Drive device for a vehicle

Abstract

The invention relates to a drive device for an electrically powered vehicle (1), comprising an electric motor (30) and a brake (10), wherein the brake (10) and the electric motor (10) are provided as a unit (4) for acting on a wheel connection (2) of the vehicle (1), and wherein the brake (10) is designed as a wet multi-disc brake.

Description

[0001] The invention relates to a drive device for a vehicle. The drive device comprises an electric motor and a brake, wherein the brake is provided as a unit for acting on a wheel connection.

[0002] Drive devices are known. These devices can, for example, accelerate, decelerate, and / or recuperate energy from a wheel. A disadvantage of these drive devices is that significant effort is required to repair or replace components that wear out or become defective.

[0003] As examples of the state of the art, reference should be made to CN 1 11 503 252 A and DE 298 20 349 U1, which each disclose drive devices with electric motor and brake.

[0004] The invention aims to provide a drive device that is improved in terms of performance and maintenance requirements. In particular, a more cost-effective solution is to be provided. Specifically, the disadvantages of the prior art are to be avoided or at least reduced.

[0005] The problem is solved by the features of the independent claims. Preferred embodiments are specified in the dependent claims and in the description, each of which, individually or in combination, can represent an aspect of the invention.

[0006] A drive device for an electrically powered vehicle is proposed, the drive device comprising an electric motor and a brake, wherein the brake and the electric motor are provided as a unit to act on a wheel connection of the vehicle, and wherein the brake is designed as a wet multi-disc brake.

[0007] In other words, an arrangement for a hybrid or electric vehicle is proposed. The arrangement comprises at least one electric machine or electric motor and a deceleration device or brake, which are operatively connected to, or can be operatively connected to, a wheel connection on the vehicle. The deceleration device includes a wet, for example, oil-cooled, multi-disc brake.

[0008] The invention recognizes that wheel-integrated, dry disc brakes, for example with a floating caliper, are particularly disadvantageous. Internal disc brakes, which are located outside a transmission on the typically two output shafts of a vehicle, are also disadvantageous. The proposed brake is intended to replace such disc brakes or perform essentially the same function. In this respect, a dry brake can be dispensed with. Fine dust emissions are avoided. Fluctuations in the coefficient of friction due to environmental influences, such as moisture, do not occur. Corrosion due to environmental influences is also prevented when a wet multi-disc brake is used. Furthermore, noise levels are reduced in increasingly electrified vehicles with small or no combustion engines, where the noise of a dry brake would otherwise be prominent.

[0009] A key aspect of the invention is therefore to replace the dry disc brake with an oil-cooled or wet multi-disc brake and integrate it into the transmission or the electric drive axle. This is intended to reduce wear and prevent emissions into the environment by binding the resulting abrasion particles in a fluid, usually cooling oil. Furthermore, the proposed brake is no longer exposed to environmental influences within the e-axle or the drive unit, which further extends its service life. Noise generation is also significantly reduced or eliminated due to the integration into the e-axle and the use of oil as a lubricant in the friction contact. Additionally, the brake can be arranged within the e-axle in a simplified manner, allowing for easy replacement during servicing.

[0010] A unit is understood to be, in particular, an assembly. In this respect, the brake and electric motor are preferably connected to one another, for example, via a common housing or via interconnected housings or frames of the brake and electric motor. A unit is characterized, for example, by the fact that the components are arranged directly next to each other and / or coaxially. A unit can form an individually manageable, structurally essentially stable, assembly. In this respect, the unit according to the invention differs from classic arrangements of an electric motor acting on the wheel connection and a brake acting on the wheel connection, which do not form a unit, in that the brake and electric motor are separate. The brake is usually found in the wheel housing, for example as a disc brake with a floating caliper, while the electric motor is located away from it (i.e.,(It is not directly adjacent to and not coaxially coupled to a drive shaft.) Therefore, the electric motor and brake do not form a single assembly and cannot be individually controlled together while maintaining a structurally stable unit. Rather, they are separate units.

[0011] In particular, the invention realizes the concept of combining two classically separate units—namely, the brake unit and the drive unit—into a single unit comprising both the brake and the motor. The brake is advantageously further developed as a wet multi-disc brake. This is particularly beneficial when the brake is located close to the motor, which, in the case of electric motors, can have a permanent connection to the wheel in many vehicles. This saves installation space. In this respect, the conventional dry wheel brake can be replaced by the inventive solution, even achieving improved performance.

[0012] According to the invention, the brake is arranged on the side of the electric motor facing the wheel connection. Furthermore, the brake is arranged at least partially coaxially with a rotor shaft of the electric motor. With this arrangement, the brake is close to the wheel connection and can lead to particularly good response characteristics and a reliable drivetrain design. The interaction between the electric motor and the brake is also improved. In particular, the brake is connected to the wheel connection in such a way that the wheel of the connection can always be decelerated. In this respect, the brake is particularly advantageous for being ready for use at all times.

