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

Abstract

The present disclosure relates to a brake system, in particular a brake-by-wire system, comprising a master cylinder, in particular a tandem master cylinder. A brake system comprising a master cylinder, in particular a TMC, formed by a substantially cylindrical base body which defines an internal space inside it in which at least one piston is displaced under the thrust of an actuator. The internal space of the master cylinder is in communication, on the one hand, with a reservoir of brake fluid through at least one inlet duct and, on the other hand, with at least one hydraulic brake circuit acting on the brakes through at least one outlet duct, characterized in that the brake system is provided with at least one suction valve arranged in the fluid path between the reservoir of brake fluid and the at least one outlet duct and with an electronic control unit, ESP, capable of controlling the pump to generate a negative pressure such that the at least one suction valve is opened, and with a fastening member for fastening the at least one suction valve, the fastening member comprising an elastic C-ring.

Description

Technical Field

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

[0002] The braking system is a critical component of vehicle safety, ensuring effective deceleration and control under various driving conditions. Traditional braking systems, especially those using a master cylinder, particularly a tandem master cylinder without additional mechanisms, often face limitations in fluid delivery performance under specific operating conditions. Traditional master cylinder designs rely on piston displacement within a sealed region to displace brake fluid, which can lead to flow restriction, especially under extreme conditions. Therefore, at very low temperatures, the viscosity of the brake fluid increases, further restricting its movement within the system. This restriction results in decreased braking performance and increases the risk of brake failure.

[0003] Current braking systems primarily utilize a master cylinder and related components operating on hydraulic principles. Existing solutions are insufficient to address fluid viscosity issues at low temperatures or the need to increase fluid inflow in emergency situations. This is particularly true for brake-by-wire systems, where reliance on electrical signals to initiate braking presents specific challenges, which this invention aims to overcome.

[0004] Therefore, there is a need to improve the ability of current braking systems to operate effectively under adverse conditions, especially in the case of so-called brake-by-wire systems, where the connection between the brake pedal and the master cylinder is entirely electrical, and in the event of an electrical failure, the driver loses the ability to mechanically press the master cylinder to generate the pressure required for braking on the piston. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing a braking system comprising a master cylinder, particularly a TMC, formed of a substantially cylindrical substrate defining an internal space therein, in which at least one piston is displaced by an actuator under the actuation of an actuator whose displacement is controlled by a brake pedal, or by a booster disposed between the actuator and the brake pedal and electronically controlled by an electrical unit, or, in the event of booster failure, directly controlled by a mechanical connection with the pedal, or controlled by an electrical connection between the pedal and an electrical unit controlling an electric motor acting on the actuator, referred to as drive-by-wire. The internal space of the master cylinder is connected on one hand to a brake fluid reservoir via at least one inlet pipe and on the other hand to at least one hydraulic brake circuit acting on the brake via at least one outlet pipe. The braking system is characterized by having at least one intake valve disposed in a fluid path between the brake fluid reservoir and at least one outlet pipe, and an electronic controller ESP capable of controlling a pump to generate negative pressure, thereby opening at least one intake valve, and a fastening member comprising an elastic C-ring for securing at least one intake valve.

[0006] By configuring the intake valve in this way, the ESP can supplement (or even replace) the piston's pressurization of the fluid, especially in the most critical situations, thus acting on the brakes. In particular, this ensures that the system maintains optimal fluid flow and pressure even when the brake fluid viscosity increases. Similarly, in the event of an electrical failure, a backup mode can be activated, allowing a large supply of brake fluid to ensure effective braking. Furthermore, because the valve is reliably secured, the risk of unintended valve displacement is minimized or even eliminated, thus ensuring reliable and optimal operation of the pressurized fluid flow to the brakes, especially under extreme or emergency conditions.

[0007] The fluid entry capability of the braking system is thus improved.

[0008] In particular, a braking system with improved braking performance and greater ease of use has been obtained, and it is also particularly suitable for so-called brake-by-wire.

[0009] Therefore, according to one embodiment, the displacement of the mechanical actuator is controlled by an electrical unit that receives a signal from the brake pedal via a wire, through which the electrical unit determines the braking force and thus controls the corresponding action of the actuator via an electric motor.

[0010] According to another embodiment, the brake pedal sends a signal to the ESP via a wire, the ESP determines the braking force based on the signal, and thus controls the corresponding action of the pump via an electric motor.

