JPH11218141A - Bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve dust-proof and water-proof performance and obtain a long service life. SOLUTION: An extended part 2g2 of an elastic body 2g is extended from a radial part 2f13 of a base part 2f1 to a bent part 2f12. Contact parts A, B are formed between the radial part 2f13 of the base part 2f1 and a stepped wall 2a12 of a seal fitting part 2a1 and between the bent part 2f12 of the base part 2f1 and a circumferential groove 2a11 of the seal fitting part 2a1 respectively through the extended part 2g2 of the elastic body 2g, and a fixed part of the base 2f1 and seal fitting part 2a1 is closed without a clearance in the contact parts A, B. Lips 2g11, 2g12, 2g13 of the elastic body 2g are elastically deformed by an interference with a seal sliding contact face 2b1 so as to come in face contact with the seal sliding contact face 2b1 with moderate contact pressure and contact area without mutual interferernce.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing unit in which a rolling bearing and a bearing housing are unitized, and more particularly to a bearing unit having a long life even in an environment where dust, water, and the like are scattered.

[0002]

2. Description of the Related Art A bearing unit of this type has a function of automatically aligning a spiral of a shaft caused by a machining error or a mounting error of a shaft. , Flange type, take-up type, plummer type, etc. In the case of using a pillow-type or flange-type open-ended bearing box, seals are used as bearings to prevent foreign substances from entering the bearings (ingress of dust, water, etc.) and prevent grease from leaking from inside the bearings. The bearing (rolling bearing equipped with a seal) is used, and the centering operation of the bearing is enabled by the spherical fitting between the spherical outer diameter surface of the outer ring and the spherical seat of the bearing box.

FIG. 4 shows a seal of a sealed type rolling bearing incorporated in this type of bearing unit (for example, Japanese Utility Model Laid-Open No. 53-9 / 1983).
No. 5938). The seal 10 is of a contact type, and has a base metal 10a having a base 10a1 fitted and fixed to a seal mounting portion 11a at the end of the outer race 11.
and three lips 10b1, 10b integrated with the cored bar 10a and slidingly contacting the seal sliding contact surface 12a of the inner race 12.
And an elastic body (rubber body) 10b having 2, 10b3.

The base 10a1 of the cored bar 10a is cut out at a plurality of positions in the circumferential direction by slits 10a5. This is because the elastic deformation capability of the base 10a1 is increased, and the fitting margin with the seal mounting portion 11a is increased. An intermediate portion between the base portion 10a1 and the inner diameter portion 10a4 of the cored bar 10a includes a cylindrical portion 10a2 and a radial portion 10a3 continuous from the cylindrical portion 10a2 to the inner diameter side.

[0005] The elastic body 10b is formed of a cylindrical portion 10 of a metal core 10a.
It is integrally molded by vulcanization or the like on the inner surface of an intermediate portion mainly composed of a2 and the radial portion 10a3. 3 of the elastic body 10b
Each of the lips 10b1, 10b2, and 10b3 is elastically deformed by interference with the seal sliding contact surface 12a of the inner ring 12, and their tips (inner diameter portions) closely contact the seal sliding contact surface 12a to seal the inside of the bearing. I do.

[0006]

The following problems can be pointed out with respect to the above-mentioned conventional seal structure. (1) Since the slit 10a5 is provided in the base 10a1 of the cored bar 10a, foreign substances such as dust and water can be removed from the slit 10a5.
It is inevitable to intrude into the fitting portion between the base 10a1 and the seal mounting portion 11a via a5. On the other hand, the base 10
The contact between a1 and the seal mounting portion 11a is a contact between metals, and it is difficult to obtain sufficient close contact. Therefore, foreign matter that has entered the fitting portion via the slit 10a5 easily enters the inside of the bearing through the gap between the contact portion between the base 10a1 and the seal mounting groove 11a. (2) The tip of each lip of the elastic body 10b is in contact with the seal sliding contact surface 12a in a state close to line contact, and it cannot be said that the closeness of the lip portion is sufficient. (3) If the interference with the seal sliding surface is increased in order to increase the closeness of the lip portion, the friction torque increases, causing an increase in bearing torque. The contact state becomes unstable. (4) For the above reasons, the conventional bearing unit is not sufficiently dustproof and waterproof, and it is difficult to achieve a long life.

