DE102013210521B4 - Bearing with volume compensation element - Google Patents

Abstract

Bearing (100) having the following features: a first bearing ring (120) and a second bearing ring (130); at least one row (160) of rolling elements (170) arranged between the first bearing ring (120) and the second bearing ring (130); at least one bearing seal (260) sealing an interior space (250) of the bearing (100) between the first bearing ring (120) and the second bearing ring (130); at least one volume compensation element (400) comprising a housing (410), a sealing element (430), an opening (490) in the housing (410) and a further opening (500), the housing (410) being formed to to be fastened to a bearing ring (120), wherein the sealing element (430) a first partial volume (470) of an inner volume (440) of the housing (410) from a second partial volume (480) of the inner volume (440) of the housing (410) seals wherein the opening (490) in the housing (410) is arranged and adapted to fluidly access the first sub-volume (470), the further opening (500) being arranged and configured to surround the second sub-volume (480 ) and in which the housing (410) and the sealing element (430) are designed to change the volume d during a pressure change and / or a volume change of the first partial volume (470) causing the second sub-volume (480), wherein the volume compensation element (400) on the first bearing ring (120) is mechanically fixed and in the interior (250) of the bearing (100) is arranged so that one of the compensating element (400) not occupied volume of the interior (250) of the bearing (100) is fluidly coupled to the first sub-volume (470) of the volume compensation element (400); wherein the first bearing ring (120) has a vent passage (510) fluidly coupled to a pressure reservoir; and wherein the further opening (500) of the at least one volume compensation element (400) is arranged and designed in such a way to fluidly couple the second partial volume (480) to the pressure reservoir via the ventilation channel (510).

Description

Embodiments relate to a volume compensation element, a bearing and a method for reducing a pressure change in a bearing upon a change in an operating parameter of the bearing. Such a bearing may, for example, be a bearing of a vehicle, for example a wheel bearing or a wheel bearing unit of a motor vehicle.

In many areas of machine, plant and vehicle construction, the technical challenge arises of moving parts and objects moving relative to one another. In this case, a possible low-friction, ideally even frictionless movement of the involved components or objects to each other along a direction of movement to be enabled, whereas along a deviating from this direction other movement direction of the one component or object to the other component or object forces should be transferable. Such a guide can be done for example by a warehouse. In the case of a bearing for a rotational movement, for example, a rotational movement of the mechanically mechanically coupled to the bearing components about a rotation axis friction, ideally even completely frictionless, while through the bearing, for example, along a perpendicular to the axis of rotation radial forces to guide the components are transferable to each other.

Bearings are used here in a variety of configurations for guiding a wide variety of movement. Likewise, they are used at different levels of stress, temperatures, environmental conditions and other operating parameters. For example, seals are used in bearings which, depending on the specific boundary condition of the subsequent use, are intended to prevent the ingress of water, dirt and other foreign substances as well as leakage of lubricants. An interior of such a bearing can be sealed by one or more bearing seals of its environment.

An example of this are wheel bearings or wheel bearing units, so-called lifting units, in the automotive sector. Wheel bearings are in this case operated in part in very different operating states, which can be associated with different temperatures.

This can now have the consequence that also in some cases very different pressures and pressure conditions can prevail in an interior of such a wheel bearing or a corresponding wheel bearing unit. These can have a considerable influence on the functionality and functions of the seals and bearing seals used and run counter to the function of the seals. For example, if there is an overpressure in the interior of such a bearing, there may be a risk in the case of a grease-lubricated bearing that this is carried out of the unit. On the other hand, at a negative pressure in the interior of the bearing, a contacting sealing lip can be heavily loaded to promote wear. Likewise, it may be complementary or alternative that water and / or other contaminants are carried into the unit in question.

Conventionally, the seals used are pressed onto the running surfaces by high pressure loads on their main lip. Likewise, conventional attempts by an increased number of such sealing lips, the corresponding seal designed resistant to corresponding pressure differences. That this does not lead to the desired results to the full extent, is shown again and again in wastewater tests. Also, the water content of greases from already in operation camps shows a penetration of water into the corresponding camp.

The DE 10 2007 038 604 A1 refers to a bearing with at least one inner ring and at least one outer ring, wherein a space between the bearing rings is fluidly connected to a device for pressure equalization. This is connected as an external unit to a corresponding bearing ring.

However, such a construction is often difficult or impossible due to confined space and a possible undesirable interaction with components of the bearing or other components of a system comprising the bearing. There is therefore a need to improve a compromise between increased reliability of a bearing, reduced space requirements and easier implementation.

The US 5,303,800 refers to a closed lubricant system for a wheel hub bearing. The GB 2 058 244 A describes a bearing assembly, the JP H 4-108002 an efficiency enhancing device for a front axle hub, the DE 7 524 907 U a housing for rolling and sliding bearings, the JP 2011074939 A a storage device and the DE 198 14 214 A1 a machine element with hydraulic filling, in particular a bearing or a shaft. The JP 2011-190910 A refers to a storage device for a wheel that US 3,007,751 on a lubrication device that US 4,200,343 on a sealing system for a drill bit, the US 5,492,393 to a hub cap valve device and the DE 10 2004 052 684 A1 on a bearing assembly.

This requirement is borne by a bearing according to claim 1.

A volume compensation element according to an embodiment comprises a housing which is designed to be fastened to a bearing ring of a bearing. It further comprises a sealing element sealing a first sub-volume of an inner volume of the housing from a second sub-volume of the inner volume of the housing, an opening in the housing arranged and adapted to make the first sub-volume fluid accessible from outside the housing. and a further opening which is arranged and designed in such a way as to render the second subvolume accessible in terms of fluid technology and to be able to be fluidly coupled to a pressure reservoir. The housing and the sealing element are in this case designed to effect a change in volume of the second partial volume in the event of a change in pressure and / or a change in volume of the first partial volume.

