JP2002339965A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durable bearing device capable of preventing the permanent deformation of a pre-load spring member for regulating the position of a rotary shaft in the axial direction by two ball bearings. SOLUTION: Stepped parts of first and second bearing holders 18 and 20 for supporting the rotary shaft 11 are omitted, an outer ring 12b of the first ball bearing is pressed against a bearing regulating plate 30 by the urging force of a wave washer 25 of the pre-load spring member to regulate the position of the rotary shaft 11 in the axial direction. The press-in displacement of the rotary shaft 11 is regulated by a small space δ between end faces 24a of projecting parts at three part of an inner surface of the second bearing holder 20 and an outer ring 15b of the second ball bearing, and thermal expansion is absorbed by the wave washer 25. A trough part 25b pressed against a bottom wall 23 of the annular wave washer 25 is notched avoiding any interference with the projecting part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor bearing, and more particularly, to a means for removing a play in a thrust direction of a ball bearing.

[0002]

2. Description of the Related Art Conventionally, motors used in industrial equipment are:
Generally, the rotating shaft is supported by two ball bearings, but in order to ensure smooth rotation of the ball bearing, the inner ring is attached to the shaft as hard as possible by press-fitting, for example, and the outer ring is moved to the extent that it can move inside the bearing holder. Must mate. Then, only the outer ring of one of the two ball bearings is allowed to be fixed in the axial direction, and the other ball bearing is arranged to be movable in the axial direction.

FIG. 5 shows the mounting of a conventional radial ball bearing as a floating and ball bearing. A ball bearing 103 provided on a front panel 102 located on the output shaft 108a side of a housing 101 of a motor 100 is fixed, and an outer ring is fixed. 103a is the inner surface 104b of the opening step 104a of the bearing holder 104
And the inner surface 105a of the bearing lid 105 to fix in the axial direction. The other ball bearing 106 is slidable on the rotating shaft 108, and the outer ring 106 a is
07a and slidably supported.

The motor 100 has an outer surface 109a of a motor rotor 109 fixed to a rotating shaft 108 and an inner surface 111a of a magnetic pole 111 mounted on an inner surface of the housing 101.
Must be kept precisely at all times during rotation. Thus, as shown in FIG. 6B, the housing 101 is fixed so that the center of the mounting surface S of the magnetic pole 111 of the housing 101, the fitting surface Ta with the front panel 102, and the fitting surface U of the ball bearing 106 are not deviated. When 101 is centered and chucked by a machine tool, it is processed in a common process without breaking the same chucking. Thereby, the alignment of the center between the magnetic pole 111 and the bearing 106 is ensured.

On the other hand, the ball bearing outer ring 1 of the bearing holder 104
03a, the center must also be aligned with the magnetic pole 111 mounting surface S of the housing 101.
The fitting surface Tb of the front panel 102 with the housing 101 and the fitting surface V of the ball bearing outer ring 103a must be processed in a common step without breaking the same chucking state. However, as shown in FIG. 6 (a), in order to machine the fitting surface Tb, the ball bearing outer ring fitting surface V is opened to the chuck 112 side, so that the cutting tool 113 is moved from the chuck 112 side to the opening step portion 1.
It must be sent to the direction of arrow 04a (arrow w), and the opening step 104a of the bearing holder 104 becomes an obstacle, so that groping processing is inevitable and precise processing becomes difficult.

In order to overcome this obstacle, the motor 200 shown in FIG. 7 has the stepped opening 104a shown in FIG.
The bearing holder 204 provided on the front panel 202 is formed as a through hole 104b having no step, and the ball bearing 103 is made slidable so that the center alignment with the housing 101 is secured first. Then, the position of the rotating shaft 108 in the axial direction is not determined, so that the preload spring member 213 is placed between the bottom surface 107b of the bearing holder 107 at the rear end of the housing 101 and the ball bearing 106 as shown in FIG. Intervention, a preload is applied to the outer ring 106a of the ball bearing 106 by the urging force due to the elastic deformation of the preload spring member 213 and pressed forward, and this urging force is supported by the bearing lid 105 that regulates the outer ring 103a of the ball bearing. Thus, the position of the rotating shaft 108 in the axial direction is determined. According to this method, the inner ring, the steel ball, and the outer ring are always in contact under the pressure of the preload spring member 213, and the expansion and contraction due to the temperature change are absorbed by the preload spring member 213, and the rotating shaft 108 It can rotate smoothly under almost constant conditions (in FIG. 7, the same reference numerals are used for members common to FIG. 6).

