DE102018131958A1 - Brake system with a brake cylinder with several pressure pistons; and electric wheel drive unit - Google Patents

Abstract

The invention relates to a brake system (1) for an electric wheel drive unit (2), with a housing (3) that can be attached to the vehicle frame, a first brake component (4a), the first brake component (4a) being a first support part (4) connected to the housing (3). 5) and a first brake disk element (6) connected to the first support part (5) in a manner fixed against relative rotation, a second brake component (4b) rotatably mounted relative to the housing (3), the second brake component (4b) being a second support part (7) and has a second brake disk element (8), which is non-rotatably connected to the second support part (7) and arranged and designed for frictional connection with the first brake disk element (6), and a hydraulic brake cylinder (9) for applying the brake disk elements (6, 8) to one another connecting braking force, which brake cylinder (9) has a plurality of pressure pistons (1 1) has. The invention also relates to an electric wheel drive unit (2) with this brake system (1).

Description

The invention relates to a brake system for an electric wheel drive unit, in particular a wheel-integrated wheel drive unit (wheel hub drive) for a preferably two, three or four-wheel motor vehicle. Furthermore, the invention relates to an electric wheel drive unit with this brake system.

In the case of electric wheel hub drives, there is in principle a need for the most compact possible integration of the drive components with an appropriate braking system.

It is therefore an object of the present invention to provide a brake system for an electric wheel drive unit which ensures the most compact and robust construction possible.

This is solved according to the invention by the subject matter of claim 1. Accordingly, a brake system for an electric wheel drive unit (also referred to as a wheel hub drive unit) with a housing which can be fixedly attached to the vehicle frame, a first brake component, the first brake component having a first support part connected to the housing and a first brake disc element non-rotatably connected to the first support part, is relative to one second brake component rotatably mounted to the housing, the second brake component having a second support part and a second brake disc element, which is non-rotatably connected to the second support part and arranged and designed for frictional connection with the first brake disc element, and a hydraulic brake cylinder for applying a braking force connecting the brake disc elements to one another Which brake cylinder has a plurality of pressure pistons distributed in the circumferential direction about an axis of rotation of the second brake component.

As a result, a brake system, which is preferably constructed in a dry construction, is implemented, which can be actuated by a multi-piston actuation acting over the entire surface. In particular, this braking system is made compact in the radial direction.

Further advantageous designs are claimed with the subclaims and explained in more detail below.

Accordingly, it is also advantageous if the pressure pistons are connected in a manner fixed against displacement with a common sliding element, which sliding element acts from an axial side on the entirety of brake disc elements. The brake cylinder can thus be arranged in a particularly compact manner relative to the brake disc elements.

For a compact arrangement, it is also expedient if the brake cylinder is arranged radially within the brake disk elements with respect to the axis of rotation and the sliding element penetrates the first support part in the radial direction.

Furthermore, the invention relates to an electric wheel drive unit for an electric vehicle, with a wheel rim, an electric motor arranged within the wheel rim and a brake system according to the invention according to at least one of the embodiments described above, the second brake component being directly or indirectly rotationally coupled to the wheel rim.

In this context, it is particularly expedient if the second brake component is rotationally coupled to the wheel rim indirectly via a gear, particularly preferably a planetary gear.

Furthermore, it is expedient if the electric motor (with its stator and / or rotor) is arranged axially and / or radially offset from the brake system. This results in a compact, powerful wheel drive unit.

In other words, a full-surface multi-piston brake (brake system with several pressure pistons) for an e-wheel application is therefore proposed according to the invention. A multi-piston arrangement extends in the circumferential direction around an axis of rotation.

The invention will now be explained in more detail with reference to figures, in which context various exemplary embodiments are also shown.

• 1 eine Längsschnittdarstellung eines erfindungsgemäßen Bremssystems nach einem bevorzugten Ausführungsbeispiel,
• 2 eine perspektivische Darstellung eines Teils des Bremssystems nach 1, wobei ein Wärmeschutzschild sowie Gehäusebereiche zur Aufnahme mehrerer Druckkolbens eines Bremszylinders gut zu erkennen sind,
• 3 eine perspektivische Darstellung eines ersten Tragteils eines ersten Bremsbestandteils des Bremssystems,
• 4 eine perspektivische Darstellung eines zweiten Tragteils eines zweiten Bremsbestandteils des Bremssystems,
• 5 eine perspektivische Darstellung des Bremssystems nach 1 bei von einem Gehäuse abgenommenen Flanschbereich,
• 6 eine perspektivische Darstellung eines Gehäusebereiches des Bremszylinders mit mehreren Druckkolben,
• 7 eine Längsschnittdarstellung des Bremszylinders im Bereich eines Druckkolbens,
• 8 eine perspektivische Darstellung eines Schiebeelementes des Bremssystems,
• 9 eine perspektivische Darstellung eines ersten Bremsscheibenelementes des Bremssystems,
• 10 eine perspektivische Darstellung eines zweiten Bremsscheibenelementes des Bremssystems, sowie
• 11 eine perspektivische Darstellung einer das Bremssystem nach 1 aufweisenden, in Längsrichtung geschnitten dargestellten Radantriebseinheit, wobei das Bremssystem lediglich schematisch dargestellt ist.

