in wall thickness while forming an overhang portion, and to make it difficult for a weight balance error to occur in the circumferential direction, the central portion is fixed to a rotating body that can be rotationally driven. In addition, the outer peripheral portion is provided with an abutting portion in a circular shape, and the disc is mounted by contacting the abutting portion with a disc mounted on the rotating body and capable of recording information, thereby applying a pressing force in the rotational axis direction. In the clamp of the disk rotation drive device that supports the rotating body fixedly on the rotating body, an overhang portion that can be locked to prevent the balance ring for adjusting the rotation balance from coming off in the rotation axis direction protrudes radially inward at the outer peripheral portion. The most important feature of the clamp is that the provided locking walls are arranged in a circular pattern at predetermined intervals.

  In addition, when the overhang portion is formed by press working, in order to reduce bending resistance in the bending process and make it difficult to cause a weight balance error in the circumferential direction, the clamp half including the portion that becomes the locking wall of the clamp is included. The most important feature of the clamp manufacturing method is that it includes a step of punching a product from a clamp material and a step of forming the overhang portion by bending a portion of the clamp semi-finished product to be the locking wall. To do.

  The clamp according to the present invention has a central portion fixed to a rotary body that can be driven to rotate, and has a contact portion in a circular shape on an outer peripheral portion, and the contact portion is attached to a disk that is attached to the rotary body and can record information. In the clamp of the disk rotation driving device that fixedly supports the disk on the rotating body by applying a pressing force in the direction of the rotation axis by contacting the disk, a balance ring for adjusting the rotation balance is provided on the outer peripheral portion. A locking wall having an overhang portion projecting radially inwardly that can be prevented from being locked in the direction of the rotation axis is arranged in a circular shape at predetermined intervals.

  For this reason, an increase in weight can be suppressed while having an overhang portion. Moreover, the balance error of the weight in the circumferential direction can be suppressed by suppressing the increase in weight, suppressing the bending resistance, or the like.

  The clamp manufacturing method of the present invention includes the step of punching a clamp semi-finished product including a portion that becomes a locking wall of the clamp from the clamp material, and bending the portion of the clamp semi-finished product that should be the locking wall. Forming an overhang portion.

  For this reason, when the overhang portion is formed by press working, the resistance can be reduced in the case of bending a portion that becomes a locking wall at a predetermined interval as compared to bending a circular blank, and the overhang portion ( It is possible to suppress variations in the shape of the convex portion and to prevent a balance error in weight in the circumferential direction.

  While forming the overhang part, while suppressing the increase in weight due to the increase in wall thickness and making it difficult to cause an error in the balance of the weight in the circumferential direction, a locking wall with the overhang part protruding radially inward is provided. This was realized by arranging in a circular manner at a predetermined interval.

  In addition, when the overhang part is formed by press working, the purpose is to reduce the bending resistance in the bending process and make it difficult to cause a weight balance error in the circumferential direction. This was realized by bending the part to be the wall.

[Clamp]
1 to 3 relate to a clamp according to Embodiment 1 of the present invention, (a) is a plan view of a clamp semi-finished product, (b) is a plan view of the clamp, and (c) is a circular clamp semi-finished product. FIG. 2 is a cross-sectional view of main parts taken along line II-II in FIG. 1B, and FIG. 3 is an enlarged cross-sectional view of main parts of the clamp.

  The clamp 1 shown in FIGS. 1B, 2 and 3 is attached to a disk rotation drive device (not shown) such as a 2.5-inch server HDD. The disk rotation driving device rotates and drives a magnetic disk (described later) capable of recording / reproducing information.

  The disk rotation driving device fixedly supports a magnetic disk on a hub (not shown) which is a rotating body that can be rotated by a pressing force in the direction of the rotation axis by the clamp 1.

  The clamp 1 is, for example, formed of a springy stainless steel in a rotating body shape. The hub 1 is a rotating body (not shown) provided with a contact portion 5 on the outer peripheral portion 3 in a circular shape and whose central portion can be driven to rotate. ) Is fastened and fixed to a fitting shaft portion (not shown) by screws (not shown). The abutting portion 5 of the clamp 1 abuts on a magnetic disk 7, which is a disk capable of recording information, and applies a pressing force in the direction of the rotation axis to support the magnetic disk 7 fixedly on the hub. Yes.

