JP7245711B2 - bearing device - Google Patents

Description

The present invention relates to a bearing device in which a rolling bearing is interposed between a shaft and a housing.

A bearing ring of a rolling bearing that receives a radial load acting between a shaft and a housing is fitted on the outer circumference of the shaft or the inner circumference of the housing. Fitting surfaces formed on the bearing ring, shaft, and housing are generally cylindrical surfaces. The fitting between the fitting surface formed on the inner circumference or outer circumference of the bearing ring and the fitting surface formed on the shaft or housing may be an interference fit, Select from normal fit and clearance fit. A bearing ring with a clearance fit can creep, or become displaced circumferentially with respect to its mating member, the shaft or housing.

For example, in a bearing device that supports the shaft of an automobile transmission in a housing via a rolling bearing, the bearing ring on the outer side of the rolling bearing is loosely fitted in the housing in order to facilitate assembly to the housing. Therefore, the outer bearing ring may creep due to an unbalanced load on the shaft when a load is applied or when rotating at high speed.

As the creep mechanism, it is known that a traveling wave is generated on the surface of the bearing ring, and the traveling wave moves the bearing ring itself. That is, when the rolling element load acts on the raceway surface of the bearing ring, the surface of the bearing ring protrudes directly under the bearing ring and undulates. When the bearing rotates, the rolling elements also revolve, so the waviness on the surface becomes a traveling wave. Traveling waves generated on the surface of the bearing ring behave in a peristaltic manner in the circumferential and radial directions over the load zone of the rolling bearing. The traveling wave tries to move the mating member in the direction opposite to the revolving direction of the rolling element, but it is pushed back by the resistance of the mating member (shaft or housing). That is, a creep that rotates in the same direction as the bearing rotation will occur.

Conventionally, it has been proposed to form a circumferential groove in the bearing ring or the mating member in order to suppress the creep of the bearing ring loosely fitted to the mating member, out of the inner and outer races provided in the rolling bearing. there is The circumferential groove is located directly below the raceway surface of the bearing ring in the radial direction, and extends radially from the fitting surface of the bearing ring or the mating member to the entire circumference in the circumferential direction. Such a circumferential groove acts as a relief groove in the load zone of the bearing ring that receives a radial load, and suppresses the occurrence of creep.

Japanese Patent No. 4466473

However, in Patent Document 1, the depth of the circumferential groove formed in the bearing ring or the mating member is set to be equal to or less than the maximum amount of elastic deformation that occurs in the bearing ring due to the radial load applied to the rolling bearing. With such a circumferential groove, the maximum radial load is applied to the rolling bearing between the shaft and the housing, and the maximum amount of elastic deformation is exerted on the fitting surface of the bearing ring that undulates directly below the raceway surface in the center of the load bearing area in the circumferential direction. When this occurs, the groove bottom surface of the groove portion of the bearing ring or mating member and the mating surface facing it come into contact at the maximum elastic deformation portion (wavy peak), and the groove edges on both sides of the circumferential groove will come into relatively strong contact with Since the mating member receives the above-described traveling wave to some extent at these contact portions, there is a concern that creep of the bearing ring may occur.

In addition, when a circumferential groove is formed in a bearing component having a raceway surface, if the circumferential groove is formed with a sufficient radial depth to suppress creep, the raceway of the bearing component, which is important for suppressing deformation of the raceway surface due to radial load, will be reduced. Since the minimum wall thickness from the surface is thin all around, there is concern that the roundness, strength, and rolling contact fatigue life of the rolling bearing may be reduced.

In view of the background described above, the problem to be solved by the present invention is to provide a bearing device in which the bearing ring of a rolling bearing is loosely fitted to a mating member, which is a shaft or a housing, while avoiding thinning of the bearing component having the raceway surface. , to further suppress the creep of the bearing ring.

