JP3125588B2 - motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, demands for high-speed rotation, rotational runout accuracy, and low noise have become stronger along with demands for smaller and thinner motors. Accordingly, hydrodynamic fluid bearings having better performance than ball bearings have been required. The used motor is being used.

[0003] A conventional motor will be described below with reference to the drawings. FIG. 3 shows a polygon mirror driving device using a conventional hydrodynamic bearing. In FIG. 3, a shaft 101 having a herringbone-shaped shallow groove 102 is rotatably fitted to the inner diameter holes of the bearing sleeves 103 and 104, and a thrust receiving plate 105 is arranged at the lower end of the bearing sleeve 104. At the same time, 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 107 is provided at the center. 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 are provided, and a Hall element 114 for detecting a position during rotation is further provided.

[0004] The rotating body thus configured rotates in a non-contact manner by the dynamic pressure of the lubricant.

[0005]

However, in the above-mentioned conventional construction, the lubricant present in the upper bearing sleeve is mainly held only by the surface tension of the radial gap between the shaft and the bearing sleeve. If left for a long time, the lubricant will gradually begin to escape,
Also, when a pressure difference is generated between the pressure generated inside the motor and the external pressure during rotation, the lubricant is pushed out of the bearing and comes off, thereby shortening the motor life.

Further, if the thrust receiving plate is fixed after the rotary shaft is inserted into the lower bearing sleeve, air enters the hydrodynamic bearing portion, and the rotary shaft is inserted after the thrust receiving plate is fixed to the bearing sleeve in advance. If this is attempted, there is a problem that a damping effect occurs due to air mixed in at the time of insertion, which affects the life and characteristics of the bearing.

[0007] The present invention solves the above-mentioned conventional problems, and enables a lubricant to be sufficiently retained in a shaft and a bearing sleeve. It is another object of the present invention to provide a motor having a hydrodynamic bearing capable of preventing air from being mixed when the shaft is inserted into the bearing sleeve.

[0008]

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

[0009]

With this configuration, 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 the outside of the motor. Without pushing out the lubricant from the bearing, the lubricant holding force acting on the gap also acts on the radial gap between the shaft and the bearing sleeve, increasing the surface tension and preventing the lubricant from flowing out. Since there is no air between the bearing and the thrust bearing, there is no occurrence of a damping effect due to the mixed air, and there is no adverse effect on the life and the 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 in the conventional example are denoted by the same reference numerals, and description thereof is omitted. 1 is different from FIG. 3 in that a ring-shaped groove 216 is set in the bearing sleeve 103 for inserting an 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 a lubricant. Further, a through hole 218 is provided at the center of the spiral groove 106 of the thrust receiving plate 105, and the thrust receiving plate 105 is sealed by a stopper pin 219.

The description of the operation of the motor constructed as described above is the same as that of the conventional example, and therefore will not be repeated.

[0013] Here, the upper sleeve is provided with an upper lid, and the lubricant is also present in the gap between the rotary shaft and the upper lid. In order to increase the retaining force of the lubricant, that is, the so-called surface tension, it is possible to prevent the lubricant from flowing out.

Further, by providing a through hole in the thrust receiving plate, air in the bearing sleeve, the rotating shaft and the lubricant in the thrust receiving plate can be evacuated. Outflow and a decrease in dynamic pressure can be prevented. In addition, if the length of the retaining pin is set shorter than the length of the through hole of the thrust receiving plate, a concave portion is formed in the center portion of the spiral groove, and the concave portion accommodates abrasion powder and dust generated by rotation of the rotating body. Can be.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

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

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

In the first and second embodiments, when the upper cover for sealing the upper sleeve is also used together with the fixing pin or the set screw in the same manner as the sealing for the lower sleeve, mixed air can be obtained. Can be completely removed, so that the effect is improved.

Further, in the first and second embodiments, further effects can be expected if an adhesive is used at the time of sealing.

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

In addition, although an example has been shown in which the sleeve is separated into upper and lower sides and both ends of the shaft are supported, a structure in which the upper and lower sleeves are integrated and only one side of the shaft is supported may be used.

