JP2002228006A - Oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive oil seal with simple structure and high sealability. SOLUTION: An outer cylinder 15 to which the oil seal 16 is attached has an large diameter portion 15b and a small diameter portion 15c are disposed adjacently to each other in the axial direction on its inner peripheral face. An inner diameter corner portion R of a step wall face 15a between the large diameter potion 15b and the small diameter portion 15c along the diameter direction is formed round. An annular core metal 18 has: a cylindrical portion 18b press-fitted in an inner periphery of the large diameter portion of the outer cylinder 15; and an annular plate portion 18a bent inward in the diameter direction and disposed to one axial end of the cylindrical portion 18b and allowed to abut on the step wall face 15a. The annular plate portion 18a is covered with an elastic body, which is brought into contact with the rounded inner diameter corner portion R of the outer cylinder 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal used for an axle bearing of a railway vehicle, for example.

[0002]

2. Description of the Related Art FIG. 6 is an enlarged sectional view showing a main part of an axle holding bearing device in a conventional railway vehicle.

[0003] The bearing device comprises a bearing 3 for supporting the axle 1,
A rear lid 9 (corresponding to a rotating shaft that rotates integrally with the axle 1) for fixing the bearing 3 in the axial direction and a sealed area including the end of the bearing 3 are sealed so that muddy water, dust, and the like can enter the bearing from the outside. An oil seal 8 for preventing intrusion.

The bearing 3 includes an outer ring 10, an inner ring 11, a double row tapered roller 12 between both wheels, and a retainer 13 for the tapered roller 12, and the inner ring 11 includes a rear lid 9, a front lid (not shown), Is fixed in the axial direction by being clamped in the axial direction.

[0005] The oil seal 8 projects from the outer race 10 of the bearing 3 to cover the entire circumference of the rear lid.
5 is provided with an annular core 18 press-fitted into the large diameter portion 15b, and a lip formed on the inner peripheral edge of the annular core 18.

[0006] This oil seal is provided in a state where the annular core 18 is press-fitted into the large-diameter portion 15 b of the outer cylinder 15.
The position in the axial direction is regulated by bringing the annular plate portion 18a of the annular core metal 18 into contact with the stepped wall surface 15a along the radial direction between the large diameter portion 15b and the small diameter portion 15c.

[0007] A tapered shape is formed on the inner peripheral edge of the annular plate portion 18a of the annular core bar 18 which is in contact with the stepped wall surface 15a of the outer cylinder 15 and is connected to the root of the lip toward the annular plate portion 18a. An elastic body G made of rubber was formed by bonding.

[0008] As shown in FIG.
The inner diameter corner R connected to the small-diameter cylinder 15c at the inner peripheral end of a is formed in a round shape, and the elastic body G is configured to simply approach the inner diameter corner R.

Therefore, in the oil seal 8, the annular core metal 18 and the outer cylinder 15 are press-fitted in a state where the metals are in contact with each other.

[0010]

The annular core 1
Since the metal is in contact with the outer cylinder 15, there is a small gap in the fitting surface between the outer cylinder 8 and the outer cylinder 15, and the inside of the sealed space in the bearing device is caused by the operation of rotating the shaft such as the axle. When the pressure rises, air escapes through a minute gap in the fitting surface between the annular cored bar 18 and the outer cylinder 15 and the function as a gasket is not sufficient. When the air is released, grease is also fitted. There was a risk of leakage to the outside through the surface.

Therefore, as shown in FIG. 6, by providing the pressure relief valve 30 on the outer ring member 15, when the internal pressure becomes high, the internal pressure is reduced by bleeding air through the pressure relief valve 30. It has also been proposed to prevent air and grease from leaking through a minute gap between the fitting surfaces of the annular core 18 and the outer cylinder 15.

However, in this case, the pressure relief valve 3
Since there is a problem in that the cost of parts and the manufacturing cost increase by providing 0 in the outer cylinder 15, an inexpensive structure that does not allow air to escape even if the internal pressure in the bearing increases without using the pressure relief valve 30 is desired. Had been rare.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as an object to solve the problem of obtaining an oil seal having a high hermeticity while having a simple structure and a low cost.

