Brake system and method for braking a vehicle with at least two axles

Abstract

The present invention relates to a brake system for at least two-axle vehicles, comprising a first axle unit (10) that can be mounted or is mounted on a first axle of the vehicle, and a second axle unit that can be mounted or is mounted on a second axle of the vehicle and is hydraulically separated from the first axle unit (10), the first axle unit (10) comprising a first brake circuit (12a) having a first motor-driven brake pressure generating device (14a), a first wheel brake cylinder (16a) and a first discharge valve (18a), a second motor-driven brake pressure generating device (14b), a second wheel brake cylinder (16a) and a first discharge valve (18a). a second brake circuit (12b) having a second discharge valve (18b), and a third brake circuit (12c) having a second discharge valve (18b). The first brake circuit (12a) and the second brake circuit (12b) are configured to be capable of transferring brake fluid from a connected brake fluid reservoir (20) to the wheel brake cylinders (16a, 16b) by operation of the motor-type brake pressure generating devices (14a, 14b), and to discharge brake fluid from the wheel brake cylinders (16a, 16b) to the connected brake fluid reservoir (20) via the discharge valves (18a, 18b).

Description

Technical Field

[0001] It relates to a braking system for a vehicle with at least two axles. Similarly, the present invention relates to a method for braking a vehicle with at least two axles.

Background Art

[0002] From the prior art such as Patent Document 1, for example, there are exactly two braking circuits each having two wheel brake cylinders, and each of the wheel brake cylinders is hydraulically connected to the other wheel brake cylinder of the same braking circuit and is also hydraulically connected to two other wheel brake cylinders of the other braking circuit of the braking system via the master brake cylinder of each braking system. A braking system for a two-axle vehicle is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The present invention provides a braking system for a vehicle with at least two axles having the constituent elements of claim 1 and a method for braking a vehicle with at least two axles having the constituent elements of claim 9.

Advantages of the Invention

[0005] The present invention provides a brake system for at least two-axle vehicles that has a relatively compact structure and can be produced at a relatively low manufacturing cost. As will become apparent from the following description, the brake system according to the present invention eliminates the need for conventional hydraulic piping between at least two axles of the vehicle on which the brake system is implemented. This results in a relatively large reduction in design space in each vehicle. In addition, the assembly of the brake system according to the present invention into each vehicle is also simplified accordingly.

[0006] As will become clearer from the following description, the brake system according to the present invention allows for fully automatic / autonomous adjustment of the brake pressure in each wheel brake cylinder of the first axle unit, that is, without the driver providing driver braking force. This can also be called fully automatic / autonomous pressure adjustment. Furthermore, a failure of one of the two motor-driven brake pressure generating devices of the first axle unit of the brake system according to the present invention can be easily compensated for by the use of the other motor-driven brake pressure generating device (in an enhanced or alternative manner). Accordingly, the brake system according to the present invention has the advantage of being suitable for application in vehicle types for autonomous driving.

[0007] Furthermore, the dual-circuit configuration of the first axle unit improves its robustness against leaks occurring in one of its brake circuits. Even if a leak occurs in one of the two brake circuits of the first axle unit while the vehicle equipped with it is driving autonomously or automatically, the vehicle can still be brought to at least a safe stop.

[0008] The first axle unit is preferably a "front axle unit." That is, in the brake system according to the present invention, the first brake pressure in the first wheel brake cylinder used as a front axle wheel brake cylinder and the second brake pressure in the second wheel brake cylinder, also used as a front axle wheel brake cylinder, can be adjusted fully automatically / autonomously, that is, without the driver of each vehicle providing driver braking force. However, the first axle unit may selectively be a "rear axle unit" having a first wheel brake cylinder used as a rear axle wheel brake cylinder and a second wheel brake cylinder used as a rear axle wheel brake cylinder. In this case as well, the first brake pressure in the first wheel brake cylinder and the second brake pressure in the second wheel brake cylinder can be adjusted fully automatically / autonomously.

[0009] The first axle unit is preferably configured to be hydraulically isolated from the second axle unit such that the first axle unit and the second axle unit are connected to each other via at most one signal line and / or bus line. Accordingly, in the embodiment of the brake system described herein, conventional hydraulic piping between the first axle and the second axle of a vehicle equipped with the brake system described herein is unnecessary.

[0010] In a preferred embodiment of the brake system, the first brake circuit and the second brake circuit of the first axle unit are connected to each other via brake circuit connection piping in which a shut-off valve is located, the first communication point of the brake circuit connection piping to the first brake circuit being located between the first motor-driven brake pressure generator and the first wheel brake cylinder, and the second communication point of the brake circuit connection piping to the second brake circuit being located between the second motor-driven brake pressure generator and the second wheel brake cylinder. The configuration of the embodiment of the brake system having brake circuit connection piping described herein makes it possible to use the first motor-driven brake pressure generator together with the second motor-driven brake pressure generator to increase the second brake pressure generated in the second wheel brake cylinder, and also makes it possible to use the second motor-driven brake pressure generator together with the first motor-driven brake pressure generator to increase the first brake pressure in the first wheel brake cylinder.

[0011] As a preferred development, the first brake circuit may further include a first check valve positioned between a first communication point of the brake circuit connection piping and a first motor-driven brake pressure generator, the first check valve oriented such that the transfer of brake fluid from the first communication point to the first motor-driven brake pressure generator is obstructed by the first check valve. The embodiment of the brake system described herein can compensate for failure of the first motor-driven brake pressure generator by using a second motor-driven brake pressure generator, thereby enabling the first brake pressure in the first wheel brake cylinder to be generated / increased despite the failure of the first motor-driven brake pressure generator. As an alternative or supplement, the second brake circuit may also have a second check valve positioned between a second communication point in the brake circuit connection piping and a second motor-driven brake pressure generator, the second check valve oriented such that the transfer of brake fluid from the second communication point to the second motor-driven brake pressure generator is obstructed by the second check valve. In this case, even at the “non-mechanical” fallback level of the first axle unit, active pressure generation in the second wheel brake cylinder is possible, due to the second brake pressure in the second wheel brake cylinder being generated / increased by the first motor-driven brake pressure generator. It should be explicitly stated here that equipping the brake system with the first and second check valves induces a “non-mechanical” fallback level in which, despite the failure of one of the two motor-driven brake pressure generators, autonomous / automatic braking of each vehicle is still possible due to pressure generation in both wheel brake cylinders of the first axle unit.

