Method for actuating a mechanism in a brake booster unit of a braking system and braking system

Abstract

The invention relates to a method for actuating a mechanism in a brake booster unit (10), comprising the steps of: determining (S1) whether a driver's braking intention has ended or whether there is no driver braking intention by means of a control unit (SE) of a vehicle system (ESP); identifying (S2) an operational disruption of the brake booster unit (10) using the control unit (SE); identifying (S3) an operational disruption of a pressure controller using the control unit (SE), which is connected to the brake booster unit (10) and designed to generate a braking pressure and / or a restoring pressure at a main brake cylinder unit (HZE) of the brake booster unit (10); generating (S4) a predetermined minimum pressure in the main brake cylinder unit (HZE) using the vehicle system (ESP) and thereby restoring the mechanism and, using same, restoring a main brake cylinder into a neutral position.

Description

[0001] Description

[0002] title

[0003] Method for actuating a mechanism in a

[0004] Brake booster device of a braking system and braking system

[0005] The present invention relates to a method for actuating a mechanism in a brake booster device of a brake system and to a brake system.

[0006] State of the art

[0007] When using a brake booster system, a return spring can return the position of the master cylinder to a neutral position after the braking process, thus reducing the brake pressure. The return spring can be placed on the housing of the master cylinder and limit the movement of the master cylinder in the direction of the buildup of brake pressure. In other words, a brake cylinder piston can usually only move in the direction of the master cylinder until the return spring is compressed.

[0008] Typically, a single return spring can be used to ensure the gear resetting in the brake booster for mechanical backup. This backup can be used in the event of a motor failure, such as a power failure to the motor. A braking position of the master brake cylinder can be released by the return spring taking over the return movement of the master brake cylinder and the gear unit, which would normally be moved by the motor for resetting. Electromechanical pressure actuators and brake control systems (ESP) are well known, and together they can form a braking system in a vehicle.

[0009] The ESP has valves, circular storage chambers and a pump to enable pressure build-up and reduction on a wheel-by-wheel basis.

[0010] The primary pressure regulator is located upstream of the ESP and, depending on the braking request, acts on the pistons of the (tandem) master cylinder (TMC) to build up pressure. The pressure regulator can also receive the braking request externally (by-wire).

[0011] When pressure is built up, the pressure regulator can also be operated in a controlled manner, but is additionally pushed back by the brake pressure and the return springs provided for this purpose.

[0012] A reset until the sniffer holes in the TMC are opened may always be necessary outside of a braking request.

[0013] The return spring in the pressure regulator takes up considerable space and always counteracts the pressure build-up.

[0014] DE 10 2011 112 957 describes a braking device

[0015] Disclosure of the invention

[0016] The present invention provides a method for actuating a mechanism in a brake booster device of a brake system according to claim 1 and a brake system according to claim 9.

[0017] Preferred further training is the subject of the subclaims.

[0018] Advantages of the invention The idea underlying the present invention is to provide a method for actuating a mechanism in a brake booster device and a braking system, wherein a function for resetting the mechanism of the brake booster device from a braking state can be achieved without a return spring.

[0019] The restoring force can be used to define a force for resetting the

[0020] Master brake cylinder and a gear unit for an electric motor, which can serve as an actuator of the master brake cylinder, and at the same time the force acting against a driver's foot in the backup (brake release) can be reduced.

[0021] According to the invention, in the method for actuating a mechanism in a brake booster device of a brake system, a determination is made as to whether, after a previous braking operation, the

[0022] Brake booster device a driver braking request has ended or whether there is no driver braking request at the brake booster device after a previous braking operation by the brake booster device by means of a control device of a vehicle system; a detection of an operational fault of the brake booster device by the control device; a detection of an operational fault of a pressure regulator by the control device, which is connected to the brake booster device or is present in it and is designed to determine a brake pressure and / or a reset pressure at a

[0023] Main brake cylinder device of the brake booster device; building up a predetermined minimum pressure in the

[0024] Master brake cylinder device by the vehicle system and thereby resetting the mechanism and by this a master brake cylinder into a neutral position with reduced or no braking effect on a braking element when the driver's braking request has ended or when there is no longer any driver's braking request, whereby the build-up of the minimum pressure is controlled by the control device of the vehicle system.

[0025] The malfunction may be due to faults in the electrical

[0026] It could be a fault in the electrical system / supply, the electronics / ECU / PC / ASICs, a fault in the engine control or the engine itself, or a fault in the mechanics, which can be detected and lead to shutdown.

