JPH03261359A - Motor for disk driving equipment - Google Patents

Abstract

PURPOSE:To improve accuracy in positioning a motor by securing an outer surface of a bearing to a cylinder section through a spacer collar when a dimensional accuracy between a reference surface for mounting media and a reference surface of the motor for mounting it on an equipment, is maintained. CONSTITUTION:A reference surface 35 of a lower jig 31 and a spring mounting surface 36 are provided on the lower jig 31, and a dimension between the reference surface 35 and the mounting surface 36 is made equal to a dimension between a mounting reference surface 13 of a motor 1 to an equipment and a reference surface 18 for mounting media. A reference surface 38 of an upper jig 32 and a spring mounting surface 39 are provided on the upper jig 32. When a shaft 6 is positioned and secured to a bracket 3, the motor 1 is positioned between the upper jig 32 and the lower jig 31 with the outer surface of bearings 15A and 15B not being secured to a spacer collar 16. Then, the outer surface of the upper and lower bearings 15A and 15B is affixed to a cylinder section through the spacer collar 16.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a motor for a disk drive device installed to rotate a magnetic disk in, for example, a floppy disk drive device or a hard disk drive device as a magnetic storage device. Regarding.

<Prior Art> In recent years, magnetic disk drives such as floppy disk drives and hard disk drives have been used as external storage devices for word processors and personal computers. This magnetic disk drive device rotates a magnetic disk using a spindle system, and writes and reads information onto the magnetic disk using a magnetic head.

The spindle system is also provided with a disk drive motor, ie, a spindle motor, which is attached to the base frame.

FIG. 3 shows an example of a conventional motor for a disk drive device.

This motor 41 has a shaft 43 to which a hub 42 is rotatably attached, and a cylindrical portion 45 provided with a through hole 44 into which the shaft 43 is inserted. A bracket 46 is provided with a mounting reference surface 53 (as shown), and a steel ball 47 is attached to the bracket 46.
The inner ring 47b has an inner ring 47b and an outer ring 47C that are rotatably connected to each other with the inner ring 47a in between.
A pair of upper and lower bearings 47A and 47B whose outer rings are fixed to the inner surface of the cylindrical portion 45, a rotor magnet 49 which is fixed to the inner surface of the hub 42 via the rotor frame 48, and It is comprised of a stator core 50 fixed to the outer surface facing the rotor magnet 49, a winding 51 wound around the stator core 50, and the like. In addition, the hub 42 has a flange 42a on the outer periphery, and a media attachment reference surface 52 is formed on the flange 42a. Also, bearing 47A and bearing 47
A preload is applied between it and B by a preload spring 54. Further, within the cylindrical portion 45, above the bearing 47A, there are two
two seal yokes 56 made of ferromagnetic material, and a seal magnet 57 disposed between the two seal yokes 56.
and a magnetic fluid 58 injected into the gap between the shaft 43 and each seal yoke 56.
5 is provided. And this magnetic fluid seal 55
This prevents dust from entering through the upper bearing 47A and scattering of grease from the upper and lower bearings 47A and 47B.

The motor 41 configured in this manner is positioned so that the mounting reference surface 53 provided on the bracket 46 is in contact with the mounting reference surface on the device side (not shown), and the mounting hole 53 provided on the bracket 46 is positioned in contact with the mounting reference surface 53 on the device side (not shown). It is attached to the disk drive device via a screw (not shown) inserted into 59. Then, when a drive current is applied to the winding 51 via the control circuit on the mounting circuit board 60 disposed on the upper surface of the bracket 46, the hub 2 rotates together with the shaft 43, and at this time, the media attachment reference surface 52 If there is a magnetic disk (not shown) disposed above, it will rotate together with this magnetic disk.

Also, this kind of magnetic disk drive! The main requirements for the motor 41 in commercial applications include high reliability, good mechanical precision and stability, and low noise.

In order to meet these demands, the hub 42 and the bracket 46 are made of aluminum to eliminate track position shift due to temperature changes, or various improvements are made to the bearing structure.