[0007] The present invention is directed to a dust-proof type bearing unit of this type.
Its purpose is to increase the waterproof performance and achieve a longer life.

[0008]

In order to achieve the above object, the present invention provides a metal core having a base fixed to a seal mounting portion at an end of an outer ring of a rolling bearing, and a metal integrated with the metal core, An elastic body having a plurality of lips slidingly contacting the seal sliding surface of the inner ring, the elastic body extending to at least a part of the base of the core, and the seal between the base of the core and the seal mounting portion of the outer ring. A configuration in which a close contact portion is formed between the extension portions of the elastic body is provided therebetween.

The seal mounting portion of the outer ring includes various shapes such as those having a circumferential groove and a step wall, those having only a circumferential groove, those having only a step wall, and those having a flat shape. The means for fixing the base portion of the core bar includes various fixing means such as fixing by a fitting force, fixing by a caulking force, and fixing by a combination of a fitting force and a caulking force. The elastic body is rubber,
It is formed of an elastic material such as resin, and the number of lips is not particularly limited as long as it is plural, but it is preferable that the number of lips is three.

[0010] In order to further enhance the sealing performance, a plurality of lips of the elastic body may be brought into surface contact with the seal sliding contact surface of the inner race by their elastic deformation and without mutual interference.

[0011]

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

FIG. 1 illustrates a pillow type bearing unit. This bearing unit includes a bearing box 1 having a spherical seat 1a on the inner diameter, and a sealed rolling bearing 2 fitted to the spherical seat 1a of the bearing box 1 so as to be able to move in an aligned manner. A pair of mounting seats 1b are provided on both sides of the bottom of the bearing housing 1, and the mounting of the bearing unit is performed by fixing the mounting seat 1b of the bearing housing 1 to a mounting location with bolts.

The rolling bearing 2 is, for example, a deep groove ball bearing,
Spherical outer diameter surface 2a1 fitted to spherical seat 1a of bearing housing 1
Outer ring 2a having an inner ring, inner ring 2b, outer ring 2a and inner ring 2b
, A plurality of balls 2c interposed therebetween, a retainer 2d for holding the balls 2c at predetermined circumferential intervals, and a pair of seals 2e attached to both ends of the outer ring 2a. Inner ring 2
b is wider than the outer ring 2 a, and one side thereof protrudes from the side of the bearing housing 1. As shown in FIG. 1 (b), after the shaft 3 is inserted into the inner surface of the inner ring 2b, a set screw 4 is screwed into a screw hole on one side of the inner ring 2b, and tightened. This is performed by pressing the tip against the outer peripheral surface of the shaft 3. If the set screw 4 is a ball-in set screw (having a structure in which a ball is incorporated therein. When the set screw is tightened, the ball is pressed against the outer peripheral surface of the shaft), the shaft 3 can be easily mounted. The effect of preventing loosening is great.

FIG. 2 shows a seal 2 e mounted on the rolling bearing 2. The seal 2e includes a core 2f and a core 2
f and an elastic body 2g integrated with f.

The cored bar 2f is formed by press-forming a galvanized steel plate, for example, and includes a base 2f1, an intermediate portion 2f2 inclined from the base 2f1 to the inner diameter side, and an intermediate portion 2f.
2 and an inner diameter portion 2f3 that is continuous in a flange shape from the inner diameter side to the inner diameter side. The distal end portion 2f11 of the base 2f1 is bent outward in a folded manner, and is continuous with the radial portion 2f13 via a curved portion 2f12 having a curvature. The base 2f1 has a shape in which the cross section shown in the figure is continuous in the circumferential direction, and does not include the slit (10a5) as shown in FIG.

The elastic body 2g is formed by vulcanizing and molding a rubber material such as nitrile rubber on a cored bar 2f.
Is attached to the inner surface of the intermediate portion 2f2 and the inner diameter portion 2f3 of the cored bar 2f, and the extended portion 2g2 is continuously attached from the main portion 2g1 to the outer diameter side, and is attached to the inner surface of the base portion 2f1. In this embodiment, the extending portion 2g2 is a bent portion 2f12 of the base 2f1.
Extends to The inner diameter side portion of the main portion 2g1 is 3
The outer lip 2
g11, intermediate lip 2g12, inner lip 2g13
Make up one lip.

