Patent Application
20240246358
The present invention relates to a locking assembly for securing a wheel rim to a wheel hub of a vehicle, a wheel attachment system, and a method for attaching a wheel rim to a wheel hub of a vehicle.
A wheel of a vehicle, typically, is attached to a wheel hub by securing a wheel rim to the hub by means of a plurality of screws. Other solutions for attaching the wheel rim to the wheel hub employ a single central locking screw that secures the wheel rim on the hub. In this case, usually, measures are taken to secure the locking screw in a locking position in order to avoid unintended loosening of the locking screw.
For example, US 2013/0020855 A1 discloses a device for securing a wheel nut of a central lock on a wheel hub. The wheel hub is provided with an external thread to which the wheel nut is screwed. The device is designed as a securing cover comprising a shaft with an external thread and a cylindrical flange region extending radially from an end of the shaft. The securing cover, with the external thread of the shaft, can be screwed into the internal thread of the hub so that cylindrical flange region radially overlaps the wheel nut.
One of the ideas of the present invention is to provide improved solutions for attaching a wheel rim to a hub, e.g. at one central fixing point.
To this end, present invention provides a locking assembly for securing a wheel rim to a wheel hub of a vehicle in accordance with claim 1, a wheel attachment system in accordance with claim 11, and a method for attaching a wheel rim to a wheel hub of a vehicle in accordance with claim 13.
According to a first aspect of the invention, a locking assembly for securing a wheel rim to a wheel hub of a vehicle comprises a locking screw and a safety screw. The locking screw includes a sleeve body that has an external thread for engaging with an internal thread of the wheel hub and an internal thread, a flange or collar formed at a first end of the sleeve body for abutment against the wheel rim with respect to an axial direction, and a plurality of clamping jaws formed at a second end of the sleeve body and arranged spaced to each other along a circumference of the sleeve body, each jaw being elastically deformable in a radial direction and having a radially inner surface and a radially outer surface for contacting a contact surface of the wheel hub. The safety screw includes a shaft that has an external thread for engaging with the internal thread of the sleeve body of the locking screw, and a head provided at a first end of the shaft, the head having a radially outer surface for contacting the radially inner surfaces of the jaws. At least one of the radially inner surfaces of the jaws and the radially outer surface of the head of the safety screw is conical, so that the jaws are spread outwards in the radial direction, when the shaft of the safety screw with its external thread is screwed into the internal thread of the sleeve body of the locking screw.
According to a second aspect of the invention, a wheel attachment system includes a wheel hub comprising a central hub, which has an outer circumferential surface for receiving a wheel rim thereon and an inner circumferential surface provided with an internal thread, and a collar protruding radially from the outer circumferential surface of the central hub, and a locking assembly according to the first aspect of the invention. The inner circumferential surface of the central hub has a portion arranged distanced to the internal thread that forms a contact surface of the wheel hub. The locking screw, with the external thread of the sleeve body, is screwable or configured to be screwed into the internal thread of the central hub so that the clamping jaws are in frictional contact with the contact surface of the wheel hub. The safety screw, with the external thread of the shaft, is screwable or configured to be screwed into the internal thread of the sleeve body of the locking screw so that the clamping jaws are spread radially outwards against the contact surface of the wheel hub to generate a predefined clamping force between the clamping jaws and the contact surface of the wheel hub.
According to a third aspect of the invention, a method for attaching a wheel rim to a wheel hub of a vehicle is provided. The method, for example, may be carried out by means of the wheel attachment system of the second aspect of the invention. The method includes positioning the wheel rim on an outer circumferential surface of a central hub of the wheel hub such that the central hub protrudes through a receiving opening of the wheel rim. In a further step, a locking screw is screwed into an inner thread provided on an inner surface of the central hub, wherein the wheel rim is clamped between a flange of the locking screw and a collar radially protruding from the outer circumferential surface of the central hub, and wherein a plurality of clamping jaws provided on an axial end of the locking screw come into frictional contact with a contact surface of the wheel hub, said contact surface being formed by a portion of the inner circumferential surface of the central hub distanced to the internal thread. The method further includes screwing a safety screw into an internal thread of the locking screw, wherein a head of the safety screw are moved into contact with radially inner surfaces of the jaws, and the jaws are spread outwards in the radial direction to generate a clamping force between the clamping jaws and the contact surface of the wheel hub.
One of the ideas on which the present invention is based is to secure a locking screw at a wheel hub, on the one hand, by means of engaging an external thread of the locking screw with an internal thread of the wheel hub and, on the other hand, by means of clamping jaws that are radially pushed against an inner circumferential surface of the wheel hub by a head of a safety screw that is screwed into an internal thread of the locking screw. Thereby, a radial clamping force is generated that urges the clamping jaws against the inner circumferential surface or contact surface of the wheel hub. Thereby, at least a friction fit and, preferably, also a form fit between the jaws and the wheel hub is achieved that prevents rotation of the locking screw.
