Brake system, vehicle, and method for operating a brake system

Abstract

The invention relates to a brake system comprising an actuating element, in particular a hand or foot lever, and a hydraulic system which has at least one fluid circuit, wherein the actuating element is operatively connected to the fluid circuit in order to directly or indirectly generate a brake pressure, the actuating element can be moved along a lever path in order to generate the brake pressure, and the brake system has a compensating device which is designed to adjust the internal volume of the fluid circuit in such a way that the lever path-based brake pressure remains constant during operation.

Description

[0001] Braking system, vehicle and method for operating a braking system

[0002] The present invention relates to a braking system, a vehicle and a method for operating a braking system.

[0003] During operation, braking systems, for example on motorcycles, and their components, in particular the brake pistons, the brake caliper and the brake fluid, become very hot. This causes the internal volume of the closed system in which the brake fluid is located to change relative to the volume of the brake fluid itself. At the same time, the behavior of the elastomer seal on the brake piston also changes with increasing system temperatures, etc. Due to these mechanisms, a different lever travel on the brake lever must be selected at high braking system temperatures than at low system temperatures to achieve the same braking effect. This change in lever travel is disadvantageous for the rider because it impairs the modulation of the brake. The impression of quality deteriorates and confidence in the braking system suffers.

[0004] It is therefore an object of the present invention to provide a braking system, a vehicle and a method for operating a braking system, wherein a consistent braking behavior is to be ensured even at high and extremely high system temperatures.

[0005] This object is achieved by a braking system according to claim 1, a vehicle according to claim 8 and a method according to claim 9. Further advantages and features emerge from the subclaims as well as the description and the attached figures.

[0006] According to the invention, a braking system comprises an actuating element, in particular a hand or foot lever / foot pedal, and a hydraulic system which comprises at least one fluid circuit, wherein the actuating element is operatively connected to the fluid circuit for directly or indirectly generating a braking pressure, wherein the actuating element can be moved along a lever travel to generate the braking pressure, and wherein the braking system, in particular the fluid circuit, has a compensation device which is designed to adjust or change the internal volume of the fluid circuit such that the lever travel-dependent braking pressure remains constant during operation. During operation, the braking system or its components, in particular, for example, the brake pistons, the brake caliper and the brake fluid (brake fluid or hereinafter also simply referred to as fluid), become very hot.This causes the internal volume of the closed system containing the fluid to change relative to the fluid's own volume. In addition, the behavior of the elastomer seal on the brake piston also changes with rising system temperatures, etc. Due to these mechanisms, a different lever travel on the brake lever is typically required at high brake system temperatures than at low system temperatures to achieve the same braking power or braking effect. The compensation device advantageously enables the same lever travel on the brake lever to achieve a certain braking power or braking effect, even at high system temperatures, as at low temperatures. The driver can therefore rely on the brake or braking system and does not have to expect that it will react or operate differently at different temperatures.

[0007] The fluid circuit comprises a wide variety of components, such as lines, seals, valves, fluid reservoirs, pumps, etc. All of the aforementioned components expand when the temperature increases and shrink when the temperature drops again. The internal volume of the fluid circuit, where the internal volume refers in particular to the volume that comes into contact with the fluid, in particular the brake fluid, changes its size. In addition, the fluid volume itself also changes depending on the temperature. The compensation device is advantageously designed to change or adjust the internal volume of the fluid circuit, in particular the line volume, so to speak, in such a way that the lever travel-dependent fluid pressure remains constant during operation.If, for example, the internal volume of the fluid circuit increases by 10% due to temperature and the volume of the brake fluid by 5%, the compensation device can expediently act on the internal volume of the fluid circuit in such a way that the different thermal expansions / shrinkages can be compensated. This compensation is advantageously achieved in such a way that the lever-travel-dependent brake pressure remains constant regardless of the system temperature.

[0008] With regard to the at least one fluid circuit, it should be noted that the hydraulic system can also have multiple fluid circuits. For example, there are brake systems that have a control circuit and a wheel circuit. The control circuit is directly connected to the actuating element, while the wheel circuit is the fluid circuit that is operatively connected to the brake piston(s) and in which the actual brake pressure is built up. In addition, there are also brake systems that have only one fluid circuit and, for example, operate with a conventional brake booster, etc. Advantageously, the invention can be implemented for a wide variety of brake systems. The existing hydraulic system only needs to be examined to determine the extent of its volume change. If this change is known, it can be compensated for.

