Patent Application
20100150487
This application claims priority to German patent application no. 10 2008 062 740.2, filed on Dec. 17, 2008, which is incorporated fully herein by reference.
The present invention generally relates to bearings and bearing assemblies, which may preferably be utilized in wheel bearings, e.g., truck wheel bearings, in certain applications of the present teachings.
Some known bearing assemblies for wheel bearings utilized in trucks comprise two inner rings or races having different bore diameters. A frustum-shaped connecting piece or spacer is disposed between the differently-sized inner rings and serves to set the spacing of the inner rings in the axial direction. The inner rings and spacer are mounted on a non-driven wheel axle or axle spindle having an outer shape that generally corresponds to the shape of the inner bores of the inner rings and spacer. Roller elements are disposed between the inner rings, which contact the axle spindle and do not rotate during driving, and a corresponding set of outer rings or races, thereby forming inboard and outboard roller bearings. These roller bearings enable a wheel hub coupled to a wheel to rotate about the non-driven axle spindle when the vehicle is driven.
To simplify mounting of the wheel mount on the wheel axle, the inner ring having the smaller diameter is disposed, with respect to the insertion direction of the wheel axle, on the forward or front side of the wheel mount and the inner ring having the larger diameter is disposed on the rearward side of the wheel mount. The circumferences of the wheel axle or axle spindle correspond to the bore diameters of the inner rings and the spacer, such that, during mounting of the wheel mount on the wheel axle, the segment of smaller circumference is initially guided through the larger-diameter inner ring and the spacer. This wheel mounting procedure can thus be performed in a relatively simple manner. As soon as the axle spindle segment having the smaller circumference is completely inserted into the inner ring having the smaller diameter, the frustum-shaped segment of the axle spindle is located in the corresponding frustum-shaped segment of the spacer and the segment of the axle spindle having the larger circumference is located in the inner ring having the larger diameter.
In such a three-part construction, axial shifting or displacement of the inner rings relative to the spacer may not be sufficiently restricted or prevented during the mounting procedure. Further, if the junction of the respective inner rings and the spacer is not relatively smooth, the axle spindle could bump against the spacer or the smaller inner ring during insertion into the wheel bearing assembly, which would hinder the wheel mounting procedure.
It is an object of the present invention to provide an improved bearing and/or bearing assembly.
According to a first aspect of the present teachings, a bearing assembly preferably comprises at least two axially-spaced bearings. Each bearing comprises an inner ring and the two inner rings have preferably differently-sized bore diameters. A substantially sleeve-shaped connecting piece is disposed between the two inner rings and preferably at least substantially defines the axial separation or spacing between the two inner rings. The sleeve or connecting piece may preferably have a substantially frustum, conical or tapered shape. The inner diameter at each axial end region of the connecting piece preferably corresponds to the respective inner bore diameter of the bordering or adjacent inner ring, so that contact points are defined between the connecting piece and each respective inner ring. At least one curved, or more preferably ring-shaped, fixing element is preferably utilized to fix at least one inner ring relative to the connecting piece in the radial direction. The fixing element is preferably disposed at the contact point between the connecting piece and the respective inner ring. More preferably, the fixing element at least partially overlaps the connecting piece and the respective inner ring in the axial direction of the bearing assembly. Fixing elements may be disposed at each contact point of an inner ring and the connecting piece.
In such a representative, non-limiting bearing assembly, movement or displacement of the connecting piece in the radial direction, which has been a problem of known bearing assemblies, is prevented by the fixing element(s). The connecting piece is held in position by the fixing element or fixing elements, so that, for example, a wheel axle or axle spindle can be easily inserted when the present bearing assembly is utilized as a wheel bearing. In addition, such a bearing assembly offers the possibility of being manufactured relatively inexpensively in certain applications of the present teachings.
The one or more fixing elements is/are preferably disposed radially outward of the contact points defined by the respective inner rings and the connecting piece. In such an embodiment, the fixing element also may be manufactured in a relatively simple way. Moreover, it is not necessary to alter the shape of the inner bores of the inner rings and the connecting piece. That is, the inner bores can be manufactured with smooth, continuous inner surfaces. The loading capacity of the bearing assembly is thus not impaired by requiring a section or segment of the inner ring(s) or connecting piece to be made thinner in order to accommodate a fastening or fixing element on the inside surface of the bearing assembly, as is the case with certain known bearing assemblies.