The locking screw has a sleeve body, e.g. a hollow, substantially cylindrical body that defines a screw longitudinal axis. An axial direction is parallel to the screw longitudinal axis. A radial direction extends transverse to the screw longitudinal axis.
The jaws are formed integrally with the sleeve body and positioned at one end of the sleeve bod with respect to the axial direction. For example, each jaw may include a clamping body that includes the radially inner and outer surfaces, and an elastically deformable web that connects the clamping body and the sleeve body. For example, the web may have a smaller thickness in the radial direction than the clamping body. An outer diameter defined by the radially outer surfaces of the clamping jaws may be greater than an inner diameter defined by the contact surface of the wheel hub, so that a preloaded frictional contact occurs already when the locking screw, with its external thread, is screwed into the internal tread of the wheel hub. The safety screw has a shaft with the outer thread and a head. An outer circumferential surface of the head of the safety screw and/or the radially inner surfaces of the jaws may be ramp shaped or conical so that, when the outer circumferential surface of the head of the safety screw and the radially inner surfaces of the jaws are in contact and the head is moved in the axial direction towards an end of the sleeve body opposite of the end where the jaws are formed, the head spreads or moves the jaws outwards in the radial direction.
One of the advantages of the invention is that the jaws provide a very efficient and reliable interlocking between the wheel hub and the locking screw. Since the jaws are radially spreadable by axially moving the safety screw, i.e. by screwing the safety screw into the internal thread of the locking screw, a radially compact solution is provided. Further, the frictional or clamping force between the jaws and the wheel hub generated by the head of the safety screw help to increase self-locking properties of the threaded connection between the wheel hub and the locking screw and the threaded connection between the locking screw and the safety screw.
Advantageous embodiments of the present disclosure are provided in the dependent claims and in the following description, referring to the drawings.
According to some embodiments, an outer diameter defined by the radially outer surfaces of the clamping jaws is greater than an inner diameter defined by the contact surface of the wheel hub. Since the jaws are elastically deformable, the jaws are pre-tensioned against the contact surface even when the safety screw is not engaged with the locking screw.
According to some embodiments, the radially outer surfaces of the clamping jaws and the contact surface of the wheel hub are conical, wherein a greatest outer diameter defined by the radially outer surfaces of the clamping jaws is greater than a smallest inner diameter defined by the contact surface of the wheel hub. Thus, the jaws and the contact surface engage in a form fitting matter with respect to the axial direction when the locking screw is screwed into the internal thread of the central hub, even without the safety screw being introduced. Further, when the safety screw is screwed into the internal thread of the locking screw, the head of the safety screw not only urges the jaws into further contact with the contact surface but also blocks radial movement of the jaws and, thereby, secures the jaws in their form fitting position.
According to some embodiments, the flange of the locking screw includes a tool interface configured to engage with a tool for rotating the locking screw. For example, the tool interface may be provided at an axial end face of the flange that faces away from the sleeve body. Thereby, the radial dimensions of the locking assembly may be further reduced. Further, actuation of the locking screw is eased further.
According to some embodiments, the tool interface includes a plurality of pockets formed at an axial end face of the flange. For example, the pockets may be positioned spaced to each other along a circumference of the flange or collar. In some examples, at least two pockets may be provided. The pockets serve to receive engagement pins of the tool in order to apply a rotational moment to the flange by means of the tool.
According to some embodiments, the external thread and the internal thread of the sleeve body of the locking screw are counter-rotating. Thus, when viewing along the screw longitudinal axis from the side of the flange of the locking screw, both, the locking screw and the safety screw can be rotated in the same direction to move them axially in opposite directions. For example, the locking screw can be rotated clockwise in order to introduce the locking screw into the wheel hub, i.e. the central hub, and the safety screw, when seen from the side of the flange of the locking screw can be rotated clockwise, too, in order to introduce the safety screw into the sleeve body of the locking screw and spread the clamping jaws radially outward. Thus, a simple fixing procedure can be realized. Further, unintended loosening of the safety screw and of the locking screw can be further prevented.
According to some embodiments, the external thread of the sleeve body of the locking screw is a trapezoidal thread.
According to some embodiments, the internal thread of the sleeve body of the locking screw is an ISO metric screw thread.
According to some embodiments, the shaft of the safety screw is formed as a hollow shaft. Optionally, the outer thread of the safety screw is arranged in a predefined axial distance to the head. Thereby, an elastic expansion zone is advantageously formed.
According to some embodiments, the safety screw includes a tool interface configured to engage with a tool for rotating the safety screw, wherein the tool interface is formed at a second end of the shaft. For example, when the shaft of the safety screw is formed as a hollow shaft, the tool interface may comprise engagement structures formed on the inner circumferential surface of the shaft. For example, the inner circumferential surface of the shaft, at the second end, may define a hexagon or another polygonal shape. Hence, the locking screw and the may be actuated from the same side which further eases the assembly process of the locking assembly on the wheel hub.
According to some embodiments, the flange of the locking screw includes a central opening forming a passage into the sleeve body. Thereby, for example, access to the optional tool interface of the safety screw is further eased.