[0009] According to one embodiment, the compensation device comprises a compensation element designed to influence the internal volume of the fluid circuit through its own volume change and / or through a change in position within the fluid circuit. The compensation element expediently acts directly on the fluid or on the fluid volume. The compensation element is expediently directly or at least closely connected to the fluid. In particular, the compensation element is advantageously thermally connected to the braking system in such a way that the system temperature relevant for the volume expansion of the hydraulic system or the fluid circuit can be absorbed or assumed.

[0010] According to one embodiment, the at least one compensation element is a body which is arranged fixedly or loosely at least in some regions within the fluid circuit, preferably, for example, within the line system of the fluid circuit. The body is, for example, an elastomer body which changes its volume depending on the fluid temperature. The elastomer body can be fixedly connected to a brake component, for example in the brake caliper, or can be located loosely in the fluid, in particular in the brake fluid. If the internal volume of the hydraulic system increases at higher temperatures, the volume of the aforementioned compensation element also increases at the same time, whereby the effective volume change is compensated again, depending on the design of the compensation element, since the compensation element is arranged entirely or at least in some regions within the hydraulic system, in particular in the line system.When designing the compensation element, it is important, as already indicated, to take into account the change in volume of the fluid. According to one embodiment, the at least one compensation element is an adjusting element, in particular a piston or a diaphragm, which is arranged to be movable or, in particular as such, displaceable within the fluid circuit or relative thereto and is designed to influence the internal volume of the fluid circuit. The piston can, for example, move into and out of the fluid circuit, in particular into the line system, and thus influence its internal volume, in particular increasing or decreasing it. The adjusting element does not have to be arranged, or at least not entirely, within the fluid circuit. A diaphragm can act in a similar way, acting on the fluid to increase or decrease the internal volume of the fluid circuit.

[0011] According to one embodiment, the compensation device comprises an auxiliary element designed to effect the position change of the adjustment element via thermal expansion or shrinkage. This expediently enables an automatic change in the position or position of the adjustment element without the need for complex mechanics or control or regulation technology. Only the "behavior" of the auxiliary element needs to be designed appropriately.

[0012] According to one embodiment, the compensation element is a movably mounted piston, which can be moved over the auxiliary element, in particular a bimetal, depending on the temperature. According to one embodiment, the braking system comprises a brake caliper, wherein the compensation device is arranged or formed in or near the brake caliper. In the case of a drum brake, the compensation device is preferably arranged in or near the wheel cylinder. This component is intended to spread the brake shoes and press them against the brake drum.

[0013] The compensation device, or in particular the compensation element, is expediently thermally connected to the hydraulic system in such a way that the temperature decisive for the volume expansion of the fluid circuit or the fluid can be absorbed as effectively as possible. The characteristic curve of the volume change of the compensation element, or the volume change caused by the compensation device for the absorbed temperature, is expediently as close as possible to the volume change of the fluid circuit, in particular its internal volume and the fluid volume. The aforementioned braking system is suitable for motor vehicles, such as passenger cars, or in particular, motorcycles, such as scooters or motorbikes, especially single- or multi-track tilting vehicles. The braking system is also suitable for bicycles, whether with or without an (electric) auxiliary motor.This braking system can be particularly useful for sports bikes, such as mountain bikes, which are used for downhill riding. The braking system can be a system with one or more disc brakes. It can also be a system with one or more drum brakes. In passenger cars, especially small cars, mixed systems are also common.

[0014] The invention also relates to a vehicle comprising at least one braking system according to the invention. Possible vehicles have already been mentioned. In particular, vehicles of the type in question are motorcycles, especially tilting vehicles, which include both single- and multi-track vehicles, in particular LMW (Leaning Multiwheel) vehicles, trikes, quads, etc. Motorcycles used for sport riding, in particular, but also touring motorcycles, which, for example, must tackle long mountain pass descents, can benefit from such a braking system.

[0015] The invention also relates to a method for operating a braking system, wherein the braking system comprises at least one actuating element, in particular a hand or foot lever (or a foot pedal), and a hydraulic system which has at least one fluid circuit, wherein the actuating element is operatively connected to the fluid circuit for directly or indirectly generating a braking pressure, and wherein the method comprises the steps:

[0016] - Provision of a compensation element in the fluid circuit which can change its volume or position or orientation depending on the temperature in such a way that the lever travel-dependent fluid pressure remains constant.

[0017] In particular, the compensation element can be used to conveniently compensate for a change in the volume of the fluid circuit and the fluid volume itself.