[0023]

As described above, according to the present invention, the lubricant is injected into the through hole provided at the center of the thrust receiving plate, and the sealing member is fitted and fixed, or the screw portion is formed between the through hole and the sealing member. By providing and fastening and fixing or filling with adhesive, there is no air between the radial bearing and the thrust bearing, so there is no occurrence of a damping effect due to the mixed air, and there is no adverse effect on life or characteristics . further,
Since the hole generated by making the insertion length of the sealing member shorter than the length of the through hole can constitute the dust collecting hole, it is less affected by dust.

In a motor configuration in which the sleeve is divided into two upper and lower portions, the open end of the upper sleeve is filled with a lubricant and sealed with a sealing member, or an elastic sealing material such as an O-ring is sealed together, or A through hole is provided in the center of the sealing member to inject lubricant, and the second sealing member is fitted and fixed, or a screw portion is provided in the through hole and the sealing member, and fastening and fixing or filling with an adhesive is used together. As a result, it is possible to prevent the lubricant from flowing out because the surface tension of the lubricant is increased, and since there is no pressure difference between the inside and the outside of the motor, the lubricant is not pushed out of the bearing, so that the life is shortened and the life is shortened. An excellent motor that does not adversely affect characteristics can be realized.

[Brief description of the drawings]

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 receiving plate with a spiral groove. FIG. 1C is an enlarged sectional view of a bearing thrust receiving 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 receiving plate with a spiral groove. FIG. 2C is an enlarged sectional view of a bearing thrust receiving plate with a spiral groove.

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]

 101 rotating shaft 102 herringbone-shaped 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 top cover 218 Through hole 219 Lock pin 318 Female thread 319 Male thread

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-4428 (JP, A) JP-A-59-32336 (JP, U) JP-A-59-23271 (JP, U) JP-A-62 154766 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 7/08

Claims (12)

(57) [Claims] 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 periphery of the shaft or an inner periphery of the sleeve. A radial hydrodynamic bearing is formed by providing a spiral groove or a herringbone groove on at least one of the shafts, and a spiral groove or a herringbone groove is provided on at least one of the end 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, a lubricant is injected into the through-hole, and the through-hole is further sealed. A motor, wherein a stop member is fitted and fixed. 2. The motor according to claim 1, wherein the through-hole and the sealing member are fastened by providing a screw portion. 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 length of the through hole. 5. A rotor assembly having a rotating shaft, a cup-shaped bracket, a cover attached to an open end of the bracket so as to wrap the rotor assembly, and the rotation provided at the center of a closed end side of the bracket. A sleeve supporting the shaft, a thrust receiving plate provided at one end of the sleeve facing the end of the rotating shaft, and a spiral groove or at least one of the outer periphery of the rotating shaft or the inner periphery of the sleeve. Providing a herringbone groove to form a radial hydrodynamic bearing, and forming a thrust hydrodynamic bearing by providing a spiral groove or a herringbone groove on at least one of the end of the rotating shaft or the thrust receiving plate, At the center of the cover, a sleeve that supports the rotation shaft, and at least the outer circumference of the rotation shaft or the inner circumference A spiral groove or a herringbone groove is provided on one side to form a radial hydrodynamic bearing, and a lubricant is injected into the hydrodynamic bearing, and a sealing member is provided at an open end of the sleeve disposed on the cover. Wherein the gap between the end of the rotating shaft and the sealing member is filled with a lubricant. 6. The motor according to claim 5, wherein the sleeve is integrally formed of the same material as the bracket or the cover. 7. The motor according to claim 5, wherein the sealing member is fixed to the sleeve via a ring-shaped, column-shaped, or prism-shaped elastic sealing material. 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 a 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 into the through hole, and a second sealing member is fitted and fixed in the through hole. The motor according to claim 6, claim 7, claim 8, or claim 9. 11. The motor according to claim 10, wherein the through-hole and the second sealing member are fastened by providing a screw portion. 12. The motor according to claim 10, wherein a gap between the second sealing member inserted into the through hole and the through hole is filled with an adhesive.