Rolling bearing unit

Abstract

To provide a rolling bearing unit for performing creep preventing measures without applying new machining to a rolling bearing or giving thermal load thereto.SOLUTION: A rolling bearing unit 1 includes a fixing member (a housing 10) as one of the housing 10 and a shaft 30, a rotary member (the shaft 30) as the other of the housing 10 and the shaft 30, a rolling bearing 20 arranged between the fixing member (the housing 10) and the rotary member (the shaft 30), and a shim plate 40 arranged between an axial end face 11a of the fixing member (the housing 10) and an axial end face 21a of a fixed ring (an outer ring 21) of the rolling bearing 20. At least to the side face on the side of abutting on the axial end face 21a of the fixed ring (the outer ring 21) out of both side faces of the shim plate 40, a friction material 50 is pasted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rolling bearing unit, and more particularly to a rolling bearing unit that takes measures against slippage (creep) occurring between a housing and a rolling bearing.

Background Art

[0002] Conventionally, in order to facilitate fitting when attaching a rolling bearing for supporting a motor shaft to a housing, a positive clearance is usually provided between the rolling bearing and the housing. However, when a rotational load due to unbalance of the rotating body acts on the outer ring with such a clearance present, it is known that slippage, so-called "creep", occurs in which the outer ring rotates relative to the housing. When such creep occurs, wear occurs on the fitting surface between the rolling bearing and the housing, the support of the rolling bearing in the housing becomes unstable, or the generated wear powder enters the inside of the rolling bearing, etc., which may cause problems such as inducing wear of other members.

[0003] Therefore, in order to prevent creep, for example, in Patent Document 1, it is proposed to form one or two concave grooves on the outer peripheral surface of the outer ring fixed to the housing and attach an O-ring in this concave groove. Further, in Patent Document 2, it is proposed to sandwich a paper-based friction material between the housing and the outer ring by attaching the paper-based friction material to the side surface of the outer ring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a configuration using an O-ring as in the technique described in Patent Document 1, there is a concern that the anti-creep effect may decrease over time due to deformation or deterioration of the O-ring. In addition, since the outer peripheral surface of the outer ring is grooved, there is also a risk of applying a load to the outer ring.

[0006] Further, in a configuration in which a paper-based friction material is attached to the outer ring as in the technique described in Patent Document 2, when attempting to increase the attachment strength of the paper-based friction material, it is conceivable to roughen the attachment surface (i.e., the end face of the outer ring). However, processing for roughening is required. In addition, it is also conceivable to clean the attachment surface by pickling or the like, or to perform thermal adhesion as an attachment method. However, it is necessary to mask portions other than the attachment surface of the rolling bearing during pickling, and when performing thermal adhesion, it is necessary to heat the entire outer ring, resulting in a large heating area. Furthermore, heating will apply a thermal load to the outer ring, and in extreme cases, there is also a risk of deformation of the outer ring.

[0007] Therefore, an object of the present invention is to avoid performing new processing on the rolling bearing or applying a thermal load when taking anti-creep measures.

Means for Solving the Problems

[0008] The above object of the present invention is achieved by the configuration of the following [1] related to a rolling bearing unit.

[0009] [1] One of the fixing members of the housing and the shaft, The other rotating member of the housing and the shaft, A rolling bearing disposed between the fixing member and the rotating member, A shim plate disposed between the axial end face of the fixing member and the axial end face of the fixed ring in the rolling bearing, A rolling bearing unit comprising: A rolling bearing unit, characterized in that a friction material is attached to at least one of the side surfaces of the shim plate that abuts against the axial end face of the fixed ring.

[0010] Further, preferred embodiments of the present invention relating to the rolling bearing unit relate to the following [2] to [6].

[0011] [2] The rolling bearing unit according to [1], wherein the friction material is a paper-based friction material having a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa. [3] The rolling bearing unit according to [1], wherein the friction material is a paper-based friction material having a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa in the atmosphere where the environmental temperature is -40°C to 160°C or in the lubricating oil where the environmental temperature is -40°C to 120°C. [4] The rolling bearing unit according to any one of [1] to [3], wherein the portion of the shim plate where the friction material is attached is roughened. [5] The rolling bearing unit according to any one of [1] to [3], wherein the shim plate and the friction material are thermally adhered. [6] The rolling bearing unit according to [4], wherein the shim plate and the friction material are thermally adhered. [Advantages of the Invention]

[0012] The rolling bearing unit of the present invention includes one fixed member of a housing and a shaft, the other rotating member of the housing and the shaft, and a rolling bearing disposed between the fixed member and the rotating member. A shim plate with a friction material is interposed between the axial end face of the fixed member and the axial end face of the fixed ring in the rolling bearing so that the friction material and the fixed ring are in contact with each other. Therefore, it is not necessary to form a groove for mounting an O-ring on the fixed ring of the rolling bearing, and an existing rolling bearing can be used as it is, which has high versatility.