In this embodiment, the main dimensions of the three lips (2g11, 2g12, 2g13) shown in FIG. 1 are set as follows. First, the width W of each lip (W1, W1
2, W3) and the length L (L1, L2, L3) (W /
L) is set in the range of 0.15 ≦ (W / L) ≦ 0.25. As a result, the waist of each lip can be made appropriately flexible, the close contact with the seal sliding contact surface 2b1 of the inner ring 2b described later can be increased, and the friction torque of the sliding contact portion can be suppressed low. Next, the distance D (D1, D1,
D2) and length L (L1, L2, L3) (D / L)
Is set in the range of 0.35 ≦ (D / L) ≦ 0.55. Thus, interference between the lips can be prevented, and a stable sliding contact state can be maintained. Further, the width W1 of the outer lip 2g11 is slightly larger than the widths W2 and W3 of the other lips, and the length L of the outer lip 2g11 is L.
1 is the same size as or slightly smaller than the lengths L2 and L3 of the other lips. Thereby, the waist of the outer lip 2g11 is made slightly stronger than the other lips, the close contact force with the seal sliding contact surface 2b1 is increased, and the effect of preventing foreign matter from entering from the outside can be enhanced. The widths W2 and W3, the lengths L2 and L3, and the intervals D1 and D2 can be set to the same dimensions (W2 = W3, L2 = L3, D1 = D).
2).

FIG. 3 shows a state in which the seal 2e having the above structure is mounted on the end of the rolling bearing 2. The base 2f1 of the core 2f of the seal 2e is fixed to a seal mounting portion 2a1 formed at the inner diameter of the end of the outer ring 2a, and the three lips 2g11, 2g12, 2g13 of the elastic body 2g of the seal 2e.
Are in sliding contact with a seal sliding contact surface 2b1 formed at the end outer diameter of the inner ring 2b with a predetermined interference.

The seal mounting portion 2a1 of the outer race 2a is composed of a circumferential groove 2a11 and a radial step wall 2a12 which is continuous from the inner shoulder of the circumferential groove 2a11 to the inner diameter side.
The base 2f1 has a bent portion 2f12 having a circumferential groove 2a1.
1 and is fixed to the seal mounting portion 2a1 in a state where the radial portion 2f13 is in close contact with the step wall 2a12. In this embodiment, the extension 2g2 of the elastic body 2g is connected to the base 2f1.
Extends from the radial portion 2f13 to the bent portion 2f12, so that the base 2f1 is attached to the seal mounting portion 2a1.
, The elasticity between the radial portion 2f13 of the base 2f1 and the stepped wall 2a12 of the seal mounting portion 2a1, and between the bent portion 2f12 of the base 2f1 and the circumferential groove 2a11 of the seal mounting portion 2a1, respectively. Extension 2 of body 2g
Close parts A and B are formed via g2, and the fixed part between the base 2f1 and the seal mounting part 2a1 is closed at the close parts A and B without any gap. Therefore, it is difficult for foreign matter to enter the inside of the bearing from the fixed portion. The extension 2 of the elastic body 2g
g2 may be extended to the tip 2f11 of the base 2f1. Conversely, the extension 2g2 of the elastic body 2g is connected to the base 2f1.
Up to the radial portion 2f13, and only the close contact portion A may be formed. In addition, the fixing of the base 2f1 to the seal mounting portion 2a1 may be performed by a fitting force.
It is good to use caulking together. In this case, if the point caulking method is adopted, the fixed state is stabilized, and the co-rotation of the outer ring 2a and the seal 2e can be effectively prevented.

The seal sliding contact surface 2b1 of the inner ring 2b is finished smoothly by grinding or the like, and the lips 2g11, 2g12, 2g13 of the elastic body 2g are elastically deformed by the interference with the seal sliding contact surface 2b1, respectively. , And comes into close contact with the seal sliding contact surface 2b1. By the above-described dimension setting, the lips 2g11, 2g12, and 2g13 are in surface contact with the seal sliding contact surface 2b1 with an appropriate contact pressure and contact area without interfering with each other. Therefore, each lip 2g11,
The close contact of the 2g12 and 2g13 with the seal sliding contact surface 2b1 is good and stable, and a high sealing property is obtained. In addition, the friction torque of the sliding contact portion of each lip is low, and an increase in bearing torque is suppressed.

