Brake system, in particular a brake-by-wire system, comprising a master cylinder, in particular a tandem master cylinder

Abstract

A brake system comprising a master cylinder, in particular a TMC, comprising a substantially cylindrical body defining inside it an internal space with a longitudinal axis, at least one piston moving in the internal space under the thrust of an actuator, the movement of which is controlled by a brake pedal in such a way as to be controlled via a servomotor provided between the actuator and the brake pedal and electronically controlled by an electronic unit or directly by a mechanical connection with the pedal in the event of servomotor failure, or controlled via an electrical connection of the so-called cable connection type between the pedal and the electronic unit which controls the electric motor acting on the actuator; the internal space of the master cylinder is in fluid communication with a reservoir of brake fluid on the one hand via at least one inlet duct and on the other hand with at least one hydraulic brake circuit acting on the brakes via at least one outlet duct, characterized in that the system is provided with at least one suction valve provided in the path of the brake fluid between the reservoir and the at least one outlet duct; an electronic controller, ESP, capable of controlling the pump to generate a negative pressure to open the at least one suction valve; and at least one bypass channel in fluid communication on the one hand with the at least one inlet duct and on the other hand with the internal space or with the at least one outlet duct, the at least one suction valve being housed in the at least one bypass channel.

Description

Technical Field

[0001] The present invention relates to a braking system including a master cylinder, particularly a tandem master cylinder (TMC), and such a master cylinder or TMC. Background Technology

[0002] The present invention relates to a master cylinder, particularly a tandem master cylinder, which is especially used in the braking system of motor vehicles, wherein a valve (particularly a suction valve) is provided in a hydraulic circuit between the brake fluid reservoir and the internal space of the master cylinder toward the brake fluid outlet pipe of the brake circuit, the valve being able to be opened and closed by a pump under the control of ESP (Electronic Stability Program) to affect the pressure of the brake fluid applied to the brake caliper.

[0003] Traditionally, it is known to install a suction valve in a vertical inlet pipe located between the internal space of the brake fluid reservoir and the master cylinder.

[0004] It is desirable to provide a master cylinder that includes such a vertically oriented suction valve, which is more compact and, in particular, has a smaller overall height, while maintaining equally good or even better brake fluid flow performance from the reservoir to the brake. Summary of the Invention

[0005] Therefore, the present invention proposes a braking system comprising a master cylinder, particularly a TMC, which is formed of a main body of a generally cylindrical shape. This main body defines an internal space with a longitudinal axis within it, in which at least one piston moves under the actuation of an actuator. The movement of the actuator is controlled by the brake pedal in such a way that: either via a booster disposed between the actuator and the brake pedal and electrically controlled by an electronic unit, or, in the event of booster failure, directly controlled by a mechanical connection to the pedal, or via an electrical connection between the pedal and an electronic unit controlling a motor acting on the actuator, i.e., a so-called drive-by-wire connection; the internal space of the master cylinder... The system is characterized by having at least one suction valve disposed in the brake fluid path between the reservoir and the at least one outlet pipe; an ESP electronic controller capable of controlling the pump to generate negative pressure to open the at least one suction valve; and at least one bypass passage that is fluidly connected to the at least one inlet pipe on one side and to an internal space or the at least one outlet pipe on the other side, wherein the at least one suction valve is accommodated in the at least one bypass passage.

[0006] Preferably, the bypass channel has a vertical longitudinal axis.

[0007] Preferably, the at least one bypass channel leads into the at least one outlet pipe.

[0008] By offsetting the valve relative to the inlet pipe in this way, the space occupied by the master cylinder in the vertical direction is reduced without compromising its efficiency and functionality. In particular, this improves the compactness of the master cylinder and also helps to improve its integration into the vehicle's braking system. Furthermore, this design improves the flow of brake fluid within the master cylinder, which further enhances braking efficiency, especially by allowing brake fluid to flow directly from the reservoir to the outlet pipe. Moreover, according to the invention, the complexity of the assembly process is minimized.

[0009] According to an advantageous embodiment, the at least one valve is disposed in a bypass channel that also extends into the upper portion of the basic body, and a plug is disposed directly above the valve to close the bypass channel from the upper side.

[0010] This particularly facilitates valve maintenance. A plug sealing the bypass passage that houses the valve is mounted on the atmospheric pressure side of the master cylinder, reducing the risk of leakage.

