JP2003314574A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assuredly prevent metallic abrasion powder from moving to the bearing sealing area of a bearing unit with a simple and inexpensive structure. <P>SOLUTION: In the structure in which a rear cover 6 axially abuts on the inner ring 11B of a rolling bearing 3, a step 9 whose diameter is reduced toward the inner ring 11B of the rear cover 6 is provided. While the diameter of a paking 10 is elastically reduced relative to the step 9, the packing 10 is externally fitted to the step 9. A first protruding piece 32a and the third protruding piece 32c provided in an elastic member 32 of the packing 10 are allowed to come into contact under pressure with the outer end face of the second inner ring 11B. Thus, since the outside diameter side of the abutting surface of the rear cover 6 and the second inner ring 11B is closed by the packing 10, the metallic abrasion powder generated in the abutting surface is sealed within the abutting surface. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing unit used for supporting a shaft body.

[0002]

2. Description of the Related Art A bearing unit used for supporting an axle of a railroad vehicle will be briefly described with reference to FIG. 1 presented in the embodiment. In the figure, 1 is an axle, and 2 is a bearing unit. The bearing unit 2 includes a rolling bearing 3, a front cover 4, an oil draining sleeve 5, a rear cover 6, and sealing devices 7 and 8.

The rolling bearing 3 is a double row tapered roller bearing. The two inner rings 11A, 11 provided in the rolling bearing 3
The rolling bearing 3 is positioned in the axial direction by sandwiching B in the axial direction between the front lid 4, the oil removing sleeve 5, and the rear lid 6.

[0004]

In the above-mentioned conventional example, since the vehicle shaft 1 is repeatedly subjected to radial and axial loads, shocks, and vibrations, a small amount of flexure is repeatedly generated.
Both are contact surfaces of the metal rear lid 6 and the second inner ring 11B,
So-called fretting may occur and fine particles of metal abrasion powder may occur.

When such metal abrasion powder comes out of the contact surface and moves toward the sealing device 8 and the rolling bearing 3, the lip sliding surface of the sealing device 8 and the tapered roller 13 of the rolling bearing 3 are There is a risk of biting between the outer rings 11 and 12, which may shorten the life of the rolling bearing 3 and the sealing device 8.

[0006]

On the other hand, the inventors of the present invention provided a groove on the end face of the rear lid in order to confine the metal abrasion powder generated at the contact portion on the contact surface, and On the other hand, I thought about installing an O-ring. This O-ring is generally commercially available and inexpensive, but it has the drawback that it can be easily removed from the groove and that leakage of metal abrasion powder cannot be reliably prevented. In view of such circumstances, the present invention has been proposed.

The bearing unit according to the present invention has a rolling bearing externally fitted to the shaft body and having at least an inner ring, and an outer periphery of the rolling body which is in contact with one end surface of the inner ring of the rolling bearing in the axial direction. It has a ring body for axially positioning the rolling bearing by being fitted and mounted, and a sealing device which is arranged on the outer periphery of the ring body and closes one axial end of the rolling bearing. A stepped portion having a small diameter is provided near the inner ring of the rolling bearing in the annular body, and the packing is externally fitted to the stepped portion while being elastically reduced in diameter. The packing has a structure in which an elastic body is covered with a spring ring as a core material, the spring ring is arranged near an inner corner of the step portion, and the elastic body is pressed against the end surface of the inner ring.

The shaft body is rotated or non-rotated. When the shaft body is rotated, the inner ring and the ring body of the rolling bearing also rotate together with the shaft body, and the outer ring of the rolling bearing does not rotate. When the shaft body is not rotated, the inner ring and the ring body of the rolling bearing are also not rotated, and the outer ring of the rolling bearing or a member that can be the outer ring is rotated.

Examples of the above-mentioned spring ring include those in which coil springs are connected in a ring shape, and a circlip in which one circumference is separated. The elastic body means NBR, hydrogenated NB
In addition to rubber materials such as R, acrylic rubber, and fluoro rubber, elastomers (polymer substances having elasticity at room temperature) and the like can be mentioned.

