BRAKING DEVICE FOR A MOTOR VEHICLE

Description

[0001] The invention relates to a braking device for a motor vehicle according to the preamble of patent claim 1.

[0002] DE 101 41 794 A1 discloses a hydrodynamic retarder for a motor vehicle with a circuit for controlling the retarder, which circuit contains a hydraulic pump, a heat exchanger, a valve and a control and regulating unit, wherein the delivery volume of the pump is adjustable such that the volume flow can be adjusted depending on the vehicle speed or the propeller shaft speed or the retarder speed.

[0003] In addition, DE 10 2020211041 A1 shows a braking device with a hydrodynamic retarder, in which a control unit controls both the filling of the retarder and the clutch via valves.

[0004] Furthermore, DE 10 2021121407 A1 shows a vehicle coolant circuit for dissipating heat from a vehicle component. This component may be a retarder. An impeller pump is used to increase the fluid pressure in the circuit.

[0005] WO 2019 / 074419 A1 also discloses a hydrodynamic retarder with a valve-controlled displacement volume. The retarder comprises a conveying system with a working chamber and a pressure generator connected to the working chamber. This pressure generator is designed to achieve the emptying of the working chamber.

[0006] The object of the present invention is to provide a braking device for a motor vehicle so that the installation space and costs of the braking device can be kept particularly low.

[0007] This object is achieved according to the invention by a braking device for a motor vehicle having the features of patent claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0008] The invention relates to a braking device for a motor vehicle, which is preferably designed as a commercial vehicle, in particular as a heavy commercial vehicle. The motor vehicle can be designed as a motor vehicle, in particular as a passenger car, commercial vehicle or truck, or as a passenger bus. The motor vehicle can be, for example, a battery-electric vehicle, a fuel cell vehicle, or a hybrid vehicle. For example, the motor vehicle can have an internal combustion engine, by means of which the motor vehicle can be at least partially driven. Preferably, the braking device is provided to decelerate the motor vehicle. As a result, a speed at which the motor vehicle travels on a roadway can be reduced by means of the braking device. The motor vehicle can be decelerated, for example, to a standstill by means of the braking device.

[0009] The braking device comprises a fluid path through which a fluid can flow and at least two line sections through which the fluid can flow, which can be referred to in particular as a hydraulic system. At least one pump element, referred to in particular as an oil pump, is arranged in the fluid path for conveying the fluid through the fluid path. The pump element is preferably designed as an electric pump.

[0010] At least one valve device is arranged in the fluid path, through which fluid can flow, has at least one valve inlet and at least one valve outlet spaced from the valve inlet, and is movable between at least two valve positions. The valve device is fluidly connected or connectable to the pump element by means of a first of the line sections. In other words, the first line section is provided to fluidly connect a pump outlet of the pump element, through which fluid can flow, to the valve inlet of the valve device. The fluid can flow through the valve inlet and the valve outlet.

[0011] The braking device comprises at least one retarder, which has a stator, a rotor formed separately from the stator and rotatable about an axis of rotation relative to a housing element of the retarder, and a retarder input.

[0012] The fluid can be supplied to the retarder via the retarder inlet. The retarder is fluidly connected, or connectable, to the valve device via the valve outlet via the second of the line sections. In other words, the second line section is intended to fluidly connect the valve outlet of the valve device to the retarder inlet. Because the braking device includes the retarder, the braking device can be referred to, in particular, as a retarder system.

[0013] In a first valve position of the valve device, the valve inlet is fluidically connected to the valve outlet, whereby the fluid flowing through the first line section can be fed to the retarder inlet via the valve inlet, through the valve device, via the valve outlet and the second line element. In the second valve position of the valve device, the valve inlet is not fluidically connected to the valve outlet, whereby the fluid flowing through the first line section cannot flow through the valve device and thus cannot be fed to the retarder inlet via the second line element. In the first valve position, the fluid flows through the first line section in a first flow direction of the first line section.

[0014] For example, the valve device has a through-channel through which the fluid can flow and which is fluidically connected to the valve inlet and the valve outlet. For example, in the first position the through-channel is open, whereby the fluid flowing through the first line section can be fed to the retarder inlet via the valve inlet, via the through-channel, via the valve outlet and via the second line element. For example, in the second position the through-channel is blocked, whereby the valve inlet and the valve outlet are not connected to one another. As a result, in the second valve position the fluid flowing through the first line section cannot be fed to the retarder inlet via the valve inlet, the through-channel, the valve outlet and via the second line element. The valve device can in particular be referred to as a valve block. The valve device is preferably designed as a directional valve.

[0015] In order to keep the installation space and costs of the braking device particularly low, the braking device has at least one coupling element, via which the rotor of the retarder can be coupled to a drive shaft of the motor vehicle and decoupled from the drive shaft, and a coupling device. The drive shaft can be rotated about a shaft rotation axis of the drive shaft relative to the housing element. The drive shaft can be driven, for example, by an electric machine of the motor vehicle and / or by the internal combustion engine, whereby wheels of the motor vehicle can be driven via the drive shaft. Coupling the rotor to the drive shaft means that the rotor can be coupled to the drive shaft in a torque-transmitting or rotationally fixed manner, whereby, for example, a torque provided by the drive shaft can be transmitted to the rotor.

[0016] By means of the coupling device, the rotor and the drive shaft can be coupled by moving the valve device into the first valve position via the coupling element and decoupled by moving the valve device into the second position. In other words, the coupling element and the valve device are coupled via the coupling device in such a way that the rotor and the drive shaft are coupled to one another via the coupling element in the first valve position and are decoupled from one another in the second valve position. In other words, the valve device has at least one adjustable connecting means, wherein the coupling element is coupled to the connecting means via the coupling device in such a way that the first valve position results in an open coupling element and the second valve position results in a closed coupling element.

[0017] The clutch element is arranged between the drive shaft and the rotor with respect to a torque flow running from the drive shaft to the rotor, via which the torque can be transmitted from the drive shaft to the rotor, so that the torque flow runs via the clutch element, particularly when the clutch element is closed. Alternatively, the torque flow can run in the opposite direction from the rotor to the drive shaft via the clutch element. The clutch element has, for example, a first clutch part and a second clutch part. The first clutch part can be connected in a rotationally fixed manner to the drive shaft, and the second clutch part can be connected in a rotationally fixed manner to the rotor.

[0018] The clutch element can be opened and closed, meaning that the clutch element can be switched between an open state and a closed state. In the open state, the drive shaft is decoupled from the rotor. In the closed state, the drive shaft is coupled to the rotor. In the open state, the two clutch parts of the clutch element, or the drive shaft and the rotor, are decoupled from one another, so that, for example, no torque or at most a first torque that is greater than zero can be transmitted between the two clutch parts, or between the drive shaft and the rotor.In the closed state, the two clutch parts are connected to one another in a torque-transmitting manner, in particular frictionally and / or positively and / or non-positively, in such a way that a second torque which is greater than the first torque can be transmitted between the clutch parts or between the drive shaft and the rotor.

[0019] A rotationally fixed connection is understood to mean a connection between two components which are formed separately from one another and which are connected to one another in such a way that at least relative rotations between the components and preferably relative movements between the components in the axial direction and in the radial direction of the components are avoided or prevented.

[0020] The clutch element can be referred to, in particular, as a clutch or a separating clutch. The clutch element can be designed as a positive-locking clutch, in particular as a claw clutch. Furthermore, the clutch element can be designed as a friction clutch, in particular as a friction or multi-disk clutch. The drive shaft can, for example, be a transmission shaft of a motor vehicle's transmission or can be connected or connectable to the transmission shaft in a torque-transmitting manner.

[0021] If the drive shaft and the rotor are coupled to one another via the closed coupling element, the rotor can be driven by the drive shaft and thus rotated about its axis of rotation relative to the housing element. The fluid supplied to the retarder via the retarder inlet can be accelerated by the rotor, as a result of which the rotor can be decelerated. For example, the fluid can be guided in or to the stator as a result of the acceleration and guided from the stator back to the rotor, as a result of which the rotor can be decelerated. In other words, the rotor acts on the fluid, and the rotor is decelerated as a result of the actuation. Deceleration can be understood in particular to mean that the rotational speed of the rotor is lower than if the fluid is not acted upon by the rotor. The deceleration of the rotor can in particular be referred to as deceleration.As a result of the rotor deceleration, the clutch element being closed causes the drive shaft to be decelerated or braked by the retarder, in particular the rotor. This allows the motor vehicle to be decelerated by means of the braking device, in particular the retarder. Because the rotor can be decelerated by the fluid, the fluid can be referred to, in particular, as brake fluid. The retarder can, in particular, be referred to as an oil retarder.