A volume compensation element according to an exemplary embodiment is thus based on the finding that a compromise between increased operational safety, smaller space requirement and easier implementation can be improved by dividing the inner volume of the housing into a first subvolume and a second subvolume by the sealing element, which in turn are sealed to each other, but wherein the first and the second sub-volume fluidly accessible from outside the housing, the first sub-volume can be coupled via the opening fluidly with an interior of the bearing and the second sub-volume via the further opening with a pressure reservoir. This makes it possible, for example, to achieve a pressure compensation at least partially with the pressure reservoir, which is adjusted for example by changing operating parameters of a camp, so for example caused by a change in the temperature of the camp or its surroundings, without the interior of the camp with the Pressure reservoir directly fluidly to couple. A leakage of lubricant and / or an entry of impurities such as foreign substances (eg water, dirt and the like) can thereby be avoided if necessary. At the same time, this may optionally reduce an additional load on the bearing seals of a bearing and thus, if appropriate, the operation of such a bearing can be designed to be more secure. Likewise, by implementing the internal volume in the interior of a housing, the additional space requirement can be reduced, and due to the geometrically clear conditions, an easier implementation of such a volume compensation element can be made possible.

The sealing element can be carried out in this case essentially gas and liquid-tight. The effect of causing the change in volume of the first and the second sub-volume can be done for example by a deformation, a change in position, a shift or another example, mechanical change of a shape or position of the sealing element. The sealing element may in this case be arranged essentially in an interior of the housing, that is to say in the interior volume. However, it may also be connected to a relative to the inner volume outer part of the housing with this. Thus, if appropriate, the sealing element can also be arranged outside the inner volume in a fastening region. The housing can here - apart from the opening and possibly other openings - completely enclose the inner volume. Optionally, the housing may in this case be designed to be in contact with just one bearing ring, wherein this bearing ring may be formed, for example, in one or more parts. For example, in the case of a two- or multi-row bearing with a corresponding number of rows of rolling elements, a plurality of partial bearing rings can optionally be provided for one or more rows of rolling elements. Basically, in this case, the volume compensation element or its housing can be attached to the bearing ring by means of any bonding techniques on the bearing ring. Optionally, however, it can be fastened at least partially by way of a frictional connection parallel to the bearing ring, as a result of which, if appropriate, easier assembly and thus easier implementation of the volume compensation element can be possible.

A frictional or frictional connection comes about through static friction, a cohesive connection by molecular or atomic interactions and forces and a positive connection by a geometric connection of the respective connection partners. The static friction thus generally requires a normal force component between the two connection partners.

The pressure reservoir can be, for example, an environment, an environment or even the atmosphere. As a result, it may thus be possible to reduce or even prevent an increase or decrease in a pressure in the second subvolume and, if appropriate, also to reduce or to increase or decrease the pressure in the first subvolume and thus in an interior of a bearing Prevent, without an entry of foreign substances or a discharge of a lubricant amount in purchasing to have to take. By thus possibly prevailing in the interior constant pressure conditions may thus be achieved if necessary, a more consistent performance or performance of the camp.

Additionally or alternatively, in a volume compensation element according to an embodiment, the internal volume may be substantially constant. In this way, it may possibly be possible to allow an arrangement of the volume compensation element in an inner of the bearing, since defined by the housing and the interior of this substantially enclosed inner volume defined external dimensions. It may thus possibly be possible to reduce a risk of obstruction of other components of the bearing, for example, the rolling elements in interaction with the raceways of the bearing rings, and so on the one hand to facilitate implementation and on the other hand to increase operational safety. Thus, optionally, the housing can be embodied substantially dimensionally stable, for example.

Optionally, the housing may include at least one side member and a cover member, wherein the side member may comprise the opening for fluidly accessing the first sub-volume. The sealing element may in this case be connected to the side component at a connecting portion of the sealing element with the side member. As a result, it may be possible to provide the volume compensation element with structurally simple means.

The connection between the side member and the sealing element can be implemented rigidly or mechanically firmly, for example. However, the sealing element may, for example, also be mechanically displaceable, that is to say, for example, be frictionally connected to the side component, the cover component or the housing. In principle, any connection technology can again be used here. Thus, for example, a frictional, a positive, a material or any combination of these connection techniques can be used. Thus, for example, a corresponding connection can be made by gluing or vulcanization of the sealing element. A frictional contact or a frictional connection is when two objects frictionally contact each other, so that between them a force in the case of a relative movement perpendicular to a contact surface between them arises, which allows a transmission of a force, a rotational movement or a torque. In this case, for example, a relative movement of the components involved may occur to each other.

Additionally or alternatively, the side member and the cover member in this case, for example, be sealed against each other. This can be done for example via a static and / or touching housing seal. Optionally, such a housing seal can be formed or carried out at least partially or completely by the sealing element.

Additionally or alternatively, the cover component may be in contact with the sealing element on a side of the connection section facing away from the side component in a contact region. Likewise additionally or alternatively, the sealing element may have a rubber coating at least in the contact region, by which it may be possible to achieve an improvement in a compromise between adhesion of the sealing element and easier mounting of the same. A gumming can for example be based on natural rubber and / or synthetically produced rubber grades.

Additionally or alternatively, the side member may comprise at least a first leg, with which the sealing element is connected at its connecting portion. Optionally, the side member may have a second leg that is substantially opposite and parallel to the first leg. By way of the second leg, the side component can then be mechanically fastened, for example, to the bearing ring. Thus, optionally, the side member may be configured substantially U-shaped or with a U-shaped cross section in the case of a substantially relative to a rotational axis of the bearing or the housing. The same may also apply to a second side member, which may also be included in the housing or forms this with. Thus, the housing may optionally be configured, for example, rotationally symmetrical with respect to an axis of symmetry which may coincide with the axis of rotation of the same in an installed, installed or integrated state in the bearing.

For example, a component may have n-fold rotational symmetry, where n is a natural number greater than or equal to 2. An n-fold rotational symmetry is present when the component in question, for example, about a rotational or symmetry axis by (360 ° / n) is rotatable and thereby merges substantially in terms of form in itself, ie with a corresponding rotation substantially to itself in the mathematical sense is mapped. In contrast to this, in a complete rotationally symmetrical design of a component in any rotation about any angle about the axis of rotation or symmetry, the component substantially transits itself into itself in terms of its shape so in the mathematical sense essentially imaged on itself. Both an n-fold rotational symmetry as well as a complete rotational symmetry is referred to here as rotational symmetry.