[0011] According to another advantageous embodiment, the at least one valve is disposed in a bypass channel that also leads to the lower portion of the basic body, and a plug is disposed directly below the valve to close the bypass channel from the lower side.

[0012] In particular, by positioning the plug directly below the at least one valve, it is ensured that if the valve fails to hold, it will only drop slightly and be held in place by the plug. This design allows the braking system to detect any minute leaks, thus providing a stop warning to the driver before complete loss of braking capability. Furthermore, the valve's ability to withstand operating forces is improved by a stop located inside the main body of the master cylinder, against which the valve body rests.

[0013] According to a preferred embodiment, the stop is formed by a shoulder in the lateral wall (transverse wall) of the vertical bypass channel.

[0014] In particular, the plug can be threaded. Thus, a plug is realized that rests against the valve to hold it in place, and the pressure acting on the valve is absorbed by the threads of the plug.

[0015] By configuring the suction valve in this way, the ESP can supplement, and even replace, the piston's role in pressurizing the fluid in the most critical situations, particularly when the piston fails and the bypass passage is blocked, thereby acting on the brakes. In particular, this ensures that the system maintains optimal fluid flow and pressure even when brake fluid viscosity increases. Similarly, in the event of an electrical fault, an emergency mode can be activated, allowing for a large supply of brake fluid via both the inlet pipe and the bypass passage to ensure effective braking, especially under extreme conditions such as when increased fluid viscosity negatively impacts flow.

[0016] This improves the fluid entry capability of the braking system.

[0017] In particular, a braking system with improved braking performance and greater convenience has been obtained, and the system is also particularly suitable for so-called cable-based braking.

[0018] Therefore, according to one embodiment, the movement of the mechanical actuator is controlled by an electronic unit that receives a signal from the brake pedal via a wire, determines the braking force based on the signal, and controls the corresponding action of the actuator via a motor accordingly.

[0019] According to another embodiment, the brake pedal sends a signal to the ESP via a wire, and the ESP determines the braking force based on the signal and accordingly controls the pump's corresponding action via the motor.

[0020] The two implementation methods described above can be combined with each other or implemented independently.

[0021] The present invention also relates to a master cylinder, particularly for use as part of the braking system of the present invention, the master cylinder, particularly a TMC, comprising a generally cylindrical body defining an internal space with a longitudinal axis therein, in which at least one piston is movable, the internal space of the master cylinder being in fluid communication with a brake fluid reservoir via at least one inlet pipe and with at least one hydraulic brake circuit acting on the brake via at least one outlet pipe, characterized in that the master cylinder is provided with at least one suction valve disposed in the brake fluid path between the reservoir and the at least one outlet pipe, and at least one bypass passage in fluid communication with the at least one inlet pipe and with the internal space or the at least one outlet pipe, the at least one suction valve being housed in the at least one bypass passage.

[0022] Preferably, the at least one bypass channel has a vertical longitudinal axis. Attached Figure Description

[0023] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings, wherein:

[0024] Figure 1 It is a schematic illustration of a vehicle having a mechanical braking system including a power-assisted brake.

[0025] Figure 2 It is a schematic diagram of a vehicle that includes a so-called brake-by-wire system;

[0026] Figure 3 This is a cross-sectional view of the main cylinder at its primary inlet pipe according to an embodiment of the present invention, wherein the valve is assembled from above;

[0027] Figure 4 This is a cross-sectional view of the main cylinder at its primary inlet pipe according to an embodiment of the present invention, wherein the valve is assembled from below;

[0028] Figure 5 yes Figure 3 A 3D view of the main cylinder; and

[0029] Figure 6 yes Figure 4 A 3D view of the main cylinder. Detailed Implementation

[0030] exist Figure 1 The diagram schematically illustrates a motor vehicle in which the driver acts on pedal P (F). pedal ) to control booster B via electronic unit, which acts on (F) out = F pedal + F bosster The primary piston moves within the internal space of the TMC 1, which includes two outlet pipes (primary outlet pipe 13 and secondary outlet pipe 14) that are respectively connected to hydraulic brake circuits C1 and C2 under the control of ESP. These hydraulic brake circuits act on the brake caliper 40.

[0031] Even if the actuator and / or booster fails, the driver may still be able to push the piston directly (so-called "push-thru" or "through-push" function).