[0013] Further, when the friction material is attached to the shim plate and roughening, pickling, or thermal adhesion is performed to increase the adhesion strength, no load is applied to the rolling bearing because these processes are performed on the shim plate. [Brief Description of the Drawings]

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the embodiments described below, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0016] [First Embodiment] FIG. 1 is a half-sectional view schematically showing only the upper half of a rolling bearing unit 1 according to a first embodiment of the present invention with respect to the central axis of the shaft. In the present embodiment, the rolling bearing unit 1 includes a housing 10 as a fixed member, a shaft 30 as a rotating member, and a rolling bearing 20 disposed between the housing 10 and the shaft 30. The rolling bearing 20 includes an outer ring 21 as a fixed ring fitted and fixed to the housing 10, an inner ring 22 as a rotating ring fitted and fixed to the shaft 30, and a plurality of rolling elements, balls 23, which are rotatably held by a cage 24 between the outer ring 21 and the inner ring 22.

[0017] The housing 10 has an inner peripheral surface into which the outer ring 21 is fitted, and an inward flange portion 11 that extends radially inward from the axial side of the outer ring 21 is formed. Further, the rolling bearing unit 1 further includes a shim plate 60 with a friction material, in which a friction material 50 is attached to one side surface of a shim plate 40 for gap adjustment in a gap between the axial end surface 11a of the inward flange portion 11 and the axial end surface 21a of the outer ring 21. In this case, the shim plate 60 with a friction material is interposed in the gap such that the other side surface of the shim plate 40 abuts against the axial end surface 11a of the inward flange portion 11, and the friction material 50 abuts against the axial end surface 21a of the outer ring 21.

[0018] And the shim plate 40 for gap adjustment is, for example, an annular thin plate made of metal as shown in FIG. 2, and stainless steel, iron, copper, brass, etc. can be used as the metal. And an annular friction material 50 is concentrically attached to one side surface of the shim plate 40.

[0019] The larger the adhesion area of the friction material 50 to the shim plate 40, the greater the creep prevention effect can be obtained. However, the ratio of the area of the friction material 50 to the area of the side surface of the shim plate 40 is preferably at least 10% or more, more preferably 30% or more, and even more preferably 50% or more.

[0020] Also, in order to increase the adhesion strength with the friction material 50, it is preferable that the attachment portion of the friction material 50 on the shim plate 40 is roughened.

[0021] As the friction material 50, it is preferably a wet paper-based friction material in which a paper-like sheet as a core material is impregnated with a synthetic resin. Here, the paper-like sheet contains fibers, a filler, and a friction modifier. Examples of the fibers include natural fibers such as cellulose, hemp, and wood pulp, organic synthetic fibers such as aromatic polyamide and polyphenol, and inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber. Examples of the filler include diatomaceous earth, clay, wollastonite, silica, and carbonate. Examples of the friction modifier include synthetic resin particles, rubber particles, graphite, and coke powder. On the other hand, examples of the synthetic resin include phenolic resin, imide-modified resin, melamine-modified resin, and oil-modified resin.

[0022] This paper-based friction material is obtained by forming a sheet from a kneaded mixture of the above-mentioned fibers, filler, and friction modifier, heating and curing it, and then cutting the resulting sheet-shaped material into an annular shape.

[0023] Also, the friction material is preferably a paper-based friction material having a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa. Since the gap between the axial end face 11a of the inward flange portion 11 and the axial end face 21a of the outer ring 21 can change over time, it is preferable that the compression deformation amount at a compression surface pressure of 0.2 MPa is 10 μm or more, more preferably 20 μm or more, and still more preferably 30 μm or more. Note that the upper limit of the compression deformation amount is suitably 150 μm or less.

[0024] Furthermore, since the gap between the axial end face 11a of the inward flange portion 11 and the axial end face 21a of the outer ring 21 can change due to temperature changes, the paper-based friction material preferably has a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa in the atmosphere where the environmental temperature is -40°C to 160°C, or in lubricating oil where the environmental temperature is -40°C to 120°C, more preferably 20 μm or more, and still more preferably 30 μm or more. Note that the upper limit of the compression deformation amount is suitably 150 μm or less.

[0025] The thickness of the paper-based friction material is preferably 100 μm or more, more preferably 200 μm or more, and still more preferably 300 μm or more. However, if the thickness of the paper-based friction material exceeds 1000 μm, delamination between layers is likely to occur due to the shearing force applied during creep. Therefore, the thickness of the paper-based friction material is preferably 1000 μm or less, more preferably 800 μm or less.

[0026] Incidentally, the thickness of the shim plate 40 may be adjusted according to the gap between the axial end face 21a of the outer ring 21 and the axial end face 11a of the inward flange portion 11 of the housing 10 so that the total thickness with the paper-based friction material is adjusted.

[0027] In the above, as a method of attaching the friction material 50, the attachment portion of the shim plate 40 is cleaned by pickling or the like, and an appropriate adhesive having oil resistance and heat resistance (specifically, phenolic resin, epoxy resin, other thermosetting resins, etc.) is applied thereto in consideration of the environment during use, and the friction material 50 is attached. For example, in this case, while the attachment surfaces are pressed against each other in a state of being heated to 170 to 350 °C, the temperature is maintained at this temperature for an appropriate time to cure the adhesive and perform thermal bonding.

