DRIVEN FAN FOR VEHICLE WHEEL BRAKE

Abstract

The invention relates to a fan for a wheel brake of a vehicle, the fan comprising: a coupling portion for coupling the fan to the vehicle; a blade assembly that is rotatable relative to said coupling portion to generate an air flow; and a drive unit for rotating the blade assembly. Also, a method of operating such a fan is disclosed.

Claims

1. A fan for a wheel brake of a vehicle, the fan comprising: a coupling portion for coupling the fan to the vehicle; a blade assembly that is rotatable relative to said coupling portion to generate an air flow; and a drive unit for rotating the blade assembly.

2. The fan according to claim 1, characterized in that said drive unit is adapted to drive said blade assembly at a rotational speed that is different from a rotational speed of at least one of: wheel or a wheel hub of the vehicle, which are coupled to the wheel brake; and a rotatable component of the wheel brake, in particular a brake disc.

3. The fan according to claim 1, characterized in that the drive unit is configured to drive the blade assembly for generating an air flow by means of which brake noises of the wheel brake can at least partially be dampened.

4. The fan according to claim 1, characterized in that the drive unit is selectively activatable for generating the rotation, the selective activation depending on at least one operating parameter of the vehicle.

5. The fan according to claim 4, characterized in that the operating parameter is one of the following: an activation state of the wheel brake; a movement parameter of the vehicle, in particular a vehicle speed or a vehicle acceleration.

6. The fan according to claim 1, characterized in that the wheel brake comprises a brake disc and a vehicle wheel coupled to the wheel brake comprises a rim, wherein the blade assembly is arrangeable between the brake disc and the rim.

7. The fan according to claim 6, characterized in that the coupling portion is couplable to an inner side of the rim or to the brake disc.

8. The fan according to claim 1, characterized in that the blade assembly is configured to change between a first configuration, in which the blade arrangement has a first radial extension, and a second configuration in which the blade assembly has a second radial extension, the first and second radial extensions being different.

9. The fan according to claim 1 characterized in that the fan is adapted to collect brake dust emitted by the wheel brake.

10. A vehicle wheel arrangement, comprising: a vehicle wheel; a wheel brake; and a fan according to claim 1

11. A method of operating a fan for a wheel brake of a vehicle, wherein the fan comprises a blade assembly for generating an air flow, the method comprising: generating a rotation of the blade assembly relative to at least one of: a wheel or wheel hub of the vehicle coupled to the wheel brake; and a rotatable component of the wheel brake, in particular a brake disc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The invention will be explained further with reference to the figures in which same features are marked with same reference signs.

[0047] FIG. 1 is a cross-sectional view of a vehicle wheel arrangement comprising a fan according to a first embodiment.

[0048] FIG. 2 is a cross-sectional view of a vehicle wheel arrangement comprising a fan according to a second embodiment.

[0049] FIG. 3 is a view of a fan according to a third embodiment when assuming a radially collapsed configuration.

[0050] FIG. 4 is a view of the fan according to the third embodiment when assuming a radially extended configuration.

DETAILED DESCRIPTION

[0051] Hereinafter, the present disclosure will be described with reference to the accompanying drawings presented as described above.

[0052] In the cross-sectional view of FIG. 1, a rim 10 of a vehicle wheel arrangement 12 and a wheel brake 14 of said vehicle wheel arrangement 12 are depicted. The wheel brake 14 is a disc brake. It comprises a brake disc 16 and a floating caliper 18 as well as further components, such as brake pads, which are not illustrated.

[0053] The rim 10 and the wheel brake 14 can have generally known configurations. Accordingly, they contact each other by way of an axially extending center portion 20′ of the wheel brake 14 contacting an inner side of the rim 10. In a generally known manner, bolts (not illustrated) may be inserted through through-holes (not illustrated) extending through the rim 10 and center portion 20′ to connect these components to a wheel hub. A position of the not illustrated wheel hub is indicated with reference sign 13 (reference sign 11 indicates a wheel of the vehicle).

[0054] In FIGS. 1 and 2, the wheel arrangements 12 are only partially depicted. Specifically, only an upper part with respect to a rotational axis R of the rim 10 and brake disc 16 are depicted. Said components 10, 16 are preferably rotationally symmetric with respect to the rotational axis R. Any references to axial and radial directions refer to said rotational axis R with radial directions extending orthogonally thereto.

[0055] Referring to FIG. 1, a fan 20 is shown which is positioned in a space between an inner side of the rim 10 and an outer side of the brake disc 16. The terms “inner” and “outer” refer to an orientation of the wheel arrangement 12 at and with respect to a vehicle. In FIG. 1, a left side of the rim 10 faces outward and a left end of the rotational axis R points outward, whereas a right side of the brake disc 16 (as well as a right end of the rotational axis R) faces inward.

[0056] The fan 20 comprises a coupling portion 22. By way of example, this coupling portion 22 is configured as a sleeve-like member that is pushed onto an axially and inwardly protruding portion 24 of the rim 10. Accordingly, an inner circumferential face of the coupling portion 22 contacts an outer circumferential face of the rim 10, and in the example shown of the respective portion 24 of the rim 10.

[0057] The connection between the coupling portion 22 and the rim 10 preferably includes an additional mechanical fixation between these components, e.g. by means of screws. Generally, the coupling portion 22 is non-rotatable relative to the rim 10 but rotates jointly therewith.

[0058] It is to be noted that in FIG. 1 (but also in FIG. 2) the fan 20 is configured rotationally symmetric with respect to the rotational axis R.

[0059] The fan 20 of FIG. 1 further comprises a blade assembly 26, one blade 28 of which is visible in FIG. 1. Preferably, at least three or four blades 28 are provided and are positioned at equal angular or circumferential distances to each other.