[0022] In a motor vehicle designed as a battery-electric or fuel cell vehicle, the braking device is preferably provided as an additional brake. This can be understood in particular to mean that the motor vehicle has at least one brake, in particular a mechanical one, designed separately from the braking device, by means of which the motor vehicle can be decelerated. For example, when braking or decelerating the motor vehicle, braking power can be provided partly by the braking device and partly by the brake. Alternatively or additionally, the braking device can be provided in the motor vehicle as a continuous brake. Because the braking device has the retarder, the braking device can in particular be referred to as a hydrobrake.

[0023] The invention is based in particular on the following findings and considerations: A conventional braking device, in particular an auxiliary brake or continuous brake, can in particular be designed as an electromotive brake, which can in particular be referred to as an electric generator brake. In this case, overload protection must be provided for the electric machine of the motor vehicle and for an energy storage device, in particular a battery, of the motor vehicle when the energy storage device is fully charged. In addition, a continuous braking power of the conventional braking device is limited by a maximum generator motor power of the electromotive brake, in particular including an inverter power of an inverter. In this case, auxiliary consumers, for example a fan, cannot usually increase a maximum braking power, in particular a continuous braking power, of the conventional braking device.The conventional braking system can be particularly complex and, for example, require a particularly large amount of installation space and be particularly expensive.

[0024] In contrast, the braking device according to the invention has the retarder, whereby the braking device according to the invention does not have the disadvantages of the electromotive brake. Because the braking device according to the invention has the coupling device, an adjusting element designed separately from the coupling device or from the valve device for opening or closing the clutch element can be omitted. Thus, the supply of the fluid to the retarder and the clutch actuation or a respective clutch position can be realized by means of exactly one valve device. Furthermore, a displacement device for the rotor displacement, in particular axial displacement of the rotor, can be omitted. As a result, the costs and installation space of the braking device or a retarder assembly of the retarder can be kept particularly low. Furthermore, a particularly high degree of system integration can be achieved.In addition, the braking device or retarder can be designed or manufactured with particularly little effort, since, for example, the adjusting element or the rotor displacement can be omitted.

[0025] The braking device according to the invention is particularly suitable for use in a battery-electric vehicle, a fuel cell vehicle, or a conventional vehicle that includes, for example, the internal combustion engine. Furthermore, the braking device preferably comprises separately and easily replaceable components or assemblies, such as the pump element, the valve device, or the hydraulic system. This allows, for example, maintenance and / or repair costs of the braking device or the motor vehicle to be kept particularly low. Furthermore, a seal between the drive shaft and the retarder, in particular the rotor, can be omitted. Furthermore, a draining device can be omitted.

[0026] In a further embodiment of the invention, the valve device has a valve spool which is movable between at least two positions and is arranged in a first position in the first valve position and in the second valve position. In other words, the valve device or the connecting means has the valve spool, referred to in particular as a spool, which is translationally displaceable relative to the housing element between the at least two positions, wherein the valve spool is in the first position in the first valve position of the valve device and is in the second position in the second valve position of the valve device. The valve spool can be designed, for example, as a switching piston or as a control piston.The coupling device is designed as an actuator mechanically coupled to the valve spool, which actuator is movable between at least two actuator positions, wherein the actuator is movable into a first of the actuator positions by moving the valve spool into the first position, whereby the rotor and the output shaft are coupled via the coupling element, and is movable into the second actuator position by moving the valve spool into the second position, whereby the rotor and the output shaft are decoupled from one another. In other words, the actuator is mechanically coupled to the valve spool in such a way that the actuator is movable or is moved into the first actuator position as a result of moving the valve spool into the first position, and the actuator is movable or is moved into the second actuator position as a result of moving the valve spool into the second position.The actuator is mechanically coupled to the clutch element such that the rotor and the drive shaft are coupled to each other via the clutch element in the first actuator position and decoupled from each other in the second actuator position. As a result, the clutch element can be actuated particularly advantageously via the coupling device by moving the valve device between the valve positions or into the valve positions. The actuator is preferably designed as a shift fork, for example, as a linkage.

[0027] In a further embodiment, the braking device has at least one cooler arranged in the fluid path and through which the fluid can flow, by means of which heat can be dissipated from the fluid, and / or a hydraulic sump that can be fluidly connected or connected to the fluid path. This can be understood in particular as the following: The fluid path comprises the cooler, through which the fluid flowing through the fluid path can flow, wherein, as a result of the flow, heat from the fluid flowing through the cooler can be dissipated from the fluid by means of the cooler, whereby the fluid can be cooled by means of the cooler. As a result, the temperature of the fluid can be kept particularly low.Alternatively or additionally, the braking device comprises the hydraulic sump, in particular referred to as an oil sump, which comprises at least one receiving space in which the fluid can be received, wherein the hydraulic sump is fluidly connectable or connected to the fluid path, whereby the fluid received in the hydraulic sump can be at least partially discharged from the hydraulic sump and introduced into the fluid path and / or the fluid flowing through the fluid path can be at least partially discharged from the fluid path and introduced into the hydraulic sump. The fluid can be stored particularly advantageously by means of the hydraulic sump, wherein the fluid path can be supplied with the fluid particularly advantageously, for example, via the hydraulic sump.

[0028] The cooler is preferably designed as a heat exchanger. The heat exchanger can, for example, be designed as a rotary heat exchanger, which can be referred to in particular as a rotary heat exchanger (RHE). In other words, the heat exchanger preferably has an RHE frame.

[0029] Preferably, the fluid is usable or used as transmission oil for the transmission. This can be understood, in particular, as meaning that the hydraulic sump is designed as a shared hydraulic sump for the braking device and the transmission, i.e., the braking device and the transmission share a shared fluid or oil supply.

[0030] In a further embodiment, it is provided that the cooler is arranged in a third line section of the fluid path, which is formed separately from the first and second line sections and through which the fluid can flow, wherein the third line section is fluidically connected to the first line section via a connection point, such that the fluid flowing through the first line section can be conveyed to the valve inlet, at least partially bypassing the cooler. In other words, the first line section has the connection point by means of which the pump outlet is fluidically connected to the cooler, wherein the pump outlet is fluidically connected to the valve inlet by means of the first line section, bypassing the cooler, the retarder, and the hydraulic sump.As a result, the fluid flowing through the third line section can be cooled particularly advantageously by means of the cooler, whereby the temperature of the fluid can be kept particularly low. The fluid flowing through the cooler can be taken from the third line section via the connection point, introduced into the first line section, and there guided to the pump element via the pump outlet in a second flow direction opposite to the first line section, or introduced into the pump element.

[0031] In a further embodiment, the third line section is fluidically connected to a retarder outlet of the retarder, whereby the fluid can be discharged from the retarder via the retarder outlet and fed to the cooler. In other words, the cooler is arranged downstream of the retarder outlet and upstream of the connection point in the flow direction of the fluid discharged from the retarder via the retarder outlet and introduced into the third line section, whereby the fluid discharged from the retarder can be cooled by means of the cooler. A branching point is arranged in the third line section, via which the cooler is or can be fluidically connected to the hydraulic sump, bypassing the pump element, the retarder, and the valve device.In other words, the third line section has the branching point, by means of which at least a portion of the fluid contained in the hydraulic sump can be discharged from the hydraulic sump and introduced into the third line section, and can be fed directly to the cooler via the third line section. In other words, the branching point is arranged in the third line section between the retarder outlet and the cooler in the flow direction of the fluid flowing from the retarder outlet to the cooler, wherein the connection point is fluidly connectable or connected to the hydraulic sump.The fluid can be taken from the hydraulic sump and introduced into the third line section via the branching point and passed through the cooler, whereby the fluid, in particular the transmission oil, can be cooled particularly advantageously, whereby the temperature of the fluid, in particular the transmission oil, can be kept particularly low.

[0032] The cooling of the fluid can take place both during braking, by leading the fluid from the retarder outlet through the third line section through the cooler, and when the retarder is switched off or the rotor is decoupled, by taking the fluid from the hydraulic sump, introducing it into the third line section via the third branching point and leading it through the cooler.