[0014]

SUMMARY OF THE INVENTION A first oil seal of the present invention axially partitions a rotating shaft disposed radially inward and outward and an opposed annular space of an outer cylinder, and is attached to the outer cylinder. An oil seal in which a lip that is in contact with the rotating shaft or is opposed to the rotating shaft via a minute gap is attached to an inner peripheral edge of the annular core metal, and an outer cylinder to which the oil seal is attached is an oil seal. The inner peripheral surface has a large-diameter portion and a small-diameter portion adjacent to each other in the axial direction, and has a shape in which an inner-diameter corner portion of a step wall surface along the radial direction between the large-diameter portion and the small-diameter portion is rounded, An annular core, a cylindrical portion press-fitted into the inner circumference of the large-diameter portion of the outer cylinder, and a radially inward annular portion provided at one axial end of the cylindrical portion and abutting against the stepped wall surface; A plate portion, and the annular plate portion has a round inner corner portion of the outer cylinder. Elastic body protruding to be brought into contact with is characterized in that it is deposited.

According to the first oil seal of the present invention, the cylindrical portion of the annular core is press-fitted into the large diameter portion of the outer cylinder, and the stepped wall surface along the radial direction between the large diameter portion and the small diameter portion of the outer cylinder. In a state in which the annular plate portion of the annular core is positioned so as to abut the opposed surface, the elastic body in the annular plate of the annular core is in close contact with the round inner corner of the outer cylinder. Therefore, there is no gap between the inside and outside at the fitting point between the annular core metal and the outer cylinder surface due to the elastic body.

Therefore, even if the internal pressure increases in the sealed space sealed by the oil seal, air can be prevented from escaping to the outside through the fitting portion between the annular core metal and the outer cylinder. Can be eliminated.

The second oil seal of the present invention is the same as the first oil seal of the present invention.
In the oil seal, the annular plate portion of the annular core metal,
A protruding elastic body that comes into contact with the step wall surface of the outer cylinder is attached.

According to the second oil seal of the present invention, since the elastic body that comes into contact with the stepped wall surface of the outer cylinder is attached to the annular plate portion of the annular core, the annular core is attached to the outer cylinder. When press-fitted, the elastic body of the annular plate portion comes into contact with the step wall surface, and together with the elastic body in contact with the inner diameter corner of the step wall surface, a sealed space sealed with an oil seal. In this case, even if the internal pressure increases, air can be prevented from escaping to the outside through the fitting portion between the annular core metal and the outer cylinder, thereby further improving the sealing performance.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIGS. 1 to 3 relate to an embodiment of the present invention. FIG. 1 is a side sectional view of a bearing device mounted on an axle of a railway vehicle, and FIG. FIG. 3 is a side sectional view showing an oil seal and the like.

In these figures, reference numeral 1 denotes an axle as an example of a shaft body which rotates with wheels (not shown) attached to the right side of FIG. The axle 1 has a journal 2, and a bearing 3 for holding the axle 1 is attached to the journal 2.

The illustrated bearing device A includes a bearing 3, a front lid 4, an oil draining sleeve 5, a plurality of bolts 6, sealing devices 7, 8 on the free end side and the wheel side, and a rear lid. 9 (corresponding to a rotating shaft).

The bearing 3 is a so-called hermetically sealed double row outward tapered roller bearing which is disposed outward, and has an outer ring 10, an inner ring 11, and a double row tapered roller 12 as a rolling element between the two wheels 10, 11. And a retainer 13 for the tapered rollers 12 and an inner ring spacer 14.

The outer ring 10 is fixed to an axle housing of a railway vehicle (not shown).

The inner race 11 is held between the front cover 4 and the rear cover 9 in the axial direction, whereby the entire bearing 3 is fixed immovably in the axial direction.

In this case, the front cover 4 and the rear cover 9 are arranged on the outer periphery of the journal portion 2 of the axle 1 on both sides in the axial direction. That is, the front cover 4 abuts on the free end side end surface of the inner race 11 via the oil draining sleeve 5, and the rear cover 9 directly abuts on the wheel end surface of the inner race 11, and the bearing 3 is moved in the axial direction. It is an annular fixing member that is fixed immovably.