In the above structure, since the elastic body of the packing is pressed against the end surface of the inner ring, even if fretting occurs on the contact surface between the inner ring and the ring body and metal wear powder is generated, The metal abrasion powder is prevented from going outward in the radial direction from the contact surface. The above-mentioned metal abrasion powder is generated by the sliding of metal materials, and means that the metal components are contained in the contained components regardless of the content ratio.

The packing is formed by covering the elastic body with the spring ring as the core material, and the spring ring is arranged in the state of being elastically reduced in diameter near the inner corner of the stepped portion of the ring body. Is attached to the step portion while being tightly tightened, so that this packing is unlikely to fall off the step portion.

By the way, the rolling bearing has two inner rings fitted to the shaft body axially adjacent to each other and each having one row of raceway surfaces, and each of the two inner races is individually radial in the radial direction. A single outer ring having opposing two rows of raceway surfaces, and a plurality of rolling elements respectively interposed between the two rows of raceways of the outer ring and the respective one row of raceways of the inner rings It is configured as The sealing device includes a case attached to one end of the outer ring of the rolling bearing in the axial direction to surround the outer circumference of the ring body, and an outer peripheral surface of the ring body on an annular core metal fixed to the inner circumference of the case. A seal ring formed by applying a radial lip that is in contact with a region axially outward of the step portion, and a radial lip attached to an annular core of the seal ring and on the outer peripheral surface of the annular body. A metal ring facing the area between the packing and the packing via a minute gap is provided.

This configuration specifies the configurations of the rolling bearing and the sealing device, which are the main constituent elements of the present invention,
If metal abrasion powder is mixed in, it is not preferable in terms of function.

Further, the cross section of the upper half of the packing is
It is formed in a substantially rectangular shape, and in this packing, the spring ring is covered with an elastic body in a state of being arranged at one end in the axial direction on the inner diameter side, and in the elastic body, the other end side in the axial direction of the spring ring. And a recess is provided on the outer diameter side.

In this structure, the outer shape of the packing itself is simple, and an elastic body is vulcanized and adhered to the spring ring.
Since it can be mass-produced, the cost can be reduced.

[0016]

1 to 3 show an embodiment of the present invention. In the figure, 1 is an axle of a railway vehicle or the like, and 2 is a bearing unit.

Although not shown, the axle 1 is rotationally driven with wheels mounted on the right side of FIG. The axle 1 has a journal portion 1a, and the bearing unit 2 is mounted on the journal portion 1a.

The bearing unit 2 includes a rolling bearing 3, a front lid 4, an oil draining sleeve 5, a rear lid 6, and sealing devices 7 and 8.
With.

The rolling bearing 3 is a double row outward tapered roller bearing, and is externally fitted and mounted on the journal portion 1a of the axle 1. The rolling bearing 3 has a journal portion 1a of the axle 1.
And two inner rings 11A and 11B that are fitted to each other axially side by side and each have one row of raceway surfaces, and these two inner rings 11
A single outer ring 12 having two rows of raceway surfaces that individually oppose each raceway surface of A and 11B in the radial direction, and this outer ring 12
A plurality of tapered rollers 13 respectively interposed between the two rows of raceway surfaces and the respective one row raceways of the inner rings 11A and 11B,
It includes a retainer 14 and a spacer 15. The outer ring 12 is
It is fixed to the vehicle body of a railroad vehicle (not shown).

The front lid 4 is formed in a cylindrical shape with a bottom,
It is attached by a bolt 9 while being fitted to the free end side of the journal portion 1a of the axle 1.

The oil draining sleeve 5 is fitted on the outer peripheral surface of the axle 1 in a region between the open end of the front lid 4 and the outer end surface of the first inner ring 11A.

The rear lid 6 is externally fitted on the neck side of the journal portion 1a of the axle 1 and has substantially the same shape as the oil draining sleeve 5.

