Hand brake control for electro-hydraulic brake system and brake system

Abstract

The invention relates to a hand brake control for an electrohydraulic brake system, wherein the hand brake control has a hydraulic pressure providing device and a hand brake lever, wherein the pressure providing device has an electric drive, a pressure cylinder and a pressure piston which is displaceable in the pressure cylinder in an actuating direction, wherein the pressure piston is designed to subject a fluid located in the pressure cylinder to a pressure. The electric drive is designed to subject the pressure piston to a force in the actuating direction, and the hand brake lever is mounted on the hand brake control so as to be pivotable about a pivot axis. Here, a return device is arranged on the hand brake control, the hand brake lever is designed to generate an actuating force on the return device when the hand brake lever is actuated, the return device is designed to generate a return force on the hand brake lever which acts counter to the actuating force, and the hand brake lever is configured such that the hand brake lever can simultaneously generate a force on the pressure piston only when the hand brake lever generates a force on the return device.

Description

Technical Field

[0001] The present invention relates to a handbrake control for an electro-hydraulic braking system, and a corresponding electro-hydraulic braking system having such a handbrake control. Background Technology

[0002] For example, DE 10 2005 024 979 A1 describes an exemplary braking system for a two-wheeled vehicle with a handbrake control, which is within the scope of this invention. The described braking system has hydraulically actuated wheel brakes and a handbrake control having a hydraulic pressure supply device having a pressure cylinder hydraulically connected to the wheel brakes and a pressure piston displaceable within the pressure cylinder in the actuation direction. Here, the pressure piston is designed to pressurize fluid located in the pressure cylinder, and a pivotally mounted handbrake lever is arranged on the pressure supply device such that the force acting on the handbrake lever is at least partially converted into a force acting on the pressure piston in the actuation direction.

[0003] In this type of braking system, modulation of the braking pressure acting on the wheel brakes is typically achieved through an arrangement consisting of an electric pump and multiple valves. For example, in the context of an anti-lock braking system (ABS), these components are actuated in a targeted manner to prevent wheel lock-up during deceleration by corresponding adjustments to the braking pressure. This type of actuation is associated with a degree of complexity in two aspects: the control of the pump and valves, and the arrangement of these components within a shared hydraulic unit. Furthermore, independent pressure build-up (if any) within the scope of autonomous driving functions can only be achieved within a very limited range. Summary of the Invention

[0004] In this context, the present invention is based on the objective of providing a handbrake control for an electro-hydraulic braking system and an electro-hydraulic braking system of this type that allows for simpler generation and modulation of hydraulic braking pressure without causing annoyance to the vehicle driver due to abnormal feedback when actuating the handbrake control.

[0005] This objective is achieved through the handbrake control and braking system described below.

[0006] In a first aspect, the present invention relates to a handbrake control for an electro-hydraulic braking system, wherein the handbrake control has a hydraulic pressure supply device and a handbrake lever, wherein the pressure supply device has an electric actuator, a pressure cylinder, and a pressure piston displaceable within the pressure cylinder in an actuation direction. The pressure piston is designed to subject fluid located in the pressure cylinder to pressure, wherein the electric actuator is designed to subject the pressure piston to a force in the actuation direction. The handbrake lever is mounted on the handbrake control so as to be pivotable about a pivot. Furthermore, a reset device is provided on the handbrake control, wherein the handbrake lever is designed to generate an actuating force on the reset device when the handbrake lever is actuated, wherein the reset device is designed to generate a reset force on the handbrake lever acting in opposition to the actuating force, and wherein the handbrake lever is configured such that the handbrake lever can simultaneously generate a force on the pressure piston only when the handbrake lever generates a force on the reset device.

[0007] "Handbrake control" should be understood here to mean an arrangement for manual actuation, particularly in the area of ​​the vehicle's control mechanism, especially the handlebars. This type of handbrake control for controlling the corresponding braking system is known, for example, for monorail motor vehicles (especially motorcycles) or multirail riding vehicles (such as four-wheeled motorcycles).