In this case, the front lid 4 is fixed to the journal 2 by tightening the bolt 6 with a predetermined torque.
And is in contact with the free end side end of the inner race 11 via the oil draining sleeve 5.

Although the rear lid 9 has a structure integrated with the oil draining sleeve, the rear lid 9 may be in contact with the wheel-side end surface of the inner race 11 via the oil draining sleeve, similarly to the front lid 4 side. .

The sealing devices 7 and 8 are disposed on the outer peripheral surfaces of the front cover 4 and the rear cover 9 on both sides of the bearing 3 in the axial direction, respectively, to prevent the inside of the bearing 3 from entering.

The structure of the wheel side sealing device 8 will be described. The sealing device 7 has the same structure as the sealing device 8 according to the present invention, and a description thereof will be omitted.

The sealing device 8 includes a metal case 15 as an outer cylinder and an oil seal 16.

The case 15 has a cylindrical shape with a step in the axial direction, one end of which is attached to the inner peripheral end of the outer race 9, and the other end of which is not in contact with the annular groove 17 of the rear lid 9. The labyrinth is built in to form.

That is, the case 15 has a large-diameter portion 15b and a small-diameter portion 15c on its inner peripheral surface adjacent to each other in the axial direction, and a step along the radial direction between the large-diameter portion 15b and the small-diameter portion 15c. The inner diameter corner R of the wall surface 15a is formed round,
In other words, the radial cross-sectional shape of the surface facing the oil seal 16 side at the corner transitioning from the step wall surface 15a to the small diameter portion 15c is formed so as to form a curved surface.

The oil seal 16 is fitted to the large diameter portion 15b of the case 15, as will be described later in detail.

The oil seal 16 includes an annular core 18 having an approximately L-shaped upper half cross section along the inner periphery of the case 15, and a cylindrical portion fitted to the large diameter portion 15 b of the case 15 of the annular core 18. An elastic body 19 made of rubber is attached to the inner peripheral portion of the annular plate portion 18a provided as a surface along the radial direction at one axial end of the 18b.

A main lip 19a as an axially adjacent lip and two auxiliary lips 19b and 19c are formed at the inner peripheral end of the elastic body 19.

The main lip 19a has a garter spring 20
And the inner peripheral side thereof is in sliding contact with the outer periphery of the rear lid 9.

The oil seal 16 further has a slinger 21 made of metal. The slinger 21 has a cylindrical portion 21 press-fitted onto the inner periphery of the cylindrical portion 18b of the annular cored bar 18.
b, which is provided at one axial end of the cylindrical portion 21b and substantially in parallel with the annular plate portion 18a of the annular core bar 18 at a required interval in the axial direction and has a minute distance from the outer peripheral surface of the rear cover 9. And an annular plate portion 21a which is opposed via a gap.

The space between the annular plate portion 21a and the main lip 19a in the axial direction forms a lubricant holding space 22. The lubricant composed of grease is shown by cross hatching.

The lubricant is held not only in the lubricant holding space but also between the lips 19a to 19c.

The other end of the slinger 21 is in axial contact with the annular core 18. With this structure, the slinger 21 can be used as a receiving member of a mounting jig when the oil seal 16 is mounted inside the case 15 in the axial direction.

Next, features of the present invention will be described. As shown in FIGS. 1 to 3, in the oil seal 16, as described above, the fitting to the case 15 is performed by the cylindrical portion 18 b of the annular core 18 and the annular core 1
8 is a stepped wall surface 15a of the case 15
Abutment is regulated.

Therefore, oil is applied to an inner corner formed by the inner peripheral surface of the large diameter portion 15b along the axial direction of the case 15 and the step wall 15a formed radially inward from the large diameter portion 15b. The annular core 18 of the seal 16 is fitted and mounted. The fitting width in the axial direction between the annular core 18 and the cylindrical portion 15b of the case 15 (the annular core 18
And the cylindrical portion 15b are in contact with each other) is 10.8 m
m, and the fitting force is 1400 kgf as a calculated value.

