WO2024022562A1

WO2024022562A1 - Steering knuckle-integrated power module

Info

Publication number: WO2024022562A1
Application number: PCT/DE2023/200148
Authority: WO
Inventors: Adrian Messner; Matthias Schulitz
Original assignee: Continental Automotive Technologies GmbH
Priority date: 2022-07-25
Filing date: 2023-07-17
Publication date: 2024-02-01

Abstract

The invention relates to a steering knuckle-integrated power module having a wheel drive, a wheel brake and a wheel bearing function of a motor vehicle, said power module comprising: a steering knuckle (1) having interfaces for attachment to the vehicle; a rotatable wheel bearing (2); a brake assembly (4) acting as a multi-disc brake including a brake actuator (4.1); and a wheel drive motor. The problem addressed by the invention is that of proposing a solution for an improved implementation of drive components and brake components compared to the prior art. In order to solve the problem, according to the invention the brake assembly (4) and the wheel drive motor are positioned integrated on or in the steering knuckle (1).

Description

Steering knuckle-integrated power module

The invention relates to a particularly compact and highly integrated, combined force module, which is intended for generating both driving forces and braking forces in a vehicle, in particular a passenger car (hereinafter referred to as a car for short).

Traditionally, in cars, driving forces are generated in one or more central drive machines and transmitted to individual wheels via drive shafts, whereas braking forces are generated using disc or drum brakes, which are assigned to individual wheels and connected to the respective wheel hubs.

Such traditional arrangements have many disadvantages due to their design. These include, for example, a high overall weight, large space requirements, a large number of wear-prone drive joints, drive losses and inertia due to a long drive train, corrosive consequences of environmental influences on brakes, contamination of the environment by brake dust, etc.

Electric vehicles in particular, and especially autonomous vehicles, for example, tend to have their brakes rust due to the high proportion of regenerative braking.

In order to make the brake more compact, it is known to distribute the required friction surface over several coaxial, axially alternating friction pairs with a reduced outer diameter - so-called multi-disc brakes (hereinafter referred to as MLB for short). For the relevant state of the art, reference is made, for example, to DE 102019208226 B3. Such MLBs have been in use for many years, primarily in agricultural machinery, industrial trucks and other vehicles with reduced requirements in terms of comfort and driving dynamics.

It is also known to integrate braking devices into central drive components such as differential gears, as disclosed in DE 102016214968 A1. From EP 2093450 A1 an MLB is known, which is arranged protected within a separate brake housing, which is screwed to a steering knuckle. However, such an arrangement requires additional mechanical connection and sealing points.

The invention is based on the object of proposing a solution for an implementation of drive and brake components that is improved compared to the prior art. The solution to the problem results from the combination of features of patent claim 1. Advantageous refinements and embodiments of the invention result from the subclaims. In addition, a particularly efficient assembly method is proposed for the first time.

The invention provides, among other things, that an encapsulated solid disc brake, preferably a multi-disc brake (wet or dry) can be combined with a wheel hub motor, and a brake housing of a multi-disc brake (MLB) can be integrated directly into the steering knuckle. Instead of a disassembled assembly of individual parts which takes place in one place, the invention allows for the first time a composite modular construction with integration of all modules on or in the steering knuckle and with improved industrial large-scale series logistics, the modules in question can be prefabricated in a particularly efficient division of labor by certain supplier specialists in order to create a power module, so to speak, downstream made up of prefabricated modules. On the one hand, this makes it possible to reduce the depth of production at a so-called first tier supplier company - which is responsible for the overall assembly - and, on the other hand, it also makes it possible to increase the delivery quality of the component manufacturers involved through an independent functional test of the supplied modules.

In summary, a value chain that is particularly suitable for large-scale production and is presented in a rationalized manner with component production configured in a sensible division of labor. Advantageously, the MLB can be integrated into the wheel bearing unit. This integrative structure leads, in addition to component and mass reduction, in particular to a particularly compact design, which also makes it possible to integrate the power electronics particularly easily into the overall module. Due to the high power density of the MLB (very high braking torques in a compact installation space, due to the large number of friction surfaces), the corner module is also suitable for heavy vehicles (high braking torques) despite its compactness and despite the installation space required for the power electronics. In order to further improve the thermal performance, the cooling system of the brake stator and/or the power electronics, which is usually present anyway, can be combined with the MLB. The cooling system can be used either to cool the brake housing (Fig.4) or a flow cooler through which the oil is pumped (Fig.6). This option for cooling the brake is not possible with known disc or drum brakes and expands the area of application of the module (e.g. pure emergency braking function for people movers to high-performance brakes in luxury vehicles). Another essential advantage of this module is that, compared to the state of the art, there are no emissions caused by brake wear. This is becoming increasingly important, particularly for future vehicles (legal constraints). In addition, the encapsulated design of the MLB does not affect the dirt-sensitive electronics of the wheel hub motor.