[0008] The present invention is based on the consideration of using an electric device to provide force acting on a pressure piston, rather than generating pressure by directly transmitting the force acting on the handbrake lever to the pressure piston. Control of the electric actuator is based on control signals representing the vehicle driver's braking request or the braking demand of automated driving functions (e.g., autopilot or emergency brake assist). Therefore, the corresponding pressure supply device allows the braking pressure required to implement the corresponding braking demand to be generated directly in the connected wheel brakes. Furthermore, targeted pressure reduction can be implemented via the pressure supply device, as occurs, for example, within the scope of ABS control. Accordingly, there is no need to connect an additional valve between the pressure supply device and the connected wheel brakes.

[0009] When the handbrake lever is actuated, a reset device applies a reset force to the handbrake lever according to a defined stroke-force characteristic curve. This reset force ensures that the vehicle driver is not bothered by the movement of the electrically driven pressure piston, especially movement opposite to the actuation direction. Instead, the reset device is preferably designed so that actuating the handbrake lever, due to the reset force acting in this situation, feels like actuating a typical hydraulic brake, in which there is a direct mechanical or hydraulic connection between the handbrake lever and the wheel brakes.

[0010] The dimensions and arrangement of the handbrake lever, pressure piston, and reset device are preferably selected such that, in the event of a failure of the electric actuator, for example due to a power supply failure, force can continue to be directly transmitted to the pressure piston via the handbrake lever, allowing braking pressure to continue to be generated in backup operation mode. However, during normal operation, the vehicle driver is preferably completely disengaged from the actual movement of the pressure piston.

[0011] For the generation of control signals used to actuate pressure supply devices or electric actuators and thus to generate hydraulic pressure in connected wheel brakes, according to embodiments, a handbrake control has at least one sensor device for detecting the degree of actuation of the handbrake lever. This type of sensor device may include a single sensor or multiple sensors, each designed to detect a measurement of a physical variable that can quantify the degree of actuation of the handbrake lever.

[0012] For this purpose, the pivoting stroke of, for example, the handbrake lever or the force acting on it can be determined. An advantage of using a force sensor to determine the degree of actuation is that, depending on the design and arrangement of the force sensor, a braking request can still be detected even if the handbrake lever is no longer possible to move, for example, due to a mechanical defect. An advantage of using different types of sensors based on different physical measurement variables is that the likelihood of the determined values ​​can be checked against each other, making it possible to identify malfunctions in one of these sensors.

[0013] According to a particularly preferred embodiment, the sensor device provided herein has at least one angle sensor designed to determine the pivot angle of the handbrake lever about a pivot axis.

[0014] Accordingly, according to another embodiment, the electric actuator is provided to subject the pressure piston to a force depending on the determined degree of actuation.

[0015] To ensure that the actuating force of the handbrake lever is transmitted to the reset device on the one hand, and to ensure that the actuating force of the handbrake lever is transmitted to the pressure piston when needed on the other hand, according to another embodiment, the handbrake lever has two actuating cams that project from the handbrake lever in the actuation direction. When the handbrake lever is actuated, the first actuating cam contacts the reset device, and the second actuating cam contacts the pressure piston when the handbrake lever is actuated. This is preferably achieved by spacing these actuating cams at different distances from the pivot of the handbrake lever. This configuration of the handbrake lever provides two contact areas that, when appropriately sized, ensure, on the one hand, the desired force transmission sequence between the handbrake lever and the reset device, and on the other hand, the desired force transmission sequence between the handbrake lever and the pressure piston.

[0016] To avoid an abnormal sensation during actuation of the handbrake lever, another embodiment provides that when the handbrake lever is not actuated, the first actuation cam rests on the reset device. This avoids idle travel of the handbrake lever during actuation, thus ensuring that the actuation sensation generated by the reset device is immediately transmitted through the handbrake lever during actuation.