[0011] The two embodiments described above can be combined or implemented separately.

[0012] Preferably, at least one intake valve is housed in a corresponding inlet pipe of the master cylinder or a bypass passage of at least one corresponding inlet pipe, and an inner annular shoulder is formed on the inner wall of the inlet pipe or bypass passage, with the inner space-facing surface of the corresponding intake valve housed in the corresponding inlet pipe or passage abutting the annular shoulder.

[0013] Preferably, an annular groove is formed on the opposite side of the inner space of the annular shoulder in the inner wall, and a C-shaped ring with a complementary shape is accommodated in the groove.

[0014] Preferably, the cross-sectional shape of the ring is substantially rectangular or square.

[0015] Preferably, the square or rectangular corner has any shape extending between two straight segments that intersect to form a corner, and the distance between the end of one segment and the virtual extension line of the other segment, measured along one segment, is preferably less than 0.15 mm but greater than 0.03 mm.

[0016] In particular, when the fillet is an arc, the radius is less than 0.15 mm and greater than 0.03 mm.

[0017] Preferably, the shape of the corner corresponds to the shape of the corner of the annular groove that receives the ring.

[0018] Preferably, an intermediate annular recess is formed in the inner wall between the annular shoulder and the annular groove recess that accommodates a C-shaped ring with a complementary shape, and the annular sealing gasket is accommodated in the intermediate annular recess.

[0019] Preferably, the annular sealing gasket is radially pressed against the bottom of the central annular groove by forcefully pressing the side of the corresponding valve fitted on the annular gasket.

[0020] Preferably, the C-shaped ring supports the face of the valve facing the opposite direction to the internal space.

[0021] Specifically, at least one valve is housed in a corresponding inlet pipe and a bypass passage is provided, which extends from the upstream portion of the inlet pipe of the corresponding valve into the internal space of the master cylinder (especially the TMC).

[0022] According to another preferred embodiment, at least one suction valve is disposed in a bypass passage extending between at least one inlet pipe and the internal space or at least one outlet pipe.

[0023] According to a preferred embodiment, at least one bypass channel is formed by a main through-hole between the outside of the substrate and at least one outlet pipe and an auxiliary through-hole extending between at least one inlet pipe and the main through-hole.

[0024] Preferably, at least one suction valve is disposed in the main through hole.

[0025] Preferably, the longitudinal axis of the main through hole is parallel to the longitudinal axis of at least one inlet pipe.

[0026] According to one embodiment, the main through-hole extends from the upper side of the main cylinder and is closed at the top by a pressure ball.

[0027] The present invention also relates to a master cylinder, particularly for constituting part of a braking system according to the invention. The master cylinder, particularly a TMC, is constructed of a substantially cylindrical base, which defines an internal space within which at least one piston can be displaced. The internal space of the master cylinder is in communication with a brake fluid reservoir via at least one inlet pipe and with at least one hydraulic braking circuit acting on the brake via at least one outlet pipe. The master cylinder is characterized in that at least one intake valve is disposed in the base, located in the fluid path between the brake fluid reservoir and at least one outlet pipe, and is provided with a fastening member for securing the at least one intake valve, the fastening member comprising a resilient C-ring. Attached Figure Description

[0028] For example, a preferred embodiment of the present invention is shown in the figure.

[0029] Figure 1 This is a schematic diagram of a vehicle including a mechanical braking system with a power-assisted brake.

[0030] Figure 2 This is a schematic diagram of a vehicle that includes a so-called brake-by-wire system;

[0031] Figure 3 This is a longitudinal sectional view of a portion of a tandem master cylinder (TMC) according to an embodiment of the present invention;

[0032] Figure 4 yes Figure 3 A magnified view of a portion;

[0033] Figure 5 yes Figure 4 A magnified view of a portion; and

[0034] Figure 6 This is a 3D view of the C-shaped ring from the previous figures. Detailed Implementation

[0035] Figure 1 This schematically illustrates a motor vehicle in which the driver applies force (F) to pedal P. pedal ), so as to control the booster B (Fout = F) acting on the main piston via the electrical unit. pedal + F boosterThe main piston is displaced within the internal space of TMC 1, which includes two outlet pipes 13 and 14 that are connected to hydraulic brake circuits C1 and C2 respectively under the control of ESP acting on brake caliper 40.

[0036] Even in the event of actuator and / or booster failure, the driver still has the possibility of directly pushing the piston (a function known as "push thru").