Show it:

• 1 2 shows a longitudinal sectional illustration of a brake system according to the invention in accordance with a preferred exemplary embodiment,
• 2nd a perspective view of part of the brake system according to 1 , where a heat shield and housing areas for receiving several pressure pistons of a brake cylinder are clearly visible,
• 3rd 1 shows a perspective illustration of a first support part of a first brake component of the brake system,
• 4th 2 shows a perspective illustration of a second support part of a second brake component of the brake system,
• 5 a perspective view of the brake system after 1 with flange area removed from a housing,
• 6 1 shows a perspective illustration of a housing area of the brake cylinder with a plurality of pressure pistons,
• 7 2 shows a longitudinal sectional view of the brake cylinder in the area of a pressure piston,
• 8th a perspective view of a sliding element of the braking system,
• 9 1 shows a perspective illustration of a first brake disk element of the brake system,
• 10th a perspective view of a second brake disc element of the brake system, and
• 11 a perspective view of the brake system according to 1 having, shown in the longitudinal direction cut wheel drive unit, the braking system is shown only schematically.

The figures are only schematic in nature and serve only to understand the invention. The same elements are provided with the same reference symbols. In principle, the various exemplary embodiments can also be freely combined with one another.

With regard to the preferred embodiment, in 1 the detailed structure of the braking system according to the invention 1 to recognize. With 11 is also the preferred area of application for this braking system 1 illustrated. The braking system according to the invention 1 is in an electric wheel drive unit 2nd integrated. The wheel drive unit 2nd represents a wheel hub drive unit, both the braking system 1 as well as an electric motor providing the drive 23 inside a wheel rim 22 are arranged for an electric vehicle. The electric motor 23 as well as the braking system 1 are in a common housing 3rd integrated which housing 3rd is typically fixed to the vehicle frame during operation. The wheel rim 22 or one with the wheel rim 22 Wheel hub connected in a rotationally fixed manner is via a central bearing 24th relative to the housing 3rd / the wheel drive unit 2nd stored.

The following axial, radial and circumferential directions refer to a central axis of rotation 10th the wheel rim 22 / a second brake component 4b of the braking system 1 . The axial direction is therefore a direction along the axis of rotation 10th , a direction perpendicular to the axis of rotation under the radial direction 10th and a circumferential direction along a direction concentric about the axis of rotation 10th to understand the circular line running around.

Coming back on 1 is the formation of the housing 3rd of the braking system 1 / the wheel drive unit 2nd in the area of the braking system 1 recognizable in detail. The housing 3rd is the braking system in the description below 1 assigned, but in principle it is also the housing 3rd the wheel hub drive unit 2nd and therefore takes the electric motor in one area 23 (Stator) on. The housing 3rd forms an in 1 recording space to be recognized 25th for the components of the braking system 1 out. The recording room 25th is to a first axial side through a flange area 18th in the form of a lid-shaped flange element of the housing 3rd limited. The receiving space is on its radial inside 25th through a wave-like / peg-like wheel carrier area 26 of the housing 3rd limited. The wheel carrier area 26 is fixed to the flange area 18th connected. The wheel carrier area 26 immediately forms a bearing for the wheel hub. The wheel carrier area 26 is separate from the flange area 18th molded. To a radial outside as well as to the flange area 18th the receiving space facing away from the second axial side 25th by a main housing part extending in the axial direction and in the radial direction 27th limited.

In the recording room 25th is a first brake component 4a fixed to the housing, ie fixed to the housing 3rd , and thus fixed to the vehicle frame during operation. With the first brake component 4a acts the second brake component 4b together, which rotates with the wheel rim during operation 22 is coupled and in a braking state of the wheel drive unit 2nd frictional with the first brake component 4a for braking the wheel rim 22 connected is.

The two brake components 4a , 4b each have a supporting part 5 , 7 and at least one brake disc element 6 , 8th that with the respective support part 5 , 7 is connected to. Accordingly, the first brake component 4a a first supporting part 5 on, also referred to as the inner support / inner disk support and in 3rd is illustrated. This first supporting part 5 is with a mounting area 19th in the axial direction on the flange area 18th created and on the housing 3rd attached. The attachment area 19th is in the axial direction between the flange area 18th and a radially projecting heel 20th of the wheel carrier area 26 fixed. Radially outside the mounting area 19th extends a sleeve area 21st in the axial direction from the fastening area 19th path. The sleeve area 21st is implemented directly as a toothing area and is provided with an external toothing. There are two first ones on the external toothing Brake disc elements 6 rotatably and relatively displaceable in the axial direction. The first brake disc elements 6 accordingly each have a (first) counter toothing to the external toothing 12 on and are positively connected to the first supporting part 5 connected. The first two brake disc elements 6 are essentially lamellar. The first two brake disc elements 6 have a disc-shaped steel body 28 ( 10th ) and one to a second brake disc element 8th of the second brake component 4b arranged friction lining 29 on.

In the axial direction between the first two brake disc elements 6 is the second brake disc element 8th ( 9 ) arranged. The second brake disc element 8th is on a second support part designed as an outer support / outer disk support 7 of the second brake component 4b rotatably, but movable in the axial direction, added. The second supporting part 7 is in 4th also recognizable in detail. The second supporting part 7 has an internal toothing, in which internal toothing the second brake disc element 8th while forming a non-rotatable composite with a (second) counter-toothing on the second brake disc element 8th is inserted.

The second brake component 4b is typically relative to the housing 3rd rotatably mounted. The second brake component 4b is like in 11 schematically recognizable via a planetary gear 30th indirectly with the wheel rim 22 coupled. The planetary gear 30th is also in the case 3rd added. In 1 is a sun gear 31 of the planetary gear 30th to recognize which sun gear 31 firmly with the second support part 7 connected is.

In this context it should also be noted that a different number of brake disc elements 6 or. 8th is predictable.

According to the invention is now according to 1 a hydraulic brake cylinder 9 to operate the brake system 1 , ie for frictionally connecting the first and second brake components 4a , 4b illustrated with each other. The hydraulic brake cylinder 9 points as in 2nd Also recognizable is a plurality of housing areas, here two distributed in the circumferential direction 17th on. The housing areas 17th are radially within the sleeve area 21st arranged. In every housing area 17th are three pressure pistons 11 axially displaceable, as in 6 also easy to recognize. Every pressure piston 11 forms a pressure chamber 13 with the housing area 17th out ( 7 ). The pressure piston 11 again includes one from the housing area 17th protruding body 14 , one with the body 14 connected press-in cone 15 and one between base body 14 and press-in cone 15 recorded seal 16 . The seal 16 also has a reinforcement 32 on. The three one housing area 17th assigned pressure piston 11 are outside the housing area 17th together with a distribution sheet 33 non-displaceably connected. The pressure pistons 11 serve to apply a braking force to the entirety of the first and second brake disc elements 6 , 8th in a braking process. For this purpose, the pressure pistons 11 over the distribution sheet 33 with a sliding element 12 coupled, which sliding element 12 on a (first) brake disc element arranged at the end 6 from the entirety of the brake disc elements 6 , 8th is in plant. On one of the sliding elements 12 opposite side is a counter pressure plate 34 again directly on the first support part 5 trained to provide a corresponding counterforce for the braking force.

The sliding element 12 penetrates, as if the 1 , 5 and 8th to recognize the first supporting part 5 in the radial direction. So the brake cylinder 9 with its housing areas 17th and its pressure piston 11 in the radial direction within the first and second brake disc elements 6 , 8th arranged, the sliding element 12 radially from the brake cylinder 9 to the brake disc elements 6 , 8th extends.

In order to enable heat dissipation during operation, the brake disc elements are in the 6 , 8th components of the braking system which surround radially from the outside 1 each have radial / radial through holes 35 (also called openings / windows) implemented. Several in the second supporting part 7 through holes 35 are in 4th to recognize. Accordingly, there are in a sleeve region of the second support part which forms the internal toothing 7 a plurality of through holes arranged distributed in the circumferential direction 35 intended. Also in one the brake disc elements 6 , 8th in the radial direction from the outside surrounding heat shield 36 that is firmly attached to the housing 3rd such through holes are included 35 , here in the form of rectangular windows, implemented ( 2nd ). As can also be seen, there are also circular through holes 35 in that first heat shield 36 available. Furthermore, are in the housing 3rd , namely the main housing part 27th , a plurality of through holes are provided in a peripheral region. This enables air circulation and heat dissipation in the radial direction to the outside during operation.

In other words, according to the invention, a multi-disc brake (braking system 1 with brake components 4a , 4b) implemented in dry construction, which by a Multi-piston actuation is actuated. Generally a design with a disc (brake disc element 6 , 8th ) or with several discs / slats possible.

The outer disk carrier / brake disc driver (second supporting part 7 ) is directly in the sun 31 flange-mounted on the planet carrier. Moments are transmitted via a form fit. In the area of the brake discs / brake discs 8th is an external toothing (radially outside the brake plates / brake discs 8th arranged internal teeth) attached, the moments on the slats 8th transmits. In this toothing there are also recesses (through holes 35 ) are provided, which serve to dissipate heat. An air exchange can thus take place, which is caused by the rotary movement of the disk carrier 7 is favored. The brake disc (second brake disc element 8th ) is shown here in a most ideal variant rotating. For this, their external toothing (second counter toothing 16 ) in the brake disc driver 7 a. Around the pane 8th two slats are to be braked (first brake disc elements 6 ) on both sides of the disc 8th attached to brake pads 29 are completed. Both slats 6 are via an internal toothing (first counter toothing) in a further plate carrier (first supporting part 5 ) supported. This inner disc carrier 5 is on the fixed wheel flange 18th attached, causing braking of the disc 8th against a standing component. This carrier 5 can be supported, for example, on the bolts of the wheel suspension, as in 5 shown. This also offers slat carriers 5 a stop collar (counter pressure plate 34 ), so that there is a flow of force within the stationary components when the brake 1 is operated. The complete slat package 6 , 8th will be against the wreath 34 depressed when the brake 1 is operated.

To operate the brake 1 is a hydraulic multi-piston system (brake cylinder 9 with several pressure pistons 11 ) attached, which via a pressure pot (sliding element 12 ) on the plate pack 6 , 8th presses. There are six pistons in the figures 11 shown, however, the number of pistons 11 can be varied freely; any number is generally conceivable. The actuators 11 are in one housing 17th introduced and consist essentially of a seal 16 and a piston (basic body 14 ). The components reinforcement 32 and press-in cone 15 are additional and serve to extend the life of the seal 16 or the assembly lock. The three pistons 11 per side of the wheel carrier 26 are over a sheet 33 connected. This sheet 33 again presses when the pistons are actuated 11 on the pressure pot 12 . This pressure pot 12 fits through the inner disk carrier 5 through and forms in the inner area the complementary surface to the sheet 33 out. The whole can be done with a support plate 37 are stiffened, and thus also connected the two piston systems. Ideally, the system has a reset element 38 . In this case there is a disc spring for this 38 provided on the wheel carrier 26 supports and via a circlip 39 is positioned. That feather 38 makes sure the brake 1 is released again and again after there is no more actuation pressure on the cylinder 9 is present. In 3rd you can also use the inner disk carrier 5 and the complementary recesses to the pressure pot 12 detect. A heat shield 36 is attached outside the actual brake. As a feature, it can be stated that single and multiple disc concepts are conceivable, as well as rotating or standing pads and or steel masses.

Reference symbol list

1

Braking system

2nd

Wheel drive unit

3rd

casing

4a

first brake component

4b

second brake component

5

first supporting part

6

first brake disc element

7

second supporting part

8th

second brake disc element

9

Brake cylinder

10th

Axis of rotation

11

Pressure piston

12

Sliding element

13

Pressure room

14

Basic body

15

Press-in cone

16

poetry

17th

Housing area

18th

Flange area

19th

Fastening area

20th

paragraph

21st

Sleeve area

22

Wheel rim

23

Electric motor

24th

camp

25th

Recording room

26

Wheel carrier area

27th

Main housing part

28

Steel body

29

Friction lining

30th

Planetary gear

31

Sun gear

32

reinforcement

33

Distribution sheet

34

Pressure plate

35

Through hole

36

Thermal shield

37

Gusset

38

Reset element

39

Circlip

Claims (4)

Brake system (1) for an electric wheel drive unit (2), with a housing (3) which can be fixedly attached to the vehicle frame, a first brake component (4a), the first brake component (4a) being a first support part (5) connected to the housing (3) and a Has a first brake disk element (6) connected in a rotationally fixed manner to the first support part (5), a second brake component (4b) which is rotatably mounted relative to the housing (3), the second brake component (4b) being a second support part (7) and a non-rotatably connected to the second supporting part (7) connected, arranged and formed for the frictional connection with the first brake disc element (6), second brake disc element (8), and a hydraulic brake cylinder (9) for applying a brake force connecting the brake disc elements (6, 8) to each other, which Brake cylinder (9) has a plurality of pressure pistons (11) distributed in the circumferential direction about an axis of rotation (10) of the second brake component (4b). Brake system (1) after Claim 1 , characterized in that the pressure pistons (11) are connected to a common sliding element (12), which sliding element (12) acts from an axial side on the entirety of brake disc elements (6, 8). Brake system (1) after Claim 2 , characterized in that the brake cylinder (9) is arranged radially within the brake disc elements (6, 8) with respect to the axis of rotation (10) and the sliding element (12) penetrates the first support part (5) in the radial direction. Electric wheel drive unit (2) for an electric vehicle, with a wheel rim (22), an electric motor (23) arranged within the wheel rim (22) and a brake system (1) according to one of the Claims 1 to 3rd , wherein the second brake component (4b) is directly or indirectly rotationally coupled to the wheel rim (22).

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