[0017] According to another embodiment, the unintentional influence of the braking pressure generated by the pressure piston is avoided by the actuation of the handbrake lever when the handbrake lever is not actuated, as an air gap is formed between the second actuation cam and the pressure piston. Accordingly, the handbrake lever, in the unacted state, preferably rests only on the reset device, and there is no direct mechanical contact between the handbrake lever and the pressure piston. The width of the air gap is preferably selected such that even if the reset device is initially compressed due to the actuation of the handbrake lever, no contact is generated between the handbrake lever and the pressure piston. Contact is only provided between the handbrake lever and the pressure piston after slight compression of the reset device in the following situation: due to a failure of the electric actuator of the pressure supply device, the pressure piston remains in its initial position despite the actuation of the handbrake lever.

[0018] To improve the stability of the handbrake lever, according to another embodiment, the actuation cam is integrally formed with the handbrake lever. In particular, the handbrake lever can be formed of metal, especially aluminum.

[0019] To generate a pressure sensation comparable to that of a typical hydraulic brake during actuation of the handbrake lever, according to another embodiment, the reset device has at least two elastic elements with different force-stroke characteristics. Particularly preferably, the first elastic element exhibits substantially linear behavior during compression, while the force-stroke characteristic of the second element increases exponentially. Above a first localized region of compression in the reset device, the corresponding reset force is preferably generated primarily by the first elastic element, while after a certain degree of compression, further increases in the reset force are primarily provided by the second elastic element.

[0020] Specifically, for this purpose, the reset device can have an arrangement consisting of a coil spring and an elastomeric element, wherein the coil spring, for example, at least partially surrounds the elastomeric element and protrudes beyond the elastomeric element in the opposite direction of actuation. With this configuration, during actuation of the handbrake lever, only the coil spring is compressed initially, and only after a certain actuation stroke is the elastomeric element also compressed. This mimics the behavior of a typical hydraulic brake, in which, as a result of actuation, the distance (gap) between the friction pad and the friction mating element (e.g., the brake disc) must first be overcome, corresponding to a linear force distribution curve. Only when the friction pad contacts the friction mating element does the resulting reset force increase significantly due to the elastic deformation of the friction pad. Furthermore, as the actuation force increases further, the reset force can be further increased due to the deformation of the brake caliper itself.

[0021] This behavior can be simulated fairly easily by connecting at least two elastic elements in succession. However, alternatively, additional elastic elements can be provided in the reset device, and / or the arrangement of the elastic elements relative to each other can be modified to generate the desired force-stroke characteristic curve.

[0022] In order to allow the force applied by the electric actuator to be transmitted to the pressure piston, in a preferred embodiment, at least one transmission device is provided between the electric actuator and the pressure piston, the transmission device being designed to convert the rotation of the drive shaft of the electric actuator into the translation of the pressure piston along the actuation direction.

[0023] Basically, any form of transmission suitable for converting rotary motion into translational motion can be used here. Specifically, the drive shaft of the electric actuator can be oriented relative to the pressure piston or the actuation direction of the pressure piston in any desired manner. However, if, according to another embodiment, the drive shaft of the electric actuator is arranged perpendicular to the actuation direction, the transmission can have a particularly simple design. In this case, rotary motion can be converted into translational motion with a very simple device without the need for additional transmission elements to further divert the force flow between the drive shaft and the pressure piston.

[0024] Another advantageous orientation between the drive shaft and the pressure piston is a parallel arrangement of the drive shaft relative to the actuation direction of the pressure piston. In this configuration, very few transmission elements are required to redirect the force acting on the drive shaft to the pressure piston.