The volume compensation element can also be designed to be complementary or alternatively, in order to be sealed in a fastened to the bearing ring state relative to the bearing ring. This seal against the bearing ring may optionally be configured static and / or touching. It can be done for example via the sealing element. The sealing element can thus optionally and alternatively optionally be designed and arranged to seal the volume compensation element in the state fixed to the bearing ring relative to the bearing ring. In this way, it may be possible, with structurally simple means, to create a seal and / or a fastening or connection or connection of the volume compensation element with respect to or on the bearing ring.

The connection can for example be made optionally on the second leg. Herbei the sealing element may optionally be connected to the second leg so that the seal against the bearing ring is at least partially formed by the sealing element or takes place. Again, a corresponding connection in principle, in turn, by any connection technique that is applicable to the materials and forms concerned, take place. Thus, here too, a frictional, cohesive, form-fitting or any combination of the corresponding connection techniques can be used. Thus, the connection in question can also take place here, for example, by gluing or by vulcanization or vulcanization.

Here again, the sealing element can optionally have a rubber coating at least in a region on which the volume compensation element can be fastened to the bearing ring. This also makes it possible, in turn, if necessary, to achieve an improvement in a compromise between the adhesion of the seal and the mountability of the volume compensation element.

Optionally, a volume compensation element according to an embodiment, in addition or alternatively to the embodiments described above, of course, also another side member and - independently thereof - optionally also include another sealing element, which may be implemented as well as the side member or the sealing element, but also deviating from this , The cover component can be implemented, for example, as a ring or as a hollow cylinder. Here, if appropriate, either the one or more side components as well as the cover component may be made of a metallic material, for example a metal, a metallic alloy or else an alloy with non-metallic constituents, or else a plastic, for example an injection-moldable plastic.

Additionally or alternatively, in a volume compensation element according to an embodiment, the housing and the sealing element may be formed so that a maximum proportion of the internal volume of the housing of at least 30% is ingestible by the first partial volume. In this way, it may possibly be possible to provide, in a wider range, possible operating parameter fluctuations of comparable operating parameters through the use of the volume compensation element. In this case, the compensation over the possible operating parameter fluctuations tends to be possible, the greater the aforementioned ratio. Thus, in a volume compensation element according to one embodiment, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 85% maximum can be occupied by the first sub-volume of the inner volume of the housing.

Through the use of the sealing element, the ratio of the first partial volume to the second partial volume may be different. In other words, the housing and / or the sealing element may be configured such that the first partial volume and the second partial volume assume different proportions to the internal volume of the housing in the case of different operating states of the volume compensation element.

In this case, the first subvolume may optionally be divided into two or more first subvolumes of the first subvolume, which may, for example, be offset from one another along a rotational or symmetrical axis. In other words, the first subvolume may include and / or be formed by a plurality of first subvolumes. The first subvolumes need not be included mathematically in a parent contiguous volume. A volume or other quantity is related to another volume or set, if a continuous line, which in turn can deviate from a straight line in the mathematical sense, leads from one volume to the other without cutting another volume.

Additionally or alternatively, in a volume compensation element according to one embodiment, the housing and the sealing element may be formed so that through the second sub-volume, a maximum proportion of the internal volume of the housing of at least 70% is ingestible. As a result of this, it may also be possible to allow comparable or more consistent operating parameters through the use of the volume compensation element according to an exemplary embodiment over a larger operating parameter fluctuation range. Again, it is true that this is correspondingly greater with increasing proportion. Thus, in the case of a volume compensation element according to an exemplary embodiment, the maximum proportion of the second partial volume to the inner volume of the housing may be, for example, at least 75%, at least 80% or at least 85%. Independently of this, a sum of the first partial volume and the second partial volume may correspond to an internal volume of the housing. Depending on the specific embodiment, a deviation from the aforementioned sum by an intrinsic volume of the housing or an intrinsic volume of the sealing element may occur.

In this case, the second subvolume may optionally also be divided into two or more second subvolumes of the second subvolume, which may, for example, be arranged offset from one another along a rotational or symmetrical axis. In other words, the second subvolume may include and / or be formed by a plurality of second subvolumes. The second subvolumes need not be included mathematically in a superordinate coherent volume.

Additionally or alternatively, in a volume compensation element according to one embodiment, the sealing element comprise a rolling diaphragm or a long-stroke rolling diaphragm. Through the use of such a sealing element, it may be possible to allow a larger volume change with a low wear, as it can be caused for example by friction. A rolling membrane or a long-stroke rolling membrane may in this case comprise a thin-walled, sensitive special membrane made of a rubber-elastic material with or without a corresponding tissue reinforcement. Rolling membranes and long-stroke rolling membranes can thus provide a low membrane thickness and a large membrane height in relation to their diameter. This may make it possible, if necessary, to achieve a low, substantially constant over the entire stroke adjustment. When compared to conventional membranes of the same diameter, larger stroke lengths may also be achievable. Likewise, if necessary, constant effective areas can be achieved over the entire stroke. Likewise, optionally, an additional adjustment resistance when starting or when changing the direction of movement omitted, as well as a detent point in a working area of such a rolling diaphragm. Rolling membranes can be implemented, for example, based on nitrile butadiene rubber (NBR) with or without a fabric reinforcement, for example a polyester fabric. Rolling membranes of silicone rubber, fluororubber and ethylene-propylene-diene rubber (EPDM) may also be implemented with or without appropriate fabric reinforcement.

A bearing according to an embodiment comprises a first bearing ring and a second bearing ring, as well as at least one row of rolling elements arranged between the first bearing ring and the second bearing ring. Furthermore, it has at least one bearing seal, which seals an inner space of the bearing between the first bearing ring and the second bearing ring, and at least one volume compensation element according to an embodiment, which is mechanically fastened to the first bearing ring and is arranged in the interior of the bearing such that a volume of the interior of the bearing not occupied by the compensating element is fluidly coupled to the first partial volume of the volume compensating element. The first bearing ring also has a ventilation channel, which is fluidly coupled to a pressure reservoir. The further opening of the at least one volume compensation element is in this case arranged and designed to fluidly couple the second partial volume via the ventilation channel with the pressure reservoir.

