JPH0865949A - Motor - Google Patents

Abstract

PURPOSE: To prevent the adverse influence to life deterioration and characteristics by solving the leakage of lubricant in a bearing, scattering of the lubricant from the bearing due to a pressure difference between the interior and the exterior of a motor, and generation of a damping effect due to the mixed air between a radial bearing and a thrust bearing in a dynamic pressure fluid bearing used for the motor. CONSTITUTION: A through hole 218 is provided at the center of the spiral groove 106 of a thrust receiving plate 105, sealed by a locking pin, and lubricant is fully filled even in a gap. Accordingly, a damping effect due to the air mixed between a radial bearing and a thrust bearing does not occur. Further, an O-ring 215 is so embedded as to seal between a bearing sleeve and an upper cover 217, and lubricant also fills up the sealed gap, and hence adverse influence does not act on life deterioration and characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a motor having a hydrodynamic bearing.

[0002]

2. Description of the Related Art In recent years, motors have been required to be small and thin, and to be required to have high-speed rotation, rotational runout accuracy, and noise reduction. The used motor is being used.

A conventional motor will be described below with reference to the drawings. FIG. 3 shows a conventional polygon mirror driving device using a hydrodynamic bearing. In FIG. 3, a shaft 101 having a herringbone-shaped shallow groove 102 is rotatably fitted in inner diameter holes of bearing sleeves 103 and 104, and a thrust receiving plate 105 is arranged at a lower end portion of the bearing sleeve 104. The bearing sleeve 104 is fixed to the bracket 108. A spiral groove 106 is engraved on the thrust receiving plate 105, and a groove hole 107 is formed in the central portion. Bearing sleeve 1
03 is fixed to the cover 109. A flange 110 is fixed to the shaft 101, a polygon mirror 111 is fixed to the upper part of the flange 110, and a driving magnet 112 is fixed to the lower part.
Has been fixed. The stator core 1 fixed to the bracket 108 is located at a position facing the driving magnet 112.
13 is installed, and further, a Hall element 114 for detecting a position during rotation is installed.

The rotating body having such a structure rotates without contact due to the dynamic pressure of the lubricant.

[0005]

However, in the above-mentioned conventional structure, the lubricant present in the upper bearing sleeve is mainly retained only by the surface tension of the radial gap between the shaft and the bearing sleeve, so that the lubricant is retained for a long period of time. If left for a long time, the lubricant will gradually begin to escape,
Further, even when a pressure difference occurs between the pressure generated inside the motor and the external pressure during rotation, the lubricant is pushed out from the bearing and escapes, thus shortening the motor life.

Further, if the thrust bearing plate is fixed after inserting the rotary shaft into the lower bearing sleeve, air will be mixed into the hydrodynamic bearing portion, and the rotary shaft will be inserted after fixing the thrust bearing plate to the bearing sleeve in advance. If this is attempted, there is a problem that the air mixed during insertion causes a damping effect, which affects the life and characteristics of the bearing.

The present invention solves the above-mentioned conventional problems, and makes it possible to sufficiently retain the lubricant in the shaft and the bearing sleeve. It is another object of the present invention to provide a motor having a hydrodynamic bearing which can prevent air from being mixed when the shaft is inserted into the bearing sleeve.

[0008]

To achieve this object, the motor of the present invention is provided with a sealing member at the open end of the upper sleeve, and a gap between the shaft end and the sealing member is filled with a lubricant. In addition, the lubricant is injected into the through hole at the center of the thrust receiving plate and is sealed by the sealing member.