[0060] The blade assembly 26 is connected to the coupling portion 22 by a drive unit 30 of the fan 20. Merely as an example, the drive unit 30 is configured as a ring-shaped member that connects an outer circumferential face of the coupling portion 22 to the blades 28 of the blade assembly 26.

[0061] In the example shown, the drive unit 30 comprises an electric motor. The electric motor preferably has an inner stator-outer rotor configuration, with the stator preferably being fixed to the coupling portion 22 and the rotor preferably being fixed to the blades 28.

[0062] The drive unit 30 is configured to rotate the blades 28 about the rotational axis R. A rotational speed of the blades 28 can be set to be different from a rotational speed of the rim 10 and brake disc 16. That is, the blades 28 can rotate relative to the rim 10 and wheel brake 14. This may be referred to as rotating the fan 20 independently of a rotation of the wheel brake arrangement 12. Put another way, at least a part of the rotational speed of the fan 20 is generated independently of a rotational speed of the rim 10 and wheel brake 14 by means of the drive unit 30.

[0063] In the example shown, the blades 28 are rotated to generate an air flow A that is directed inwardly, and thus towards the brake disc 16 and away from the rim 10. Further, the rotational speed of the blades 28 is set to generate an air flow A of sufficient strength to achieve a desired noise cancellation effect of brake squeal, and in particular of dominant acoustic frequencies associated with an expected brake squeal. The relation between the needed strength of the air flow A (and thus the rotational speed of the blades 28) for achieving a desired noise cancellation effect can be determined by way of experiment or simulation.

[0064] The drive unit 30 comprises a controller (not illustrated). By way of slip rings (not illustrated), data signals can be transferred from a data bus of the vehicle to data lines attached to the rim 10 (not illustrated) and connected to the controller of the drive unit 30. Similarly, electric energy can be transferred to the drive unit 30 by way of such a slip ring and such electric lines (not illustrated).

[0065] The controller of the drive unit 30 selectively activates the drive unit to rotate the blades 28 when receiving a respective activation signal through the above-discussed data connection. Alternatively, the controller may determine that an activation condition is fulfilled based on other data received by said data connection, e.g. data on operating parameters of the vehicle. These may indicate, for example, an activation of the wheel brake 14 and/or that a negative vehicle acceleration exceeds a defined threshold.

[0066] As additional advantageous effects, the—preferably only selectively generated—air flow A (that is, selectively generated when the wheel brake 14 is activated) also provides a cooling effect for the brake disc 16. Further, brake dust can be prevented from being expelled outwardly into the surroundings. For example, the blades 28 or an outer surface of the brake disc 16 may at least partially be coated with an adhesive to which the brake dust adheres.

[0067] FIG. 2 shows an alternative configuration of the fan 20, the remaining components of the wheel arrangement 12 being unchanged from FIG. 1. Again, the fan 20 comprises a radially extending blade assembly 26, one blade 28 of which is visible in FIG. 2. Further, a drive unit 30 that is similarly operable to the drive unit 30 of FIG. 1 connects the blades 28 to a coupling portion 22.

[0068] In contrast to the embodiment of FIG. 1, the coupling portion 22 is coupled and preferably mechanically fixed to the disc brake 16. Specifically, an inner circumferential face of the again ring- or sleeve-like coupling portion 22 is connected to an outer circumferential face of the axially protruding center portion 20′ of the brake disc 16 (also referred to as a brake hat in the technical field). Again, providing data signals and electric power to the drive unit 30 can be accomplished by way of slip rings (not illustrated).

[0069] In FIGS. 3 and 4, different configurations of a fan 20 are shown. The fan 20 can be used in any of the embodiments of FIGS. 1 and 2, but also independently thereof.

[0070] The fan 20 is depicted with the rotational axis R extending towards the viewer (i.e., orthogonally to the image plane). Merely as a simplification, the drive unit 30 and the connecting portion 22 are illustrated as a joint ring-shaped member. Four blades 28 are distributed along an outer circumferential surface of the drive unit 30. The blades 28 assume a collapsed or radially retracted configuration in FIG. 3. In order to be able to do so they each comprise a rotatable joint 34. The rotatable joints 34 each comprise an electric motor, thus forming actuators for folding and unfolding the blades 28.

[0071] Specifically, in order to change between the depicted collapsed configuration and a non-collapsed configuration, the joints 34 can rotate a radially outer portion of the blades 28 in a circumferential direction. This is exemplified for one radially outer portion 29 in FIG. 3 by a respective arrow C. When rotated so as to assume the non-collapsed state, the blades 28 may have a substantially linear unfolded shape.

[0072] In FIG. 4, the respective blades 28 are depicted in their non-collapsed configuration. It is evident that their radial extension is increased with respect to the folded configuration of FIG. 3. Merely as a simplification, the rotational joints 34 are not depicted in FIG. 4. Further, compared to FIG. 3 an area of the blades 28 that faces the viewer is enlarged. This can be achieved when additionally rotating the blades 28 about an axis B indicated for one of the blades 28 in FIG. 4. However, this is a merely optional feature. The invention may be configured in such a way that the folding and unfolding by means of the rotational joints 34 of FIG. 3 represents the only possibility to change a configuration of the blades 28 with respect to their extent and/or orientation.

[0073] Extending the blades 28 from their radially collapsed configuration takes place when activating the wheel brake 14 and in preparation of activating the drive unit 30. Thus, when the fan 20 is not driven to be rotated, it assumes the collapsed configuration. This helps to reduce drag and provides a compact—and thus preferred—appearance of the fan 20.