A bearing according to an exemplary embodiment is thus based on the finding that the aforementioned compromise between increased operational reliability, smaller space requirement and easier implementation can be improved by implementing a volume compensation element according to an exemplary embodiment. Due to the possibility of pressure equalization with the pressure reservoir, which provides the volume compensation element, if necessary, the reliability of the bearing can be increased. By using a housing with an internal volume, which is subdivided by the sealing element into a first subvolume and a second subvolume, it is optionally possible to reduce the space requirement and thus facilitate implementation. Additionally or alternatively, if necessary, a more constant pressure can be provided in the interior of the bearing. If appropriate, this can lead to more constant operating conditions prevailing in the interior of the bearing, as a result of which the operational reliability can optionally be further increased.

In this case, a fluid-technical coupling is understood as meaning a gas-permeable or gas-conducting and possibly optionally additional liquid-permeable or liquid-conducting connection of corresponding volumes. Liquid dampers and / or liquid mist can - depending on the design of the bearing and its components and the droplet sizes - be attributed to the liquids or the gases. As has already been explained above, the pressure reservoir can be formed, for example, optionally by an environment of the bearing, for example also by the atmosphere.

Thus, in a bearing according to one embodiment, the volume compensation element can thus be arranged completely in the interior of the bearing. The bearing can be made in this two or more rows. The two- or multi-row bearing can thus comprise a corresponding number of rows of rolling elements. Depending on the specific implementation of the first and / or the second bearing ring can be made in several parts here.

In the case of a two-row or multi-row bearing, the volume compensation element may optionally be arranged between two adjacent rows of rolling elements. The bearing can be a rolling bearing with spherical, cylindrical, needle-shaped, barrel-shaped or frustoconical rolling elements. The bearing can hereby be implemented as a radial bearing, angular contact bearing or thrust bearing. The first and / or the second bearing ring can in this case be designed in one piece as well as in several parts. In the case of a two-row or multi-row implementation of a bearing, the relevant rows of rolling elements can be implemented, for example, in the context of an X arrangement, in the context of an O arrangement, in the context of a tandem arrangement or else as a mixed arrangement. For example, a bearing according to an exemplary embodiment can be, for example, a wheel bearing for a land, air or water vehicle, for example a passenger car, a lorry, a commercial vehicle, a tractor, a construction machine or a rail vehicle. Likewise, of course, more than one bearing seal can be used independently of the implementation-specific details mentioned above, which can be arranged for example on opposite end sides of the bearing.

The ventilation channel may optionally comprise a radially extending channel section in the first bearing ring. If the first bearing ring is an inner ring, the channel section can, for example, run radially inwards starting from the interior of the bearing. If, on the other hand, the first bearing ring is an outer ring, then the radially extending channel section can extend radially outwards starting from the inner space of the bearing.

Optionally, the ventilation duct may optionally further comprise an axially extending channel section in order to enable a fluidic connection with an end face of the bearing and / or the first bearing ring. Optionally, the first bearing ring may in this case be sealed on a further end face of the first bearing ring opposite the end face. Again, the seal may optionally be made touching and / or static. This can be done using technically simple means, for example via an O-ring.

Optionally, in a bearing according to one embodiment, the venting channel and / or the volume compensating element may comprise a blocking element configured to be gas-permeable but liquid-impermeable. This may make it possible, if necessary, to prevent ingress of liquids and any impurities dissolved therein, which can lead to damage or premature aging of the bearing or its lubricant. Thus, it may be possible, if necessary, to reduce or completely eliminate an entry of water into the interior of the bearing, as a result of which, if appropriate, a tendency to rust formation can be reduced. Such a blocking element may for example comprise a felt, but also an at least partially open-pored foam having a pore diameter which is smaller than a typical diameter of a droplet of a corresponding liquid.

Additionally or alternatively, in a bearing according to one embodiment, the volume compensation element occupy at least 20% of a free volume of the interior of the bearing. This may make it possible to reduce the volume of gas contained in the warehouse. In this way, if necessary, with changing operating parameters, that is to say, for example, with changing temperature, an effect of this change on the pressure conditions prevailing in the bearing can be reduced. In other embodiments, it may be advisable to have at least 25%, at least 30%, at least 35%, at least 40%, at least 45% or at least 50% of the free volume of the interior occupied by the volume compensation element.

In this case, the free volume is understood to be the volume of the interior of the bearing occupied by a gas, gas mixture, a liquid and / or a lubricant in an operable state thereof, that is to say the components required for operation Bearings are mounted. These include, for example, the bearing seals, the rolling elements and, if such is provided, the one or more bearing cages. The volume of the volume compensation element may in this case comprise the volume enclosed by the housing, that is to say the complete inner volume with the first and the second partial volume, but also optionally the volume occupied by the housing itself, the sealing element and optionally further implemented components of the volume compensation element.

A method according to an embodiment for reducing a pressure change in a bearing upon a change of an operating parameter of the bearing comprises effecting a volume change of a second partial volume of an internal volume at a pressure change caused by the change of the operating parameter of the bearing and / or a volume change of a first partial volume of the internal volume , The internal volume is in this case arranged in the interior of the bearing. The first subvolume is sealed by the second subvolume and fluidly coupled to an interior of the bearing with a volume of the interior of the bearing not occupied by the interior volume. The second subvolume is fluidly coupled to a pressure reservoir. The inner volume may in this case represent or include, for example, the common inner volume of a compensating element. The internal volume can in this case be arranged completely in the interior of the bearing. This can be effected for example by a volume compensation element according to an embodiment.

A method for reducing a pressure change in a bearing when changing an operating parameter of the bearing according to an embodiment is also based on the finding that the compromise mentioned above by the provision of the first and the second sub-volume and the possibility of effecting the volume change between the first and the second sub-volume can be optionally improved.

