DE10259400A1 - Sealing arrangement e.g. for rolling bearing of front wheels of motor vehicle has ring-shaped gap that is sealed by sealing element and has space formed between sealing element and conducting element - Google Patents

Abstract

The sealing arrangement is provided for two concentrically arranged rotary parts (2,3) that form a ring-shaped gap (6), which is sealed by a ring-shaped sealing element (9). Space (22) is formed between the sealing element and a conducting element (17) in which e.g. links (21), ribs are provided that give the air in the space a rotating movement when in rotation and a vacuum and/or suction is generated. The vacuum and/or suction acts on the sealing element.

Description

The invention is directed to a Sealing arrangement for two concentrically arranged rotating parts, at least partially an annular Form gap in which possibly circumferential rolling elements can be arranged, and by at least one annular Element is sealed. In such turned parts may be in particular around the inner and outer ring of a rolling bearing act, for example, for the storage of the driven front wheels of Motor vehicles.

When individually suspended wheels of a motor vehicle takes over a handlebar or - at non-driven wheels - a steering knuckle the leading one Alignment of a wheel. For storage of such vehicle wheels are usually two single, against each other employed camps to a double row Angular contact ball bearings combined with lifetime lubrication and sealing rings. While at least the outer seal with non-driven wheels often by means of a the stub loose embracing, at the wheel hub established cap is such a procedure not with driven wheels possible. Because there passes through a wave, on the one hand with the wheel and on the other hand is coupled to a constant velocity joint, the respective handlebar and learns there their storage. This bearing must be sealed at both ends become. The elastic sealing rings used in this case are often with metallic reinforcements stiffened, which ensures a stable position of the sealing rings and also for a high contact pressure of their sealing lips relative to the other bearing part Ensure that the grease contained over long periods of time Reliable retained can be. However, this brings the considerable disadvantage of greater friction with it, which unnecessarily increases the fuel consumption of the vehicle. Furthermore wear out the sealing lips due to the friction in an undesirable Measure, so that the lifetime lubrication is limited.

From these disadvantages of the state described The technique results in the problem initiating the invention, a generic seal assembly in such a way that the friction between the sealing lip the sealing ring and the rotary member opposite the sealing lip at least at Phases with increased Stress, that is generally defined at elevated relative speeds as possible can be reduced without affecting the sealing effect.

The solution to this problem succeeds through an outside of the annular Sealing element sealed gap region and arranged in such a way disc-shaped flow guide, that between the annular Seal element and the flow guide a gap is formed, in which approximately radially extending Webs, ribs, (stiff) flags od. Like. Are, during rotation the air contained in the space impart a rotational movement and due to the consequent centrifugal force a negative pressure and / or suction, which acts on the sealing element.

If the sealing lip is designed such that it experiences a force component directed radially away from the opposite rotary part due to negative pressure and / or suction, its contact pressure is reduced as a function of speed, with the result that the friction decreases under heavy load and thus on the one hand the required drive energy and on the other hand, the seal wear can be reduced. Thus, the sealing lip experiences a radial force component, it may have an adjacent to the space (annular) surface area along a section across the Abdichtring (in the longitudinal direction of the rotation axis of the rotating parts) at least in the installed state of the Abdichtrings an inclined course (so that a pressure force vector directed at right angles to this surface area is not directed parallel to the axis of rotation, but always also has a radial force component). On the other hand, the elasticity constant of the actual Abdichtrings and the cross section of the sealing lip should be set so that the maximum occurring at the maximum speed vacuum or suction force - possibly in conjunction with centrifugal forces acting on these - is not able to seal the lip of the completely remove the opposite rotating part, but only to relieve. Thereby, the sealing function is not completely interrupted, and grease contained in the sealed area can not leak out. Also, the access of external contaminant particles is reduced in many applications at high speeds, especially in the storage of the wheels of motor vehicles, since there occur only in fast moving car increased relative speeds, ie, for example, when driving on the highway, etc. In these cases In the context of the invention, the terms negative pressure and suction should be used to describe different physical effects: With negative pressure is a (static) negative pressure that is, when at constant speed and after pressure equalizing flows, the air (diluted due to the centrifugal force) does not move (in the radial and axial directions). On the other hand, a suction is caused by a (in the radial and / or axial direction) flowing air. Both effects can exert comparable effects on the sealing lip and depending on the embodiment either or together with each other be realized.