One way to improve the bearing structure is to attach a preload spring 54 to the upper and lower bearings 47 as shown in FIG.
In addition to applying preload between bearings 47A and 47B to accurately position the shaft 43 in the radial and axial directions and suppressing vibration of the shaft 43, it is also possible to increase the rigidity of the bearings 47A and 47B, or to use steel balls. There are methods such as No. 47a that suppress rotational slippage, revolution slippage, and rotational slippage of rolling elements.

Problems to be solved by this invention> However, in the positioning method using the preload spring 54, the amount of preload is kept almost constant even if the bearings 47A, 47B change due to temperature changes, but the preload is not applied. As a result, each bearing 47A, 47B has an inner ring 47b.
A difference width δ occurs between the outer ring 47c and the outer ring 47c. Further, this difference width δ is not constant and varies depending on the bearings 47A and 47B, and this variation affects the dimension between the mounting reference surface 53 of the motor 41 and the media mounting reference surface 52. In order to ensure dimensional accuracy between the mounting reference surface 53 of the motor 41 and the media mounting reference surface 52, as shown in FIG. A shim 61 is interposed in between for adjustment. Furthermore, as an adjustment method other than this, after assembly, the media attachment reference surface 52
Methods such as grinding have also been adopted.

However, the method of interposing the shim 61 during assembly for adjustment has a problem in that the shim 61 also has tolerances and sufficient dimensional accuracy cannot be ensured.

On the other hand, with the method of grinding the media attachment reference surface 52 after assembly, it is easy for ground dust to enter the disk enclosure of a magnetic disk drive, which is particularly sensitive to dust, and it takes time and effort to clean this dust. There was a problem.

Furthermore, today there is a demand for word processors and personal computers that are smaller and thinner, and along with this, there is also a demand for smaller and thinner magnetic disk drives and the like. Therefore, it is expected that conventional adjustment methods will not be sufficient to satisfy these demands.

The present invention has been made in view of the above problems, and its purpose is to stabilize the mechanical precision and cleanliness of a motor for a disk drive device, and to provide a disk drive that can be made thinner and have improved reliability. The purpose of the present invention is to provide a motor for a device.

<Means for Solving the Problems> In order to achieve the above object, a motor for a disk drive device according to the present invention has a media attachment reference surface provided on a hub attached to a rotating shaft side and a fixed side fixed to the device. A spacer collar is provided for fixing the outer ring of the bearing within the cylindrical portion while ensuring dimensional accuracy between it and a mounting reference surface provided on the bracket, and the materials of the shaft and the spacer collar are selected based on the i tension coefficient of the bearing. It is configured according to the

According to this configuration, the outer ring of the bearing is fixed to the cylindrical part via the spacer collar while maintaining the dimensional accuracy between the media mounting reference surface and the device mounting reference surface, which eliminates the conventional structure. There is no need for shim adjustments such as. Also,
There is no need for grinding after assembly as in conventional structures.

Furthermore, since the materials of the shaft and spacer collar are matched to the expansion coefficient of each bearing, the amount of preload can be kept almost constant even if temperature changes occur.

Furthermore, since a spacer collar is provided to maintain rotation of the shaft, it is also possible to use the motor bracket as the base frame of the disk drive device.

<Example> Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 shows an embodiment of a motor for a disk drive device according to the present invention.

In the figure, this motor 1 mainly includes a bracket 3 on which a stator element 2 is disposed, a hub 5 on which a rotor element 4 is disposed, and a shaft 6 on which the hub 5 is attached so as to be rotatable as a unit. It is made up of.

More specifically, the bracket 3 has a cylindrical portion 8 extending upward from the upper surface 3a, which is provided with a through hole 7, into which the shaft 6 is inserted, approximately at the center thereof. The outer periphery of the cylindrical portion 8 is formed so that the outer diameter of the upper side is smaller from the middle in the length direction, and a step 8a is provided in the middle. Then, the stator element 2 is attached in a state where it is positioned on this step 8a. Note that this stator element 2 is constructed by laminating a plurality of plate-shaped cores to form a cylindrical portion 8.
The stator core is non-rotatably attached to the outer periphery of a small diameter portion of the stator core, and a winding 10 is wound around the stator core 9. Further, a recess 11 is formed in the upper surface 3a of the bracket 3 so as to surround the outside of the cylindrical portion 8, and an annular groove 12 whose center is the same as that of the cylindrical portion 8 is provided within the recess 11. .

