JP2003166548A - Sealing device of rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device of a rolling bearing which reduces wear of the lip by lessening the frictional resistance between the lip and the inner ring in the case of a high external pressure, and also reduces oil leakage as much as possible even in the case of a low external pressure. <P>SOLUTION: A plurality of ribs 522a extending along a curve toward the direction to form a recess opposite to the rotational direction of the inner ring 1 are formed on the face facing the annular space G of the bearing above the front end contiguous to the stepped side wall 11b of the inner ring 1 of the rib 52a. Thereby, the stream of a fluid like a lubricant oil or the like which has passed through between the rib 52a and the stepped side wall 11b of the inner ring 1 in a low external pressure is converted from a direction along the rotating direction R of the inner ring 1 to a stream f pushing back outside the annular space G by the contact with the rib 522a. By this motion, the external fluid is prevented from passing through between the lip 52a and the stepped side wall 11b of the inner ring 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing sealing device, and more particularly to a sealing device having excellent pressure resistance against pressure applied from the outside.

[0002]

2. Description of the Related Art For example, for bearings used in engine cranks such as buggies and transmissions, in order to efficiently pump lubricating oil to connecting rods and gear inners,
A bearing called a pressure resistant bearing is used.

That is, an example of a buggy transmission is shown in FIG.
Rolling bearing 6 supporting one end of the axle drive 61
An oil passage 63 for lubricating oil communicating with the oil pump is formed through the side surface on one side of No. 2, and the high-pressure lubricating oil supplied through this oil passage 63 passes through the oil passage 64 passing through the center of the axle drive 61. At the same time as being guided to the gear inner on the side of the axle drive 61, it is also guided to the gear inner on the side of the axle main via an oil passage 65 penetrating the axle drive 61 and communicating with the side of the axle main (not shown). Since the rolling bearing 62 is subjected to high pressure of the lubricating oil on one side surface of the rolling bearing 62, one side of the rolling bearing 62 is highly resistant to pressure so that the lubricating oil does not enter the rolling bearing 62. A bearing in which 62a is mounted, that is, a pressure resistant bearing is used.

The pressure-resistant seal bearing is a bearing excellent in pressure resistance against the pressure of a fluid such as lubricating oil outside the bearing as described above, and has a shape such as the shape of the inner ring with which the seal (sealing device) and its lip are in sliding contact. Various ideas have been made.

For example, in Japanese Utility Model Publication No. 6-19859, FIG.
In a rolling bearing in which a plurality of rolling elements 74 are rotatably arranged by a retainer 73 between an inner ring 71 and an outer ring 72, a step portion 711 is provided on the shoulder portion of the inner ring 71, and Lip 75 on the side wall 711a facing the outside of the bearing
2 so that the outer edge of the outer ring 72 is in sliding contact with the tip of
Is provided with a sealing device 75, and the core metal 751 of the sealing device 75 extends to a position facing the step side wall 711a that is a sliding contact partner of the lip 752, and the lip 752 slides against the step side wall 711a. Protects the lip 752 from external pressure at the rear part of the site, and
The cross-sectional shape of 2 has a substantially triangular shape in which the thickness in the axial direction is increased toward the center side in the radial direction so as to project inside the bearing, and is configured to be in line contact with the step side wall 711a. Give the tip of 752 sufficient flexibility,
In addition, the contact resistance to the inner ring 71 is reduced to suppress the increase of frictional resistance due to the increase of the external pressure to reduce the wear, and the pressure-resistant sealing of the bearing that can stably obtain the sealing effect for a long period of time. A device is disclosed.

In this type of pressure-resistant seal bearing, in order to further reduce the wear of the lip 752, as shown in FIG.
As shown in the front view of the main part of the vicinity of the lip 752 as seen from the inside of the bearing, the surface of the lip 752 that faces the inside of the bearing (inward of the annular space formed between the inner ring 71 and the outer ring 72) is A measure is taken to radially form a plurality of ribs 752a. Due to the presence of the ribs 752a, the sealing performance is slightly reduced, but the contact area with the inner ring 71 is reduced,
As compared with the case where the rib 752a does not exist, the amount of wear when the external pressure acts can be reduced. That is,
When the rib 752a does not exist, the inner ring 7 is acted upon by the external pressure.
The amount of wear of the lip 752 due to contact with 1 increases,
When the external pressure decreases, the gap between the inner ring 71 and the lip 752 becomes large, and as a result, the amount of oil leakage (the amount of oil on the high pressure side that passes through the sealing device, the same applies below) becomes large. Rib 7
By forming 52a, it is possible to reduce the frictional resistance of the lip 752 to the inner ring 71, thereby reducing the amount of wear of the lip 752 and eventually the amount of oil leakage.

[0007]

According to the structure in which the ribs 752a are radially provided as described above, the sealing property is improved by the elastic deformation of the lip 752 when the external pressure is high, but the external pressure is low when the external pressure is low. However, there is a problem that the amount of elastic deformation of the lip 752 and the rib 752a becomes small, the gap between the inner ring 71 and the lip 752 becomes large, and the amount of oil leakage becomes relatively large.