[0033] In a further embodiment, the first line section has a withdrawal point via which the pump element is or can be fluidly connected to a control connection of the valve device, whereby the control connection can be acted upon by the fluid by means of the pump element, whereby the valve device can be moved from the second valve position to the first valve position. In other words, the pump outlet is fluidly connected to the control connection of the valve device via the withdrawal point, either directly or by bypassing the cooler and the retarder.In other words, at least a portion of the fluid conveyed through the first line section by the pump element can be removed from the first line section at the removal point and fed to the control connection, whereby the valve device, in particular the valve slide, can be actuated by the fluid via the control connection. As a result of the actuation, the valve device can be moved from the second position to the first position or the valve slide can be moved from the second position to the first position. As a result, the valve device can be actuated by means of the pump element by adjusting a fluid pressure of the fluid, and thus the coupling element can be actuated.As a result, the clutch device can be actuated or closed by means of the oil pump, in particular an electric one, thus eliminating the need for a control system for the clutch element in addition to the oil pump. Thus, the valve device is preferably a hydraulic switching valve. In other words, a hydraulic switching of the valve device is coupled to a clutch actuation. The extraction point is preferably arranged downstream of the branching point in the flow direction of the fluid flowing from the pump element to the valve inlet.

[0034] In a further embodiment, the fluid path comprises a fourth line section which is formed separately from the line sections and through which the fluid can flow, via which the pump element and the valve device are fluidically connected, bypassing the first line section, the retarder, the valve inlet, the valve outlet, and the cooler. In other words, the pump element has a pump inlet through which the fluid can flow, which is spaced apart from the pump outlet, in particular formed separately from the pump outlet, and which is or can be fluidically connected to the valve device via the fourth line section, bypassing the pump outlet, the first line section, the retarder, the valve inlet, the valve outlet, and the cooler. The fluid flowing through the fourth line section can be supplied to the pump element via the pump inlet and thus introduced into the pump element.The fluid flows through the fourth line section in a first flow direction of the fourth line section.

[0035] Preferably, it is provided that the valve device has at least one second valve inlet through which the fluid can flow, which is spaced from the valve inlet and fluidically connected or connectable to the fourth line section, and at least one second valve outlet through which the fluid can flow, which is spaced from the valve outlet and fluidically connected or connectable to the hydraulic sump, wherein in the second valve position, the fluid flowing through the fourth line section in a second flow direction of the fourth line section opposite to the first flow direction of the fourth line section can be introduced via the second valve inlet, through the valve device, and via the second valve outlet into the hydraulic sump.In other words, the pump element is fluidically connected via the fourth line section, bypassing the first line section, the retarder, the valve inlet, the valve outlet, and the cooler, to the second valve inlet, which is formed separately from the valve inlet and the valve outlet, wherein the valve device comprises the second valve outlet, which is formed separately from the valve inlet, the valve outlet, and the second valve inlet, and which is fluidically connected to the hydraulic sump, bypassing the retarder and the cooler. In the second valve position, the second valve inlet is fluidly connected to the second valve outlet. As a result, for example, in particular by means of the pump element, the fluid can be withdrawn from the hydraulic sump, introduced into the third line section via the branching point, cooled by the cooler, and introduced into the first line section via the connection point.The fluid flowing through the first line section can then be fed to the pump element via the pump outlet and discharged from the pump element via the pump inlet and introduced into the fourth line section. The fluid flowing through the fourth line section in the second flow direction of the fourth line section can then be introduced into the hydraulic sump via the valve device, in particular via the second valve inlet and the second valve outlet. This allows the fluid cooled by the cooler to be returned to the hydraulic sump.

[0036] For example, the valve device has a second through-channel which is formed separately from the through-channel, spaced from the through-channel, and through which the fluid can flow, and which can be connected to the second valve inlet and the second valve outlet. The second through-channel is not connected, in particular not directly, to the through-channel. In the second valve position, the second through-channel is at least partially open, as a result of which the fluid can flow through the second through-channel and can thus be guided from the second valve inlet to the second valve outlet. In the first valve position, the second through-channel is blocked, as a result of which the second valve inlet and the second valve outlet are not fluidically connected to one another, such that the guidance of the fluid from the second valve inlet to the second valve outlet does not take place.

[0037] In a further embodiment, it is provided that the braking device has a second connection point arranged in the fourth line section, via which second connection point the fluid flowing through the fourth line section is or can be fluidically connected to the hydraulic sump, bypassing the retarder, the valve device, and the cooler. In other words, the fourth line section has the second connection point, via which the hydraulic sump is or can be fluidically connected to the pump inlet. As a result, the fluid can be sucked in by means of the pump element and thus removed from the hydraulic sump and fed to the retarder via the retarder inlet via the fourth line section, the pump element, in particular the second pump inlet and the pump outlet, via the first line element, the valve device, in particular the valve inlet and the valve outlet, and the second line element.This allows the rotor to be braked using the fluid supplied to the retarder.

[0038] In a further embodiment, it is provided that the valve device has at least one second control connection spaced from the control connection and fluidically connected to the fourth line section, which can be acted upon by the fluid via the fourth line section by means of the pump element, whereby the valve device can be moved from the first position to the second position. In other words, the fourth line section has a third connection point formed separately from the second connection point, by means of which the pump inlet of the pump element is connected or can be connected to the second control connection of the valve device, bypassing the valve device, bypassing the retarder, and bypassing the cooler.In other words, at least a portion of the fluid flowing through the fourth line section in the second flow direction of the fourth line section can be withdrawn from the fourth line section via the third connection point and fed to the second control port, whereby the latter is pressurized by the fluid, wherein the valve device is movable or is moved from the first position to the second position as a result of the pressurization. As a result, a fluid pressure of the fluid can be provided at the second control port by means of the pump element, as a result of which the valve device can be moved from the first position to the second position. The actuation of the coupling element can thus be carried out by means of the pump element, whereby no control provided in addition to the pump element is required for the actuation of the coupling element.In other words, a hydraulic switching of the valve device is coupled with a clutch actuation.

[0039] Preferably, an electronic computing device is provided, by means of which the braking device is activated and / or regulated or controlled and / or monitored via the pump element.

[0040] In a further embodiment, a check valve through which the fluid can flow is arranged in the second line section between the retarder inlet and the valve outlet. Preferably, the first check valve is designed to allow the fluid to flow from the valve outlet through the first check valve to the retarder inlet and to prevent the fluid from flowing from the retarder inlet to the valve outlet.

[0041] In a further embodiment, a second check valve through which the fluid can flow is arranged in the second line section between the retarder outlet and the cooler, in particular the branching point. The second check valve is preferably designed to permit a flow from the retarder outlet through the second check valve to the cooler, in particular the branching point, and to prevent an opposite flow of the fluid from the cooler, in particular the branching point, to the retarder outlet.

[0042] In a further embodiment, a third check valve through which the fluid can flow is arranged in the third line section between the hydraulic sump and the branching point. The third check valve is preferably designed to allow the fluid to flow from the hydraulic sump through the third check valve to the branching point and to prevent an opposite flow of the fluid from the branching point to the hydraulic sump.

[0043] In a further embodiment, a fourth check valve through which the fluid can flow is arranged in the fourth line section between the pump element, in particular the second connection point, and the valve device, in particular the third connection point. The fourth check valve is preferably designed to permit a flow of fluid from the pump element, in particular the second connection point, through the fourth check valve to the valve device, in particular the third connection point, and to prevent an opposite flow of fluid from the valve device, in particular the third connection point, to the pump element, in particular the second connection point.

[0044] In a further embodiment, a fifth check valve through which the fluid can flow is arranged in the fourth line section between the hydraulic sump and the second connection point. The fifth check valve is preferably designed to permit a flow of fluid from the hydraulic sump to the second connection point and to prevent an opposite flow of fluid from the second connection point to the hydraulic sump.

[0045] For example, at least one of the check valves can have a spring element, in particular a contact spring. This allows, for example, the respective flow of the fluid to be permitted starting at a certain fluid pressure, whereby the minimum fluid pressure required for this depends on the spring element, in particular on the stiffness of the spring element.

[0046] In an operating state of the braking device, particularly referred to as synchronization, the valve device is initially in the second valve position. The fluid is pumped through the first line section by means of the pump element, as a result of which the fluid pressure in the first line section can be built up. The control connection is thereby acted upon by the fluid or the pressure of the fluid, as a result of which, in particular because the pressure of the fluid at the control connection is greater than at the second control connection, the valve device is moved from the second valve position towards the first valve position. The valve spool can thereby be moved from the second position towards the first position and the actuator can be moved from the second actuator position towards the first actuator position.This allows the rotational speeds of the rotor and the drive shaft to be synchronized, particularly locked, by means of the coupling element or a synchronizing device. When the valve device has moved into the first valve position as a result of the continued application of fluid or pressure to the control port, the rotational speeds of the rotor and the drive shaft are synchronized. This can be referred to, in particular, as synchronous switching. The valve spool is then in the first position and the actuator is in the first actuator position.

