Wheel hub drive

Abstract

A wheel hub drive as a direct drive of a wheel of a vehicle having an electric motor preferably designed as a permanent-magnet synchronous motor (PMSM)—external rotor motor—which is substantially arranged in the region within the wheel, wherein a rotating part of a friction brake is frictionally, interlockingly, and/or integrally connected to the motor for braking. The rotating part is operatively connected to the rotor of the motor, directly or indirectly, from outside of the motor.

Claims

1. A wheel hub drive as a direct drive of a wheel of a vehicle, comprising: an electric external rotor motor as a permanent-magnet synchronous motor (PMSM) which is substantially arranged in the region within the wheel, the external rotor motor having: a rotor attached to an inside surface of a wheel rim, the rotor being configured to rotate with the wheel rim; and a non-rotating stator disposed within an interior of the rotor, wherein operation of the stator induces rotation of the rotor and wheel rim; a friction brake, wherein a rotating part of a friction brake is frictionally, interlockingly, integrally connected to the motor for braking, wherein the rotating part is operatively connected to the rotor of the motor, directly or indirectly, from outside of the motor.

2. The wheel hub drive according to claim 1, wherein the rotating part is directly connected to the rotor of the motor via a flange.

3. The wheel hub drive according to claim 2, wherein a pipe/cylinder extends between the rotating part and the flange, or the flange is a component of a pipe/cylinder.

4. The wheel hub drive according to claim 1, wherein the rotating part is a brake disc of a disc brake system.

5. The wheel hub drive according to claim 1, wherein the rotating part is a brake drum of a drum brake system.

6. The wheel hub drive according to claim 1, wherein a mounting of the rotating part is along a motor axis, corresponding to a width of the rotor at an end or close to the end of the rotor, on a nonrotating stator carrier.

7. The wheel hub drive according to claim 1, wherein an internal converter and optionally other electric/electronic components are integrated into a component-free interior of a stator.

8. The wheel hub drive according to claim 1, wherein the motor includes an electromagnetic motor circuit, and the wheel hub drive further comprises an additional electromagnetic motor circuit, designed as an internal rotor that is housed in a component-free interior of a stator, wherein the two motor circuits are operable by means of one or more external converters.

9. The wheel hub drive according to claim 1, wherein the motor has a removable flange on an outside/wheel-side, and wherein removal of the removable flange makes an interior of the motor, including a converter, electric/electronic systems, or a motor circuit, accessible.

10. The wheel hub drive according to claim 1, wherein the wheel rim is a dual wheel rim for a dual tire.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) In a schematic section drawing, FIG. 1 shows, in part, an exemplary embodiment of a wheel hub drive according to the disclosure having an external rotor motor; and

(2) In a schematic section drawing, FIG. 2 shows, in part, a variant of the wheel hub drive according to the disclosure, in which the mounting is supported, in the interior, on fixed components.

DETAILED DESCRIPTION OF THE DISCLOSURE

(3) In a schematic section drawing, FIG. 1 shows, in part, a wheel hub drive according to the disclosure having an external rotor motor, wherein the wheel hub drive is allocated to a rim 1 for dual tires. The rim 1 is only indicated with its rim well 2 and its connection to the drive.

(4) The wheel hub drive comprises, as substantial components, a rotor 3 connected to the rim 1 in a torsionally-resistant manner, which can be implemented in multiple parts. The stator 4 is arranged within the rotor 3 (external rotor motor) as a nonrotating component. The windings and cooling sleeve 5 of the stator 4 are indicated.

(5) While a shaft connected to a brake disc extends axially through the e-motor in the prior art, a completely different motor design is implemented here, according to which namely the rotating part of the friction brake, in this case the brake disc 6, is connected directly to the rotor 3 from outside of the motor, specifically via a flange 7. The flange 7 may be a separate or integral component. The connection to the rotor may likewise be implemented in any manner, namely frictionally and/or interlockingly and/or integrally connected.

(6) FIG. 2 shows a variant of the wheel hub drive according to the disclosure, in which the mounting (8, 9) is stably supported, in the interior, on fixed components. Contrary to this, FIG. 1 shows a bearing arrangement with a bearing (9) supported so as to rotate on the inner ring. Accordingly, the bearings 8, 9 are positioned, according to FIG. 2, on the exterior, to the extent possible, with consideration of the width of the rotor, and operate between the fixed stator 4 and the rotating rotor 3, which is facing the friction brake on the exterior, allocated to the flange 7 and thus to the rotating part and/or the brake disc 6 of the friction brake.

(7) In light of the general description and the previous description of figures, the advantages and the designs according to the disclosure are summarized as follows again, in contrast to the prior art:

(8) According to the design according to the disclosure, the mounting of rotating inner rings on a shaft is converted to fixed inner rings on a shaft and/or rotating inner rings on a flange. Contrary to a shaft, a flange is characterized by a significantly larger “diameter to length” ratio. To this end, the bearings are shifted to a position as far from the axis as possible, which defines the end of the rotating motor part. This makes it possible to connect the rotating part of the friction brake (brake disc of the disc brake system or brake drum of the drum brake system) to a large rotating flange, directly on the rotor. High braking torques and system-constrained righting moments of the disc brake system are then supported by means of a larger geometry and thus a higher resistance torque. The material strength can then be reduced.

(9) Alternatively, the material used and/or the material thickness can be reduced to achieve a lower weight. This is to be gauged with consideration of the cost, weight, and service life factors.

(10) According to the disclosure, mounting on larger diameters is supported, namely, on the interior on fixed components, instead of on a rotating shaft, according to the prior art. Thus, the arrangement according to the disclosure is more stable. The main mounting is designed to be along the motor axis, according to the width of the rotor. Tilted positions and deformations in the mounted components are greatly reduced due to the geometric form.

(11) The air gap is ensured permanently by means of the modified mounting design and is subject to less fluctuations than in the prior art. The arrangement can thus be more compact, which has a positive effect on the power density and running performance of the e-motor.

(12) Omission of the interior rotating shaft results in a larger hollow interior, which is not penetrated by any problematic geometry. This makes it possible to form an integrated converter in almost any geometric shape and that is thus more economical to produce.

(13) Alternatively or in addition, the existing installation space may accommodate another electromagnetic motor circuit (i.e. winding and magnets, optionally as an internal rotor as well). Both motor circuits can be operated by means of one or more internal and/or external converters.

(14) An internal bearing with clearance fit on the outer diameter up to the stator carrier makes it possible to implement a removable flange on the road-side of the motor, which is favorable for accessing the converter. This greatly reduces the expense for maintenance and replacement. To this end, the rotor must be supported on the stator carrier after removal of the flange. The nominal gap between the rotor and the stator carrier should be designed smaller than the air gap between the rotor magnets and the stator winding. Thus, the flange can be removed without damaging the motor. There should be a lead-in chamfer for the flange on the rotor. Centering of the flange on the rotor should be implemented before centering of the bearing on the stator carrier.

(15) With regard to further advantageous designs of the teaching according to the disclosure, reference is made, to avoid repetition, to the general part of the description and to the attached claims.

(16) Finally, express reference is made regarding the fact that the previously described exemplary embodiments of the teaching according to the disclosure is provided merely for explanation; however, it is not limited to the exemplary embodiments disclosed herein.

LIST OF REFERENCE NUMERALS

(17) 1 Rim, dual rim 2 Rim well 3 Rotor (of the e-motor) 4 Stator (of the e-motor) 5 Windings, cooling sleeve (of the stator) 6 Brake disc (rotating part of the friction brake) 7 Flange (for the connection between the rotating part of the friction brake and the rotor) 8 Bearing, B-side 9 Bearing, A-side