JPH0550565U - Spindle motor for disk drive - Google Patents

Abstract

(57) [Summary] [Purpose] A disk drive spindle in which a disk clamper is pressed and fitted to a spindle shaft by an assembly jig that uses a screw hole formed through the spindle shaft to fix the disk to a hub by clamping. In the motor, the screw hole is not necessary after assembly and serves as a flow passage for oil mist or the like, which causes a trouble, but the screw hole is closed by a mechanism that is cheaper and requires less labor. [Structure] The screw hole 7b penetratingly formed in the spindle shaft 7 is closed by press-fitting a cylindrical pin 21. Further, as another means, it is possible to adopt a configuration in which a sheet is attached to the end surface of the spindle shaft 7 to close the screw hole 7b. The threaded hole 7b is formed so as to completely clean the threaded hole 7b to remove cutting powder and cutting oil during tapping.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle motor for driving a disc such as a magnetic disc device or an optical disc device, and does not adopt a center clamp method, but uses a screw hole formed through the spindle shaft in advance to assemble the disc clamper for pressing. Measures against dust when fixing the disk to the hub with a tool.

[0002]

[Prior Art]

 The disk drive spindle motor is designed to rotate by fixing the disk to the hub on the rotor side. However, when the center clamp method is not adopted, it is conventionally shown in FIG. 3 or 4 (cross-sectional view of essential parts). Such a configuration is adopted. This motor has an outer rotor circumferentially opposed type configuration.

In each drawing, a core 3 around which a coil 2 is wound and a bearing holder 4 are fixed to a stator base 1, and a flexible flat cable 5 connected to the coil 2 is provided on the stator side. It has a structure derived to the outside. A cover plate 6 is attached to the bottom surface of the stator base 1. On the other hand, on the rotor side, a hub 8 is press-fitted and fixed to the spindle shaft 7, and a magnet 9 is attached to the inner peripheral surface of the outer cylindrical portion of the hub 8 so as to face the core 3 on the stator side. The disc 11 is sandwiched and fixed between the disc clamper 10 and the step surface from the attachment portion to the spindle shaft 7 to the attachment portion of the magnet. Then, on the stator side, two radial bearings 12 are attached by a bearing holder 4 held on the inner peripheral side thereof, and by supporting the spindle shaft 7 on the rotor side through these bearings 12, The entire rotor is rotatably supported.

By the way, as described above, in order to fix the disc 11 with the disc clamper 10 on the stepped surface of the hub 8, the outer peripheral surface of the cylindrical portion of the hub 8 also serving as the shaft press-fitting portion is fitted with a disc clamper. V-shaped groove 8a is formed, and the disc clamper 10 is fitted into the groove 8a so that the disk 11 can be fixed by clamping.

Naturally, the mounting work of the disc 11 is carried out in the process of assembling the spindle motor for driving the disc. At the time of mounting, the screw hole 7a formed in the spindle shaft 7 (in the case of FIG. 3) , 7b (in the case of FIG. 4), the disc clamper 10 is press-fitted onto the spindle shaft 7. That is, after the disk 11 is set on the stepped surface of the hub 8, a plate-shaped jig (not shown) having holes larger than the screw holes 7a and 7b in the central portion is not pressed into the disk clamper. Place a bolt jig (not shown) that has a male screw part that is placed on top of 10 and that is screwed into the screw holes 7a and 7b into the screw holes 7a and 7b through the holes of the plate jig, and The plate-shaped jig is pressed against the disk clamper 10 by the screw-in pressing force generated by rotating the jig, and the disk clamper 10 is press-fitted into the groove 8a of the spindle shaft 7 by the pressing force through the plate-shaped jig. Let When the disk 11 is pinched and fixed to the hub 8 in this manner, the jigs are no longer needed, and the bolt jig and the plate jig are removed.

[0006]

[Problems to be solved by the device]

 Therefore, when mounting the disk 11, it is necessary to form the screw holes 7a and 7b in the spindle shaft 7 in advance, but the method of forming the holes 7a and 7b is as shown in FIG. There is a method of not using (screw hole 7a) and a method of using a through hole as shown in FIG. 4 (needle hole 7b).

The reason why the threaded hole 7a that does not penetrate as shown in FIG. 3 is formed is that when the threaded hole 7b is penetrated as shown in FIG. 4, oil mist or the like generated from the radial bearing 12 is screwed into the threaded hole 7b. This is because they flow to the disk 11 side through and adhere to the surface of the disk 11 to cause a failure such as head crash. However, according to this configuration, since the screw hole 7a is not penetrated, the inside of the hole 7a cannot be sufficiently cleaned after the screw hole 7a is formed. That is, the cutting powder and the cutting oil at the time of tapping remain in the screw hole 7a as they are, which causes a trouble after assembly.

On the other hand, if the threaded hole 7b penetrates as shown in FIG. 4, the threaded hole 7b can be completely cleaned after the formation, but as described above, the oil mist or the like is circulated to cause a failure. Cause of. For this reason, the best conventional measure is to form a threaded hole 7b that penetrates the threaded hole 7b so that the threaded hole 7b can be completely cleaned as shown in FIG. After that, the sealing screw 13 is screw-bonded to solve the problem of cleaning the screw hole 7b and the problem of distribution of oil mist or the like.