  The clamp 1 is formed into a hat cross-sectional shape as a whole, a central portion 9 is formed to be recessed with respect to the outer peripheral portion 3, and a through hole 11 through which a screw is passed is provided in the central portion 9.

  On the outer peripheral portion 3 of the clamp 1, the abutting portion 5 is formed in a circular shape with a curved cross section so as to be oriented in the axial direction.

  A locking wall 15 is formed on the outer peripheral portion 3 so as to protrude from the contact portion 5 to the outer peripheral side. The locking wall 15 is arranged around the outer peripheral portion 3 at a predetermined interval. The interval between the locking walls 15 can be arbitrarily set as long as the C ring 17 can be locked.

  The locking wall 15 supports the C ring 17 which is a balance ring for adjusting the rotational balance by elastically contacting in the radial direction. The diameter D of the C-ring 17 is φ0.65 in this embodiment, although it depends on the size of the HDD.

  The height h from the abutment portion 5, which is the rising dimension of the locking wall 15, is not more than three times the plate thickness of the clamp material (h / t ≦ 3) and is a dimension that allows the C-ring 17 to be locked. That's it. In this embodiment, h = 1.5 mm with respect to the plate thickness t = 0.6 mm of the clamp material. The numerical value less than 3 times the plate thickness of the clamp material is defined by the difficulty in press molding and the height (thickness) dimension constraint in 2.5 inch small HDD.

  The inner peripheral surface 19 of the locking wall 15 is a surface along the rotation axis. An overhang portion 21 is provided on the inner peripheral side of the locking wall 15 to prevent the C-ring 17 from coming off in the direction of the rotation axis. The overhang portion 21 is formed so as to protrude radially inward with respect to the inner peripheral surface 19.

  The overhang portion 21 is set so as to protrude within a range of 0.1 to 0.3 mm with respect to the inner peripheral surface 19 of the locking wall 15 with which the C-ring 17 abuts. = 0.238 mm. The overhang portion 21 has an inclined inner peripheral surface 23 that is inclined with respect to the rotation axis direction. An angle θ formed by the inclined inner peripheral surface 23 with respect to the inner peripheral surface 19 of the locking wall 15 is set in a range of 15 ° to 45 ° with respect to the rotation axis direction. In this embodiment, θ = 32 ° 28. It is set to ′.

  In the clamp 1 having such a configuration, the C ring 17 can be elastically locked to the inner peripheral surface 19 of the locking wall 15. When an impact is input or the like, the overhang portion 21 can prevent the C-ring 17 from coming off from the clamp 1 in the rotation axis direction.

[Center run-out regulation during motor rotation by C-ring]
HDDs generally used as main storage devices used in computers differ in characteristics and quality required depending on the environment in which the computers are used.

  The HDD in which the clamp 1 of the embodiment of the present invention is used is mainly used as a company server, and has a higher level of access speed, reliability, etc. than those used for other uses such as personal use computers and portable devices. Required.

  In particular, the access speed largely depends on the rotational speed of a magnetic disk as a storage medium, and HDDs used for applications other than servers are overwhelmingly those with 7,200 rpm or less, but are used for server applications. The HDD to be rotated has a high rotation speed of 10,000 to 15,000 rpm, so that even when there are multiple accesses, the HDD can react at high speed.

  However, when the motor rotates at a high speed, the influence on the access accuracy due to the center shake at the time of rotation of the motor becomes large. Generally, in a server HDD, it is necessary to regulate the motor rotation shaft runout. A regulation mechanism is also provided.

  In the server HDD in which the clamp 1 of this embodiment is used, this center deflection can be restricted by the C ring 17 called a balance ring.

  That is, when assembling, first, the center runout is measured without attaching the C ring 17.

  The opening side of the C ring 17 is arranged at an appropriate position so that the center deflection is corrected, and the C ring 17 is set on the clamp 1.

  Measure the center run again to confirm that there is no problem.

[Clamp manufacturing method]
A clamp manufacturing method for press-molding a clamp of a disk rotation drive device according to an embodiment of the present invention includes a punching process and a bending process, and the clamp 1 including an overhang portion 21 is formed only by press molding.