[0032] The ESP receives braking signals from the pedal via sensors and an electronic unit, and based on these signals, the ESP can control the pump to actuate the openings of two suction valves (primary suction valve 15 and secondary suction valve 16) located between the liquid reservoir 10 (container) and the two inlet pipes (primary inlet pipe 11 and secondary inlet pipe 12) in the TMC 1, thereby enabling hydraulically controlled braking or supplementing it in case of emergency or actuator failure.

[0033] Figure 2The illustration schematically depicts a motor vehicle in which the driver operates a pedal P to control a power booster via an electronic unit, which operates under the control of ESP (Electronic Stability Program). out = F BWA On the primary piston, which moves within the internal space of TMC 1, the TMC includes two outlet pipes (primary outlet pipe 13 and secondary outlet pipe 14) connected to the hydraulic braking circuit.

[0034] The actuator BWA is not mechanically connected to the pedal, and its movement is controlled by a motor controlled by an electronic unit 41 based on signals received from a sensor 42, which determines the desired braking force based on the pedal travel and the force applied by the driver.

[0035] In the event of an actuator malfunction, the driver cannot directly push the piston, and the so-called "push thru" or "through push" function is unavailable.

[0036] The ESP receives a braking signal from the pedal via sensors and an electronic unit, and based on this signal, the ESP can control the pump to actuate the openings of two suction valves (primary suction valve 15 and secondary suction valve 16) located in the TMC 1 between the liquid reservoir 10 and two inlet pipes with vertical axes (primary inlet pipe 11 and secondary inlet pipe 12, respectively), thereby hydraulically controlling the braking or replenishing it in case of an emergency or actuator failure.

[0037] exist Figure 3 In the diagram, a master cylinder TMC, shown in a cross-sectional view at its primary inlet pipe 11, defines an internal space 9 within which primary and secondary pistons 7 and 8 move. These pistons are capable of pressurizing brake fluid or liquid from a brake reservoir 10 under the action of an actuator, for example, controllable by the driver via the brake pedal. The fluid connection between the brake reservoir and the internal space 9 is achieved through vertical inlet pipes 11 and 12, respectively, for primary and secondary applications. Brake fluid from the reservoir 10, passing through the primary inlet pipe 11, enters the internal space 9 and is propelled by the pressure generated by the pistons towards the primary outlet pipe 13, which connects to a brake circuit that allows brake fluid to pressurize and resist the brake calipers.

[0038] The primary inlet pipe 11 communicates with the reservoir 10 from above. In this first embodiment, a vertically oriented longitudinal bypass channel 5 is provided, extending from the upper side of the main cylinder to the outlet pipe 13. A suction valve 15 is disposed in the bypass channel downstream of the inlet pipe 11 and upstream of the outlet pipe 13. The same description applies to the secondary inlet pipe 12, which is associated with the longitudinal channel 6, the suction valve 16, and the secondary outlet pipe 14.

[0039] In this embodiment, brake fluid flows from the reservoir through inlet pipe 11, and then, if the valve is opened by the pump controlled by the ESP according to braking demand, it flows through intermediate channel 22 and vertical channel 5 to directly reach primary outlet pipe 13. This fluid flow is a supplement (or a replacement in case of piston failure) to the fluid flow that flows directly from the reservoir through inlet pipe 11 into the internal space 9.

[0040] The vertical axis bypass channel 5 is sealed at the top by a plug 20. Channel 6 also includes a (convex) shoulder 21 against which the valve rests to hold it. Similarly, the plug 20 is held in place by a screw connection. The function of the plug is to hold the valve in place. Furthermore, the skirt 23 in the plug that rests against the valve 15 is at least partially hollowed out, for example, by slotting, perforating, or similar design, to allow fluid to pass between the valve and the intermediate channel 22.

[0041] Compared to existing technologies, the resulting master cylinder has a smaller height because there is no longer a need for a tall inlet pipe that can accommodate the suction valve. The valve is no longer located inside the inlet pipe, but in the main bypass channel of the master cylinder itself.

[0042] The resulting master cylinder is therefore more compact. Furthermore, since the sealing plug 20 is located on the atmospheric pressure side of the TMC, the risk of leakage is reduced. Additionally, the valve can be more easily serviced via external access if necessary. The plug 20 rests against the valve to hold it in place, and the pressure acting on the valve is absorbed by the threads of the plug.

