Brake pedal arrangement for an electronically controlled braking system of a motor vehicle and motor vehicle

Abstract

Brake pedal assembly (11) for an electronically controlled braking system of a motor vehicle, wherein the brake pedal assembly (11) has a pedal bearing block (2) on which a brake pedal (1) is rotatably mounted by means of a pedal axle (4), wherein - the pedal bearing block (2) and the brake pedal (1) each have a mounting point to which one end of a damping element (3) connecting the brake pedal (1) and the pedal bearing block (2) is attached, wherein - the damping element (3) has a piston rod (12) with a damping piston (13) which is guided in a fluid space (15) formed by a damper housing (14), wherein - a spring element (16) is provided in the fluid chamber (15) which presses against the head (17) of the damping piston (13) and whose spring force acts against the pushing in of the piston rod (12) into the damper housing (14), and wherein - a resistance element (18) is arranged on the piston rod (12) in a section between the end of the piston rod (12) attached at the mounting point and the damper housing (14), which forms an elastically deformable stop when the piston rod (12) is pressed into the damper housing (14), so that when the stop is reached, in addition to the spring element (16), the elastically deformable resistance element (18) acts against the further pressing of the piston rod (12) into the damper housing (14), characterized in that - the resistance element (18) consists of an elastomer, and - that the resistance element (18) is arranged outside the fluid space (15) of the damper housing (14) such that, in a starting position of the damper element (3) and the brake pedal (1), it has a defined distance to the damper housing (14) and, when the piston rod (12) is engaged in the damper housing (14), only comes into contact with the damper housing (14) after a defined engagement travel of the piston rod (12), wherein - after reaching the stop, further engagement of the piston rod (12) into the damper housing (14) is only possible against a resistance caused by an elastic deformation of the resistance element (18).

Description

[0001] The present invention relates to a brake pedal assembly for an electronically controlled braking system of a motor vehicle, wherein the brake pedal assembly comprises a pedal bearing block on which a brake pedal is rotatably mounted by means of a pedal axle. The invention further relates to a corresponding vehicle with such a brake pedal assembly.

[0002] An electronically controlled braking system can also be called a brake-by-wire system (BBW system). The difference to a conventional braking system is that The brake pedal of the BBW system is no longer connected to a hydraulic cylinder, but the braking torque requested by the driver is detected as an electrical signal by the brake pedal assembly and transmitted to the brake actuators via a corresponding electronic control unit.

[0003] The operating behavior of a brake pedal arrangement for an electronically controlled braking system is therefore not determined by a hydraulic cylinder, so that the operating characteristics can differ considerably from those of the conventional brake pedal.

[0004] A BBW system for a vehicle is known from the prior art according to DE 10 2010 000 882 A1, which comprises a pedal unit, a brake pressure sensor connectable to the wheel brakes of the vehicle, a pressure source, means for detecting the deceleration request and a pedal travel simulator whose force-displacement characteristic is controllable.

[0005] From US 2020 / 0 001 711 A1, a pedal emulator for a motor vehicle with a stall part for mounting on a pedal is known, in which the power transmission connection between the actuating part and a base part of the emulator is formed by a parallel circuit consisting of a spring system, a damper and a hysteresis generation system.

[0006] DE 60 2004 004 471 T2 discloses an emulator mechanism in combination with a motor vehicle brake pedal in a BBW system, comprising a plastic elastomer part located in a chamber together with a piston. The plastic elastomer part is arranged such that it is compressed during a forward movement of the piston, thereby increasing the pedal force required to move the piston.

[0007] Finally, DE 10 2005 036 638 A1 describes a braking system for a motor vehicle in which at least one elastic element provides the driver with a pleasant pedal feel during BBW operation.

[0008] The purpose of this application is to specify a brake pedal arrangement for an electronically controlled braking system that emulates the operating behavior of a brake pedal arrangement with a hydraulic cylinder. Furthermore, it is the purpose of specifying a corresponding motor vehicle.

[0009] The problem is solved by the features of independent claim 1. Further preferred embodiments of the invention can be found in the dependent claims, the figures, and the accompanying description.