The front lid 4, the oil draining sleeve 5, and the rear lid 6 form two inner races 11A, 1 provided for the rolling bearing 3.
By sandwiching 1B in the axial direction, the entire rolling bearing 3 is positioned in the axial direction. That is, the oil removing sleeve 5 and the first inner ring 11A are brought into axial contact with each other, and the rear lid 6 and the second inner ring 11B are brought into axial contact with each other. The oil removing sleeve 5 and the rear lid 6 correspond to the ring body described in the claims.

The sealing devices 7 and 8 are arranged on both sides in the axial direction of the rolling bearing 3 on the free end side of the journal portion 1a and on the wheel side, so that external muddy water, dust, etc. enter the inside of the rolling bearing 3. To prevent The sealing devices 7 and 8 are
It is the same, and as shown in FIG. 2, is provided with a case 20, a seal ring 21, and a metal ring 22. In addition,
FIG. 2 shows the details of the sealing device 8 on the rear lid 6 side, and the front lid 4
The details of the side sealing device 7 are not shown.

The case 20 is attached to one end of the outer ring 12 of the rolling bearing 3 in the axial direction, and surrounds the outer circumferences of the oil draining sleeve 5 and the rear lid 6. This case 20
Has a cylindrical shape with a step in the axial direction, one end side of which is attached to the inner peripheral end portion of the outer ring 12 and the other end side of which forms a maze without contact with the annular groove 17 of the rear lid 6. Is built in.

The seal ring 21 is formed by attaching three radial lips 26 to 28 to an annular core metal 25. The annular core metal 25 is fitted into the inner circumference of the case 20 by press fitting, and the three radial lips 26 to 28 are brought into contact with the outer peripheral surfaces of the oil draining sleeve 5 and the rear lid 6. Of the three radial lips 26 to 28, the main radial lip 26 whose upper half has a triangular cross section is tightened by a coil spring 29 mounted on the outer periphery thereof, so that the oil draining sleeve 5 and the rear lid 6 are secured. It can be pressed against the outer peripheral surface of the.

The metal ring 22 has a cylindrical portion 22a and an annular plate portion 22b extending inward in the radial direction from one end thereof. The cylindrical portion 22a is an annular core metal 25 of the seal ring 21.
It is fitted into the inner circumference by press fitting. The annular plate portion 22b is opposed to the outer peripheral surfaces of the oil draining sleeve 5 and the rear lid 6 with a minute gap therebetween. The metal ring 22 forms an annular space with the annular core metal 25 of the seal ring 21, and the annular space is filled with a lubricant (not shown) such as grease. The lubricant is used not only in the annular space but also in the radial lips 26 to 26 of the seal ring 21.
It is also held between 28.

In such a bearing unit 2, while the vehicle is traveling, a small amount of flexure is repeatedly generated in the axle 1 due to radial and axial loads, impacts, and vibrations, and the rear cover 6 and It is inevitable that fretting of metals occurs on the contact surface with the second inner ring 11B and metal abrasion powder is generated as in the conventional example.

Therefore, in this embodiment, even if fretting occurs on the contact surface and metal wear powder is generated, the metal wear powder is confined in the contact surface.

That is, in the rear lid 6, a step portion 9 having a small diameter is provided near the second inner ring 11B of the rolling bearing 3, and the packing 10 is fitted onto the step portion 9 with the diameter thereof elastically reduced. I am wearing it.

The packing 10 has a structure in which the elastic body 32 is covered with the spring ring 31 as a core material. For more information,
The cross section of the upper half of the packing 10 is formed in a substantially rectangular shape, and is covered with the elastic body 32 in a state where the spring ring 31 is arranged so as to be biased toward one end in the axial direction on the inner diameter side. Further, in the elastic body 32, recesses 33 and 34 which are continuous in the circumferential direction are respectively provided on the outer peripheral side and on the axial center side of the spring ring 31, and the elastic body 3
In FIG. 2, a recess 35 that is continuous in the circumferential direction is also provided in the radial center of the end surface where the spring ring 31 does not exist. The recesses 33 to 35 form three protrusions 32 a to 32 c on the elastic body 32.

