JP2001178066A - Ball bearing without inner ring, and motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball bearing without an inner ring, which can enhance work efficiency by solving the difficulty in setting up, and where the user can arbitrarily select as to whether it is fixed position pre-load or fixed-pressure pre-load. SOLUTION: This is a ball bearing without an inner ring, which is provided relatively slidably with a first outer ring member 14, having a downward circular taper and a second outer ring member 15 having an upward circular taper provided opposite to this first outer ring member 14, so as to constitute an outer-rolling groove 16, and a ball 12 is retained at a prescribed interval between this outer-rolling groove 16 and the circular inner rolling groove 11a provided around a rotary shaft, by means of a retainer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner ring-less ball bearing and a motor using the same.

[0002]

2. Description of the Related Art In recent years, many spindle shafts of motors for driving media such as CDs use a ball bearing which holds a ball between an inner ring and an outer ring. However, since a ball bearing that holds a ball between an inner ring and an outer ring is expensive, a bearing without an inner ring has been proposed. Hereinafter, description will be made with reference to FIGS.
FIG. 5 is a cross-sectional view showing an example in which a bearing without an inner ring is attached to a rotating shaft of a motor or the like, and FIG. 6 is a schematic plan view for explaining the assembling process. In the figure, 1 is a rotating shaft, 1a
Are annular first inner rolling grooves 1b provided on the outer periphery of the rotating shaft 1 and 1b are spaced apart from the inner rolling grooves 1a by a predetermined distance.
An annular second inner rolling groove provided on the outer periphery of the rotating shaft 1. 2 is the inner rolling groove 1a and the outer rolling groove 1
It is a ball rolling in b. Reference numeral 3 denotes a first retainer which holds the balls 2 rolling in the first inner rolling grooves 1a at a predetermined interval from the adjacent balls, and 4 similarly designates the second inner rolling grooves 1b. This is a second retainer that holds the balls 2 rolling inside at predetermined intervals from the adjacent balls 2. Reference numeral 5 denotes a first outer ring which is provided so as to face the first inner rolling groove 1a, has an annular groove having a cross-sectional diameter larger than the diameter of the ball 2 on the inner wall, and holds the ball 2. Reference numeral 6 denotes a second outer ring which is provided so as to face the second inner rolling groove 1b and has an annular groove having a cross-sectional diameter larger than the diameter of the ball 2 on the inner wall and holds the ball 2. 7 is 2 above
An urging spring 8 for urging the two outer races 5 and 6 in the separating direction is fixed to the upper end of the first outer race 5, and has an inner diameter of the outer race 5 and a shaft 1.
A first shaft cover 9 that fills a gap between the first outer ring 6 and a second shaft cover 9 is fixed to the lower end of the second outer ring 6 and fills a gap between the inner diameter of the outer ring 6 and the shaft 1.

[0003]

In the conventional inner ring-less ball bearing thus formed, the ball 2 is attached to the shaft 1 also serving as the inner ring in the ball holding hole of the retainer 3 so that the ball 2 does not fall. Attach the outer ring while doing the assembly work. Specifically, in the step of inserting the balls 2, the shaft 1 is moved to one side of the outer rings 5 and 6 (FIG. 6), and a predetermined number of balls 2 are inserted. Then, after arranging the balls 2 at equal intervals with a jig,
After the two divided retainers 3 were inserted from above and below, the retainers were fixed together by caulking or welding. However, since the inner diameter of both ends of the outer ring is formed to be a proper inner diameter when the ball is accommodated in the ball holding groove provided on the inner circumference of the outer ring, the diameter is small, and the number of balls is large. Therefore, there is a disadvantage that it cannot be easily assembled.

It is an object of the present invention to provide an inner ring-less ball bearing which can arbitrarily select either fixed-position preload or constant-pressure preload, which solves difficulties during assembly and improves workability.