[0012] In another preferred embodiment of the brake system, the first brake circuit has a first isolation valve positioned between a first motor-driven brake pressure generator and a first wheel brake cylinder, and / or the second brake circuit has a second isolation valve positioned between a second motor-driven brake pressure generator and a second wheel brake cylinder. This allows for individualized pressure adjustment of both wheel brake cylinders of the first axle unit. This can also be rephrased as fully automatic / autonomous individualized pressure adjustment of the wheel brake cylinders of the first axle unit of the brake system according to the present invention as described herein. However, it should be noted that the switching of the first and / or second isolation valves for fully automatic / autonomous individualized pressure adjustment of the wheel brake cylinders is usually only required for modulation, such as ESP control or ABS control. Therefore, during operation of the brake system according to the present invention as described herein, only relatively infrequent valve switching noise occurs. Therefore, the expression "good NVH characteristics (Noise, Vibration, Harshness-Characteristik)" for the brake system according to the present invention described here can also be used.

[0013] In another preferred development, the first brake circuit may have a third check valve arranged in parallel with the first separator valve, the third check valve oriented such that the transfer of brake fluid from the first wheel brake cylinder to the first motor-driven brake pressure generator is obstructed by the third check valve, and / or the second brake circuit may have a fourth check valve arranged in parallel with the second separator valve, the fourth check valve oriented such that the transfer of brake fluid from the second wheel brake cylinder to the second motor-driven brake pressure generator is obstructed by the fourth check valve. In the embodiments of the brake systems described herein, when the first / second separator valve is “stuck” in its closed position, the first / second motor-driven brake pressure generator can nevertheless transfer brake fluid to the first / second wheel brake cylinder via the third / fourth check valve. Thus, adding a third and / or fourth check valve to the brake system enhances the safety level of each brake system.

[0014] The first axle unit may optionally include a master brake cylinder to which a vehicle brake operating member can be connected or is connected, thereby allowing at least one piston of the master brake cylinder, which divides at least one chamber of the master brake cylinder, to be repositioned by operation of the brake operating member by the vehicle driver, and at least one chamber of the master brake cylinder is hydraulically connected to brake circuit connecting piping, a first brake circuit, and / or a second brake circuit via at least one valveless or valved connecting piping. In this way, the driver has the possibility of directly intervening in the brakes to the wheel brake cylinder of the first axle unit with their own driver braking force, thereby further inducing brake pressure generation in the wheel brake cylinder of the first axle unit. Accordingly, the embodiment of the brake system described herein also has a mechanical fallback level.

[0015] Preferably, the second axle unit is a two-circuit second axle unit that includes a third motor-driven brake pressure generating device, a third wheel brake cylinder attached to the first wheel of the second axle, and a third discharge valve, and a fourth motor-driven brake pressure generating device, a fourth wheel brake cylinder attached to the other wheel of the second axle, and a fourth discharge valve. The third and fourth brake circuits are configured such that, by the operation of their motor-driven brake pressure generating devices, brake fluid can be transferred from one or the other connected brake fluid reservoir to the wheel brake cylinder, and brake fluid can be discharged from the wheel brake cylinder to the connected brake fluid reservoir via the discharge valve. In this way, the advantages of the first axle unit described above can be appropriately embodied in the second axle unit as well.

[0016] The advantages described above are also guaranteed when a corresponding method for braking a vehicle with at least two axles is implemented. It should be explicitly stated that a method for braking a vehicle with at least two axles can be developed in accordance with each embodiment of the braking system described above.

[0017] Other constituent elements and advantages of the present invention will be described below with reference to the drawings. The drawings are as follows: [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic partial diagram showing an embodiment of the brake system. [Figure 2] This is a schematic partial diagram showing an embodiment of the brake system. [Figure 3] This is a schematic partial diagram showing an embodiment of the brake system. [Figure 4] This is a schematic partial diagram showing an embodiment of the brake system. [Figure 5] It is a schematic partial view showing an embodiment of a braking system. [Figure 6] It is a schematic partial view showing an embodiment of a braking system. [Figure 7] It is a schematic partial view showing an embodiment of a braking system. [Figure 8] It is a schematic partial view showing an embodiment of a braking system. [Figure 9] It is a schematic partial view showing an embodiment of a braking system. [Figure 10] It is a schematic partial view showing an embodiment of a braking system. [Figure 11] It is a flowchart for explaining one embodiment of a method for braking a vehicle with at least two axes.

Embodiments for Carrying Out the Invention

[0019] FIG. 1 shows a schematic partial view of a first embodiment of a braking system.

[0020] The braking system schematically shown in FIG. 1 can be assembled to / has been assembled to a vehicle / motor vehicle with at least two axes, but the applicability of this braking system is not limited to a specific vehicle type / motor vehicle type of a two-axis vehicle / motor vehicle.

[0021] The brake system in Figure 1 has a first axle unit 10 that is mountable to / mounted to the first axle of the vehicle. The brake system further has at least one second axle unit that is mountable to / mounted to the second axle of the vehicle and is hydraulically separated from the first axle unit 10, although this is not concretely shown in Figure 1. The second axle unit is configured such that the operation of the second axle unit makes the first wheel of the second axle and the other wheel of the second axle brakeable / brakes. If a vehicle equipped with a brake system has more than two axles, the brake system may further include at least one third axle unit configured to be hydraulically separated from the first axle unit 10 and the second axle unit, the at least one third axle unit may also be mountable to / mounted to at least one third axle of the vehicle, and the operation of the at least one third axle unit may cause the first wheel of the at least one third axle and the other wheel of the at least one third axle to be brakeable / brakened.

