Brake power assisting device, brake system and vehicle

Abstract

The invention relates to a brake booster device (1), comprising a reservoir (8) and a brake master cylinder (10), which has at least one chamber (12, 17) and at least one piston (22, 23) arranged in the chamber (12, 17), the chamber (12, 17) being connectable to a pressure regulator (14) in such a way that the piston (22, 23) can be at least partially reset by means of the pressure regulator (14), the chamber (12, 17) can be connected to the reservoir (8), and a valve (7, 9) is arranged between the chamber (12, 17) and the reservoir (8).

Description

Field of the Invention

[0001] The present invention relates to a brake assist device, a braking system, and a vehicle. Background Art

[0002] Patent document EP 2 217 478 B1 shows a braking device with a coupling that can be actuated by a brake pedal and for decoupling a drive device from a piston-cylinder unit.

[0003] Patent document DE 10 2010 003 602 A1 relates to a method for enhancing the braking force control / regulation of a braking device.

[0004] Patent document DE 10 2011 006 746 A1 shows a braking system for a vehicle.

[0005] Patent document DE 10 2015 213 710 A1 discloses an electromechanical brake force amplifier. Summary of the Invention

[0006] For a brake assist device having a reservoir and a master brake cylinder, wherein the master brake cylinder has at least one chamber and at least one piston arranged in the chamber, the core of the present invention lies in that the chamber can be connected to a pressure regulator such that the piston can be at least partially reset by means of the pressure regulator, wherein the chamber can be connected to the reservoir, and wherein a valve is arranged between the chamber and the reservoir.

[0007] The basis of the present invention is that the pressure regulator can be used to improve the resetability of the brake assist device. In particular, the pressure regulator can be temporarily activated when the reset force decreases due to an increase in the viscosity of the brake fluid at low temperatures or when the reset mechanism fails. In this case, the valve closes the inlet of the reservoir so that the pressure established by the pressure regulator remains in the chamber. Here, the valve is arranged such that when pressure is established in the chamber by the pressure regulator, it prevents the brake fluid from flowing back from the chamber to the reservoir.

[0008] Further advantageous embodiments of the present invention are the subject matter of the dependent claims.

[0009] According to an advantageous design, the valve is designed as a check valve. In this case, the check valve is arranged such that when pressure is established in the chamber by the pressure regulator, the check valve automatically closes and prevents the brake fluid from flowing back from the chamber to the reservoir.

[0010] Furthermore, it is advantageous to arrange at least one spring element in the chamber, which spring element exerts a reset force on the piston. Thus, resetting can be carried out in a compact and cost-effective manner during the normal operation of the brake assist device.

[0011] Advantageously, no additional spring element is required in the region of the mechanical mechanism of the brake booster device, in particular outside the chamber, so that the brake booster device can be designed to be compact.

[0012] It is advantageous here that the spring element is dimensioned such that the spring force of the spring element is sufficient to reset the piston from the braking position to the neutral position during normal operation of the brake booster device. Thereby, the spring force counteracting the braking force can be kept low.

[0013] Advantageously, if the spring force of the spring element is not sufficient to reset the piston to the neutral position, an additional reset force can be applied to the piston by means of a pressure regulator. Thus, the pressure regulator can be activated as needed to reset the piston to the neutral position.

[0014] Furthermore, it is advantageous that the spring element is designed as a helical spring arranged on the piston. Thereby, the brake booster device can be designed to be compact.

[0015] According to another advantageous design, the brake booster device has an electric motor and a mechanical mechanism by means of which the piston can be displaced and / or reset.

[0016] It is advantageous here that if the reset force of the electric motor is not sufficient to reset the piston from the braking position to the neutral position, an additional reset force can be applied to the piston by means of a pressure regulator. Thereby, the pressure regulator can be activated as needed to reset the piston to the neutral position

[0017] For a braking system, the core of the present invention lies in that the braking system has a brake booster device, a pressure regulator and a control device, in particular as described above or according to any one of the claims related to the brake booster device, wherein the pressure regulator can be operated by means of the control device.

[0018] The basis of the present invention is that the control device is arranged to identify an application scenario in which the reset force acting on the piston is not sufficient to reset the piston to the neutral position. In addition, the control device is arranged to activate the pressure regulator in order to provide sufficient hydraulic pressure to reset the piston.

[0019] It is advantageous here that the braking system has a vehicle stability system, wherein the vehicle stability system has the pressure regulator and / or the control device. Thus, no additional pressure source is required to reset the piston. The braking system can be designed to be compact.

[0020] For a vehicle, the core of the present invention lies in that the vehicle has a brake booster as described above or according to any one of the claims related to the brake booster device, and / or a brake system as described above or according to any one of the claims related to the brake system.

[0021] The basis of the present invention lies in improving the resetability of the brake booster device.