Both in a volume compensation element according to an embodiment, as well as in a bearing and the method for reducing a pressure change in a bearing upon a change of an operating parameter, the features and implementations described above can be implemented independently in different embodiments. Arbitrary combinations of corresponding features and implementations are therefore possible within the scope of corresponding exemplary embodiments, unless something else implicitly results from the technical context. A mechanical coupling of two components comprises both direct and indirect coupling.

Hereinafter, embodiments will be described and explained in more detail with reference to the accompanying drawings.

1 shows a cross-sectional view through a bearing according to an embodiment with a volume compensation element according to an embodiment;

2 shows a further cross-sectional view through the in 1 shown bearings with one opposite 1 inclined cutting plane; and

3 shows a flowchart of a method for reducing a pressure change in a bearing at a change of an operating parameter of the bearing.

In the following description of the accompanying drawings, like reference characters designate like or similar components. Further, summary reference numbers are used for components and objects that occur multiple times in one embodiment or in one representation, but are described together in terms of one or more features. Components or objects which are described by the same or by the same reference numerals may be the same, but possibly also different, in terms of individual, several or all features, for example their dimensions, unless otherwise explicitly or implicitly stated in the description.

As already briefly explained above, in the case of many designs in the field of mechanical engineering, plant construction and vehicle construction, the challenge arises that, when bearings are mounted on components and components which move relative to one another, they are supported by bearings, for example due to the prevailing conditions Operating and / or environmental conditions to be operated sealed. An example of this are wheel bearings of motor vehicles, such as passenger cars, trucks, commercial vehicles, tractors and other corresponding vehicles. Embodiments of a volume compensation element, a bearing and a method for reducing a pressure change in a bearing in a change of an operating parameter of the bearing are by far not limited to such wheel bearings or the aforementioned applications. Rather, they can in principle always be used, for example, if a corresponding guidance of components to each other necessary or advisable. Even if, in the further course, a wheel bearing is described essentially as a bearing, exemplary embodiments also include other bearings and corresponding systems, which also originate from other areas of mechanical engineering, plant construction and vehicle construction.

In a wheel bearing or a corresponding wheel bearing unit, which is also referred to as a hub unit, seals are used in bearings that serve, on the one hand, penetration of water and dirt on the one hand and on the other hand leakage of introduced in the bearing or the bearing unit lubricant prevention. As a lubricant in this case both grease-based lubricant, as well as oil-based or solid-based lubricant can be used. Due to very different operating conditions and environmental conditions bearings can be subjected to very different operating parameters and operating conditions, which can lead to very different temperatures of the bearing. This can have the consequence that in an interior of such a bearing unit or a corresponding bearing also different pressures can prevail, which may possibly oppose the function of the bearing seals. So there is an overpressure tends to risk that the lubricant, so for example, the fat is carried out of the camp, while at a negative pressure, a sealing lip of a bearing seal can be heavily burdened wear. Additionally or alternatively, water and / or dirt can also be entered into the bearing.

As the following discussion will show, embodiments are based in part at least on providing sub-volumes through which a reduction in pressure change in an interior of such a bearing can be reduced. This can be done for example by the integration of a volume compensation element according to an embodiment in a corresponding bearing according to an embodiment. This may make it possible, if necessary, to allow overpressure or underpressure-free or corresponding overpressure or low-pressure operation of a bearing and its seals. Without or with a reduced pressurization so the seals of the bearing (bearing seals) may optionally be performed lighter, creating a reduced frictional torque is generated by the bearing seals. Here, for example, relevant fuel savings can be achieved in the automotive sector, for example. Bearings according to an embodiment can be operated in turn cooler, for example, with their grease filling as a lubricant, which can increase the grease life and thus the bearing life. In addition, there is the possibility that the entry of ambient media may optionally also be reduced, which may again increase the bearing life if necessary.

1 shows a cross section through a bearing 100 according to an embodiment, which is for example a wheel bearing 110 can act. The warehouse 100 includes a first bearing ring 120 and a second bearing ring 130 which is an inner ring 140 and an outer ring 150 is. The warehouse 100 further comprises at least one row 160 of rolling elements 170 between the first and the second bearing ring 120 . 130 are arranged. More specifically, it is in the in the 1 and 2 shown bearings 100 around a two-row bearing with two rows 160-1 . 160-2 of rolling elements 170 , The rolling elements 170 stand here with appropriate careers 180 in contact and roles in these at a relative movement of the first bearing ring 120 to the second bearing ring 130 around a rotation axis 190 from. The rolling elements 170 one of each row 160-1 . 160-2 is in this case by a Wälzkörperkäfig or cage 200-1 . 200-2 guided. Through the use of cages 200 become the rolling elements 170 kept at a distance and substantially equidistant around the circumference about the axis of rotation 190 distributed around.

The rolling elements 170 are frustoconical in this case and at a symmetrical angle to the axis of rotation 190 aligned, however, for the rolling elements 170 the two rows 160-1 . 160-2 with regard to their orientation or inclination. The rolling elements 170 the two rows 160-1 . 160-2 are more precisely arranged in an O-arrangement. Corresponding are the raceways 180 opposite to an axial direction, with the axis of rotation 190 coincides or runs parallel to this, inclined.

Of course, in other embodiments of a bearing 100 also more or less rows 160 of rolling elements 170 be used. Likewise, the rolling elements 170 also different from the truncated cone shape, for example, as spherical, cylindrical, needle-shaped or barrel-shaped rolling elements 170 be implemented. Depending on the specific shape of the rolling elements 170 can also raceways 180 in terms of their geometric configuration and their arrangement, that is, for example, their inclination relative to the axis of rotation 190 to be different. The rolling elements 170 as well as the bearing rings 120 . 130 may be made of one or more metallic materials, such as a metal, a metallic alloy or an alloy with non-metallic constituents. So can the rolling elements 170 as well as the bearing rings 120 . 130 be made for example from a bearing steel. The cages 200 that are themselves More specifically, optional components may be made of, for example, a plastic, an injection moldable plastic, but also a metal or other metallic material.