[0037] The ESP receives a braking signal from the pedal via sensors and an electrical unit. Based on this signal, the ESP can control the pump to start the opening of two suction valves located in the TMC 1 between the liquid reservoir 10 and the two inlet pipes (main inlet pipe 11 and secondary inlet pipe 12), namely the main suction valve 15 and the secondary suction valve 16, so as to provide hydraulically controlled braking or supplementary braking in case of emergency or actuator failure.

[0038] Figure 2 The diagram schematically illustrates a motor vehicle in which the driver operates a pedal P to control a booster via an electrical unit. This booster acts on the master piston (Fout=F). BWA The main piston is displaced within the internal space of the TMC 1, which includes two outlet pipes 13 and 14, namely the main outlet pipe and the secondary outlet pipe, respectively. The outlet pipes 13 and 14 are connected to the hydraulic braking circuit under the control of the ESP.

[0039] The BWA actuator is not mechanically connected to the pedal; its displacement is controlled by an electric motor controlled by an electrical unit 41 based on signals received from a sensor 42, which determines the required braking force based on the pedal travel and the force applied by the driver.

[0040] In the event of actuator failure, the driver cannot directly push the piston (the so-called "push-through" function is unavailable).

[0041] The ESP receives a braking signal from the pedal via sensors and an electrical unit. Based on this signal, the ESP can control the pump to start and open two suction valves, namely the main suction valve 15 and the secondary suction valve 16. These two suction valves are located in the TMC 1 between the liquid reservoir 10 and two inlet pipes with a vertical axis (the main inlet pipe 11 and the secondary inlet pipe 12), thereby enabling hydraulically controlled braking or supplementary braking in case of emergency or actuator failure.

[0042] from Figure 3 As can be seen, TMC 1 includes two pistons, a main piston 7 and a secondary piston 8, which move back and forth within the internal space 9 of the cylinder under the thrust of an actuator (not shown) to generate hydraulic pressure, which is transmitted to the corresponding braking circuit through the two outlet pipes, the main outlet pipe 13 and the secondary outlet pipe 14.

[0043] The main inlet pipe 11 and the secondary inlet pipe 12 connect the brake fluid reservoir to the internal space 9.

[0044] In addition, two bypass channels 5 and 6 are provided, serving as the main bypass channel and the secondary bypass channel respectively, connecting the upstream inlet pipe of the valve to the internal space 9. These channels also lead to the outside of the cylinder body, particularly as shown above, and are sealed by a ball forcefully inserted from above.

[0045] Both channels 5 and 6 lead to the internal space, and when both pistons are in the stationary position, brake fluid is allowed to flow from the reservoir into the internal space without being propelled by the actuator and without the need for braking. Therefore, during normal operation of the system, as the two pistons increase the pressure in the internal space under the action of the actuator, they ensure the fluid supply for the brakes.

[0046] On the other hand, each inlet pipe is equipped with suction valves 15 and 16, which allow the opening of an additional connection between the tank and the internal space when the ESP starts the pump (not visible in the figure). This connection is not obstructed by the position of the piston being pressed down, especially when the piston is unintentionally locked in the pressed position.

[0047] On the other hand, when the piston is operating normally, these valves allow the amount of brake fluid delivered into the internal space to be increased by suction. This allows for increased brake fluid flow, thereby improving braking performance, especially under extreme conditions that negatively affect flow, such as increased fluid viscosity.

[0048] The inner walls of the two inlet pipes 11 and 12 (the main inlet pipe and the secondary inlet pipe) include shoulders 17, and the faces 18 of the respective valves housed in the respective pipes facing the inner space 9 are supported against the shoulders 17.

[0049] Above the shoulder 17 (i.e., on the opposite side relative to the internal space), an annular groove 21 is formed, and a C-shaped elastic ring 22 is accommodated in the recess 21 in a complementary manner.

[0050] C-ring 22 has a square cross-section with rounded corners.

[0051] The ring facing the inner space 9 and the valve face 23 support the valve face located on the opposite side of the inner space 9.

[0052] The valve thus remains in a stable position, which allows for high reliability of flow controlled by the ESP.

[0053] Between the shoulder 17 and the annular recess 21, an intermediate annular groove 24 is formed, in which an annular sealing gasket 19 is accommodated.