[0022] The configuration of the first axle unit 10, which is hydraulically separated from the second axle unit, is understood to mean that there are no hydraulic pipes extending between the first axle unit 10 and the second axle unit. Because the first axle unit 10 is hydraulically separated from the second axle unit, the brake system in Figure 1 does not require the hydraulic pipes that are conventionally necessary between each axle equipped with a wheel brake cylinder. Consequently, this brake system has a very compact structure that saves design space. In particular, the modular structure of the brake system can be realized at a relatively low manufacturing cost. Furthermore, the first axle unit 10 and the second axle unit can be assembled as two separate units into a two-axle vehicle equipped with them. This simplifies the assembly of the brake system described here. Accordingly, the configuration of at least one third axle unit hydraulically separated from the first axle unit 10 and the second axle unit is understood to be that there are no hydraulic pipes extending between the at least one third axle unit and the first axle unit 10 or the second axle unit.

[0023] The first axle unit 10 is preferably assembled to the front axle of the vehicle as a "front axle unit," while the second axle unit and optionally at least one third axle unit are assembled to the rear axle of the vehicle as a "rear axle unit" and / or to at least one axle located between the front and rear axles of the vehicle as an "intermediate axle unit." In this case, the first axle unit 10 serves to brake the front wheels of the vehicle, while the second axle unit and optionally at least one third axle unit can brake the rear wheels and / or intermediate wheels of the vehicle. However, as an alternative, the first axle unit 10 may be assembled to the rear axle of the vehicle as a "rear axle unit" or to at least one axle located between the front and rear axles of the vehicle as an "intermediate axle unit."

[0024] The first axle unit 10 is a two-circuit first axle unit including a first brake circuit 12a and a second brake circuit 12b. The first brake circuit 12a includes a first motor-driven brake pressure generating device 14a, a first wheel brake cylinder 16a, and a first discharge valve 18a. Accordingly, the second brake circuit 12b is configured to include a second motor-driven brake pressure generating device 14b, a second wheel brake cylinder 16b, and a second discharge valve 18b. The first discharge valve 18a and / or the second discharge valve 18b are preferably switching valves. Furthermore, the first discharge valve 18a and / or the second discharge valve 18b are preferably normally closed valves.

[0025] The first motor-driven brake pressure generator 14a is configured to increase the first brake pressure in the first wheel brake cylinder 16a by operation of the first motor-driven brake pressure generator 14a, thereby enabling / brakering the first wheel of the first axle attached to the first wheel brake cylinder 16a. The second motor-driven brake pressure generator 14b is also configured to increase the second brake pressure in the second wheel brake cylinder 16b, thereby enabling / brakering the other wheel of the first axle attached to the second wheel brake cylinder 16b. Accordingly, the first brake circuit 12a and the second brake circuit 12b are configured such that, by the operation of their motor-driven brake pressure generating devices 14a or 14b, brake fluid can be transferred from the connected brake fluid reservoir 20 to the wheel brake cylinder 16a or 16b, and brake fluid can be discharged from the wheel brake cylinder 16a or 16b to the connected brake fluid reservoir 20 via their discharge valves 18a or 18b.

[0026] The dual-circuit configuration of the first axle unit 10 ensures improved robustness of the first axle unit 10 against leaks occurring in either the brake circuit 12a or 12b. Even if a leak occurs in either of the two brake circuits 12a or 12b of the first axle unit 10 during autonomous / automatic driving of a vehicle equipped with it, the components of the other brake circuit 12a or 12b can still perform their function, allowing the vehicle to at least still come to a safe stop.

[0027] Therefore, in the brake system shown in Figure 1, the high redundancy of the first axle unit 10 is achieved with only minor modifications. Furthermore, many "same" parts, i.e., parts of the same type, can be used for the first axle unit 10. Consequently, the first axle unit 10 is relatively low-cost and can be manufactured using conventionally used brake system components.

[0028] The first motor-driven brake pressure generating device 14a and / or the second motor-driven brake pressure generating device 14b may each be, for example, at least one pump. Accordingly, the first axle unit 10 can be configured at a relatively low cost. However, the configurations of the motor-driven brake pressure generating devices 14a and 14b as pumps in the first axle unit 10, as concretely shown in Figure 1, should be interpreted as illustrative only.

[0029] Furthermore, each motor-driven brake pressure generator 14a or 14b of the first axle unit 10 can be used to induce fully automatic / autonomous brake pressure generation in the wheel brake cylinder 16a or 16b of the same brake circuit 12a or 12b. In this way, both the first brake pressure in the first wheel brake cylinder 16a and the second brake pressure in the second wheel brake cylinder 16b can be generated / increased fully automatically / autonomously, that is, without the driver of each vehicle providing driver braking force. Therefore, the first axle unit 10 is particularly well suited for autonomous / automatic braking of the vehicle equipped with it, especially during the fully autonomous / automatic operation of each vehicle.

[0030] As a preferred development, in the first axle unit 10 of the first brake circuit 12a and the second brake circuit 12b described herein, a shut-off valve 24 is connected to each other via brake circuit connecting piping 22 located within it. The shut-off valve 24 may selectively be a switching valve or a continuously adjustable valve suitable for differential pressure adjustment. Preferably, the shut-off valve 24 is a normally closed shut-off valve.

[0031] The configuration of the brake circuit connection piping 22 allows for the use of a second motor-driven brake pressure generator 14b together with a first motor-driven brake pressure generator 14a to increase the first brake pressure in the first wheel brake cylinder 16a, and also allows for the use of a first motor-driven brake pressure generator 14a together with a second motor-driven brake pressure generator 14b to increase the second brake pressure in the second wheel brake cylinder 16b. Nevertheless, by closing the shut-off valve 24, leakage in either of the two brake circuits 12a or 12b of the first axle unit 10 can be limited in terms of its impact. The first communication point of the brake circuit connection piping 22 to the first brake circuit 12a is preferably located between the first motor-type brake pressure generating device 14a and the first wheel brake cylinder 16a, while the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b is preferably located between the second motor-type brake pressure generating device 14b and the second wheel brake cylinder 16b.