At the in 1 and 2 shown bearings 100 it is a double-row bearing in which the outer ring 150 , so the second bearing ring 130 is designed in one piece and according to the careers 180 for both rows 160-1 . 160-2 the rolling elements 170 includes. In contrast to this is the inner ring 140 So the first bearing ring 120 , designed in two parts and correspondingly has a first part ring 210-1 and a second sub-ring 210-2 on, at a mid-level 220 of the bearing abut each other, but in other embodiments may also be separated from each other by another component, but may still be arranged adjacent to each other. The two partial rings 210 have in the embodiment shown here a bearing 100 in the area of the middle levels 220 Thus, each abutment surfaces, which rest along the axial direction to each other. Of course, in other embodiments of a bearing and the partial rings 210 at one of the median plane 220 abut each other deviating position. In other words, the partial rings 210 possibly be designed asymmetrically divided.

To get out of the two partial rings 210-1 . 210-2 a common inner ring 140 as the first bearing ring 120 To form, the two partial rings point 210 in the area of the median plane 220 one recess each 230-1 . 230-2 in which a connection clamping ring or a connection clip 240 engages and the two partial rings 210 connects with each other. This will be the camp 100 self-sustaining and stable.

Between the first bearing ring 120 and the second bearing ring 130 is an interior 250 arranged by the aforementioned components of the warehouse 100 So, for example, the rows 160 the rolling elements 170 as well as the cages 200 are arranged. On the one hand, the penetration of water and dirt into the interior 250 of the camp 100 to prevent and on the other hand leakage of a lubricant, such as a grease from the interior 250 of the camp 100 To prevent, the bearing has at least one bearing seal 260 More precisely, the bearing points 100 as it is in the 1 and 2 shown is a first bearing seal 260-1 on a first front side 270-1 of the camp 100 or the first bearing ring 120 on, which is more specifically a cover plate 280 is. At one of the first end 270-1 opposite second end face 270-2 has the warehouse 100 a second bearing seal 260-2 in the form of a cassette seal 290 on while the cover disk 280 essentially serves to escape the grease from the interior 250 of the camp 100 to prevent, allows the cassette seal 290 a gas-tight and fluid-tight seal of the interior 250 ,

This is how the cassette seal points 290 a reinforcing structure 300 that with the second bearing ring 130 mechanically, for example, is positively connected, and a counter-rotating ring 310 on, to the one sealing lip 320 an elastomeric structure 330 rests with the reinforcing structure 300 mechanically cohesively, for example, is connected by a scorching. The sealing lip 320 is spring-loaded via a spring ring and presses the sealing lip 320 against the mating ring 310 , which in turn frictionally with the first bearing ring 120 that is the inner ring 140 connected is. The elastomer structure 330 also has an axial sealing lip 340 on, which also against the L-shaped mating ring 310 presses and another radial sealing lip 350 on, which is directly against the inner ring 140 or the first bearing ring 120 suppressed.

Of course, in other embodiments, the bearing seals 260 be designed differently. Depending on the specific implementation, it may possibly be possible, even only one, possibly more than two bearing seals 260 provided.

Regardless of the exact design of the camp 100 Depending on the operating and environmental conditions, it may now happen that the bearing 100 operated at higher or lower temperatures. As a result, it can happen that in the interior 250 located gas or gas mixture seeks to expand and so a pressure in the interior 250 increases. This can lead to a load on the sealing lips 320 . 340 . 350 the bearing seals 260 come. Now to the previously described effect of reducing the pressure changes in the interior 250 of the camp 250 to achieve that points in the 1 and 2 shown bearings 100 a volume compensation element 400 on. This is symmetrical and central to the median plane 220 that is, between the two adjacent rows 160-1 . 160-2 of rolling elements 170 arranged. Adjacent are two objects, between which no further object of the same type is arranged. Immediately adjacent are corresponding objects when they are adjacent, that is, for example, in contact with each other.

Because the volume compensation element 400 has a housing 410 which is just able to on one of the bearing rings, more precisely on the first bearing ring 120 in which this embodiment is the inner ring 140 acts to be attachable. For others Embodiments may be in the first bearing ring 120 but also around the outer ring 150 act.

The housing 410 This is at least partially frictionally with the first bearing ring 120 However, in other embodiments, it can also be attached using other connection techniques. The housing 410 here has a first side member 420-1 and a second side member 420-2 on, which are designed substantially U-shaped. They have two accordingly along the axis of rotation 190 , ie the axial direction 190 extending leg, to each a sealing element 430-1 . 430-2 are attached. The sealing elements 430 In this case, for example, they can be designed as rolling membranes or long-stroke rolling membranes and, for example, at one with respect to an internal volume 440 outboard section of the housing 410 or side components 420 be vulcanized. The rolling membranes are so on the outer sides of the legs of the U-shaped side members 420-1 . 420-2 vulcanized. Optionally, the sealing elements can be additionally rubberized in this area, for example, a compromise or a ratio of adhesion and ease of mounting the side members 420 to improve.

Due to their geometric shape, the side components become 420 Also referred to as U-plates, although they are actually formed only in cross-section U-shaped. Rather, it is a cup-shaped ring structures having a corresponding U-shaped cross-section.

At a radially inner area are the side members 420 over the sealing element 430 , which as a long-stroke rolling diaphragm 450 or Stülpmembran is configured, with the partial rings 210 of the inner ring 140 or the first bearing ring 120 connected. Order now the internal volume 440 of the volume compensation element 400 from the interior 250 to complete the camp, the housing has 410 Further, a cover member 460 on, the ring or hollow cylindrical shape is designed and with the radially outer legs of the side members 420 or the applied to these sections of the sealing elements 430 are connected. This results in the inner volume now 440 which is substantially complete with the housing 410 is enclosed. In the interior of the case 410 Here are the freely movable membranes of the sealing elements 430 arranged, which can move accordingly. The sealing elements 430 divide the interior volume 440 in sealed first partial volumes 470-1 . 470-2 and a corresponding second partial volume 480 , This show the 1 and 2 the membranes of the sealing elements 430 in its two extreme positions, namely once in the position where the membranes are substantially immediately adjacent to the side members 420 of the housing 410 abut and once as dotted lines in the state in which the membrane are deflected maximum. In the 1 and 2 Here are the first and second sub-volumes 470-1 . 470-2 . 480 in relation to the maximum deflected membranes of the sealing elements 430 provided with corresponding reference numerals.