The packing 10 is manufactured by vulcanizing and adhering the elastic body 32 of a required material to the spring ring 31. At that time, as shown in FIG. 4, three molds 40 to 42 are used. The first mold 40
Is a combination of two metal blocks 40A and 40B. The three molds 40 to 42 are packing 1
A cavity space 43 for defining the outer shape of the elastic body 32 of 0 is formed, but in the first and second molds 40 and 41,
The convex portion 40 for forming the depressions 33 to 35 of the elastic body 32
a, 40b, 41a are provided. Of these, the first
The convex portions 40a and 40b provided on the mold 40 serve to immobilize the spring ring 31 to be inserted into the cavity space 43, so that the elastic body 3
The spring ring 31 can be accurately and surely arranged in the two masses.

In the packing 10 having such a shape and configuration, as shown in FIGS. 2 and 3, when the packing 10 is mounted on the step portion 9, the spring ring 31 is arranged near the inner corner of the step portion 9, and Of the three projecting pieces 32a to 32c provided on the elastic body 32, the first projecting piece 32a extends obliquely inward in the radial direction and is brought into pressure contact with the outer end surface of the second inner ring 11B. The projecting piece 32c extends obliquely outward in the radial direction and is pressed against the outer end surface of the second inner ring 11B and the cylindrical surface 9b of the step portion 9, and further, the second projecting piece 32b.
Is pressed against the step wall surface 9a of the stepped portion 9. The contact surfaces between the rear lid 6 and the second inner ring 11B are reliably sealed by these three protrusions 32a to 32c. The broken line in FIG. 3 indicates the protruding piece 32 in the free state in which the packing 10 is not attached to the step portion 9.
a to 32c are shown.

By the way, with the provision of the step portion 9 and the packing 10 as described above, the positional relationship between the seal ring 21 and the metal ring 22 of the sealing device 8 is as follows.
That is, the three radial lips 26 to 28 provided on the seal ring 21 have the step portion 9 on the outer peripheral surface of the rear lid 6.
Is in contact with a region axially outward.
The annular plate portion 22b of the metal ring 22 is opposed to the area between the main radial lip 26 and the packing 10 on the outer peripheral surface of the rear lid 6 with a minute gap.

In the bearing unit 2 described above, the rear lid 6
Even if fretting of metal materials occurs on the contact surface between the second inner ring 11B and the second inner ring 11B, and the metal wear powder is generated, the outer diameter side of the contact surface is covered with the packing 10. Abrasion powder can be contained in the contact surface. Therefore, since it is possible to prevent the metal wear powder from entering the rolling bearing 3 and the sealing device 8, it is possible to extend the life of the metal wear powder as compared with the conventional example and reduce the running cost of the bearing unit 2. I can contribute.

Moreover, the packing 10 is formed by covering the elastic body 32 with the spring ring 31 as the core material, and the spring ring 31 is arranged near the inner corner of the stepped portion 9 in an elastically reduced diameter state. Therefore, the packing 10 can be mounted in a state where it is firmly tightened to the step portion 9,
It is possible to prevent the packing 10 from coming off from the step portion 9. Since the packing 10 is attached by the tightening force of the spring ring 31, it can be easily removed.

The packing 10 has a simple outer shape and can be mass-produced by vulcanizing and adhering the elastic body 32 to the spring ring 31, so that it can be manufactured at low cost.

The present invention is not limited to the above embodiment, and various applications and modifications are possible.

(1) In the above embodiment, the outer diameter side of the contact surface between the oil removing sleeve 5 and the first inner ring 11A may be closed by using the packing 10 similar to that described above. In this case, the oil removing sleeve 5 may be provided with the step portion 9 provided on the rear lid 6 described in the above embodiment, and the packing 10 may be attached to the step portion 9. As the packing 10 in this case, the packing 10 on the rear lid 6 side is used in the opposite direction.

