JP5895462B2 - Sealed rolling bearing - Google Patents

Description

  The present invention relates to a sealed rolling bearing, and more particularly to a sealed rolling bearing used in a vibration load environment such as a railway vehicle.

  A rolling bearing unit for a railway vehicle is attached to an end portion of the axle of the railway vehicle, and rotatably supports the axle and supports the weight of the vehicle. FIG. 7 shows a conventional rolling bearing unit for railway vehicles.

  This rolling bearing unit for a railway vehicle includes a double row tapered roller bearing 10 (hereinafter referred to as a bearing 10) which is an example of a rolling bearing used in a railway vehicle, and the axle 20 of the railway vehicle supports the bearing 10. Has been. The bearing 10 includes an integrated outer ring 1 and inner rings 2 and 2 that are individually divided into rows, and a plurality of rollers (rolling elements) held by a cage 4 are provided between the inner ring 2 and the outer ring 1. ) 3 is arranged to roll freely. A rear lid (or backing ring) 6 and a front lid 7 are disposed at both axial ends of the bearing 10 so as to contact the side surfaces of the inner rings 2 and 2.

  On the outer peripheral side of the rear lid 6 and the front lid 7 near the bearings, a stepped cylindrical shield 31 is fitted and disposed on the outer ring 1. An annular seal 32 is attached to the inner peripheral side of the shield 31. That is, the outer peripheral side of the seal 32 is fixed to the inner peripheral surface of the shield 31, and the inner peripheral side of the seal 32 is in sliding contact with the outer peripheral surface of the rear lid 6 or the front lid 7. As a result, the bearing 10 is sealed, and dust, moisture, foreign matter, and the like are prevented from entering from the outside, and a lubricant such as grease in the bearing 10 is prevented from leaking to the outside.

  8A to 8C show various sealed rolling bearings to which the shield described in Patent Document 1 is attached. The shield 31 shown in FIG. 8A includes a cylindrical fixing portion 31a that is press-fitted and fixed to the inner peripheral surface 1a of the shoulder portion of the outer ring 1, and extends outward from the fixing portion 31a in the axial direction of the outer ring 1 and a seal 32. And a cylindrical holding portion 31b to be held. Further, a protruding portion 31c projecting in the radial direction is formed at the end portion of the fixed portion 31a, and engages with the seal groove 1b formed in the shoulder portion, thereby restricting the movement of the shield 31 in the axial direction. .

  Further, the shield 31 shown in FIGS. 8B and 8C has a tapered surface where the fixed portion 31a expands toward the tip, and the shoulder portion of the outer ring 1 is elastically reduced in diameter. Is fixed to the outer ring 1 by linearly contacting the annular corner portion 1c and the outer peripheral surface of the fixing portion 31a. Yes. In addition, a protrusion 31c that protrudes radially outward and engages with the seal groove 1b is formed at the tip of the fixed portion 31a.

JP 2008-240781 A

  By the way, when the shield of a rolling bearing is used in a vibration environment, particularly for a railway vehicle, it is necessary to set a large fitting allowance so that the shield does not fall off due to vibration. As a result, the outer ring is easily deformed by the installation of the shield, making it difficult to put the outer ring within a certain tolerance range. At the same time, even if the tolerance is secured, the outer ring and the housing will be in contact with each other. There was concern that fretting damage would occur on the outer peripheral surface.

  As a method to reduce the influence of deformation on the outer ring fitting portion with the housing, a method of providing relief on the outer ring outer peripheral surface corresponding to the shield mounting portion is generally adopted, but even in this case, it occurs due to the fit between the shield and the outer ring. When the force to be applied is large, the deformation also affects the outer ring outer peripheral surface other than the relief, and as a result, the outer ring outer peripheral surface contacting the housing may partially galling.

