WO2010094361A1

WO2010094361A1 - Seal for a rolling bearing

Info

Publication number: WO2010094361A1
Application number: PCT/EP2009/066972
Authority: WO
Inventors: Bernard Nicola
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2009-02-19
Filing date: 2009-12-11
Publication date: 2010-08-26
Also published as: EP2399040A1; DE102009009633A1

Abstract

The invention relates to a seal (1) for a rolling bearing (2), comprising an outer bearing ring (5) or a housing, an inner bearing ring (9), cage-guided rolling elements (8), and an elastic sealing ring (3) having a reinforcement (10) circumferential to the outer bearing ring (5) or the housing and located by form fit in a receptacle or a ring groove (4) of the outer bearing ring (5), wherein the sealing ring (3) has a first sealing lip (14, 26) engaging with clearance in an undercut (16) of the inner bearing ring (9) adjacent to the rolling elements (8) and a second sealing lip (15) axially offset and aligned away from the rolling elements (8). A flexurally rigid sealing disc (19) having at least one inner, axially bent rim (20) is pressed against a cylindrical surface (18) of the inner bearing ring (9) for said seal (1), wherein the second sealing lip (15) protruding axially in the direction of the sealing disc (19) interacts with an inner surface (30) of the inner, axially bent rim (20) of the sealing disc (19), and a labyrinth gap (23) is formed between an outer, axially bent or cranked leg (21, 29) of the sealing disc and the seal (1).

Description

Name of the invention

Sealing for a rolling bearing

description

Field of the invention

The present invention relates to a seal for a rolling bearing, comprising an outer bearing ring or a housing, an inner bearing ring, cage-guided rolling elements and with the outer bearing ring or the housing encircling, elastic, a reinforcement having sealing ring, the form-fitting in a receptacle or an annular groove of the outer bearing ring is fixed in position, wherein the sealing ring is provided with a game in an undercut of the inner bearing ring adjacent to the rolling elements engaging first sealing lip and an axially spaced, directed away from the rolling elements, the second sealing lip.

Background of the invention

Such a seal is described in DE 103 36 341 A1. With this seal, both sealing lips protrude into the undercut in the inner bearing ring. In order to ensure a secure seal against moisture ingress of the rolling bearing, a sealing lip must be axially supported on the outer wall of the undercut. In order to reduce the friction at high speeds, the mass of this sealing lip forms a center of mass, and the centrifugal force acting in the center of mass to cause a reduction in the contact pressure to the outer wall of the undercut.

This seal has proven itself in operation, but it is in need of improvement in terms of the derivation of penetrated water spray or Condensation and with regard to protection against the ingress of and / or protection against foreign bodies.

Object of the invention

Based on the above-discussed prior art, the present invention seeks to provide a seal for a rolling bearing, which provides improved protection against the ingress of moisture and foreign bodies in the bearing and an improved discharge of liquid or in the region of the seal Condensate guaranteed.

Summary of the invention

Starting from a seal for a rolling bearing of the type mentioned, comprising an outer bearing ring or a housing, an inner bearing ring, cage-guided rolling elements, and one with the outer bearing ring or housing encircling, elastic, a reinforcement having sealing ring, the form-fitting in a receptacle or an annular groove of the outer bearing ring is fixed in position, wherein the sealing ring is provided with a play in an undercut of the inner bearing ring, adjacent to the rolling elements engaging first sealing lip and an axially spaced, directed away from the rolling elements second sealing lip, the invention proposes that a rigid sealing disc with at least one inner, axially bent board is pressed onto a cylindrical surface of the inner bearing ring, the second, axially projecting in the direction of the sealing disc sealing lip with an inner surface of the inner, axially bent Bordes the Dichtsche ibe cooperates and a labyrinth gap is formed between an outer axially bent or bent leg of the sealing disc and the seal.

The rigid sealing disc, which consists of a corrosion-resistant material, such as stainless steel, or at least on the outside is coated corrosion-resistant, for example, galvanized and / or elastomeric is coated, provides a mechanical protection for the existing mainly of a soft-elastic material sealing ring.