[0005]

In order to solve the above-mentioned problems, it is preferable that the inner peripheral surface of the outer ring is opposed to an annular inner rolling groove provided on the outer periphery of the rotating shaft. An inner ring-less ball bearing in which an annular outer rolling groove is provided and a ball is held at a predetermined interval by a retainer in the two rolling grooves, a first outer ring member having a downward annular tapered portion, A second outer ring member having an upwardly-facing annular tapered portion provided opposite to the first outer ring member, and the two outer ring members are relatively slidably provided, and the two annular taper members are provided. This can be achieved by forming an outer rolling groove in which the ball rolls by the portion. Further, as in the second aspect of the present invention, it can be attained by slidably fitting a second outer ring member into the first outer ring member. Further, as in the invention according to claim 3, the second
This can be achieved by slidably fitting the first outer ring member into the outer ring member. Further, the present invention can be achieved by a motor using an inner ring-less ball bearing configured as described above, as in the invention described in claim 4.

[0006]

Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of an inner ring-less ball bearing of the present invention. In FIG. 1, J1 is a first inner ring-less ball bearing. Reference numeral 11 denotes a separate rotating shaft that is supported by the inner ring-less ball bearing J1. Reference numeral 11a denotes an annular inner rolling groove provided on the outer periphery of the rotating shaft 11. The cross-sectional shape of the rolling groove 11a is a circular groove. In addition, the groove width is formed larger than the diameter of the ball 12 in order to correspond to the preload. 13 is a retainer for holding the ball 12 at a predetermined interval;
Reference numeral 14 denotes a first outer ring member having a downwardly directed annular tapered portion 14a on the inner periphery, followed by a large-diameter portion 14b, and reference numeral 15 denotes a second outer ring member having an upwardly directed annular tapered portion 15a on the inner periphery. is there. In the state of the bearing alone before being attached to the shaft, the second outer ring member 15 is slightly pressed into the large-diameter portion 14b, and is mounted on the shaft.
In this state, the upwardly-facing annular tapered portion 15a and the oppositely-facing annular tapered portion 14a form an annular outer rolling groove 16 in this state. The cross-sectional shape of the outer rolling groove 16 is a circular groove, and the groove width is formed larger than the diameter of the ball 12.

Next, the procedure for assembling the first embodiment thus constructed will be described. First, the upwardly-facing annular tapered portion 15a of the second outer ring member 15 (or the first outer ring member 14) is formed. The retainer 13 with the ball loosely fitted in the ball holding hole is placed on the top. At this time, since the inner peripheral side of the ball holding hole of the retainer 13 is formed smaller than the ball diameter, the ball 12 does not fall off. Next, the second outer race member 15 is slightly pressed into the large diameter portion 14b. Next, the shaft cover 17 is fixed to the first outer ring member 14, and the assembly of the inner ring-less ball bearing J1 alone in the first embodiment is completed.

[0008] The thus constructed inner ring-less ball bearing J
A description will be given of attaching 1 to the shaft 11. Inner ring-less ball bearing J
When the shaft 11 is inserted into the ball, the ball 12 is pushed away by the shaft 11 toward the outer race. Eventually, the ball 12 can fit into the inner rolling groove 11a at a position corresponding to the inner rolling groove 11a. Next, the second outer ring member 15 is connected to the large diameter portion 1.
Press completely into 4b. This is the inner ringless ball bearing J1
Is completed on the shaft 11.

As described above, in the first embodiment, the first outer ring member 14 having the downwardly tapered portion 14a on the inner periphery of the outer ring and the large outer diameter portion 14b, and Since it is configured separately from the second outer race member having the upwardly-facing annular tapered portion 15a, the ball 12 and the retainer 1 are assembled in the process of assembling the inner race-less ball bearing J1 to the shaft 11 also serving as the inner race.
It is easy to assemble without putting too much effort into incorporating 3.