[0009]

With this structure, the gap between the shaft end and the sealing member and the gap between the shaft end and the thrust receiving plate are filled with the lubricant, so that there is no pressure difference between the inside and outside of the motor. Without pushing the lubricant out of the bearing, the retaining force of the lubricant acting on the gap also acts on the radial gap between the shaft and the bearing sleeve to increase the surface tension and prevent the lubricant from flowing out. Since there is no air between the bearing and the thrust bearing, there is no damping effect due to the mixed air, and there is no adverse effect on life deterioration or characteristics.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

The same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. 1 is different from FIG. 3 in that the bearing sleeve 103 has a ring-shaped groove 216 for inserting the O-ring 215, and the O-ring 215 is embedded so as to seal between the bearing sleeve 103 and the upper lid 217. Further, the sealed gap is also filled with the lubricant. Further, a through hole 218 is provided in the center of the spiral groove 106 of the thrust receiving plate 105, and is sealed by a stop pin 219.

The operation of the motor constructed as described above is the same as that of the conventional example, and the description thereof is omitted.

Here, by providing an upper lid on the upper sleeve and allowing the lubricant to exist also in the gap between the rotating shaft and the upper lid, the force for holding the lubricant in this gap is generated between the inner circumference of the bearing sleeve and the outer circumference of the rotating shaft. Since the holding force of the lubricant, so-called surface tension, is increased, it is possible to prevent the lubricant from flowing out.

Further, by providing the through hole in the thrust receiving plate, the air in the lubricant in the bearing sleeve, the rotating shaft and the thrust receiving plate can be removed, and then the through hole is sealed by the stop pin to prevent the lubricant. It is possible to prevent the outflow of water and to prevent a decrease in dynamic pressure. Moreover, if the length of the stop pin is set shorter than the length of the through hole of the thrust receiving plate, a recess is formed in the center of the spiral groove, and this recess should accommodate wear powder and dust generated by the rotation of the rotating body. You can

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

The same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 2, the difference from the first embodiment is that a female screw portion 318 is formed in the through hole and a male screw portion 319 is formed on the outer peripheral portion of the stop pin. The description is omitted because it is the same.

As described above, by screwing the through hole of the thrust receiving plate with a screw, the sealing after the air in the lubricant in the bearing sleeve, the rotary shaft and the thrust receiving plate is removed is simplified. be able to.

In the first and second embodiments, if the upper lid for sealing the upper sleeve is also used by using a fixing pin or a fixing screw as in the case of sealing the lower sleeve, the mixed air is mixed. Can be completely removed, which is more effective.

Furthermore, in the first and second embodiments, further effects can be expected if an adhesive is used together for sealing.

Although an example of the inner rotor type structure has been shown, there is no particular problem with an outer rotor type or a plane facing type.

Although the sleeve is separated into the upper side and the lower side and both ends of the shaft are supported, the upper and lower sleeves may be integrated so that only one side of the shaft is supported.

[0023]

As described above, according to the present invention, the lubricant is also injected into the through hole provided in the central portion of the thrust receiving plate, and the sealing member is fitted and fixed or the through hole and the sealing member are provided with the screw portion. Since the air is not present between the radial bearing and the thrust bearing by installing and fastening together or using adhesive filling, there is no damping effect due to the mixed air, and there is no adverse effect on life deterioration or characteristics. . further,
Since the dust collecting hole can be configured by a hole generated by making the insertion length of the sealing member shorter than the through hole length, it is not easily affected by dust.

In a motor configuration in which the sleeve is divided into two parts, the upper sleeve open end is filled with a lubricant and sealed with a sealing member, or an elastic sealing material such as an O-ring is also sealed together, or A through hole is provided in the center of the sealing member to inject a lubricant, and a second sealing member is fitted and fixed, or a through hole and a screw portion are provided in the sealing member for fastening fixation or adhesive filling. As a result, the surface tension of the lubricant can be increased to prevent the lubricant from flowing out, and since there is no pressure difference between the inside and outside of the motor, there is no need to push the lubricant out of the bearing, resulting in deterioration of the service life. It is possible to realize an excellent motor that does not adversely affect the characteristics.

[Brief description of drawings]

FIG. 1A is a sectional view of a motor according to a first embodiment of the present invention. FIG. 1B is an enlarged top view of a bearing thrust bearing plate with a spiral groove. FIG. 1C is an enlarged sectional view of a bearing thrust bearing plate with a spiral groove.