[0025] In a particularly preferred embodiment, the transmission device is provided with a toothed rail arranged on the pressure piston and a gear engaged in the toothed rail, the teeth of the toothed rail extending perpendicular to the actuation direction, and the electric actuator designed to subject the gear to torque. In this simple case, the rotational movement of the drive shaft can be converted into the translational movement of the pressure piston by only two transmission elements, specifically by the driven gear and the toothed rail to which the gear engages. With this very simple configuration of the transmission device, very low frictional losses are generated when the driving torque from the electric actuator is transmitted to the pressure piston.

[0026] To ensure the maximum possible stability and durability of the components involved in force transmission, according to another embodiment, a toothed rail is integrally formed with the pressure piston. Specifically, the toothed rail can be milled into the pressure piston. Furthermore, to improve the durability of the components, the area of ​​the pressure piston where the toothed rail is formed can be hardened or coated. Therefore, wear on the teeth of the toothed rail due to frictional effects can be reduced.

[0027] According to another embodiment, the transmission device further includes a reduction gear that reduces the rotational speed of the geared component relative to the rotational speed of the drive shaft of the electric actuator. In this way, a low-power but high-speed electric motor can be used as the electric actuator. Such a motor is typically smaller than an electric motor capable of producing high torque. Therefore, with this configuration, the pressure supply device can have a compact design. In this case, the reduction gear can also particularly have a multi-stage configuration.

[0028] According to another embodiment, a particularly compact structure of the transmission can be obtained as follows: the reduction transmission has at least one planetary transmission. In particular, the transmission can also have a combination of planetary transmissions and other types of transmissions forming a multi-stage transmission mechanism.

[0029] According to a preferred embodiment, the transmission device further includes a clutch mechanism designed to controllably establish or disengage the connection between the rotation of the drive shaft of the electric actuator and the translation of the pressure piston. Here, the connection between the rotation of the drive shaft and the translation of the pressure piston is equivalent to establishing a force flow from the electric actuator to the pressure piston. Essentially, any type of device suitable for controllably establishing a dynamic connection between the electric actuator and the pressure piston can be used as the clutch mechanism. In this context, the expression "controllably" means that the clutch mechanism does not open or close arbitrarily, but rather can be opened or closed through targeted actions of the clutch mechanism. For example, this control can be performed by an electronic actuator arrangement that, upon corresponding actuation, opens or closes the clutch mechanism.

[0030] The clutch device used is preferably a current-free disconnect clutch, which disconnects the connection between the electric actuator and the pressure piston in the event of a malfunction. In this way, in the event of a malfunction during the actuation of the handbrake lever and therefore during the transmission of the force of the handbrake lever to the pressure piston, the vehicle driver does not need to overcome the inertia and inherent friction of the electric actuator after a certain degree of actuation.

[0031] To ensure a defined and reproducible initial position of the pressure piston, according to another embodiment, a spring element is arranged in the pressure cylinder, the spring element being designed to subject the pressure piston to a force in the direction of its unacted initial position. Specifically, the spring element may be a helical spring, with one side supported on the base surface of the pressure cylinder and the other side supported on the front surface of the pressure piston.

[0032] In another aspect, the present invention relates to an electro-hydraulic braking system having a handbrake control as described in one of the foregoing aspects, wherein the braking system has at least one control unit and hydraulically actuated wheel brakes, wherein the wheel brakes are hydraulically connected to a pressure supply device of the handbrake control, and wherein the control unit is configured to actuate an electric actuator of the pressure supply device to generate hydraulic pressure in the wheel brakes. Specifically, the electric actuator may be controlled based on control information determined by a sensor device of the handbrake control and indicating the degree of actuation of the handbrake lever.

[0033] Here, the control unit need not be a single, continuous device. Instead, it can consist of multiple individual components, which can be installed in different locations within the vehicle. The control unit can be, for example, the vehicle's central control unit, which controls other vehicle functions besides controlling the electric actuator of the pressure supply device. However, the control unit is preferably located in the area of ​​the handbrake controls, resulting in a compact overall configuration of the braking system. In particular, the control unit can be connected to one or more wheel rotation speed sensors of the vehicle, enabling it to perform control functions of the vehicle's braking system, especially ABS control.