[0007]

However, in this configuration, there is a danger that the output shaft 108a receives an unexpected pressing force in the axial direction, and the preload spring member 213 is pressed down until it exceeds the elastic limit and becomes completely flat. There is. For this reason, when the preload spring member 213 is permanently deformed and the pressing force is weakened, the rigidity of the bearing is weakened, and play is likely to occur against external vibration and impact.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a durable bearing device in which a smooth rotation can be obtained regardless of a temperature difference without a permanent deformation of a preload spring member.

[0009]

In order to achieve the above object, a bearing device according to the present invention comprises a ball bearing for supporting a rotating shaft with an inner ring, and a bearing holder for fitting an outer ring of the ball bearing. A preload spring member that abuts on an outer ring of the ball bearing to apply a preload to the ball bearing, wherein the bearing holder has a plurality of protrusions protruding toward the outer ring of the ball bearing. In addition, a notch is formed in the preload spring member to avoid interference with the protrusion.

A motor rotor is fixed to a rotating shaft supported by an inner ring of the ball bearing, and the bearing holder is formed in a motor housing in which magnetic poles arranged opposite to the motor rotor are fixed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bearing device according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a cross section of a first embodiment of the bearing device according to the present invention. The rotary shaft 11 of the motor 10 is slightly enlarged in diameter from the output shaft 11a, and the press-fit portion 11b of the inner race 12a of the first ball bearing 12 is formed.
Is formed. Further, the press-fit portion 1 of the second ball bearing 15 disposed on the opposite side of the first ball bearing 12 to the inner ring 15 a of the rotating shaft 11 via the fixed portion 11 c of the motor rotor 13.
1d is formed by reducing its diameter.

A first bearing holder 18 penetrates an opening 19 at a front portion of the housing 16 where the output shaft 11a protrudes, and the outer diameter of an outer ring 12b of the first ball bearing 12 is slidably fitted therein. An opening 21 is formed on the side of the housing 16 opposite to the output shaft 11a side as a second bearing holder 20 into which the outer diameter of the outer ring 15b of the second ball bearing 15 is slidably fitted.

The opening 21 of the second bearing holder 20 is
2 extend in the axial direction and are closed by a bottom wall 23. Bottom wall 2
3 extends from the peripheral wall 22 toward the open end of the opening 21.
Extend at three locations at equal intervals along (see FIG. 2 (c)),
Outer ring 15 of second ball bearing 15 in second bearing holder 20
The sliding range of b is regulated. Further, the bottom wall 23 is provided in the space where the protrusion 24 extends in the second bearing holder 20.
Then, a wave washer 25 is inserted as a preload spring member elastically contacting the outer ring 15b of the second ball bearing 15.

The housing 16 is connected to the first shaft on the output shaft 11a side.
Front panel 26 forming opening 19 of bearing holder 18
And a casing 28 in which a magnetic pole 27 disposed opposite to the motor rotor 13 is fixed. Fitting surface 28 between fixed surface 28a of magnetic pole 27 of casing 28 and front panel 26
b) and the casing 28 of the front panel 26
And through the opening 19 of the first bearing holder 18 so as to pass through the fitting surface 26a and the concentric surface 26a, the center alignment relationship of the first ball bearing 12 with respect to the magnetic pole 27 is precisely secured,
The first ball bearing 12 is slidably fitted in the opening 19.

Further, the fixed surface 28a of the magnetic pole 27 of the casing 28 and the opening 21 of the second bearing holder 20 are machined concentrically, whereby the second ball bearing 15 with respect to the magnetic pole 27 is formed.
Since the center matching relationship of the first and second is precisely secured, the first and second
The motor rotor 13 supported by the ball bearings 12 and 15 has the magnetic pole 2
The precision of the alignment for 7 is improved.