[0022] If meaningful, the above design solutions and improvement solutions can be arbitrarily combined with each other. Other possible design solutions, improvement solutions and embodiments of the present invention also include combinations of invention features not explicitly mentioned previously or below regarding the embodiments. In particular, those skilled in the art will also add various aspects as improvements or supplements to the corresponding basic forms of the present invention. Brief Description of the Drawings

[0023] In the following part, the present invention will be explained according to an embodiment, from which additional invention features can be derived, but the scope of the present invention is not limited to these invention features. The embodiment is shown in the drawings. For this:

[0024] Figure 1 A schematic diagram of a brake booster device 1 according to an embodiment of the present invention is shown. Detailed Description of the Invention

[0025] The brake booster device 1 has a motor 6, a mechanical mechanism with a transmission member 5, a lead screw 4 and a lead screw nut 3, as well as a brake master cylinder 10 and a reservoir 8.

[0026] In the embodiment shown in the drawings, the brake master cylinder 10 has a first chamber 17 and a second chamber 12 and is thus designed as a tandem brake master cylinder. Alternatively, the brake master cylinder 10 may also have only a single chamber, in which a single piston with a single spring element is arranged.

[0027] The brake master cylinder 10 has a first piston 22 and a second piston 23, wherein the first piston 22 is arranged in the first chamber 17 and the second piston 23 is arranged in the second chamber 12. The second piston 23 can be offset by means of the first piston 22. The first piston 22 is connected to a first spring element 16, and the second piston 23 is connected to a second spring element 11. The corresponding spring elements 11, 16 are arranged to exert a reset force on the corresponding pistons 22, 23. The spring elements 11, 16 are designed as helical springs, for example.

[0028] The first chamber 17 can be hydraulically connected to the reservoir 8 by means of a first connecting line 24. Here, a first valve 7 is arranged between the first chamber 17 and the reservoir 8.

[0029] The second chamber 12 can be hydraulically connected to the reservoir 8 via the second connecting line 25. Here, a second valve 9 is arranged between the second chamber 12 and the reservoir 8.

[0030] The first valve 7 and / or the second valve 9 are preferably designed as respective check valves.

[0031] The master brake cylinder 10 is connected to a brake circuit system (not shown in the figure) via at least one supply line 26. Preferably, each chamber 12, 17 has a respective supply line 26 connected to the corresponding brake circuit.

[0032] The brake booster 1 can be actuated by means of an actuating device 2, which can be connected, for example, to the brake pedal. Here, the actuating device 2 is arranged such that the driver braking force applied to the actuating device 2 causes the lead screw 4 to be deflected. The lead screw 4 is connected to the first piston 22 and causes it to be deflected.

[0033] The actuation can be an adjustment or movement of a mechanical mechanism, whereby the braking effect on the friction brake can be activated or eliminated. As an example, the master brake cylinder 10 of the brake booster 1 can be reset from the braking position in which the friction brake acts to the neutral position.

[0034] To increase the braking force, an electric motor 6 is provided to drive the lead screw nut 3 by means of a transmission member 5. The lead screw nut 3 is connected to the lead screw 4 and is arranged to facilitate the deflection of the lead screw 4. Here, an anti-twist plate 20 is connected to the lead screw, which prevents the lead screw 4 from rotating together with the lead screw nut 3. For this purpose, the anti-twist plate 20 is connected to the rod member 21 by means of a bushing 19. When the lead screw nut 3 rotates, the anti-twist plate 20 is guided by the rod member 21 such that the lead screw 4 is deflected and a braking pressure is built up in the master brake cylinder 10.

[0035] The lead screw 4, the lead screw nut 3, the transmission member 5 and the anti-twist plate 20 are arranged within the housing 18.

[0036] The brake booster 1 is connected to the pressure regulator 14. For this purpose, a first input line 15 is arranged between the first chamber 17 and the pressure regulator 14. A second input line 13 is arranged between the second chamber 12 and the pressure regulator 14.

[0037] The respective input lines 13, 15 extend through the cylinder housing of the master brake cylinder 10. Here, the respective input lines 13, 15 are arranged such that the volume flow from the pressure regulator 14 can flow into the respective chambers 12, 17 when the respective pistons 22, 23 are in any position.

[0038] The pressure regulator 14 can be included in the brake booster device 1, arranged outside the brake booster device and be an independent device, or the driving stability system (ESP) can assume the function of the pressure regulator 14 (if there are multiple pressure regulators, the ESP can also be referred to as an additional pressure regulator).

[0039] The pressure regulator 14 can be connected to or include a pump and a storage device for hydraulic fluid, and can cause the action of a specific liquid volume to establish or reduce a specific pressure at the brake master cylinder 10. With this liquid volume, a pressure can be generated that counteracts the movement that brings about the braking effect at the brake master cylinder 10.

[0040] The pressure regulator 14 is operated by a control device not shown in the figure. This control device can be designed as a component of the brake booster device 1 or separated from the brake booster device 1. As an example, it can be the control device of the driving stability system (ESP).