The object of the present invention is to reduce the frictional resistance between the lip and the inner ring when the external pressure is high to reduce the abrasion of the lip, and to reduce the oil leakage amount even when the external pressure is low. It is an object of the present invention to provide a rolling bearing sealing device that can be reduced in number.

[0009]

In order to achieve the above object, a rolling bearing sealing device of the present invention is a sealing device mounted on an axial end portion of an annular space formed between an inner ring and an outer ring of a rolling bearing. In the device, a lip made of an elastic material is integrally formed on at least the inner edge portion of the annular core metal, and the lip has a thicker wall in the axial direction toward the center side in the radial direction, and its maximum wall thickness portion. The outer edge portion is attached to the outer ring so that the distal end portion thereof contacts the side wall of the stepped portion formed in the shoulder portion of the inner ring facing outward. A plurality of ribs are formed on the facing surface, and each of the ribs is characterized by extending along a curved line facing the direction of rotation of the inner ring and becoming concave (claim 1).

Here, in the present invention, the curve along which each rib extends is a curve in which the outer peripheral side inclines toward the rear in the rotational direction of the inner ring with respect to the line extending radially from the bearing center (claim 2). ) Can be suitably adopted.

The present invention utilizes the function of the rib to reduce the frictional resistance by reducing the contact area of the lip with the inner ring when the external pressure is high, and by devising the shape of the rib, the external pressure is reduced. In this case, it is intended to have a function of suppressing oil leakage.

That is, when the external pressure is low,
Oil enters from between the lip and the inner ring, and the oil causes a flow in a direction that rotates in the rotational direction of the inner ring. In the present invention, the rib formed on the surface of the bearing facing the inner side of the annular space, which is located above the tip portion that is the contact portion with the stepped side wall of the inner ring, is formed with a recess facing the inner ring rotation direction. By extending along the curved line in a different direction, the oil entering the inside of the bearing while rotating with the rotation of the inner ring when the external pressure is small receives the force of being pushed back toward the outside of the bearing by hitting the rib. This makes it difficult for oil to pass through the sealing device, and it is possible to reduce the amount of oil leakage when the external pressure is small.

Further, as in the invention according to claim 2, by arranging each rib along a curved line in which the outer peripheral side is inclined rearward in the inner ring rotation direction with respect to a line extending radially from the bearing center, the inner ring is formed. It is possible to further enhance the effect of pushing back the oil that passes through the gap between the lip and the lip and rotates with the inner ring, and to further reduce the amount of oil leakage.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view parallel to an axis of a main part of an embodiment of the present invention, and FIG. 2 is a front view of the main part showing the vicinity of the tip of a lip 52a as viewed from the inside of a bearing.

The rolling bearing main body has an inner ring 1, an outer ring 2, and a plurality of balls (rolling elements) 3 arranged in an annular space G formed between them, and each of the balls 3 is constant in the circumferential direction. It is composed of a retainer 4 which is retained at intervals of.

The sealing device 5 has an annular shape as a whole, and includes a core metal 51 made of an annular metal plate and an elastic material 5 such as rubber.
2 is integrally formed, and a bent portion 51a that is bent toward the annular space G is formed on the outer peripheral portion of the cored bar 51. The elastic material 52 forms a lip 52a on the inner peripheral portion of the cored bar 51, and also forms a protruding portion 52b protruding outward from the bent portion 51a on the outer peripheral part of the cored bar 51. Then, the protruding portion 52b is fitted into the seal groove 21 formed on the inner circumference of the end portion of the outer ring 2 to be mounted on the rolling bearing.

A step portion 11 is formed on the shoulder portion of the inner ring 1, and the inner peripheral portion of the cored bar 51 faces the bottom surface (outer peripheral surface) 11a of the step portion 11 so as to be close to the bottom surface (outer peripheral surface) 11a. The lip 52a formed on the peripheral portion is in sliding contact with the surface 11b of the step portion 11 that faces the outside of the bearing (hereinafter referred to as the step portion side wall 11b).

The lip 52a is thicker in the axial direction on the radially inner side and has a substantially triangular cross-section, and the innermost end of the lip 52a on the annular space side is the inner ring. 1
It mainly comes into sliding contact with the step side wall 11b. A plurality of ribs 522a are formed on the outer peripheral surface of the tip portion T of the lip 52a, that is, the surface 521a of the lip 52a that faces the annular space G. Each rib 522a is
An outer peripheral side is inclined in a direction inclining rearward in the rotational direction R of the inner ring 1 with respect to a line L radially extending from the bearing center, which is indicated by a two-dot chain line in FIG. 2, and is opposed to the rotational direction R of the inner ring 1. Then, it extends along an arc-shaped curve curved in a concave direction. The cross-sectional shape of the rib 522a is not particularly limited, and may be, for example, a triangle, a semicircle, a rectangle, or the like.