[0027] The pressure regulator can be a component of the brake booster system or the vehicle system. The pressure regulator for a hydraulic serial (by-wire) braking system according to the invention can be a pressure / volume adjuster, which can be operated with pressure control, and an ESP system connected in series, which can also be operated with pressure control. The pressure / volume adjuster can be a plunger system, such as the brake booster components (primary actuator) themselves, while the ESP system can have a pump. For example, the pressure adjuster can be the primary actuator and the ESP system the backup actuator. The ESP system (which can also function as a pressure regulator) can determine the residual pressure in or at the master brake cylinder, then becomes active and pushes back the master brake cylinder and the brake booster mechanism.

[0028] The neutral position can correspond to a range for the position of the master brake cylinder in which the braking force on a brake can be reduced or nonexistent. Thus, the return spring can push the master brake cylinder from a braking position to the neutral position when the brake is to be released. The master brake cylinder can be connected to additional springs in the cylinder housing. The return spring can have a radius that is smaller than the radius of the cylinder housing, whereby the cylinder housing itself can have cylindrical symmetry relative to the main extension direction. The return pressure can be sufficient to push the master brake cylinder into the neutral position.

[0029] The control device of a vehicle system, in particular a vehicle stability system (ESP), can have a function, advantageously with program instructions, for controlling a pressure regulator of this vehicle (stability) system or a pressure regulator of the brake booster system and thus advantageously a pump for transporting a volume of hydraulic fluid. This function advantageously detects the failure of the pressure regulator or the pressure regulator during a braking operation. By utilizing the valves, accumulator chamber, and pump in the ESP, this function in the ESP initiates a volume flow towards the master brake cylinder and takes over the resetting of the pistons of the master brake cylinder. In a broader sense, the accumulator chamber can also be the wheel brake cylinder, which can briefly absorb more volume (and thus pressure) than necessary.

[0030] The mechanism may include a gearbox, an actuator, an electric motor and / or other components for moving the master brake cylinder.

[0031] According to a preferred embodiment of the method, the malfunction of the brake booster device involves the brake booster device resetting the mechanism to the neutral position. The primary actuator (pressure regulator as the brake force device itself) can be active during all braking operations that require a pressure buildup at all four wheels of the vehicle. For example, during normal partial braking by the driver without brake control interventions. A malfunction would then result in the actuator mechanism / motor no longer being able to return to the rest position with open sniffer bores after the end of the braking request, which could result in unwanted residual pressure remaining in the system.

[0032] According to a preferred embodiment of the method, a predetermined volume of hydraulic fluid is fed from a storage chamber for the hydraulic fluid into the master brake cylinder device by means of the vehicle system for resetting, thereby building up the minimum pressure.

[0033] The accumulator chamber and pump can be components of the vehicle system. The minimum pressure can be adaptively adjusted for the respective resetting action (partial or full resetting) or can be predefined.

[0034] According to a preferred embodiment of the method, the control device determines the existing volume of hydraulic fluid in the accumulator chamber prior to resetting and compares it with a predetermined operating volume. If the existing volume is less than the predetermined operating volume, the pump draws an additional volume to achieve the minimum pressure from a pre-chamber of the master brake cylinder into the accumulator chamber via sealing lips of a piston of the master brake cylinder. The additional volume is then pumped from the accumulator chamber into a pressure area of ​​the master brake cylinder. Theoretically, the amount of volume unintentionally trapped by the master brake cylinder is precisely sufficient to push it back far enough for the master brake cylinder to release the sniffer bores again.

[0035] With wheel brake cylinders, it's possible that a vacuum at the wheel brake cylinder will cause air to enter the brake circuit through the wheel seals. Therefore, it may be advisable to have more volume than required on the suction side of the pump to push the master cylinder pistons back to at least the position of the sniffer holes before applying vacuum at the wheel.

[0036] The predetermined operating quantity can be such a quantity / volume of hydraulic fluid that, depending on the specification, it can currently produce a braking effect or no braking effect (e.g. a reset).

[0037] The minimum pressure can be built up in the pressure range for resetting, for example by the pump.