In order to achieve the above object, the present invention comprises a shaft, a housing surrounding the shaft, and a rolling bearing interposed between the shaft and the housing, wherein the rolling bearing is positioned between the shaft and the housing. A bearing device having a bearing ring loosely fitted with a mating member, wherein the bearing ring and the mating member have fitting surfaces extending in a circumferential direction, wherein the bearing ring and the mating member at least one of which has a build-up member having a fitting surface for the bearing ring or the mating member, and a main body that supports the build-up member in the radial direction; A flank is formed so as to divide the fitting surface of the bearing ring or the mating member over the entire width by fixing, and the at least one flank is within the range of the radial load applied to the rolling bearing. A configuration is adopted in which a radial gap can be left between the bearing ring and the mating member in the load bearing zone when the maximum radial load is applied at .

According to the above configuration, at least one of the bearing ring and the mating member, which is the shaft or housing loosely fitted therewith, has a flank that divides the entire width of the fitting surface of the bearing ring or the mating member. , it is possible to create a radial gap extending over the full width of the mutual fit between the bearing ring and the mating member. The radial clearance remains even in the load bearing range when the maximum radial load within the range of radial loads applied to the rolling bearing between the shaft and the housing is applied. Therefore, in the region where the radial gap remains, even if the fitting surface of the bearing ring is deformed into a wavy shape, it does not come into contact with the mating member, and the wavy deformation acts as a traveling wave that creeps the bearing ring. do not have. As a result, creep of the bearing ring can be further suppressed as compared with the case of suppressing creep by means of a circumferential groove extending in the circumferential direction as in Patent Document 1. In addition, since the flank is formed by fixing the build-up member having the fitting surface of the bearing ring or the mating member to the main body that can be supported in the radial direction, the flank is formed in the bearing component having the raceway surface. There is no processing, and thinning of the bearing parts can be avoided.

Specifically, the main body has a cylindrical surface that supports the build-up member, and the build-up member radially overlaps the cylindrical surface of the main body with a finite length in the circumferential direction. It is preferable that it is formed in a ring shape. By doing so, the flank can be formed with a simple structure in which the ring-shaped padding member with ends is fixed to the cylindrical surface of the main body.

For example, the padding member may be press-fitted or injection-molded onto the cylindrical surface of the main body. By doing so, the padding member can be fixed to the main body by a simple means such as press-fitting or injection/hardening.

Preferably, only the bearing ring has the flank and the body of the bearing ring consists of a bearing part with a raceway surface. When a flank is formed on the mating member, the creep suppressing effect cannot be exhibited unless the flank is located in the load bearing region. On the other hand, if a flank is formed only on the bearing ring to secure the aforementioned radial clearance, even if the flank is located in a region different from the load direction, the bearing ring will remain constant. If creep occurs, the flank enters the load bearing region and the above-described radial clearance is formed, so that creep of the bearing ring can be suppressed thereafter.

As described above, the present invention provides a bearing device in which the bearing ring of a rolling bearing is loosely fitted to a mating member, which is a shaft or a housing, by adopting the above configuration, while avoiding thinning of the bearing component having the raceway surface. Creep of the bearing ring can be further suppressed.

1 is a front view showing a bearing device according to an embodiment of this invention; Sectional view of II-II line in FIG. Front view showing an outer bearing ring according to the embodiment FIG. 4 is an exploded sectional view of the outer race shown in FIG.

A bearing device according to an embodiment as an example of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 1 and 2 , the bearing device according to the embodiment includes a shaft 1 , a housing 2 surrounding the shaft 1 , and rolling bearings 3 interposed between the shaft 1 and the housing 2 .

Hereinafter, in an ideal state in which the designed rotation center line of the rolling bearing 3 and the rotation center line of the shaft 1 coincide, the direction along the rotation center is referred to as the "axial direction." In addition, the direction along the circumference of the circle around the rotation center line is referred to as the "circumferential direction". A direction perpendicular to the rotation center line is called a "radial direction".

Shaft 1 rotates relative to housing 2 . Shaft 1 is, for example, a transmission shaft provided in a motor vehicle transmission.

The shaft 1 has a fitting surface 1a extending in the circumferential direction. The fitting surface 1a is formed in the shape of a cylindrical surface concentric with the rotation center line of the shaft 1. As shown in FIG.

The housing 2 is stationary with respect to the shaft 1 and radially supports the rolling bearing 3 . The housing 2 is, for example, a bulkhead formed as part of the transmission case of a motor vehicle.