However, when the sealing screw 13 is used, the manufacturing cost of the screw 13 becomes high, and since the screw 13 is screwed into the screw hole 7 and the adhesive is filled, the number of steps is increased accordingly. There are drawbacks.

Therefore, the present invention adopts the method of forming the threaded hole 7b penetrating the spindle shaft 7 as in the case of FIG. 4 and FIG. It was created for the purpose of providing a mechanism for a disk drive spindle motor that can be reduced in number and the number of assembly steps.

[0011]

[Means for Solving the Problems]

 A first invention comprises a spindle shaft having a screw hole penetrating in the axial direction and a hub having a disc clamper fitting groove formed on an outer peripheral surface thereof, and the screw shaft is screwed into the screw hole of the spindle shaft. Press the annular disc clamper with an assembly jig to fit the disc clamper into the disc clamper fitting groove of the hub, and thereby fix the disc between the hub and the disc clamper with a confining pressure. The present invention relates to a disk drive spindle motor, wherein a cylindrical pin is press-fitted into a screw hole of the spindle shaft.

A second invention is characterized in that, in a disk drive spindle motor having a disk clamping pressure fixing mechanism similar to the above, a sheet is attached to an end surface of a spindle shaft to close a screw hole. The present invention relates to a spindle motor for driving a disk.

[0013]

[Action]

 In the spindle motor for driving a disk according to the first and second aspects of the present invention, as in the case of the conventional technique (FIGS. 4 and 5), the spindle motor for driving a disk is formed so as to penetrate the spindle shaft in the axial direction in advance. The disc clamper is attached to the spindle shaft by using the screw holes.

In the first invention, the screw hole that serves as a flow passage for oil mist after assembling is formed by pressing a cylindrical pin into the screw hole, and according to the second invention. Then, the sheet is stuck to the end surface of the spindle shaft to be in a closed state.

As a result, since the screw hole penetrates the spindle shaft, cutting powder and cutting oil can be completely removed by completely cleaning after tapping, and the processing is relatively easy and the unit price is also high. It will be possible to block the screw holes with cheap pins and sheets. Also, the closing process can be performed by extremely simple work such as press-fitting pins and sticking sheets, which can simplify the process and reduce the number of steps.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of the essential parts of a disk drive spinddle motor according to a first embodiment (corresponding to the first invention). In the figure, the other elements and mechanisms except for the spindle shaft 7 are the same as those shown in FIGS. 3 to 5 according to the prior art, and the elements having the same reference numerals indicate the same elements. Therefore, the description of the mechanism other than the spindle shaft 7 is omitted here.

The spindle shaft 7 in this embodiment is formed with a screw hole 7b penetrating in the axial direction in the same manner as shown in FIGS. 4 and 5, and the screw hole 7b has a cylindrical pin shape. The feature is that 21 is press-fitted. That is, the spindle shaft 7 is completely cleaned by rubbing it with a brush or the like while tapping the screw hole 7b and flowing a cleaning liquid, and the pin 21 is press-fitted into the screw hole 7b. Here, the pin 21 has a length not more than 1/2 of the total length of the spindle shaft 7 and an outer diameter slightly larger than the inner diameter of the screw hole 7b. One end of the hole 7b is closed. Although the screw hole 7b is formed over the entire length of the spindle shaft 7 in this embodiment, no screw is formed in the press-fitted portion of the pin 21, and the pin 21 is press-fitted into the smooth inner peripheral surface of the hole. You can Further, after the pin 21 is press-fitted, it is in a state of shrinkage as described above, but the material of the pin 21 has a thermal expansion coefficient equal to that of the radial bearing 12 in order to prevent the pin 21 from coming off at the time of temperature rise. Is desirable.

Also, in the mounting process of the disk 11, after the disk 11 is set on the stepped surface of the hub 8, a hole larger than the screw hole 7b is formed in the central portion in the same manner as the above-mentioned conventional technique. Place the plate-shaped jig on the disc clamper 10 that has not been press-fitted, and screw a bolt jig having a male screw part that screws into the screw hole 7b into the screw hole 7b through the hole of the plate-shaped jig. Then, the disc clamper 10 is pressed into the disc clamper fitting groove 8a of the spindle shaft 7 by pressing the disc clamper 10 through the plate jig with the tightening force of the bolt jig. Further, after the disk 11 is fixed to the hub 8 by sandwiching, each jig is unnecessary, and the bolt jig and the plate jig are removed.

In the spindle motor for driving a disk of FIG. 1 assembled through the above steps, the screw hole 7b is completely cleaned, so that the cutting powder and the cutting oil at the time of tapping are completely removed. In addition, since the screw hole 7b is completely blocked by the pin 21, oil mist or the like from the radial bearing 12 side can be prevented from flowing to the disk 11 side through the screw hole 7b. Therefore, when installed in the case of the disk device, it is possible to implement complete dust countermeasures including measures for oil mist inside the device, and it is possible to realize a disk device that does not cause failures such as head crashes. ..