[0028] In this way, pickling, thermal bonding, and roughening of the shim plate 40 for increasing the bonding strength when attaching the friction material 50 to the shim plate 40 can all obtain a good anti-creep effect without applying any load to the rolling bearing 20. Also, in this case, since the other side surface of the shim plate 40 is also roughened, the anti-creep effect can be further enhanced. Furthermore, since the shim plate 40 is thin, the amount of heat required for bonding can be significantly reduced as compared with the case of bonding the friction material 50 to the fixed ring of the rolling bearing 20.

[0029] In the above first embodiment, in the rolling bearing unit 1 of the inner ring rotation type in which the inner ring 22 rotates as the shaft 30, which is a rotating member, rotates, the case where the shim plate 60 with a friction material is used, in which the friction material 50 is attached to one side surface of the shim plate 40, has been described. However, as shown in FIGS. 3 (a modification of the first embodiment) and 4, the friction material 50 may be attached to both side surfaces of the shim plate 40. Even in this case, the same effects as those described in the above first embodiment can be obtained.

[0030] Also, even in the case of a modification of the first embodiment, as the shim plate 40, those described in the above first embodiment can be preferably used, and as the friction material 50, it is preferable to use the paper-based friction material described in the above first embodiment.

[0031] [Second Embodiment] FIG. 5 is a half-sectional view schematically showing only the upper half of the rolling bearing unit 1 according to the second embodiment of the present invention from the central axis of the shaft. In the rolling bearing unit 1 of the second embodiment, the housing 10 is a rotating member and the shaft 30 is a fixed member. Therefore, the outer ring 21 is a rotating ring and the inner ring 22 is a fixed ring.

[0032] Further, the shaft 30 has an outer peripheral surface on which the inner ring 22 is externally fitted, and has an outward flange portion 31 that extends radially outward from the axial side of the inner ring 22. And a shim plate 60 with a friction material, in which the friction material 50 is attached to one side surface of the shim plate 40, is disposed in a gap formed between the axial end surface 31a of the outward flange portion 31 and the axial end surface 22a of the inner ring 22. The shim plate 60 with a friction material is interposed in the gap so that the other side surface of the shim plate 40 abuts against the axial end surface 31a of the outward flange portion 31 and the friction material 50 abuts against the axial end surface 22a of the inner ring 22, thereby preventing the creep of the inner ring 22.

[0033] In the above second embodiment, in the rolling bearing unit 1 of the outer ring rotation type in which the outer ring 21 rotates as the housing 10, which is a rotating member, rotates, the case where the shim plate 60 with the friction material 50 attached to one side surface of the shim plate 40 is used has been described. However, as shown in FIG. 6 (a modification of the second embodiment) and FIG. 4, the friction material 50 may be attached to both side surfaces of the shim plate 40. Even in this case, the same effects as those described in the above second embodiment can be obtained.

[0034] Also, even in the case of the modification of the second embodiment, as the shim plate 40, those described in the above first embodiment can be preferably used, and as the friction material 50, it is preferable to use the paper-based friction material described in the above first embodiment.

Explanation of Reference Numerals

[0035] 1 Rolling bearing unit 10 Housing 11 Inner flange portion 11a Axial end face (of the inner flange portion) 20 Rolling bearing 21 Outer ring 21a Axial end face (of the outer ring) 22 Inner ring 22a Axial end face (of the inner ring) 23 Ball (rolling element) 24 Cage 30 Shaft 31 Outer flange portion 31a Axial end face (of the outer flange portion) 40 Shim plate 50 Friction material 60 Shim plate with friction material

Claims

1. One of the fixed members of the housing and the shaft, The other rotating member of the housing and the shaft, A rolling bearing disposed between the fixed member and the rotating member, A shim plate disposed between the axial end face of the fixed member and the axial end face of the fixed ring in the rolling bearing, A rolling bearing unit comprising: A rolling bearing unit, characterized in that a friction material is attached to at least the side surface of both side surfaces of the shim plate that abuts against the axial end face of the fixed ring.

2. The rolling bearing unit according to claim 1, wherein the friction material is a paper-based friction material having a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa.

3. The rolling bearing unit according to claim 1, wherein the friction material is a paper-based friction material having a compression deformation amount of 10 μm or more at a compression surface pressure of 0.2 MPa in the atmosphere where the environmental temperature is -40°C to 160°C or in the lubricating oil where the environmental temperature is -40°C to 120°C.

4. The rolling bearing unit according to any one of claims 1 to 3, wherein the portion of the shim plate to which the friction material is attached is roughened.

5. The rolling bearing unit according to any one of claims 1 to 3, wherein the shim plate and the friction material are thermally adhered.

6. The rolling bearing unit according to claim 4, wherein the shim plate and the friction material are thermally adhered.

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