To now a pressure equalization over the internal volume 440 or the two sub-volumes 470 . 480 to allow, the housing has 410 in the side components 420 one opening each 490-1 . 490-2 on which the first partial volumes 470-1 . 470-2 of the internal volume 440 of the housing 410 from outside the case 410 , so the interior 250 of the camp 100 from fluid technology accessible. About these openings 490 Thus, for example, in the case of heating in the interior 250 of the bearing air or another corresponding gas or gas mixture this in the first subvolume 470 penetrate and this by a corresponding deformation, displacement or other mechanical influence of the sealing elements 430 at the expense of the second partial volume 480 enlarge. The volume compensation element 400 thus provides a volume of which in the interior 250 located in the air or a corresponding other gas can be taken, so as to counteract an increase in pressure.

To equalize the pressure of the first partial volumes 470 sealed or isolated second sub-volume 480 to allow, the housing has 410 or the volume compensation element 400 another opening 500 essentially by a through the second or radially inner leg of the two side members 420 is formed. The further opening 500 thus makes it possible, even the second sub-volume fluidly from outside the housing 410 make it accessible, for example, to a pressure reservoir, for example, the environment of the camp 100 So, for example, to couple the atmosphere fluidly. For this purpose, the bearing points 100 a ventilation duct 510 on that in the in 1 shown section is visible. The ventilation duct 510 in this case has a radially inward in the region of the abutting surfaces of the partial rings 210 extending channel section 520 on that into an axial channel section 530 of the ventilation duct 510 opens, in the embodiment shown here to the second end face 270-2 runs. There it flows into a blocking element 540 which may, for example, be a felt ring or an at least partially open-pored foam having a pore diameter smaller than a typical diameter of droplets of liquids, their penetration via the barrier element 540 should be prevented. This is the blocking element 540 just like that formed so that this gas permeable, but is liquid impermeable.

In order also in the case of a radial fixation of the bearing 100 over the front sides 270 ventilation of the ventilation duct 510 ensure the bearing points 100 on the second front side 270 one to the camp 100 or the median plane 220 remote groove 550 which extends in the radial direction and in the in 2 shown section can be seen. This connects the blocking element 540 with an area typically exposed in a corresponding implementation. This is how the groove works 550 straight into a phase of the partial ring 210-2 of the inner ring 140 a, over which the bearing seal 260-2 So the cassette seal 290 is introduced.

To seal the ventilation duct 510 from the side of the second end face 270-2 opposite first end face 270-1 to achieve, for example, penetration of lubricants, water, liquids, dirt or other unintentional substances in the ventilation duct 510 and thus the second partial volume 480 To prevent, the inner ring points 140 So the first bearing ring 120 a groove 560 for receiving a corresponding seal, here for receiving an O-ring 570 on.

In the in the 1 and 2 In the embodiment shown, a cavity in the form of the volume compensation element is thus so in an interior of the storage 400 executed, which can be made for example of sheets, other metallic materials or of a plastic, such as a plastic injection moldable plastic. Apart from the sealing elements 430 includes the housing 410 Here are three parts and is composed of these accordingly. In addition to the two side components 420-1 . 420-2 , which are also referred to as U-plates, has the housing 410 so also called sheet metal ring cover component 460 on the two side components 420 each comprise one or more openings 490 , which are also referred to as vent holes on the side members 420 and the cover member 460 connect and close the two configured as membranes sealing elements 430 from. The side members have on their outsides a rubberized membrane cloth as sealing elements 430 vulcanised on the insides of the side panels 420 of the housing 410 can lie without adhesion inwards or outwards.

The maximum, variable volume, as indicated in the figures by the dashed lines shown there, can be in the inner volume or interior of the housing, which is also referred to as a sheet-metal body 410 be provided for pressure equalization. The areas on the outsides of the side members with the vulcanized rubber have on their inner diameter the optional function, with the part rings 210 of the inner ring 140 (Inner bearing rings) to produce a static seal and on the outer diameter also the optional function of a static seal against the cover member 460 , So the corresponding metal ring to produce.

It may be advisable if the volume range between the sealing elements 430 , So the membranes, an air exchange, for example, over the joint area of the partial rings 210 of the inner ring 140 and at least via an inner ring fit to an outside world (environment) allows. Optionally, a water-repellent felt ring or another blocking element can be used here 540 at one end of the bearing ring (front side 270 ) can be used, for example, to prevent rust-inducing or benefiting water can enter this volume range. Depending on the specific structural design, it may be advisable, above the blocking element on the corresponding contact surfaces or end faces 270 of the inner ring 140 one in 2 shown groove 550 to compensate for pressure or air compensation. Optionally, on the other part ring 210-1 of the inner ring 140 over one into the groove 560 introduced seal, for example in the form of the O-ring 570 to prevent media access from the outside or to be protected against it.

In the 1 and 2 is so about the volume compensation element 400 a pressure balance of a bearing unit or a wheel bearing 110 or a wheel bearing unit shown on Stülpmembranen. Embodiments may thus be based, for example, on the idea that such a system over long-stroke rolling diaphragms a pressure equalization in the region of a free space or a free volume between the raceways 180 the rolling elements 170 can allow. A corresponding sealing takes place here via the corresponding sealing elements, ie the long-stroke rolling membranes between the bearing interior and the bearing environment. Thus, an inverted membrane as a single seal between the sub-volumes 470 . 480 in the context of a compensation element 100 are used, which is then used in a warehouse, such as a wheel bearing or a wheel bearing unit.