According to some embodiments, the safety screw, with its external thread, is screwable into the internal thread of the sleeve body of the locking screw to a locking position in which the jaws are spread outwards in the radial direction and in which the shaft of the safety screw protrudes into the central opening of the locking screw by a predefined length. For example, the second end of the shaft of the safety screw, with regard to the axial direction, may be positioned in a predefined distance to the axial end face of the flange or collar. Hence, it is simply visible through the opening of the flange when the safety screw assumes the locking position. Thereby, correct and complete attachment of the safety screw can easily be checked. Further, if the flange or collar of the locking screw is provided with the optional tool interface, the tool for rotating the locking screw may be provided with a guide part that protrudes into the central opening of the flange. Thus, when the safety screw assumes the locking position, engagement of the tool with the tool interface may be prevented. Thereby, unintended loosening of the locking screw can efficiently be prevented.
According to some embodiments, the locking assembly may comprise a cover including a cover plate for abutment against a surface of the flange and a pillar protruding from the plate, the pillar having a first engagement structure formed thereon in a predefined axial distance of the cover plate, wherein the shaft of the safety screw includes a second engagement structure formed complementary to the first engagement structure of the cover, and wherein the axial distance is dimensioned such that the first and the second engagement structures are engageable only when the cover plate abuts the surface of the flange and the safety screw is in the locking position. The first and second engagement structures may, for example, be formed as complementary clips and recesses. By dimensioning the axial distance in accordance with the position of the engagement structure of the safety screw when the safety screw is in the locking position, a further possibility of checking the correct positioning of the safety screw is provided.
The features described herein for one aspect of the invention are also disclosed for the other aspects of the invention and vice versa.
For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings. The invention is explained in more detail below using exemplary embodiments, which are specified in the schematic figures of the drawings, in which:
In the figures like reference signs denote like elements unless stated otherwise.
As exemplarily shown in
As shown in
As visible best in
The flange 14 optionally may also include a central opening 14C that forms a passage into the interior space of the sleeve body 10, as visible in
As shown in
The plurality of clamping jaws 16 are realized as members that at least partially are elastically deformable. For example, each clamping jaw 16 may include a clamping body 16D and an elastically deformable web or connection body 16C that has a smaller thickness than the clamping body 16D, as shown in
As visible best in
The safety screw 2, as exemplarily shown in
As shown in
The external thread 21 of the safety screw 2 is formed on an outer circumferential surface of the shaft 20 and configured for being engaged with or screwed into the internal thread 12 of the locking screw 1, as shown in
The head 22 of the safety screw 2 is formed on the first end 20A of the shaft 20 and may, for example, be formed as a substantially circular collar protruding in the second screw radial direction from the outer circumferential surface of the shaft 20, as exemplarily shown in
The optional tool interface 25 is configured to engage with a tool (not shown) for rotating the safety screw 2 and is formed at a second end 20B of the shaft 20. As exemplarily shown in
As visible further in
The locking assembly 100 shown in
As shown in
The collar 215, as shown in
As shown in
In order to rigidly attach the locking screw 1 to the wheel hub 200, the locking screw 1, with the external thread 11 of the sleeve body 10, is further screwed into the internal thread 210 of the wheel hub 200 until the radially outer surfaces 16b of the jaws 16, with respect to the longitudinal or axial direction A100 partially or fully overlap with the contact surface 216a of the wheel hub 200, as shown in
As shown in
As shown in
In step M2, the locking screw 1 is threadingly engaged with or screwed into the inner thread 210 of the central hub 205, so that the wheel rim 300 is clamped between the flange 14 of the locking screw 1 the collar 215 of the wheel hub 200. Moreover, by screwing the locking screw 1 into the inner thread 210 of the central hub 205 in step M2, the clamping jaws 16, i.e. the radially outer surfaces 16a of the jaws 16 come into frictional contact with the contact surface 216a of the wheel hub 210. During step M2, the safety screw 2, for example, may already be engaged with the locking screw 1 via the external thread 21 of the safety screw 2 and the internal thread 12 of the locking screw 1, as shown in
In step M3, the safety screw 2 is further screwed into the internal thread 12 of the locking screw 1, e.g. until it assumes the locking position. That is, in step M2, the head 22 of the safety screw 2 is moved into contact with the radially inner surfaces 16a of the jaws 16, and the jaws 16 are spread outwards in the radial direction R) to generate a clamping force between the clamping jaws 16 and the contact surface 216a of the wheel hub 200. For example, a clamping force of at least 80 KN may be achieved.
Before engaging the locking screw 1 with the wheel hub 200 and the safety screw 2 with the locking screw, the threads 11, 12, 21 may be treated with a lubricant.
The locking screw 1 and/or the safety screw 2, generally, may be manufacture from steel, aluminum, or a similar metal material. Optionally, the surfaces of the locking screw 1 and/or the safety screw 2 may be coated with a chemical nickel coating. Generally, the surfaces of the locking screw 1 and/or the safety screw 2 may have a surface hardness of at least 680 HV.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of at least ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.