Furthermore, the annular plate portion 1 of the annular core 18
An elastic body 23 is formed on the surface facing the stepped wall surface 15a in 8a in the same material as the auxiliary lip 19c and the like so as to be continuous.

The elastic body 23 is formed with a ridge 23a which forms a strip over the entire circumference around one axis of the axle, and the ridge 23a is formed on the inner diameter corner R of the stepped wall surface 15a.
In the axial direction.

When the oil seal 16 is fitted to the case 15, the ridge 23a is in close contact with the inner corner R in a compressed state.

Further, the sealing elastic body 23 is provided with a flat contact portion 23b which is bonded to the annular plate portion 18a so as to form a flat surface radially outward of the ridge portion 23a.

The thickness of the flat contact portion 23b is set so as to be closer to the annular plate portion 18a than the ridge portion 23a projecting toward the step wall surface 15a.
Is fitted to the case 15, the step wall 15a
And in close contact with it in a compressed state.

That is, the elastic body 23 has the protruding ridge 23a at the inner diameter corner portion R and the annular plate portion 18a with respect to the stepped wall surface 15a.
Since the flat contact portions 23b protruding from the stepped wall surface 15a are in close contact with the flange surface F, close contact for sealing is made at two locations in the radial direction. Sealability is high.

The inventor conducted a sealing evaluation test using the sealing structure of the first embodiment.

That is, as shown in FIG. 5, with the case 15 and the oil seal 16 mounted on the test jig J, high-pressure air is supplied from the air source A into the sealed space S, The test was performed so that the air pressure could be confirmed by the pressure gauge 25.

Specifically, the internal pressure of the bearing device is previously set to 40 k
When the pressure was set to Pa (equivalent to several times the normal internal pressure of the oil seal in the axle bearing device of the railway vehicle) and the internal pressure was changed after 5 minutes, no pressure change was found. Was.

For comparison, a similar sealing performance evaluation test was performed using a conventional sealing structure. For the conventional sealing structure, the internal pressure of the bearing device is previously set to 10 kPa (corresponding to the normal internal pressure of the oil seal in the axle bearing device of a railway vehicle).
Was left for 5 minutes in the state set in, when the change of the internal pressure after 5 minutes was confirmed, a pressure drop was recognized,
Air leakage was confirmed.

(Embodiment 2) Next, another embodiment of the present invention will be described. It should be noted that this another embodiment is also an oil seal for axle of a railway vehicle as in the above-described first embodiment, and the same structures are denoted by the same reference numerals and description thereof is omitted.

FIG. 4 is a side sectional view showing an oil seal and the like according to the second embodiment.

The sealing device 8 together with the case 15 as an outer cylinder
The oil seal 16 has an annular cored bar 18 fitted and mounted on the inner peripheral surface of the large-diameter portion 15b forming the step portion of the case 15.

The upper half cross-sectional shape of the annular core 18 along the inner periphery of the case 15 is substantially L-shaped, and the annular plate portion 18a of the annular core 18 along the radial direction is When the oil seal 16 is fitted and mounted on the case 15, the annular plate portion 18a is restricted in the axial direction by the step wall surface 15a. The annular core 18 and the cylindrical portion 1 of the case 15
The fitting width in the axial direction with respect to 5b (the width at which the annular core metal 18 and the cylindrical portion 15b are in contact with each other by fitting) is 6.6 mm,
The fitting force is 950 kgf as a calculated value.

An elastic member 19 made of rubber is attached to the inner peripheral portion of the annular plate portion 18a, and the inner peripheral end of the elastic member 19 has a main lip 1 as a lip that is adjacent in the axial direction.
9a and two auxiliary lips 19b and 19c.

As a characteristic part of the present invention, the surface of the annular core portion 18 facing the stepped wall surface 15a of the annular plate portion 18a includes:
The elastic body 24 is formed of the same material as the auxiliary lip 19c and the like so as to be continuous.

As shown in FIG. 4, the elastic body 24 is provided with a ridge 24a and a ridge 24b so that the elastic body 24 faces the inner corner R at the radially inner end of the step wall 15a in the axial direction. Respectively.