3 Finally, shows a flowchart of a method according to an embodiment for reducing a pressure change in a bearing at a change of an operating parameter of the bearing 100 , After a start of the method in a step S100, in a step S110 a volume change of the second partial volume 480 of the internal volume 440 at one by changing the operating parameter of the bearing 100 caused pressure change and / or a change in volume of a first sub-volume 470 of the internal volume 440 causes. The internal volume 440 is here in the interior 250 of the camp 100 arranged, wherein the first partial volume 470 from the second subvolume 480 is sealed. The first partial volume 470 is here with the interior 250 of the camp 100 with not one of the internal volume 440 occupied volume of the interior 250 the bearing fluidly coupled. The inner volume can in this case a common inner volume of the volume compensation element 400 form. Subsequently, the process ends in a step S120.

Even if in the 1 and 2 a very special embodiment of a warehouse 100 and a corresponding volume compensation element 400 However, embodiments have been far from limited to this implementation. Thus, at the beginning of the description, a large number of design refinements have been described which can be implemented independently of one another in different exemplary embodiments. These not only concern concrete dimensions, but also constructive alternatives and variants.

The use of an exemplary embodiment can thus possibly be a compromise between increased operational safety of a bearing 100 , a smaller space requirement and an easier implementation.

The features disclosed in the foregoing description, the appended claims and the appended figures may be taken to be and effect both individually and in any combination for the realization of an embodiment in its various forms.

LIST OF REFERENCE NUMBERS

100

camp

110

Wheel bearings

120

first bearing ring

130

second bearing ring

140

inner ring

150

outer ring

160

line

170

rolling elements

180

career

190

axis of rotation

200

Cage

210

partial ring

220

midplane

230

recess

240

brace

250

inner space

260

bearing seal

270

front

280

cover disc

290

cassette seal

300

reinforcing structure

310

Against race

320

sealing lip

330

elastomeric structure

340

axial sealing lip

350

additional radial sealing lip

400

Volume compensation element

410

casing

420

side component

430

sealing element

440

internal volume

450

rolling diaphragm

460

cover member

470

first partial volume

480

second partial volume

490

opening

500

further opening

510

ventilation duct

520

radial channel section

530

axial channel section

540

blocking element

550

groove

560

groove

570

O-ring

Claims (8)

Camp ( 100 ) having the following features: a first bearing ring ( 120 ) and a second bearing ring ( 130 ); at least one row ( 160 ) from between the first bearing ring ( 120 ) and the second bearing ring ( 130 ) arranged rolling elements ( 170 ); at least one bearing seal ( 260 ), which has an interior ( 250 ) of the warehouse ( 100 ) between the first bearing ring ( 120 ) and the second bearing ring ( 130 ) seals; at least one volume compensation element ( 400 ), a housing ( 410 ), a sealing element ( 430 ), an opening ( 490 ) in the housing ( 410 ) and another opening ( 500 ), wherein the housing ( 410 ) is adapted to a bearing ring ( 120 ) to be fastened, wherein the sealing element ( 430 ) a first partial volume ( 470 ) of an internal volume ( 440 ) of the housing ( 410 ) of a second partial volume ( 480 ) of the internal volume ( 440 ) of the housing ( 410 ), the opening ( 490 ) in the housing ( 410 ) is arranged and adapted to the first sub-volume ( 470 ) fluidly accessible, wherein the further opening ( 500 ) is arranged and configured in such a way that the second partial volume ( 480 ) fluidly accessible and fluidly coupled with a pressure reservoir, and wherein the housing ( 410 ) and the sealing element ( 430 ) are adapted to at a pressure change and / or a change in volume of first partial volume ( 470 ) a volume change of the second partial volume ( 480 ), wherein the volume compensation element ( 400 ) on the first bearing ring ( 120 ) is mechanically fastened and in the interior ( 250 ) of the warehouse ( 100 ) is arranged so that one of the compensating element ( 400 ) not occupied volume of the interior ( 250 ) of the warehouse ( 100 ) fluidically with the first partial volume ( 470 ) of the volume compensation element ( 400 ) is coupled; the first bearing ring ( 120 ) a ventilation channel ( 510 ), which is fluidly coupled to a pressure reservoir; and wherein the further opening ( 500 ) of the at least one volume compensation element ( 400 ) is arranged and configured in such a way that the second partial volume ( 480 ) via the ventilation channel ( 510 ) to fluidly couple with the pressure reservoir. Camp ( 100 ) according to claim 1, wherein the internal volume ( 440 ) is substantially constant. Camp ( 100 ) according to one of the preceding claims, in which the housing ( 410 ) and the sealing element ( 430 ) are formed so that by the first partial volume ( 470 ) a maximum proportion of the internal volume ( 440 ) of the housing ( 410 ) is at least 30% ingestible, and / or at the housing ( 410 ) and the sealing element ( 430 ) are formed so that through the second sub-volume ( 480 ) a maximum proportion of the internal volume ( 440 ) of the housing ( 410 ) of at least 70% is ingestible. Camp ( 100 ) according to one of the preceding claims, in which the sealing element ( 430 ) comprises a rolling membrane or a long-stroke rolling membrane. Camp ( 100 ) according to one of the preceding claims, in which the housing ( 410 ) at least one side component ( 420 ) and a cover component ( 460 ), wherein the side member ( 420 ) the opening ( 490 ) for the fluidic accessibility of the first partial volume ( 470 ), and the sealing element ( 430 ) with the side component ( 420 ) at a connecting portion of the sealing element ( 430 ) with the side component ( 420 ) connected is. Camp ( 100 ) according to one of the preceding claims, in which the sealing element ( 430 ) and / or the volume compensation element ( 400 ) is adapted to the volume compensation element ( 400 ) in one on the bearing ring ( 120 ) fastened state relative to the bearing ring ( 120 ) seal. Camp ( 100 ) according to one of the preceding claims, in which the ventilation channel ( 510 ) and / or the volume compensation element ( 400 ) a blocking element ( 540 ) configured to be gas permeable but liquid impermeable. Camp ( 100 ) according to one of the preceding claims, in which the volume compensation element ( 400 ) at least 20% of a free volume of the interior space ( 250 ) of the warehouse ( 100 ) occupies.

Images