[0047] In addition to actively controlling or regulating the braking system, especially the retarder, through the pump element, the synchronization is also activated by the same pump element. This eliminates the need for a separate control for the synchronization device.

[0048] After synchronization, the braking device can transition into an operating mode, particularly referred to as standby mode, or into an operating mode, particularly referred to as braking mode. In braking mode, the pump element builds up pressure or modulates the pressure of the fluid in the first line section, wherein the pressure build-up can, for example, be greater than the pressure build-up during synchronization. Because the valve device is in the first valve position, the fluid can be introduced into the retarder by means of the pump element via the first line section through the valve device, in particular via the valve inlet and the valve outlet, via the retarder inlet, whereby the pressure of the fluid in the retarder can be particularly increased. As a result, a braking torque for braking the drive shaft can be built up by means of the braking device, in particular the retarder.This braking torque can be limited, for example, if a fluid temperature exceeds a threshold value. For this purpose, a temperature sensor for detecting the fluid temperature can be provided in the fluid path, preferably in the third line section. If the temperature detected by the temperature sensor is higher than the threshold value, the braking torque can be limited.

[0049] In standby mode, the pressure of the fluid in the first line section is or will be reduced by the pump element compared to the braking mode. Thus, relative to the braking mode, the pressure of the fluid is reduced. It is preferably provided that the pump element prevents the fluid from building up pressure in the fourth line section, whereby the second control connection is preferably not acted upon by the fluid. The synchronization of the rotational speeds of the rotor and the drive shaft remains active. The valve device remains in the first valve position, the valve spool remains in the first position, and the actuator remains in the first actuator position.

[0050] Another operating mode can in particular be referred to as shutdown. The shutdown can, for example, follow the standby mode. During shutdown, the fluid is pumped into the fourth line section by means of the pump element, whereby a pressure build-up of the fluid can be achieved in the fourth line section. As a result, the second control connection is acted upon by the fluid or the pressure of the fluid. In particular, because the pressure build-up takes place in the fourth line section, the pressure of the fluid in the second control connection is greater than in the first control connection. As a result, the valve device is moved from the first valve position towards the second valve position.The valve device can be moved from the first valve position to the second valve position or the valve device can be moved from the first valve position to an intermediate position which is located between the first and the second valve position. Preferably, the pump element in the first line section is in suction mode, i.e. the fluid flowing through the first line section is sucked in by the pump element, conveyed through the pump element and thus introduced into the fourth line section. As a result, the pressure of the fluid in the first line section can be particularly reduced compared to the braking mode and particularly increased in the fourth line section, whereby a pressure difference between the pressure of the fluid at the second control connection and the control connection can be particularly increased.By moving the valve device to the second valve position, the clutch element is opened, which deactivates the synchronization of the speeds of the rotor and the drive shaft.

[0051] Another operating mode can in particular be referred to as cooling mode. In this case, the fluid is sucked from the hydraulic sump by means of the pump element, fed to the cooler arranged in the third line section, and then introduced into the hydraulic sump via the fourth line section, the second valve inlet, and the second valve outlet. In this case, a filter element, in particular referred to as a bypass filter, can be arranged upstream of the cooler in the flow direction of the fluid guided to the cooler, in particular in the fourth line section. The fluid can flow through the filter element, whereby the fluid flowing through the filter can be filtered and thus cleaned by means of the filter element.

[0052] Preferably, the pump element is operated in the braking mode in a forward running mode, particularly referred to as forward operation, and in the cooling mode in a reverse running mode opposite to the forward running mode, particularly referred to as reverse operation.

[0053] In a further embodiment, the braking device has a shut-off device. The shut-off device is designed to increase the pressure of the fluid in the fourth line section particularly quickly, whereby the second control connection can be subjected to the pressure of the fluid, thereby moving the valve device particularly quickly from the first valve position to the second valve position.

[0054] In a further embodiment, the shutdown device is designed as a hydraulic shutdown device. The shutdown device has an inlet through which the fluid can flow and an outlet through which the fluid can flow, which is or can be connected fluidically to the second control connection. The hydraulic shutdown device is movable between at least two positions, wherein in a first of the positions the inlet and the outlet are fluidically connected, whereby the fluid can flow from the inlet through the shutdown device to the outlet, and in the second position the inlet is not fluidically connected to the outlet, whereby the fluid does not flow through the shutdown device. The shutdown device is provided as a safety shutdown, whereby the safety of the braking device against damage to or destruction of the braking device can be particularly increased.

[0055] For example, the inlet can be fluidically connected, in particular directly, to the first retarder outlet or to the second retarder outlet. In this case, in an operating mode referred to in particular as rapid shutdown or safety shutdown, which can follow the braking mode, for example, the hydraulic shutdown device can be moved from the second position to the first position. As a result, the fluid discharged from the retarder via the first retarder outlet or the second retarder outlet can be guided through the shutdown device, in particular via the inlet and the outlet, introduced into the fourth line section and supplied to the second control connection, whereby the pressure in the fourth line section, in particular in the second control connection, can be particularly increased.In particular, because the pressure at the second control port is then greater than the pressure of the fluid at the first control port, the valve device can be moved from the first valve position to the second valve position. This opens the coupling element, which can be referred to in particular as a separation of the rotor and the drive shaft. Optionally, it can be provided that, by means of the pump element, the pressure of the fluid in the first line section and thus at the control port can be particularly reduced during suction operation, whereby the pressure difference between the second control port and the control port can be particularly increased. The shutdown device can in particular be referred to as a mechanically coupled changeover valve.

[0056] Alternatively, the shutdown device can be designed as a pneumatic shutdown device. The pneumatic shutdown device is movable between at least two positions and has an inlet through which air can flow and an outlet through which air can flow, spaced from the inlet. The inlet is fluidically connected to a compressed air reservoir, by means of which the pneumatic shutdown device, in particular the inlet, can be supplied with compressed air. The pneumatic shutdown device has a pneumatic cylinder in which a piston element is accommodated so as to be movable in translation. The piston element can be moved in translation relative to a cylinder wall of the pneumatic cylinder between a first piston position and a second piston position. The cylinder has an opening through which air or compressed air can flow, which opening is or can be connected fluidically to the outlet.The piston element is mechanically connected or coupled to the valve device, in particular the valve slide and / or the coupling device.

[0057] In a first of the positions, the inlet is fluidically connected to the outlet, whereby the air from the reservoir can be introduced via the inlet and the outlet, through the opening into the cylinder, whereby the piston element is pressurised by compressed air. In the second of the positions, the inlet is not fluidically connected to the outlet, whereby the piston element is not pressurised with compressed air. By pressurising the piston element with compressed air, the piston element is moved from the first position to the second position. Because the piston element and the valve device are mechanically coupled, when the piston element is moved to the second piston position, the valve device is moved from the first valve position to the second valve position.

[0058] The rapid shutdown can be carried out more quickly than the deactivation, which can be understood in particular as meaning that the time period within which the valve device is moved from the first valve position to the second valve position is shorter during the rapid shutdown than during the deactivation. This can prevent, for example, premature and thus unintentional filling of the retarder with the fluid, which can prevent, for example, damage to or destruction of the braking device, in particular the clutch element or the coupling device. This can significantly increase the safety of the braking device.

[0059] Alternatively, for example, in the case of a battery-electric vehicle or a fuel cell vehicle, the switch-off device and thus the safety switch-off can be dispensed with if the electric machine for driving the motor vehicle can compensate for the braking torque in the case of an active anti-lock braking system (ABS) particularly quickly and thus quickly enough.

[0060] The shut-off device is preferably activated electrohydraulically or electropneumatically. This can be understood, in particular, that in the case of the shut-off device designed as a hydraulic shut-off device and in the case of the shut-off device designed as a pneumatic shut-off device, the respective shut-off device can be moved from the first position to the second position by means of an electric motor.

[0061] Preferably, the shutdown device has at least one spring element by means of which the shutdown device can be moved from the second position into the first position.

[0062] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0063] Showing: Fig. 1 shows a schematic partial sectional view of a braking device according to the invention in a first valve position; and Fig. 2 shows a schematic partial sectional view of a braking device according to the invention in a second valve position; and Fig. 3 shows a schematic partial sectional view of a braking device according to the invention in an intermediate position; and Fig. 4 shows a schematic partial sectional view of a braking device according to the invention according to a further embodiment.

[0064] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0065] Fig. 1 shows a schematic partial sectional view of a braking device 10 for a motor vehicle. The motor vehicle is preferably designed as a commercial vehicle.

[0066] For example, the motor vehicle is designed as a motor vehicle, in particular as a passenger car, commercial vehicle or lorry or as a passenger bus.