In addition or in the alternative, the connecting piece and the fixing elements may be constructed such that axial movement of the fixing elements is limited to a small range or is prevented, so that each fixing element continuously overlaps the connecting piece and corresponding inner ring during operation. In this embodiment, the fixing elements can be prevented from moving or displacing too far in the axial direction from their home positions, which excessive axial shifting would eliminate or significantly diminish the radial-fixing effect of the fixing elements. This would take place if a fixing element no longer overlaps with the inner ring associated therewith or with the connecting piece. It is not absolutely necessary that the fixing elements are completely or immovably fixed in the axial direction. Relatively small movements in the axial direction are not critical, as long as the fixing element continues to at least partially overlap the connecting piece and the associated inner ring.
In addition or in the alternative, the connecting piece may include one or more retaining elements that is/are formed so as to limit the amount of axial movement of the fixing elements or to entirely prevent axial movement of the fixing elements. In this case, the retaining elements can prevent a disadvantageous excessive axial movement of the fixing elements.
In addition or in the alternative, the connecting piece may have two radially-extending projections or “cantilever arms” and each of the fixing elements may have at least one additional radially-extending cantilever arm. The cantilever arms are respectively disposed relative to each other in a manner that prevents axial movement of the fixing elements towards the connecting piece or at least restricts an amount of axial movement that would eliminate the overlap of the connecting piece and the respective inner ring. In a preferred embodiment, as soon as the respective cantilever arms of the connecting piece and the fixing element come into contact with each other, further movement of the respective fixing element in the axial direction is prevented. It is recommended that the spacing of the cantilever arms relative to the respective edge of the connecting piece is smaller than the axial length of the respective fixing element, so that the overlap of the fixing element with the respective inner ring is always maintained.
The term ‘cantilever arm’ as utilized herein to identify a structural feature associated with the connecting piece, fixing element and/or bearing cage may be replaced or substituted, e.g., with the term ‘projection’, ‘protrusion’, ‘flange’, ‘shoulder’, ‘stop’, etc., as all such structural features may be used interchangeably in the present teachings to perform the function of preventing or limiting axial shifting of the respective components.
The term ‘connecting piece’ may also be replaced or substituted with the term ‘sleeve’, ‘journal’, ‘spacer’, ‘spacer sleeve’, etc. The connecting piece preferably serves, in part, to define an axial separation or spacing between two inner rings and to provide a hollow cavity for receiving, e.g., an axle. The connecting piece also preferably includes at least one structural feature utilized in preventing or restricting movement of the connecting piece and the inner ring(s) in the axial direction of the bearing assembly.
The term ‘fixing element’ may also be replaced or substituted with the term ‘fastener’, ‘retainer’, ‘bracket’, ‘holding ring’, ‘retaining ring’, etc. The fixing element serves, in part, to maintain the relative positions of the connecting piece and the inner ring(s) in the radial direction of the bearing assembly. In addition, the fixing element optionally includes at least one structural feature utilized in preventing or restricting relative movement of the connecting piece and the inner ring(s) in the axial direction of the bearing assembly.
The terms ‘inner ring’ and ‘outer ring’ may also be replaced or substituted with the terms ‘inner race’ and ‘outer race’, respectively.
In accordance with another aspect of the present teachings, one or more of the bearings is embodied as a roller bearing and preferably includes one or more roller bearing elements or bodies, which is/are preferably disposed between the inner ring of the bearing and an outer ring of the bearing.
In accordance with another aspect of the present teachings, at least one of the fixing elements preferably has a cantilever arm disposed on the side facing the roller bearing(s) of the associated or adjacent bearing. The cantilever arm is preferably formed so as to prevent the fixing element from contacting the roller bodies of the corresponding roller bearing. If the fixing element were to contact one or more moving roller bodies of the roller bearing during operation, it could lead to damage and thus should be prevented. One design possibility entails extending one or more of the cantilever arm(s) so as to be high enough that it/they will contact an outer ring of the respective roller bearing before contact with the roller bodies takes place. In this case, a migration of the fixing element(s) into the roller bearing(s) during operation is avoided.
In addition or in the alternative, each roller bearing preferably comprises at least one cage. In this case, the cantilever arm of the respective corresponding fixing element is preferably formed such that an axial displacement of the fixing element towards or into the roller body is prevented by contact between the cage and the cantilever arm. In this case, the contact of the fixing element with the roller bodies can be prevented in a simple way, because as soon as one of the fixing elements comes into contact with the corresponding cage, a further penetration into the roller bearing is prevented.
In addition or in the alternative, the one or more fixing elements may be embodied as sheet metal rings preferably having a U-shaped profile in radial cross section. Such structures can be manufactured particularly simply and cost-effectively. In this embodiment, the cantilever arms of the fixing elements may be formed by the perpendicularly-extending flanks or projections or shoulders of the sheet metal ring and preferably serve to ensure that the connecting piece does not shift too far in the axial direction relative to the inner ring(s).
In another aspect of the present teachings, the connecting piece and the fixing element(s) may be formed such that axial movement of the fixing elements relative to the connecting piece and the inner rings is prevented. In this case, no movement clearance is provided to the fixing elements, so that they are fixed relative to the inner rings and the connecting ring. In such an embodiment, the connecting piece preferably has at least two recesses facing the respective fixing elements and each fixing element has at least one radially-inward-extending projection that engages with the corresponding recess such that movement of the fixing element relative to the connecting piece in the axial direction is prevented. Such an embodiment is also manufacturable at a relatively low cost.
The recesses may optionally be annular groove-shaped and the projections may be directed radially inward and extend partially or completely around the circumference of the fixing element(s). In this radially-symmetric embodiment, the mounting of the fixing elements can be particularly simple, because the mounting position is arbitrary relative to the radial orientation of the respective components.
In addition or in the alternative, a bearing assembly according to the present teachings may be a component of a wheel bearing, e.g., for usage in truck applications.
Further advantages and embodiments of the invention are derivable from the following description of exemplary embodiments together with the appended drawings.
Each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved bearings and/or bearing assemblies, as well as methods for designing, constructing and using the same. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in combination, will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Therefore, combinations of features and steps disclosed in the following detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the present teachings.
Moreover, the various features of the representative examples and the dependent claims may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings. In addition, it is expressly noted that all features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original disclosure, as well as for the purpose of restricting the claimed subject matter independent of the compositions of the features in the embodiments and/or the claims. It is also expressly noted that all value ranges or indications of groups of entities disclose every possible intermediate value or intermediate entity for the purpose of original disclosure, as well as for the purpose of restricting the claimed subject matter.
A first representative bearing assembly, which may be utilized as a wheel bearing in preferred embodiments, is illustrated in radial cross section in
The representative wheel bearing of
The roller bearings 3 and 5 are arranged so as to be spaced in the axial direction. A connecting piece or spacer 23 is disposed between the roller bearings 3 and 5. The connecting piece 23 may be in contact with the inner rings 19 and 21 and thus determine the axial spacing of the roller bearings 3 and 5. However, one or more structures, such as a sealing element discussed below, may be interleaved between the connecting piece 23 and the respective inner rings 19, 21 in certain applications of the present teachings.
The connecting piece 23 is preferably sleeve-shaped, e.g., hollow, so that the wheel axle or axle spindle or other shaft can extend through it. Further, the connecting piece 23 is preferably substantially frustum- or conical-shaped, e.g., it may be tapered, such that the bore diameter of the connecting piece decreases along the axial direction of the connecting piece. The bore diameter of the connecting piece or spacer may decrease in a continuous manner, a discontinuous manner or a combination of the two.
At the circumferentially-extending contact points 25 and 27, the respective bore diameters substantially match the respective bore diameter of the bordering or adjacent inner ring 19 or 21, respectively. In certain applications of the present teachings, the bore diameters of the inner rings 19, 21 can be slightly smaller or larger than the adjacent diameters of the connecting piece 23. In such a design, the component having the smaller bore diameter should preferably be initially disposed further forward with reference to the insertion direction of the wheel axle. In this case, no points will result within the bore that would hinder the insertion of the wheel axle due to hitting or bumping against protrusions. The connecting piece 23 can also optionally include axially-extending segments having a constant inner bore diameter and/or a constant outer diameter near each contact point 25 and 27.
A circumferentially-extending fixing element 29, 31 is preferably disposed at each respective contact point 23 and 25. In one representative embodiment, the fixing element 29, 31 may be made, e.g., from a steel sheet, e.g., by bending, and preferably has a substantially U-shaped profile in radial cross section. Each of the fixing elements 29 and 31 overlap the inner ring 19, 21, respectively, associated with it, as well as the connecting piece 23, so that a radial displacement of the connecting piece 23 relative to the inner rings 19 and 21 is prevented. Consequently, the connecting piece 23 is held in the illustrated position so that the shaft or wheel axle is insertable therein without problems.
To ensure and maintain the connecting piece 23 remains fixed in the radial direction relative to the inner rings 19, 21, the fixing elements 29 and 31 are preferably not shiftable or displaceable from the respective axial positions shown in
On the bearing side, the flank of the respective U-shaped fixing element 29, 31 is formed such that an overlap region with the respective cage 15, 17 results. A movement of the fixing elements 29, 31 towards the respective roller bearing 3, 5 is stopped upon contact of the flank of the respective fixing element 29, 31 with the respective cage 15, 17, so that the flank of the respective fixing element 29, 31 is prevented from contacting the respective roller body 11, 13.
In its axial home or middle position, the respective fixing elements 29, 31 must not be in direct contact with the respective cantilever arms 33, 35 or the respective cages 15, 17, which are merely intended to prevent the fixing elements 29 and 31 from shifting or sliding too far in the axial direction from the desired home or middle position.
In an alternative representative embodiment, the outer rings of the roller bearing may have cantilever arms that stop their movement towards the roller bearing body or bodies upon contact with the bearing-side flanks of the fixing elements.
Another representative embodiment of the present teachings is illustrated in
In the alternative, it is possible to provide the recesses in the inner rings and to arrange the respective fixing elements 101, 103 in reversed or inverted form, so that the respective projections 107, 109 engage accordingly with the respective recesses. Furthermore, it is possible to form the recesses and the corresponding projections so as to not extend completely around the circumference of the connecting piece 105 and the fixing elements 101, 103. For example, in another aspect of the present teachings, two recesses may be provided in the connecting piece on opposite sides such that the recesses only partially circumferentially extend in the radial direction. In this case, the projections on the fixing elements would then be formed to have the same dimensions as the recesses, so as to preferably snugly engage therein. In this embodiment, it is advantageous to provide recesses in the connecting piece 105 as well as in the inner rings. Then, each correspondingly-formed projection of the respective fixing element 101, 103 engages with the recesses. The fixing elements 101 and 103 may have, e.g., a bracket shape.
For the assembly of the wheel bearing, it is advantageous if the inner rings 19 and 21 also remain fixed or immovable relative to the connecting piece 23, 105 in the axial direction. For example, each fixing element can be designed to engage the connecting piece and the corresponding inner ring in a friction-fit, so that a clamping force is maintained in the axial direction after assembly of the fixing elements, which axial clamping force hinders or prevents the connecting piece and inner rings from moving relative to each other in the axial direction. In addition or in the alternative, an axial clamping force can be applied to the connecting piece and inner ring(s) before mounting of the fixing elements, e.g., by compressing the connecting piece and inner ring(s) together in the axial direction. In a further advantageous embodiment, rough surfaces can be provided on the outer surfaces of one or both of the inner rings and/or the connecting piece in the area of the overlap with the fixing elements in order to facilitate the friction fit with the fixing elements. The inner surface of the fixing elements may also be provided with a rough surface.
It can be advantageous to provide a sealing element, e.g., a rubber or synthetic material ring, at or in each contact point 25 and 27 between the connecting piece 23 and the inner rings 19 and 21, respectively. A sealing element can be utilized to seal the roller bearing elements relative to the inner bore portion for receiving the wheel axle, so that no moisture can penetrate into the roller bearing elements. In the alternative, the inner sides of the fixing elements can be coated with a sealing lacquer, so that a sealing effect results after mounting.
In each of the depicted embodiments, the fixing elements can be designed in an advantageous way, such that they have an additional cantilever arm that reaches up to the support unit 1 or the outer rings 7 and 9, respectively. In the case of the embodiment in
Due to the described construction of the bearing assembly, it is possible to make the front or terminal sides of the inner rings 19 and 21, as well as the connecting piece 23, flat, because they are not required to perform an axial-fixing function due to the particular design. Consequently, the bearing clearance can be maintained as low as possible.
A dismantling of the wheel hub for maintenance or inspection purposes may be impeded by the friction-fit of the fixing elements. In order to facilitate maintenance or inspection operations, the embodiment of
The described exemplary embodiments are not to be viewed as limiting with respect to the present teachings. A variety of alternative securing mechanisms that prevent an undesired shifting of the fixing elements in the axial direction can be readily designed by the skilled person in accordance with the present teachings without departing from the scope or spirit of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 062 740.2 | Dec 2008 | DE | national |