[0018] The procedure conveniently comprises the following steps:

[0019] - Determine the effective volume change of the hydraulic system;

[0020] - Adjusting the operation of the compensation element depending on the effective volume change. The effective volume change refers to the actual or effective volume change of the entire system, in particular the change in the volume of the fluid circuit as well as the change in the fluid volume itself. The compensation element or compensation device expediently acts on the internal volume in such a way that the lever-travel-dependent brake pressure remains constant during operation. This means, in particular, that the driver does not have to apply a different lever travel to achieve the same braking effect at high temperatures than at low temperatures. The system behavior is expediently always the same and independent of the temperature, thus ensuring optimal controllability.

[0021] The advantages mentioned in connection with the braking system apply analogously and accordingly to the process, and vice versa.

[0022] Further advantages and features will become apparent from the following description of schematic embodiments of a braking system with reference to the attached figures.

[0023] They show:

[0024] Fig. 1: a sketch of a first embodiment of an inventive

[0025] braking system;

[0026] Fig. 2: a sketch of another embodiment of an inventive

[0027] braking system.

[0028] Fig. 1 schematically shows a hydraulic system 20, comprising a fluid circuit 22, with which an actuating element 10, in this case a hand lever, for example of a motorcycle, is operatively connected such that a brake pressure p can be generated. A fluid is located in the fluid circuit 22. In this case, a compensation element 30 is arranged in the fluid circuit 22. The double arrows indicate that the compensation element 30 changes its volume depending on the temperature. The fluid located in the fluid circuit 22 also changes its volume with the temperature. With appropriate design of the compensation element 30, it can be expediently achieved that the lever-travel-dependent brake pressure can be kept constant during operation, regardless of the prevailing temperature. Fig. 2 shows a further embodiment of a brake system according to the invention, the basic structure of which is already known from Fig. 1.The compensation element 30 is designed here as an adjusting element, for example as a piston, which can move into and out of the fluid circuit 22, whereby its internal volume can be influenced.

[0029] List of reference symbols

[0030] 10 Actuating element, hand or foot lever

[0031] 20 Hydraulic system 22 Fluid circuit

[0032] 30 Compensation element p brake pressure

Claims

Claims 1. A braking system comprising an actuating element (10), in particular a hand or foot lever, and a hydraulic system (20) which has at least one fluid circuit, wherein the actuating element (10) is operatively connected to the fluid circuit (22) for directly or indirectly generating a braking pressure (p), wherein the actuating element (10) can be moved along a lever travel to generate the braking pressure, and wherein the braking system has a compensation device which is designed to adjust the internal volume of the fluid circuit (22) such that the lever travel-dependent braking jerk (p) remains constant during operation.

2. Braking system according to claim 1, wherein the compensation device comprises at least one compensation element (30) which is designed to influence the internal volume of the fluid circuit (22) by its own volume change and / or by a position change.

3. Braking system according to claim 2, wherein the at least one compensation element (30) is a body which is arranged fixedly or loosely at least in regions within the fluid circuit (22).

4. Brake system according to one of claims 2 to 3, wherein the at least one compensation element (30) is an adjusting element, in particular a piston or a membrane, which is movably arranged within the fluid circuit (22).

5. Braking system according to claim 4, wherein the compensation device comprises an auxiliary element which is designed to effect the change in position of the adjusting element via thermal expansion or thermal shrinkage.

6. Brake system according to one of claims 4 to 5, wherein the compensation element (30) is a movably mounted piston which can be moved over the auxiliary element, in particular a bimetal, depending on the temperature.

7. Braking system according to one of the preceding claims, comprising at least one brake caliper or wheel cylinder, and wherein the compensation device is arranged or formed in or in the region of the brake caliper or the wheel cylinder.

8. A vehicle comprising a braking system according to any one of the preceding claims.

9. A method for operating a braking system, wherein the braking system has at least one actuating element (10), in particular a hand or foot lever, and a hydraulic system (20) which has at least one fluid circuit (22), wherein the actuating element (10) is operatively connected to the fluid circuit (22) for directly or indirectly generating a braking pressure, comprising the step: - Providing a compensation element (30) in the fluid circuit (22) which can change its volume or position depending on the temperature in such a way that the lever travel-dependent fluid pressure remains constant.

10. The method according to claim 9, comprising the steps: - determining the effective volume change of the fluid circuit (22); - Adjusting the operation of the compensation element (30) depending on the effective volume change.

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