  In the punching step, as shown in FIG. 1A, a blank 1A, which is a semi-finished product of the clamp, including the portion 15A that becomes the locking wall 15 of the clamp 1, is punched from the clamp material.

  In the bending step, the overhang portion 21 is formed by bending the portion 15A of the blank 1A to be the locking wall 15.

  In the punching step, the outer peripheral edge 15Aa of the portion 15A to be the locking wall 15 protrudes radially outward in the range of 0.5 to 1.5 mm with respect to the outer peripheral edge 1Aa between the portions 15A. In this embodiment, e = 0.5 mm is set.

  Conventionally, control of rotational runout by the balance ring is performed in a 3.5-inch HDD, and the clamp is formed by cutting using aluminum as a clamp material.

  By the way, until a few years ago, portability was not questioned, so most 3.5-inch HDDs were used.

  However, in recent years, servers have been required to save space, reduce power consumption, and be quiet, and a smaller 2.5-inch HDD that is advantageous for achieving these characteristics is used for servers. Has come to be seen a lot.

  However, even with a 2.5-inch HDD, the center deflection during rotation is required, and a C-ring retaining structure is required for the clamp.

  However, a 2.5-inch HDD is only about 1/2 to 1/3 the thickness of a 3.5-inch HDD, and it is necessary to suppress the total thickness (height) of the clamp. It is necessary to make changes to the clamp used in the HDD. This change is shown below.

  Material change: Clamp material is changed from aluminum to stainless steel. This is because it is necessary to reduce the thickness of the material while maintaining the clamping force, so that the material can withstand high stress.

  Change of processing method: Cutting is changed to press processing. In general, machining increases the cost, so press processing is performed to reduce the cost or suppress the increase in cost.

  Suppression of the total height of the clamp: It is necessary to suppress the dimension h according to the thickness of the 2.5 inch HDD.

  The manufacturing method of the embodiment of the present invention can produce the clamp 1 used for the 2.5-inch HDD in a form satisfying all these requirements.

[Effect of Example]
A clamp 1 according to an embodiment of the present invention is a magnetic disk in which a central portion 9 is fixed to a rotatable drive hub, and an outer peripheral portion 3 is provided with a contact portion 5 in a circular shape, and is mounted on the hub and can record information. In the clamp 1 of the disk rotation driving device that fixedly supports the magnetic disk 7 to the hub by applying the pressing force in the direction of the rotation axis by bringing the contact part 5 into contact with the outer peripheral part 3, the outer peripheral part 3 In addition, a locking wall 15 provided with an overhang portion 21 protruding inward in the radial direction and capable of retaining and locking the C-ring 105 for adjusting the rotational balance in the direction of the rotation axis is arranged in a circular manner at a predetermined interval.

  For this reason, an increase in weight can be suppressed by the interval between the circumferential directions of the locking wall 15 while having the overhang portion 21. Further, since an increase in weight is suppressed, it is possible to make it difficult to cause a weight balance error in the circumferential direction.

  Here, the processing method of the present invention is not limited, but in particular, when the overhang portion 21 is simply formed by press molding, bending resistance in press molding is large, and due to variations in the shape of the overhang portion (convex portion). This tends to cause a weight balance error in the circumferential direction.

  On the other hand, in the shape in which the locking wall 15 having the overhang portion 21 projecting radially inward is arranged in a circular shape at a predetermined interval, the bending resistance of the material due to the press is suppressed, so that the overhang due to the press molding is suppressed. While having the portion 21, it is possible to suppress variations in the shape of the overhang portion (convex portion) and to suppress a weight balance error in the circumferential direction.

  The overhang portion 21 protrudes in the radial direction within a range of 0.1 to 0.3 mm, for example, p = 0.15 mm, with respect to the inner peripheral surface 19 of the locking wall 15 with which the C ring 17 abuts.

  For this reason, it is possible to reliably prevent the C-ring 17 from coming off.

  The overhang portion 21 has an inclined inner peripheral surface 23 that is set to be inclined at an angle of θ = 25 °, for example, in a range of 15 ° to 45 ° with respect to the rotation axis direction.