The ridges 24a and the ridges 24b are formed so as to be located at two radially inner and outer locations, respectively, and the ridges 24a protrude from the ridges 24b in the axial direction. In a state fitted and mounted on the inner peripheral portion 15, the ridge portion 24 b comes into close contact with a radially inner side position of the inner diameter corner portion R in a compressed state, and the ridge portion 24 b is in a compressed state with respect to the inner diameter corner portion R at a radially outer position therefrom. In close contact.

In each of the above-described embodiments, the elastic body that comes into contact with the inner corner of the stepped wall surface of the outer cylinder is provided integrally with the lip on the annular core, but the annular core is provided separately from the lip. And the elastic body abuts against the stepped wall portion of the outer cylinder or the inner diameter corner portion at a plurality of positions in the radial direction,
Each elastic body may be provided on the annular core in a state of being separated from each other at each contact point.

As the member corresponding to the rotating shaft, in the above-described embodiment, a structure such as a rear lid separate from the axle is shown, but the axle itself may be used.

[0064]

As described above, according to the first aspect of the present invention, the cylindrical portion of the annular core is press-fitted into the large diameter portion of the outer cylinder, and the diameter between the large diameter portion and the small diameter portion of the outer cylinder is adjusted. In a state in which the annular plate portion forming the opposite surface of the annular core is positioned so as to abut against the stepped wall surface along the direction, the elastic body in the annular plate portion of the annular core has a round inner corner of the outer cylinder. Because of the elastic body, there is no gap between the inside and outside at the fitting point between the annular core metal and the outer cylinder surface.

For this reason, even if the internal pressure increases in the sealed space sealed by the oil seal, air can be prevented from escaping to the outside through the fitting portion between the annular core and the outer cylinder. Can be eliminated.

Therefore, the annular core having the lip can be easily sealed with a simple structure in which the annular core is fitted to the outer ring member, and the need for a separate pressure relief valve or the like can be eliminated. Inexpensive configuration.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a bearing device according to an embodiment of the present invention mounted on an axle of a railway vehicle.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a side sectional view showing the oil seal according to the first embodiment;

FIG. 4 is a side sectional view showing an oil seal according to a second embodiment.

FIG. 5 is a schematic view showing a test for evaluating sealing performance of the oil seal according to the present invention.

FIG. 6 is an enlarged view of a main part of a conventional oil seal.

[Explanation of symbols]

 9 Rear lid (rotating shaft) 15 Case (outer cylinder) 15a Step wall surface 15b Large diameter portion 15c Small diameter portion 16 Oil seal 18 Ring core 18a Ring plate 18b Cylindrical portion 19a, 19b, 19c Lip 21 Slinger 21a Ring plate 23 , 24 Elastic body R inner diameter corner

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahide Sunagawa 39, Nishino, Kasagi, Aizumi-cho, Itano-gun, Tokushima Pref. Koyo Sealing Techno Co., Ltd. F-term (reference) 3J006 AA01 AE04 AE08 AE17 AE23 AE40

Claims (2)

[Claims] 1. A rotary shaft disposed radially inward and outward and an annular space facing an outer cylinder which is partitioned in an axial direction, and an inner peripheral edge of an annular core bar attached to the outer cylinder is provided with respect to the rotary shaft. An oil seal comprising a lip which is brought into contact with or opposed via a minute gap, and an outer cylinder to which the oil seal is attached has a large diameter portion and a small diameter which are axially adjacent to the inner peripheral surface thereof. And the inner wall of the stepped wall along the radial direction between the large-diameter portion and the small-diameter portion is formed into a round shape, and the annular core metal has a large-diameter portion inner periphery of the outer cylinder. A cylindrical portion that is press-fitted into the cylindrical portion, and a radially inward annular plate portion provided at one axial end of the cylindrical portion and in contact with the step wall surface. A projecting elastic body that is brought into contact with the round inner corner of the outer cylinder is attached. It is, oil seal, characterized in that. 2. The oil seal according to claim 1, wherein a protruding elastic body that contacts the stepped wall surface of the outer cylinder is attached to the annular plate of the annular core. An oil seal characterized by the following.