Next, FIG. 2 is a sectional view showing a first embodiment in which the shaft is held by using two (J1, J2) inner ring-less ball bearings J described above. explain. Here, for convenience of explanation, the two inner ring-less ball bearings will be described as J1 and J2, but the two may be the same. In the drawing, reference numeral 18 denotes a bearing housing implanted on a stator base (not shown). Reference numeral 19 denotes a first stopper such as a C-type clamp fitted in a positioning groove 18a provided on the inner periphery of the bearing housing 18. The first inner ring-less ball bearing J1 is placed on the first stopper 19, and the second inner ring-less ball bearing J2 is placed with the spacer 20 interposed therebetween.
Put. Next, when the shaft 11 is inserted around the center, the balls 11 of the two inner ring-less ball bearings J1 and J2 are pushed away by the shaft 11 to the outer ring side.
The two inner rolling grooves 11a and 11b correspond to the two inner rolling grooves 11a and 11b, and are fitted into the two inner rolling grooves 11a and 11b. Here, the second outer ring member 1 of the two inner ring-less ball bearings J1 and J2
5 is completely pressed into the large diameter portion 14b. The press fitting may be performed for each bearing. Finally, if the second stopper 21 is fitted into the positioning groove 18b provided on the inner periphery of the bearing housing 18, the assembly of the bearing is completed. However, since the preload is fixed, the two stoppers 19 and 21 are fixed. The positioning grooves 18a and 18b to be
Positioning is performed such that the position 2 is slightly inside (position close to each other) from the center of the inner rolling grooves 11a and 11b, so that a fixed position preload is applied.

As described above, since the inner ring-less ball bearings J1 and J2 are used as fixed-position preloads, assembly is extremely simple. In addition, it is possible to easily obtain a fixed-position preload.

Next, FIG. 3 shows two inner ring-less ball bearings J.
It is sectional drawing explaining 2nd Example which used J1 and J2 for constant-pressure preload. In this embodiment, the inner ring-less ball bearings J1 and J2 may be the same. In FIG.
Is a bearing housing implanted in a stator base (not shown). On the inner periphery of the bearing housing 22, a shaft 11 is provided at the center.
Is provided with a projecting portion 23 having a through-hole into which the can be loosely fitted. One of the protruding portions 23 (upper in this example) has a first
Of the inner ring-less ball bearing J1 is formed to have a diameter substantially equal to the outer circumference of the inner ring-less ball bearing J1 so that the inner ring-less ball bearing J1 can be press-fitted, and a second inner circumference 22b is formed at the other end. Second inner circumference 22
“b” has a diameter slightly larger than the first inner circumference 22a and a thickness that allows the inner ring-less ball bearing J2 to be loosely fitted. This bearing housing 22
Of the inner ringless ball bearing J1 in the first inner circumference 22a of the first
Until the outer ring member 14 abuts on the protrusion 23. Next, the shaft 11 is adjusted to a position where the ball 12 fits into the inner rolling groove 11a.
The second outer race member 15 is completely press-fitted into the large diameter portion 14b of the first outer race member 14 when the second outer race member 15 has been fitted into 1a.

Next, a preload spring 24 is inserted into the second inner periphery 22b from the side opposite to the projection 23 of the bearing housing 22, and then the inner ring-less ball bearing J2 is inserted into the inner rolling groove 11b. Adjust so that it fits in. Ball 12
The second outer race member 15 is completely press-fitted into the large diameter portion 14b of the first outer race member 14 when is fitted into the inner rolling groove 11b. Thereby, the inner ring-less ball bearing J2
Is urged by the preload spring 24 in the direction of coming out of the second inner circumference 22b, but the ball 12 does not get caught by the lower side wall of the inner rolling groove 11b. Therefore, the shaft 11 is pulled downward, and the ball 12 is pushed down the annular tapered portion 14a of the first outer ring member 14 downward on the upper side of the inner rolling groove 11a.
Abuts on the protruding portion 23, so that it does not go down any further. Therefore, constant pressure preload is applied to the inner ring-less ball bearings J1 and J2.

As described above, since the inner ring-less ball bearings J1 and J2 are used as a constant pressure preload, assembly is extremely simple.
Also, a constant pressure preload can be easily obtained.

