JP3086397B2 - Motor thrust bearing structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust bearing structure for a motor, and is applicable to various motors such as various disk drive motors, audio motors, and streamer motors.

[0002]

2. Description of the Related Art An example of a conventional motor thrust bearing structure will be described with reference to FIG. 3 showing an example of a conventional streamer motor. However, FIG. 3 shows only the right half of the motor. The left half of the motor, not shown, is configured substantially symmetrically with the right half. In FIG. 3, a hole 1a is formed in the center of the motor substrate 1, and an upper portion of a cylindrical bearing holder 2 is inserted into the hole 1a. The bearing holder 2 has a flange 2 a on the outer periphery of the intermediate portion in the axial direction, and the flange 2 a is in contact with the lower surface of the substrate 1. The center hole of the stator core 3 is inserted into the outer periphery of the lower half of the bearing holder 2, and a bolt 5 that has penetrated the stator core 3 and the flange 2 a of the bearing holder 2 from below is screwed into the substrate 1. The stator core 3 and the bearing holder 2 are
It is fixed to. The stator core 3 is a laminated core in which a plurality of core elements are stacked, and has a plurality of salient poles radially,
A drive coil 4 is wound around each salient pole.

A pair of sliding bearings 6 and 7 made of a metal bearing are press-fitted and fixed to the upper and lower ends of the inner peripheral side of the bearing holder 2. Washers 11 and 12 made of metal are press-fitted into the upper and lower ends on the inner peripheral side of the bearing holder 2 from outside of the slide bearings 6 and 7 in the axial direction, and are fixed by press-fit surfaces 13 and 14. The rotating shaft 20 is inserted through the inner holes of the pair of slide bearings 6 and 7, and the rotating shaft 20 is rotatably supported. A gap is formed between the inner peripheral surfaces of the washers 11 and 12 and the outer peripheral surface of the rotating shaft 20. A pair of thrust members 15 and 27 are inserted into the outer peripheral surface of the rotating shaft 20. The thrust members 15 and 27 are disposed further axially outside of the washers 11 and 12 and face the washers 11 and 12, respectively. The thrust member 15 slides on the washer 11 on a surface 17 facing the washer 11, The member 27 is in sliding contact with the washer 12 on a surface 28 facing the washer 12.

A tape driving roller 24 is fixed to the outer peripheral surface of the upper end of the rotating shaft 20 by press fitting or the like. A part of the roller 24 and a part of the upper thrust member 15 are engaged, and the rotating shaft 20, the roller 24, and the thrust member 15 rotate integrally. A boss 16 is fixed to the outer peripheral surface of the lower end portion of the rotating shaft 20 by press fitting or the like.
A part of the boss 16 and a part of the lower thrust member 27 are engaged, so that the rotating shaft 20, the thrust member 27, and the boss 16 rotate integrally. The boss 16 is made of a metal, a resin, or the like, and the rotor case 21 is integrally fixed to the boss 16 by press-fitting, snap fit, or the like. The rotor case 21 is arranged so as to surround the stator core 3, and a cylindrical drive magnet 22 is fixed to the inner peripheral surface of the peripheral wall. The drive magnet 22 has N and S poles alternately magnetized in the circumferential direction. The inner peripheral surface of the drive magnet 22 faces the outer peripheral surface of the stator core 3 with an appropriate gap.

By controlling the energization of the drive coil 4 of each phase in accordance with the rotational position of the drive magnet 22 with respect to each salient pole of the stator core 3, the drive magnet 22 is urged in the circumferential direction by electromagnetic force, and 22, a rotor case 21, a boss 16, a rotating shaft 20, a roller 24
Is driven to rotate. As the rollers 24 and the boss 16 rotate, the thrust members 15 and 27 also rotate. The thrust members 15, 27 are in sliding contact with the washers 11, 12, respectively. The thrust members 15, 27 and the washers 11, 12 constitute a thrust bearing structure.