  For this reason, it is possible to reliably prevent the C-ring 17 from coming off.

  The height h of the locking wall 15 from the abutment portion 5 is not more than three times the plate thickness t of the clamp material and is not less than the dimension enabling the C-ring 17 to be locked.

  For this reason, it is possible to cope with a thin 2.5-inch HDD while enabling press molding, and the C-ring 17 can be reliably locked.

  In the clamp manufacturing method according to the embodiment of the present invention, the blank 1A including the portion 15A that becomes the locking wall 15 of the clamp 1 is punched out of the clamp material, and the portion 15A of the blank 1A that should become the locking wall 15 And forming the overhang portion 21 by bending.

  For this reason, when the overhang portion 21 is formed by pressing, resistance is increased in the case of bending the portion 15A that becomes the locking wall 15 at a predetermined interval as compared with the bending of the circular blank 1B shown in FIG. Therefore, a sufficient overhang amount p can be easily obtained.

For this reason, even under conditions with considerable restrictions on the clamp height, such as 2.5-inch server HDDs, the stainless steel is used as the clamp material to reduce the material thickness and maintain the clamping force. 21 can be pressed, the overhang portion can be easily processed even with a stainless steel clamp material, and the cost can be reduced or the increase in cost can be suppressed.
[Others]
The C-ring 17 can be prevented from coming off and locked to the overhang portion 21 by a structure in which the C-ring 17 is engaged in the attached state, or the inner peripheral surface 19 of the locking wall 15 due to impact of the C-ring 17 or the like. Any of the structures that are engaged when moved along.

(A) is a plan view of the semi-finished clamp product, (b) is a plan view of the clamp, and (c) is a plan view of the circular semi-finished product. Example 1 It is principal part sectional drawing in the II-II arrow line of FIG.1 (b). Example 1 It is a principal part expanded sectional view of a clamp (Example 1). It is a top view of a clamp (reference example). It is a top view of C ring (reference example). It is a principal part expanded sectional view in the IV-IV line of FIG. 4 (reference example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clamp 3 Outer peripheral part 5 Contact part 7 Magnetic disk (disk)
15 Locking wall 19 Inner peripheral surface 21 Overhang portion 23 Inclined inner peripheral surface 105 C-ring (balance ring)

Claims (6)

A central part is fixed to a rotary body that can be driven to rotate, and a contact part is provided around the outer peripheral part, and the contact part is brought into contact with a disk that is mounted on the rotary body and can record information. In the clamp of the disk rotation driving device that fixedly supports the disk on the rotating body by applying a pressing force in the axial direction,
The outer peripheral portion is provided with a locking wall protruding inward in the radial direction with an overhang portion that can be locked to prevent the balance ring for adjusting the rotation balance from coming off in the direction of the rotation axis.
A clamp for a disk rotation drive device. It is a clamp of the disk rotation drive device according to claim 1,
The overhang portion protrudes in the radial direction within a range of 0.1 to 0.3 mm with respect to the inner peripheral surface of the locking wall with which the balance ring abuts.
A clamp for a disk rotation drive device. It is a clamp of the disk rotation drive device according to claim 1 or 2,
The overhang portion has an inclined inner peripheral surface set to be inclined in a range of 15 ° to 45 ° with respect to the rotation axis direction.
A clamp for a disk rotation drive device. It is a clamp of the disk rotation drive device according to any one of claims 1 to 3,
The height of the locking wall from the abutting portion is not more than three times the plate thickness of the clamp material and is not less than a dimension that allows the balance ring to be locked.
A clamp for a disk rotation drive device. A clamp manufacturing method for press-molding a clamp of a disk rotation drive device according to any one of claims 1 to 4,
A punching process of punching a semi-finished clamp product from a clamp material including a portion to be a locking wall of the clamp;
A bending step of forming the overhang portion by bending a portion of the clamp semi-finished product to be the locking wall;
A clamp manufacturing method comprising: The clamp manufacturing method according to claim 5,
The outer peripheral edge of the portion to be the locking wall in the punching process protrudes radially outward in the range of 0.5 to 1.5 mm with respect to the outer peripheral edge between the locking walls.
A clamp for a disk rotation drive device.

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