On the other hand, a mounting reference surface 13 for the device (disk drive device) is provided on the outer circumferential portion of the lower surface 3b side of the bracket 3, and the upper and lower surfaces 3a, 3b are located correspondingly to this mounting reference surface 13. A plurality of mounting holes 14 are provided in a scattered manner.

Next, the shaft 6 has a large diameter portion 6a formed at an outer peripheral portion midway in the length direction. The lower side of the large diameter portion 6a is inserted into the cylindrical portion 8, and is rotatably held within the cylindrical portion 8 via a pair of upper and lower bearings 15A, 15B and a spacer collar 16. The pair of upper and lower bearings 15A and 15B each have a steel ball 15a as a rolling element, and an inner ring 15b and an outer ring 15c that are rotatably connected to each other with the steel ball 15a in between. is fixed to the shaft 6, and the outer ring 15c is fixed to the cylindrical part 8 side via a spacer collar 16 that is fixed inside the cylindrical part 8. In addition, in this embodiment, even if the temperature changes, the upper and lower bearings 15A,
The materials of the shaft 6 and the spacer collar 16 are matched to the expansion coefficients of the bearings 15A and 15B so that the amount of preload between the bearings 15B can be kept approximately constant.

On the other hand, above the large diameter portion 6a of the shaft 6, the hub 5, which is formed in a substantially drag cup shape, is attached with the cup shape upside down. This hub 5 is attached to the bracket 3 side integrally with the shaft 6, and is attached so as to completely cover the outside of the cylindrical portion 8 to which the stator element 2 is attached in a non-contact state. Further, the hub 5 is integrally provided with a flange 17 on the outer periphery of the lower end, and a media attachment reference surface 18 for positioning a magnetic disk (not shown) is integrally formed on the upper surface of the flange 17. . In addition, on the lower surface side of the flange 17, in correspondence with the arms 12 provided on the hub 5, an annular wall 19 is inserted downward into the arms 12 in a non-contact state and forms a labyrinth structure together with the grooves 12. It is installed in one piece.

On the other hand, a rotor element 4 is attached to the inside of the hub 5 so as to correspond to the stator element 2. The rotor element 4 includes a cylindrical rotor frame 20 fixed to the inner surface of the hub 5 and a cylindrical rotor magnet 21 fixed to the inner surface of the rotor frame 20. The hub 5 configured in this way has upper and lower bearings 15
A.

15B and spacer collar 16 to one end of the shaft 6 which is rotatably attached to the cylindrical part 8, it completely covers the outside of the cylindrical part 8 to which the stator element 2 is attached in a non-contact state. is arranged, thereby stator element 2
and the rotor element 4 are opposed to each other and can function as a motor. Also, in this assembled state? The annular wall 19 is inserted into the '1l12.

In this motor 1, when a driving current is applied to the winding 10, the hub 5 rotates together with the shaft 6. Further, during this rotation, the labyrinth structure created by the engagement between the shaft 12 and the annular wall 19 prevents dust from entering the hub 5, and the upper and lower bearings 15A
, 15B can be prevented from scattering.

Next, FIG. 2 shows an assembly jig for positioning and fixing the shaft 6 of the motor 1 with respect to the bracket 5, together with the motor 1' while it is being fixed. Therefore,
A method for positioning and fixing the shaft 6 to the bracket 5 using FIG. 2 will be explained next.6 The assembly jig 30 shown in FIG.
It also includes a first spring 33, a second spring 34, and the like. Among these, the lower jig 31 has a reference surface 35 and the dimensions of the first spring taking amount formed by the dimensions between the device attachment reference surface 13 and the media attachment reference surface 18 on the motor 1 side. . On the other hand, the upper jig 32 has
A reference surface 38 on the upper jig side and a second spring mounting surface 39 are provided.