[0032] As another preferred development, the first brake circuit 12a further includes a first separation valve 26a positioned between a first motor-driven brake pressure generator 14a, or a first communication point of the brake circuit connection piping 22 to the first brake circuit 12a, and the first wheel brake cylinder 16a. Similarly, the second brake circuit 12b may also include a second motor-driven brake pressure generator 14b, or a second communication point of the brake circuit connection piping 22 to the second brake circuit 12b, and the second wheel brake cylinder 16b. Thus, the first wheel brake cylinder 16a can be isolated from the first motor-driven brake pressure generator 14a by closing the first separation valve 26a, while brake fluid can nevertheless be transferred to the second wheel brake cylinder 16b by the first brake pressure generator 14a. Depending on the circumstances, the second wheel brake cylinder 16b can also be isolated from the second motor-driven brake pressure generator 14b through the closing of the second isolation valve 26b, while the operation of the second motor-driven brake pressure generator 14b allows brake fluid to be transferred to the first wheel brake cylinder 16a. By equipping the first axle unit 10 with the first isolation valve 26a and / or the second isolation valve 26b in this way, wheel-specific pressure adjustment can be performed in both wheel brake cylinders 14a and 14b of the first axle unit 10 of the brake system. Fully automatic / fully autonomous wheel-specific pressure adjustment in the wheel brake cylinders 14a and 14b can be, for example, ESP control or ABS control. At least one of the isolation valves 26a and 26b of the first axle unit 10 may be selectively a switching valve or a continuously adjustable valve suitable for differential pressure adjustment. Preferably, at least one of the separation valves 26a and 26b is a normally open valve.

[0033] Optionally, the first axle unit 10 may have a first control device 28, which is designed and / or programmed to control at least a first motor-driven brake pressure generator 14a, a second motor-driven brake pressure generator 14b, a first discharge valve 18a, and a second discharge valve 18b, and optionally at least one other valve 24, 26a, and 26b of the first axle unit 10 by at least one control signal 28a, taking into account at least one brake setting signal 30, so that the operation of the first motor-driven brake pressure generator 14a makes it possible to transfer brake fluid to the first wheel brake cylinder 16a and / or the second wheel brake cylinder 16b at least temporarily, and so that the operation of the second motor-driven brake pressure generator 14b makes it possible to transfer brake fluid to the first wheel brake cylinder 16a and / or the second wheel brake cylinder 16b at least temporarily. At least one brake setting signal 30 may be output to the first control unit 28 from at least one brake operating member sensor of the vehicle, the vehicle's automatic speed control system, the second control unit of the second axle unit, and / or other stabilization devices of the brake system. The at least one brake operating member sensor may be, for example, a rod stroke sensor and / or a stroke difference sensor. The automatic speed control system may be, for example, an automatic for unmanned driving of the vehicle, a cruise control system for maintaining a safe distance between vehicles, and / or an emergency braking system. Other stabilization devices of the vehicle can be understood to be, in particular, an ESP control unit and an ABS control unit. Thus, the first axle unit 10 can cooperate with a number of different electronic components for pressure regulation in the wheel brake cylinders 14a and 14b.

[0034] As a preferred development, the first control device 28 may be configured to receive and evaluate sensor signals from a feed pressure sensor (not shown) of the first axle unit 10, sensor signals from at least one wheel pressure sensor (not shown) of the first axle unit 10, and sensor signals from at least one wheel rotation speed sensor, yaw rate sensor, and / or acceleration sensor (not specifically shown) of at least one wheel of the vehicle's first axle. Similarly, the control device 28 may be designed to jointly control at least one motor of the vehicle, which is used as a generator for the vehicle's regenerative braking (not shown in Figure 1), or to notify the motor of preferred information for the vehicle's regenerative braking.

[0035] Figure 2 shows a schematic partial view of a second embodiment of the brake system.

[0036] The brake system / first axle unit 10 schematically shown in Figure 2, as an evolution of the embodiment in Figure 1, further includes a first check valve 32a positioned between the first communication point of the brake circuit connection piping 22 to the first brake circuit 12a and the first motor-driven brake pressure generating device 14a. The first check valve 32a is oriented such that the transfer of brake fluid from the first communication point of the brake circuit connection piping 22 to the first brake circuit 12a to the first motor-driven brake pressure generating device 14a is obstructed by the first check valve 32a. Equipping the first brake circuit 12a with the first check valve 32a makes it possible to generate brake pressure in the first wheel brake cylinder 16a solely by the operation of the second motor-driven brake pressure generating device 14b, especially in the event of a failure of the first motor-driven brake pressure generating device 14a. This is because the first check valve 32a obstructs the transfer of brake fluid to the connected brake fluid reservoir 20 via the first motor-driven brake pressure generating device 14a. The second brake circuit 12b also preferably has a second check valve 32b positioned between the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b and the second motor-driven brake pressure generating device 14b, and this second check valve is oriented in such a direction that the transfer of brake fluid from the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b to the second motor-driven brake pressure generating device 14b is obstructed by the second check valve 32b.

[0037] Thus, if the first axle unit 10 is equipped with both check valves 32a and 32b, a failure of either of the two motor-driven brake pressure generators 14a and 14b of the first axle unit 10 can be compensated for by the use of both motor-driven brake pressure generators 14a and 14b of the first axle unit 10. In other words, active pressure generation in the first wheel brake cylinder 16a and / or the second wheel brake cylinder 16b is possible even at the "non-mechanical" fallback level of the first axle unit 10, which is embodied by both check valves 32a and 32b. In particular, at the "non-mechanical" fallback level, autonomous braking of each vehicle is also possible by the first axle unit 10.

[0038] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 2, please refer to the embodiment in Figure 1 described above.

[0039] Figure 3 shows a schematic partial view of a third embodiment of the brake system.