  Further, in the shield 31 shown in FIG. 8A, when the force generated by fitting is large, the deformation amount of the outer peripheral surface of the outer ring cannot be suppressed, so that the tightening margin cannot be increased so that the shield 31 falls off. There was a possibility. Further, in the shield shown in FIGS. 8B and 8C, since the fixed portion 31a is in line contact, the posture of the shield 31 is unstable, and stress concentration tends to occur on the contact surface. Moreover, since the outer peripheral surface of the fixing | fixed part 31a is a taper surface, it is hard to insert in the outer ring | wheel 1.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the shield from falling off and to suppress the deformation of the outer peripheral surface of the outer ring caused by the installation of the shield. It is an object of the present invention to provide a sealed type rolling bearing capable of suppressing variation in deformation amount.

The above object of the present invention can be achieved by the following constitution.
(1) It has an outer ring, an inner ring, and a plurality of rolling elements that are arranged so as to be able to roll between the outer ring and the inner ring, and a fixing portion that fits to the outer peripheral surface or inner peripheral surface of the outer ring. A shield,
In a sealed rolling bearing that supports an axle of a railway vehicle equipped with
The fitting allowance between the outer ring and the shield is such that the stress at the time of fitting at the corner between the fixed portion and the extending portion that is bent radially inward from the fixed portion is equal to or greater than the yield stress. Sealed type rolling bearing characterized by being set to.

  According to the sealed type rolling bearing of the present invention, the fitting allowance between the outer ring and the shield is set so that the stress at the fitting at the corner is equal to or higher than the yield stress, so that the allowable stress of the corner is within the allowable range. A large fitting allowance can be set to prevent the shield from falling off, and deformation of the outer peripheral surface of the outer ring caused by mounting the shield can be suppressed. Further, since the fluctuation of the generated stress due to the variation in the fitting allowance is smaller than that in the case of elastic deformation, the variation in the local deformation (warping) of the outer ring can be reduced.

It is a principal part expanded sectional view which shows the tapered roller bearing as a sealing type rolling bearing of this invention. It is a graph which shows typically the relation between the interference of the present invention and the amount of deformation of an outer ring. It is a principal part expanded sectional view which shows the deep groove ball bearing as a sealing type rolling bearing of this invention. (A) And (b) is a principal part expanded sectional view which shows the cylindrical roller bearing as a sealing type rolling bearing of this invention. (A) is a principal part expanded sectional view which shows the sealing type rolling bearing used for the test, (b) is a graph which shows the relationship between interference and an outer ring deformation amount. (A)-(c) is a principal part expanded sectional view which respectively shows the tapered roller bearing, deep groove ball bearing, and cylindrical roller bearing as a sealing type rolling bearing of this invention. It is sectional drawing of the conventional rolling bearing unit for rail vehicles. (A)-(c) is principal part sectional drawing which shows the conventional sealed type rolling bearing.

  Hereinafter, an embodiment of a sealed type rolling bearing according to the present invention will be described in detail with reference to the drawings. The sealed rolling bearing of the present invention can also be applied to the railway vehicle bearing unit shown in FIG. 7 described as the prior art, and parts substantially the same as or equivalent to the prior art are denoted by the same reference numerals in the drawings. The description is omitted or simplified.

  In the tapered roller bearing (sealed rolling bearing) 10 of the present embodiment, as shown in FIG. 1, a small diameter portion 1d is formed on the outer peripheral surface of the shoulder portion of the outer ring 1, and the outer peripheral surface 1e of the small diameter portion 1d. The inner peripheral surface of the fixing portion 31a of the shield 31 is fitted in The outer diameter of the small diameter portion 1d is set so that the outer peripheral surface of the shield 31 does not interfere with the housing when the outer ring 1 to which the shield 31 is attached is fitted in a housing (not shown).

  Further, the shield 31 has an extending portion 31 d that is bent and extended radially inward from the fixed portion 31 a so as to contact the axial end surface of the outer ring 1. Here, the small diameter portion 1d of the outer ring 1 and the fixing portion 31a of the shield 31 are fitted at a curved corner portion 31e (hereinafter referred to as a corner R portion 31e) between the cylindrical portion 31a and the extending portion 31d. The fitting allowance is set so that the stress is equal to or greater than the yield stress.