It has proven to be favorable that the sealing element in a surface area near the lip, but outside same, is curved, that its curvature around the axis of rotation of the rotating parts is stronger than any existing (convex or concave) curvature in the axial direction. This preserves the sealing lip in a section across the annular sealing element a relatively flat course, so that the negative pressure or suction forces on this flat vectorially to a resultant force with a pronounced Add up the radial force component. For optimal power development this area should either be directly adjacent to the sealing lip or you are diametrically opposed. For the same reason, the inclination angle of such should be cross-sectional flat surface area across from the axis of rotation of the mutually concentric rotary parts as possible be low, for example not more than 45 °, preferably not more than 30 °, in particular not more than 20 °; In this case, the radial component is the vacuum or suction force greater than its axial force component.

If the distance between one of the actual sealing lip diametrically opposite line of the outer surface of the Sealing element and the disc-shaped flow guide relatively small is, preferably smaller than the distance between this line and the sealing lip, so there are favorable flow conditions, which optionally with a flow of air to maximize the accompanying suction in the area of the sealing lip. optimal Results can be achieved when in the area of the sealing lip a flow constriction is realized, which is a local increase in flow velocity brings with it. It follows - similar to at the wing of an airplane - a the neighboring surfaces into the flow into raging Suction.

The approximately radial webs, Ribs, (stiff) flags od. Like. Each can be a rectangular footprint or an approximately trapezoidal base, whose Extension perpendicular to the disc-shaped element of their radial inside edge decreases towards its radially outer edge. This inventive concept can be to further develop that the largest axial extent of the approximately radially extending webs, ribs, (stiff) flags od. Like. is larger as half the mean distance between the sealing element and the disc-shaped flow-guiding element, preferably greater than 2/3 of this distance. The further the bridges at least in the area of their radially inward edge to the sealing ring, so to speak less pronounced from the negative pressure or suction in this important area mitigating vertebrae. In the radially further outside lying area, the formation of vertebrae is more tolerable, so that here also a greater distance the webs, ribs od. Like. To accept the sealing ring.

By the approximately radially extending Webs, ribs, (stiff) flags od. Like. At the disc-shaped flow guide fixed or molded, they experience one even for high speeds adequate mechanical stabilization. Optionally, but also in addition, the Webs, ribs od. Like. Also on a disc-shaped, preferably metallic Reinforcing element of the Abdichtrings be formed. This conditionally however, that this is not as usual from the inside of the sealed Accessible from the area is, but from the outside.

Preferably, the disc-shaped flow guide is made of a rigid material, in particular metal. By a selection of suitable materials can achieve high mechanical stability become. To a corrosion resistance can be made, for example, be made of aluminum, whereby By the way weight is saved. If, as stated above, the webs, etc. on the disc-shaped flow guide are formed, so this component can, for example. Made by die casting or by deep drawing.

The disk-shaped flow guide should on fixed at the normal movement (faster) rotating part his. Which rotary part is this is after the individual application case to decide. For vehicle wheels, for example. rotates the part connected to the wheel faster than one leading Handlebar or a non-driven axle stub.

For attachment of the disc-shaped flow guide recommends the invention, this by means of a press fit on a about (hollow) cylindrical portion of the respective rotary part to fix. Learns through it it simultaneously centering and aligning the appearance an imbalance largely excludes. Besides, it can be that way for fixing simply put on or in the relevant rotary part become.

The invention further provides that the disc-shaped flow guide at its attachment serving peripheral edge of a bent or flanged Edge and / or a tubular Approach over or in the selected for fixing, pushed (hollow) cylindrical portion of the respective rotary member is. This results in a widened contact surface between the rotating part and the disc-shaped flow guide, which results in an optimal alignment of the latter.

It is within the scope of the invention that the bent edge or the tubular extension extends at the side facing the gap of the disc-shaped flow guide. Since the optionally integrally formed on the flow guide webs are located on this page, can As a result, the entire, axially parallel extent of the disk-shaped flow guide be minimized.

The invention can be further developed in this way that the approximately radially extending webs, ribs, (stiff) Flags od. Like. Up to the bent edge or to the tubular approach extend. There you can they support one another and thus contributing to and further stabilizing additionally the formation of vertebrae in this area.

The disk-shaped flow guide undergoes a further, stabilizing stiffening in that the approximately radial running webs, ribs, (stiff) flags od. Like. With the bent edge or the tubular one Approach are connected.

The axial extent of a bent edge or a tubular one Approach can be the same or greater as the corresponding extent of the adjacent area of approximately radially extending webs, ribs, (stiff) flags od. Like. This results in a maximum hold of the disk-shaped flow guide.

