Redundant power supply for an electromechanical braking system

Abstract

Electromechanical brake actuator (4) for an electromechanical braking system (1), wherein the brake actuator (4) comprises: - a supply terminal (4a) configured to receive electrical energy from a power supply (6); and - a control terminal (4b) configured to receive electrical control signals when the brake actuator (4) is supplied via the supply terminal (4a) in order to actuate a brake; wherein the brake actuator (4) is configured to be operated by energy supplied to the control terminal (4b) when no or insufficient energy is supplied to the supply terminal (4a) and / or when a corresponding control signal is supplied to the brake actuator (4) enabling operation by energy supplied to the control terminal (4b).

Description

The present invention relates to an electromechanical brake actuator, an electromechanical braking system and a vehicle with such a brake actuator or such a braking system. Modern vehicles with pneumatic braking systems must still be able to achieve a legally specified residual braking effect in the event of a complete brake circuit failure. This can lead to problems, especially with an unloaded tractor unit or without a trailer: If the brake circuit on the front axle fails, the minimum deceleration specified by law cannot always be guaranteed solely by the brakes on the rear axle, as the front axle is unbraked. Therefore, modern tractor units have an additional valve that diverts brake control pressure – at least partially – from the rear axle to a brake actuator on the front axle. This additional braking force at one wheel on the front axle ensures the required residual deceleration. German patent application DE 10 2011 121 580 A1 discloses a brake actuator for an electromechanical braking system, comprising a supply terminal that receives electrical energy from a power supply and a control terminal that receives electrical control signals. The brake actuator is operated by energy supplied to the control terminal when no or insufficient energy is supplied to the supply terminal and / or when a corresponding control signal is supplied to the brake actuator, enabling operation by means of energy supplied to the control terminal. German patent application DE 2006 032 279 A1 discloses an electromechanical braking system comprising a first electromechanical brake actuator, a first power supply that provides electrical energy to the first brake actuator, and a second power supply. The braking system supplies the first brake actuator with electrical energy from the second power supply when the first power supply has failed and / or when a corresponding control signal triggers a switch from the first power supply to the second power supply. Since no compressed air is available in an electromechanical braking system, the object of the present invention is to provide a way to ensure a redundant power supply for individual brake actuators. This task is solved by the subject matter of independent claims. Advantageous further developments are the subject matter of dependent claims. According to the invention, an electromechanical brake actuator is provided for an electromechanical braking system, wherein the brake actuator has: - a supply connection configured to receive electrical energy from a power supply; and - a control connection configured to receive electrical control signals; wherein the brake actuator is configured to be operated with energy supplied to the control connection. Preferably, the brake actuator is designed to be operated with energy supplied to the control terminal when no or insufficient energy is supplied to the supply terminal and / or when a corresponding control signal is supplied to the brake actuator, preferably to the control terminal, which enables operation by means of energy supplied to the control terminal. Such a brake actuator is preferably equipped with an automatic fallback mechanism designed to use the energy supplied to the control terminal to operate the actuator as soon as no energy is supplied to the power supply terminal. The maximum power supplied to the control terminal can also be lower than that supplied to the power supply terminal. In particular, it can be supplied in such a way as to meet the legally required minimum braking performance. The fallback mechanism is preferably implemented by an electrical circuit or an electromechanical mechanism that reacts to a power supply failure and / or to the corresponding control signal. The energy supply is described in more detail below as an example of a first or second energy supply. As a further aspect of the invention, an electromechanical braking system, in particular for a vehicle with at least two axles having wheels, is provided, wherein the braking system comprises: - a first electromechanical brake actuator; - a first power supply configured to provide electrical energy for the first brake actuator; and - a second power supply, wherein the braking system is configured to supply the first brake actuator with electrical energy from the second power supply. Preferably, the braking system is designed to supply the first brake actuator with electrical energy from the second energy supply, e.g. a redundant energy storage device, when the first energy supply has failed and / or when a corresponding control signal triggers a switch from the first energy supply to the second energy supply. The failure of the primary power supply can mean that no energy at all is supplied to the primary brake actuator. However, it can also mean that the power supplied to the primary brake actuator is no longer sufficient to operate it. The method according to the invention thus has the advantage that the first brake actuator is redundantly supplied with energy from the second energy supply. The primary energy supply can include an energy storage device, particularly