[0034] According to a preferred embodiment, the electric actuator of the handbrake control also includes a motor position sensor for detecting the rotational position of the rotor of the electric actuator. The control unit is preferably designed to control the electric actuator based on the motor position determined in this way and the determined demand for generating braking pressure. For example, the generated hydraulic pressure can be determined or estimated based on the determined motor position and the known transmission behavior between the rotation of the drive shaft of the electric actuator and the corresponding translation of the pressure piston along the actuation direction. This pressure can then be synchronized with the corresponding braking demand input as the handbrake lever is pivoted, and optionally, the electric actuator can be adjusted accordingly. Furthermore, the estimated hydraulic pressure can be monitored by a pressure sensor, allowing for a plausibility check of the estimated pressure. Attached Figure Description

[0035] The preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings, in which:

[0036] Figure 1 A schematic illustration of an exemplary handbrake control is shown, and

[0037] Figures 2 to 4 It shows having Figure 1 The illustration shows schematic diagrams of different operating states of an exemplary electro-hydraulic braking system with a handbrake control. Detailed Implementation

[0038] In the following text, similar or identical features are indicated by the same reference numerals.

[0039] Figure 1 A schematic illustration of an exemplary handbrake control 100 is shown in cross-sectional view. Here, the handbrake control 100 has a handbrake lever 104, which is mounted to pivot about a pivot 102, wherein... Figure 1 The illustration shows only a portion of the handbrake lever 104. The handbrake lever 104 is preferably configured as a single part and is preferably made of metal, particularly aluminum.

[0040] Furthermore, the handbrake control 100 has a pressure supply device 106 for generating hydraulic pressure in the connected wheel brakes (not shown). For this purpose, the pressure supply device 106 has a pressure cylinder 108 and a pressure piston 112 displaceable within the pressure cylinder 108 along an actuation direction 110. The pressure piston 112 on one side of the pressure cylinder 108 and the base 124 of the pressure cylinder opposite to the pressure piston 112 define a pressure chamber 114 within the pressure cylinder 108, the volume of which decreases during the movement of the pressure piston 112 along the actuation direction 110. The brake fluid located in the pressure chamber 114 is correspondingly subjected to pressure, which also dominates in the wheel brake connected to the pressure chamber 114.

[0041] To displace the pressure piston 112 along the actuation direction 110, or to subject the pressure piston 112 to a force acting along the actuation direction 110, the pressure supply device 106 has an electric actuator 116, wherein the electric actuator 116 is designed to subject the drive shaft to torque. In the illustrated embodiment, a gear 118 is arranged on the drive shaft, engaging in a toothed rail 120, which is integrally formed with the pressure piston 112. In particular, the toothed rail 120 may be milled into the pressure piston 112, wherein the teeth of the toothed rail 120 may be coated or hardened to reduce wear. With the illustrated arrangement of the gear 118 and the toothed rail 120, rotation of the drive shaft of the electric actuator 116 about an axis oriented perpendicular to the plane of the drawing is converted into translation of the pressure piston 112 along the actuation direction 110.

[0042] A transmission mechanism can be arranged between the drive shaft of the gear 118 and the electric actuator 116. This transmission mechanism can convert the rotational speed of the drive shaft into the desired rotational behavior of the gear 118, and can also deflect the direction of rotation so that, for example, the drive shaft of the electric actuator 116 can be oriented parallel to the actuation direction 110. The specific configuration of the arrangement of the electric actuator 116 relative to other elements of the pressure supply device 106 can be adapted to the available construction space in the vehicle.

[0043] Peripheral seals 122 are arranged on the pressure piston 112 to prevent accidental leakage of liquid from the pressure chamber 114 in the direction opposite to the actuation direction. Furthermore, a spring element 126 is arranged between the pressure piston 112 or the end surface of the pressure piston 112 facing the pressure chamber 114 and the base surface 124 of the pressure cylinder 108. This spring element subjects the pressure piston 112 to a force acting in the direction opposite to the actuation direction 110, such that when the pressure supply device 106 is not actuated, the pressure piston 112 adopts / occupies a defined initial position.