An advantageous development of Invention is one or more in the disc-shaped flow guide Provide recesses for air passage, preferably each in the area between two adjacent ribs, webs od. Like. In that case - especially in cooperation with a gap between the unfixed peripheral edge the disc-shaped flow guide and that of this gegenüberlie ing Turned part - as a result the centrifugal acceleration of the rotating in the space Air a radial flow train, which is an additional To exercise on the sealing lip can.

When the recess (s) close the radially inner edge or the fastening edge or the bent edge or tubular extension (s), so the entire space between the sealing ring and disk-shaped flow guide and thus also the area near the sealing lip of a radial flow includes.

After all, it is teaching the invention that several recesses for the passage of air equidistantly over the Circumference distributed. This will cause strong turbulence due to different flow conditions in different "chambers" of the gap avoided.

Other features, details, benefits and Effects on the basis of the invention will become apparent from the following Description of a preferred embodiment of the invention as well based on the description. Hereby shows:

1 a cross section through both rings of a rolling bearing in the region of a rolling body and by a sealing device arranged outside the running surface; such as

2 an end view of an inventive part of the sealing device 1 ,

The sealing principle of the invention is based on a rolling bearing in the drawing 1 explained. This may be, for example, a bearing for the driven front wheel of a motor vehicle. In this case, there are between an optionally split inner ring 2 and the outer ring 3 two rows of spherical rolling elements 4 whose careers 5 are inclined, so that the radial guidance is accompanied by a position stabilization of the wheel plane. One in the gap 6 between the two bearing rings 2 . 3 arranged cage 7 encloses the rolling elements 4 and ensures even spacing of the same.

The area of the rolling elements 4 and careers 5 is (preferably at both ends 8th of the camp 1 ) through a sealing ring 9 Protected from penetrating particles. For fixing the sealing ring 9 is in the area of the frontal edge of the inside 10 a circumferential, groove-shaped depression 11 provided, in which the sealing ring 9 with a circumferential, elastic ring extension 12 snapped and thereby fixed. The sealing ring 9 extends across the annular gap 6 up to the inner ring 2 and lies with a sealing lip 13 on its inner edge on the inner ring 2 sealingly. This is the room 6 inside the sealing ring 9 completely finished and may preferably be completely filled with grease. So that the lubricated grease, which is pressed outwards during rotation, does not lead to a deformation of the sealing ring 9 This is in its middle area between its inner sealing lip 13 and its outer ring extension 12 through an annular metal sheet 14 reinforced. For fixing on the metal reinforcement 14 can its inner and or outer edge of the elastic sealing ring 9 be formed surrounding; In this case, the metal reinforcement can be completely or only wrapped on one end face. To their stiffening can the metal reinforcement 14 at its inner and / or outer periphery preferably inwardly (in the direction of the relevant career 5 towards) flanged edges 15 respectively.

The area of the sealing lip 13 can also be designed resilient by between the respective edge of the reinforcement 14 and the sealing lip a bead-shaped depression 16 is formed, the depth of which is preferably greater than the thickness of the Armierungsblechs 14 so that the sealing lip 13 not directly on the edge of the reinforcement 14 supports and instead experiences a radial degree of freedom of movement. Preferably, the bead-shaped depression is located 16 on the outside of the sealing ring 9 ,

On the outside of the sealing ring 9 there is a disk-shaped flow guide 17 which taken by itself in 2 is reproduced. It has an annular shape with an approximately L-shaped cross section (see. 1 ), whose two legs 18 . 19 preferably at a right angle to each other. A thigh 18 of the L-shaped cross section is approximately parallel to the base plane of the rolling bearing 1 ; the relevant part of the flow guide 17 has the shape of a flat disc or at best a slightly conical shape. The other thigh 19 of the L-shaped cross section forms an approximately cylindrical projection on the inner circumference of the first, approximately disc-shaped part 18 , This approach 19 could for example be formed by bending a radially inner edge region of a disc-shaped sheet metal blank.

The at the radially inner side of the approach 19 measured diameter is minimally smaller in the manner of a press fit than the outer diameter of the relevant cylindrical portion of the inner ring 2 , so that the disc-shaped flow guide 17 can be fixed immovably by pushing on the inner ring. The flow-guiding element is preferred 17 doing so postponed that his cylindrical neck 19 inside towards the sealing lip 13 is aligned. A (minimum) distance between the outermost edge of this cylindrical approach 19 and the sealing lip 13 the latter allows a frictionless radial movement.