When positioning and fixing the shaft 6 to the bracket 3, the second outer ring 15c of the bearings 15A and 15B is not yet fixed to the spacer collar 16.
As shown in the figure, the motor 1 is placed between the upper jig 32 and the lower jig 31. That is, the mounting reference surface 13 of the bracket 3 is connected to the reference surface 38 on the upper jig 32 side by the first spring 33.
At the same time, the reaction force of the second spring 34 pushes the shaft 6 in the length direction, and a preload is applied between the inner ring 15b and outer ring 15c of the upper and lower bearings 15A and 15B. In this state, the media attachment reference surface 18 is brought into contact with the first spring attachment surface 36. As a result, the mounting surface 36 is provided in a state where the upper and lower bearings 15A and 15B are each preloaded, and the reference surface 35 and the mounting surface 3 are provided.
6 and the mounting reference surface 13 and media mounting reference surface 18
Next, the outer rings 15c of the upper and lower bearings 15A and 15B are adhesively fixed to the cylindrical portion 8 via the spacer collar 16 in this state. Then, the shaft 6 is attached to the bracket 3 while maintaining this dimensional accuracy.

Therefore, according to this structure, there is no need to use shims to adjust the position between the bracket and the shaft, or to perform grinding after assembly, unlike conventional motors for disk drive devices.

Although the present invention has been explained using the above embodiment, it is of course not limited to the structure of this embodiment, and various changes in design may be made without departing from the gist of the present invention. For example, in the above embodiment, a structure applied to a brushless type motor is disclosed, but it may also be applied to a brushed motor. Further, the present invention is not limited to drive devices using magnetic disks, and can be applied to a wide variety of general disk drive devices.

<Effects of the Invention> As explained above, according to the motor for a disk drive device according to the present invention, the outer ring of the bearing can be mounted while maintaining the dimensional accuracy between the metal mounting reference surface and the device mounting reference surface. It is fixed to the cylindrical part via the spacer collar, so
There is no need for shim adjustment as in the conventional structure, and the positioning accuracy between the media attachment reference surface and the device attachment reference surface can be improved. This makes it possible to equalize the performance of each motor. Further, unlike conventional structures, there is no need for bleach machining after assembly, so the cleanliness of the motor can be maintained at a desired level by simply cleaning the individual parts.

Furthermore, since the materials of the shaft and spacer collar are matched to the expansion coefficient of each bearing, the amount of preload can be kept almost constant even when temperature changes occur, making it possible to reduce the thickness and improve reliability.

In addition, since a spacer collar is provided to maintain the rotation of the shaft, the motor bracket can be shared with the base frame of the disk drive unit, which further improves the positional accuracy of the media mounting reference surface. , it is possible to reduce the number of parts on the tisf drive system summer side and lower costs.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional side view showing one embodiment of a motor for a disk drive device according to the present invention, and FIG. 2 is a schematic longitudinal cross-sectional view showing an assembly jig for positioning and fixing the shaft to a bracket in the same motor together with the same motor. Side View FIG. 3 is a longitudinal sectional side view showing an example of a conventional motor for a disk drive device. DESCRIPTION OF SYMBOLS 1...Motor, 2...Stator element, 3'...Bracket, 4...Rotor element, 5...Hub, 6...
Shaft, 7... Through hole, 8... Cylindrical portion, 13... Mounting reference surface to device, 15A... Upper bearing, 15B... Lower bearing, 15a... Steel ball, 15b... - Inner ring, 15c... Outer ring, 16... Spacer collar 18... Media mounting reference surface. 15Δ Longitudinal side view showing one embodiment of the present invention FIG. 1 1...Motor 2...Stator element 3...Bracket 4...Rotor element 5...Hub 6...Shaft 7 ...Through hole 8...Cylinder] 3...Mounting reference surface 15A, 15B...Bearing 16...Spacer collar 18...Media mounting reference surface

Claims (1)

[Scope of Claims] A shaft to which a hub having a media attachment reference surface is integrally rotatably attached, a bracket having a cylindrical portion having a through hole through which the shaft is penetrated, and a mounting reference surface to the device; a pair of upper and lower bearings each having an inner ring and an outer ring rotatably connected, the inner ring being fixed to the shaft and the outer ring being fixed within the cylindrical portion; and a rotor element disposed on the hub. and a stator element disposed on the bracket, the motor for a disk drive device comprising: a stator element disposed on the bracket; and a stator element disposed on the bracket. A motor for a disk drive device, comprising a spacer collar for fixing each of the outer rings of a bearing within the cylindrical portion, and materials of the shaft and the spacer collar are configured to match an expansion coefficient of the bearing.