[0044] Furthermore, a reset device 128 is arranged on the handbrake control 100, and the reset device 128 has an arrangement of elastic elements. Additionally, a first actuating cam 130 and a second actuating cam 132 are formed on the handbrake lever 104, each actuating cam 130 and 132 protruding from the handbrake lever 104 along the actuation direction and integrally formed with the handbrake lever 104. The first actuating cam 130 rests on the reset device 128 when the handbrake lever 104 is not actuated, while the second actuating cam 132 is arranged in the region of the pressure piston 112 when the handbrake lever 104 is not actuated, but spaced apart from the rear end surface of the pressure piston 112 by a distance d.

[0045] exist Figure 1 During operation of the braking system with handbrake control 100, as illustrated by example, the actuation of the handbrake lever 104 is not directly and mechanically transmitted to the pressure piston 112 during normal operation of the braking system. Instead, the degree of actuation of the handbrake lever 104 is detected by a sensor, and the electric actuator 116 is actuated according to the detected degree of actuation in such a way that a corresponding braking pressure is generated in the pressure chamber 114 of the pressure supply device 106. For this purpose, the handbrake control 100 has a sensor device in the form of an angle sensor 134, which is designed to detect the pivot angle of the handbrake lever 104 about the pivot 102. Based on the pivot angle detected in this way, a corresponding braking pressure can be generated by the pressure supply device 106.

[0046] The following text is about Figures 2 to 4 Describes having previous information Figure 1 The different operating states of the braking system of the described handbrake control 100 are shown. An electro-hydraulic braking system 200 is illustrated, which has a handbrake control 100 and a hydraulically actuated wheel brake 202 connected to the pressure chamber 114 of the handbrake control and is shown by way of example as a disc brake. No valve is arranged between the handbrake control 100 and the wheel brake 202; therefore, the pressure generated in the pressure chamber 114 by the pressure supply device 106 is directly transmitted to the wheel brake 202.

[0047] Furthermore, the braking system 200 has a control unit 204 designed to control the electric actuator 116 of the pressure supply device 106. For this purpose, the control unit 204 is connected to the angle sensor 134 of the handbrake control 100, allowing the control unit 204 to detect the actuation degree of the handbrake lever 104, and the control unit is used to actuate the pressure supply device 106 to generate corresponding braking pressure in the wheel brakes 202. The electric actuator 116 preferably has a motor position sensor for determining the rotational position of the rotor of the electric actuator 116, wherein the determined motor position is transmitted to the control unit 204 and used by the control unit 204 to control the rotational behavior of the electric actuator 116.

[0048] Furthermore, the control unit 204 is connected to a wheel rotation speed sensor 206, which monitors the wheel rotation speed of the vehicle's wheels, which can be subjected to braking force from the wheel brakes 202. By monitoring the wheel rotation speed, the control unit 204 can, for example, implement ABS control of the braking system 100.

[0049] Although Figures 2 to 4 Each diagram in the document shows only one wheel brake, but the descriptions can also be applied to braking systems with more than one wheel brake.

[0050] Now, Figure 2 a) This braking system 200 is shown in its unacted initial state. Here, initially no force is applied to the handbrake lever 104, so there is still a distance d between the second actuation cam 132 and the rear end surface of the pressure piston 112, while the first actuation cam rests on the reset device 128.