[0010] Accordingly, the problem is solved by a brake pedal assembly for an electronically controlled braking system of a motor vehicle, wherein the brake pedal assembly comprises a pedal bearing block on which a brake pedal is rotatably mounted by means of a pedal axle. It is proposed that the pedal bearing block and the brake pedal each have a mounting point to which one end of a damping element connecting the brake pedal and the pedal bearing block is attached. The damping element comprises a piston rod with a damping piston guided in a fluid chamber formed by a damper housing. A spring element is provided in the fluid chamber, which presses against the head of the damping piston and whose spring force acts against the piston rod being pushed into the damper housing.and wherein a resistance element is arranged on the piston rod in a section between the end of the piston rod attached at the mounting point and the damper housing, which forms an elastically deformable stop when the piston rod is pressed into the damper housing, so that when the stop is reached, in addition to the spring element, the elastically deformable resistance element acts against further pressing of the piston rod into the damper housing. The resistance element is arranged outside the fluid chamber of the damper housing and consists of an elastomer. According to the invention, this arrangement of the resistance element outside the fluid chamber is selected such that, in a starting position of the damper element and the brake pedal, it has a defined distance to the damper housing and, when the piston rod is engaged in the damper housing, only comes into contact with the damper housing after a defined engagement travel of the piston rod.where, after reaching the stop, further engagement of the piston rod in the damper housing is only possible against a resistance caused by an elastic deformation of the resistance element.

[0011] The described brake pedal arrangement mimics the force-pedal angle behavior of a conventional brake pedal with a hydraulic cylinder. The damping element opposes the actuating movement of the driver's foot when the brake pedal is pressed and returns the brake pedal to its initial position after the braking process.

[0012] The force-angle behavior when the brake pedal is actuated is initially determined by the spring element, while at the same time the damping piston is moved through the fluid space of the damper housing, whereby, in addition to the opposing spring force of the spring element, a speed-dependent damping force counteracts the actuating movement.

[0013] The resistance element is preferably fixed at a defined distance on the piston rod on the side facing away from the damper housing. This allows the travel distance to the stop of the resistance element and the associated increase in the force-displacement behavior of the damper element or in the force-angle behavior of the brake pedal to be defined.

[0014] With increased pressure on the brake pedal, the piston rod, along with the damping piston in the fluid chamber and the spring element compressed within the fluid chamber, is pushed into the damper housing to such an extent that the resistance element reaches its stop, preferably against the damper housing. This means that, in addition to the spring force of the spring element, the resistance element, with its elastic deformability, also counteracts further pressure on the brake pedal. In other words, from this defined actuation angle of the brake pedal and the corresponding position of the piston rod in the damper housing of the damper element, the spring element and the resistance element are connected in parallel. This results in a progressive characteristic curve with a sharp increase in the return force of the brake pedal from the actuation angle at which the elastically deformable resistance element abuts the piston rod.Furthermore, the resistance element itself exhibits a non-linear, progressive spring characteristic under compression. Overall, such a progressive characteristic with a non-linear progression resembles that of a brake pedal assembly with a hydraulic cylinder, but without using corresponding hydraulic components. This has the advantage that a driver already accustomed to operating a conventional braking system does not need to change their operating behavior when switching to a brake-assisted braking (BBW) system. Since a change in driving behavior could, in the worst case, lead to a driving error, both comfort and safety for such a driver are increased.

[0015] After the braking process is complete, the damper spring and any elastically deformed resistance element expand again, thereby moving the piston rod back towards the brake pedal and the brake pedal to its starting position. This movement is damped by the damping piston in the fluid chamber. Preferably, the movement is stopped upon reaching the starting position by a stop buffer, which prevents noise. An angle sensor in the brake pedal assembly, measuring the rotational position and, if applicable, the rotational movement of the pedal shaft, can generate an electrical signal that can be processed by a control unit of a brake-assisted braking (BBW) system. This allows the braking torque requested by the driver to be electronically implemented and the operating behavior of a conventional brake pedal to be emulated. The angle sensor is therefore preferably configured to transmit the measurement data to a control unit.The angle sensor is preferably non-contact.

[0016] The fluid chamber is preferably filled with oil. Furthermore, the damper housing preferably has a fixed sealing element on its inside, which ensures the guidance of the piston rod within the damper housing and seals the fluid chamber against the piston rod.

[0017] According to a preferred further development, it is proposed that the pedal axle is connected to the brake pedal in a rotationally fixed manner, and that the pedal axle is rotatably mounted in the pedal bearing block, wherein the brake pedal assembly has an angle sensor arranged on the pedal bearing block which electronically detects the rotational position of the pedal axle.