In this way, when the fitting allowance of the fitting surface with the outer ring 1 into which the shield 31 is inserted is set to be equal to or greater than the yield stress at the corner R portion 31e where the stress is concentrated, the relationship between the fitting allowance and the stress of the fitting portion. Is elasto-plastic, so the increase in the generated stress with respect to the increase in the fitting allowance is smaller than in the case of elastic deformation. As a result, the fitting allowance can be set large within the allowable range of the stress at the corner R portion 31e, and the fluctuation of the generated stress due to the variation in the fitting allowance is smaller than that in the case of elastic deformation. Variation in (sledge) can also be reduced.
The upper limit of the fitting allowance is a ratio of the interference / fitting portion outer diameter (the outer diameter of the small diameter portion 1d and the inner diameter of the fixing portion 31a) in consideration of the strength of the shield and the design interference range of the bearing for the railway vehicle. Therefore, it is set to 0.003.

  FIG. 2 schematically shows the effects of the present invention described above. In the interference d1 to d2, the outer ring deformation amount is A when the relationship between the fitting margin and the stress at the fitting portion is elastic, but when the relationship between the fitting margin and the stress at the fitting portion is elastoplastic, it is d1 or more. Since the stress at the corner R portion 31e is equal to or greater than the yield stress, the outer ring deformation amount is B, and the outer ring deformation amount can be significantly suppressed as compared with the case of elasticity.

  The sealed rolling bearing is not limited to the tapered roller bearing 10 shown in FIG. 1, but may be a deep groove ball bearing 10A shown in FIG. 3 or a cylindrical roller bearing 10B shown in FIG. The same effect can be obtained by setting the fitting allowance so that the fitting stress in Y is greater than the yield stress. In addition, as shown in FIG. 4A, the shield 31 may be provided with two extending portions 31d in a stepped shape, and as shown in FIG. 4B, the extending portion 31d is provided in one location. It may be provided.

FIG. 5 shows analysis values and actual measurement values when the present invention is applied to the cylindrical roller bearing of FIG. The bearing specifications are as shown in FIG. 5A, and the outer ring deformation amount is 14.5 mm from the shaft end. From the result shown in FIG. 5B, it is understood that the deformation amount (actually measured value) of the outer ring is greatly suppressed in a region where the stress at the corner R portion 31e is equal to or higher than the yield stress (interference of 0.1 mm or more). .
Note that a steel material such as SPCC is used as the shield 31 used for the railway vehicle, but SUS304 is used in the analysis and experiment of FIG.

  In addition, this invention is not limited to each embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

In the above embodiment, the case where the shield 31 is fitted to the outer peripheral surface of the outer ring 1 is shown. However, as shown in FIGS. 6A to 6C, the outer ring of the cylindrical roller bearing, the deep groove ball bearing, and the tapered roller bearing. The same effect can be obtained by setting the fitting so that the stress at the time of fitting at the corner R portion 31e of the shield 31 is equal to or higher than the yield stress on the inner peripheral surface 1a of the shoulder 1 of the first shoulder.
Moreover, as shown to Fig.6 (a), the protrusion part 31c which protrudes to radial direction outer side and engages with the seal groove 1b may be formed in the front-end | tip of the fixing | fixed part 31a.

  Moreover, although the shield 31 shown in FIG. 7 seals the bearing 10 by attaching the seal 32, the bearing 10 may be sealed by the shield 31.

DESCRIPTION OF SYMBOLS 1 Outer ring 1a Inner peripheral surface 1e Outer peripheral surface 2 Inner ring 3 Roller (rolling element)
10 Double row tapered roller bearing (sealed type rolling bearing)
10A Deep groove ball bearing 10B Cylindrical roller bearing 31 Shield 31a Fixing part 31d Extension part 31e Corner R part (corner part)

Claims (1)

An outer ring, an inner ring, and a plurality of rolling elements that are arranged to freely roll between the outer ring and the inner ring, and a shield having a fixing portion that fits together with an outer peripheral surface or an inner peripheral surface of the outer ring;
In a sealed rolling bearing that supports an axle of a railway vehicle equipped with
The fitting allowance between the outer ring and the shield is such that the stress at the time of fitting at the corner between the fixed portion and the extending portion that is bent radially inward from the fixed portion is equal to or greater than the yield stress. Sealed type rolling bearing characterized by being set to.

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