JP2004019709A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit capable of easily managing a fastening margin, and obtaining sufficient fixing force. <P>SOLUTION: In this bearing unit wherein a plurality of ball bearings are connected by a sleeve, a bush mounting part is mounted on an outer peripheral face of the sleeve, a bush having a cut part over its axial overall length and made out of an elastic material, is mounted on the bush mounting part, and a diameter of the bush is determined to be remarkably larger than that of the sleeve. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bearing unit used for information equipment, audio equipment, video equipment, and the like, and particularly to a bearing unit used for a magnetic disk device and an optical disk device.
[0002]
[Prior art]
An example of a conventional bearing unit will be described with reference to the drawings.
FIG. 6 is a sectional view showing a conventional example, and FIG. 7 is a front view thereof.
6 and 7, reference numeral 1 denotes a rolling bearing device.
Reference numeral 2 denotes a bearing unit, which is fitted and fixed in an insertion hole 3a provided in a housing 3 of the rolling bearing device 1.
[0003]
Reference numeral 4 denotes a sleeve, which is manufactured by molding a metal such as a steel material into a substantially cylindrical shape. The outer ring 6 of the rolling bearing 5 is fitted to both ends of the inner peripheral surface of the sleeve, and the plurality of rolling bearings 5 are connected. The bearing unit 2 is configured.
Reference numeral 7 denotes a shaft, which is fitted to the inner ring 8 of the rolling bearing 5 and is rotatably supported by the bearing unit 2 fitted to the housing 3.
[0004]
The conventional bearing unit 2 having such a configuration is fixed to the housing 3 by bonding or press-fitting when the outer peripheral surface of the sleeve 4 is fitted into the insertion hole 3a of the housing 3.
[0005]
[Problems to be solved by the invention]
However, in the conventional technique described above, when the bearing unit is fixed to the housing by bonding, a gap is provided between the outer peripheral surface of the sleeve and the insertion hole of the housing, and the gap is filled with an adhesive and fixed. There is a problem that a sufficient fixing force may not be obtained due to insufficient filling of the agent or insufficient solidification.
[0006]
Also, when the bearing unit is fixed to the housing by press-fitting, a margin is provided between the outer peripheral surface of the sleeve and the insertion hole of the housing. In such a case, there is a problem that a large amount of labor is required for managing the interference because the fixing force due to the interference is insufficient.
The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a bearing unit that facilitates management of interference and that can obtain a sufficient fixing force.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a plurality of rolling bearings and a bearing unit in which the rolling bearings are connected by a sleeve, wherein a bush mounting portion is provided on an outer peripheral surface of the sleeve, and the bush mounting portion has an axial direction. A bush made of an elastic material having a cutout formed over the entire length is mounted, and an outer diameter of the bush is slightly larger than an outer diameter of the sleeve.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a bearing unit according to the present invention will be described below with reference to the drawings.
First Embodiment Example FIG. 1 is a half sectional view showing a first embodiment, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a side view showing a rolling bearing device of the first embodiment. .
[0009]
Here, the half sectional view refers to a side view in which the upper half is a sectional view.
The same parts as those in the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted. 1 and 2, reference numeral 11 denotes a sleeve, which is made of a metal such as a steel material. The outer ring 6 of the rolling bearing 5 is fitted to both ends of the inner peripheral surface of the sleeve, thereby positioning the rolling bearing 5 in the axial direction. A fitting portion 13 provided with an abutment surface 12 against which the outer ring 6 abuts is provided, and a bush mounting portion 14 formed in a wide groove for mounting a bush 21 described later is provided on the outer peripheral surface thereof. It is a cylindrical member provided.
[0010]
The bush 21 is a cylindrical member made of an elastic material such as resin or hard rubber, and has an axial length substantially equal to the axial length of the bush mounting portion 14.
The bush 21 has a plurality of outer circumferential grooves 22 formed in the circumferential direction of the outer circumferential surface thereof, and a notch 23 formed by cutting the side of the cylindrical portion over the entire length in the axial direction.
[0011]
The operation of the above configuration will be described.
The bearing unit 2 is configured such that the outer ring 6 of the rolling bearing 5 is fitted into the fitting portion 13 of the sleeve 11 by press-fitting or the like, and the side surface of the outer ring 6 is abutted against the abutting surface 12 to arrange the rolling bearing 5 on both sides with a predetermined shaft. The bush 21 is assembled by mounting the bush 21 on the bush mounting portion 14 of the sleeve 11 by expanding the notch 23 by utilizing its elasticity.
[0012]
The assembled bearing unit 2 is fixed to the housing 3 by pressing the outer peripheral surface of the bush 21 into the insertion hole 3a of the housing 3 as shown in FIG.