The housing 2 has a circumferentially extending mating surface 2a. The fitting surface 2a is formed in the shape of a cylindrical surface surrounding the fitting surface 1a of the shaft 1 from the outside. The center line of the fitting surface 2 a is set concentrically with the rotation center line of the shaft 1 .

The rolling bearing 3 rotatably supports the shaft 1 with respect to the housing 2 and receives a radial load F acting between the shaft 1 and the housing 2 . In this bearing device, it is assumed that the radial load is applied in one direction. A radial load F is applied to the rolling bearing 3 between the fitting surface 1a of the shaft 1 and the fitting surface 2a of the housing 2 during operation of the bearing device.

The rolling bearing 3 comprises an inner bearing ring 4 attached to the shaft 1, an outer bearing ring 5 attached to the housing 2, and a plurality of rolling elements 6 interposed between the bearing rings 4, 5. , and a retainer 7 that maintains the circumferential spacing between these rolling elements 6 . A deep groove ball bearing is illustrated as the rolling bearing 3 .

The inner bearing ring 4 is an annular bearing component having a raceway surface 4a extending in the circumferential direction on the outer peripheral side and a fitting surface 4b extending in the circumferential direction on the inner peripheral side. The raceway surface 4a can come into contact with the rolling elements 6 at a nominal contact angle of 0° over the entire circumferential direction. The fitting surface 4b is formed in the shape of a cylindrical surface concentric with the fitting surface 1a of the shaft 1. As shown in FIG. The width (length in the axial direction) of the fitting surface 4b is constant along the entire circumference.

The fitting between the fitting surface 4b of the inner bearing ring 4 and the fitting surface 1a of the shaft 1 is set to tight fit with interference. The inner bearing ring 4 is fixed for rotation with the shaft 1 by its interference fit.

The outer bearing ring 5 is an annular bearing component having a raceway surface 5a extending in the circumferential direction on the inner peripheral side and a fitting surface 5b extending in the circumferential direction on the outer peripheral side. The raceway surface 5a can come into contact with the rolling elements 6 at a nominal contact angle of 0° over the entire circumferential direction.

The outer bearing ring 5 is loosely fitted with the housing 2 as a mating member, which is either one of the shaft 1 and the housing 2 .

3 and 4 show the shape of the bearing ring 5 in a natural state in which no load is applied to the outer bearing ring 5. FIG. The outer bearing ring 5 is composed of a main body 5c having a raceway surface 5a and a build-up member 5d having a fitting surface 5b.

A fitting surface 5b of the bearing ring 5 is formed in an arcuate shape. Its mating surface 5b defines the outer diameter of the outer bearing ring 5. As shown in FIG. The diameter of the fitting surface 5b corresponds to the diameter of an imaginary circle C that circumscribes the fitting surface 5b. The circular arc shape of the fitting surface 5b is set concentrically with the fitting surface 4b of the inner bearing ring 4 shown in FIGS. The width (length in the axial direction) of the fitting surface 5b is constant along the entire circumference.

The diameter of the fitting surface 5 b of the washer 5 is smaller than the diameter of the fitting surface 2 a of the housing 2 . The fitting surface 5 b of the outer bearing ring 5 and the fitting surface 2 a of the housing 2 are brought into contact with each other by a radial load F applied from the shaft 1 to the rolling bearing 3 .

Of the outer bearing ring 5 and the housing 2, only the outer bearing ring 5 has a flank 5e formed to divide the fitting surface 5b of the bearing ring 5 over the entire width. Since the flank 5e spans the entire width of the fitting surface 5b, it completely bisects the fitting surface 5b in the circumferential direction.

The flank 5e is formed in the shape of a groove extending in the axial direction by the annular main body 5c and the annular build-up member 5d having an end. The circumferential length of the flank 5e corresponds to the slit interval between the circumferential ends 5f, 5f of the padding member 5d, and can be defined by the angle α around the rotation center line of the shaft 1. Here, when the pitch angle between the rolling elements 6 shown in FIG. 1 is θ, the angle α corresponding to the circumferential length of the flank 5e shown in FIG. 3 is set to, for example, 0<α≦2θ. be able to. In order to suppress the deflection and stress of the bearing ring 5 due to the radial load F, it is preferable to set 0.5θ≦α≦θ.