Furthermore, the installation of this seal is simplified, since first the sealing ring can be inserted into the rolling bearing and only then the sealing disc is pressed onto the inner bearing ring, wherein damage to the second sealing lip both during assembly of the sealing ring and when pressing the sealing washer avoided is, since this second sealing lip protrudes substantially horizontally and axially in the direction of the sealing disc and cooperates with the inner surface of the inner, axially bent Bordes the sealing disc.

The labyrinth gap formed between the sealing disc and the sealing ring largely prevents the penetration of moisture and particles, but it allows the outflow of moisture or condensate ingress of the rolling bearing, as well as the ejection of moisture and particles penetrated at rotating bearing, since the Rotate sealing ring with the outer bearing ring.

The first sealing lip is directed according to an advantageous development of the invention approximately radially inwardly into the undercut and rigid formed so that it at no time, neither at standstill of the bearing or at high speeds, with the wall surfaces of the undercut comes into contact and there none Frictional heat can arise.

Preferably, the second sealing lip protrudes axially approximately horizontally in the direction of the sealing disc and has a flexible edge, wherein it has a sealing edge which at standstill or low rotational speeds of the roller bearing on the cylindrical inner surface of the inner, axially bent towards the Wälz- body Bordes the sealing disc abradingly abuts and is lifted from the inner surface by the centrifugal force at higher speeds. This ensures that at standstill of the bearing no moisture can penetrate into the interior of the bearing, but that during the Rotation of the bearing no or only a slight friction between the sealing edge and the sealing disc occurs and thus no frictional heat and no wear can occur.

If the rolling bearing rotates and the sealing ring rotates with it, moisture and particles are thrown radially outward by the centrifugal force and leave the clearance between the sealing ring and the sealing disc via the previously mentioned labyrinth gap. This centrifugal force also prevents moisture and particles from entering the bearing interior from this clearance.

According to a first embodiment, the labyrinth gap, starting from the free space between the sealing disc and the sealing ring, initially extends approximately axially inwardly between an axial projection on the sealing ring and an axially bent leg on the sealing disc, then approximately radially in the direction of the annular groove and finally approximately axially outwardly between the outer race and the axially bent leg. This arrangement ensures safe protection of the sealing ring by the sealing disc and at the same time allows the flow and spewing of moisture and particles from the space between the sealing disc and the sealing ring.

According to a second embodiment, the labyrinth gap, starting from the free space between the sealing disc and the sealing ring initially approximately radially between the end of a bent leg on the sealing disc and the sealing ring and then approximately axially outwardly between the bent leg on the sealing disc and a extending axially outwardly projecting lip on the sealing ring. In this case, the lip of the sealing ring protrudes axially to approximately the outer surface of the sealing disc and forms the labyrinth gap with the bent limb on the sealing disc, without moisture and particles emerging or being ejected through this labyrinth gap with the outer bearing ring in Come in contact.

Similarly designed is another embodiment of the labyrinth gap, starting from the free space between the sealing disc and the sealing ring initially approximately radially between a bent leg on the sealing washer and the sealing ring and then extends approximately axially outwardly between the end of the cranked leg on the sealing washer and an axially outwardly projecting lip on the sealing ring. By the bend of the sealing disc, the axially outwardly projecting lip on the sealing ring can be made shorter, without thereby affecting the sealing effect in the labyrinth gap.

In all embodiments, it is advantageous that the labyrinth gap and the interaction of the second sealing lip with the axially bent rim of the sealing disc are not influenced by any axial play in the roller bearing.

If no contact at all between the second sealing lip and the bent rim of the sealing disc is desired, according to a further embodiment, a second labyrinth gap, starting from the undercut between an axial projection on the first lip of the sealing ring and an axially projecting into the region of the undercut Projection of the board of the sealing washer initially approximately axially inwardly extending, then approximately radially formed between the end of the supernatant of the board and the sealing lip and finally extending axially outwardly between the board and the Dichtlippenfuß in the direction of the sealing edge on the second sealing lip, so that together with the first labyrinth gap, a safe labyrinth system for sealing the rolling bearing is created.