The present invention is not limited to the pillow type bearing unit illustrated in FIG. 1, but can be widely applied to a bearing unit using a sealed type rolling bearing such as a flange type or a take-up type.

[0022]

The present invention has the following effects.

(1) Since a close contact portion is formed between the base portion of the core of the seal and the seal mounting portion of the outer ring via the extension portion of the elastic body, the fixed portion between the base portion and the seal mounting portion is formed. It is difficult for foreign matter to enter the bearing.

(2) A plurality of lips of the elastic body of the seal
Due to their elastic deformation and without interfering with each other, the inner ring is in surface contact with the seal sliding contact surface, so that each lip has good and stable close contact with the seal sliding contact surface, and high sealing performance is obtained. .

(3) Due to the above effects, the dustproof and waterproof performance of this type of bearing unit and the rolling bearing for the bearing unit are improved, and the life is extended.

[Brief description of the drawings]

FIG. 1 is a front view (FIG. A) and a partial longitudinal sectional view (FIG. B) showing a bearing unit according to an embodiment.

FIG. 2 is a sectional view of a seal.

FIG. 3 is a partial cross-sectional view showing a state where a seal is mounted on a rolling bearing.

FIG. 4 is a cross-sectional view showing a state where a conventional seal is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing box 1a Spherical seat 2 Rolling bearing 2a Outer ring 2a1 Seal attachment part 2b Inner ring 2c Ball 2d Cage 2e Seal 2f Core 2f1 Base 2g Elastic body 2g2 Extension 2g11 Lip 2g12 Lip 2g13 Lip A Close contact part B Close contact part

Claims (9)

[Claims] 1. A bearing unit in which rolling bearings having seals attached to both ends of an outer ring having a spherical outer diameter surface are fitted to a spherical seat of an inner diameter of a bearing box so as to be capable of centering and moving. A core having a base fixed to the seal mounting portion at the end of the outer ring, and an elastic body integrated with the core and having a plurality of lips sliding on a seal sliding contact surface of the inner ring, The elastic body extends to at least a part of the base of the metal core, and a close contact portion is formed between the base of the metal core and the seal mounting portion of the outer ring via the extension of the elastic body. Features bearing unit. 2. The lip of the elastic body according to claim 1, wherein the plurality of lips make surface contact with the seal sliding contact surface of the inner race by their elastic deformation and without interfering with each other. Bearing unit. 3. The bearing unit according to claim 1, wherein the number of the lips is three. 4. An outer ring having a spherical outer diameter surface fitted into a spherical seat of a bearing housing, an inner ring wider than the outer ring, a plurality of rolling elements interposed between the outer ring and the inner ring, and a rolling element. In a rolling bearing for a bearing unit provided with a retainer for holding the outer ring at predetermined intervals and seals attached to both ends of the outer ring, the base is fixed to a seal mounting portion at the end of the outer ring. A core having a plurality of lips integrated with the core and having a plurality of lips slidably in contact with the seal sliding surface of the inner ring, wherein the elastic extends to at least a portion of a base of the core; A rolling bearing for a bearing unit, wherein a close contact portion is formed between a base portion of a cored bar and a seal mounting portion of the outer ring via an extending portion of the elastic body. 5. The lip of the elastic member according to claim 4, wherein the plurality of lips make surface contact with the seal sliding contact surface of the inner race by their elastic deformation and without interfering with each other. Rolling bearing for bearing unit. 6. The rolling bearing for a bearing unit according to claim 4, wherein the number of the lips is three. 7. A seal for a rolling bearing for a bearing unit, which is fitted to a spherical seat of a bearing box so as to be capable of centering and moving, wherein a core having a base fixed to a seal mounting portion at an end of an outer ring; An elastic body integrated with the core metal and having a plurality of lips sliding on a seal sliding contact surface of the inner ring, wherein the elastic body extends to at least a part of a base of the core metal, and A seal for a rolling bearing for a bearing unit, characterized in that when fixed to the seal mounting portion of the outer ring, a close contact portion is formed between the two via an extending portion of the elastic body. 8. A method according to claim 7, wherein the plurality of lips of the elastic body are in surface contact with the seal sliding contact surface of the inner race by their elastic deformation and without interfering with each other. Rolling bearing seals for bearing units. 9. The rolling bearing seal for a bearing unit according to claim 7, wherein the number of the lips is three.