The main body 5c is a bearing component integrally having a raceway surface 5a formed on the inner circumference and a cylindrical surface 5g formed on the outer circumference including a portion directly below the raceway surface 5a in the radial direction. As the main body 5c, for example, an outer ring for a standard deep groove ball bearing can be adopted. The cylindrical surface 5g of the main body 5c is composed of a surface portion extending in the circumferential direction over the entire circumference, and includes a cylindrical surface portion that defines the outer diameter of the main body 5c.

The build-up member 5d has a ring shape with ends, that is, a shape extending in a finite length in the circumferential direction. The padding member 5d is a molded part integrally having a fitting surface 5b formed on the outer diameter side and an overlapping surface 5h formed on the inner diameter side. The overlapped surface 5h is formed in an arcuate shape radially overlapping the cylindrical surface 5g of the main body 5c over the entire length in the circumferential direction. A circumferential end portion 5f of the padding member 5d has a planar shape extending radially and axially from the fitting surface 5b.

The padding member 5d may be formed using an appropriate material such as resin or metal and using a manufacturing method. The ring-shaped padding member 5 with ends as shown in the figure can be easily formed by pressing a thin metal plate, for example.

The padding member 5d has a radial interference with respect to the main body 5c. As shown in FIG. 4, the inner diameter d of the overlapping surface 5h in the natural state is set smaller than the outer diameter D of the cylindrical surface 5g of the main body 5c. The padding member 5d is fixed to the main body 5c by axially press-fitting it into the cylindrical surface 5g and the chamfered portion of the outer periphery of the main body 5c. When the padding member 5c is press-fitted, the main body 5c radially supports the padding member 5d as shown in FIG. be done. The flank 5e has a radial depth .delta. The radial depth δ corresponds to the radial distance between the virtual circle C and the flank 5e.

The fixing of the padding member 5d to the main body 5c is sufficient as long as both the members 5c and 5d can be integrated so that creep does not occur between the main body 5c and the padding member 5d.

For example, the padding member 5d formed in advance may be adhered to the main body 5c.

Further, by injection-molding the build-up member 5d onto the cylindrical surface 5g of the main body 5c, the formation of the build-up member 5d and the fixing of the build-up member 5d, which shrinks during molding, to the main body 5c by tightening are performed simultaneously. may

When the bearing ring 5 is loosely fitted to the fitting surface 2a of the housing 2 as a mating member, the flank 5e is formed between the bearing ring 5 and the fitting surface 2a of the housing 2, as shown in FIGS. A radial gap g is produced. Since the radial gap g is formed by the flank 5e dividing the full width of the fitting surface 5b that defines the outer diameter of the washer 5, the full width of fitting between the washer 5 and the housing 2 (fitting surface 5b (corresponding to the full width of the bearing ring 5), and the space axially penetrates between the outer circumference of the bearing ring 5 and the fitting surface 2a of the housing 2. As shown in FIG.

The flank 5e is formed so as to leave a radial gap g between the outer circumference of the bearing ring 5 and the fitting surface 2a of the housing 2 in the load bearing area when the maximum radial load F is applied to the rolling bearing 3. formed. Here, the maximum radial load F is the largest load within the fluctuation range of the radial load F applied to the rolling bearing 3 during operation of this bearing device.

In the rolling bearing 3 , the load bearing area that receives the radial load F extends approximately half the circumference of the rolling bearing 3 . The center of the load bearing area in the circumferential direction corresponds to the load direction of the radial load F (corresponding to the position on the extension of the radial load F in the arrow direction in FIG. 1). Since the raceway ring 5 receives a radial load on the raceway surface 5a via the rolling elements 6 in its load bearing zone, it undergoes elastic deformation. At this time, in the load bearing area of the rolling bearing 3, the fitting surface 5b and the flank surface 5e of the bearing ring 5 (especially the portion immediately below the raceway surface 5a) are deformed in a wavy shape. The wavy radial height is maximum at the circumferential center of the load bearing area and decreases with distance from the circumferential center.

The radial depth δ of the flank 5e shown in FIG. 3 is greater than the maximum radial height of the wave shape in the load bearing area of the rolling bearing 3 when the maximum radial load F shown in FIG. 1 is applied. set large.