[0038] According to a preferred embodiment of the method, after the additional volume has been at least partially pumped into the pressure area, the step is repeated at least once, after which the existing volume of hydraulic fluid in the storage chamber before resetting is determined and compared with a predetermined operating volume, and if the existing volume is less than the predetermined operating volume, an additional volume is sucked via the pump from a pre-chamber of the master brake cylinder into the storage chamber via sealing lips of a piston of the master brake cylinder to achieve the minimum pressure and is then pumped from the storage chamber into a pressure area of ​​the master brake cylinder. The repetition can be optional and is not mandatorily initiated. The function must always be started when the ESP detects an unwanted residual pressure.

[0039] According to a preferred embodiment of the method, the control device detects the presence of the driver's braking request via a pedal position and / or by determining a vehicle speed and / or via a driver interface.

[0040] According to a preferred embodiment of the method, the control device is a control device of a vehicle stability system.

[0041] According to a preferred embodiment of the method, the minimum pressure is sufficient to open a sniffer bore when resetting the master brake cylinder.

[0042] The ESP can advantageously detect whether or not there is a malfunction in the pressure regulator and / or the brake booster system.

[0043] Such detection can advantageously be achieved using known mechanisms such as network monitoring or the forwarding and detection of an electrical signal from the pressure regulator and / or the brake booster device.

[0044] For this purpose, the ESP can advantageously check whether there is a braking request, which can be possible via an interface, such as a signal interface in the vehicle and / or in the ESP.

[0045] In the event of a braking request, the ESP's task can be to build up a certain pressure at the wheels (wheel brakes) as a backup for the brake booster. This function can be activated when there is no braking request, but it cannot be ruled out that residual pressure may still be present in the braking system and / or the ESP. The ESP function can be activated and then pump a volume (of hydraulic fluid) towards the master brake cylinder (e.g., a tandem master brake cylinder TMC) to build up pressure against the master brake cylinder pistons if the sniffer bores have not yet opened.

[0046] If there is too little volume in the ESP, the ESP can initially draw volume through the sealing lips of the master brake cylinder using a pump, which can act like a check valve. The HSV (high-pressure switching valve) allows the ESP to draw volume from the TMC / reservoir after opening and is open while the USV is closed (the switching valve allows the ESP to direct volume drawn from the reservoir to the wheels or to retain it at the wheels and / or in the storage chamber). The EVs and AVs can also be open, but not simultaneously. Closed inlet valves (EV) at the wheels prevent further pressure buildup at the wheel (typically during ABS braking).

[0047] It may be that EVs are open and AVs are closed, in which case the pump can deliver volume to the wheels.

[0048] It may be that EVs are closed, AVs are open and the volume then automatically flows into the storage chamber or the pump sucks from the storage chamber and delivers volume to the master brake cylinder because AVs can be closed and USVs open.

[0049] They also allow the wheel volume to flow into the storage chamber or to the pump when the outlet valves (AVs) are closed or open. The valves can be switched sequentially.

[0050] First, the pump can deliver volume to the wheels through open EVs. Then the pump can be turned off, the EVs close, and the AVs open. The pump now delivers volume from the wheels and the storage chamber toward the TMC. Volume control can be advantageously achieved using a model (as a program instruction of the function in the control unit) that can know the history of the measured pressure and pumps, as well as valve activity.

[0051] A certain volume can be temporarily stored in the storage chamber.

[0052] If the accumulator chamber is at least partially full, the ESP can begin to return a volume to the master cylinder. For this purpose, the HSV and the EVs can be closed to direct the volume from the accumulator chamber to the ESP. While the master cylinder's sniffer holes are closed, pressure can build up, which resets the pistons and the underlying mechanism, including the motor for the mechanism. If necessary (e.g., if the volume from the accumulator chamber is too low), one or more of the preceding steps can be repeated to ensure that the sniffer holes are open.

[0053] The method according to the invention can be used in a braking system consisting of ESP and an upstream pressure regulator. A prerequisite may be that ESP can determine that residual pressure does not simultaneously represent a braking request. This is the case, for example, with a decoupled brake-by-wire system.

[0054] According to the invention, the braking system comprises a brake booster device and a control device of a vehicle system, wherein the brake booster device is connected to the control device and can be connected to a pressure regulator or comprises a pressure regulator, wherein the control device is designed to determine whether a driver braking request has ended after a previous braking operation by the brake booster device or whether no driver braking request is present at the brake booster device after a previous braking operation by the brake booster device; to detect whether there is an operational malfunction of the brake booster device;to detect whether there is an operational malfunction of a pressure regulator, wherein the pressure regulator is connected to the brake booster device or is comprised thereof and is designed to build up a brake pressure and / or a reset pressure at a master brake cylinder device of the brake booster device; and to build up a predetermined minimum pressure in the master brake cylinder device by means of the vehicle system and thereby cause the mechanism and, through this, a master brake cylinder to be reset to a neutral position with reduced or no braking effect on a braking element when the driver's braking request has ended or when there is no longer any driver's braking request, wherein the build-up of the minimum pressure is controllable by the control device of the vehicle system;

[0055] According to a preferred embodiment of the braking system, the control device comprises a control device of a vehicle stability system.