(2) In the above embodiment, the rolling bearing may be of various types other than the double row outward tapered roller bearing.

(3) The present invention is applicable to not only the bearing unit 2 used to support the axles of railroad vehicles but also those used to support shafts such as rolling rolls and those used to support other shafts. Can be applied.

[0042]

According to the present invention, even if fretting occurs between metals on the contact surface between the ring body and the inner ring of the rolling bearing, and metal wear powder is generated, the metal wear powder is used for the aforesaid contact with the packing. Radiation outward from the contact surface can be prevented. Therefore, the life of the rolling bearing and the sealing device can be extended as compared with the conventional example, and the running cost of the bearing unit can be reduced.

Further, the packing has a structure in which a spring ring is used as a core material and is covered with an elastic body, and can be firmly attached to the step portion by the elastic tightening force of the spring ring. This is advantageous in that it facilitates removal and facilitates removal. Further, since the packing has such a structure, it can be manufactured at low cost by a manufacturing method such as vulcanization adhesion of an elastic body to a spring ring, which is advantageous in suppressing wasteful cost increase.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example in which a bearing unit according to an embodiment of the present invention is used in a railway vehicle.

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

FIG. 3 is an enlarged view of the packing in FIG.

FIG. 4 is a view showing a mold for manufacturing the packing shown in FIG.

[Explanation of symbols]

1 axle 1a Journal section 3 Rolling bearing 4 front lid 5 Oil draining sleeve 6 Rear lid 7,8 Sealing device 10 packing 11 Inner ring of rolling bearing

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16J 15/12 F16J 15/12 GF term (reference) 3J016 AA04 BB02 CA07 3J040 AA18 BA01 EA03 EA15 EA44 HA21 3J101 AA16 AA25 AA32 AA43 AA54 AA62 FA31 FA44 FA48 GA02

Claims (3)

[Claims] 1. A rolling bearing externally fitted to a shaft body and having at least an inner ring, and externally fitted to the outer circumference of the shaft body so as to come into axial contact with one end surface of the inner ring of the rolling bearing. An annular body for axially positioning the rolling bearing by means of a ring, and a sealing device arranged on the outer circumference of the annular body to close one end of the rolling bearing in the axial direction, and in the annular body near the inner ring of the rolling bearing. A stepped portion having a small diameter is provided, and the packing is externally fitted to the stepped portion while being elastically reduced in diameter, and the packing covers an elastic body with a spring ring as a core material. In the bearing unit, the spring ring is arranged near the inner corner of the step portion, and the elastic body is pressed against the end face of the inner ring. 2. The bearing unit according to claim 1, wherein the rolling bearing has two inner rings fitted to the shaft body axially adjacent to each other and each having one row of raceways, and each raceway surface of the two inner rings. A single outer ring having two rows of raceway surfaces that individually face each other in the radial direction, and a single outer ring that is respectively interposed between the two rows of raceways of the outer ring and the one row of raceways of each of the inner rings. A plurality of rolling elements, wherein the sealing device is attached to one axial end of the outer ring of the rolling bearing and surrounds the outer circumference of the ring body, and is fixed to the inner circumference of the case. A seal ring formed by applying a radial lip on the outer peripheral surface of the annular body, which is in contact with an area axially outward of the step portion, on the annular cored bar,
A bearing which is attached to the annular core of the seal ring and includes a metal ring which is opposed to a region between the radial lip and the packing on the outer peripheral surface of the ring body with a minute gap therebetween. unit. 3. The bearing unit according to claim 1 or 2, wherein an upper half of the packing has a substantially rectangular cross section, and the packing has a spring ring which is arranged on the inner diameter side at one end in the axial direction. A bearing unit, which is covered with an elastic body in a closed state, and in which a recess is provided in the elastic body on the other end side and the outer diameter side in the axial direction of the spring ring.