a battery. Alternatively or additionally, the primary energy supply can include a fuel cell or the vehicle's drive system, such as a conventional or hybrid drive. The second energy supply can include an energy storage device, in particular a battery. Alternatively or additionally, the second energy supply can include a fuel cell, or the vehicle's drive system, such as a conventional or hybrid drive. Preferably, the braking system comprises a second electromechanical brake actuator, wherein the second power supply is particularly preferably configured to provide energy for the second brake actuator. Alternatively or additionally, the second power supply includes a redundant power supply, in particular a redundant energy storage device. This enables the power supply to the first brake actuator if the power supply from the first power supply is insufficient. The redundant power supply does not necessarily have to be designed to supply the second brake actuator, but can instead supply other vehicle consumers, or be designed exclusively to supply the first brake actuator. Preferably, the braking system is designed to discontinue the power supply to the second brake actuator and / or other consumers from the second power supply in the event of a failure of the first power supply, and instead supply power exclusively to the first brake actuator. This is particularly advantageous if the braking effect achievable with the first brake actuator is expected to be greater than that achievable with the second brake actuator. Furthermore, this design is suitable if the second power supply can only supply a limited number of brake actuators, thus necessitating a prioritization of the brake actuators based on the achievable braking effect. The first brake actuator and / or the second brake actuator preferably comprise more than one brake actuator. Preferably, the first brake actuator and the second brake actuator are assigned to different wheels and / or different axles. This ensures that the axle on which the first brake actuator is located, or the wheels to which the first brake actuator is assigned, can still generate a braking effect even if the first power supply fails. Preferably, the first brake actuator is assigned to a front axle or a wheel on the front axle of the vehicle. This approach addresses, in particular, the problem described above, namely that a semi-trailer truck exhibits poor braking performance when unloaded or without a trailer if the front axle cannot be braked. This ensures that at least one brake actuator is supplied with energy from the second power supply, thus enabling braking at the front axle. It is especially preferred that all brake actuators on the front axle are supplied with energy from the second power supply. Preferably, a separate connection is provided, designed to directly supply the first brake actuator with energy from the second power supply. For this purpose, the brake system preferably includes an electrical conductor, which is particularly preferably designed to transmit a maximum power to the first brake actuator, specifically one that corresponds to the maximum power of the first power supply. However, since a minimum braking performance requirement is stipulated by law, the electrical conductor can preferably be dimensioned accordingly smaller, so that the energy transmitted to the first brake actuator is only sufficient to meet this minimum requirement. Preferably, the separate connection supplies all brake actuators of one axle of the vehicle. Preferably, the braking system is configured to supply the first brake actuator with energy from the second power supply via another device of the vehicle, in particular via a device of the braking system, such as a control unit. It is possible that, in this configuration, a lower maximum power is supplied to the first brake actuator than by the first power supply. This is limited by the maximum permissible power of the device or the lines provided. If the device is a control unit, the existing control line, preferably connected to a control terminal of the first brake actuator, can be used to transmit the electrical energy to the first brake actuator. However, preferably a maximum power is supplied to the brake actuator in order to meet a legally mandated minimum braking performance requirement.However, it is also conceivable to transmit a higher maximum power to the first brake actuator by appropriately designing the device or the lines, i.e., for example, the control unit and the control line, which corresponds in particular to the maximum power of the first power supply. Preferably, the braking system is designed to supply the first brake actuator with energy from the second power supply at a lower power output than when supplied with energy from the first power supply. This allows a smaller connecting line to be used in order to meet a minimum braking performance requirement. Preferably, the first brake actuator comprises a brake actuator according to the invention as described above, wherein the supply connection is connected to the first power supply, and the control connection is connected to a control unit of the brake system. The brake system is particularly configured to supply electrical energy from the control unit to the control connection for operating the first brake actuator when the first power supply has failed and / or when a corresponding control signal has been supplied to the first brake actuator, enabling operation by means of energy supplied to the control connection. Normally, the first brake actuator is supplied with energy from the first power supply and is controlled according to the control signals supplied to the control connection. If the first power supply fails, the brake actuator switches between the supply and control inputs, so that it now receives control signals or...Power supplied to the