[0051] exist Figure 2 In step b), the driver applies force 208 to the handbrake lever, causing the handbrake lever 104 to pivot about pivot 102. The reset device 128 generates a reset force on the handbrake lever 104, providing the driver with the feel of a typical hydraulic brake. Simultaneously, the pivot angle of the handbrake lever 104 about pivot 102 is detected by angle sensor 134 and evaluated by control unit 204. Based on the determined pivot angle, control unit 204 actuates the electric actuator 116 by applying torque 210 to the gear 118, which is converted into a force 212 acting on the pressure piston 112 along the actuation direction 110 through the gear 118 engaging the toothed rail 120. Therefore, the volume of the pressure chamber 114 decreases, thus increasing the hydraulic pressure within the pressure chamber 114, and consequently increasing the hydraulic pressure in the wheel brakes 202.

[0052] Because the pressure piston 112 shifts along the actuation direction 110, the distance between the second actuation cam 132 and the rear end surface of the pressure piston 112 changes to d', resulting in no mechanical contact between the handbrake lever 104 and the pressure piston 112. Therefore, during the generation of braking pressure, the vehicle driver will not feel the behavior of the electric actuator 116 through the handbrake lever 104.

[0053] Now, Figure 3 The illustration shows the execution of ABS control via control unit 204. For this purpose, control unit 204 is designed to determine the slippage of the vehicle wheels decelerated by wheel brakes 202 using the wheel rotation speed determined by wheel rotation speed sensor 206 and a vehicle reference speed. If the wheel slippage determined in this way exceeds a threshold, the braking pressure in wheel brakes 202 is reduced until the wheel slippage is again within acceptable limits.

[0054] For this purpose, Figure 3 a) This illustrates the initial state in which the vehicle driver generates a high actuation force 208 on the handbrake lever 104, which is, for example, within the range of emergency braking. Accordingly, the reset device 128 is greatly compressed. First, the corresponding actuation of the electric actuator 116 by the control unit 204 also generates a torque 210 on the gear 118, which generates a force 212 on the pressure piston 112 in the actuation direction 110, resulting in high braking pressure in the wheel brakes 202.

[0055] If the control unit 204 determines that the wheel slippage is too large at this time, the control unit will then... Figure 3 b) The actuated electric actuator 116 shown generates a torque 214 on the gear 118, which causes the pressure piston to experience a force 216 opposite to the actuation direction 110. As a result, the pressure present in the wheel brake 202 is reduced, and therefore the slippage of the corresponding vehicle wheel is reduced.

[0056] During this process, the distance between the second actuation cam 132 and the rear end surface of the pressure piston 112 is also reduced to d''. However, the size of the actuation cam 132 is preferably selected such that even if the pressure piston 112 moves in the opposite direction of actuation due to ABS control, the pressure piston 112 will not contact the second actuation cam 132, so the vehicle driver will not feel any additional restoring force via the handbrake lever 104. Therefore, annoyance to the vehicle driver can be effectively avoided.

[0057] When performing ABS control or other controls on the braking pressure generated by the pressure supply device 106, the control unit 204 can also take into account additional sensor information transmitted to the control unit 204 by corresponding additional sensors 218. For example, in such braking pressure control, the vehicle's tilt angle (especially the tilt position angle) or the vehicle's acceleration value can be taken into account.

[0058] at last, Figure 4 The third use case of the electro-hydraulic braking system 200 is shown. Figure 4 a) The braking system 200 is shown again in the unacted initial position, where no actuating force is applied to the handbrake lever 104. Therefore, there is a distance d between the second actuation cam 132 and the rear end surface of the pressure piston 112, while the first actuation cam 130 rests on the reset device 128.