[0006]

In the prior art described above, the thrust members 15, 27 are made of a resin, for example, a polyacetal resin or the like with respect to the washers 11, 12 made of metal, so that the thrust members 11, 12 are made thrust. Member 1
5 and 27 are slid smoothly, and the difference in hardness between the two sliding members is increased to reduce wear. However, according to the conventional thrust bearing structure, the boss 16 for integrally connecting the pair of washers 11 and 12, the pair of thrust members 15 and 27, and the rotor case 21 to the rotating shaft 20.
For example, it requires many parts and has a disadvantage of low productivity. In addition, since many components are interposed between the fixed portion and the rotating body as described above, the press-fit allowance of the boss 16 to the rotary shaft 20 or the press-fit allowance of the roller 24 to the rotary shaft 20 is limited. There is also a disadvantage that the fixing strength of the roller 24 is weak.

The present invention has been made to solve such problems of the prior art. By devising a thrust bearing structure, the number of required parts can be reduced to improve productivity. An object of the present invention is to provide a motor thrust bearing structure capable of increasing a fixing margin of a member fixed to a rotating shaft and increasing the fixing strength.

[0008]

A thrust bearing structure for a motor according to the present invention comprises a rotating shaft, a pair of sliding bearings, a washer,
Thrust member, a rotor casing which drive magnet is mounted, sliding bearings, inserted through the rotary shaft to each of the inner bore and supported rotatably, the washer, the sliding shaft <br/> receiving a metal disposed axially outside of one by one, respectively, the thrust member is integrally rotatably arranged a rotating body and further face the washer axially outside of each washer, one thrust member
Is made of resin and connects the rotor case to the rotating shaft.
As described above, the rotor case is integrally formed by insert molding or welding and the thrust member slides on the washer . The other thrust member is also made of resin,
Formed integrally with the cylindrical roller and fixed to the rotating shaft
Tei may be. The thrust member is made of conductive powder.
It may have conductivity by being mixed.

[0009]

At least one of the thrust members is insert-molded or welded and fixed integrally with the rotor case, and is provided integrally with the rotating shaft. Further, since this thrust member is in sliding contact with the washer, the thrust member is
It has both the function of connecting the rotor case and the rotating shaft and the function as a part of the thrust bearing mechanism, contributing to a reduction in the number of parts. The at least one thrust member is made of a resin, and the washer slidingly contacting the thrust member is made of a metal.
Low wear.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thrust bearing structure for a motor according to the present invention will be described below with reference to FIGS. The same components as those of the conventional example shown in FIG. 1 and 2 also show only the right half of the motor as in FIG. 3, and the left half of the motor, not shown, is configured substantially symmetrically with the right half.

In FIG. 1, a hole 1a is formed in the center of a substrate 1 of a motor, and the upper portion of a cylindrical bearing holder 2 is inserted into the hole 1a. The bearing holder 2 has a flange 2a on the outer periphery of the intermediate portion in the axial direction, and the flange 2a
In contact with the lower surface of the. The center hole of the stator core 3 is inserted into the outer periphery of the lower half of the bearing holder 2.
And a bolt 5 that penetrates the flange 2a of the bearing holder 2 from below is screwed into the substrate 1 so that the stator core 3
And the bearing holder 2 are fixed to the substrate 1. The stator core 3 is a laminated core in which a plurality of core elements are stacked, has a plurality of salient poles radially, and a driving coil 4 is wound around each salient pole.

A pair of sliding bearings 6 and 7 made of a metal bearing are press-fitted and fixed to the upper and lower ends of the inner peripheral side of the bearing holder 2. Washers 11 and 12 made of metal are press-fitted into the upper and lower ends on the inner peripheral side of the bearing holder 2 from outside of the slide bearings 6 and 7 in the axial direction, and are fixed by press-fit surfaces 13 and 14. The rotating shaft 20 is inserted through the inner holes of the pair of slide bearings 6 and 7, and the rotating shaft 20 is rotatably supported. A gap is formed between the inner peripheral surfaces of the washers 11 and 12 and the outer peripheral surface of the rotating shaft 20. A pair of thrust members 15 and 26 are inserted into the outer peripheral surface of the rotating shaft 20. Each of the thrust members 15 and 26 is made of resin, and is further disposed outside the washer 11 and 12 in the axial direction. The upper thrust member 15 is opposed to the washer 11, and the lower thrust member 26 is a jetty 26 formed on the upper end surface.
a faces the washer 12. The thrust member 15 is in sliding contact with the washer 11 on a surface 17 facing the washer 11, and the thrust member 26 has a ridge 26 a that is in sliding contact with the washer 12 on a surface 18 facing the washer 12.