[0067] The braking device 10 comprises a fluid path 12 through which a fluid can flow, which can in particular be referred to as a hydraulic system. The fluid path 12 has at least two line sections 14, 16 through which the fluid can flow. At least one pump element 18 for conveying the fluid through the fluid path 12 is arranged in the fluid path 12. The pump element 18 is preferably designed as an electric pump. The pump element 18 designed as an electric pump can be driven by an electric motor 20. The pump element 18 is fluidically connected to a first of the line sections 14 via a pump outlet 24 of the pump element 18. At least one valve device 34 through which the fluid can flow, has at least one valve inlet 26 and one valve outlet 28, and is movable between at least two valve positions 30, 32, is arranged in the fluid path 12.The valve device 34 is fluidically connected to the first line section 14 via the valve inlet 26, whereby the valve inlet 26 is fluidically connected to the pump element 18, in particular the pump outlet 24. The valve device 34 has a through-channel 36 through which the fluid can flow and which is fluidically connectable to the valve inlet 26 and the valve outlet 28.

[0068] The braking device 10 has a retarder 38, which comprises a stator 40 and a rotor 42 formed separately from the stator 40 and rotatable about a rotational axis relative to a housing element of the retarder 38. The retarder 38 has a retarder inlet 44, via which the retarder 38 is fluidly connected to the valve device 34 via the valve outlet 28 by means of the second line section 16.

[0069] In a first of the valve positions 30, the valve inlet 26 is fluidically connected to the valve outlet 28 via the through-channel 36, whereby the fluid flowing through the first line section 14 can be fed via the valve inlet 26 through the valve device 34, via the valve outlet 28 and via the second line section 16 to the retarder inlet 44. As a result, the fluid can be introduced into the retarder 38. In the Fig. 1 the valve device 34 is in the first valve position 30.

[0070] Fig. 2 shows a schematic partial sectional view of the braking device 10, wherein the valve device 34 is in the second valve position 32. In the second valve position 32, the valve inlet 26 is not fluidically connected to the valve outlet 28, whereby the fluid flowing through the first line section 14 cannot reach the through-channel 28 via the valve inlet 26 and thus cannot be introduced into the second line section 16 via the valve outlet 28. As a result, in the second valve position 32, the fluid is not supplied from the first line section 14 via the valve device 34 to the retarder 38, in particular the retarder inlet 44.

[0071] A first check valve 45 through which the fluid can flow is arranged in the second line section 16 between the valve outlet 28 and the retarder inlet 44. The check valve 45 is designed to permit a flow of the fluid in a flow direction 46 from the valve outlet 28 through the check valve 45 to the retarder inlet 44 and to prevent a flow of the fluid from the retarder inlet 44 to the valve outlet 28 in a direction opposite to the flow direction 46.

[0072] In order to keep the installation space and costs of the braking device 10 particularly low, the braking device 10 has at least one coupling element 47, via which the rotor 42 can be coupled to a drive shaft 48 of the motor vehicle and decoupled from the drive shaft 48. In addition, the braking device 10 has a coupling device 50, by means of which the rotor 42 and the drive shaft 48 can be coupled by moving the valve device 34 into the first valve position 30 via the coupling element 47 and can be decoupled by moving the valve device 34 into the second valve position 32. When the valve device 34 is in the first valve position 30, the coupling element 47 is closed, whereby the drive shaft 48 and the rotor 42 are mechanically coupled. When the valve device 34 is in the second valve position 32, the coupling element 47 is opened, whereby the drive shaft 48 and the rotor 42 are decoupled.

[0073] In a further embodiment, the valve device 34 has a valve spool 56 movable between at least two positions 52, 54. In the first valve position 30, the valve spool 56 is arranged in a first of the positions 52 and in the second valve position 32, it is arranged in the second of the positions 54. The coupling device 50 is designed as an actuator 58 mechanically coupled to the valve spool 56, which is movable between at least two actuator positions 60, 62. The actuator 58 can be moved into a first of the actuator positions 60 by moving the valve spool 56 into the first position 52, whereby the rotor 42 and the drive shaft 48 are coupled via the coupling element 47. By moving the valve spool 56 to the second position 54, the actuator 58 can be moved to the second of the actuator positions 62, whereby the rotor 42 and the drive shaft 48 are decoupled.

[0074] In a further embodiment, a cooler 64 through which the fluid can flow and by means of which heat 66 can be dissipated from the fluid is arranged in a third line section 68 through which the fluid can flow and which is formed separately from the first and second line sections 14, 16. A first section 70 of the third line section 68 is fluidically connected to a cooler inlet 72 of the cooler 64. A second section 74 of the third line section 68 is fluidically connected to a cooler outlet 76 of the cooler 64. The third line section 68, in particular the second section 74, is fluidically connected to the first line section 14 via a connection point 78, so that the fluid flowing through the first line section 14 can be conveyed to the valve inlet 26, at least partially bypassing the cooler 64.

[0075] In a further embodiment, the braking device 10 has a hydraulic sump 80 that is fluidly connected or connectable to the fluid path 12, in which the fluid can be received or stored. The fluid is preferably oil, which is provided as transmission oil of a transmission of the motor vehicle, whereby the hydraulic sump 80 is a common sump for the transmission and the braking device 10, in particular the retarder 38 or the fluid path 12.

[0076] The third line section 68 is fluidically connected to a retarder outlet 82 of the retarder 38, whereby the fluid can be discharged from the retarder 38 via the retarder outlet 82, introduced into the third line section 68, in particular the first section 70, and fed to the cooler 64, whereby the fluid can be cooled. A branching point 84 is arranged in the third line section 68, in particular in the first section 70, via which branching point the third line section 68, in particular the first section 70, is fluidically connected to the hydraulic sump 80 via a first sump inlet 86.

[0077] In the third line section 68, in particular in the first section 70, a second check valve 88 through which the fluid can flow is arranged between the retarder outlet 82 and the cooler 64, in particular downstream of the branching point 84. The second check valve 88 is preferably designed to permit a flow of the fluid in a flow direction 90 from the retarder outlet 82 to the cooler 64, in particular to the branching point 84, and to prevent a flow of the fluid opposite to the flow direction 90 from the branching point 84 or from the cooler 64 or from the first sump inlet 86. The second check valve 88 has a spring element 92, whereby the second check valve 88 is designed as a spring-loaded check valve. A third check valve 94 through which the fluid can flow is arranged between the first sump inlet 86 and the branching point 84.The third check valve 94 is configured to permit a flow of fluid from the hydraulic sump 80 via the first sump inlet 86 through the third check valve 94 to the branching point 84 and to prevent an opposite flow of fluid from the branching point 84 to the first sump inlet 86.

[0078] In a further embodiment, the first line section 14 has a withdrawal point 96 arranged downstream of the connection point 78 in the flow direction 27 of the fluid flowing from the pump element 18 to the valve inlet 26. Via the withdrawal point 96, the first line section 14 is fluidly connected to a first line element 98 through which the fluid can flow. The first line element 98 is fluidly connected at one end to the withdrawal point 96 and at the other end to a control connection 100 of the valve device 34. As a result, the pump element 18, in particular the pump outlet 24, is fluidly connected to the control connection 100 of the valve device 34 via the withdrawal point 96, whereby the control connection 100 can be acted upon by the fluid by means of the pump element 18, whereby the valve device 34 can be moved from the second valve position 32 to the first valve position 30.This allows the closed coupling element 47 to be opened.

[0079] In a further embodiment, the fluid path 12 has a fourth line section 102, which is formed separately from the line sections 14, 16, 68 and through which the fluid can flow, via which the pump element 18 and the valve device 34 are fluidically connected, bypassing the first line section 14, the retarder 38, the valve inlet 26, the valve outlet 28, and the cooler 64. The pump element 18 is fluidically connected to the valve device 34 via a pump inlet 103 spaced apart from the pump outlet 24 and via the fourth line section 102.

[0080] In a further embodiment, the valve device 34 has a second valve inlet 104, which is spaced apart from the valve inlet 26 and fluidically connected to the fourth line section 102, and at least one second valve outlet 106, which is spaced apart from the valve outlet 28. The pump element 18 is fluidically connected to the second valve inlet 104 via the fourth line section 102, bypassing the first line section 14, the retarder 38, the valve inlet 26, the valve outlet 28, and the cooler 64. The valve device 34 has a second through-channel 108, which is spaced apart from the through-channel 36 and through which fluid can flow, and which is fluidically connectable to the second valve inlet 104 and the second valve outlet 106. The second valve outlet 106 is fluidically connected to the hydraulic sump 80 via a second sump inlet 110.In the second valve position 32, the second valve inlet 104 and the second valve outlet 106 are fluidically connected, whereby the fluid flowing through the fourth line section 102 can be introduced via the second valve inlet 104 into the second through-channel 108 and can thereby be introduced through the valve device 34 via the second valve outlet 106 via the second sump inlet 110 into the hydraulic sump 80. In the first valve position 30, the second valve inlet 104 is not fluidically connected to the second valve outlet 106, whereby the introduction of the fluid flowing through the fourth line section 102 via the valve device 34, in particular the second through-channel 108, via the second sump inlet 110 into the hydraulic sump 80 does not occur.