[0018] The angle sensor can, for example, be attached to the pedal bearing block by means of a mounting device. In this preferred embodiment, the pedal axle moves with the brake pedal, resulting in relative movement between the pedal axle and the pedal bearing block when the brake pedal is actuated. The proposed arrangement of the angle sensor enables reliable detection of the brake pedal's position. The angle sensor can, for example, comprise a Hall sensor and / or an induction sensor.

[0019] In a preferred embodiment, the angle sensor comprises a Hall sensor and an inductive sensor. This allows for redundant detection by two sensors, which are also based on different measuring principles, resulting in overall high reliability of the brake pedal assembly.

[0020] It is further preferably proposed that a sensor target be arranged on the pedal axle, which is detected by the angle sensor, wherein the sensor target comprises a sheet metal part and a magnet. The material of the sheet metal part is preferably an electrical conductor and / or has ferromagnetic properties. The sensor target is preferably attached to one end of the pedal axle.

[0021] The sheet metal part is preferably attached to a radial arm of the pedal axle and is equipped with an inductive sensor for detecting the angular position. The magnet is preferably arranged at one end on the pivot axis of the pedal axle.

[0022] Furthermore, it is proposed that the spring element be a coil spring. A coil spring can be easily integrated into the damper housing.

[0023] Furthermore, the spring element is preferably a compression spring. The compression spring, which is preferably a coil spring, can be mounted in a simple design at the head of the damping piston and at the bottom of the damper housing, whereby the damper housing prevents the coil spring from buckling.

[0024] In a preferred embodiment, the attachment points are ball studs and at each end of the damper element there is a ball socket for attachment to one of the ball studs.

[0025] The ball sockets engage the ball studs and connect the brake pedal and pedal bearing block to the damping element, which is compressed when the brake pedal is actuated. In this preferred embodiment, the piston rod has a ball socket at its free end for attachment to the corresponding ball stud, while the other end of the piston rod, containing the damping piston, is located in the fluid chamber of the housing. Furthermore, in this advantageous embodiment, the damper housing also has a ball socket at its free end for attachment to the corresponding ball stud. This allows for simple and cost-effective mounting of the damping element. The damping element can also be easily replaced to achieve a different force-angle or force-displacement characteristic.

[0026] According to a further development, it is proposed that the ball studs have a metal base body and are overmolded with plastic. Preferably, the part of the ball stud base body that forms the seat of the ball stud in a receptacle of the brake pedal or pedal bearing block is overmolded with plastic. The plastic overmolding ensures a firm connection between the ball studs and the brake pedal or pedal bearing block.

[0027] Preferably, the resistance element is arranged outside the damper housing on the piston rod, so that the damper housing in the area around the passage opening for the piston rod can be used as a counter bearing when the resistance element strikes the surface.

[0028] In an advantageous embodiment, a thrust washer is provided on both sides of the brake pedal, which prevents noise during operation. Preferably, the thrust washers are arranged on the hub of the brake pedal. Alternatively, they can be arranged on the pedal axle.

[0029] Furthermore, the problem is solved by a motor vehicle with a brake pedal arrangement of the type described above, in particular according to one of claims 1 to 9.

[0030] The invention is explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 an exploded view of a brake pedal assembly for an electronically controlled braking system of a motor vehicle; Fig. 2 a damping element of a brake pedal assembly; Fig. 3 a sectional view of a damping element; Fig. 4 a pedal axle; Fig. 5 the underside of a brake pedal with a ball stud; Fig. 6 a pedal bearing block with a ball stud in a rear view; and Fig. 7 a schematic representation of a motor vehicle with a brake pedal arrangement.

[0031] Fig. Figure 1 shows an exploded view of an embodiment of a brake pedal assembly 11 for an electronically controlled braking system of a motor vehicle 30. The brake pedal assembly 11 has a pedal bearing block 2, which allows the connection of the brake pedal assembly 11 to the body shell of a motor vehicle 30. A brake pedal 1 is rotatably mounted on the pedal bearing block 2 by means of a pedal axle 4, with a thrust washer 9 being mounted on the hub of the brake pedal 1 between the brake pedal 1 and the pedal bearing block 2.

[0032] In this advantageous embodiment, the brake pedal 1 is connected to the pedal axle 4 in a rotationally fixed manner, so that the brake pedal 1 and the pedal axle 4 rotate together around the main axis of the pedal axle 4 when the brake pedal 1 is actuated.