On the other hand, FIG. 2 is a sectional view of the essential parts of a disk drive spindle motor according to a second embodiment (corresponding to the second invention). Also in this embodiment, the components denoted by the same reference numerals as those shown in FIGS. 3 to 5 and FIG. 1 indicate the same elements, and the explanation of the mechanism other than the spindle shaft 7 will be omitted. .. The spindle shaft 7 in this embodiment is formed with the screw hole 7b penetrating in the axial direction similarly to the above-mentioned embodiment, and the double-sided adhesive tape 22 is attached to one end of the screw hole 7b, and The feature is that the polyester film 23 is attached to one adhesive surface. That is, the screw hole 7b is completely closed by a sheet composed of the double-sided adhesive tape 22 and the polyester film 23.

Therefore, the screw hole 7b can be completely cleaned, and the disc clamper 10 is fitted to the hub 8 by a jig using the screw hole 7b to fix the disc 11 by pressure as in the above-described embodiment. In addition, since the screw hole 7b can be completely closed, it is possible to prevent the oil mist or the like from flowing to the disk 11 side.

In particular, in this embodiment, since the extremely simple work of pressing and sticking the polyester film 23 to which the double-sided adhesive tape 22 is stuck to the end surface of the spindle shaft 7, the spindle shaft 7 It is possible to easily seal the screw hole 7b at any stage of the parts before being assembled after cleaning the screw hole 7b, or at the stage before the cover plate 6 is mounted by incorporating the spindle shaft 7 into the device. it can.

[0023]

[Effect of the device]

 The present invention having the above-described configuration has the following effects. According to a first aspect of the present invention, a disc drive for pressing and fitting the disc clamper onto the spindle shaft by an assembling jig that uses a screw hole penetrating in the axial direction of the spindle shaft, and fixing the disc to the hub by clamping. In a spindle motor for a vehicle, a screw hole that is not required after assembly and that acts as a flow passage for oil mist, etc., causing disc crush, etc., is sealed by press fitting a cylindrical pin that is easy to manufacture. Therefore, the manufacturing cost of the motor is reduced and the number of manufacturing steps is reduced. Specifically, the above-mentioned cylindrical pin can be easily manufactured by header processing, can be manufactured at a lower cost than the conventional locking screw, and the screwing required when using the locking screw. This makes it possible to replace the process and the adhesive filling process with only a simple press-fitting process. According to a second aspect of the present invention, in a disk drive spindle motor that uses the same disk fixing method as described above, the screw holes can be closed by simply attaching a sheet to the end surface of the spindle shaft. Similarly, the manufacturing cost and manufacturing man-hours will be reduced, and the screw hole sealing process can be performed with a very simple operation even after the spindle shaft is assembled into the device. In both of the above-mentioned inventions, the screw hole is formed by penetrating the spindle shaft, and since the cleaning after the machining can be completely performed, the trouble caused by the cutting powder or the cutting oil does not occur. Of course, it can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a disk driving spindle motor according to an embodiment corresponding to the first invention.

FIG. 2 is a cross-sectional view of essential parts of a spindle motor for driving a disk according to an embodiment corresponding to the second invention.

FIG. 3 is a sectional view of an essential part of a disk drive spindle motor according to a conventional technique.

FIG. 4 is a sectional view of an essential part of a disk drive spindle motor according to a conventional technique.

FIG. 5 is a cross-sectional view of a main part of a disk driving spindle motor according to a conventional technique.

[Explanation of symbols]

1 ... Stator base, 2 ... Coil, 3 ... Core, 4 ... Bearing holder, 5 ... Flexible flat cable, 6 ... Cover plate, 7 ... Spindle shaft, 7b ... Screw hole, 8 ...
Hub, 8a ... Disc clamper fitting groove, 9 ... Magnet, 10 ... Disc clamper, 11 ... Disc, 12 ... Radial bearing, 21 ... Pin, 22, 23 ... Sheet (double-sided adhesive tape, polyester film).

Claims (2)

[Scope of utility model registration request] 1. An assembly comprising a spindle shaft having a threaded hole penetrating in an axial direction formed therein and a hub having a disc clamper fitting groove formed on an outer peripheral surface thereof, the assembly being screwed into the threaded hole of the spindle shaft. A disc drive for fixing the disc between the hub and the disc clamper by pressing the annular disc clamper with a jig and fitting the disc clamper in the disc clamper fitting groove of the hub. A spindle motor for a disk drive, wherein a cylindrical pin is press-fitted into a screw hole of the spindle shaft. 2. An assembly comprising a spindle shaft having an axially threaded hole formed therein and a hub having an outer peripheral surface formed with a disk clamper fitting groove, and being screwed into the threaded hole of the spindle shaft. A disc drive for fixing the disc between the hub and the disc clamper by pressing the annular disc clamper with a jig and fitting the disc clamper in the disc clamper fitting groove of the hub. A spindle motor for disk drive, wherein a sheet is attached to an end surface of the spindle shaft to close a screw hole.