Furthermore, the invention increases the thermal performance of the brake, since in the present embodiment no longer just a housing of the MLB, but rather large parts of the steering knuckle are available as thermal mass. The targeted use of passive (e.g. cooling fins) or active (e.g. water cooling) cooling elements offers additional opportunities for improvement.

By integrating the MLB into the steering knuckle, a complex connection point can be saved. In addition to reduced overall costs, the vehicle mass can also be saved in particular. The reduced number of parts leads to a more robust structure and the assembly of the system is simplified. In addition, the MLB can be designed as a service life brake within the module, which is particularly advantageous for fleet management for people movers, for example (long operation time, short workshop time).

Further details of the invention are explained using several exemplary embodiments, some of which are shown in very simplified form.

Axle topologies based on the current state of the art and current distribution on the market in most cases consist of a steering knuckle (1) and a wheel bearing (2) (Fig.1). The brake components (e.g. discs or drum brakes) are connected here in a force-fitting or form-fitting manner.

The multi-disc brake (i.e. MLB) cannot use this interface (or can only use it with a lot of effort) because, due to the system, it has its own storage and an enclosing housing.

The present version (Fig. 2, sections 3 + 4) combines (integrates) the housing of the MLB, here implemented using casting technology, with the steering knuckle (3) and thus offers all interfaces that are crucial for the operation of the brake. The MLB itself can be designed in a variety of ways: hydraulic (shown here (4)) or, for example, fully electric. The task of wheel bearing is taken over by the roller bearings that are already required in the brake (5), which means that the classic wheel bearing set (see FIG. 1) is no longer necessary. The shaft (6) that transmits the braking torque is led in a liquid-tight manner (7) through a housing cover (8) to the outside, where there is a connection to the further wheel topology (e.g. the rim) by means of a flange plate (9). As shown here, this can be implemented, for example, in a form-fitting manner using a shaft-hub connection. An axle screw (10) enables the flange plate to be mounted axially on the shaft.

The design offers great potential especially when the rim installation space is very limited and/or a high degree of component integration is required. This is the case in system networks with wheel-specific drives (e.g. “wheel hub motors”, corner modules). Section 3 shows an example of the present construction with rim contour (11) and the possible stator (12) a wheel hub motor. A classic brake topology is difficult to integrate here, but the present design fits into the installation space.

A brake actuator 4.1 for actuating the MLB within the module can be designed, for example, as a hydraulic annular piston or an electromechanical ball ramp expansion unit.

Fig.5 shows an alternative arrangement between the stator and power electronics compared to Fig.4.

With an active oil circuit (Fig.6), the oil can be pumped out of the brake housing to reduce the residual torque and only pumped into the housing when necessary (e.g. from above). With this setup, the oil can also be pumped through a flow cooler. The cooling system of the stator and/or the power electronics of the wheel hub motor can be used for cooling (synergy effect). This allows the thermal performance of the brake to be significantly increased despite the compact installation space.

In variants without integrated power electronics (Fig.7, electronics are external, i.e. arranged in the vehicle), the additional installation space can be used for a larger, more powerful brake.

An advantageous assembly sequence (Fig. 8), for example, is that the brake assembly is first pre-assembled in the steering knuckle (4) and then the electronics and other parts are assembled.

Further embodiments not explicitly shown here are also conceivable within the invention. For example, a double-sided housing bushing with sealing (2x (element 7)) of the shaft in the steering knuckle geometry and the closing cover (8) can be implemented, for example to enable the connection to an external drive shaft.

Furthermore, if there is a wheel hub motor with an active cooling system, this can also be used to cool the MLB. Reference symbols

1 steering knuckle

2 wheel bearings

3 housing of the multi-plate brake (MLB), integrated into the steering knuckle

4 multi-disc brake/brake assembly

4.1 Brake actuator

4.2 Brake discs

5 rolling bearings

6 wave

7 sealing

8 housing covers

9 flange plate

10 axle screw

11 rim / rim contour

12 stator

13 stator holders

14 cover plate

15 Common cooling circuit of stator and/or power electronics and brake housing

16 rotors

17 Power Electronics

18 axis of rotation

19 screw connection

20 Common cooling circuit between stator and/or power electronics and continuous cooler

21 flow cooler / oil cooler

22 pump

23 oil circuit

24 Common cooling circuit for stator and brake housing

Claims

Patent claims

1. Steering knuckle-integrated power module with wheel drive, wheel brake and wheel bearing function of a motor vehicle, having a steering knuckle (1) with interfaces for vehicle-mounted fixation, having a rotatable wheel bearing (2), having a brake assembly (4) as a full disc brake including brake actuator (4.1), and having a Wheel drive motor, wherein the brake assembly (4) and the wheel drive motor are arranged integrated on or in the steering knuckle (1).

2. Steering knuckle-integrated power module according to claim 1, characterized in that the solid disc brake is designed as a multi-disc brake (MLB).

3. Steering knuckle-integrated power module according to one or more of the preceding claims, characterized in that the solid disc brake is designed to be fully encapsulated.

4. Steering knuckle-integrated power module according to one or more of the preceding claims, characterized in that the solid disc brake is designed to be wet in conjunction with a fluid cooling system (15) or with a dry cooling system.

5. Steering knuckle-integrated power module according to claim 4, characterized in that a fluid cooling system (15; 24) has a coolant-fillable common fluid circuit which is connected on the one hand to the brake assembly (4) and on the other hand to at least one further assembly, such as in particular with the wheel drive motor or its parts and/or with power electronics (17) in the form of a circulation cooling system.

6. Steering knuckle-integrated power module according to claim 4 or 5, characterized in that the steering knuckle (1) is designed as a cooling element of a wet or dry cooling system (15, 24).

7. Steering knuckle-integrated power module according to one or more of the preceding claims 4 - 6, characterized in that a continuous cooler (21) is designed as a cooling element of the fluid cooling system (15, 24).

8. Steering knuckle-integrated power module according to one or more of the preceding claims 4 - 7, characterized in that the fluid cooling system (15, 24) has a motor-driven pump (22).

9. Steering knuckle-integrated power module according to claim 8, characterized in that the pump (22) of the fluid cooling system (15, 24) is driven by an electric motor.

10. Steering knuckle-integrated power module with coolant-fillable, fluid cooling system (15) according to one or more of the preceding claims 5 - 9, characterized in that the fluid cooling system (15, 24), in particular for the purpose of cavity evacuation and fluid coolant filling with pressure, or for the purpose of coolant withdrawal based on negative pressure , has a hermetically sealable filling interface that can be closed with an operational sealing agent and / or an evacuation interface for the fluid coolant.

11. Steering knuckle-integrated power module according to one or more of the preceding claims, characterized in that the solid disc brake, such as in particular the multi-disc brake (MLB), is provided integrated in the wheel bearing (2).

12. Steering knuckle-integrated power module according to one or more of the preceding claims, characterized in that the brake actuator (4.1) is designed to be electrical, hydraulic or electro-hydraulic.

13. Steering knuckle-integrated power module according to one or more of the preceding claims, characterized in that the brake actuator (4.1) has at least one transmission means.

14. Steering knuckle-integrated power module according to claim 13, characterized in that the transmission means of the brake actuator (4.1) is designed as a hydraulic annular piston.

15. Steering knuckle-integrated power module according to claim 13, characterized in that the transmission means of the brake actuator (4.1) is designed as a ramp gear, in particular, for example, as a screw spindle gear.

16. Steering knuckle-integrated force module according to one or more of the preceding claims, characterized in that the brake actuator (4.1) has a ball ramp expansion unit.

17. Steering knuckle-integrated force module according to one or more of the preceding claims, characterized in that the force module is assigned an electric parking brake device.

18. Steering knuckle-integrated power module according to claim 17, characterized in that the electric parking brake device has an electromotive parking brake actuator, which is designed to be self-locking without current.

19. Assembly method for a steering knuckle-integrated power module with wheel drive and with wheel brake, for a motor vehicle, having a steering knuckle (1) with interfaces for vehicle-mounted fixation, having a wheel bearing (2), having a brake assembly (4) including a solid disc brake including brake actuator (4.1), and having a wheel drive motor, in particular according to one or more of the preceding claims, characterized in that in a first assembly step a pre-assembled wheel brake assembly (4) is integrated into the steering knuckle (1) before further assemblies or components, such as in particular power electronics (17 ), a wheel drive motor or other parts or components can be added.