[0033] An angle sensor 6 is also arranged on the pedal bearing block 2, which electronically detects the rotational position of the brake pedal 1 relative to the pedal bearing block 2 and transmits it to a control unit, for example a BBW system of a motor vehicle 30.

[0034] The pedal axle 4, see also Fig. 4, for this purpose, has a sensor target 19 on the side facing the angle sensor 6, wherein the sensor target 19 comprises a sheet metal part extending radially from the pedal axis 4 and a magnet. The sheet metal part of the sensor target 19 can be detected by an induction sensor of the angle sensor 6 and the magnet by a Hall sensor of the angle sensor 6, so that the relative angular position of the brake pedal 1 to the pedal bearing block 2 can be redundantly detected by the angle sensor 6.

[0035] Furthermore, in this embodiment, the brake pedal assembly 11 has a stop buffer 10 that limits the initial position of the brake pedal 1 and its maximum return travel, thus preventing operating noise, e.g., when suddenly releasing the brake pedal 1. In addition, a pedal cover 7 is preferably attached to the brake pedal 1 for contact with the foot.

[0036] The position of the brake pedal 1 in the brake pedal assembly 11 can thus be electronically detected, enabling the brake pedal assembly 11 to be used as part of a brake pedal assembly system in a motor vehicle 30. A damper element 3 is provided for returning the brake pedal 1 to its initial position; this element is installed between the brake pedal 1 and the pedal bearing block 2.

[0037] The damping element 3 of the brake pedal assembly 11 is in Fig. Figure 3 shows a detailed view. The damper element 3 has a piston rod 12 which is guided in a damper housing 14. At the free end of the piston rod 12 is a ball socket 22 for attachment to a ball stud 20 of the brake pedal 1, see Figure 3. Fig. 5, arranged. Furthermore, the other end of the damper element 3 also has a ball socket 23, which is attached to a ball stud 21 of the pedal bearing block 2 in the brake pedal assembly 11, see Fig. 6. A resistance element 18 is mounted on the piston rod 12. In the initial position of the damper element 3 and the brake pedal 1, the resistance element 18 maintains a defined distance from the damper housing 14, with the resistance element 18 fixed on the side facing the ball socket 22. The other side of the resistance element 18 abuts the damper housing 14 after the piston rod 12 has reached a defined position within the damper housing 14. Further movement of the piston rod 12 after the resistance element 18 abuts the damper housing 14 is only possible with elastic deformation of the resistance element 18, resulting in a progressive force-displacement characteristic of the damper element 3 from this position of the piston rod 12 onwards.

[0038] Fig. Figure 3 shows a sectional view of the damping element 3. This view shows that the piston rod 12 has a damping piston 13 at its guided end. The damping piston 13 is guided in a fluid chamber 15 formed by the damper housing 14. The fluid chamber 15 is preferably filled with oil and sealed against the piston rod 12 by a sealing element 24. The damping piston 13 dampens the movement of the piston rod 12 in the damper housing 14. Furthermore, a spring element 16, arranged in the fluid chamber 15, rests against the head 17 of the damping piston 13 and is supported on the other side by the bottom 25 of the fluid chamber 15 at the closed end of the damper housing 14. In this advantageous embodiment, the spring element 16 is a coil spring whose spring force pushes the damping piston 13 out.

[0039] When the brake is applied by pressing the brake pedal 1, the damping element 3 between the brake pedal 1 and the pedal bearing block 2 is compressed. Initially, only the spring element 16 offers a displacement-dependent resistance corresponding to the spring characteristic of the spring element 16, thus opposing the application of the brake pedal. Simultaneously, the damping piston 13 in the fluid chamber 15 generates a damping resistance that, depending on the speed, opposes the application of the brake pedal 1 or the compression of the damping element 3. When the brake pedal 1 is released, the damping piston 13 counteracts a rapid return movement by the spring element 16, so that the movement of the piston rod 12 relative to the damper housing 14 is damped in both directions.Once the piston rod 12 has reached a defined engagement distance, the resistance element 18 comes to rest against the damper housing 14, so that further engagement of the piston rod 12 is only possible against the resistance caused by the elastic deformation of the resistance element 18. This results in a sharp increase in the force-displacement characteristic of the damper element 3, thus emulating the characteristic curve of a hydraulic cylinder in a hydraulic brake system.