As shown in FIG. 4, the maximum radial depth δ of the flank 5e shown in FIG. can be set to, for example, 0.005H≦δ≦0.1H, and the maximum radial depth δ of the flank face 5e is preferably set to 0.01H≦δ≦0.05H. This is for the purpose of suppressing deflection and stress of the bearing ring 5 due to the radial load F.

The radial gap g in FIGS. 1 and 2, the maximum radial depth δ in FIG. 3, and the thickness of the build-up member 5d in each drawing are exaggerated. In the wave-like deformation of the raceway ring 5 that actually occurs, the relative height of the wave-like shape with respect to the fitting surface 5b is generally on the order of several μm at maximum.

The outer bearing ring 5 is radially supported at a contact portion between a portion of the fitting surface 5b located within the load bearing range of the rolling bearing 3 shown in FIG. 1 and the fitting surface 2a of the housing 2. It will be. At the contact portion, a slightly wavy deformation portion of the fitting surface 5b contacts the fitting surface 2a. Even when the maximum radial load F is applied to the rolling bearing 3, the reaction force from the fitting surface 2a, which undergoes slight wave-like deformation at the aforementioned contact portion located in the load bearing zone, causes the bearing ring 5 to creep. It's not as powerful.

Since the radial clearance g shown in FIGS. 1 and 2 is formed by such a flank 5e, the outer bearing ring Even if the outer periphery (fitting surface 5b and flank surface 5e) of bearing ring 5 is deformed into a wavy shape, a radial gap g remains, and in the circumferential region where the radial gap g remains, the wavy deformed portion of the outer bearing ring 5 is formed. and the fitting surface 2a of the housing 2 cannot contact each other. That is, during the operation of this bearing device, the wavy deformed portion on the outer circumference of the outer bearing ring 5 does not come into contact with the fitting surface 2a of the housing 2 in the circumferential region where the radial gap g remains. Therefore, the wave-like deformation that occurs on the outer circumference of the outer bearing ring 5 in the load bearing zone of the rolling bearing 3 does not act as a traveling wave that causes the bearing ring 5 to creep. Therefore, compared to the case where the maximum elastic deformation portion (wavy deformation portion) of the bearing ring can contact the groove bottom and groove edge of the creep suppression circumferential groove as in Patent Document 1, this bearing device has a bearing ring 5 creep can be further suppressed.

Moreover, since this bearing device is formed by fixing the build-up member 5d to the main body 5c capable of radially supporting the build-up member 5d having the fitting surface 5b, the flank surface 5e is fixed to the raceway surface 5a. The main body 5c, which is a bearing component with be able to.

Further, in this bearing device, the main body 5c has a cylindrical surface 5g for supporting the build-up member 5d in the radial direction, and the build-up member 5d radially extends from the cylindrical surface 5g of the main body 5c with a finite length in the circumferential direction. , so that the flank 5e can be formed with a simple structure in which the end-connected annular padding member 5d is fixed to the cylindrical surface 5g of the main body 5c.

Further, in this bearing device, since the padding member 5d is press-fitted or injection-molded into the cylindrical surface 5g of the main body 5c, the padding member 5d can be fixed to the main body 5c by a simple means of press-fitting or injection/hardening. can.

Further, in this bearing device, out of the bearing ring 5 and the housing 2 which is the mating member of the clearance fit, only the bearing ring 5 has the flank 5e, and the main body 5c of the bearing ring 5 has the raceway surface 5a. Therefore, even if the flank 5e is located in a region different from the direction of the varying load, if the bearing ring 5 creeps to a certain extent (maximum one turn), the flank 5e will be Since the aforementioned radial gap g is formed in the load bearing region, creep of the bearing ring 5 can be suppressed thereafter.