In the above-described embodiment of the present invention, as shown in FIG. 4, the side surface on the mounting side of the sealing device 5 communicates with the discharge port of the oil pump or the like, and an oil passage through which high-pressure lubricating oil or the like flows. And so on. When the pressure in the oil passage or the like is high, the contact area of the lip 52a with the step side wall 11b is reduced due to the existence of the rib 522a, and thus the frictional resistance between them is reduced. The amount of wear of the lip 52a can be reduced, and a stable sealing function can be exhibited for a long period of time.

On the other hand, when the pressure in the oil passage or the like is low, the amount of elastic deformation of the lip 52a including the rib 522a is small, and the annular portion is formed between the stepped side wall 11a of the inner ring 1 and the tip T of the lip 52a. Lubricating oil or the like tries to enter into the space G, but the lubricating oil or the like rotates along with the rotation of the inner ring 1 to generate a flow in the same direction as the inner ring 1, and the flow is generated by each rib 52.
It hits the side surface of 2a. Since each rib 522a extends along a concave curve facing the rotation direction of the inner ring 1,
As shown by the arrow f in FIG.
It hits 22a and goes toward the stepped portion bottom surface 11a side of the inner ring 1, that is, to the outside of the annular space G. As a result, the amount of lubricating oil or the like passing between the lip 52a and the step side wall 11b can be reduced, and the amount of oil leakage can be reduced.

In the above embodiment, the ribs 522a are arranged such that the outer peripheral side of the rib 522a is inclined rearward in the rotational direction R of the inner ring 1 with respect to the line L extending radially from the bearing center. However, each rib 522a does not necessarily have to be tilted in that direction, and each rib 522a may be curved on the line L, as illustrated in FIG. However, Figure 2
By tilting the ribs 522a in the direction as shown in Fig. 5, a flow of the lubricating oil or the like can be surely directed to the outside of the annular space G, and the effect of reducing the amount of oil leakage can be further ensured. preferable.

[0022]

As described above, according to the present invention, the lip made of an elastic material provided on the inner peripheral portion of the core metal is made thicker in the axial direction toward the center in the radial direction, and the maximum thickness thereof is obtained. By installing the outer ring of the rolling bearing so that the thick end of the bearing contacts the outer side wall of the annular space of the step formed on the shoulder of the inner ring, fluid such as lubricating oil outside the bearing In a rolling bearing sealing device with improved pressure resistance against pressure, a plurality of ribs curved along a curve in a concave shape facing the rotation direction of the inner ring are formed on the surface of the lip facing inward of the annular space. Since it is formed, when the external pressure is high, the presence of the ribs can reduce the frictional resistance of the lip to the inner ring and prevent the lip from being worn.
When the external pressure is low, the flow of the fluid such as the lubricating oil passing between the lip and the step side wall of the inner ring in the direction in which the fluid rotates along with the inner ring is converted into the flow toward the outside of the annular space by hitting each rib. As a result, the fluid can be suppressed from flowing into the bearing.

Therefore, according to the present invention, the effect when the external pressure is high is the same as that of the conventional sealing device in which the radial ribs are provided on the surface of the lip that faces the inside of the bearing, and when the external pressure is low, the effect is the same. The amount of oil leakage can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view parallel to an axis of a main part of an embodiment of the present invention.

FIG. 2 is a front view of relevant parts showing the vicinity of the tip of the lip in FIG. 1 as viewed from the inside of the bearing.

FIG. 3 is a front view of a main portion showing the vicinity of the tip of the lip of another embodiment of the present invention as viewed from the inside of the bearing.

FIG. 4 is an explanatory view of a usage example of a pressure-proof sealed bearing, and is a cross-sectional view of a main part of a transmission such as a buggy.

FIG. 5 is a cross-sectional view of a main part of the conventional pressure-resistant sealed bearing, parallel to its axis.

FIG. 6 is a front view of a main part showing the vicinity of a lip 732 of FIG. 6 as viewed from the inside of the bearing.

[Explanation of symbols]

1 inner ring 11 steps 11a Step bottom 11b Step side wall 2 outer ring 21 seal groove Three balls 4 cage 5 Sealing device 51 core metal 52 Elastic material 52a lip 521a Face of the annular space G of the lip 522a rib

Claims (2)

[Claims] 1. A sealing device mounted on an axial end portion of an annular space formed between an inner ring and an outer ring of a rolling bearing, wherein a lip made of an elastic material is integrally formed on at least an inner edge portion of an annular core metal. The lip has a thicker wall in the axial direction toward the center of the radial direction, and the tip, which is the thickest part, is located outside the annular space of the step formed on the shoulder of the inner ring. The outer edge portion is attached to the outer ring so as to abut the facing side wall, and a plurality of ribs are formed on the surface of the lip facing inward of the annular space, and each rib faces in the rotational direction of the inner ring. The rolling bearing sealing device is characterized in that it extends along a curved line in a concave direction. 2. The curve along which the ribs extend is inclined with respect to a line extending radially from the bearing center such that the outer peripheral side is inclined rearward in the rotational direction of the inner ring.
The sealing device for a rolling bearing according to 1.