control port is used to operate the brake actuator. As a further aspect of the invention, a vehicle with an electromechanical braking system as described above, and / or a brake actuator as described above, is provided, wherein the vehicle is preferably designed as a passenger car, truck, commercial vehicle, towing vehicle, in particular as a semi-trailer tractor, as a trailer or as a combination of towing vehicle and trailer. The invention is described below with reference to preferred embodiments and the accompanying drawings. Fig. 1 shows a brake actuator according to the invention, Fig. 2 shows a first embodiment of a brake system according to the invention, and Fig. 3 shows a second embodiment of a brake system according to the invention. Fig. 1 shows a brake actuator according to the invention. An electromechanical brake actuator 4 is shown. This actuator has a supply terminal 4a through which electrical energy from a power supply can be supplied to the brake actuator 4 to operate it. Furthermore, the brake actuator 4 has a control terminal 4b through which electrical control signals can be supplied to the brake actuator 4 to actuate it. Finally, the brake actuator 4 has an actuating element 4c. The brake actuator 4 is designed to move the actuating element 4c accordingly in response to a control signal supplied to the brake actuator 4 via the control terminal 4b, thereby actuating a brake. The brake actuator 4 further comprises a fallback mechanism (not shown) configured to switch between the supply terminal 4a and the control terminal 4b when the supply terminal 4a is no longer supplied with electrical energy or power and / or when a corresponding control signal is applied to the brake actuator 4. The brake actuator 4 can then use electrical energy or power supplied to the control terminal 4b for operation. The fallback mechanism can be implemented by an electrical circuit or by an electromechanical mechanism that responds to the failure of the power supply connected to the supply terminal 4a. Fig. 2 shows a first embodiment of a braking system according to the invention. An electromechanical braking system 1 for a vehicle is shown. The vehicle has two axles 2, 3 with wheels (not shown), with a first electromechanical brake actuator 4 assigned to axle 2 and a second electromechanical brake actuator 5 assigned to axle 3. The brake actuators 4, 5 are configured to actuate brakes (not shown) provided on axles 2, 3. The braking system 1 has a first power supply 6 configured to supply the first brake actuator 4 with electrical energy. Furthermore, a second power supply 7 of the braking system 1 is shown, configured to supply the second brake actuator 5 with electrical energy. All connections for energy and power transmission are shown here as arrows. The first energy supply 6 can include an energy storage device. Alternatively or additionally, the first energy supply 6 can include a fuel cell or a vehicle drive system, such as a conventional or hybrid drive. If the first power supply 6 fails, the braking system 1 is designed to draw energy from the second power supply 7 and supply it to the first brake actuator 4. In this way, the first brake actuator 4 can continue to operate. The switch from the first power supply 6 to the second power supply 7 can also be controlled by a corresponding control signal. In a specific embodiment, if the first power supply 6 fails, the power supply to the second brake actuator 5 is discontinued by the second power supply 7, and only the first brake actuator 4 is supplied by the second power supply 7. This is particularly advantageous if the first brake actuator 4 can achieve a significantly better braking effect on the vehicle compared to the braking effect of the second brake actuator 5. Thus, the power distribution from the second power supply 7 is prioritized. This is especially useful if the second power supply 7 is designed in such a way that it cannot provide enough energy or power to operate both brake actuators 4 and 5. The first brake actuator 4 can, for example, comprise a brake actuator 4 as shown in Fig. 1. Fig. 3 shows a second embodiment of a braking system according to the invention. This embodiment essentially corresponds to the embodiment shown in Fig. 2. Therefore, only the differences will be discussed below, and otherwise reference is made to the above explanations regarding Fig. 2. In comparison to Fig. 2, a device 8 is shown here, wherein the braking system 1 is designed to supply the energy from the second power supply 7 to the first brake actuator 4 via this device 8. The device 8 can be a control unit of the brake system 1, which, when the first power supply 6 is active, controls the first brake actuator 4 by means of electrical control signals. If the first power supply 6 fails or a switch to the second power supply 7 is triggered by a corresponding control signal, the first brake actuator 4 can be powered by energy from the second power supply 7 by supplying this energy to the device 8 and from there via the control line to the first brake actuator 4. The first brake actuator 4 is designed to react to the failure of the first power supply 6 and / or a corresponding control signal and to use the energy or power supplied to the first brake actuator 4 by the device 8 for its operation. For example, the first brake actuator 4 comprises a brake actuator 4 according to Fig. 1, wherein there is a connection from the first power supply 6 to the supply terminal 4a and a connection from the device 8 to the control terminal 4b. In the embodiments shown in Fig. 2 and Fig. 3, for example, axle 2 is designed as the front axle of the vehicle. REFERENCE MARK LIST 1 Electromechanical braking system 2 Axle 3 Axle 4 First brake actuator 4a Supply connection 4b Control connection 4c Actuating element 5 Second brake actuator 6 First power supply 7 Second power supply 8 Device