[0040] As a supplement to the embodiment in Figure 1, in the first axle unit 10 of the brake system in Figure 3, the first brake circuit 12a further has a third check valve 34a arranged in parallel with the first separation valve 26a, and this third check valve is oriented in such a direction that the transfer of brake fluid from the first wheel brake cylinder 16a to the first motor-driven brake pressure generating device 14a is obstructed by the third check valve 34a. When the first separation valve 26a is closed and "stuck and unable to move", the first motor-driven brake pressure generating device 14a can transfer brake fluid to the first wheel brake cylinder 16 via the third check valve 34a. Optionally, the second brake circuit 12b may also have a fourth check valve 34b arranged in parallel with the second separator valve 26b, the fourth check valve oriented such that the transfer of brake fluid from the second wheel brake cylinder 16b to the second motor-driven brake pressure generator 14b is obstructed by the fourth check valve 34b. In this case as well, when the second separator valve 26b is closed and "stuck and unable to move", the second motor-driven brake pressure generator 14b can still transfer brake fluid to the second wheel brake cylinder 16b via the fourth check valve 34b. Thus, equipping the brake system and / or its first axle unit 10 with an additional third check valve 34a and / or fourth check valve 34b improves the safety level of each brake system.

[0041] As a preferred development, the first axle unit 10 in Figure 3 may also have a first check valve 32a and / or a second check valve 32b, as described above regarding position and orientation, thereby ensuring a “non-mechanical” fallback level. Therefore, for other constituent elements, characteristics, and advantages of the brake system in Figure 3, please refer to the embodiments in Figures 1 and 2 described above.

[0042] Figure 4 shows a schematic partial view of a fourth embodiment of the brake system.

[0043] The first axle unit 10 schematically shown in Figure 4 is distinguished from the embodiment in Figure 3 by the fact that the first communication point of the brake circuit connection piping 22 to the first brake circuit 12a is located between the first separation valve 26a and the first wheel brake cylinder 16a, while the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b is located between the second separation valve 26b and the second wheel brake cylinder 16b. Consequently, a preferred "non-mechanical" fallback level is guaranteed even though the first check valve 32a to the first brake circuit 12a and the second check valve 32b to the second brake circuit 12b are omitted. In particular, in the embodiment of Figure 4, it is preferable that the first separation valve 26a and / or the second separation valve 26b are normally open valves.

[0044] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 4, please refer to the embodiments shown in Figures 1 to 3 described above.

[0045] Figure 5 shows a schematic partial view of a fifth embodiment of the brake system.

[0046] In the brake system of Figure 5, the first axle unit 10 includes a master brake cylinder 36 to which a vehicle brake operating member 38 can be coupled / is coupled, thereby allowing at least one piston of the master brake cylinder 36, which separates at least one chamber of the master brake cylinder 36, to be repositioned / is repositioned by the operation of the brake operating member 38 by the vehicle driver. Furthermore, at least one chamber of the master brake cylinder 36 is hydraulically connected to brake circuit connection piping 22, a first brake circuit 12a and / or a second brake circuit 12b via at least one valveless or valved connection piping 40.

[0047] Thus, in the brake system of Figure 5, a mechanical fallback level is formed, in which the driver's braking force applied to the brake operating member 38 still allows the driver to generate brake pressure in the wheel brake cylinders 16a and 16b, especially if the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b fails. In this way, even if the vehicle's vehicle electrical system fails, the driver can still reliably bring the vehicle to a stop by increasing the brake pressure generated in the wheel brake cylinders 16a and 16b. The brake operating member 38 may be, for example, a brake pedal 38.

[0048] At least one master brake cylinder shut-off valve 42 may be inserted into at least one connecting pipe 40. Thus, while the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b are operating, at least one master brake cylinder shut-off valve 42 closes, shutting off the master brake cylinder 36 from the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b, so that the driver brake force applied to the brake operating member 38 does not affect the brake pressure generated in the wheel brake cylinders 16a and 16b, respectively. At least one master brake cylinder shut-off valve 42 may selectively be a switching valve or a continuously adjustable valve suitable for pressure difference adjustment. Preferably, at least one master brake cylinder shut-off valve 42 is a normally open valve. Although not shown in Figure 5, the simulator may also be connected to the master brake cylinder 36, so that when at least one master brake cylinder shut-off valve 42 is closed, the driver operating the brake operating member 38 receives a standard brake operation feel / pedal feel.

[0049] As an example, in the first axle unit 10 of Figure 5, a single connecting pipe 40 equipped with a single master brake cylinder shut-off valve 42 communicates with the area of ​​the brake circuit connecting pipe 22 between the shut-off valve 24 and the second communication point of the brake circuit connecting pipe 22 to the second brake circuit 12b. As a supplement, the first check valve 32a and the second check valve 32b may also be used in the first axle unit 10 in the positions and orientations described above, so that the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b do not impair the increase in brake pressure induced in the wheel brake cylinders 16a and 16b by the driver braking force as a "volumetric sink" during the mechanical fallback mode.

[0050] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 5, please refer to the embodiments described in Figures 1 to 4 above.

[0051] Figure 6 shows a schematic partial view of a sixth embodiment of the brake system.

[0052] In the brake system schematically shown in Figure 6, the first axle unit 10 is distinguished from the embodiment described above only by the fact that a single connecting pipe 40 is branched into two sub-pipes. As a result, the first sub-pipe of the branched connecting pipe 40 communicates with the area of ​​the brake circuit connecting pipe 22 between the shut-off valve 24 and the first communication point of the brake circuit connecting pipe 22 to the first brake circuit 12a, and the second sub-pipe of the branched connecting pipe 40 communicates with the area of ​​the brake circuit connecting pipe 22 between the shut-off valve 24 and the second communication point of the brake circuit connecting pipe 22 to the second brake circuit. Furthermore, the first master brake cylinder shut-off valve 42a is located in the first sub-pipe of the branched connecting pipe 40, while the second master brake cylinder shut-off valve 42b is located in the second sub-pipe of the branched connecting pipe 40.

