Brake device, in particular for electrically driven motor vehicles
A brake device for a motor vehicle with two axles in which at least one axle has an electric traction motor for driving and braking at least one wheel arranged on an axle, and in which energy can be recovered via the traction motor during braking, each wheel having a wheel brake. The brake device includes a pressure supply having an electric motor-driven pump in the form of a piston-cylinder unit or a rotary pump, which can both build up pressure and reduce pressure, and which is part of a pressure supply device. An open-loop and closed-loop control device controls the traction motor and components of the pressure supply device such that a braking deceleration can be set by closed-loop control individually for each brake circuit, each axle or wheel brakes of an axle, with different braking torques at the respective axles or wheel brakes of an axle.
1. A driving dynamics system comprising:
a first axle and a second axle, each including one or more wheels;
at least one electric traction motor for driving and braking at least one of the wheels, wherein energy is enabled to be recovered by means of the traction motor during braking;
hydraulic wheel brakes arranged to brake respective ones of the wheels;
a pressure supply device with pressure supply, comprising a piston-cylinder unit with a piston driven by an electric motor or a rotary pump, wherein the pressure supply is designed to both build up pressure and to reduce pressure;
a central software module configured for a brake management that controls the at least one electric traction motor and the pressure supply device such that, by the interaction of the pressure supply device and the at least one electric traction motor, a braking deceleration is set by closed-loop control individually for each axle and/or each wheel brake, so that with simultaneous recuperation, electric braking force distribution is implemented between the first and the second axle;
a first brake circuit connected with the pressure supply by a first connection line to facilitate supplying pressure;
at least one first switching valve arranged to selectively close and open the first connection line;
a second brake circuit connected with the pressure supply by a second connection line to facilitate supplying pressure; and
at least one second switching valve arranged to selectively close and open the second connection line;
wherein the pressure supply is adapted to perform a pre-pressure control, in which a first pressure is set in the first brake circuit using the at least one first switching valve opened, and wherein a second pressure is set in the second brake circuit simultaneously or semi-simultaneously.
2. The driving dynamics system as claimed in claim 1 , further comprising a first housing and a second housing, wherein the pressure supply device is disposed in the first housing, and wherein an actuating unit, comprising an electric pedal or a hydraulic actuating unit with a brake pedal and a travel simulator, is disposed in the second housing.
3. The driving dynamics system as claimed in claim 2 , wherein the pressure supply device comprises two further connections, which serve for connection to the actuating unit, and wherein, by means of a build-up of pressure by the pressure supply device, a diagnosis of the actuating unit is performed in an event of failure of seals of pistons of the actuating unit.
4. The driving dynamics system as claimed in claim 2 , wherein a braking force at the axles is generated by interaction of pressure of the pressure supply device and/or of the actuating unit with a braking torque of the at least one electric traction motor, wherein an open-loop and closed-loop control device is provided to control the pressure supply device and/or the actuating unit, along with the at least one electric traction motor, such that a braking deceleration at vehicle speeds <120 kph is implemented more than ⅔ by means of one or more of the at least one electric traction motor, to enable kinetic energy of the vehicle to be converted into electrical energy and stored.
5. The driving dynamics system as claimed in claim 1 , wherein driving dynamics control actuators are provided for brakes, steering, and damping in order to optimize driving dynamics.
6. The driving dynamics system as claimed in claim 1 , further comprising one or two open-loop and closed-loop control device(s) provided for the pressure supply device and/or at least one open-loop and closed-loop control device provided for the at least one traction motor, which open-loop and closed-loop control device(s) communicates or communicate bidirectionally via redundant signal lines with a superordinate open-loop and closed-loop control device and/or communicate with one another.
7. The driving dynamics system as claimed in claim 1 , wherein a pressure is reduced and/or built up by means of the pressure supply by forward and backward movement of the piston of the pressure supply, wherein pressure is transmitted via the first connection line via the first switching valve to the first brake circuit and via a floating piston and the second switching valve into the second brake circuit, wherein the first and second switching valves are of normally-open design, whereby a previously implemented brake-circuit-specific simultaneous or partially simultaneous pressure profile control is realized by way of piston pressure control (PPC) of the piston of the pressure supply, supplemented by pulse-width modulation (PWM) control or current control of at least one of the first or second switching valves.
8. The driving dynamics system as claimed in claim 1 , wherein the first and second switching valves are of normally-open design.
9. The driving dynamics system as claimed in claim 1 , wherein an anti-lock braking/electronic stability control (ABS/ESP) unit is interconnected between the pressure supply device and the first and second brake circuits, wherein the ABS/ESP unit is connected by way of its inlets to the first and second connecting lines.
10. A driverless vehicle comprising the driving dynamics system as claimed in claim 1 , wherein the driving dynamics system is operated purely in an autonomous driving (AD-Ctrl) operation.
11. A racing vehicle comprising the driving dynamics system as claimed in claim 1 , wherein dynamic axle-specific braking torque control is performed in the context of electronic brake force distribution (EBV) optimization and simultaneous recuperation by means of the at least one electric traction motor at one or two of the axles.
12. An electric vehicle comprising the driving dynamics system as claimed in claim 1 .
13. The driving dynamics system as claimed in claim 1 , wherein the first pressure is larger than the second pressure.