Claims

Electromechanical brake actuator (4) for an electromechanical braking system (1), wherein the brake actuator (4) comprises: - a supply terminal (4a) configured to receive electrical energy from a power supply (6); and - a control terminal (4b) configured to receive electrical control signals when the brake actuator (4) is supplied via the supply terminal (4a) in order to actuate a brake; wherein the brake actuator (4) is configured to be operated by energy supplied to the control terminal (4b) when no or insufficient energy is supplied to the supply terminal (4a) and / or when a corresponding control signal is supplied to the brake actuator (4) enabling operation by energy supplied to the control terminal (4b). Electromechanical braking system (1) for a vehicle having at least two axles (2, 3) having wheels, wherein the braking system (1) comprises: - a first electromechanical brake actuator (4); - a first power supply (6) configured to provide electrical energy to the first brake actuator (4);and a second power supply (7), wherein the braking system (1) is configured to supply the first brake actuator (4) with electrical energy from the second power supply (7) when the first power supply (6) has failed and / or when a corresponding control signal triggers a switch from the first power supply (6) to the second power supply (7), and the braking system (1) comprises a second electromechanical brake actuator (5), wherein the second power supply (7) is configured to provide energy to the second brake actuator (5) only when energy is provided to the first brake actuator (4) by the first power supply (6). Braking system (1) according to claim 2, wherein the first brake actuator (4) and the second brake actuator (5) are assigned to different wheels and / or different axles (2, 3). Braking system (1) according to one of claims 2 or 3, wherein the first brake actuator (4) is assigned to a front axle or a wheel on the front axle of the vehicle. Braking system (1) according to one of claims 2 to 4, wherein a separate connection is provided which is configured to supply the first brake actuator (4) directly with the energy from the second energy supply (7). Braking system (1) according to one of claims 2 to 5, wherein the braking system (1) is configured to supply the first brake actuator (4) with energy from the second energy supply (7) via another device (8) of the vehicle. Braking system (1) according to claim 6, wherein the braking system (1) is configured to supply the first brake actuator (4) with energy from the second energy supply (7) via a device of the braking system (1), such as a control unit. Braking system (1) according to one of claims 2 to 7, wherein the braking system (1) is configured to supply the first brake actuator (4) with energy from the second energy supply (7) at a lower power than when supplied with energy from the first energy supply (6). Braking system (1) according to one of claims 2 to 8, wherein the first brake actuator (4) comprises a brake actuator according to claim 1, wherein the supply connection (4a) is connected to the first power supply (6), and the control connection (4b) is connected to a control unit of the braking system (1), wherein the braking system (1) is configured to supply electrical energy for operating the first brake actuator (4) from the control unit to the control connection (4b) when the first power supply (6) has failed and / or when a corresponding control signal has been supplied to the first brake actuator (4) which enables operation by means of energy supplied to the control connection (4b). Vehicle with an electromechanical braking system (1) according to one of claims 2 to 9, and / or a brake actuator (4) according to claim 1, wherein the vehicle is preferably designed as a passenger car, truck, commercial vehicle, towing vehicle, semi-trailer tractor, trailer, or as a combination of towing vehicle and trailer.

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