The lower thrust member 26 is integrally fixed to the outer peripheral surface of the lower end portion of the rotary shaft 20 and is rotatable integrally with the rotary shaft 20. The thrust member 26 and the rotating shaft 20 may be fixed to each other by any appropriate means. For example, press-fitting, welding, or insert molding may be used. Further, in order to increase the fixing strength or detachment strength between the thrust member 26 and the rotating shaft 20, the rotating shaft 2
Unevenness 20a, such as knurls, may be formed on the portion of the outer peripheral surface where the thrust member 26 is fixed. The thrust member 26 also functions as a boss that integrally connects the rotor case 21 and the rotating shaft 20.
, A rotor case 21 is integrally fixed by insert molding. The rotor case 21 is arranged so as to surround the stator core 3, and a cylindrical drive magnet 22 is fixed to the inner peripheral surface of the peripheral wall. Drive magnet 2
Reference numeral 2 denotes an N-pole and an S-pole alternately magnetized in the circumferential direction, and the inner peripheral surface of the drive magnet 22 faces the outer peripheral surface of the stator core 3 with an appropriate gap.

A tape drive roller 24 is fixed to the outer peripheral surface of the upper end portion of the rotary shaft 20 by press fitting or the like.
A part of the roller 24 and a part of the upper thrust member 15 are engaged, and the rotating shaft 20, the roller 24, and the thrust member 15 are engaged.
Are designed to rotate integrally. The roller 24 is made of a metal such as aluminum.

By controlling the energization of the driving coil 4 of each phase in accordance with the rotational position of the driving magnet 22 with respect to each salient pole of the stator core 3, the driving magnet 22 is urged in the circumferential direction by electromagnetic force, and The rotor case 21, the thrust member 26, the rotating shaft 20, and the roller 24 integrated with the rotation 22 are driven to rotate. As the roller 24 rotates, the thrust member 15 also rotates. Thrust member 15, 2
Numeral 6 is in sliding contact with the washers 11 and 12, respectively, and the thrust members 15, 27 and the washers 11, 12 constitute a thrust bearing structure.

The thrust member 26 and the rotor case 21 are
Although it is integrally formed by insert molding as described above, it may be integrally formed by welding and fixing instead. Here, insert molding refers to thrust member 26.
Is a method in which the metal rotor case 21 is inserted into a mold for molding the thrust member 26 and the rotor case 21 at the same time as the thrust member 26 is molded.
Further, welding and fixing means that after forming the resin thrust member 26 and the metal rotor case separately, the two are fitted together, and then a part of the thrust member 26 is melted by heat or the like and deformed. This is a method of fixing the thrust member 26 to the rotor case 21.

According to the embodiment described above, the one thrust member 26 is insert-molded or weld-fixed integrally with the rotor case 21 and is provided integrally with the rotary shaft 20. Is in sliding contact with the washer 12, so that the thrust member 26 has both a function of connecting the rotor case 21 and the rotating shaft 20 and a function as a part of the thrust bearing mechanism, thereby reducing the number of parts. This contributes to an improvement in productivity. Further, since the one thrust member 26 is made of resin, and the washer 12 slidingly contacting this thrust member 26 is made of metal, there is also an effect that a difference in hardness between the two is large and wear is small. Furthermore, since the number of components interposed between the thrust member 26 and the rotating shaft 20 is reduced, the press-fitting allowance of the thrust member 26 to the rotating shaft 20 increases, and the fixing strength between the thrust member 26 and the rotating shaft 20 can be increased. There are also effects that can be done.

In the case of a disk drive motor, since the rotor rotates at a relatively high speed, static electricity is likely to be generated due to friction with air in the rotor case, and when an information signal is recorded on a disk and read out therefrom. May be affected by static electricity. Therefore, when the thrust member 26 is formed, the thrust member 26 is given conductivity by mixing a conductive powder into the molding resin.
Therefore, the rotor case 21 may be grounded through the washer 12, the bearing holder 2, the substrate 1, and the like to release the static electricity generated in the rotor case 21.

As means for integrating the rotor case 21 and the thrust member 26, caulking or the like can be considered.
According to the caulking, the rotor case 21 or the thrust member 26 is
Is applied to the rotor case 21 and the rotor case 21 is likely to oscillate when rotating. In this regard, according to the above embodiment, since the rotor case 21 and the thrust member 26 are integrated by insert molding or welding and fixing, no stress is applied to the rotor case 21 or the thrust member 26, and the runout accuracy of the rotor case 21 is reduced. There is also an advantage that can be increased.