At this time, since the outer diameter of the outer peripheral surface of the bush 21 is provided to be slightly larger than the outer diameter of the sleeve 11, only the outer peripheral surface of the bush 21 is always press-fitted into the insertion hole 3a.
[0013]
FIG. 3 is a full sectional view of the housing 3 in order to facilitate understanding of a state in which the bearing unit 2 is fixed, and the bearing unit 2 is a half sectional view similar to FIG.
The fixing force between the bearing unit 2 and the housing 3 fixed in this manner, that is, the pull-out force, is the interference when the outer peripheral surface of the bush 21 is fitted into the insertion hole 3a, the thickness of the cylindrical portion of the bush 21, and the elastic coefficient. And the area of the outer peripheral surface of the bush 21.
[0014]
The press-fitting force when the bush 21 is inserted into the insertion hole 3a increases as the area of the outer peripheral surface of the bush 21 to be inserted increases, and reaches a maximum when all the outer peripheral surfaces are inserted into the insertion hole 3a. Become.
Therefore, by appropriately combining the thickness of the bush 21 and the ratio of the area of the outer peripheral surface to the outer peripheral groove 22, the number and arrangement of the outer peripheral grooves 22, and the elastic modulus of the material of the bush 21, the minimum removal force and the assembly It is possible to increase the allowable width of the interference while securing the press-fitting in consideration of the performance.
[0015]
As described above, in the present embodiment, by utilizing the elasticity of the bush, a cutout portion is provided over the entire length in the axial direction of the bush, so that the sleeve can be easily mounted on the bush mounting portion, and the thickness of the bush can be reduced. A bearing unit can be obtained in which the elasticity of the material is appropriately set and the fixing force of the bearing unit is secured, and the management width of the bushing allowance is expanded.
[0016]
Further, by providing a plurality of circumferential grooves in the circumferential direction of the bush, it is possible to mitigate an increase in press-in force when the bush is inserted into the insertion hole of the housing, and to provide a bearing unit with improved assemblability. Can be.
In addition, by making the bushing a material having elasticity, it is possible to prevent generation of dust such as shavings due to press-fitting even when the housing is made of a soft metal such as aluminum, an alloy thereof, or brass.
[0017]
Also, by using the elasticity of the bush, it is possible to attach and detach the bush many times.
Second Embodiment FIG. 4 is a half sectional view showing a second embodiment of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0018]
Reference numeral 41 denotes a bush, which is provided with an outer peripheral groove 22 and a notch 23 similar to the bush 21 of the first embodiment, but has a different outer peripheral surface 42.
That is, the bush 41 is formed into a slightly tapered shape such that the outer diameter of the end portion 43 in the axial direction is smaller than the outer diameter of the opposite end 44 in the insertion direction of the bush 41.
[0019]
The outer diameter of the end 43 is set to be larger than the outer diameter of the sleeve 11.
The operation of the above configuration will be described.
The bush 41 is mounted on the bush mounting portion 14 of the sleeve 11 by pushing and expanding the notch 23 as in the first embodiment, and inserting the end 43 of the bush 41 into the insertion hole 3 a of the housing 3. Press in by pushing in the axial direction.
[0020]
At this time, since the taper shape of the outer peripheral surface 42 of the bush 41 has a shape in which the interference increases gradually with the inserted length, the tightening force of the outer peripheral surface 42 rubs against the insertion hole 3a. The longer end 43 is weaker, and the opposite end 44, which is press-fitted into the insertion hole 3a at the end of press-fitting, is relatively stronger. Then, it is set so that an appropriate fixing force of the bearing unit 2 can be obtained at the end of the press-fitting.
[0021]
As a result, the press-fit at the initial stage of press-fit can be reduced, and the assemblability of the bearing unit to the housing can be improved.
When the material of the bush is resin, the outer peripheral surface of the insertion side, which has a long rubbing distance by the insertion hole, moves a long distance while maintaining a large tightening force, thereby causing plastic flow in the axial direction and causing the end of press-fitting. In this case, it is possible to prevent an extremely large press-in force from being generated, and to perform a smooth press-in operation.
[0022]
Although the above description has been made on the assumption that the outer peripheral surface of the bush is tapered, the change in diameter from the end to the opposite end is stepwise, for example, the outer peripheral surface between adjacent outer peripheral grooves is gradually little by little from the end side. The shape may be a step-like shape while increasing the diameter.
Thereby, the same effect as in the second embodiment can be obtained.
[0023]
Third Embodiment FIG. 5 is a half sectional view showing a third embodiment of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
Reference numeral 51 denotes a sleeve, which has the same abutment surface 12 and fitting portion 13 as the sleeve 11 of the first embodiment, but has a different shape in the vicinity of the abutment surface 12 of the fitting portion 13. .