[0081] A fourth check valve 112 through which the fluid can flow is arranged in the fourth line section 102 between the pump element 18 and the second valve inlet 104. The fourth check valve 112 is designed to permit a flow of the fluid in a flow direction 114 from the pump element 18, in particular the pump inlet 103, to the second valve inlet 104 and to prevent a flow of the fluid opposite to the flow direction 114 from the second valve inlet 104 to the pump element 18, in particular the pump inlet 103. The fourth check valve 112 has a spring element 116, whereby the fourth check valve 112 is designed as a spring-loaded check valve.

[0082] In a further embodiment, a second connection point 118 is provided in the fourth line section 102, via which second connection point 118 the fluid flowing through the fourth line section 102 is fluidly connected to the hydraulic sump 80 via a third sump inlet 120, bypassing the retarder 38, the valve device 34, and the cooler 64. A fifth check valve 122 through which the fluid can flow is arranged between the third sump inlet 120 and the second connection point 118. The fifth check valve 122 is designed to allow a flow of fluid from the third sump inlet 120 to the second connection point 118 through the fifth check valve 122 and to prevent an opposite flow of fluid from the second connection point 118 to the third sump inlet 120.

[0083] In a further embodiment, the valve device 34 has a second control connection 124 spaced apart from the control connection 100. The second control connection 124 is fluidically connected to the fourth line section 102 via a third connection point 126, whereby the second control connection 124 can be acted upon by the fluid by means of the pump element 18 via the pump inlet 103 and the fourth line section 102. This means that the fluid flowing through the first line section 14 can, for example, be sucked in by the pump element 18 opposite to the flow direction 27, via the pump outlet 24 through the pump element 18 and introduced into the fourth line section 102 via the pump inlet 103, wherein the fluid flowing through the fourth line section 102 is supplied to the second control connection 124 by means of the pump element 18 via the third connection point 126.By applying the fluid or a fluid pressure to the second control port 124, the valve device 34 can be moved from the first valve position 30 to the second valve position 32. This allows the closed coupling element 47 to be opened.

[0084] In an operating mode of the braking device 10, particularly referred to as synchronization, the valve device 34 is initially in the second valve position 32. By means of the pump element 18, the fluid is sucked in or removed from the hydraulic sump 80 through the third sump inlet 120 and introduced into the first line section 14 via the second connection point 118 through the pump inlet 103 and the pump outlet 24. The fluid flowing through the first line section 14 is conveyed by the pump element 18 via the removal point 96 to the control connection 100, whereby the control connection 100 is subjected to the fluid or a pressure of the fluid. This is illustrated by arrows 129. As a result, the pressure of the fluid at the control connection 100 is particularly increased by means of the pump element 18, whereby the pressure of the fluid at the control connection 100 is greater than the pressure of the fluid at the second control connection 124.There is therefore a positive pressure difference between the control connections 100, 124. As a result of the positive pressure difference, the valve device 34 is moved from the second valve position 32 towards the first valve position 30. As a result, the valve spool 56 is moved from the second position 54 towards the first position 52, whereby the actuator 58, which is mechanically coupled to the valve spool 56, is moved from the second actuator position 62 towards the first actuator position 60. As a result, the respective rotational speeds of the drive shaft 48 and the rotor 42 are synchronized by means of the coupling element 47, in particular by means of locking synchronization. When the valve device 34 has been moved from the second position 32 to the first valve position 30, the rotational speeds of the drive shaft 48 and the rotor 42 are synchronized.This can be understood in particular to mean that the respective rotational speeds of the rotor 42 and the drive shaft 48 are identical.

[0085] In a further embodiment, the retarder 38 has a second retarder outlet 128 which is spaced apart from the retarder outlet 82 and which is fluidically connected to a second line element 130 through which the fluid can flow. The third line element 130 is fluidically connected to the hydraulic sump 80 via a fourth connection point 132 and a fourth sump inlet 134. A first throttle point 136 is arranged between the fourth connection point 132 and the fourth sump inlet 134. The fluid can be discharged from the retarder 38 via the second retarder outlet 128, introduced into the second line element 130, and introduced into the hydraulic sump 80 via the fourth connection point 132 and the first throttle point 136 via the fourth sump inlet 134. This allows pressure to be reduced in the retarder 38, or the retarder 38 can be vented.

[0086] In the Fig. 1 and the Fig. 2 In the embodiment shown, the retarder 38 has a third retarder outlet 138 through which the fluid can flow and which is spaced apart from the retarder outlet 82 and the second retarder outlet 128. The third retarder outlet 138 is fluidly connected to the hydraulic sump 80 via a second throttle point 140 and a fifth sump inlet 142. As a result, the fluid discharged from the retarder 38 via the third retarder outlet 138 can be introduced into the hydraulic sump 80 via the second throttle point 140 and the fifth sump inlet 142.

[0087] In a further embodiment, the valve device 34 has a third valve inlet 146 spaced apart from the valve inlet 26, the valve outlet 28, the second valve inlet 104, and the second valve outlet 106. In the second valve position 32, the third valve inlet 146 is fluidly connected to the second valve outlet 106, in particular via the second through-channel 108, whereby the fluid discharged from the retarder 38 via the second retarder outlet 128 can be introduced into the hydraulic sump 80 via the second line element 130, in particular the fourth connection point 132, the third valve inlet 146, the second valve outlet 106, and the second sump inlet 110.In the first valve position 30, the third valve inlet 146 is not fluidically connected to the second valve outlet 106, whereby the introduction of the fluid from the second line element 130 via the third valve inlet 146 and the second valve outlet 106 via the second sump access 110 into the hydraulic sump 80 is omitted.

[0088] During synchronization, it is preferably provided that, before the valve device 34 is moved in the direction of the first valve position 30 while the valve device 34 is in the second valve position 32, the fluid is discharged from the retarder 38 via the second retarder outlet 128 to reduce the pressure in the retarder 38, is introduced into the second line element 130 and is introduced into the hydraulic sump 80 via the fourth connection point 132, the third valve inlet 146, the second valve outlet 106 and the second sump inlet 110.

[0089] The synchronization can, for example, be followed by an operating mode of the braking device 10, particularly referred to as braking mode. In braking mode, the fluid is sucked in from the fourth line section 102 by means of the pump element 18, whereby the fluid is withdrawn from the hydraulic sump via the third sump inlet 120, introduced into the fourth line section 102, and flows through the pump element 18 in the first flow direction 127 via the second connection point 118. The fluid flows via the pump inlet 103 and the pump outlet 24 into the first line section 14. This is illustrated by the arrows 129. As a result, a fluid pressure is built up in the first line section 14 by means of the pump element 18, which pressure is preferably greater than during synchronization.Because the valve device 34 is in the first valve position 30, the fluid flowing through the first line section 14 can be introduced via the valve inlet 26, through the through-channel 36, and via the valve outlet 28 into the second line section 16, and can thus be supplied to the retarder 38 via the retarder inlet 44. The fluid is thus introduced into the retarder 38. As a result, the pressure of the fluid in the retarder 38 can be particularly increased, in particular compared to synchronization. In particular, as a result of the particularly high pressure of the fluid in the retarder 38, the rotor 42 is braked by the fluid, whereby the drive shaft 48 is decelerated as a result of the mechanical coupling of the rotor 42 to the drive shaft 48 via the closed coupling element 47. As a result, the motor vehicle can be braked.

[0090] In braking mode, the fluid is discharged from the retarder 38 via the retarder outlet 82 and introduced into the third line section 68, passed through the cooler 64, and reintroduced into the first line section 14 via the connection point 78. This is illustrated by arrows 147. This allows the fluid to be cooled in braking mode.