How out 2 that have a view on the inside 20 the flow guide 17 shows, it can be seen further, located on this inside 17 , which in the installed state the sealing ring 9 adjacent, several, in the present case six equidistantly distributed over the circumference arranged, flat webs 21 , The base of all these webs is in each case with respect to the axis of rotation of the bearing 1 radial-axial planes. The basic shape of these webs is preferably rectangular or trapezoidal, but could also be designed differently. In the illustrated example, the radial extent of the flat or flag-like webs corresponds 21 the corresponding extent of the disc-shaped part 18 the flow guide 17 ; their axial extension is slightly smaller than the relevant extent of the cylindrical extension 19 and also decreases steadily and uniformly from the radially inner edge toward the outer edge. The bridges 21 are preferably both with the disc-shaped part 18 the flow guide 17 as well as with the cylindrical approach 19 connected or manufactured technically (eg. By a common injection molding process step) and therefore contribute significantly to the stiffening of the flow 17 at.

In the illustrated embodiment of a rolling bearing 1 for a driven front wheel of a motor vehicle is the inner ring 2 pushed on a wheel supporting the drive shaft and therefore rotates with the number of revolutions of the wheel in question, while the outer ring 3 for example, is received in a socket of a handlebar and therefore stands still. For this reason, the flow guide rotates 17 when starting the vehicle in question with a speed proportional to the driving speed. As the number of revolutions increases, so does the wing-like or flag-like webs 21 the air in the room 22 between the sealing ring 9 and flow guide also set in rotation and undergoes an outwardly directed centrifugal acceleration, resulting in a pressure reduction in the radially inner region of the gap 22 where the sealing lip 13 located, leads. The air can for this purpose through a gap 23 between the outer periphery of the flow guide 17 and the outer ring 3 escape 25 ,

As a result of such (static) negative pressure in the gap 22 decreases on the radially inner side 24 and flank of the bead 16 exerted pressure force, whereby the contact pressure of the sealing lip 13 is reduced. As a result, their wear and also the energy required to overcome the friction is reduced. The parameters of the overall arrangement, in particular the elasticity of the sealing lip 13 and the bead 16 adjacent area, are preferably adjusted so that even at the maximum speed of the vehicle, the sealing lip 13 does not lift off the inner ring so that the sealing effect remains intact.

If, on the other hand, even greater relief of the sealing lip 13 may be desired in the disc-shaped part 18 the flow guide 17 near the cylindrical neck 19 one or more recesses 26 to the air passage 27 be provided. Ideally, per "chamber", ie between each two adjacent bars 21 , one recess each 26 to be available. In this case, as a result of a rotation of the flow guide 17 and its webs 21 generated negative pressure within the gap 22 Air from outside the flow guide 17 through its recesses 26 in the gap 22 sucked, there accelerated radially outward and through the gap 24 delivered to the outside. Thus, there is a continuous flow of air through the gap 22 as they are in 1 is drawn.

This air flow has the physical property of adjacent surface areas, ie in particular on the radially inner side 24 of the bead-shaped depression 16 or another top of the sealing lip 13 to exert a pull. This suction leads as well as the (static) negative pressure to a relief of the sealing lip 13 ,

The suction effect of the (radial) air flow within the gap 22 is greatest at narrowing areas of the flow, since there the flow velocity is maximum. For this Reason, the suction effect on the sealing lip can be further enhanced if necessary, by a flow restriction is provided near the sealing lip. This could be achieved, for example, by the fact that on the inside 20 of the disc-shaped part 18 the flow guide 17 radially outside the cylindrical extension 19 and also outside the Luftdurchtrittsausnehmungen 26 an annular rib is provided (in the 1 for reasons of space not shown), which - preferably obliquely radially inward - to above the sealing lip 13 or even into the bead-shaped depression 16 protrudes and forces the flow of air, just above the sealing lip 13 to strip along. The then increased flow rate maximizes the radially outward suction on the sealing lip 13 ,

Claims (18)