In order to safely collect accumulated moisture in the space between the sealing washer and the sealing ring and derive at standstill down from the rolling bearing or centrifugally shed at rotating bearings by the centrifugal force, may be formed in the transition from the second sealing lip to Dichtlippenfuß a groove, the in addition to the flexural softness of the second sealing lip contributes.

The sealing disc is preferably made of a corrosion-resistant material, such as a hard plastic or stainless steel. The sealing However, only at least on the outside can the pane be corrosion-resistant, for example galvanized or coated with an elastomer.

The seal according to the invention can be used for example for a rolling bearing, which is provided in a tensioning roller or a deflection roller of a traction mechanism drive.

For component optimization, it makes sense to assign the seal according to the invention directly to a running disk of the tensioning roller or the deflection roller. For this purpose, the sealing ring is rotationally rigidly connected to the supported on a traction means running disk, which also takes over the function of the outer rotating bearing ring of the bearing. Such an arrangement is described in DE 10 2006 025 580 A1, the content of which is here completely made the subject matter of the disclosure.

Short description of the drawing

The invention will be explained in more detail below with reference to the accompanying drawings in some embodiments. It shows

1 shows an axial partial sectional view of a rolling bearing with the seal according to the invention according to a first embodiment, Fig. 2 shows a second embodiment of the seal assembly on the rolling bearing, and

Fig. 3 shows a third variant of the seal assembly.

Detailed description of the drawing

In Fig. 1, the structure of a first embodiment of the seal 1 according to the invention for a rolling bearing 2 is shown. The seal 1 comprises a sealing ring 3 which, on an outer circumference, elastically fits into an annular groove 4 of an outer ring. ßeren, encircling Lagerhngs 5 is positionally fixed in position. The circumferential with the bearing ring 5 sealing ring 3 encloses a circular installation space 6 of the rolling bearing 2, in which in a rolling element cage 7 guided rolling elements 8 are inserted, which are guided in raceways of the outer bearing ring 5 and an inner bearing ring 9.

The sealing disc 3 made of an elastic sealing material is provided for stiffening with a reinforcement 10, which is designed like a disk. In the direction of the outer bearing ring 5, the reinforcement 10 forms a right angle bevelled board 11. In the direction of the inner bearing ring 9, the reinforcement 10 has an inwardly inclined leg 12. At the reinforcement 10 of the sealing material of the sealing disc 3 is molded, which surrounds the board 11 and the leg 12 partially.

At the free end of the radially inner leg 12, a formed from the sealing material Dichtlippenfuß 13 connects. The Dichtlippenfuß 13 forms the basis for two sealing lips 14 and 15, of which the first sealing lip 14 protrudes into a, introduced into the inner bearing ring 9 undercut 16 without touching it. This first sealing lip 14 is due to their geometry and mass and shape substantially dimensionally stable, so that they at most slightly deformed due to the centrifugal force in rotating rolling bearing 2, without coming into contact with the walls of the undercut 16.

The second sealing lip 15 extends approximately horizontally and axially in the direction of a sealing disc 19 and cooperates with its radially inwardly directed sealing edge 17 with a cylindrical inner surface 30 of an approximately right-angled Bordes 20 on the sealing disc 19 together.

The sealing lip 15 is flexible against the occurring centrifugal forces, since the transition to the Dichtlippenfuß 13 has a relatively small cross-section and in this area in addition a groove 32 which is directed towards the Dichtlippenfuß 13 is formed. Between one of the rolling elements 8 pioneering axial projection 22 on the sealing ring 3, an axially inwardly bent legs 21 on the sealing disc 19, the annular groove 4 and the axial outlet of the outer race 5, a labyrinth gap 23 is formed, which is narrow and angular enough that virtually no moisture and particles can get into the free space 24 between the sealing ring 3 and the sealing disk 19, but which is far enough to allow moisture or condensate to flow out when the rolling bearing 2 is stationary due to gravity and particles are thrown off, Moisture and condensate during rotation of the rolling bearing 2 to allow.

