JP3356540B2 - Axle bearings for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vehicle axle bearing used for a railway vehicle, an industrial bogie, and the like.

[0002]

2. Description of the Related Art As shown in FIG. 2A, this type of vehicle axle bearing has a wheel (2) fitted to a large diameter portion inside a predetermined dimension from an end of an axle (1) by interference fitting. The double-row rolling bearing (3) is inserted and fixed in the small diameter portion at the end of the axle (1) with the seal ring (4) arranged on the shoulder side of the axle, and the ring is tightened from the shaft end toward the axle shoulder. It is tightened and fixed in (5).
FIG. 2A is a cross-sectional view of the upper half at one end of the axle (1), and both ends have the same structure. In this structure, the cantilever and the large impact load cause the axle (1) to bend (ρ) as shown by a chain line in FIG. ), A load is repeatedly applied to the inner diameter surface corner of the inner ring (3a), particularly the inner diameter surface corner (a) of the end surface on the side of the seal ring (4), and fretting wear occurs on the axle (1). . It is desirable to prevent the fretting wear from causing a decrease in the strength of the axle (1). Therefore, conventionally, chamfering is performed on the inner diameter surface corner (a). As shown in FIG. 2B, the conventional chamfer angle γ is set to γ = 10 ° to 20 °, and the surface roughness is set to about 12S.

[0003]

Recently, it has been found that the conventional measures against fretting wear are not sufficient because the use conditions have become severe due to the demand for higher speeds of Shinkansen bullet trains and the like. It has been found that fretting wear is likely to occur on the axle (1) near the intersection (boundary point) between the inner diameter surface corner (a) and the inner ring (3a) inner diameter surface. As a result of studying the cause, since the conventional chamfer angle γ was set to γ = 10 ° to 20 °, the intersection (boundary point) becomes a corner and the surface roughness is 12
It is presumed that coarseness of about S promotes fretting wear.

It is an object of the present invention to provide a vehicle axle bearing which can suppress fretting wear even under severe use conditions.

[0005]

In order to achieve the above object, the present invention provides a double-row rolling bearing having a small diameter portion at the end of an axle in which a wheel is tightly fitted to a large diameter portion inside a predetermined dimension from the shaft end. In a vehicle axle bearing in which a seal ring is arranged and inserted on the shoulder side and fastened and fixed with a tightening ring from the shaft end toward the shaft shoulder, a chamfer angle γ at the end of the inner ring inner diameter surface end of the double row rolling bearing is γ ≦ A 7 ° chamfered portion is provided, and the radius of curvature R at the intersection (boundary point) between the chamfered portion and the inner ring inner diameter surface is R ≧
An arc portion having a diameter of 5 mm is formed, and the surface roughness of the chamfered portion is set to 6S or less.

[0006]

According to the present invention, a chamfer angle γ of a chamfered portion provided at an inner ring inner surface end of a double-row rolling bearing in a vehicle axle bearing is reduced to γ ≦ 7 °. At the intersection (boundary point) of which the radius of curvature R is R ≧ 5 mm and the surface roughness of the chamfered portion is reduced to 6S or less, so that the contact stress causing fretting wear can be reduced. Decentralize and reduce,
Friction can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional view of an upper half of one end of an axle of a vehicle axle bearing to which the present invention is applied,
FIG. 1B is an enlarged sectional view of a main part.

In FIG. 1A, (1) is an axle,
(2) shows a wheel, (3) shows a double row rolling bearing, (4) shows a seal ring, and (5) shows a tightening ring.

The axle (1) has a large-diameter portion (1a) inside a predetermined dimension from the shaft end, and the large-diameter portion (1a) has a wheel (2).
Are fitted and fixed by an interference fit. At the end of the axle (1), there is a small-diameter portion (1b), and a shoulder (1c) is formed at the boundary between the small-diameter portion (1b) and the large-diameter portion (1a). Further, a screw portion (1d) for screwing the tightening ring (5) is formed in the shaft end of the axle (1).