FIG. 4 is a sectional view showing an example in which the fixed position preload shown in FIG. 2 is used for a small motor. In FIG.
Reference numeral 1 denotes a stator base for supporting the bearing housing 18;
Reference numeral 2 denotes an inverted cup type rotor case fixed to the shaft 11 by a short cylindrical support portion 32a at the center thereof. 33 is a magnet fixed to the inner periphery of the rotor case 32, 34 is a stator core fixed to the outer periphery of the bearing housing 18, and 35 is a coil wound around the stator core 34. Also in this example, the bearing housing 18 is planted in the center of the stator base 31 and the bearing housing 18
The stator core 34 is fixed in advance (or in a later step), and the coil 35 is wound around the stator core 34.
A description will be given of a case in which the shaft 11 is supported by the inner ring-less ball bearing in the stator configured as described above.
First, the inner ring-less ball bearing J1 is placed in the bearing housing 18, while the shaft 11 to which the rotor case 32 is fixed in advance is inserted into the bearing housing 18 in this state. Then, the ball 12 is adjusted to a position where the ball 12 fits into the inner rolling groove 11a. When the ball 12 fits into the inner rolling groove 11a, the second outer ring member 15 is moved to the large diameter of the first outer ring member 14. Press completely into part 14b. Similarly, the spacer 20 is inserted into the bearing housing 18, and the inner ring-less ball bearing J2 is further inserted.
b, and the second outer race member 15 is completely pressed into the large diameter portion 14b of the first outer race member 14 when the ball 12 is fitted into the inner rolling groove 11b. . Finally, the first stopper 1 is inserted into the positioning groove 18a.
The assembly is completed by fitting 9.

As described above, since the inner ring-less ball bearings J1 and J2 are used for the motor as the fixed position preload, assembly is extremely simple. Also, a constant pressure preload can be easily obtained.

[0017]

According to the present invention, as described above, the first outer ring member having the downward (or upward) annular tapered portion,
A second outer ring member having an upwardly (or downwardly) annular tapered portion provided opposite to the first outer ring member, and the two outer ring members are relatively slidably provided; The outer rolling groove, in which the ball rolls, is formed by the two annular tapered parts to form an inner ring-less ball bearing. When assembling the bearing to the motor, the assembling of the bearing is simple, so the assembly time can be reduced and the fixed position Either preload or constant pressure iron can be used easily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of an inner ring-less ball bearing of the present invention.

FIG. 2 is a sectional view showing a first embodiment in which inner ring-less ball bearings J1 and J2 are used for fixed-position preload.

FIG. 3 is a cross-sectional view illustrating a second embodiment in which two inner ring-less ball bearings J1 and J2 are used for constant-pressure preload.

FIG. 4 is a sectional view showing an example in which the fixed position preload of FIG. 2 is used for a small motor.

FIG. 5 is a cross-sectional view showing a conventional example in which a bearing without an inner ring is attached to a rotating shaft of a motor or the like.

FIG. 6 is a schematic plan view for explaining an assembly process of a conventional bearing.

[Explanation of symbols]

 1,11 shaft 2,12 ball 3,13 retainer 14 first outer ring member 15 second outer ring member 16 outer rolling groove 17 shaft cover 18,22 bearing housing 19,21 stopper 20 spacer 24 preload spring

Claims (4)

[Claims] An annular outer rolling groove is provided on an inner periphery of an outer ring so as to face an annular inner rolling groove provided on an outer periphery of a rotating shaft, and a predetermined interval is provided between the two rolling grooves by a retainer. In the inner ring-less ball bearing having a ball held therein, a first outer ring member having a downward annular tapered portion and a second outer ring member having an upward annular tapered portion provided opposite to the first outer ring member. An inner ring-less ball bearing comprising an outer ring member, the two outer ring members being slidably provided relative to each other, and an outer rolling groove in which the ball is rolled by the two annular tapered portions. 2. The inner ring-less ball bearing according to claim 1, wherein a second outer ring member is loosely fitted into the first outer ring member so as to be slidable. 3. The inner ring-less ball bearing according to claim 1, wherein the first outer ring member is freely slidably fitted into the second outer ring member. 4. A motor using the inner ring-less ball bearing according to any one of claims 1 to 3.