[0053] As a preferred development, the first check valve 32a and the second check valve 32b may be used in the first axle unit 10 in the positions and orientations described above, so that the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b do not impair the brake pressure increase induced in the wheel brake cylinders 16a and 16b by the driver braking force, acting as a "volumetric sink" during the mechanical fallback mode.

[0054] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 6, please refer to the embodiments described in Figures 1 to 5 above.

[0055] Figure 7 shows a schematic partial view of the seventh embodiment of the brake system.

[0056] The brake system in Figure 7, schematically illustrated by the first axle unit 10, is distinguished from the embodiment in Figure 5 by the fact that the first communication point of the brake circuit connection piping 22 to the first brake circuit 12a is located between the first separation valve 26a and the first wheel brake cylinder 16a, while the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b is located between the second separation valve 26b and the second wheel brake cylinder 16b. Therefore, the closed first isolation valve 26a and / or the closed second isolation valve 26b isolate the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b from the master brake cylinder 36, thereby preventing both the first motor-driven brake pressure generator 14a and the second motor-driven brake pressure generator 14b from acting as "volumetric sinks" during the mechanical fallback mode, thereby reducing the increase in brake pressure at the wheel brake cylinders 16a and 16b caused by the driver's braking force. In particular, in the embodiment shown in Figure 7, it is preferable that the first isolation valve 26a and / or the second isolation valve 26b are normally open valves.

[0057] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 7, please refer to the embodiments shown in Figures 1 to 5 described above.

[0058] Figure 8 shows a schematic partial view of the eighth embodiment of the brake system.

[0059] Unlike the embodiment in Figure 6, in the brake system of Figure 8, the first communication point of the brake circuit connection piping 22 to the first brake circuit 12a is configured between the first isolation valve 26a and the first wheel brake cylinder 16a, and the second communication point of the brake circuit connection piping 22 to the second brake circuit 12b is configured between the second isolation valve 26b and the second wheel brake cylinder 16b. Therefore, the closed first isolation valve 26a and / or the closed second isolation valve 26b isolate the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b from the master brake cylinder 36, thereby preventing both the first motor-driven brake pressure generator 14a and the second motor-driven brake pressure generator 14b from acting as "volumetric sinks" during the mechanical fallback mode, thus preventing the increase in brake pressure at the wheel brake cylinders 16a and 16b caused by the driver's braking force. In the embodiment shown in Figure 8, it is preferable that the first separation valve 26a and / or the second separation valve 26b are normally open valves.

[0060] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 8, please refer to the embodiments described in Figures 1 to 6 above.

[0061] Figure 9 shows a schematic partial view of the ninth embodiment of the brake system.

[0062] In the brake system shown in Figure 9, the master brake cylinder 36 is a tandem-type master brake cylinder 36. The first chamber of the master brake cylinder 36 is connected to the area of ​​the first brake circuit 12a between the first motor-driven brake pressure generator 14a and the first separation valve 26a by a first connecting pipe 40a having a first master brake cylinder shut-off valve 42a, and the second chamber of the master brake cylinder 36 is connected to the area of ​​the second brake circuit 12b between the second motor-driven brake pressure generator 14b and the second separation valve 26b by a second connecting pipe 40b having a second master brake cylinder shut-off valve 42b.

[0063] In the brake system of Figure 9, the first check valve 32a and the second check valve 32b may be used in the first axle unit 10 in the positions and orientations described above, so that the first motor-driven brake pressure generator 14a and / or the second motor-driven brake pressure generator 14b do not impair the increase in brake pressure induced in the wheel brake cylinders 16a and 16b by the driver braking force, acting as a "volumetric sink" during the mechanical fallback mode.

[0064] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 9, please refer to the embodiments shown in Figures 1 to 8 described above.

[0065] Figure 10 shows a schematic partial view of a tenth embodiment of the brake system.

[0066] Unlike the embodiment in Figure 9, in the brake system of Figure 10, the first chamber of the master brake cylinder 36 is connected to the area of ​​the first brake circuit 12a between the first separator valve 26a and the first wheel brake cylinder 16a by a first connecting pipe 40a having a first master brake cylinder shut-off valve 42a, while the second chamber of the master brake cylinder 36 is connected to the area of ​​the second brake circuit 12b between the second separator valve 26b and the second wheel brake cylinder 16b by a second connecting pipe 40b having a second master brake cylinder shut-off valve 42b. Thus, the closed first separator valve 26a and / or the closed second separator valve 26b ensure that, in the brake system of Figure 10 as well, neither the first motor-driven brake pressure generator 14a nor the second motor-driven brake pressure generator 14b will impair the increase in brake pressure at the wheel brake cylinders 16a and 16b induced by the driver braking force, acting as a "volumetric sink" during the mechanical fallback mode. In particular, in the embodiment shown in Figure 10, it is preferable that the first separation valve 26a and / or the second separation valve 26b are normally open valves.

[0067] For other configuration requirements, characteristics, and advantages of the brake system shown in Figure 10, please refer to the embodiments shown in Figures 1 to 9 described above.

[0068] In any of the braking systems described above, it is preferable that the first axle unit 10 is hydraulically separated from the second axle unit, and that the first axle unit 10 and the second axle unit are connected to each other via at most one signal line and / or bus line. In this case, the connection between the first axle unit 10 and the second axle unit, embodied by at least one signal line and / or bus line, saves design space, but nevertheless allows for good cooperation between the first axle unit 10 and the second axle unit. The at least one signal line and / or bus line may be, for example, the vehicle bus of the vehicle. For example, the first control device 28 of the first axle unit 10 and the second control device of the second axle unit may be connected to each other via at least one signal line and / or bus line. However, similarly, the first axle unit 10 may be configured without its own first control unit 28, and / or the second axle unit without its own second control unit. Optionally, via at least one signal line and / or bus line, the electrically controllable components of the first axle unit 10 may be controlled by the second control unit of the second axle unit, or the electrically controllable components of the second axle unit may be controlled by the first control unit 28. Alternatively, however, the electrically controllable components of the first axle unit 10 and the electrically controllable components of the second axle unit may be controlled by an external (central) control unit.