[0091] In the third line section 68, in particular in the first section 70, a temperature sensor 148 is arranged between the branching point 84 and the cooler 64. The temperature sensor 148 is designed to detect a temperature of the fluid flowing through the third line section 68. For example, it can be provided that if, in braking mode, the temperature of the fluid detected by the temperature sensor 148 exceeds a predetermined temperature threshold, a braking torque applied to the drive shaft 48 by the braking device 10, in particular the retarder 38, is limited. This can be achieved, for example, by using the pump element 18 to particularly reduce a mass flow of the fluid conveyed from the fourth line section 102 into the first line section 14.In the first line section 14, in particular between the connection point 78 and the withdrawal point 96, a pressure sensor 150 is arranged, by means of which a pressure of the fluid flowing through the first line section 14 can be detected.

[0092] An operating mode of the braking device 10, particularly referred to as standby mode, can in particular follow the braking mode or the synchronization. In this case, the pressure of the fluid is particularly reduced by means of the pump element 18 in the first line section 14, in particular compared to the braking mode. For example, the mass flow of the fluid is particularly reduced, wherein the pump element 18 can be decelerated to a standstill. In this case, it is provided that no pressure build-up occurs in the fourth line section 102, in particular in the second control connection 124, in particular compared to the braking mode. As a result, the synchronization remains active, i.e. the rotational speeds of the drive shaft 48 and the rotor 42 are synchronous with one another, wherein the braking of the drive shaft 48 by the rotor 42 is omitted.

[0093] An operating mode of the braking device 10, particularly referred to as shutdown, can, for example, follow the standby mode or the braking mode. In this case, the fluid is sucked from the hydraulic sump 80 via the first sump inlet 86 by means of the pump element 18 and thereby introduced into the third line section 68 via the branching point 84. As a result of the suction, the fluid flowing through the third line section 68 is guided through the cooler 64 and introduced into the pump element 18 via the pump outlet 24. It is then discharged from the pump element 18 via the pump inlet 103 and introduced into the fourth line section 102. The fluid thus flows through the pump element 18 in a second flow direction 152 opposite the first flow direction 127.The fluid flowing through the fourth line section 102 is fed to the second control port 124 by means of the pump element 18 via the fourth check valve 112 and the third connection point 126. As a result, the second control port 124 is subjected to the fluid or the pressure of the fluid. As a result of the application, the pressure of the fluid at the second control port 124 is greater than at the control port 100. Thus, a negative pressure difference exists between the control ports 100, 124. As a result of the application or the negative pressure difference, the valve device 34 is moved from the first valve position 30 toward the second valve position 32. As a result, the closed coupling element 47 is opened, whereby the drive shaft 48 and the rotor 42 are decoupled, so that the deceleration of the drive shaft 48 by the rotor 42 is eliminated.By opening the clutch element 47, the synchronization is deactivated, i.e. the speeds of the drive shaft 48 and the rotor 42 can be different from each other.

[0094] In the shutdown mode, the valve device 34 is preferably in an intermediate position 154 different from the first and second valve positions 30, 32, or the valve device 34 is moved into the intermediate position 154 in the shutdown mode. Fig. 3 shows a schematic partial sectional view of the braking device 10, wherein the valve device 34 is in the intermediate position 154. The valve device 34 is in the intermediate position 154 between the first and second valve positions 30, 32, which can be understood in particular to mean that the valve spool 56 is arranged between the first and second positions 52, 54. In the intermediate position 154, the respective valve inlets 26, 106, 146 are not fluidically connected to the respective valve outlets 28, 106, as a result of which the fluid cannot flow through the valve device 34, in particular the first and second through-channels 36, 108. Alternatively, in the shutdown mode, the valve device 34 can be moved into the second valve position 32 as a result of the application or the negative pressure difference of the first valve position 30.

[0095] An operating mode, particularly referred to as cooling mode, can, for example, follow shutdown. In this case, the pressure in the fourth line section 102, in particular at the second control connection 124, is increased by means of the pump element 18, as a result of which the valve device 34 is moved into the second valve position 32. By means of the pump element 18, the fluid is sucked in from the hydraulic sump 80 via the first sump inlet 86 and introduced into the third line section 68. As a result of the suction, the fluid is passed through the cooler 64, as a result of which the fluid can be cooled. The fluid then flows through the pump element 18 in the second flow direction 152 via the connection point 78 and the first line section 14. The fluid is thereby introduced into the fourth line section 102 and supplied to the second valve inlet 104 by means of the pump element 14 via the third connection point 126.This is illustrated by arrows 155. Because the valve device 34 is in the second valve position 32, the fluid can then be introduced into the hydraulic sump 80 via the second valve inlet 104, through the second through-channel 108, and via the second valve outlet 106 via the second sump inlet 110. Thus, the fluid can be withdrawn from the transmission, for example, and fed from the hydraulic sump 80 to the fluid path 12 via the first sump inlet 86, cooled by the cooler 64, and then returned to the transmission via the second sump inlet 110 and the hydraulic sump 80.

[0096] In a further embodiment, the braking device has a shut-off device 174. The shut-off device 174 is designed to particularly increase the pressure of the fluid in the fourth line section 102, in particular particularly quickly, whereby the second control connection 124 can be subjected to the pressure of the fluid, whereby the valve device 34 is moved, in particular particularly quickly, from the first valve position 30 to the second valve position 32.

[0097] In the Fig. 1-3 In the embodiment shown, the shut-off device 174 is designed as a hydraulic shut-off device 176. The hydraulic shut-off device 176 has an electrical switching valve 177 with an inlet 178 through which the fluid can flow and an outlet 180 through which the fluid can flow, which is or can be connected fluidically to the second control connection 124. The electrical switching valve 177 is movable between at least two positions, wherein in a first of the positions the inlet 178 and the outlet 180 are fluidically connected, whereby the fluid can flow from the inlet 178 through the electrical switching valve 177 to the outlet 180, and in the second position the inlet 178 is not fluidically connected to the outlet 180, whereby the fluid does not flow through the electrical switching valve. Fig. 1-3 the switching valve 177 of the hydraulic shut-off device 176 is shown in the second position.

[0098] The inlet 178 is fluidically connected to the third retarder outlet 138 via the third line element 130. In an operating mode referred to in particular as rapid shutdown, which can follow the braking mode, for example, the electrical switching valve 177 of the hydraulic shutdown device 176 can be moved from the second position to the first position. As a result, the fluid discharged from the retarder 38 via the third retarder outlet 138 can be guided through the electrical switching valve 177, in particular via the inlet 178 and the outlet 180, introduced into the fourth line section 102 and supplied to the second control port 124, whereby the pressure in the fourth line section 102, in particular in the second control port 124, can be particularly increased. For this purpose, the outlet 180 is fluidically connected to the fourth line section 102 via a fifth connection point 181.In particular, because the pressure at the second control port 124 is then greater than the pressure of the fluid at the first control port 100, the valve device 34 can be moved from the first valve position 30 to the second valve position 32. This opens the coupling element 47.

[0099] Alternatively, the shutdown device 176 can be designed as a pneumatic shutdown device 182. Fig. 4 shows a schematic partial sectional view of the braking device 10, wherein the valve device 34 is in the second valve position 32 and the shut-off device 176 is designed as a pneumatic shut-off device 182. The pneumatic shut-off device 182 has an electrical switching valve 183, which is movable between at least two positions and comprises an inlet 184 through which air can flow and an outlet 186 through which air can flow and spaced from the inlet. The inlet 184 is fluidly connected to a compressed air reservoir 188, by means of which the pneumatic shut-off device 182, in particular the inlet 184, can be supplied with compressed air. The pneumatic shut-off device 182 has a pneumatic cylinder 190, in which a piston element 192 is accommodated for translational movement.The piston element 192 can be moved translationally relative to a cylinder wall of the pneumatic cylinder 190 between a first piston position and a second piston position. The cylinder 190 has an opening 194 through which air or compressed air can flow, which is fluidically connected to the outlet 186. The piston element 192 is mechanically connected or coupled to the valve device 34, in particular the valve spool 56 and / or the coupling device 50. In the . Fig. 4 the electrical switching valve 183 of the pneumatic shut-off device 182 is shown in the second position.

[0100] In a first position of the electric switching valve 183, the inlet 184 is fluidically connected to the outlet 186, whereby the air from the compressed air reservoir 188 can be introduced via the inlet 184, through the electric switching valve 183, the outlet 186, and through the opening 194 into the cylinder 190, whereby the piston element 192 is pressurized with compressed air. In the second position, the inlet 184 is not fluidically connected to the outlet 186, whereby the electric switching valve 183 cannot be flowed through by compressed air and the piston element 192 is not pressurized with compressed air. By pressurizing the piston element 192 with compressed air, the piston element 192 is moved from the first piston position to the second piston position.Because the piston element 192 and the valve device 34 are mechanically coupled, when the piston element 192 is moved into the second piston position, the valve device is moved from the first valve position 30 to the second valve position 32. In the . Fig. 4 the piston element 192 is in the second piston position.