[0043] exist Figure 4 Another embodiment is shown, wherein a vertical bypass passage 5' is still provided between the primary inlet pipe 11, which is connected from above to the brake fluid reservoir (not shown), and the primary outlet pipe 13, and the valve 15 is positioned in the passage 5'.

[0044] Vertical channel 5' is below and Figure 3 The valve is sealed by a plug 20 in the same manner as the implementation method. The sealed plug is also located on the atmospheric pressure side, which greatly reduces the risk of leakage. If necessary, valve repair (maintenance) can also be performed. On the other hand, the plug rests against the valve to keep it in the proper position, and the pressure acting on the valve is absorbed by the threads of the plug.

[0045] Figure 5 and Figure 6 They are shown respectively Figure 3 and Figure 4 A 3D diagram of TMC.

[0046] exist Figure 3 and Figure 5 In this implementation, the plug directly bears the pressure of the brake fluid. Figure 4 and Figure 6 In this implementation method, the plug indirectly bears the braking pressure.

Claims

1. A braking system comprising a master cylinder, particularly a TMC, the master cylinder comprising a basic cylindrical body defining an internal space having a longitudinal axis therein, wherein at least one piston moves within the internal space under the actuation of an actuator, the movement of the actuator being controlled by a brake pedal in such a way as to control via a booster disposed between the actuator and the brake pedal and electronically controlled by an electronic unit, or directly controlled via a mechanical connection to the pedal in the event of a booster failure, or controlled via an electrical connection located between the pedal and the electronic unit controlling a motor acting on the actuator, the electrical connection being referred to as a cable connection; The internal space of the master cylinder is in fluid communication with a brake fluid reservoir via at least one inlet pipe, and in fluid communication with at least one hydraulic brake circuit acting on the brake via at least one outlet pipe. Its features are, The braking system is provided with at least one suction valve, which is located in the brake fluid path between the reservoir and the at least one outlet pipe; An electronic controller ESP, which is capable of controlling the pump to generate negative pressure to open the at least one suction valve; And at least one bypass channel, which is in fluid communication with the at least one inlet pipe on one side and with the internal space or the at least one outlet pipe on the other side, wherein the at least one suction valve is accommodated in the at least one bypass channel.

2. The system according to claim 1, characterized in that, The bypass channel has a vertical longitudinal axis.

3. The system according to claim 1 or 2, characterized in that, The at least one bypass channel leads into the at least one outlet pipe.

4. The system according to any one of claims 1 to 3, characterized in that, The at least one valve is disposed in a bypass channel within the upper portion of the basic body, and a plug is disposed directly above the valve to close the bypass channel from the top.

5. The system according to any one of claims 1 to 3, characterized in that, The at least one valve is disposed in a bypass channel within a lower portion of the basic body, and a plug is disposed directly below the valve to close the bypass channel from the lower side.

6. A master cylinder, particularly for forming part of a braking system according to any one of the preceding claims, the master cylinder, especially a TMC, comprising a basic cylindrical body defining an internal space with a longitudinal axis therein, in which at least one piston is movable, the internal space of the master cylinder being in fluid communication with a brake fluid reservoir via at least one inlet pipe and in fluid communication with at least one hydraulic brake circuit acting on a brake via at least one outlet pipe, characterized in that... The master cylinder is provided with at least one suction valve, which is disposed in the brake fluid path between the reservoir and the at least one outlet pipe; and at least one bypass channel, which is in fluid communication with the at least one inlet pipe on one side and with the internal space or the at least one outlet pipe on the other side, and the at least one suction valve is accommodated in the at least one bypass channel.

7. The master cylinder according to claim 6, characterized in that, The bypass channel has a vertical longitudinal axis.

8. The master cylinder according to claim 6 or 7, characterized in that, The at least one bypass channel leads into the at least one outlet pipe.

9. The system according to any one of claims 6 to 8, characterized in that, The at least one valve is disposed in a bypass channel within the upper portion of the basic body, and a plug is disposed directly above the valve to close the bypass channel from the top.

10. The system according to any one of claims 6 to 8, characterized in that, The at least one valve is disposed in a bypass channel within a lower portion of the basic body, and a plug is disposed directly below the valve to close the bypass channel from the lower side.

Images