[0041] Therefore, the pistons 22, 23 in the brake master cylinder 10 can be reset by means of the hydraulic pressure established by the pressure regulator 14. Here, during the reset of the pistons 22, 23, the pressure regulator 14 supports the spring elements 11, 16. Therefore, the reset force acting on the pistons 22, 23 is the sum of the spring forces of the first spring element 16 and the second spring element 11 and the hydraulic pressure of the pressure regulator 14.

[0042] Here, the spring elements 11, 16 are dimensioned such that during the normal operation of the brake booster device 1, the spring forces of the spring elements 11, 16 are sufficient to reset the pistons 22, 23 to the neutral position after the braking process is completed, in which no braking force acts on the brake circuit system. In application scenarios where the spring forces of the spring elements 11, 16 are not sufficient to reset the pistons 22, 23, the pressure regulator 14 is additionally activated, which generates an additional pressure on the pistons 22, 23, and this additional pressure resets the pistons 22, 23. As an example, this application scenario occurs in the case of low temperatures, which cause an increase in the viscosity of the brake fluid.

[0043] Alternatively, the electric motor 6 may malfunction, which can trigger the reset of the brake booster device 1 during normal operation.

[0044] The control device is set to determine the pressure in the brake master cylinder 10 and compare it with a predetermined cylinder pressure. Here, if the pressure in the brake master cylinder 10 is greater than or equal to the predetermined cylinder pressure and there is no driver braking request, a previous braking process and the necessity for reset are recognized.

[0045] Here, relatively high internal pressures may remain in chambers 12, 17, which should advantageously be reduced by resetting. The residual pressures in chambers 12, 17 automatically push pistons 22, 23 backward until the force of the hydraulic pressure acting on pistons 22, 23 balances the frictional forces in the mechanical mechanism and the connected transmission 5. Now, in order to push the mechanical mechanism and pistons 22, 23 further toward the neutral position, the volume flow into the master brake cylinder 10 can be maintained, for example, by a pump of a pressure regulator 14 or a pressure setter. Thereby, a reset force greater than the frictional force can be achieved in pistons 22, 23.

[0046] The control device is configured to conclude whether there is a driver braking request based on information about vehicle parking and / or based on the pedal position of the accelerator pedal and / or based on the position of the brake pedal on the vehicle and / or based on determining the speed and / or speed gradient of the vehicle.

[0047] The signal by which the control device can receive to activate the reset function, in particular in order to operate the pressure regulator 14 to perform the reset, can be information about whether there is a driver braking request, the measured master brake cylinder pressure, an activated brake light switch (from which it can be concluded that there is a braking request), the accelerator pedal position (from which it can be determined whether acceleration (i.e., no braking) or braking should occur), or vehicle parking information.

Claims

1. A brake booster (1), comprising a reservoir (8) and a master brake cylinder (10), wherein the master brake cylinder comprises at least one chamber (12, 17) and at least one piston (22, 23) arranged in the chamber (12, 17), It is characterized in that The chamber (12, 17) can be connected to a pressure regulator (14) so ​​that the piston (22, 23) can be at least partially reset by means of the pressure regulator (14). wherein the chamber (12, 17) is connectable to the reservoir (8), Therein, valves (7, 9) are arranged between the chambers (12, 17) and the reservoir (8).

2. The brake booster device (1) according to claim 1, It is characterized in that The valves (7, 9) are designed as non-return valves.

3. The brake booster device (1) according to any one of the preceding claims, It is characterized in that At least one spring element (11, 16) is arranged in the chamber (12, 17), which spring element exerts a restoring force on the piston (22, 23).

4. The brake booster device (1) according to claim 3, It is characterized in that The dimensions of the spring element (11, 16) are designed so that the spring force of the spring element (11, 16) is sufficient to return the piston (22, 23) from the braking position to the neutral position during normal operation of the brake booster device (1).

5. The brake booster device (1) according to claim 4, It is characterized in that If the spring force of the spring element (11, 16) is not sufficient to return the piston (22, 23) to the neutral position, an additional return force can be applied to the piston (22, 23) by means of the pressure regulator (14).

6. The brake booster device (1) according to any one of claims 3 to 5, It is characterized in that The spring element (11, 16) is designed as a helical spring arranged on the piston (22, 23).

7. The brake booster device (1) according to any one of the preceding claims, It is characterized in that The brake booster device (1) comprises an electric motor (6) and a mechanical device, by means of which the piston (22, 23) can be deflected and / or reset.

8. The brake booster device (1) according to claim 7, It is characterized in that If the restoring force of the electric motor (6) is not sufficient to restore the piston (22, 23) from the braking position to the neutral position, an additional restoring force can be applied to the piston (22, 23) by means of the pressure regulator (14).

9. A brake system comprising a brake booster device (1), a pressure regulator (14) and a control device according to any one of the preceding claims, wherein: The pressure regulator (14) can be operated by the control device.

10. The brake system according to claim 9, It is characterized in that The brake system has a vehicle stabilization system, wherein the vehicle stabilization system has the pressure regulator (14) and / or the control device.

11. A vehicle having a brake system according to any one of claims 9 or 10.

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