Sealing arrangement for two concentrically arranged turned parts ( 2 . 3 ), which at least partially an annular gap or gap ( 6 ), in which optionally revolving rolling elements ( 4 ), and by at least one annular element ( 9 ), characterized by an outside of the annular sealing element ( 9 ) sealed gap area ( 6 ) and thus arranged, disc-shaped flow guide ( 17 ) that between the annular sealing element ( 9 ) and the disc-shaped flow guide ( 17 ) a gap ( 22 ) is formed, in which approximately radially extending webs ( 21 ), Ribs, (stiff) lugs od. Like., Which in rotation in the space ( 22 ) and cause, due to the consequent centrifugal force, a negative pressure and / or suction, which is transmitted to the sealing element (FIG. 9 ) acts. Sealing arrangement according to claim 1, characterized in that the sealing element ( 9 ) in a surface area ( 24 ) near its lip ( 13 ), but outside of it, is curved in such a way that its curvature about the axis of rotation of the rotating parts ( 2 . 3 ) is stronger than any existing (convex or concave) curvature in the axial direction. Sealing arrangement according to claim 2, characterized in that the angle of inclination of such, in the axial direction relatively small curved surface area ( 24 ) relative to the axis of rotation of the mutually concentric rotating parts ( 2 . 3 ) is less than 45, preferably less than 30 °, in particular less than 20 °. Sealing arrangement according to one of claims 1 to 3, characterized in that the distance between one of the actual sealing lip ( 13 ) diametrically opposite line of the outer surface ( 24 ) of the sealing element ( 9 ), in particular in the region of one of the sealing lip ( 13 ) subsequent, bead-shaped depression ( 16 ), and a part of the flow guide ( 17 ) is smaller than the distance of this line to the sealing lip ( 13 ) and / or the opposite, radially inner rotary part ( 2 . 3 ). Sealing arrangement according to one of the preceding claims, characterized in that the approximately radially extending webs ( 21 ), Ribs, (stiff) lugs od. Like. Each having a rectangular base or an approximately trapezoidal base surface whose extension is perpendicular to the disc-shaped flow guide ( 17 ) decreases from its radially inner edge to its radially outer edge. Sealing arrangement according to one of the preceding claims, characterized in that the largest, axial extension of the approximately radially extending webs ( 21 ), Ribs, (stiff) lugs od. Like. Is greater than half the average distance between the sealing element ( 9 ) on the one hand and the disk-shaped flow guide ( 17 ) On the other hand, preferably greater than 2/3 of this distance. Sealing arrangement according to one of the preceding claims, characterized in that the approximately radially extending webs ( 21 ), Ribs (stiff) lugs od. Like. At the disk-shaped flow guide ( 17 ) are fixed or molded. Sealing arrangement according to one of the preceding claims, characterized in that the disk-shaped flow guide ( 17 ) is formed of a rigid material, in particular metal. Sealing arrangement according to one of the preceding claims, characterized in that the disk-shaped flow guide ( 17 ) on the rotating part (faster) during normal motion ( 2 . 3 ). Sealing arrangement according to one of the preceding claims, characterized in that the disk-shaped flow guide ( 17 ) by means of a press fit on an approximately (hollow) cylindrical portion of the respective rotary part ( 2 . 3 ). Sealing arrangement according to claim 10, characterized in that the disk-shaped flow guide ( 17 ) at its attachment peripheral edge a bent or flanged edge ( 19 ) and / or a rohrförmi Approach approach, the above or in the selected for fixing, (hollow) cylindrical portion of the respective rotary part ( 2 . 3 ) is pushed. Sealing arrangement according to claim 11, characterized in that the bent edge ( 19 ) or the tubular approach at the the space ( 22 ) facing side ( 20 ) of the disc-shaped flow guide ( 17 ). Sealing arrangement according to claim 12, characterized in that the approximately radially extending webs ( 21 ), Ribs, (stiff) flags od. Like. Up to the bent edge ( 19 ) or tubular extension. Sealing arrangement according to claim 13, characterized in that the approximately radially extending webs ( 21 ), Ribs, (stiff) flags od. Like. With the bent edge ( 19 ) or rigidly connected to the tubular extension. Sealing arrangement according to one of claims 11 to 14, characterized in that the axial extent of the bent edge ( 19 ) or a tubular extension is equal to or greater than the corresponding extent of the adjacent region of the approximately radially extending webs ( 21 ), Ribs, (stiff) flags od. Like. Sealing arrangement according to one of the preceding claims, characterized in that mungsleitelement in the disc-shaped Strö ( 17 ) one or more recesses ( 26 ) to the air passage ( 27 ), preferably in each case in the region between two adjacent webs ( 21 ), Ribs or the like Sealing arrangement according to claim 16, characterized in that the recesses () 26 ) near the radially inner edge or the fastening edge of the flow guide ( 17 ) or of the bent edge ( 19 ) or tubular approach is (-en). Sealing arrangement according to claim 16 or 17, characterized in that a plurality of recesses ( 26 ) to the air passage ( 27 ) equidistant over the circumference of the flow guide ( 17 ) are arranged distributed.