[0024]
That is, a groove-shaped relief portion 52 is formed on the surface of the fitting portion 13 where the outer ring 6 on the abutting surface 12 side is fitted so as to have a diameter larger than the outer diameter of the outer ring 6. The axial width is set to approximately half the fitting length of the outer ring 6 in the axial direction.
Reference numeral 61 denotes a bush, which is provided with an outer peripheral groove 22 and a notch 23 similar to the bush 21 of the first embodiment, but the outer peripheral portion of the outer peripheral groove 22 at a position substantially opposed to the relief portion 52 of the sleeve 51. The groove width of the groove 62 is larger than the groove width of the other outer peripheral groove 22 and is formed into a shape that is substantially equal to the axial width of the throw portion 52.
[0025]
The operation of the above configuration will be described.
The operation of press-fitting the bearing unit 2 into the housing 3 is the same as that of the first embodiment, and the description is omitted.
When the press-fitting is completed, the fastening force applied to the outer ring 6 is transmitted to the sleeve 51 via the bush 61 by the fixing force applied to the bush 61, and this is a force for tightening the outer ring 6 toward the center.
[0026]
At this time, the fastening force applied to the outer race 6 is reduced by the relief portion 52 of the fitting portion 13 provided on the sleeve 51.
Further, the transmission of the fixing force at the center of the bush 61 to the fitting portion 13 side of the sleeve 51 is reduced by the outer circumferential groove 62 provided at the position substantially opposed to the escape portion 52 of the sleeve 51 provided on the bush 61.
[0027]
Thus, in addition to the same effects as in the first embodiment, the tightening force applied to the outer ring is reduced by the outer peripheral groove at a position substantially facing the relief portion provided on the sleeve and / or the relief portion provided on the bush. In addition, it is possible to prevent the outer ring of the rolling bearing from being reduced in diameter and the radial gap of the rolling bearing from being reduced.
Note that the same effects as described above can be obtained even if the bush of the third embodiment is a bush whose outer peripheral surface diameter changes similarly to the second embodiment.
[0028]
In each of the above-described embodiments and aspects, it is desirable that the corner formed by the circumferential groove and the outer peripheral surface of the bush be subjected to a corner R or chamfer so as to suppress an increase in press-in force. [0029]
【The invention's effect】
As described above, the present invention makes use of the elasticity of the bush to provide a cutout extending over the entire length of the bush in the axial direction to facilitate the mounting of the sleeve on the bush mounting portion. It is possible to obtain an effect that a bearing unit in which the management width of the bushing allowance is enlarged while securing the fixing force of the bearing unit by appropriately setting the elastic coefficient can be obtained.
[Brief description of the drawings]
1 is a half sectional view showing a first embodiment; FIG. 2 is a sectional view taken along line AA of FIG. 1; FIG. 3 is a side view showing a rolling bearing device according to a first embodiment; FIG. 5 is a half-sectional view showing a third embodiment. FIG. 6 is a cross-sectional view showing a conventional example. FIG. 7 is a front view showing a conventional example.
DESCRIPTION OF SYMBOLS 1 Rolling bearing device 2 Bearing unit 3 Housing 3a Insertion hole 4 Sleeve 5 Rolling bearing 6 Outer ring 7 Shaft 8 Inner ring 11, 51 Sleeve 12 Abutment surface 13 Fitting part 14 Bush mounting parts 21, 41, 61 Bush 22, 62 Outer peripheral groove 23 Notch 42 Outer peripheral surface 43 End 44 Opposite end 52 Escape

Claims (6)

In a bearing unit in which a plurality of rolling bearings and the rolling bearings are connected by a sleeve,
A bush mounting portion is provided on the outer peripheral surface of the sleeve, and a bush made of an elastic material having a cutout formed over the entire length in the axial direction is mounted on the bush mounting portion, and the outer diameter of the bush is equal to the outer diameter of the sleeve. A bearing unit characterized by being slightly larger. In claim 1,
A bearing unit, wherein a plurality of outer circumferential grooves are provided in a circumferential direction of an outer circumferential surface of the bush. In claim 1 or claim 2,
A bearing unit, wherein an outer diameter of an end in an axial direction of an outer peripheral surface of the bush is smaller than an outer diameter of an opposite end. In claims 1 to 3,
An inner peripheral surface of the sleeve was provided with a fitting portion having an abutting surface for abutting the outer rings of the plurality of rolling bearings in the axial direction, and a groove-shaped relief portion was formed near the abutting surface of the fitting portion. A bearing unit characterized in that: In claim 4,
A bearing unit, wherein an outer peripheral groove of an outer peripheral surface of the bush is arranged at a position substantially facing a relief portion of the sleeve. In claims 1 to 5,
The bearing unit is characterized in that the material of the bush is a resin material.

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