2A is a sectional view of a motor according to a second embodiment of the present invention. FIG. 2B is an enlarged top view of a bearing thrust bearing plate with a spiral groove. FIG. 2C is an enlarged sectional view of a bearing thrust bearing plate with a spiral groove.

FIG. 3A is a sectional view of a conventional motor. FIG. 3B is an enlarged top view of a bearing thrust bearing plate with a spiral groove. FIG. 3C is an enlarged sectional view of a bearing thrust bearing plate with a spiral groove.

[Explanation of symbols]

 Reference Signs List 101 rotating shaft 102 herringbone shallow groove 103, 104 bearing sleeve 105 thrust receiving plate 106 spiral groove 108 bracket 109 cover 110 flange 111 polygon mirror 112 driving magnet 113 stator core 114 Hall element 215 O-ring 216 ring-shaped groove 217 upper lid 218 Through hole 219 Lock pin 318 Female thread 319 Male thread

Claims (12)

[Claims] 1. A shaft, a sleeve for supporting the shaft, a thrust receiving plate provided at an end of the sleeve so as to face the end of the shaft, and an outer circumference of the shaft or an inner circumference of the sleeve. A radial dynamic fluid bearing is formed by providing a spiral groove or a herringbone groove on at least one side, and a thrust dynamic fluid bearing is also provided by providing a spiral groove or a herringbone groove on at least one of the end portion of the shaft or the thrust receiving plate. And a lubricant is injected into the hydrodynamic bearing, a through hole is provided in the center of the thrust receiving plate, the lubricant is injected into the through hole, and the through hole is sealed. A motor having a stop member fitted and fixed. 2. The motor according to claim 1, wherein the through hole and the sealing member are provided with screw portions and fastened. 3. The motor according to claim 1, wherein the gap between the sealing member inserted into the through hole and the through hole is filled with an adhesive. 4. The motor according to claim 1, wherein the insertion length of the sealing member is shorter than the through hole length. 5. A rotor assembly having a rotating shaft, a cup-shaped bracket, a cover attached to the open end of the bracket so as to enclose the rotor assembly, and a rotating member provided in the center of the closed end side of the bracket. A sleeve supporting the shaft, a thrust receiving plate provided at one end of the sleeve so as to face the end of the rotary shaft, and a spiral groove or at least one of the outer circumference of the rotary shaft or the inner circumference of the sleeve. Forming a radial dynamic fluid bearing by providing a herringbone groove, and forming a thrust dynamic fluid bearing by providing a spiral groove or a herringbone groove on at least one of the end portion of the rotating shaft or the thrust receiving plate, and A sleeve that supports the rotating shaft also in the center of the cover, and an outer periphery of the rotating shaft or an inner peripheral portion of the sleeve is reduced. A spiral groove or a herringbone groove is provided on one side to form a radial dynamic pressure fluid bearing, and in a configuration in which a lubricant is injected into the dynamic pressure fluid bearing, a sealing member is provided at the sleeve open end arranged in the cover. And a gap between the end of the rotary shaft and the sealing member is filled with the lubricant. 6. The motor according to claim 5, wherein the sleeve and the bracket or the cover are integrally formed of the same material. 7. The motor according to claim 5, wherein the sealing member is fixed to the sleeve via an elastic sealing material having a ring shape, a column shape, or a prism shape. 8. The motor according to claim 5, wherein the sealing member is fixed to the sleeve via an O-ring. 9. The motor according to claim 5, wherein the gap between the sealing member fixed to the sleeve and the sleeve is filled with an adhesive. 10. The sealing member is provided with a through hole, a lubricant is injected also into the through hole, and a second sealing member is fitted and fixed in the through hole. The motor according to claim 6 or claim 7 or claim 8 or claim 9. 11. The motor according to claim 10, wherein the through hole and the second sealing member are provided with a screw portion and fastened. 12. The motor according to claim 10, wherein the gap between the second sealing member inserted into the through hole and the through hole is filled with an adhesive.