If the direction of the radial load applied to the rolling bearing is a stationary load that does not fluctuate in the circumferential direction, a flank is formed only on the mating member to secure the radial clearance as described above, or It is also possible to form flanks on both the bearing ring and the bearing ring to secure the same radial clearance on both flanks. In the case of static load, it is possible to obtain a predetermined creep suppression effect by fitting the bearing ring and the mating member so as to create the aforementioned radial clearance at a position suitable for the load bearing region of the corresponding rolling bearing. be. However, when the flank is formed in the housing 2, which is a mating member, there is a concern that the creep suppression effect cannot be exhibited if the flank of the mating member is not arranged in the load bearing region by mistake. In order to avoid this, it is preferable to form the flank 5e only on the bearing ring 5. As shown in FIG.

Further, in this bearing device, it is the outer bearing ring 5 and the housing 2 that are loosely fitted, and the flank 5e is formed by the build-up member 5d and the main body 5c. Instead, the flank 5e can be formed by simple surface treatment to make the outer circumference of the bearing ring 5 non-circular. For example, if the housing is formed as part of a transmission case, the housing is molded. When the circumferential groove for creep suppression as in Patent Document 1 is formed in the housing, the circumferential groove becomes an undercut, making it difficult to manufacture the housing. Since the fitting surface 2a of the housing 2 does not need to have an undercut shape, the manufacturing of the housing 2 does not become difficult.

In this bearing device, the flank 5e is formed only on the outer bearing ring 5. The size may be appropriately determined in consideration of the rotational force applied to the bearing ring due to the contact between the fitting surface of the bearing ring and the fitting surface of the mating member in the load bearing zone.

For example, when the shaft and inner bearing ring are loosely fitted, at least one of the inner bearing ring and the shaft should have a flank. In this case, it is only necessary to reverse the relationship between the inside and outside of the embodiment. A padding member having an annular shape at the end may be fixed.

In the case of a static load, the flank may be formed only on the mating member, or may be formed on both the bearing ring and the mating member so as to secure the required radial clearance between the flanks facing each other. can be

Further, in this bearing device, an example is shown in which the flank 5e has a constant radial depth δ over substantially the entire circumferential length of the flank 5e. It is also possible to change the radial depth δ by reducing the radial thickness of the padding member. In the case of the illustrated example, since the maximum radial depth δ extends over substantially the entire length of the flank 5e in the circumferential direction, fine foreign matter does not reach the above-mentioned diameter compared to the case where the radial depth δ is varied. There is an advantage that it is difficult to accumulate in the direction gap g. On the other hand, if the surface pressure at which the boundary between the circumferential end portion 5f of the padding member 5d and the fitting surface 5b contacts the fitting surface 2a of the mating member due to excessive surface pressure, the surface pressure In order to suppress this, a chamfered change in thickness may be formed at the circumferential end portion 5f of the padding member 5d.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. Therefore, the scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and scope of equivalents of the scope of the claims.

1 shaft 2 housing (mating member)
2a Fitting surface 3 Rolling bearing 4 Inner bearing ring 5 Outer bearing ring (bearing ring)
5a raceway surface 5b fitting surface 5c body 5d build-up member 5e flank surface 5g cylindrical surface

Claims (4)

A shaft, a housing surrounding the shaft, and a rolling bearing interposed between the shaft and the housing, wherein the rolling bearing has a clearance fit with a mating member that is either the shaft or the housing. In a bearing device having a raceway ring, wherein the raceway ring and the mating member have fitting surfaces extending in a circumferential direction,
at least one of the bearing ring and the mating member has a build-up member having a fitting surface for the bearing ring or the mating member, and a main body that supports the build-up member in a radial direction;
A flank is formed so as to divide the fitting surface of the bearing ring or the mating member over the entire width by fixing the build-up member to the main body,
The at least one flank is configured to leave a radial gap between the bearing ring and the mating member in a load bearing range when the maximum radial load within the range of the radial load applied to the rolling bearing is applied. A bearing device characterized in that it is formed in the the main body has a cylindrical surface that supports the build-up member;
2. A bearing device according to claim 1, wherein said padding member is formed in an annular shape with ends radially overlapping the cylindrical surface of said main body with a finite length in the circumferential direction. 3. The bearing device according to claim 2, wherein the padding member is press-fitted or injection-molded onto the cylindrical surface of the main body. 4. A bearing device according to any one of claims 1 to 3, wherein only the bearing ring has the flank, and the main body of the bearing ring comprises a bearing component having a raceway surface.

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