[0013] A gearbox coupling the brake and the electric motor may be provided. For example, a reduction or acceleration of the electric motor's speed may be provided. The gearbox ratio may be adjustable or fixed. An inner plate carrier may be attached to a rotating gear element of the gearbox. The inner plate carrier may be rotatable. In particular, the gearbox may be designed as a planetary gear system. The gear element may have a connection section for a side shaft of the wheel connection. The wheel can be driven or braked via the side shaft. The connection section may have internal teeth, particularly to create a permanently rotationally fixed connection that can also be disconnected if necessary.

[0014] It is advantageous if the electric motor is designed as a radial flux machine, particularly with an internal or external rotor, or as an axial flux machine, particularly with an I- or H-rotor. This is especially true in combination with a planetary gearbox, in order to create a particularly space-saving and efficient drive device.

[0015] It may be possible to house the brake and the electric motor together in a single housing. In this respect, the brake and electric motor can be enclosed together. The housing may have an opening for accessing the brake. This opening allows, in particular, the replacement of the brake's friction plates. The opening may be designed to be closable, for example, to allow for brake maintenance and / or the replacement of brake components. In particular, the opening is provided on the side facing the wheel mounting, so that, for example, the brake can also be serviced when the wheel is removed.

[0016] A connector section may be provided through which coolant and / or oil can be routed into the housing and / or the brake. The connector section may be a port, a fitting, or the like. The coolant or oil can be changed as needed via the connector section.

[0017] The brake can be designed as a subassembly comprising an outer plate carrier, a plate pack, and an actuating element that acts on the plate pack. The outer plate carrier can be connected to the actuating element via a plug connection. The plate pack can be arranged between the actuating element and the outer plate carrier. The plug connection can be secured by a retaining ring. A preferred embodiment of the brake comprises, as a subassembly, the outer plate carrier, which is connected to the actuating element via the plug connection, and the plate pack arranged between the two elements. Preferably, the plug connection is positively secured by a retaining ring.

[0018] In particular, at least one of the following can be provided: an outer lamella carrier, a lamella pack, and an actuating element, preferably two or all of which are provided. The actuating element is specifically designed to act on the lamella pack. The actuating element can be spring-loaded. In a preferred embodiment, a braking torque can be transmitted from the inner lamella carrier via the lamella pack to the outer lamella carrier. In particular, during actuation or braking, a braking torque can be transmitted from a rotating inner lamella carrier via the lamella pack to the outer lamella carrier. Preferably, the outer lamella carrier is supported against an actuating force from the actuating element. In particular, a support section arranged opposite the actuating element is provided for this purpose.The outer lamella carrier can be supported against rotation in the housing, for example by means of a positive locking mechanism, in particular by means of a splined connection.

[0019] Preferably, the lamellar assembly comprises at least one, and preferably a plurality, for example two, three, four, five, six or more, friction pairs. The lamellar assembly preferably has axially movable friction discs and intermediate discs arranged alternately (at least one of each, preferably several). The friction disc(s) is / are, for example, rotationally fixed to one or more of the rotor shaft or the lamellar carrier, and the intermediate disc(s) is / are fixed to the other component. When the wheel or rotor shaft rotates, the friction disc(s) and the intermediate disc(s) move relative to each other. When the lamellar assembly is subjected to tension, this relative movement results in friction within the lamellar assembly, thus producing braking. A friction pair preferably forms at least a substantially ring-shaped contact.

[0020] The actuating element may be arranged between the electric motor and a gear element and / or adjacent to the electric motor. A pressure element or pressure piece may be provided through which the actuating element can act on the lamellar assembly. The pressure piece may be equipped with return springs to effect a return movement.

[0021] Furthermore, a vehicle, in particular an electrically powered vehicle, for example a hybrid vehicle or a fully electric vehicle, is proposed, with at least one of the drive devices, preferably two or more drive devices, for driving one or more wheels of the vehicle.

[0022] It is further proposed to use a wet multi-disc brake in a drive unit for an electrically powered vehicle. The drive unit comprises an electric motor and the brake, with the brake and the electric motor acting as a single unit on a wheel connection of the vehicle. In this respect, the features of the drive unit described herein can (at least partially) also be preferably applied and advantageously combined in the context of use. The idea is to use a wet multi-disc brake in an electric or hybrid vehicle, for example, as a service brake. In particular, this eliminates the need for a drum and / or disc brake and / or a brake running coaxially to the wheel of the vehicle.

[0023] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination. The drawings show: Fig. 1 a drive device in a half section, Fig. 2 a brake of a drive device in a half section, Fig. 3 a brake of a drive device in a half section, Fig. 4 a brake of a drive device in a front view, and Fig. 5 a drive device in a half section.

[0024] If the same reference symbols are used in the figures, the following description applies accordingly to the figures among themselves.

[0025] The invention is illustrated here by the example of a performance e-axle with two electric motors 30, i.e., one electric motor 30 per wheel connection 2 or per wheel. Application to an e-axle with a single electric motor 30 is also possible. In this case, the brake 10 must be positioned at the output shaft, as with the performance e-axle.

[0026] Fig. Figure 1 shows a drive device for an electrically powered vehicle 1, comprising an electric motor 30 and a brake 10, wherein the brake 10 and the electric motor 30 are designed as a unit 4 for acting on a wheel connection 2 of the vehicle 1. The brake 10 is a wet or oil-cooled multi-disc brake, comprising an inner disc carrier 12, an outer disc carrier 14, and a disc pack 16. The brake 10 and the electric motor 30 are housed together in a casing 5. The casing 5 has an opening 26 for accessing the brake 10.

[0027] The lamellar assembly 16 has five friction pairs. Each friction pair forms a substantially ring-shaped contact. Each friction pair is located between a friction disc and an intermediate disc. In this case, friction discs are rotationally fixed to one of the lamellar carriers 12 or 14, and the intermediate discs are rotationally fixed to the other lamellar carrier 12 or 14, respectively. In particular, a plurality of friction pairs is provided.

[0028] The performance e-axle has a separate drive for each of the two wheels or their respective wheel connections. Each drive consists of an electric motor 30 and a gearbox 40 and is arranged in Fig. Figure 1 shows that a differential is not strictly necessary here, as no speed differences occur between the drive and the respective wheel during cornering. The electric motors 30 can be designed as either radial flux machines (internal or external rotor) or axial flux machines (I- or H-rotor). The possible variants resulting from the integration of the brake 10 can initially be divided into three categories depending on the arrangement of the axis of rotation of the electric motor 30 and the axis of rotation of the wheels. The system can be designed coaxially, parallel to the axis, or with crossed axes. For good accessibility, it is usually necessary to arrange the brake 10 at the output of the electric axle. The side shafts 3, which connect the electric axle to the wheels, are also attached here. This arrangement also ensures that the brake 10 can always be directly connected to the wheels (e.g., without a chain or gearbox).

[0029] A coaxial design of the e-axle is particularly advantageous with regard to the number of components, the assembly and the accessibility of the brake 10, wherein the two electric motors 30 are arranged in the center of the vehicle (inside) and the gearbox 40 and the brake 10 follow in the direction or on the side of the wheels (outside) on both sides 32.

[0030] A torque from the electric motor 30 is transmitted via a rotor shaft 34 to the gearbox 40, more precisely to planetary gears 47 of the gearbox 40, which is designed as a planetary gearbox. The planetary gears 47 are in contact with the rotor shaft 34 (as a sun) and with a ring gear 46 (typically internally toothed). The output is via the planet carrier 48, which is mounted in the housing 5 and on the rotor shaft 34. The inner plate carrier 12 of the brake 10 is attached to the planet carrier 48. The planet carrier 48 also has an output hub 50 with a connecting section 44 with internal teeth to establish a rotationally fixed contact with the side shaft 3. Thus, the electric motor 30 and the brake 10 are connected to the side shaft 3 via the planet carrier 48. In this case, the planet carrier 48 functions as a rotating transmission element 42 of the gearbox 40.

[0031] In particular, the brake 10 is arranged between the electric motor 30 and the wheel connection 2. In other words, the brake 10 is arranged, for example, on a side 32 facing the wheel connection 2 on the electric motor 30 and coaxially to the rotor shaft 34.

[0032] The brake 10 is arranged as an assembly next to the gearbox 40. It is secured by the cover 24, which seals an opening 26, or the E-axle, in the direction of the wheels. The brake 10 is supplied with actuating and cooling oil from the outside via screwed-on connector sections 6. These are installed externally, for example, after the brake 10 has been mounted.

[0033] With reference to Fig. Figure 2 shows the brake 10 as an assembly. This includes an actuating piston as actuating element 18 with its housing 19, an outer plate carrier 14, a pressure piece with return springs as pressure element 22, and a plate pack 16. A braking torque is transmitted from the inner plate carrier (not shown here) via the plate pack 16 to the outer plate carrier 14. The outer plate carrier 14 is proposed to be supported against rotation in a housing of an e-axle, e.g., by a splined connection.

[0034] One advantage of this design is a closed force flow between the housing 19 of the actuating element 18 and the lamellar carrier 14, which supports the actuating force at the other end of the lamellar pack 16. The two parts 14 and 19 are connected to each other via a plug connection 28, specifically with a retaining ring. This eliminates the need to support actuating forces on the housing of the e-axle. This allows the assembly to be pre-tested before installation in the e-axle, reducing the effort required for rework during e-axle assembly. The assembly of the e-axle is also simpler and faster due to the brake assembly process. Furthermore, the design is easily scalable.

[0035] In Fig. Figure 3 shows a further sectional view of the drive device, showing that cooling oil, such as actuating oil, can be introduced from the outside into a housing 19 of an actuating element 18 via a connector section 6 and directed into a lamellar carrier 14 in the lower half (relative to the axis of rotation D). The lamellar carrier 14 distributes the oil via its rotational movement, allowing the oil to cool and absorb wear particles.

[0036] When the vehicle or the respective wheel is stationary (inner fin carrier no longer rotates), the brake 10 can be cooled externally. For this purpose, cooling elements are provided on the upper side of the outer fin carrier 14. Fig. 3 holes are provided.

[0037] In Fig. Figure 4 shows that a cooling oil outlet 29 is arranged on the underside (approximately at the 8 o'clock position) of the drive device. Furthermore, several, in particular three, tabs are provided distributed around the circumference, by means of which the brake 10 can be axially positioned in a housing of an electric motor.

[0038] In Fig. Figure 5 shows a further embodiment of the drive device. To reduce the overall length of the e-axle (in the transverse direction of the vehicle or parallel to the axle), it is possible to arrange the actuating device (here CSC) between the electric motor 30 and the respective transmission 40 or planetary gear set. In this respect, an actuating element 18 is located elsewhere opposite Fig.1. For actuation, it is proposed to use a pressure pot 23, in particular a two-part one, to enable a connection between an actuating piston, as the actuating element 18, and a clutch pack 16 of the brake 10. The actuating element 18 engages through a ring gear 46 of the planetary gear. The actuating mechanism is supported on the opposite side of the clutch pack 16. A support element, designated as a support section 20, can be provided. The support section 20, like a cover 24, can be easily removed to allow replacement of the clutch pack 16 during servicing.

[0039] In this embodiment, the lamellar assembly 16 is arranged directly in a housing 5 in order to transmit a torque or braking torque to the housing 5. In particular, no external lamellar carrier is provided. Reference symbol list 1 vehicle 2-wheel connection 3 Side shaft 4 units 5 cases 6 Connector section 10 Brake 12 internal slat carriers 14 outer slat carriers 16 slat package 18 Actuating element 19" enclosure 20 Support section 22 Pressure element 23 Pressure pot 24 lids 26 Opening 28 retaining ring 29 Cooling oil leak 30 electric motor Page 32 34 Rotor shaft 40 gearboxes 42 Gear element 44 Connection section 46 Ring gear 47 Planet 48 planetary carriers 50 Output hub

Claims

[1] Drive device for an electrically powered vehicle (1), comprising an electric motor (30) and a brake (10), wherein the brake (10) and the electric motor (10) are provided as a unit (4) for acting on a wheel connection (2) of the vehicle (1), and wherein the brake (10) is designed as a wet multi-disc brake, characterized by , that the brake (10) is arranged on a side (32) facing the wheel connection on the electric motor (30) and is arranged coaxially to a rotor shaft (34) of the electric motor (30). [2] Drive device according to one of the preceding claims, comprising a transmission (40) coupling the brake (10) and the electric motor (30). [3] Drive device according to claim 2, wherein the transmission (40) is designed as a planetary transmission and / or the electric motor (30) is designed as a radial flux machine or as an axial flux machine. [4] Drive device according to one of claims 2 or 3, wherein the transmission element (42) has a connection section (44) for a side shaft (3) of the wheel connection (2). [5] Drive device according to one of the preceding claims, wherein the brake (10) and the electric motor (30) are together housed in a housing (5), wherein the housing (5) has an opening (26) for access to the brake (10) and for replacement of one or more of the lamellar packs (16) of the brake (10), in particular on one or more of the side (32) facing the wheel connection. [6] Drive device according to one of the preceding claims, comprising connector section (6) through which a coolant and / or oil can be conveyed into the housing (5) and / or the brake (10). [7] Drive device according to one of the preceding claims, wherein the brake (10) is designed as a sub-assembly with an outer lamella carrier (14), the lamella pack (16) and an actuating element (18) acting on the lamella pack (16), the outer lamella carrier (14) is connected to the actuating element (18) via a plug connection, and the lamella pack (16) is arranged between the actuating element (18) and the outer lamella carrier (14). [8] Drive device according to one of claims 1 to 6, comprising an outer lamella carrier (14), a lamella pack (16) and an actuating element (18) acting on the lamella pack (16). [9] Drive device according to claim 7 or 8, wherein the actuating element (18) is arranged between the electric motor (30) and a / the transmission element (42) and / or adjacent to the electric motor (30).

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