The double-row rolling bearing (3) is fitted with a seal ring (4) arranged on the small-diameter portion (1b) of the axle (1) on the side of the shaft shoulder (1c), and the shaft shoulder from the shaft end. Toward (1c), it is fastened and fixed with a fastening ring (5).

The double row rolling bearing (3) has two rows of inner rings (3a), (3a), an integrated outer ring (3b), two rows of tapered rollers (3c), (3c), and a cage ( (Illustration is omitted), the double-row tapered roller bearing is illustrated, but a double-row cylindrical roller bearing may be used.

The inner race (3a) of the double row rolling bearing (3)
As shown in FIG. 1 (B), a chamfered portion (b) having a chamfering angle γ of γ ≦ 7 ° is provided at the end of the inner diameter surface, and the chamfered portion (b) and the inner ring inner diameter surface (c) are provided. Is formed at the intersection (boundary point) with a radius of curvature R of R ≧ 5 mm,
Further, the surface roughness of the chamfered portion (b) is set to 6S or less.

Except for the above conditions, the effect of suppressing fretting wear is not sufficient. For example, when the chamfer angle γ is set to 7 ° or more, the angle of the corner formed at the intersection (boundary point) between the chamfered portion (b) and the inner ring inner diameter surface (c) increases, and the axle (1) side due to this corner portion Tend to increase the contact stress. When the radius of curvature R of the arc portion (d) formed at the intersection (boundary point) between the chamfered portion (b) and the inner ring inner diameter surface (c) is 5 mm or less, the contact stress on the axle (1) side increases. Tend to. Further, when the surface roughness of the chamfered portion (b) is 6S or more, the effect of reducing the frictional force cannot be sufficiently expected. Although these conditions can be expected to have a considerable effect even when used alone, a remarkable effect of suppressing fretting wear can be obtained by summing up the respective conditions. The embodiment of the drawings illustrates a case where the measure for suppressing fretting wear in the present invention is applied to the end on the seal ring (4) side, but the same measure is applied to the end on the tightening ring (5) side. It is desirable to apply also.

[0014]

According to the present invention, the chamfer angle γ of the chamfer provided at the end of the inner ring inner surface of the double row rolling bearing in the vehicle axle bearing is reduced to γ ≦ 7 °, and At the intersection (boundary point) with the inner ring inner diameter surface, the curvature radius R is
By forming an arc portion with ≧ 5 mm and further reducing the surface roughness of the chamfered portion to 6S or less, the contact stress on the axle side with respect to the inner ring inner diameter surface end of the double row rolling bearing is dispersed and reduced. In addition, since the frictional force can be reduced by improving the smoothness of the surface roughness, fretting wear in the above-described portion can be suppressed.

[Brief description of the drawings]

FIG. 1A is a sectional view of an upper half of one end of an axle of a vehicle axle bearing to which the present invention is applied, and FIG. 1B is an enlarged sectional view of a main part.

FIG. 2A is a cross-sectional view of an upper half of one end of an axle of a conventional vehicle axle bearing, and FIG. 2B is an enlarged cross-sectional view of an inner-ring inner diameter surface end corner portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axle 2 Wheel 3 Double row rolling bearing 4 Seal ring 5 Tightening ring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 33/58-33/64 F16C 19/34-19/38 B61F 15/12

Claims (1)

(57) [Claims] 1. A double-row rolling bearing is disposed on a small diameter portion at the end of an axle in which a wheel is tightly fitted to a large diameter portion inside a predetermined dimension from a shaft end, and a seal ring is disposed on a shaft shoulder side and fitted and inserted. In a vehicle axle bearing that is tightened and fixed with a tightening ring toward the shaft shoulder, the chamfering angle γ is γ ≦
A chamfered portion having a radius of curvature of R ≧ 5 mm is formed at the intersection (boundary point) between the chamfered portion and the inner ring inner surface, and the surface roughness of the chamfered portion is further increased. The vehicle axle bearing is characterized by having a length of 6S or less.