At standstill of the rolling bearing 2, the second sealing lip 15 rests with its sealing edge 17 against the cylindrical inner surface 30 of the rim 20 and seals the undercut 16 and the interior of the rolling bearing 2 safely. If the roller bearing 2 is rotated, the sealing ring 3 rotates with the outer bearing ring 5, so that the sealing edge 17 of the second sealing lip 15 lifts from the cylindrical inner surface 30 of the rim 20 due to the centrifugal force and no or only one in this operating state very low friction between the sealing ring 3 and the sealing washer 19 is given. Due to the arrangement of the first sealing lip 14 in the undercut 16, the substantially horizontal and axially extending second sealing lip 15 and the formation of the labyrinth gap 23, there are no or only extremely small effects of axial play in the rolling bearing 2 on the sealing effect.

Oil or grease, which passes from the rolling elements 8 in the direction of the sealing ring 3, is collected by the first sealing lip 14 and fed back to the rolling elements 8 due to the centrifugal force with rotating rolling bearing 2.

An additional seal with a lubricant reserve can be given by filling the undercut 16 with lubricating grease.

The embodiment of FIG. 2 is basically similar in structure and in the operation comparable to the embodiment of FIG. 1. Der 1 is that a second labyrinth gap 28 between an axial projection 27 on the first lip 26 of the sealing ring 3, a projection 31 on the board 20 of the sealing washer 19, which projects into the region of the undercut 16, and the second sealing lip 15 is provided, the sealing edge 17 in this case, the cylindrical inner surface 30 of the rim 20 also does not touch when the rolling bearing 2. Furthermore, the first labyrinth gap 23 is formed between one end of the radially outer limb 21 of the sealing disc 19 and an axial lip 25 on the sealing ring 3, so that the annular groove 4 of the outer bearing ring 5 serves exclusively for fixing the position of the sealing ring 3.

The embodiment of FIG. 3 agrees with respect to the formation and effect of the first and second sealing lip 14, 15 with the embodiment of FIG. 1, while the sealing disc 19 as shown in FIG. 3 has an axially inwardly cranked leg 29, which together with the axial lip 25 on the sealing ring 3, the labyrinth gap 23 limited.

In all embodiments, an improved mechanical protection of the sealing ring 3 is given by the sealing washer 19 and the outflow of moisture and condensate in the free space 24 between the sealing disc 19 and the sealing ring 3 moisture and condensate at standstill of the rolling bearing 2 and a radial centrifuging of particles, moisture and Ensures condensate in rotating rolling bearing 2 without particles, moisture and / or condensate can get into the interior of the rolling bearing 2.

The rolling bearing 2 with its seal 3, 19 is preferably used in a tensioning roller or a deflection roller of a clamping system, with which a traction means of a traction mechanism is biased, wherein the structure of the tensioning roller or pulley comprises a rolling bearing enclosing the running disk, which at the same time the function of the outer , circumferential bearing ring takes over. This use is described in DE 10 2006 025 580 A1, the content of which is completely made the subject of the disclosure. LIST OF REFERENCE NUMBERS

Sealing 32 groove

roller bearing

seal

ring groove

Outer bearing ring

installation space

Rolling Element

rolling elements

Inner bearing ring

reinforcement

shelf

leg

Dichtlippenfuß

First sealing lip

Second sealing lip

Freeway

sealing edge

Cylindrical surface

sealing washer

shelf

leg

Axial projection

labyrinth gap

free space

Axial lip

First lip

Axial projection

labyrinth gap

Bent thigh

Cylindrical inner surface

Got over

Claims

claims

A seal (1) for a roller bearing (2), comprising an outer bearing ring (5) or a housing, an inner bearing ring (9), cage-guided rolling elements (8) and a peripheral to the outer bearing ring (5) or the housing, elastic, a reinforcement (10) having sealing ring (3), the form-fitting in a receptacle or an annular groove (4) of the outer bearing ring (5) is fixed in position, wherein the sealing ring (3) with a game in an undercut (16) of the inner Bearing rings (9), adjacent to the rolling elements (8) engaging, first