[0069] The second axle unit of the brake system described above is preferably a two-circuit second axle unit having a third brake circuit and a fourth brake circuit. The third brake circuit may be configured to include a third motor-driven brake pressure generating device, a third wheel brake cylinder attached to the first wheel of the second axle, and a third discharge valve. Similarly, the fourth brake circuit may include a fourth motor-driven brake pressure generating device, a fourth wheel brake cylinder attached to the other wheel of the second axle, and a fourth discharge valve. In this case, the third brake circuit and the fourth brake circuit are preferably configured so that, by the operation of their motor-driven brake pressure generating devices, brake fluid can be transferred from one or the other connected brake fluid reservoir to their wheel brake cylinders, and brake fluid can be discharged from the wheel brake cylinders to the connected brake fluid reservoir via their discharge valves. In particular, any of the "axle units" shown in Figures 1 to 10 can be used as the second axle unit. Furthermore, the "axle units" shown in Figures 1 to 10 can be combined in any way. In some cases, at least one third axle unit present in the brake system may also have the constituent elements of the second axle unit described in this paragraph.

[0070] However, as an alternative, the second axle unit may have one electromechanical wheel brake for each wheel of the second axle. Thus, the second axle unit may be optionally configured as either a "hydraulic" or an "electric" axle unit. Consequently, the second axle unit can also be configured at a relatively low cost. Accordingly, at least one third axle unit, which may be present in the brake system, may also have the configuration requirements of the second axle unit described in this paragraph.

[0071] Figure 11 shows a flowchart illustrating an embodiment of a method for braking a vehicle with at least two axles.

[0072] The method described below can be implemented, for example, by the braking system described above. However, the feasibility of this method is not limited to the use of such a braking system. Nor is the feasibility of this method limited to specific vehicle / automobile models of two-axle vehicles / automobiles.

[0073] When this method is implemented, the first wheel of the first axle and the other wheel of the first axle of the vehicle are braked by the operation of at least one motor-driven brake pressure generating device of the first axle unit assembled to the first axle, which increases the first brake pressure in the first wheel brake cylinder attached to the first wheel of the first axle and the second brake pressure in the second wheel brake cylinder attached to the other wheel of the first axle. In step S1 of the method, in order to increase the first brake pressure, brake fluid is transferred from a connected brake fluid reservoir to the first wheel brake cylinder of the first brake circuit by the operation of the first motor-driven brake pressure generating device of the first brake circuit of the first axle unit, and in contrast, in order to decrease the first brake pressure, brake fluid is discharged from the first wheel brake cylinder to a connected brake fluid reservoir via the first discharge valve of the first brake circuit. Accordingly, in step S2 of the method, in order to increase the second brake pressure, brake fluid is transferred from one or the other connected brake fluid reservoir to the second wheel brake cylinder of the second brake circuit by the operation of the second motor-driven brake pressure generating device of the second brake circuit of the first axle unit, and conversely, in order to decrease the second brake pressure, brake fluid is discharged from the second wheel brake cylinder to the connected brake fluid reservoir via the second discharge valve of the second brake circuit.

[0074] Furthermore, in method step S3, the first wheel of the second axle and the other wheel of the second axle of the vehicle are braked by the operation of the second axle unit, which is assembled to the second axle and hydraulically separated from the first axle unit. Method steps S1 to S3 can be performed in any order, simultaneously, or in a time-intersecting manner.

[0075] The method described here also has the advantages already described above. To enhance or as an alternative to method step S2, the second brake pressure can be (additionally) increased by the operation of the first motor-driven brake pressure generator, which transfers brake fluid from a connected brake fluid reservoir to the second wheel brake cylinder via brake circuit connection piping having a shut-off valve located inside and controlled to open at least temporarily, a first communication point of brake circuit connection piping to the first brake circuit between the first motor-driven brake pressure generator and the first wheel brake cylinder, and a second communication point of brake circuit connection piping to the second brake circuit between the second motor-driven brake pressure generator and the second wheel brake cylinder. Accordingly, to replace or enhance method step S1, the first brake pressure can be (additionally) increased. [Explanation of Symbols]

[0076] 10. First axle unit 12a First brake circuit 12b Second brake circuit 14a, 14b Motor-driven brake pressure generating device 16a First wheel brake cylinder 16b Second wheel brake cylinder 18a First discharge valve 18b Second discharge valve 20 Connected brake fluid reservoir 22 Brake circuit connection piping 24 Shut-off valve 26a First separation valve 26b Second separation valve 32a First check valve 32b Second check valve 34a Third check valve 34b Fourth check valve 36 Master brake cylinder 38 Brake operating member 40 connecting pipes