[0040] Fig. Figure 5 shows a close-up view of the brake pedal 1 from below, in which the ball stud 20, to which the damper element 3 with the ball socket 22 is attached, is visible. In this advantageous embodiment, the seat of the ball stud 20 in the brake pedal 1 is overmolded with plastic.

[0041] The pedal bearing block 2 is in Fig. Figure 6 shows a close-up view from below, so that the ball stud 21, to which the damping element 3 with the ball socket 23 is attached, is visible. The seat of the ball stud 21 in the pedal bearing block 2 is also preferably overmolded with plastic.

[0042] Fig. Figure 7 shows a motor vehicle 30 with a brake pedal arrangement 11 in a schematic representation. The motor vehicle 30 has an electronically controlled braking system, wherein the braking torque requested by the driver is electronically detected by the brake pedal arrangement 11, and the driver experiences a force-displacement behavior when the brake pedal 1 is actuated, which is analogous to a conventional braking system with a directly actuated hydraulic cylinder.

Claims

[1] Brake pedal assembly (11) for an electronically controlled braking system of a motor vehicle, wherein the brake pedal assembly (11) has a pedal bearing block (2) on which a brake pedal (1) is rotatably mounted by means of a pedal axle (4), wherein - the pedal bearing block (2) and the brake pedal (1) each have a mounting point to which one end of a damping element (3) connecting the brake pedal (1) and the pedal bearing block (2) is attached, wherein - the damping element (3) has a piston rod (12) with a damping piston (13) which is guided in a fluid space (15) formed by a damper housing (14), wherein - a spring element (16) is provided in the fluid chamber (15) which presses against the head (17) of the damping piston (13) and whose spring force acts against the pushing in of the piston rod (12) into the damper housing (14), and wherein - a resistance element (18) is arranged on the piston rod (12) in a section between the end of the piston rod (12) attached at the mounting point and the damper housing (14), which forms an elastically deformable stop when the piston rod (12) is pressed into the damper housing (14), so that when the stop is reached, in addition to the spring element (16), the elastically deformable resistance element (18) acts against the further pressing of the piston rod (12) into the damper housing (14), characterized by , that - the resistance element (18) consists of an elastomer, and - that the resistance element (18) is arranged outside the fluid space (15) of the damper housing (14) such that, in a starting position of the damper element (3) and the brake pedal (1), it has a defined distance to the damper housing (14) and, when the piston rod (12) is engaged in the damper housing (14), only comes into contact with the damper housing (14) after a defined engagement travel of the piston rod (12), wherein - after reaching the stop, further engagement of the piston rod (12) into the damper housing (14) is only possible against a resistance caused by an elastic deformation of the resistance element (18). [2] Brake pedal arrangement (11) according to claim 1, characterized by, that the pedal axle (4) is connected to the brake pedal (1) in a rotationally fixed manner, and that the pedal axle (4) is rotatably mounted in the pedal bearing block (2), wherein the brake pedal assembly has an angle sensor (6) arranged on the pedal bearing block (2) which electronically detects the rotational position of the pedal axle (4). [3] Brake pedal arrangement (11) according to claim 2, characterized by , that the angle sensor (6) comprises a Hall sensor and an inductive sensor. [4] Brake pedal arrangement (11) according to claim 3, characterized by , that a sensor target (19) is arranged on the pedal axle (4) which is detected by the angle sensor (6), wherein the sensor target (19) comprises a sheet metal part and a magnet. [5] Brake pedal arrangement (11) according to one of the preceding claims, characterized by , that the spring element (16) is a coil spring. [6] Brake pedal arrangement (11) according to one of the preceding claims, characterized by, that the spring element (16) is a compression spring. [7] Brake pedal arrangement (11) according to one of the preceding claims, characterized by , that the attachment points are ball studs (20,21), and at each end of the damper element (3) there is a ball socket (22,23) for attachment to one of the ball studs (20,21). [8] Brake pedal arrangement (11) according to claim 7, characterized by , that the seat of the ball stud (20) in the brake pedal (1) and the seat of the ball stud (21) in the pedal bearing block (2) are overmolded with plastic. [9] Motor vehicle (30), characterized by , that the motor vehicle (30) has a brake pedal arrangement (11) according to one of the preceding claims.

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