[0056] The braking system can also be characterized by the features and advantages mentioned in connection with the method and vice versa.

[0057] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

[0058] Short description of the drawings

[0059] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing.

[0060] They show:

[0061] Fig. 1 is a schematic representation of a braking system according to an embodiment of the present invention;

[0062] Fig. 2 shows a block diagram of process steps of the process for

[0063] Actuating a mechanism in a brake booster device in a braking system according to an embodiment of the present invention;

[0064] In the figures, the same reference symbols denote the same or functionally identical elements.

[0065] Fig. 1 shows a schematic representation of a braking system according to an embodiment of the present invention.

[0066] Shown is a braking system 1 with a brake booster device 10 and a control device SE of a vehicle system ESP, wherein the brake booster device 10 is connected to the control device SE and is connectable to a pressure regulator or comprises a pressure regulator (this may refer to the brake booster device 10 or the ESP or another pressure regulator), wherein the control device SE is configured to determine whether a driver braking request has ended after a previous braking operation by the brake booster device 10 or whether there is no driver braking request at the brake booster device 10 after a previous braking operation by the brake booster device 10 by means of the control device SE; to detect whether there is an operational malfunction of the brake booster device 10; to detect whether there is an operational malfunction of a pressure regulator,wherein the pressure regulator is connected to the brake booster device and is configured to build up a braking pressure and / or a reset pressure at a master brake cylinder device HZE of the brake booster device 10; and to build up a predetermined minimum pressure in the master brake cylinder device HZE via the vehicle system ESP and thereby cause the mechanism and, through this, a master brake cylinder to be reset to a neutral position with reduced or no braking effect on a braking element when the driver's braking request has ended or when there is no longer any driver's braking request, wherein the build-up of the minimum pressure is controllable by the control device of the vehicle system. The ESP a detects the failure of the pressure regulator b. This can happen, for example, via known mechanisms such as network monitoring g or an electrical signal g. The ESP a can check whether a braking request is present. This is possible via a signal interface,This is possible, for example, with the SE control unit. When a braking request is made, the ESP can be tasked with building up pressure in the wheels as a backup booster for the brake booster. This function can be activated when there is no braking request, but it cannot be ruled out that residual pressure remains in the system. The ESP function can be activated and aims to pump volume toward the TMC (HZE, f) to build up pressure against the TMC pistons if the sniffer holes have not yet been opened. If there is too little volume in the ESP, it first draws volume via the TMC's sealing lips, which act like a check valve, using pump e.

[0067] The HSV h is open and the USV i is closed. The EVs j and AVs k are also open. The volume balance can be achieved using a model that knows the history of the measured pressure and the pumps e and valve activities (h, i, j, k). The volume is temporarily stored in the storage chamber d. Once the storage chamber d is at least partially full, the ESP begins to pump volume back towards the TMC f. For this purpose, the HSV h and the EVs j are closed in order to pump the volume from the storage chamber towards the ESP. As long as the sniffer holes are closed, pressure will build up which resets the pistons and the underlying mechanics and motor.

[0068] Fig. 2 shows a block diagram of method steps of the method for actuating a mechanism in a brake booster device in a brake system according to an embodiment of the present invention.

[0069] In the method for actuating a mechanism in a brake booster device of a braking system, a determination S1 is made as to whether a driver's braking request has ended after a previous braking operation by the brake booster device or whether there is no driver's braking request at the brake booster device after a previous braking operation by the brake booster device by means of a control device of a vehicle system; a detection S2 of an operational malfunction of the brake booster device by the control device; a detection S3 of an operational malfunction of a pressure regulator by the control device, which is connected to the brake booster device and is designed to build up a braking pressure and / or a reset pressure at a master brake cylinder device of the brake booster device;a build-up S4 of a predetermined minimum pressure in the master brake cylinder device by the vehicle system and thereby resetting the mechanism and, by this, a master brake cylinder to a neutral position with reduced or no braking effect on a braking element when the driver's braking request has ended or when there is no longer any driver's braking request, wherein the build-up of the minimum pressure is controlled by the control device of the vehicle system;

[0070] Although the present invention has been fully described above using the preferred embodiment, it is not limited thereto but can be modified in many ways.