[0101] The pneumatic shut-off device 182 has a second outlet 196 through which air can flow, spaced apart from the inlet 184 and the outlet 186, and fluidically connected to a venting device 198. In the second position of the electric switching valve 183, the outlet 186 is fluidically connected to the second outlet 196, whereby the air can be discharged from the cylinder 190 and fed to the venting device 198 via the outlet 186 and the second outlet 196. This allows the cylinder 190 to be vented by means of the venting device 198.

[0102] The shutdown device 174, in particular the hydraulic and pneumatic shutdown devices 176, 182, has at least one spring element 200, by means of which the shutdown device 174 can be moved from the second position to the first position.

[0103] In the in the in the Fig. 1-3 In the exemplary embodiment shown, a sixth check valve 202 through which the fluid can flow is arranged in the third line element 130 between the third retarder outlet 138 and the fourth connection point 132. The sixth check valve 202 is designed to allow a flow of the fluid from the third retarder outlet 128 and / or from the inlet 178 through the sixth check valve 202 to the fourth connection point 132 and to prevent an opposite flow of the fluid from the fourth connection point 132 to the third retarder outlet 128 and / or to the inlet 178.

[0104] The braking device has a displacement sensor 204 which is designed to detect the respective valve position 30, 32 and / or the respective position 52, 54 and / or the respective actuator position 60, 62. List of reference symbols

[0105] 10 Brake device 12 Fluid path 14 First line section 16 Second line section 18 Pump element 20 Electric motor 24 Pump outlet 26 Valve inlet 27 Flow direction 28 Valve outlet 30 First valve position 32 Second valve position 34 Valve device 36 Through-channel 38 Retarder 40 Stator 42 Rotor 44 Retarder inlet 45 First check valve 46 Flow direction 47 Coupling element 48 Drive shaft 50 Coupling device 52 First position 54 Second position 56 Valve spool 58 Actuator 60 First actuator position 62 Second actuator position 64 Radiator 66 Heat 68 Third line section 70 First section 72 Radiator inlet 74 Second section 76Cooler outlet 78Connection point 80Hydraulic sump 82Retarder outlet 84Branching point 86First sump inlet 88Second check valve 90Flow direction 92Spring element 94Third check valve 96Tapping point 98First line element 100Control connection 102Fourth line section 103Pump inlet 104Second valve inlet 106Second valve outlet108 Second through-channel 110 Second sump inlet 112 Fourth check valve 114 Flow direction 116 Spring element 118 Second connection point 120 Third sump inlet 122 Fifth check valve 124 Second control connection 126 Third connection point 127 First flow direction 128 Second retarder outlet 129 Arrows 130 Second line element 132 Fourth connection point 134 Fourth sump inlet 136 First throttle point 138 Third retarder outlet 140 Second throttle point 142 Fifth sump inlet 146 Third valve inlet 147 Arrows 148 Temperature sensor 150 Pressure sensor 152 Second flow direction 154 Intermediate position 155 Arrows 174 Shutdown device 176 Hydraulic shut-off device 177 Switching valve 178 Inlet 180 Outlet 181 Fifth connection point 182 Pneumatic shut-off device 183 Switching valve 184 Inlet 186 Outlet 188 Compressed air reservoir 190 Cylinder 192 Piston element 194 Opening 196 Second outlet 198 Venting device 200 Spring element 202 Sixth check valve 204 Position sensor

Claims

1. A braking device (10) for a motor vehicle, comprising a fluid path (12) through which a fluid can flow and which has at least two conduit sections (14, 16) and in which at last one pump element (18) for conveying the fluid through the fluid path (12), and at least one valve device (34) fluidly connected to the pump element (18) via the valve inlet (26) by means of a first conduit section (14) of the conduit sections (14, 16) and through which the fluid can flow and which has at least one valve inlet (26) and one valve outlet (28) and which can be moved between at least two valve positions (30, 32) is disposed, comprising a retarder (38) having a stator (40), a rotor (42) configured separately from the stator (40), and retarder inlet (44), via which the retarder (38) is fluidly connected to the valve device (34) by means of a second conduit section (16) of the conduit sections (14, 16) via the valve outlet (28), wherein, in a first one of the valve positions (30), the valve inlet (26) is fluidly connected to the valve outlet (28), whereby the fluid flowing through the first conduit section (14) can be delivered to the retarder inlet (44) via the second conduit element (16), and, in the second valve position (32), the valve inlet (26) is not fluidly connected to the valve outlet (28), characterised by at least one clutch element (47), via which the rotor (42) can be coupled with a drive shaft (48) of the motor vehicle and can be decoupled from the drive shaft (48), and a coupling device (50), by means of which the rotor (42) and the drive shaft (48) can be coupled via the clutch element (47) by moving the valve device (34) into the first valve positon (30), and can be decoupled by moving the valve device (34) into the second valve position (32).

2. The braking device (10) according to claim 1, characterised in that the valve device (34) has a valve spool (56) which can be moved between at least two positions (52, 54) and which, in the first valve position (30), is disposed in a first of the positions (52) and which, in the second valve position, is disposed in the second of the positions (54), and the coupling device (50) is configured as an actuator (58) mechanically coupled with the valve spool (56) and which can be moved between at least two actuator positions (60, 62), wherein the actuator (58) can be moved into a first one of the actuator positions (60) by moving the valve spool (56) into the first position (52), whereby the rotor (42) and the drive shaft (48) are coupled via the coupling element (47), and which can be moved into a second one of the actuator positions (62) by moving the valve spool (56) into the second position (54), whereby the rotor (42) and the drive shaft (48) are decoupled.

3. The braking device (10) according to claim 1 or 2, characterised by at least one cooler (64) disposed in the fluid path (12) and through which the fluid can flow and by means of which heat (66) can be removed from the fluid, and / or a hydraulic sump (80) which can be fluidly connected to the fluid path (12).

4. The braking device (10) according to claim 3, characterised in that the cooler (64) is disposed in a third conduit section (68) of the fluid path (12) configured separately from the first and the second conduit section (14,16), wherein the third conduit section (68) is fluidly connected to the first conduit section (14) via a connection point (78), so that the fluid flowing through the first conduit rout (14) can be conveyed to the valve inlet (26) while bypassing the cooler (64).

5. The braking device (10) according to claim 4, characterised in that the third conduit section (68) is fluidly connected to a retarder outlet (82) of the retarder, whereby the fluid can be removed from the retarder (38) via the retarder outlet (82) and delivered to the cooler (64), wherein a branching point (84), via which the cooler (64) is fluidly connected to the hydraulic sump (80) while bypassing the pump element (18), the retarder (38), and the valve device (34), is disposed in the third conduit section (68).

6. The braking device (10) according to one of the preceding claims, characterised in that the first conduit section (14) has a draw-off point (96), via which the pump element (18) is fluidly connected to a control port (100) of the valve device (34), whereby the control port (100) can be supplied with the fluid by means of the pump element (18), whereby the valve device (134) can be moved from the second valve position (32) to the first valve position (30).

7. The braking device (10) according to one of the preceding claims, characterised in that the fluid path (12) includes a fourth conduit section (102) configured separately from the conduit sections (14, 16, 68) and through which the fluid can flow, and via which the pump element (18) and the valve device (134) are fluidly connected while bypassing the first conduit section (14), the retarder (38), the valve inlet (26), and the valve outlet (28).

8. The braking device (10) according to claim 7, characterised in that the valve device (34) has at least one second valve inlet (104) spaced apart from the valve inlet (26) and fluidly connected to the fourth conduit section (102), and at least one second valve outlet (106) spaced apart from the valve outlet (28) and fluidly connected to the hydraulic sump (80), wherein, in the second valve position (32), the fluid flowing through the fourth conduit section (102) can be introduced into the hydraulic sump (80) via the second valve outlet (106), through the valve device (34) and via the second valve outlet (106).

9. The braking device (10) according to claim 7 or 8, characterised by a second connection point (118) disposed in the fourth conduit section (102) and via which the fluid flowing through the fourth conduit section (102) is fluidly connected to the hydraulic sump (80) while bypassing the retarder (38) and the valve device (34).

10. The braking device (10) according to one of claims 7 to 9, characterised in that the valve device (34) has at least one second control port (124) spaced apart from the control port (100) and fluidly connected to the fourth conduit section (102) and which can be supplied with the fluid by means of the pump element (18) via the fourth conduit section (102), whereby the valve device (34) can be moved from the first position (30) to the second position (32).