Sealing lip (14, 26) and an axially spaced, by the rolling elements (8) directed away second sealing lip (15), characterized in that a rigid sealing disc (19) having at least one inner, axially bent board (20) on a cylindrical Surface (18) of the inner bearing ring (9) is pressed, the second, axially in the direction of the sealing disc (19) protruding sealing lip (15) with an inner surface (30) of the inner, axially bent Bordes (20) of the sealing washer (19) cooperates and a labyrinth gap (23) is formed between an outer, axially bent or bent leg (21, 29) of the sealing disc (19) and the seal (1).

2. Seal according to claim 1, characterized in that the first sealing lip (14, 26) is directed approximately radially inwardly into the undercut (16) and formed rigid.

3. Seal according to claim 1 or 2, characterized in that the second sealing lip (15) protrudes approximately horizontally in the direction of the sealing disc (19) and is designed to be bendable.

4. Seal according to claim 3, characterized in that the second sealing lip (15) has a sealing edge (17) at standstill or low speeds of the rolling bearing (2) on the cylindrical inner surface (30) of the inner, axially bent Bordes (20 the sealing Be (19) abrading and is lifted from the inner surface (30) by the centrifugal force at higher speeds.

5. Seal according to one of claims 1 to 4, characterized marked, that the labyrinth gap (23), starting from a free space (24) between the sealing disc (19) and the sealing ring (3) initially approximately axially inwardly between an axial Projection (22) on the sealing ring (3) and an axially bent leg (21) on the sealing disc (19), then approximately radially in the direction of the annular groove (4) and finally axially outward between the outer bearing ring (5) and the axially bent leg (21) extends.

6. Seal according to one of claims 1 to 4, characterized in that the labyrinth gap (23), starting from a free space (24) between the sealing disc (19) and the sealing ring (3) initially approximately radially between the end of a bent leg ( 21) on the sealing disc (19) and the sealing ring (3) and then approximately axially outwardly between the bent leg (21) and an axially outwardly projecting lip (25) on the sealing ring (3).

7. Seal according to one of claims 1 to 4, characterized in that the labyrinth gap (23), starting from a free space (24) between the sealing disc (19) and the sealing ring (3) initially approximately radially between a bent leg (29) on the sealing disc (19) and the sealing ring (3) and then approximately axially outwards between the end of the bent leg (29) on the sealing disc (19) and an axially outwardly projecting lip (25) on the sealing ring (3) runs.

8. Seal according to one of claims 1 to 7, characterized in that a second labyrinth gap (28), starting from the undercut (16) between an axial projection (27) of a first lip (26) of the sealing ring (3) and an axially in the area of the undercut (16) the supernatant (31) of the Bordes (20) of the sealing disc (19) first approximately axially inwardly extending, then approximately radially between the end of the projection (31) of the Bordes (20) of the sealing disc (19) and the sealing ring (3) and Finally, approximately axially outwardly between the board (20) and the Dichtlippenfuß (13) in the direction of the sealing edge (17) of a second sealing lip (15) extending is formed.

9. Seal according to one of claims 1 to 8, characterized in that in the transition from the second sealing lip (15) to the Dichtlippen- foot (13) has a groove (32) is formed.

10. Seal according to one of claims 1 to 9, characterized in that the sealing disc (19) consists of a corrosion-resistant material.

11. Seal according to one of claims 1 to 9, characterized in that the sealing disc (19) is coated corrosion-resistant at least on the outside.

12. Seal according to one of claims 1 to 11, characterized in that the rolling bearing (2) is inserted in a tensioning roller or a deflection roller of a clamping system, with which a traction means of a traction mechanism drive is biased.

13. Seal according to claim 12, characterized in that the structure of the tensioning roller or deflection roller comprises a roller bearing (2) enclosing the running disk, which simultaneously assumes the function of the outer circumferential bearing ring (5).