Claims

Claims 1. Method for actuating a mechanism in a brake booster device (10) in a brake system (1), comprising the steps: Determine (Sl) whether a driver's brake request has ended after a preceding braking operation by the brake booster device (10) or whether there is no driver's brake request at the brake booster device (10) after a preceding braking operation by the brake booster device (10) by means of a control unit (SE) of a vehicle system (ESP); Detection (S2) of a malfunction of the brake booster device (10) by the control unit (SE); Detection (S3) of a malfunction of a pressure regulator by the control unit (SE) which is connected to or encompassed by the brake booster unit (10) and is designed to build up a brake pressure and / or a return pressure at a master brake cylinder unit (HZE) of the brake booster unit (10); Building up (S4) a predetermined minimum pressure in the master brake cylinder assembly (HZE) by the vehicle system (ESP) and thereby resetting the mechanism and by this of a master brake cylinder to a neutral position with reduced or no braking effect on a brake element when the driver's braking request has ended or when there is no longer a driver's braking request, wherein the building up of the minimum pressure is controlled by the control unit (SE) of the vehicle system (ESP).

2. Method according to claim 1, wherein the malfunction of the brake booster device (10) relates to a return of the mechanics to the neutral position by the brake booster device (10).

3. Method according to claim 1 or 2, wherein a predetermined volume of hydraulic fluid is used to reset the vehicle system (ESP). A hydraulic fluid is pumped from a storage chamber into the master brake cylinder assembly (HZE) to build up the minimum pressure. The method according to claim 3, wherein the control device (SE) determines the volume of hydraulic fluid present in the storage chamber before resetting and compares it to a predetermined operating volume. If the present volume is less than the predetermined operating volume, an additional volume is drawn from a pre-chamber of the master brake cylinder into the storage chamber via the pump through the sealing lips of a piston of the master brake cylinder to achieve the minimum pressure. This additional volume is then pumped from the storage chamber into a pressure section of the master brake cylinder.A method according to claim 4, wherein, after the additional volume has been at least partially pumped into the pressure range, the step is repeated at least once, whereby the volume of hydraulic fluid present in the accumulator chamber is determined before resetting and compared with a predetermined operating volume, and if the volume present is less than the predetermined operating volume, an additional volume to achieve the minimum pressure is drawn via the pump from a pre-chamber of the master brake cylinder into the accumulator chamber via sealing lips and subsequently pumped from the accumulator chamber into the pressure range of the master brake cylinder. A method according to any one of claims 1 to 5, wherein the control unit (SE) detects the presence of the driver's braking request via a pedal position and / or by determining a vehicle speed and / or via a driver interface.A method according to any one of claims 1 to 6, wherein the control device is a control device of a vehicle stability system. A method according to any one of claims 1 to 7, wherein the minimum pressure is sufficient to create a sniffer bore when the master brake cylinder is reset. to open. Brake system (1) with a brake booster device (10) and a control unit (SE) of a vehicle system (ESP), wherein the brake booster device (10) is connected to the control unit (SE) and is connectable to a pressure regulator or includes a pressure regulator, wherein the control unit (SE) is configured to determine whether, after a preceding braking operation by the brake booster device (10), a driver's braking request has ended or whether there is no driver's braking request at the brake booster device (10) after a preceding braking operation by the brake booster device (10) by means of the control unit (SE); to detect whether there is a malfunction of the brake booster device (10);to detect whether a malfunction of the pressure regulator is present, wherein the pressure regulator is connected to or encompassed by the brake booster assembly and is configured to build up a brake pressure and / or a return pressure at a master brake cylinder assembly (HZE) of the brake booster assembly (10); and to build up a predetermined minimum pressure in the master brake cylinder assembly (HZE) by the vehicle system (ESP) and thereby cause the mechanism of a master brake cylinder to return to a neutral position with reduced or no braking effect at a brake element when the driver's braking request has ended or when there is no longer a driver's braking request, wherein the build-up of the minimum pressure is controllable by the control unit of the vehicle system. Brake system (1) according to claim 9, wherein the control unit (SE) comprises a control unit (SE) of a vehicle stability system.

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