Claims

1. A braking system for at least two-axle vehicles, The vehicle has a first axle unit (10) which is attachable to or attached to the first axle of the vehicle, and which includes a first motor-driven brake pressure generating device (14a), a second motor-driven brake pressure generating device (14b), a first wheel brake cylinder (16a), and a second wheel brake cylinder (16b), and which can increase the first brake pressure in the first wheel brake cylinder (16a) and the second brake pressure in the second wheel brake cylinder (16b) by the operation of at least one of the first motor-driven brake pressure generating device (14a) and the second motor-driven brake pressure generating device (14b), thereby enabling braking of the first wheel of the first axle attached to the first wheel brake cylinder (16a) and the other wheel of the first axle attached to the second wheel brake cylinder (16b), and A brake system comprising a second axle unit that is attachable to or attached to the second axle of the vehicle and is configured to be hydraulically separated from the first axle unit (10), thereby enabling the operation of the second axle unit to brake the first wheel of the second axle and the other wheel of the second axle, The first axle unit (10) is a two-circuit first axle unit (10) that includes a first brake circuit (12a) having a first motor-driven brake pressure generating device (14a), a first wheel brake cylinder (16a), and a first discharge valve (18a), and a second brake circuit (12b) having a second motor-driven brake pressure generating device (14b), a second wheel brake cylinder (16b), and a second discharge valve (18b), and the first brake The rake circuit (12a) and the second brake circuit (12b) are configured such that, by the operation of the motor-driven brake pressure generating device (14a, 14b), brake fluid can be transferred from the connected brake fluid reservoir (20) to the wheel brake cylinder (16a, 16b), and brake fluid can be discharged from the wheel brake cylinder (16a, 16b) to the connected brake fluid reservoir (20) via the discharge valve (18a, 18b). The first brake circuit (12a) and the second brake circuit (12b) of the first axle unit (10) are connected to each other via a brake circuit connection pipe (22) in which a shut-off valve (24) is located, the first communication portion of the brake circuit connection pipe (22) to the first brake circuit (12a) is located between the first motor-type brake pressure generating device (14a) and the first wheel brake cylinder (16a), and the second communication portion of the brake circuit connection pipe (22) to the second brake circuit (12b) is located between the second motor-type brake pressure generating device (14b) and the second wheel brake cylinder (16b). A brake system comprising: the first brake circuit (12) having a first check valve (32a) positioned between the first communication portion of the brake circuit connecting piping (22) and the first motor-driven brake pressure generating device (14a), wherein the first check valve is oriented such that the transfer of brake fluid from the first communication portion to the first motor-driven brake pressure generating device (14a) is obstructed by the first check valve (32a); and / or the second brake circuit (12b) having a second check valve (32b) positioned between the second communication portion of the brake circuit connecting piping (22) and the second motor-driven brake pressure generating device (14b), wherein the second check valve is oriented such that the transfer of brake fluid from the second communication portion to the second motor-driven brake pressure generating device (14b) is obstructed by the second check valve (32b).

2. A braking system for at least two-axle vehicles, The vehicle has a first axle unit (10) which is attachable to or attached to the first axle of the vehicle, and which includes a first motor-driven brake pressure generating device (14a), a second motor-driven brake pressure generating device (14b), a first wheel brake cylinder (16a), and a second wheel brake cylinder (16b), and which can increase the first brake pressure in the first wheel brake cylinder (16a) and the second brake pressure in the second wheel brake cylinder (16b) by the operation of at least one of the first motor-driven brake pressure generating device (14a) and the second motor-driven brake pressure generating device (14b), thereby enabling braking of the first wheel of the first axle attached to the first wheel brake cylinder (16a) and the other wheel of the first axle attached to the second wheel brake cylinder (16b), and A brake system comprising a second axle unit that is attachable to or attached to the second axle of the vehicle and is configured to be hydraulically separated from the first axle unit (10), thereby enabling the operation of the second axle unit to brake the first wheel of the second axle and the other wheel of the second axle, The first axle unit (10) is a two-circuit first axle unit (10) that includes a first brake circuit (12a) having a first motor-driven brake pressure generating device (14a), a first wheel brake cylinder (16a), and a first discharge valve (18a), and a second brake circuit (12b) having a second motor-driven brake pressure generating device (14b), a second wheel brake cylinder (16b), and a second discharge valve (18b), and the first brake The rake circuit (12a) and the second brake circuit (12b) are configured such that, by the operation of the motor-driven brake pressure generating device (14a, 14b), brake fluid can be transferred from the connected brake fluid reservoir (20) to the wheel brake cylinder (16a, 16b), and brake fluid can be discharged from the wheel brake cylinder (16a, 16b) to the connected brake fluid reservoir (20) via the discharge valve (18a, 18b). The first brake circuit (12a) has a first separation valve (26a) positioned between the first motor-driven brake pressure generating device (14a) and the first wheel brake cylinder (16a), and / or the second brake circuit (12b) has a second separation valve (26b) positioned between the second motor-driven brake pressure generating device (14b) and the second wheel brake cylinder (16b), A brake system comprising: the first brake circuit (12a) having a third check valve (34a) arranged in parallel with the first separator valve (26a), wherein the third check valve is oriented such that the transfer of brake fluid from the first wheel brake cylinder (16a) to the first motor-driven brake pressure generator (14a) is obstructed by the third check valve (34a); and / or the second brake circuit (12b) having a fourth check valve (34b) arranged in parallel with the second separator valve (26b), wherein the fourth check valve is oriented such that the transfer of brake fluid from the second wheel brake cylinder (16b) to the second motor-driven brake pressure generator (14b) is obstructed by the fourth check valve (34b).

3. The brake system according to claim 1 or 2, wherein the first axle unit (10) is configured to be hydraulically separated from the second axle unit such that the first axle unit (20) and the second axle unit are connected to each other via at least one signal line and / or bus line.

4. The brake system according to claim 1, wherein the first axle unit (10) further includes a master brake cylinder (36) to which a brake operating member (38) of the vehicle can be connected or is connected, so that at least one piston of the master brake cylinder (36), which divides at least one chamber of the master brake cylinder (36), can be positioned by operation of the brake operating member (38) by the driver of the vehicle, and at least one of the chambers of the master brake cylinder (36) is hydraulically connected to the brake circuit connecting pipe (22), the first brake circuit (12a), and / or the second brake circuit (12b) via at least one valveless or valved connecting pipe (40).

5. The brake system according to claim 1 or 2, wherein the second axle unit is a two-circuit second axle unit comprising a third motor-driven brake pressure generating device, a third wheel brake cylinder attached to the first wheel of the second axle, and a third discharge valve, and a fourth motor-driven brake pressure generating device, a fourth wheel brake cylinder attached to the other wheel of the second axle, and a fourth discharge valve, wherein the third brake circuit and the fourth brake circuit are configured to be able to transfer brake fluid from one or the other connected brake fluid reservoir to the wheel brake cylinder by the operation of the motor-driven brake pressure generating device, and to be able to discharge brake fluid from the wheel brake cylinder to the connected brake fluid reservoir via the discharge valve.

Images