In the embodiment shown in FIG. 1, one of the pair of thrust members 15, 26 is made of resin and is insert-molded or welded and fixed integrally with the rotor case 21. The thrust member may also be formed of resin to serve as a part having another function.
FIG. 2 shows such an embodiment. In FIG. 2, a jetty 28 a formed on the lower surface of the thrust member 28 faces the washer 11 on the upper surface of the upper washer 11. The thrust member 28 is in sliding contact with the washer 12 on the surface 25 facing the washer 12 to form a thrust bearing. Thrust member 28
Is a cylindrical roller, and also serves as a streamer drive roller. Other configurations, especially the thrust bearing structure including the thrust member 26 and the washer 12 and the configuration around it are the same as those of the embodiment shown in FIG. 1. Description is omitted.

According to the embodiment shown in FIG. 2 , one thrust member 26 made of resin is insert-molded or welded and fixed integrally with the rotor case 21, and the other thrust member 28 is also made of resin as a cylindrical roller. Since the thrust members 26 and 28 are formed and slidably contact the washers 12 and 11 made of metal, the number of parts can be further reduced and productivity can be improved. , 28 and the washers 12, 11 have a large difference in hardness, so that wear is further reduced.
In addition, the same effects as the effects already described can be obtained by making the changes described for the embodiment shown in FIG.

[0022]

According to the first aspect of the present invention, the rotating shaft,
In a thrust bearing structure of a motor including a pair of slide bearings, a washer, a thrust member, and a rotor case on which a drive magnet is mounted, one of the thrust members is a rotor case.
And a rotary shaft is insert-molded or welded integrally fixed to the rotor case so as to connect, further, since this was the thrust member is a washer and sliding contact, the thrust member has a function of connecting the rotor casing and the rotary shaft, Since it also has a function as a part of the thrust bearing mechanism, it contributes to the reduction of the number of parts, and therefore, it is possible to improve the productivity. In addition, the one thrust member is made of resin, and the washer slidingly contacting this thrust member is made of metal. Therefore, there is an effect that a difference in hardness between the two is large and wear is small.

According to the second aspect of the present invention, the other thrust member is also formed of resin and has a cylindrical roller.
Since it is integrally formed and fixed to the rotating shaft, the other thrust member also has a function as a part of the thrust bearing mechanism and a function as a roller, further reducing the number of parts. There is a productivity improvement effect. Ma
According to the third aspect of the present invention, the thrust member is a conductive member.
By being mixed with conductive powder, it has conductivity,
Pass thrust members through washers, bearing holders, substrates, etc.
The rotor case to ground,
Static electricity can be released.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a thrust bearing structure for a motor according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the thrust bearing structure of the motor according to the present invention.

FIG. 3 is a sectional view showing an example of a conventional thrust bearing structure of a motor.

[Explanation of symbols]

 Reference Signs List 6 slide bearing 7 slide bearing 11 washer 12 washer 15 thrust member 16 thrust member 21 rotor case 22 drive magnet 28 thrust member

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 5/167 H02K 5/16 H02K 21/22

Claims (3)

(57) [Claims] 1. A rotary shaft, a pair of sliding bearings, washers, a thrust member, the thrust bearing structure of the motor drive magnet is a rotor casing mounted, the slide bearing, the rotary shaft to each of the inner bore inserted rotatably and supported by, said washer is made of a metal, disposed one by one respectively axially outwardly of the respective sliding bearings, the thrust member is further axially outward of each washer
Integrally rotatably disposed between the rotary member and opposed to the respective washer
The one thrust member is made of resin, and the rotor case
And have been insert-molded or welded fixed integrally with the rotor case so as to connect the said rotary shaft, this
A thrust bearing structure for a motor, wherein a thrust member slides on the washer . 2. The other thrust member is also made of resin, is formed integrally with a cylindrical roller, and is fixed to the rotating shaft.
Thrust bearing structure of the motor, characterized by being. 3. The thrust member according to claim 1, wherein a conductive powder is mixed.
It is characterized by having conductivity by being inserted
The thrust bearing structure for a motor according to claim 1 or 2, wherein: