Brake device for an electric axle drive device and electric axle drive device with a brake device

Abstract

The invention relates to a braking device (1) for an electric axle drive device comprising: - a displacement device (2) for displacing a connecting device (3) of the brake device (1), by means of which the brake device (1) can be frictionally connected to a vehicle wheel or to a transmission device of an electric axle drive device in order to slow down a vehicle wheel or the transmission device, - wherein the displacement device (2) comprises at least one piston unit (14) with the aid of which a connecting device (3) of the brake device (1) can be displaced, and - a supply device (4) for supplying the displacement device (2) with a pressurizable fluid, - wherein the supply device (4) has a fluid guidance unit (5) which guides a pressurizable fluid to the at least one piston unit (14) so ​​that the at least one piston unit (14) can be supplied with a pressurizable fluid, - wherein the fluid guidance unit (5) comprises a fluid guidance channel (6) and an inlet (7), and - wherein the fluid guide channel (6) is designed as a groove and connects the inlet (7) to the at least one piston unit (14) in a fluid-communicating manner. Furthermore, the invention relates to an electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle.

Description

[0001] The invention relates to a braking device for an electric axle drive device and an electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle.

[0002] From DE 10 2019 201 989 A1 an electric axle drive device is known which, in addition to a transmission for converting the torque of an electric machine, has a braking device (cf. Fig. 2 of DE 10 2019 201 989 A1).

[0003] The braking device 30 can reduce the speed of the electric machine 12. For this purpose, a second axially movable pressure plate 36 is actuated via a ring actuator 52, which can position the second axially movable pressure plate 36 against a braking element 32 of the braking device 30. From the other side of the braking element 32, a first pressure plate 34, which is stationary in the housing 10, can be actuated.

[0004] In such a braking device, supplying the ring actuator with pressurized fluid is a complex solution. This is because the pressurized fluid is typically fed to the ring actuator via one or more drilled supply channels to move its piston. These drilled supply channels must be connected to each other and then partially sealed, as no pressurized fluid should escape at the entry point of the drill. The entry point is purely a manufacturing requirement to ensure optimally routed supply channels. This manufacturing method is cost-intensive.

[0005] As a result, a corresponding material depth is required to produce bores. This, in turn, increases the weight. A braking device according to the preamble of claim 1 is known from DE 200 14 539 U1. Further prior art is disclosed in FR 1 135 583 A.

[0006] Therefore, it is an object of the present invention to provide a braking device for an electric axle drive device and an electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle, which can be produced simply and thus cost-effectively and in a material-saving manner in order to reduce weight and to save energy.

[0007] This problem is solved by the features of the independent patent claims. Further advantageous developments are the subject of the dependent claims.

[0008] A first aspect of the present invention includes a braking device for an electric axle drive device.

[0009] The braking device comprises a displacement device for displacing a connecting device of the braking device, with the aid of which the braking device can be non-positively connected to a vehicle wheel or to a transmission device of an electric axle drive device. Thus, a vehicle wheel or the transmission device can be slowed down. The connecting device can non-positively connect the braking device, which can be arranged fixedly in a housing of an electric axle drive device, to a rotating part of an electric axle drive device, such as a vehicle wheel or to a rotating subcomponent of a transmission device of the electric axle drive device. In this way, a vehicle wheel or the rotating subcomponent can be slowed down.

[0010] The displacement device comprises at least one piston unit, with the aid of which a connecting device of the braking device can be displaced.

[0011] Furthermore, the braking device has a supply device for supplying the displacement device with a pressurizable fluid.

[0012] The supply device comprises a fluid guide unit that guides a pressurizable fluid to the at least one piston unit, so that the at least one piston unit can be supplied with a pressurizable fluid. This allows a piston of the at least one piston unit to be moved or displaced.

[0013] The fluid guide unit comprises a fluid guide channel and an inlet, wherein the fluid guide channel is designed as a groove and fluidly connects the inlet to the at least one piston unit. A groove offers the advantage of being simple, cost-effective, and material-saving.

[0014] In this description, the term groove is given the meaning commonly used in technical terminology, namely a groove is to be understood as an elongated depression in a component, introduced into a surface of the component.

[0015] A groove can have a rectangular cross-section or a trapezoidal shape, with a tapered wall, or be a dovetail. Furthermore, a groove can be machined, for example, with a milling machine.

[0016] The supply device, e.g. its fluid guide unit and / or its closure unit, can be made of a metal such as aluminum or steel.

[0017] Furthermore, the fluid guide channel can follow the course of the supply device. Furthermore, the fluid guide channel can have a curved and / or an annular course.

[0018] The supply device also comprises a closure unit arranged on the fluid guide unit to close the fluid guide channel. Thus, for example, the fluid guide unit, which can be provided with a fluid guide channel configured as a groove, can be easily closed, so that the fluid guide channel of the fluid guide unit can carry a pressurizable fluid.

[0019] The closure unit may comprise at least one seal to fluid-tightly close the fluid guide channel at the transition to the fluid guide unit. The at least one seal may be arranged within at least one sealing groove of the closure unit.

[0020] The closure unit and the fluid guide unit can be fastened to each other, e.g. by means of screws.

[0021] The supply device can be designed as a circular disc.

[0022] The closure unit and the fluid guide unit can be designed as a circular disc.

[0023] Furthermore, the fluid guide unit or the closure unit for the at least one piston unit of the displacement device can comprise at least one supply channel which fluidly connects the fluid guide channel to a pressure chamber of the at least one piston unit.

[0024] The at least one supply channel can be designed as a bore that penetrates the fluid guide unit or the closure unit completely or from a first side to a second side of the fluid guide unit or the closure unit. Thus, the at least one supply channel can be manufactured quickly, easily, and precisely.

[0025] Furthermore, the fluid guide unit or the closure unit can comprise at least one seal to fluid-tightly close the at least one supply channel at the transition to the at least one piston unit. The at least one seal can be arranged within a sealing groove of the fluid guide unit or the closure unit.

[0026] The fluid guide unit also has a first and a second side. The at least one piston unit of the displacement device is arranged on the first side. The second side can include the fluid guide channel. Furthermore, a sealing groove for each seal of the fluid guide unit can also be arranged on the first side. Furthermore, the closure unit is arranged on the second side.

[0027] In addition, the fluid guide unit or the closure unit may comprise an outlet for heat dissipation of a pressurizable fluid.

[0028] The inlet and / or outlet can be formed by means of at least one bore.

[0029] Furthermore, the inlet and / or outlet can be formed by two bores that intersect each other, e.g. at a vertical angle.

[0030] The inlet and / or outlet may also have a connection opening to which the braking device can be connected to a fluid supply system.

[0031] The part or area of ​​the fluid guide unit or the closure unit with the inlet and / or outlet can have a greater material thickness than the part or area of ​​the fluid guide unit with the fluid guide channel.

[0032] The inlet and / or outlet can further be connected to the fluid guide channel in a fluid-communicating manner, so that pressurizable fluid can flow into the supply device through the inlet and, after flowing through the fluid guide channel, can flow out through the outlet.

[0033] Furthermore, the at least one piston unit can comprise a housing and a piston displaceable therein. The housing can comprise a cylindrical cavity in which the piston can be displaced. A pressure chamber can be formed between the piston and the housing. The piston can be moved from a retracted state to an extended state and vice versa, with the pressure chamber having a larger volume in the extended state than in the retracted state. Furthermore, the housing can be attached to the supply device or to its fluid guide unit, e.g., by means of screws.

[0034] The piston may comprise a piston element for contacting the connecting device of the braking device. The piston element may have a seal for sealing the pressure chamber and / or a sliding band for improved movability or displacement of the piston relative to the housing or within the housing.

[0035] Furthermore, the piston can comprise a guide element. The pressure chamber can be formed between the guide element and the housing. The guide element serves to improve the guidance of the piston within the housing or within the cylindrical cavity of the housing, as well as to simplify its insertion into the cavity.

[0036] The piston element and the guide element can be fastened to each other, e.g. by means of a screw.

[0037] The at least one piston unit may comprise a bellows which is attached to the piston or to its piston element and the housing in order to prevent the penetration of unwanted fluids or particles between the housing and the piston.

[0038] The displacement device can, for example, comprise at least one spring holder per piston unit, which can be connected, e.g., screwed, to a housing of the at least one piston unit. A bellows of the at least one piston unit can be clamped between the at least one spring holder and a housing of the at least one piston unit.

[0039] The displacement device can, for example, comprise at least one spring plate and at least one return element per piston unit, both of which are movable relative to at least one spring holder of the displacement device.

[0040] The at least one spring plate and the at least one return element can be rigidly connected to one another, e.g., by means of screws. The at least one return element can contact a piston of the at least one piston unit, for example, its piston element, in order to return the piston from an extended state to a retracted state.

[0041] In addition, the displacement device can comprise, for example, at least one spring element per piston unit, which is arranged between at least one spring plate of the displacement device and at least one spring holder of the displacement device in order to return at least one return element of the displacement device to its initial position. In the initial position, the displacement device exerts no or only a very small force on the connecting device, so that the connecting device cannot force-fit the braking device to a vehicle wheel or to a transmission device of an electric axle drive device in order to decelerate a vehicle wheel or the transmission device.

[0042] The displacement device can comprise a plurality of piston units or at least two piston units which are evenly distributed along the spatial course of the connecting device in order to displace the connecting device evenly and without tilting.

[0043] Furthermore, the connecting device can comprise a pressure distribution unit that evenly distributes the applied pressure, generated by the displacement of the at least one piston unit, along the spatial extent of the pressure distribution unit. The pressure distribution unit can have a shape similar to a hollow cylinder or a shape similar to an annular disk. The pressure distribution unit can also comprise a receiving area for the arrangement of disc elements in order to realize a non-rotating or rotationally fixed part of a multi-disk brake.

[0044] A second aspect of the present invention includes an electric axle drive device.

[0045] It is expressly pointed out that the features of the braking device as mentioned under the first aspect can be used individually or in combination with one another in the electric axle drive device.

[0046] In other words, the features relating to the braking device mentioned above under the first aspect of the invention can also be combined with further features here under the second aspect of the invention.

[0047] An electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle comprises a braking device according to the first aspect.

[0048] Furthermore, the axle drive device may comprise an electric machine and a transmission device connected to the electric machine, wherein the transmission device is connectable to one or more vehicle wheels.

[0049] The electric machine and / or the transmission device may comprise multi-disk elements to realize a rotating part of a multi-disk brake.

[0050] The braking device with its connecting device and the transmission device and / or the electric machine can be operatively connected so that a ring gear or a planet carrier or a sun gear or a shaft or a gear of the transmission device and / or the electric machine can be slowed down.

[0051] In the following, the inventive concept presented above is expressed again and additionally in other words.

[0052] In simplified form, this idea relates to a braking device for an electric axle drive device with a fluid guide channel which is formed on the one hand by a groove in a fluid guide unit and which is closed on the other hand by a closure unit, so that the fluid guide channel can be designed to be fluid-tight.

[0053] In other words, a housing part of the braking device or a housing of at least one piston unit of a displacement device of the braking device, which ensures the fluid supply to at least one piston unit of a displacement device of the braking device, can be manufactured simply and thus cost-effectively and with reduced material consumption. At the same time, this allows a reduced weight of the braking device to be achieved, thus saving energy.

[0054] Furthermore, at least one piston unit of a displacement device of the braking device, in which a pressure chamber can be formed, can be manufactured, for example, as an extruded profile in a very material-saving and cost-saving manner.

[0055] The invention is explained in more detail below using an exemplary embodiment in conjunction with the accompanying drawings. The drawings schematically show: Fig. 1A and Fig. 1B shows a spatial front and rear view of a braking device for an electric axle drive device; Fig. 2 a plan view of the front and a sectional view along BB; Fig. 3 an enlarged sectional view of an area from Fig. 2; Fig. 4 a spatial representation of the braking device from Fig. 1A with a cut along AA from Fig. 2 and; Fig. 5 a sectional view along CC from Fig. 2.

[0056] In the following description, the same reference symbols are used for the same items.

[0057] Fig. 1A and Fig. 1B show a spatial front and rear view of a braking device 1 for an electric axle drive device.

[0058] Fig. Figure 2 shows a plan view of the front and a sectional view along BB, where Fig. 3 an enlarged sectional view of an area from Fig. 2 represents.

[0059] In Fig. Figure 4 is a three-dimensional view of the braking device 1 with a section along AA from Fig. 2 and in Fig. 5 a sectional view along CC from Fig. 2 shown.

[0060] Below are the Fig. 1A to 5 are described together for the sake of brevity and simplicity. Reference is made to figures in which the features described below are particularly well illustrated.

[0061] This is how the Fig. 1A to 5 a braking device 1 for an electric axle drive device.

[0062] The braking device 1 has according to Fig. 3 and Fig. 5 a displacement device 2 for displacing a connecting device 3 of the braking device 1, with the aid of which the braking device 1 can be non-positively connected to a vehicle wheel or to a transmission device of an electric axle drive device in order to slow down a vehicle wheel or the transmission device. The connecting device 3 can non-positively connect the braking device 1, which can be arranged fixedly in a housing of an electric axle drive device, to a rotating part of an electric axle drive device, such as a vehicle wheel or to a rotating subcomponent of a transmission device of the electric axle drive device. In this way, a vehicle wheel or the rotating subcomponent can be slowed down.

[0063] The displacement device 2 has six piston units 14 (cf. Fig. 1A, Fig. 1B, Fig. 2), with the aid of which a connecting device 3 of the braking device 1 can be displaced.

[0064] Furthermore, the figures show that the braking device 1 comprises a supply device 4 for supplying the displacement device 2 with a pressurizable fluid.

[0065] According to Fig. 3, the supply device 4 comprises a fluid guide unit 5, which guides a pressurizable fluid to the piston units 14, so that the piston units 14 can be supplied with a pressurizable fluid. This allows a piston 16 of each piston unit 14 to be moved.

[0066] The fluid guide unit 5 has a fluid guide channel 6 and an inlet 7, wherein the fluid guide channel 6 is designed as a groove and connects the inlet 7 with each piston unit 14 in a fluid-communicating manner (cf. Fig. 3 and Fig. 4).

[0067] As in the Fig. 1A to 5 and how especially in Fig. 4, the fluid guide channel 6 follows the course of the supply device 4, wherein the fluid guide channel 6 has a curved course or a circular course.

[0068] Furthermore, Fig. 3 and Fig. 5, that the supply device 4 has a closure unit 8 which is arranged on the fluid guide unit 5 in order to close the fluid guide channel 6.

[0069] The locking unit 8 has two seals 9, 10 (cf. Fig. 3, Fig. 4 and Fig. 5) in order to seal the fluid guide channel 6 at the transition to the fluid guide unit 5 in a fluid-tight manner.

[0070] Each seal 9, 10 is arranged within a sealing groove of the closure unit 8 (cf. Fig. 3 to 5), wherein the closure unit 8 and the fluid guide unit 5 are fastened to each other by means of screws (cf. Fig. 1A, Fig. 1B and Fig. 5).

[0071] Furthermore, all figures show that the supply device 4 is designed as a circular disk. In other words, the closure unit 8 and the fluid guide unit 5 are designed as circular disks.

[0072] As in Fig. 3, the fluid guide unit 5 has a supply channel 11 for each piston unit 14 of the displacement device 2, which fluidly connects the fluid guide channel 6 with a pressure chamber D of the piston unit 14.

[0073] The supply channel 11 is designed as a bore which penetrates the fluid guide unit 5 completely or from a first side S1 to a second side S2 of the fluid guide unit 5.

[0074] According to Fig. 3 and Fig. 5, the fluid guide unit 5 has several seals 12 to seal each supply channel 11 fluid-tight at the transition to the piston unit 14. Each seal 12 is arranged within a sealing groove of the fluid guide unit 5.

[0075] As already indicated and in Fig. 3 and Fig. 5, the fluid guide unit 5 has a first and a second side S1, S2, wherein the piston units 14 of the displacement device 2 are arranged on the first side S1.

[0076] Strictly speaking, the piston units 14 of the displacement device 2 and one sealing groove per seal 12 of the fluid guide unit 5 are arranged on the first side S1.

[0077] On the second side S2, however, the closure unit 8 is arranged. Furthermore, the second side S2 has the fluid guide channel 6 (cf. Fig. 3 and Fig. 5).

[0078] With a view to Fig. 1A, Fig. 1B, Fig. 2 and Fig. 4 it can be seen that the fluid guide unit 5 comprises, in addition to the fluid guide channel 6 and the inlet 7, an outlet 13 for heat dissipation of a pressurizable fluid.

[0079] The inlet and outlet 7, 13 are formed by two holes that intersect each other at a vertical angle (cf. Fig. 4). The inlet and outlet 7, 13 each have a connection opening to which the braking device 1 can be connected to a fluid supply system. Within the connection openings of the inlet and outlet 7, 13, Fig. 1A to 5 closures used.

[0080] The part or area of ​​the fluid guide unit 5 with the inlet and outlet 7, 13 has a greater material thickness than the part or area of ​​the fluid guide unit 5 with the fluid guide channel 6.

[0081] The inlet and outlet 7, 13 are fluidly connected to the fluid guide channel 6 (cf. e.g. Fig. 4), so that pressurizable fluid can flow into the supply device 4 through the inlet 7 and, after flowing through the fluid guide channel 6, flow out through the outlet 13. Thus, heat generated in the piston units 14 during deceleration can be dissipated.

[0082] In the Fig. 3 and Fig. 5 shows an example of a piston unit 14, each piston unit 14 having a housing 15 and a piston 16 displaceable therein.

[0083] The housing 15 has a cylindrical cavity in which the piston 16 can be displaced. A pressure chamber D is formed between the piston 16 and the housing 15. The piston 16 can be moved from a retracted state (shown in all figures) to an extended state and vice versa, with the pressure chamber D having a larger volume in the extended state than in the retracted state.

[0084] The housing 15 is attached to the supply device 4 or to its fluid guide unit 5 by means of screws (cf. e.g. Fig. 5).

[0085] The piston 16 has a piston element 17 for contacting the connecting device 3 of the braking device 1, wherein the piston element 17 has a seal 18 for sealing the pressure chamber D and a sliding band 19 for improved mobility of the piston 16 relative to the housing 15.

[0086] Furthermore, the Fig. 3 and Fig. 5, the piston 16 comprises a guide element 20, wherein the pressure chamber D is formed between the guide element 20 and the housing 15. The guide element 20 serves to improve the guidance of the piston 16 within the housing 15 or within the cylindrical cavity of the housing 15, as well as to simplify insertion into the cavity. The piston element 17 and the guide element 20 are fastened to one another by means of a screw.

[0087] Each piston unit 14 further has a bellows 21 which is attached to the piston 16 or to its piston element 17 and the housing 15 in order to prevent the penetration of unwanted fluids or particles between the housing 15 and the piston 16.

[0088] Furthermore, Fig. 3 and Fig. 5, the displacement device 2 comprises a spring holder 22 for each piston unit 14, which is screwed to the housing 15 of the piston unit 14. The bellows 21 is clamped between the spring holder 22 and the housing 15.

[0089] In addition (cf. Fig. 3 and Fig. 5) the displacement device 2 has two spring plates 23 and a return element 24 per piston unit 14, both of which are movable relative to the spring holder 22 of the displacement device 2.

[0090] The two spring plates 23 and the return element 24 are rigidly connected to each other by means of screws. The return element 24 contacts the piston 16 of the piston unit 14 or its piston element 17 in order to return the piston 16 from an extended state to a retracted state.

[0091] Furthermore, the displacement device 2 has two spring elements 25 per piston unit 14, which are arranged between a spring plate 23 and the spring holder 22 to return the return element 24 to its initial position. In the initial position, the displacement device 2 exerts no or only a very small force on the connecting device 3, so that the latter cannot force-fit the braking device 1 to a vehicle wheel or to a transmission device of an electric axle drive device in order to decelerate a vehicle wheel or the transmission device.

[0092] As already mentioned, the displacement device 2 has a plurality of piston units 14, namely six, which are evenly distributed along the spatial course of the connecting device 3 in order to be able to displace the connecting device 3 evenly and without tilting (cf. e.g. Fig. 1A to 2).

[0093] In addition, the Fig. 3 and Fig. 5, that the connecting device 3 has a pressure distribution unit 26 which distributes the acting pressure, generated by displacement of the piston units 14, evenly along the spatial course of the pressure distribution unit 26.

[0094] The pressure distribution unit 26 has a shape similar to a hollow cylinder or a shape similar to an annular disc, wherein the pressure distribution unit 26 comprises a receiving area 27 for the arrangement of disc elements in order to realize a non-rotating or rotationally fixed part of a multi-disk brake.

[0095] The braking device 1 presented above can be used, for example, in an electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle.

[0096] In such a case, for example, the axle drive device has, in addition to the braking device 1, as shown above, an electric machine and a transmission device connected to the electric machine.

[0097] The transmission device can be connectable to one or more vehicle wheels, wherein the transmission device can comprise multi-disk elements in order to realize a rotating part of a multi-disk brake.

[0098] Furthermore, the braking device 1 with its connecting device 3 and the transmission device can be operatively connected so that a ring gear of the transmission device can be slowed down.

[0099] Below are the Fig. 1A to 5 are described again in different words.

[0100] Roughly summarized, each housing 15 of a piston unit 14 has a bore on the underside.

[0101] In order to ensure the supply of a pressurizable fluid to each housing 15 of a piston unit 14, an annular assembly or a supply device 4 is mounted below, consisting of two components screwed together and sealed to one another (housing distributor or fluid guide unit 5 and housing cover or closure unit 8).

[0102] In the fluid guide unit 5, a channel or a fluid guide channel 6 is introduced as a groove, which together with transverse bores or supply channels 11 ensures the distribution of a pressurizable fluid to the individual piston units 14.

[0103] The seal between the fluid guide unit 5 and the closure unit 8 is provided by two seals 9, 10 or O-rings or similar sealing elements. The seal between the housings 15 and the housing distributor or the fluid guide unit 5 is also provided by small annular sealing rings or seals 12.

[0104] In a special version of the arrangement shown, the O-rings or seals 9, 10 can also be omitted. For this purpose, the housing distributor or fluid guide unit 5 and the housing cover or closure unit 8 are fused together and manufactured using an additive (3D printing) process. List of reference symbols 1 braking device 2 shifting device 3 Connecting device 4 Supply facility 5 Fluid guide unit 6 Fluid guide channel 7 Entrance 8 locking unit 9 Seal 10 Seal 11 Supply channel 12 Seal 13 Outlet 14 Piston unit 15 housings 16 pistons 17 Piston element 18 Seal 19 sliding belt 20 guide element 21 Bellows 22 pen holders 23 spring plates 24 Reset element 25 spring element 26 Pressure distribution unit 27 Recording area D Pressure chamber S1 first page S2 second page

Claims

[1] Braking device (1) for an electric axle drive device comprising: a displacement device (2) for displacing a connecting device (3) of the braking device (1), by means of which the braking device (1) can be non-positively connected to a vehicle wheel or to a transmission device of an electric axle drive device in order to slow down a vehicle wheel or the transmission device, wherein the displacement device (2) comprises at least one piston unit (14), with the aid of which a connecting device (3) of the braking device (1) can be displaced, and a supply device (4) for supplying the displacement device (2) with a pressurizable fluid, whereby the supply device (4) has a fluid guide unit (5) which guides a pressurizable fluid to at least one piston unit (14), so that the at least one piston unit (14) can be supplied with a pressurizable fluid, wherein the fluid guide unit (5) comprises a fluid guide channel (6) and an inlet (7), wherein the fluid guide channel (6) is designed as a groove and connects the inlet (7) with the at least one piston unit (14) in a fluid-communicating manner, characterized by that the supply device (4) comprises a closure unit (8) which is designed as a circular disc and is arranged on the fluid guide unit (5) in order to close the fluid guide channel (6), - wherein the fluid guide unit (5) is designed as a circular disc having a first and a second side (S1, S2), - wherein the at least one piston unit (14) of the displacement device (2) is arranged on the first side (S1), and wherein the closure unit (8) is arranged on the second side (S2). [2] Braking device according to claim 1, wherein the fluid guide channel (6) follows the course of the supply device (4), and / or wherein the fluid guide channel (6) has a curved or annular course. [3] Braking device according to one of the preceding claims, wherein the fluid guide unit (5) or the closure unit (8) for the at least one piston unit (14) of the displacement device (2) comprises at least one supply channel (11) which fluidly connects the fluid guide channel (6) to a pressure chamber (D) of the at least one piston unit (14). [4] Braking device according to one of the preceding claims, wherein the at least one piston unit (14) comprises a housing (15) and a piston (16) displaceable therein, wherein the housing (15) has a cylindrical cavity in which the piston (16) is displaceable. wherein a pressure chamber (D) is formed between the piston (16) and the housing (15), wherein the housing (15) is attached to the supply device (4) or to its fluid guide unit (5), and wherein the piston (16) comprises a piston element (17) for contacting the connecting device (3) of the braking device (1). [5] Braking device according to one of the preceding claims, wherein the displacement device (2) comprises at least one spring holder (22) per piston unit (14), which is connected, e.g. screwed, to a housing (15) of the at least one piston unit (14), wherein the displacement device (2) comprises at least one spring plate (23) and at least one return element (24) per piston unit (14), both of which are movable relative to at least one spring holder (22) of the displacement device (2), and wherein the displacement device (2) comprises at least one spring element (25, 26) per piston unit (14), which is arranged between at least one spring plate (23) of the displacement device (2) and at least one spring holder (22) of the displacement device (2) in order to return at least one return element (24) of the displacement device (2) to its initial position. [6] Braking device according to one of the preceding claims, wherein the displacement device (2) comprises a plurality of piston units (14) or at least two piston units (14) which are distributed evenly along the spatial course of the connecting device (3) in order to displace the connecting device (3) evenly and without tilting, [7] Braking device according to one of the preceding claims, wherein the connecting device (3) comprises a pressure distribution unit (26) which distributes the acting pressure, generated by displacement of the at least one piston unit (14), evenly along the spatial course of the pressure distribution unit (26). [8] An electric axle drive device for driving one or more vehicle wheels of an electric or hybrid vehicle, comprising: a braking device (1) according to one of the preceding claims.

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