[0059] Now, Figure 4 (b) illustrates a situation where the electric actuator 116 fails to generate force on the pressure piston 112. This could be due to a technical defect in the electric pressure supply device 116 or the control unit 204, or a failure in the energy supply to the braking system 200. In this case, the pivoting of the handbrake lever 104 about the pivot 102 due to the actuation force 208 no longer actuates the electric actuator 116, and therefore no longer causes displacement of the pressure piston 112. Thus, after a certain degree of actuation of the handbrake lever 104 and corresponding compression of the reset device 128, the second actuation cam 132 strikes the pressure piston 112, causing the actuation force 208 acting on the handbrake lever 104 to be at least partially transmitted to the pressure piston 112 in the form of force 220, and generating a corresponding hydraulic pressure in the pressure chamber 114, and thus generating a corresponding hydraulic pressure in the wheel brake 202. Therefore, even in the event of an electrical fault in the braking system 200, hydraulic pressure can continue to be generated by the vehicle driver when actuating the handbrake lever 104, thus enabling the vehicle to continue to be decelerated to the desired extent by the braking system 200. Only when the handbrake lever 104 generates force on the reset device 128 can the actuating force 208 acting on the handbrake lever 104 be simultaneously and directly transmitted to the pressure piston 112.

Claims

1. A handbrake control (100) for an electro-hydraulic braking system (200). in, The handbrake control (100) has a hydraulic pressure supply device (106) and a handbrake lever (104). The hydraulic pressure supply device (106) includes an electric actuator (116), a pressure cylinder (108), and a pressure piston (112), the pressure piston being able to move within the pressure cylinder (108) along the actuation direction (110). The pressure piston (112) is designed to subject the fluid in the pressure cylinder (108) to pressure. The electric actuator (116) is designed to apply a force along the actuation direction (110) to the pressure piston (112), and the handbrake lever (104) is mounted on the handbrake control (100) so as to be able to pivot about the pivot (102). The reset device (128) is disposed on the handbrake control (100), wherein the handbrake lever (104) is designed to generate an actuating force on the reset device (128) when the handbrake lever (104) is actuated, wherein the reset device (128) is designed to generate a reset force on the handbrake lever (104) that acts opposite to the actuating force, and wherein the handbrake lever (104) is configured such that the handbrake lever (104) can simultaneously generate a force on the pressure piston (112) only when the handbrake lever (104) generates a force on the reset device (128). The handbrake lever (104) has two actuation cams (130, 132) that protrude from the handbrake lever (104) along the actuation direction (110). When the handbrake lever (104) is actuated, the first actuation cam (130) contacts the reset device (128), and the second actuation cam (132) contacts the pressure piston (112) when the handbrake lever (104) is actuated.

2. The handbrake control (100) as described in claim 1, wherein, The handbrake control (100) has at least one sensor device for detecting the actuation degree of the handbrake lever (104).

3. The handbrake control (100) as described in claim 2, wherein, The sensor device has at least one angle sensor (134) designed to determine the pivot angle of the handbrake lever (104) about the pivot (102).

4. The handbrake control (100) as described in claim 2, wherein, The electric actuator (116) is designed to subject the pressure piston (112) to a force depending on the determined degree of actuation.

5. The handbrake control (100) as described in claim 3, wherein, The electric actuator (116) is designed to subject the pressure piston (112) to a force depending on the determined degree of actuation.

6. The handbrake control (100) as described in claim 1, wherein, When the handbrake lever (104) is not actuated, the first actuation cam (130) rests on the reset device (128).

7. The handbrake control (100) as described in claim 1 or 6, wherein, When the handbrake lever (104) is not actuated, an air gap (d) is formed between the second actuation cam (132) and the pressure piston (112).

8. The handbrake control (100) as described in claim 1 or 6, wherein, These actuation cams (130, 132) are integrally formed with the handbrake lever (104).

9. The handbrake control (100) as described in any one of claims 1-6, wherein, The reset device (128) has at least two elastic elements with different force-stroke characteristics.

10. An electro-hydraulic braking system (200) having a handbrake control (100) as described in any one of claims 1-9, wherein, The electro-hydraulic braking system (200) has at least one control unit (204) and a hydraulically actuated wheel brake (202), wherein the wheel brake (202) is hydraulically connected to a hydraulic pressure supply device (106) of the handbrake control (100), and wherein the control unit (204) is designed to actuate an electric drive (116) of the hydraulic pressure supply device (106) to generate hydraulic pressure in the wheel brake (202).

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