In the rotating shaft 11, the first ball bearing inner ring 12
a From the press-fitting portion 11b to the motor rotor fixing portion 11c, the stepped portion a1 and the motor rotor fixing portion 11c, and from the space regulating shaft 11d of the first and second ball bearings 12, 15 to the second ball bearing inner ring 15a. When the distance A1 to the step portion a2 which shifts to the press-fitting portion 11e is defined, the distance A2 including the ball bearings 12, 15 after the ball bearings 12, 15 are press-fitted is automatically determined. Based on this distance, the housing front panel 26
Is set from the opening surface 26a to the front edge end surface 24a of the protrusion 24, and the range δ in which the second ball bearing 15 can slide on the peripheral wall 22 is defined.

The wave washer 25 shown in FIG. 2 (a) is a plan view of an annular thin metal plate curved continuously in a wave pattern on both sides along the circumference. As shown in FIG. Three peaks 25a and valleys 25b are alternately provided on the wave washer 25 alternately. Notches 25c are formed at three valleys 25a of the wave washer 25 so as not to interfere with the protrusions 24 provided on the peripheral wall 22 of the opening 21 of the second bearing holder 20, and the notches 25c are formed in the protrusions 24. When engaged, it also performs a locking function as a detent for the wave washer 25. The washer 25 is shown in FIG.
2B, the maximum undulation width d of both end faces of the valley and the hill in the free state is equal to the bottom wall 23 of the projection 24 as shown in a side view along the line BB in FIG. From the second ball bearing outer ring 15b
Is formed to be greater than the distance k to.

The rotating shaft 11 on which the first and second ball bearings 12 and 15 are mounted is inserted into the housing 16 so that the front panel 2
6 and the casing 28, and the first and second ball bearings 1
2 and 15 are the first bearing holder 18 and the second bearing holder 2
0. Further, the bearing control plate 30 is attached to the front panel 2.
6, when the outer surface of the first ball bearing 12 and the opening surface 26a of the front panel 26 are flush with each other, the maximum undulation width d of the wave washer 25 in the thickness direction is compressed and reduced in the thickness direction. The biasing force corresponding to the reduced displacement is applied to the outer ring 1 of the second ball bearing.
5b, and the urging force acts on the outer race 12 of the first ball bearing 12.
The position of the rotating shaft 11 in the axial direction is determined by being supported by the bearing regulating plate 30 regulating b.

Although the output shaft 11a is exaggerated in FIG. 1, even if the output shaft 11a can be displaced in response to the acting force in the pushing direction, the output shaft 11a comes into contact with the protruding portion front end face 24a with a slight displacement δ, and the wave washer 25 Is not forcibly deformed beyond the elastic limit, so that sufficient durability is maintained. The rotating shaft 11 cannot be displaced in the drawing direction.

FIG. 3 shows a motor 50 according to a second embodiment of the bearing device according to the present invention, and the same reference numerals are used for members equivalent to those of the first embodiment. In the motor 50, the wave washer 25-1 is interposed between the first ball bearing 12 and the bearing restricting plate 30-1 to press the first ball bearing outer ring 12b rearward by the urging force due to its elastic deformation. Opening 1 of first ball bearing 12 in bearing regulating plate 30-1
9 is provided so that the end surface 30-1b extends to a position where a slight gap δ1 is formed between the end surface 30-1b and the first ball bearing outer ring 12b.

Although not shown, the protrusion 30 is attached to the wave washer 25-1.
Drilling the notch 25-1c that does not interfere with -1a is similar to the wave washer 25 of the first embodiment. The distance between the inner surface 30-1c of the bearing regulating plate 30-1 supporting the wave washer 25-1 and the first ball bearing outer ring 12b is k1. The maximum undulation width d is formed large as in the first embodiment.