[0054] The corresponding valve's annular side 20 laterally supports and abuts against the annular washer to fully compress the annular washer and achieve a seal. This seal prevents brake fluid from flowing across the annular washer from the bottom to the top of the figure (see figure). Figure 4 (The arrow in the image).

[0055] To achieve this seal, the valve is adapted to be pressed against the seal, and then the seal is deformed by lateral pushing, so that its cross-section becomes an ellipse as shown in the figure.

[0056] Specifically, the TMC body can be made of metallic materials, especially aluminum. The valve can be made of steel.

Claims

1. A braking system comprising a master cylinder, particularly a TMC, formed of a substantially cylindrical substrate defining an internal space therein, wherein at least one piston is displaced within the internal space by an actuator, the displacement of which is controlled by a brake pedal or by a booster, the booster being disposed between the actuator and the brake pedal and electronically controlled by an electrical unit, or, in the event of booster failure, directly via a mechanical connection to the pedal, or via an electrical connection between the pedal and an electrical unit controlling an electric motor acting on the actuator, referred to as drive-by-wire, wherein the internal space of the master cylinder is connected, on one hand, to a brake fluid reservoir via at least one inlet pipe and on the other hand, to at least one hydraulic brake circuit acting on the brake via at least one outlet pipe, characterized in that... The braking system is provided with at least one intake valve disposed in the liquid path between the brake fluid reservoir and the at least one outlet pipe, and the braking system is provided with an electronic controller ESP that controls the pump to generate negative pressure to open the at least one intake valve, and is provided with a fastening member for securing the at least one intake valve, the fastening member including a resilient C-ring.

2. The system according to claim 1, characterized in that, The displacement of the mechanical actuator is controlled by an electrical unit that receives a signal from the brake pedal via a wire. The electrical unit determines the braking force based on the signal and thus controls the corresponding action of the actuator via an electric motor.

3. The system according to claim 1 or 2, characterized in that, The brake pedal sends a signal to the ESP via a wire. The ESP uses the signal to determine the braking force and thus controls the corresponding action of the pump via an electric motor.

4. The system according to any one of claims 1 to 3, characterized in that, The at least one intake valve is housed in the corresponding inlet pipe of the master cylinder or the bypass passage of the corresponding at least one inlet pipe, and an internal annular shoulder is formed in the inner wall of the inlet pipe or the bypass passage, with the face of the corresponding intake valve housed in the corresponding inlet pipe or passage facing the internal space abutting the annular shoulder.

5. The system according to claim 4, characterized in that, In the inner wall, on the opposite side of the internal space of the annular shoulder, an annular groove is formed, and a C-shaped ring with a complementary shape is accommodated in the groove.

6. The system according to claim 5, characterized in that, The ring has a generally rectangular or square cross-sectional shape.

7. The system according to claim 6, characterized in that, The corner of the square or rectangle has any shape extending between two straight segments that intersect to form the corresponding corner, and the distance between the end of one segment and the virtual extension line of the other segment, as measured along one segment, is preferably less than 0.15 mm but greater than 0.03 mm.

8. The system according to claim 6 or 7, characterized in that, The shape of the corner corresponds to the shape of the corner of the annular groove that accommodates the ring.

9. The system according to any one of claims 4 to 8, characterized in that, An intermediate annular recess is formed in the inner wall between the annular shoulder and the annular groove recess that accommodates a C-shaped ring with a complementary shape, and an annular sealing gasket is accommodated in the intermediate annular recess.

10. The system according to claim 9, characterized in that, The annular sealing gasket is radially pressed against the bottom of the intermediate annular groove by forcefully pressing the side of the corresponding valve fitted on the annular gasket.

11. The system according to any one of claims 1 to 10, characterized in that, The C-shaped ring supports the valve's surface, which faces in the opposite direction to the internal space.

12. A master cylinder, particularly for constituting part of a braking system according to any one of claims 1 to 11, said master cylinder, in particular a TMC, is constructed of a substantially cylindrical body defining an internal space within which at least one piston can be displaced, said internal space of said master cylinder being in communication on one hand with a brake fluid reservoir via at least one inlet pipe and on the other hand with at least one hydraulic braking circuit acting on said brake via at least one outlet pipe, characterized in that, At least one intake valve is disposed in the base, in the liquid path between the brake fluid reservoir and the at least one outlet pipe, and is provided with a fastening member for securing the at least one intake valve, the fastening member comprising a resilient C-ring.

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