Bearing arrangement and an assembly comprising such bearing arrangement

The present invention relates to a bearing arrangement (104) connectable to a shaft (102), the bearing arrangement comprising a bearing (105, 105′) comprising a plurality of rolling elements (110) arranged to rotate relative to an inner raceway (302) for said bearing arrangement; and a ring shaped contact element (114, 114′) having an extension in an axial direction thereof, the ring shaped contact element further comprising a first contact surface (402) adapted to face the plurality of rolling elements, wherein an inner diameter of the ring shaped contact element at the axial position of the first contact surface has a larger diameter in comparison to a diameter (412) of the inner raceway, such that a continuous radial gap (414) is provided in the circumferential direction between the ring shaped contact element and the inner raceway when the bearing arrangement is connected to the shaft, wherein the radial gap (414) is arranged to be provided in fluid communication with a lubricating flow channel (306) of the shaft when the bearing arrangement.

TECHNICAL FIELD

The present invention relates to a bearing arrangement. In particular, the invention relates to a bearing arrangement connectable to a shaft which is preferably provided in a transmission arrangement. The invention also relates to an assembly comprising a shaft and a bearing arrangement, a method for connecting the bearing arrangement to the shaft, a transmission arrangement and a vehicle. The invention is applicable on vehicles, in particularly low, medium and heavy duty vehicles commonly referred to as trucks. Although the invention will mainly be described in relation to a truck, it may also be applicable for other type of vehicles comprising a bearing arrangement in need of improved lubrication thereof.

BACKGROUND

In connection to low-, medium and heavy duty vehicles, also commonly referred to as trucks, a transmission arrangement is connected to a prime mover for controlling torque loads from the prime mover to the propelled wheels of the truck. The transmission arrangement comprises a plurality of transmission shafts, wherein a first shaft often comprises at least one gear wheel which is arranged in meshed connection with a gear wheel arranged on a second shaft. A bearing arrangement is often provided between the transmission shaft and the gear wheel in order to controllably connect the gear wheel to the shaft. Hence, when the gear wheel is connected to the shaft, the gear wheel will have no relative rotation to the shaft, and when the gear wheel is disconnected from the shaft, the gear wheel will have a relative rotation to the shaft.

In situations where the gear wheel has no relative rotation to the shaft, while at the same time being exposed to mesh forces, there may be an insufficient lubrication for the bearing arrangement at positions where the bearing is exposed to axial loading. This may be critical for proper functionality and durability of the bearing arrangement.

For tapered roller bearings, lubrication at these positions can be improved by, for example, increasing the cone angle of the rolling elements. However, such a solution is associated with an increased radial space of the bearing arrangement which is most often a critical parameter. For cylindrical roller bearings, the bearings transfer axial forces between end surfaces on the rolling elements and shoulders arranged on an inner and outer bearing ring thereof. Centrifugal forces will distribute lubrication to the contact area between the end surface of the rolling elements and the shoulder arranged on the outer bearing ring. However, the contact area between the end surface of the rolling elements and the shoulder arranged on the inner bearing ring may not be provided with sufficient lubrication.

There is thus a need to improve the lubrication for bearing arrangements, in particularly at interfaces where the rolling element transfer axial loads.

SUMMARY

It is an object of the present invention to provide a bearing arrangement which at least partially overcomes the above described deficiencies. This is achieved by a bearing arrangement according to claim1.

According to a first aspect of the present invention, there is provided a bearing arrangement connectable to a shaft, the bearing arrangement comprising a bearing comprising a plurality of rolling elements arranged to rotate relative to an inner raceway for the bearing arrangement; and a ring shaped contact element having an extension in an axial direction thereof, the ring shaped contact element further comprising a first contact surface adapted to face the plurality of rolling elements, wherein an inner diameter of the ring shaped contact element at the axial position of the first contact surface has a larger diameter in comparison to a diameter of the inner raceway, such that a continuous radial gap is provided in the circumferential direction between the ring shaped contact element and the inner raceway when the bearing arrangement is connected to the shaft, wherein the radial gap is arranged to be provided in fluid communication with a lubricating flow channel of the shaft when the bearing arrangement is connected to the shaft.

The wording “inner raceway” should in the following and throughout the entire description be interpreted as a surface on which the rolling elements ride. The inner raceway may be provided on an inner bearing ring. However, the inner raceway may more preferably form part of a portion of the shaft. In such a case, the bearing is provided with an inner ring integrated in the shaft. Such bearing with inner ring integrated in the shaft will be described in further detail below. Similarly, the bearing may be provided with an outer ring integrated in e.g. an inner surface of a gear wheel.

Moreover, the ring shaped contact element may have an axial extension which extends from the first contact surface in an axial direction away from the rolling elements as seen in an assembled configuration. The axial extension of the ring shaped contact element may extend to such extent that a circumferential distribution channel can be formed between the shaped contact element and the inner raceway.

Furthermore, the first contact surface of the ring shaped contact element is arranged to be in contact with the at least one of the plurality of rolling elements when the bearing is exposed to axial loading. In case the bearing comprises tapered rolling elements or cylindrical rolling elements, the first contact surface will be arranged in contact with axial end surfaces of at least a part of these rolling elements.

An advantage of the present invention is that improved lubrication to the bearing is provided. In particular, lubrication will be able to reach both the contact surface between the rolling elements and the inner raceway as well as the contact surface between the rolling elements and the first contact surface of the ring shaped contact element. By providing a gap, the circumferential distribution channel will be provided such that the lubrication will be able to flow and provide a continuous lubrication at these positions.

According to an example embodiment, a shaft connecting portion of the ring shaped contact element may be connected to the shaft when the bearing arrangement is connected to the shaft.

Hereby, the ring shaped contact element can transfer axial load from the rolling elements and into the shaft. Also, the ring shaped contact element may be arranged concentric to the shaft and the connection between the shaft connecting portion and the shaft may be such that a relative rotation there between is prevented, especially if the shaft connecting portion is press fitted to the shaft as described below.

According to an example embodiment, the shaft connecting portion of the ring shaped contact element may be intended to be press fitted to the shaft.

As stated above, by press fitting the ring shaped contact element will locate the ring shaped contact element concentric to the shaft and efficiently prevent a relative rotation between the ring shaped contact element and the shaft during operation.

According to an example embodiment, an inner diameter of the shaft connecting portion may be equal to or smaller than the diameter of the inner raceway. This may be particularly suitable when a corresponding connection portion of the shaft has a diameter which is equal to or smaller than the diameter of the raceway.

According to an example embodiment, an inner diameter of the shaft connecting portion may be larger than the diameter of the inner raceway. This may be particularly suitable when a corresponding connection portion of the shaft has a diameter which is larger than the diameter of the raceway.

Accordingly, various inner diameter dimensions for the shaft connection portion are conceivable.

According to an example embodiment, the shaft connecting portion may be arranged at an opposite axial end of the ring shaped contact element in comparison to the first contact surface. Hereby, the ring shaped contact element has an axial extension which will enclose the opening from the flow channel. This will thus further enhance the provision of a circumferential distribution channel where a continuous flow of lubrication can be supplied to the rolling elements.

According to an example embodiment, the rolling elements may be cylindrical roller bearing elements.

A cylindrical roller bearing is advantageous in comparison to a tapered roller bearing as its connection to a shaft can be simplified. In detail, a cylindrical roller bearing is advantageous to use when using an inner ring integrated in the shaft, as described further below. If using e.g. a tapered roller bearing, the shaft surface would need to be tapered. Assembly of the bearing arrangement to the shaft is simplified by using a cylindrical roller bearing as the assembly can be executed from one side of the shaft for all bearings used at the specific position.

According to a second aspect of the present invention, there is provided an assembly comprising a shaft comprising a lubricating flow channel arranged in at least a radial direction within the shaft; and a bearing arrangement connected to the shaft, the bearing arrangement comprising a bearing comprising a plurality of rolling elements arranged to rotate relative to an inner raceway for the bearing arrangement; and a ring shaped contact element having an extension in an axial direction thereof, the ring shaped contact element further comprising a first contact surface facing the plurality of rolling elements, wherein an inner diameter of the ring shaped contact element at the axial position of the first contact surface has a larger diameter in comparison to a diameter of the inner raceway, such that a continuous radial gap is provided in the circumferential direction between the ring shaped contact element and the inner raceway, wherein the radial gap is arranged in fluid communication with the lubricating flow channel of the shaft.

The wording “flow channel arranged in at least a radial direction within the shaft” should be understood to mean that the flow channel has an extension in a direction having a radial component. The extension may also have an axial component as well as a circumferential component. Hence, an inclined flow channel is conceivable and forms part of the scope of the wording.

According to an example embodiment, the ring shaped contact element, the shaft and the bearing may enclose an opening of the lubricating flow channel. Hereby, a well defined volume for the lubrication is provided. Also, the volume provides the circumferential distribution channel described above.

According to an example embodiment, the ring shaped contact element may comprise a second contact surface arranged on an axially opposite side of the ring shaped contact element in comparison to the first contact surface, wherein the second contact surface is abutting a radially protruding portion of the shaft.

The second contact surface may thus efficiently transfer the axial forces from the ring shaped contact element and into the shaft. Also, the radially protruding portion of the shaft could be a component connected to the shaft, i.e. the wording should not be construed as limited to the shaft itself.

According to an example embodiment, the inner raceway may be formed by a portion of a circumferential surface of the shaft.

By providing a bearing with an inner ring integrated in the shaft will reduce cost as less material is needed. Also, the radial dimensions of the bearing arrangement can be reduced; alternatively larger rolling elements can be used. Furthermore, a bearing with an inner ring integrated in the shaft will increase the stiffness of the shaft as the shaft can be made thicker in comparison to the use of separate inner rings for the rolling elements.

Also, when using a bearing with an inner ring integrated in the shaft, self-containing roller and cage assemblies may preferably be used.

Further effects and features of the second aspect are largely analogous to those described above in relation to the first aspect of the present invention.

Accordingly, according to an aspect of the present invention, there is provided an assembly comprising a shaft comprising a lubricating flow channel arranged in at least a radial direction within the shaft; and a bearing arrangement according to any one of the embodiments described above in relation to the first aspect.

According to a third aspect of the present invention, there is provided a ring shaped contact element connectable to a shaft provided with a bearing comprising a plurality of rolling elements arranged to rotate relative to the shaft around an inner raceway, the ring shaped contact element has an extension in an axial direction thereof and comprises a shaft connecting portion arranged to be connected to the shaft, and a first contact surface adapted to face the plurality of rolling elements, wherein an inner diameter of the ring shaped contact element at the axial position of the first contact surface has a diameter which is arranged to be larger in comparison to a diameter of the inner raceway for providing a continuous radial gap in the circumferential direction between the ring shaped contact element and the inner raceway when the ring shaped contact element is connected to the shaft, wherein the ring shaped contact element is arranged to be connected to the shaft in such a way that the radial gap is provided in fluid communication with a lubricating flow channel of the shaft.

Effects and features of the third aspect are largely analogous to those described above in relation to the first and second aspects of the present invention.

According to a fourth aspect of the present invention, there is provided a method for assembling the bearing arrangement described above in relation to the first aspect to a shaft, the method comprising the steps of connecting the bearing to the shaft at a position axially adjacent an opening of a lubricating flow channel of the shaft; and connecting the ring shaped contact element to the shaft such that a portion of the ring shaped contact element is positioned radially above the opening of the lubricating flow channel, and in such a way that a radial gap is provided in the circumferential direction between the ring shaped contact element and the inner raceway.

Hereby, a simple method for assembling the bearing arrangement to the shaft is provided.

According to a fifth aspect of the present invention, there is provided a transmission arrangement for a vehicle, the transmission arrangement comprising a shaft comprising a lubricating flow channel arranged in at least a radial direction within the shaft; and a bearing arrangement according to any one of the example embodiments described above in relation to the first aspect of the present invention.

According to a sixth aspect of the present invention, there is provided a vehicle comprising a transmission arrangement, the transmission arrangement comprising a shaft comprising a lubricating flow channel arranged in at least a radial direction within the shaft; and a bearing arrangement according to any one of the example embodiments described above in relation to the first aspect of the present invention.

It should also be readily understood that effects and features described above in relation to specific aspects of the present invention can be combined with, and are associated with the other aspects of the invention.

With particular reference toFIG. 1, there is provided a vehicle1with a transmission arrangement200and a prime mover202. The transmission arrangement200comprises an assembly100(FIG. 2) provided with a shaft102and a bearing arrangement104according to the present invention. The vehicle1depicted inFIG. 1is a truck for which the inventive assembly100and bearing arrangement104, as will be described further below, is particularly suitable for.

Turning toFIG. 2, which is a perspective view illustrating the assembly100comprising the shaft102and the bearing arrangement104according to an example embodiment. The assembly depicted inFIG. 2further comprises a gear wheel106. The gear wheel106comprises a plurality of gear teeth108. The gear teeth108are inFIG. 2depicted as straight gear teeth. It should however be readily understood that the gear teeth108may be helical such that the gear wheel106can sustain axial loads acting thereon. Furthermore, the gear wheel may also comprise clutch teeth (not shown) that are used in connection with an engaging sleeve (not shown) for connecting the gear wheel106to the shaft102, or to other parts of the transmission200.

As described, the assembly100comprises the bearing arrangement104. The bearing arrangement104is thus arranged between the shaft102and the gear wheel106. The bearing arrangement104comprises a bearing105provided with a plurality of cylindrical roller bearing elements110which are preferably arranged on a self-contained roller and cage assembly112. It should however be readily understood that the present invention is not limited to the use of cylindrical roller bearing elements. Other types of rolling elements are of course conceivable such as e.g. tapered roller bearing elements, etc. However, for simplicity, the rolling elements will in the following be referred to as cylindrical roller bearing elements. As will be described further in relation to the description ofFIG. 3, the bearing arrangement104preferably comprises a bearing105with the inner ring integrated in the shaft102and the outer ring integrated in the gear wheel106.

The bearing arrangement104further comprises a ring shaped contact element114. The ring shaped contact element114, which will be described in further detail below, is arranged to abut an end surface of the rolling elements110when the bearing arrangement104is exposed to axial loading from e.g. mesh forces from the gear wheel106. Moreover, the ring shaped contact element114is arranged in axial connection with the protruding portion (403inFIG. 4) of the shaft102or, as depicted inFIG. 2, with a protruding portion of a contact ring116which is connected to the shaft102.

In order to describe the invention in further detail reference is therefore made toFIGS. 3 and 4which are cross-sectional side views illustrating the assembly100and the bearing arrangement104in further detail. As stated above and as depicted in e.g.FIG. 3, the assembly comprises the shaft102at which the bearing arrangement104is connected, which bearing arrangement104comprising the bearing105,105′ and the ring shaped contact element114,114′. As depicted inFIGS. 3 and 4, the assembly comprises a first105and a second bearing105′, wherein the first bearing105is arranged at a left hand side and the second bearing105′ is arranged at a right hand side as seen in the figures. Similarly, the assembly comprises a first114and a second114′ ring shaped contact element arranged on the respective left and right hand sides. The bearings105,105′ comprises a plurality of cylindrical roller bearing elements110which are arranged to roll against an inner302and an outer304raceway for the bearing arrangement104. The inner raceway302is constituted by a portion of the circumferential surface of the shaft102. Hence, according to the example embodiment depicted inFIGS. 3 and 4, the inner ring is integrated in the shaft102. The outer raceway304on the other hand is constituted by a portion of a circumferential inner surface of the gear wheel106. The outer bearing ring is thus integrated in the gear wheel106.

The bearing arrangement104and the gear wheel106are preferably assembled to the shaft102from the left hand side towards the right hand side as illustrated by the assembly direction500. The assembly of the bearing arrangement104and the gear wheel106will be described in further detail below in relation to the description ofFIG. 5.

Furthermore, the shaft102comprises a plurality of lubricating flow channels306. The lubricating flow channels306are arranged to supply lubrication to the bearings105,105′ and extends from a center portion308and radially towards a radially outer end surface310of the shaft102. Thus, the lubricating flow channels306end in an opening312at the radially outer end surface310in the vicinity of the bearing arrangement104. Although not depicted in the figures, the lubricating flow channels may have an extension also in the axial direction thereof such that angled lubricating flow channels are obtained.

Particular reference is now made toFIG. 4in which the ring shaped contact element is depicted in further detail. Firstly, the first ring shaped contact element114will be described. Specifics not described in relation to the first ring shaped contact element114will thereafter be described with reference to the second ring shaped contact element114′.

The ring shaped contact element114comprises a first contact surface402which is facing the end surfaces of the cylindrical roller bearing elements110. Thus, when the bearing arrangement104is exposed to axial loading, the end surface of at least some of the cylindrical roller bearing elements110will abut the first contact surface402of the ring shaped contact element114for transferring the axial loads to e.g. the shaft102. The ring shaped contact element114thus has an extension in the axial direction from the first contact surface402to a second contact surface404arranged in abutment with a radially protruding portion403of the shaft102, or as depicted inFIG. 4, a radially protruding portion of a contact ring116which is connected to the shaft102.

The ring shaped contact element114further comprises a shaft connecting portion408. The shaft connecting portion408is connected to the shaft102, preferably by being press fitted to the shaft102. As can be seen inFIG. 4, the first ring shaped contact element114has an L-shaped form, while the second ring shaped contact element114′ has a straight form. The L-shaped form is suitable at positions where the contact area on the shaft102is arranged at a diameter which is equal to, or smaller than the diameter412of the inner raceway302. The straight ring shaped contact element114′ is thus suitable to use where the contact area on the shaft102is arranged at a diameter which is larger than the diameter412of the inner raceway302. Accordingly, the inner diameter of the shaft connecting portion408may be either equal to, or smaller than the diameter412of the inner raceway302, or larger than the diameter412of the inner raceway302, which is thus dependent on the geometries of the shaft102.

Furthermore, the ring shaped contact element114is positioned relative the inner raceway302in such a way that a continuous radial gap414is formed between the ring shaped contact element114and the inner raceway302. The continuous radial gap414is formed by providing larger diameter410of the ring shaped contact element114at the axial position of the first contact surface402in comparison to the diameter412of the inner raceway302.

By means of the axial extension of the ring shaped contact element114and the radial gap414between the ring shaped contact element114and the inner raceway302, the opening312of the lubricating flow channel306is enclosed and a circumferential distribution channel406is formed. The circumferential distribution channel406extends continuously around the circumference of the inner raceway302for providing a continuous flow of lubrication to the bearing105. The circumferential distribution channel406is also depicted inFIG. 5.

Turning now toFIG. 5which illustrates an exploded perspective view for assembling the bearing arrangement104and the gear wheel106to the shaft102. The bearing arrangement104and the gear wheel106are assembled from the left to the right as seen by the illustrated assembly direction500. Firstly, the second ring shaped contact element114′ is connected to the shaft102at a position located axially to the right of the right most raceway302of the shaft102as seen inFIG. 5. More particularly, the shaft connecting portion408of the second ring shaped contact element114′ is press fitted to the shaft102. The diameter of the second ring shaped contact element114′ at the shaft connecting portion408is preferably larger than the diameter412of the raceway302, and could be equal to the inner diameter410at the first contact surface402.

Thereafter, the second bearing105′ is connected to the shaft102at the right most raceway302of the shaft102. The second bearing105′ is thus arranged to the shaft102such that the first contact surface402of the second ring shaped contact element114′ is positioned in the vicinity of the end surfaces of the cylindrical roller bearing elements110. The gear wheel106is thereafter connected to the shaft102such that the second bearing105′ is enclosed between the shaft102and the gear wheel106. The first bearing105is thereafter positioned between the shaft102and the gear wheel106. Hereby, the first bearing105is positioned at the left most raceway302of the shaft102. When the first bearing105is placed in its position, the first ring shaped contact element114is connected to the shaft102. More particularly, the shaft connecting portion408of the first ring shaped contact element114is press fitted to the shaft102. The diameter of the first ring shaped contact element114at the shaft connecting portion408is preferably equal to, or smaller than the diameter412of the raceway302. The first contact surface402of the first ring shaped contact element114is positioned in the vicinity of the end surfaces of the cylindrical roller bearing elements110.

Finally, the contact ring116is connected to the shaft102such that a portion of the contact ring116is arranged in connection with the second contact surface402of the first ring shaped contact element114.

As further depicted inFIG. 5, when the bearing arrangement104has been assembled to the shaft102, the above described circumferential distribution channel406is formed.