When the bearing restricting plate 30-1 is mounted on the opening surface 26a of the front panel 26, the maximum undulation width d in the thickness direction of the wave washer 25-1 is compressed and reduced in the thickness direction, and the wave corresponding to the reduced displacement is reduced. Acting on the outer ring 12b of the first ball bearing,
This biasing force is supported by a projection 24-1 provided on the second bearing holder 20 with which the outer ring 15b of the second ball bearing abuts, and the axial position of the rotating shaft 11 is determined.

In FIG. 3, the output shaft 11a is exaggerated and can be displaced in accordance with the acting force in the pulling-out direction. However, the output shaft 11a is brought into contact with the projecting end face 30-1b of the bearing control plate with a slight displacement δ1. Since the wave washer 25-1 is not forced to deform beyond the elastic limit, sufficient durability is maintained. Contrary to the first embodiment, the rotating shaft 11 cannot be displaced in the pushing direction.

FIG. 4 shows another embodiment of the wave washer 25.
5-2 is bent to form an annular shape, and the protrusions 24 are equally spaced around the circumference.
The semicircular annular portion 25-2b is formed by bending the position avoiding the interference with / 30-1a inward. And each semi-annular part 25-
A mountain-shaped curved portion 25-2a is provided in the middle of 2b, and the wire ring 25-2 is formed in a curved shape that alternately undulates with each semi-annular portion 25-2b as a valley. The maximum undulation width d2 in the natural state is the maximum undulation width d of the first embodiment or the second embodiment.
Corresponding to

The embodiment of the bearing device according to the present invention has been described above. However, the above-described embodiment does not limit the present invention. For example, the protrusions 24 and 30-1a may be provided at two places or four places. The cutout position and the number of the wave washer 25 correspond to this. In addition, the preload spring member can have a shape other than the wave washer as long as it biases the outer ring, and thus various modifications and reconfigurations are possible within the scope of the claims. This is of course expected.

[0026]

As is apparent from the above description, according to the bearing device according to the present invention, since the projections for restricting the movement of the ball bearing outer ring are provided on the bearing holder, the axial movement of the output shaft is restricted. Thus, the preload spring member is not deformed until it is crushed, and the durability of the preload spring member is improved. Further, since the ball bearing is used as the ball bearing and the stepped portion of the inner diameter of the bearing holder is removed by the preload spring member, the processing is facilitated, the processing time is shortened, and the assembling accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a cross section of a first embodiment of a bearing device according to the present invention.

FIG. 2 is a schematic explanatory view of a preload spring member in the first embodiment of the bearing device according to the present invention, (a) is a plan view of a wave washer, and (b) is a line BB of (a). Side view along,
(C) is a perspective view explaining the relationship between a wave washer and a second bearing holder.

FIG. 3 is a plan view of a second embodiment of the bearing device according to the present invention.

4 (a) is a plan view of another embodiment of the wave washer of the bearing device according to the present invention, and FIG. 4 (b) is a side view taken along the line BB of FIG. 4 (a).

FIG. 5 is a side view showing an embodiment of a conventional bearing device in cross section.

6A and 6B are explanatory views of processing of a conventional bearing device, in which FIG. 6A is an explanatory view of processing of a front panel and one bearing holder, and FIG. 6B is an explanatory view of processing of a housing and the other bearing holder.

FIG. 7 is a side view showing another embodiment of the conventional bearing device in cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Motor 11 Rotating shaft 12 1st ball bearing 13 Motor rotor 15 2nd ball bearing 16 Housing 18 1st bearing holder 20 2nd bearing holder 24 Projection 25 Wave washer 27 Magnetic pole 30 Bearing control plate

Claims (2)

[Claims] 1. A ball bearing for supporting a rotating shaft with an inner ring, a bearing holder for fitting an outer ring of the ball bearing, a preload spring member for abutting against the outer ring of the ball bearing to apply a preload to the ball bearing. A bearing device having a plurality of projections projecting toward the outer ring side of the ball bearing in the bearing holder, and a notch formed in the preload spring member to avoid interference with the projections. A bearing device characterized in that: 2. A motor rotor is fixed to a rotating shaft supported by an inner ring of the ball bearing, and the bearing holder is formed in a motor housing in which magnetic poles arranged opposite to the motor rotor are fixed. The bearing device according to claim 1, wherein: