Brake device for a vehicle hydraulic brake system and method for operating a vehicle hydraulic brake system - Patents.com

Abstract

The invention relates to a brake device for a hydraulic brake system of a vehicle, comprising a piston (10) adjustable in a storage volume (12) dividing the storage volume (12) into a first partial volume (12a) and a second partial volume (12b), a system-specific or system-external brake cylinder (16) is coupled or can be coupled to the first partial volume (12a) and a system-specific or system-external wheel brake cylinder (18) is coupled or can be coupled to the second partial volume (12b), and further comprising a bypass line (20), a non-return valve (22) arranged in the bypass line (20) being switchable by the piston (10) such that the non-return valve (20) is in an open state at least when the piston (10) is in a normal position and is switched to a closed state by the piston (10) being adjusted by at least a minimum adjustment distance from the normal position. Furthermore, the invention relates to a method for operating a hydraulic brake system of a vehicle.

Description

[Technical Field]

[0001] The present invention relates to a brake device for a vehicle hydraulic brake system and to a vehicle hydraulic brake system.Furthermore, the present invention relates to a method for operating a vehicle hydraulic brake system. [Background technology]

[0002] Patent Document 1 describes a vehicle brake system having a hydraulic actuator device, in which a piston of the actuator device, adjustable by a motor of the actuator device, divides a reservoir chamber of the actuator device into a first partial volume and a second partial volume. The first partial volume of the reservoir chamber on a first side of the adjustable piston is hydraulically connected to a brake cylinder so that brake fluid can be transferred between the brake cylinder and the first partial volume of the reservoir upon increasing or decreasing the operation of a brake operating element connected to the brake cylinder. The second partial volume of the reservoir chamber on a second side of the piston is hydraulically connected to a wheel brake cylinder, thereby allowing brake fluid to be transferred between the second partial volume of the reservoir chamber and the wheel brake cylinder. Furthermore, the wheel brake cylinder is hydraulically connected to a bypass, which communicates with the first partial volume of the reservoir chamber when the adjustable piston of the actuator device is in its normal position, thereby allowing brake fluid to be transferred between the brake cylinder and the wheel brake cylinder via the bypass. The adjustable piston of the actuator device is held in its normal position by a spring. However, the adjustable piston of the actuator device can be adjusted from its normal position against the force of a spring by the motor of the actuator device, so that the hydraulic connection between the brake cylinder and the wheel brake cylinder via the bypass is interrupted from the time of adjustment by at least a predetermined minimum adjustment distance of the piston from the normal position. After the interruption of the hydraulic connection between the brake cylinder and the wheel brake cylinder, the brake pressure present in the wheel brake cylinder can be adjusted by further sliding of the adjustable piston of the actuator device.

[0003] However, the operation of the actuator device of the brake system of the patent document described in the preceding paragraph requires the formation of an adjustable piston having a first area adjacent to a first partial volume of the reservoir on a first side of the piston that is greater than a second area adjacent to the second partial volume of the reservoir on a second side of the piston. Additionally, the piston fluid-tightly seals the first partial volume of the reservoir from the second partial volume of the reservoir only when a first pressure present in the first partial volume is greater than a second pressure prevailing in the second partial volume. This means that to adjust the piston from its normal position, the motor of the actuator device must forcefully overcome both the pressure difference between the first pressure and the second pressure and the area difference between the first area on the first side of the piston and the second area on the second side of the piston. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 3124344 Summary of the Invention

[0005] The present invention provides a brake device for a vehicle hydraulic braking system having the features of claim 1, a vehicle hydraulic braking system having the features of claim 9, and a method for operating a vehicle hydraulic braking system having the features of claim 10.

[0006] The present invention provides an advantageous possibility for ensuring a desired brake pressure in at least one wheel brake cylinder of a vehicle. A vehicle can be understood as both a vehicle with only two wheels and a vehicle with more than two wheels. The vehicle can be a vehicle without an electric drive or a vehicle equipped with a motor drive. The present invention can be used, for example, in bicycles (powered by muscle power), electric two-wheelers, electric bicycles, motorcycles, as well as in motor vehicles, such as cars or freight vehicles.

[0007] The present invention provides a braking device or hydraulic braking system in which, when the respective adjustable pistons are in their normal positions, brake fluid can be transferred between a brake cylinder associated with an adjacent first partial volume and a wheel brake cylinder associated with an adjacent second partial volume, but this transfer of brake fluid is prevented by the pistons being adjusted by at least a predetermined minimum adjustment distance from their normal positions. However, unlike the aforementioned prior art (which uses a first pressure in the first partial volume of the piston and a second pressure in the second partial volume of the piston), the adjustable pistons of the braking device according to the present invention (which uses the same first pressure in the first partial volume of the piston and the same second pressure in the second partial volume of the piston) can be adjusted by the predetermined minimum adjustment distance from their normal positions with less force and significantly reduced energy consumption.

[0008] Therefore, the brake device or corresponding hydraulic brake system according to the present invention has significantly improved performance and significantly reduced energy consumption compared to the prior art described above. In addition, the present invention achieves the elimination of the weaknesses of the prior art while maintaining the functional scope and all the advantages of the prior art.

[0009] The implementation of the present invention does not require any active components other than the check valve, therefore the technical implementation of the present invention is relatively cheap and does not / only increases the required space.

[0010] In an advantageous embodiment of the brake device, the piston has a cylindrical base body and a protruding ring portion at the base body, the ring portion of the piston fluid-tightly sealing a first partial volume of the storage volume located on a first side of the ring portion from a second partial volume of the storage volume located on a second side of the ring portion, and the cylindrical base body extends from a first notch located on the first side of the ring portion through the storage volume to a second notch located on the second side of the ring portion. Therefore, the cylindrical base of the piston can also be referred to as a consistent piston rod. Accordingly, the piston can be referred to as a consistent piston. Based on the advantageous configuration of the piston described herein, the force required to adjust at least a minimum adjustment distance from the normal position of the piston when a first pressure is present in the first partial volume and a second pressure is present in the second partial volume is significantly smaller than in the aforementioned prior art, which uses the same first pressure in the first partial volume of the piston and the same second pressure in the second partial volume of the piston. This contributes to additionally reducing the energy consumption of the braking device embodiments described herein.

[0011] In particular, the piston is guided by at least one guide pin, in this way preventing undesired rotation of the piston that is adjusted by at least a minimum adjustment distance from the normal position or that has been adjusted back to the normal position.

[0012] In a preferred embodiment of the braking device, the bypass line and check valve are formed in the piston. Incorporation of the bypass line and check valve into the piston allows the space requirements of the braking device embodiments described herein to be reduced while maintaining the functional range of the braking device.

[0013] Advantageously, the check valve formed in the piston can be held open by a plunger that protrudes into an opening in a piston that is fixedly arranged in the brake device when the piston is in its normal position, while the piston, which is adjusted by at least a minimum adjustment distance from the normal position, is adjusted relative to the plunger so that the check valve is switched to its closed state. The use of a fixedly arranged / fixed plunger allows for a relatively simple construction of the piston, including a check valve integrated therein and a bypass line running through the piston.

[0014] For example, a check valve formed in a piston may include a valve body and a spring device, wherein the valve body is held away from a constriction formed in the opening against the force of the spring device by a plunger protruding into an opening in the piston when the piston is in its normal position, while the force of the spring device urges the valve body toward the constriction from at least a minimum adjustment distance of the piston from the normal position, such that mechanical contact between the valve body and the constriction fluid-tightly seals an outer portion of the opening located on a first side of the constriction from an inner portion of the opening located on a second side of the constriction. The piston configurations described herein can be produced relatively inexpensively.

[0015] In particular, the bypass line formed in the piston may include a first radial contact hole through the piston extending from a first subvolume of the reservoir volume to an inner portion of the opening, and a second radial contact hole through the piston extending from an outer portion of the opening to a second subvolume of the reservoir volume. The configurations of the bypass line extending through the piston described herein are easily realized.

[0016] In an alternative embodiment of the braking device, a pin is attached to the piston, the pin being adjustable with the piston, the pin holding the check valve open at least when the piston is in its normal position, while the check valve is switched to its closed state by the pin being adjusted together with the piston being adjusted by at least a minimum adjustment distance from its normal position. The forms of braking device described herein can also be easily implemented in construction.

[0017] The aforementioned advantages are also ensured in a hydraulic brake system of a vehicle comprising such a brake device, a brake cylinder coupled to a first partial volume of the storage volume of the brake device, and a wheel brake cylinder coupled to a second partial volume of the storage volume.

[0018] Furthermore, the implementation of a corresponding method for operating a vehicle hydraulic braking system also provides the above-mentioned advantages.It should be explicitly mentioned that a method for operating a vehicle hydraulic braking system according to the above-described embodiments of the brake device can be developed. [Brief explanation of the drawings]

[0019] [Figure 1a] 1 is a schematic diagram of a first embodiment of a brake device. [Figure 1b] 1 is a schematic diagram of a first embodiment of a brake device. [Figure 2a] FIG. 4 is a schematic diagram of a second embodiment of a brake device. [Figure 2b] FIG. 4 is a schematic diagram of a second embodiment of a brake device. [Figure 3] 1 is a flow chart illustrating one embodiment of a method for operating a hydraulic braking system of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0020] Other features and advantages of the present invention will be explained below with reference to the accompanying drawings.

[0021] 1a and 1b show a schematic diagram of a first embodiment of a braking device.

[0022] The braking device described below may / can be used as part of a hydraulic braking system of a vehicle. The applicability of the braking device is not limited to a specific braking system type. A vehicle equipped with the braking device can optionally be a vehicle with only two wheels or a vehicle with more than two wheels. A vehicle can also be understood as a vehicle without an electric drive, such as a (muscle-powered) bicycle. However, the vehicle can also be a vehicle equipped with a motor drive, such as an electric bicycle, a motorcycle, or a motor vehicle, in particular a car or a freight vehicle.

[0023] The brake system shown schematically in FIGS. 1a and 1b has a piston 10 that is adjustable within a reservoir volume 12 of the brake system by actuation of a motor 14. The piston 10 divides the reservoir volume 12 into a first partial volume 12a and a second partial volume 12b. A brake cylinder 16 is hydraulically coupled or connectable to the first partial volume 12a of the reservoir volume 12, i.e., to a port 12c of the first partial volume 12a and / or to a first line component 15a that communicates with the first partial volume 12a. The brake cylinder 16 can be an inherent or external brake cylinder 16. The brake cylinder 16 can be understood as a hydraulic device in which a brake operating element can be arranged or arranged so that brake fluid is forced out or drawn in from the brake cylinder 16 upon increasing or decreasing actuation of the brake operating element. The brake cylinder 16 can be, for example, a master brake cylinder. The brake operating element can be understood, in particular, as a brake pedal or a handbrake lever. The brake cylinder 16 is connectable / connected to the first partial volume 12a of the storage volume 12 so that brake fluid is transferable / transferable between the brake cylinder 16 and the first partial volume 12a.

[0024] A wheel brake cylinder 18 is (hydraulically) coupled or connectable to the second partial volume 12b of the storage volume 12, i.e., to the port 12d of the second partial volume 12b and / or to the second line component 15b that communicates with the second partial volume 12b. Although this is not shown in Figures 1a and 1b, in addition to the wheel brake cylinder 18, at least one further (not shown) wheel brake cylinder can be / can be connected accordingly to the second partial volume 12b. The (at least one) wheel brake cylinder 18 can be understood as a system-specific wheel brake cylinder 18 or a system-external wheel brake cylinder 18. The (at least one) wheel brake cylinder 18 can be / is connectable to the second partial volume 12b such that brake fluid can / is transferred between the second partial volume 12b and the (at least one) wheel brake cylinder 18.

[0025] The brake system also includes a bypass line 20 / bypass so that brake fluid can be transferred from the first partial volume 12a and / or the brake cylinder 16 associated with the first partial volume via a bypass line 20 to the second partial volume 12b and / or the (at least one) wheel brake cylinder 18 associated with the second partial volume via the bypass line 20 when at least the piston 10 is in the so-called normal position. The bypass line 20 can extend, for example, from the first line component 15a to the second line component 15b. FIG. 1a shows the brake system with the piston 10 in the normal position. As long as brake fluid can be transferred from the first partial volume 12a and / or the brake cylinder 16 associated with the first partial volume via the bypass line 20 to the second partial volume 12b and / or the (at least one) wheel brake cylinder 18 associated with the second partial volume, the first pressure p1 present in the first partial volume 12a is equal to the second pressure p2 prevailing in the second partial volume 12b.

[0026] A check valve 22 is arranged / formed in the bypass line 20, which check valve 22 is switchable / switchable by the piston 10 in an open state at least when the piston 10 is in a normal position and is switched to a closed state by the piston 10 being adjusted by at least a predetermined minimum adjustment distance Δx from the normal position. The advantageous arrangement and form of the check valve 22 switchable by the piston 10 therefore ensures that a transfer of brake fluid from the first partial volume 12a and / or the brake cylinder 16 associated with the first partial volume, which is possible when the piston 10 is in a normal position, to the second partial volume 12b and / or the (at least one) wheel brake cylinder 18 associated with the second partial volume via the bypass line 20 is prevented by the piston 10 being adjusted by at least a predetermined minimum adjustment distance Δx from the normal position. Furthermore, as shown in FIG. 1b, the piston 10 fluid-tightly seals the first partial volume 12a from the second partial volume 12b such that a first pressure p1 present in the first partial volume 12a can differ from a second pressure p2 prevailing in the second partial volume 12b from the time of adjustment of the piston 10 by at least a predetermined minimum adjustment distance Δx from the normal position.

[0027] Thus, while the piston 10 is in its normal position, a driver of a vehicle equipped with the brake system of FIGS. 1a and 1b can apply the brakes to the (at least one) wheel brake cylinder 18 via the bypass line 20 by operating a brake operating element arranged on the brake cylinder 16, thereby causing the driver's braking force to increase the brake pressure in the (at least one) wheel brake cylinder 18, thereby slowing or stopping the vehicle. Therefore, when the piston 10 is in its normal position, a mechanical fallback level exists in the brake system / hydraulic brake system formed with the brake system. Additionally, in the brake system of FIGS. 1a and 1b, the (at least one) wheel brake cylinder 18 is hydraulically disconnected from the brake cylinder 16 by adjusting the piston 10 by at least a minimum adjustment distance Δx from the normal position, so that the brake pressure in the (at least one) wheel brake cylinder 18 can be adjusted by further adjusting the piston 10. Therefore, after adjusting the piston 10 by at least a predetermined minimum adjustment distance Δx, the ABS function can be performed. Therefore, a hydraulic braking system equipped with the braking device described herein may also be referred to as an ABS system.

[0028] The advantageous placement and configuration of the check valve 22 additionally eliminates the need to configure the piston 10 to seal or separate the bypass line 20 by mechanical contact of the piston 10 with at least one interior wall of the reservoir volume 12, as required by the prior art. Therefore, the prior art requirement of configuring the piston 10 such that the first area of ​​the piston 10 dividing the first partial volume 12a is greater than the second area of ​​the piston 10 dividing the second partial volume 12b is eliminated. Furthermore, the prior art requirement still requires that the first pressure p1 in the first partial volume 12a be greater than the second pressure p2 in the second partial volume 12b in order for the piston 10 to fluid-tightly seal the first partial volume 12a from the second partial volume 12b by expanding its diameter, as still required by the prior art. The elimination of the prior art requirement contributes to the ability to adjust the piston 10 of the brake device described herein by at least the minimum adjustment distance Δx from its normal position with an equally small force. In this way, the energy consumption incurred for adjusting the piston 10 by at least the minimum adjustment distance Δx from the normal position is reduced compared to the prior art. However, despite the advantages described herein, in the brake system of Figures 1a and 1b, the mechanical fallback level and the hydraulic decoupling of the (at least one) wheel brake cylinder 18 from the brake cylinder 16 when the piston 10 is in the normal position is achieved by the piston 10 being adjusted by at least the minimum adjustment distance Δx from the normal position.

[0029] As soon as the motor 14 is stopped, the piston 10 can be returned to its normal position again by the (optional) return spring 23. From the moment the piston 10 is in its normal position, the brake can then be applied again to the (at least one) wheel brake cylinder 18 via the brake cylinder 16. Furthermore, from the moment the piston 10 is in its normal position, it is ensured that the check valve 22 is again brought into its open state.

[0030] Advantageously, in the embodiment of FIGS. 1a and 1b, the piston 10 is formed / molded such that the piston 10 has a cylindrical base body 10a and a protruding ring portion 10b at the base body 10a. The ring portion 10b is fixedly connected to the base body 10a. In particular, the base body 10a and the ring portion 10b are molded together as a compact part, for example, by being cast / injection molded together. The ring portion 10b fluid-tightly seals the first partial volume 12a of the storage volume 12 located on a first side of the ring portion 10b from the second partial volume 12b of the storage volume 12 located on a second side of the ring portion 10b. The cylindrical base body 10a extends from a first recess 24a located on the first side of the ring portion 10b through the storage volume 12 to a second recess 24b located on the second side of the ring portion 10b. The geometry of the piston 10 described herein also contributes to an additional reduction in the force required to adjust the piston 10 and the associated energy consumption incurred when adjusting the piston 10.

[0031] In the embodiment of FIGS. 1a and 1b, the piston 10 is provided with a pin 26, which is adjustable together with the piston 10. The pin 26 can also be manufactured together with the piston 10 as a compact part, for example by co-casting / co-injection molding. The pin 26 holds the check valve 22 in an open state, at least when the piston 10 is in its normal position. Furthermore, the pin 26 is adjusted together with the piston 10, which is adjusted by at least a minimum adjustment distance Δx from its normal position, so that the check valve 22 is switched to a closed state by the pin 26, which is adjusted together with the piston 10. In particular, the check valve 22 can be configured such that the check valve 22 (automatically) switches to a closed state when the pin 26, which is adjusted together with the piston 10, moves away from the check valve 22 by at least the minimum adjustment distance Δx. This can be achieved, for example, by forming the check valve 22 with a spring device, the force of which acts to move the check valve 22 to a closed state as soon as the pin 26 no longer opposes the force of the spring device of the check valve 22. However, the configuration of the piston 10 with the pin 26 attached thereto described herein should be considered as exemplary only.

[0032] 2a to 2d show schematic diagrams of a second embodiment of the braking device.

[0033] The embodiments described herein are shown in Figures 2a and 2b as cross sections along line AA' in Figures 2c and 2d, respectively, with viewers of Figures 2a and 2b looking at different sides along line AA'. The applicability of the brake devices of Figures 2a-2d is not limited to specific brake system types and specific vehicle / automobile types.

[0034] 2a and 2b each show the piston 10 in its normal position. The piston 10 is held in its normal position by, among other things, the force of a return spring 23, which may be formed, for example, as a torsion spring. Additionally, if a first pressure p1 present in the first partial volume 12a is greater than a second pressure p2 present in the second partial volume 12b, the resulting pressure can also push the piston 10 toward its normal position. Operation of the motor 14 results in rotation of the nut 27, which is converted by the spindle 28 into a linear movement of the piston 10 from its normal position. In particular, the spindle 28 is pressed into the piston 10. By way of example only, the spindle 28 in the illustrated embodiment is formed as a non-self-locking, steeply threaded spindle, which, when the motor 14 is switched off, automatically returns the adjusted piston 10 to its normal position based on the force of the return spring 23 and, if necessary, pressure. Therefore, there is no need for active motor assistance from the motor 14 to return the piston 10 to its normal position.

[0035] As can be seen from FIGS. 2a to 2d, in this embodiment, the bypass line 20 and the check valve 22 are formed within the piston 10. In this case, the term "integration of the bypass line 20 and the check valve 22 into the piston 10" can also be used. The check valve 22 formed within the piston 10 is held open by a plunger 32 fixedly arranged in the brake device and protruding into an opening 30 in the piston 10 when the piston 10 is in its normal position. The plunger 32 is fixedly arranged / attached to the brake device such that an adjustment movement of the piston 10, as adjusted by the motor 14, results in relative movement of the plunger 32 within the opening 30. This relative movement of the plunger 32 can be referred to as "pulling the plunger 32 into" or "pulling the plunger 32 out of" the opening 30. In this way, the check valve 22 is switched to a closed state as soon as the piston is adjusted relative to the plunger 32 by at least a minimum adjustment distance Δx from its normal position.

[0036] The opening 30 includes an outer portion 30a and an inner portion 30b, which are formed such that the maximum area of ​​a cross section of the outer portion 30a oriented perpendicular to the longitudinal direction of the opening 30 is smaller than the maximum area of ​​a cross section of the inner portion 30b oriented perpendicular to the longitudinal direction of the opening 30. A narrowing 34, such as a radial step 34, is formed in the opening between the outer portion 30a and the inner portion 30b.

[0037] Advantageously, the check valve 22 formed in the piston 10 comprises a valve body 22a and a spring device 22b, which are arranged in the opening 30. The valve body 22a may be spherically shaped. A spherical spring seat 33 can be attached to the opening 30 of the piston 10 to support the spring device 22b on the side of the spring device facing away from the valve body 22a.

[0038] 2a and 2b, when the piston 10 is in its normal position, the valve body 22a is moved away from the constriction 34 formed in the opening 30 by the plunger 32 protruding into the opening 30 of the piston 10 against the force F of the spring device 22b. Therefore, when the piston 10 is in its normal position, there is no mechanical contact between the valve body 22a and the constriction 34. In contrast, from the moment of adjustment of the piston 10 by at least the minimum adjustment distance Δx from the normal position (and the moment of “withdrawal of the plunger 32 from the opening 30” by at least the minimum adjustment distance Δx), the force F of the spring device 22b pushes the valve body 22a toward the constriction 34 so that the mechanical contact between the valve body 22a and the constriction 34 fluid-tightly seals the outer side 30a of the opening 30 from the inner side 30b of the opening 30.

[0039] The bypass line 20 formed in the piston 10 includes a first radial contact hole 36a extending from a first partial volume 12a of the storage volume 12 through the piston 10 to an inner portion 30b of the opening 30, and a second radial contact hole 36b extending from an outer portion 30a of the opening 30b through the piston 10 to a second partial volume 12b of the storage volume 12.

[0040] When the piston 10 is in its normal position, mechanical contact between the valve body 22a and the constriction 34 is prevented by the plunger 32, so that the transfer of brake fluid between the first partial volume 12a of the storage volume 12 and the second partial volume 12b of the storage volume 12 can be achieved by the first radial contact hole 36a, the constriction 34 of the opening 30, and the second radial contact hole 36b. Therefore, when the piston 10 is in its normal position, the check valve 22 is in its open state. However, from the moment of adjustment of the piston 10 by at least the minimum adjustment distance Δx from the normal position (and “withdrawal of the plunger 32 from the opening 30” by at least the minimum adjustment distance Δx), the constriction 34 of the opening 30 is sealed by the mechanical contact of the valve body 22a and the constriction 34, so that such transfer of brake fluid between the first partial volume 12a and the second partial volume 12b is prevented and the check valve 22 is moved to its closed state. As soon as the check valve 22 is closed, a further stroke of the piston 10 can suck a volume (Volumen) from the (at least one) wheel brake cylinder 18 into the storage volume 12, thereby resulting in a modulation of the brake pressure in the (at least one) wheel brake cylinder 18. During the modulation, the check valve 22 remains in the closed state, since the mechanical contact between the valve body 22a and the restriction 34 is maintained. Only when the piston 10 is returned to its normal position does the "retraction of the plunger 32 into the opening 30" eliminate the mechanical contact between the valve body 22a and the restriction 34, and the check valve 22 is moved into the open state.

[0041] As can be further seen in Figures 2a-2d, the piston 10 may be guided by at least one guide pin 38. The at least one guide pin 38 may be attached to the piston 10 and may project into at least one guide opening external to the piston. Alternatively, the at least one guide pin 38 may be attached to the exterior of the piston 10 and may project into at least one guide opening formed in the piston 10. In the embodiment of Figures 2a-2d, by way of example only, the piston 10 is guided by three guide pins 38.

[0042] For further features and characteristics of the braking device of Figures 2a-2d and their advantages, please refer to the description of Figures 1a and 1b.

[0043] FIG. 3 shows a flow chart illustrating one embodiment of a method for operating a vehicle hydraulic braking system.

[0044] The method described below can be implemented in (almost) any hydraulic brake system of a vehicle that is equipped with an adjustable piston within the reservoir volume of the hydraulic brake system that divides the reservoir volume into a first partial volume and a second partial volume.

[0045] In method step S1, a bypass line, through which brake fluid can be transferred from a first partial volume and / or a brake cylinder associated with the first partial volume to a second partial volume and / or a wheel brake cylinder associated with the second partial volume when at least the piston is in its normal position, is switched open and / or held open, and for this purpose a check valve arranged in the bypass line and open when at least the piston is in its normal position is switched open and / or held open by adjusting and / or holding the piston in its normal position.

[0046] In response to this, in method step S2, the transfer of brake fluid via / through the bypass line is interrupted by adjusting the piston by at least a predetermined minimum adjustment distance from its normal position, in that the check valve is switched to its closed state by the piston being adjusted by at least the minimum adjustment distance from its normal position, as a result of the adjustment of the piston by at least the predetermined minimum adjustment distance from its normal position brought about by the operation of the motor.

[0047] Method steps S1 and S2 can be performed alternately. [Explanation of symbols]

[0048] 10 pistons 10a Base 10b Ring section 12 Brake system storage volume 12a First partial volume 12b Second partial volume 12c port 14 Motor 15a First Line Component 15b Second Line Component 16 Brake cylinder 18 Wheel brake cylinder 20 Bypass Line 22 Check valve 22a Valve body 22b Spring device 23 Return spring 24a notch 26-pin 27 Nut 28 Spindle 30 aperture 30a outer part 30b Inside part 32 Plunger 34 Constriction, radial step 38 Guide pin p1 First pressure p2 Second pressure Δx Minimum adjustment distance

Claims

1. a piston (10) adjustable in a storage volume (12) by actuation of a motor (14) of the brake system, the piston dividing the storage volume (12) into a first partial volume (12a) and a second partial volume (12b), a brake cylinder (16) native to the system or external to the system being coupled or connectable to the first partial volume (12a) so as to transfer brake fluid between the brake cylinder (16) and the first partial volume (12a), and a wheel brake cylinder (18) native to the system or external to the system being coupled or connectable to the second partial volume (12b) so as to transfer brake fluid between the second partial volume (12b) and the wheel brake cylinder (18), a bypass line (20) for transferring brake fluid from the first partial volume (12a) and / or the brake cylinder (16) connected to the first partial volume through the bypass line (20) to the second partial volume (12b) and / or the wheel brake cylinder (18) connected to the second partial volume, when at least the piston (10) is in a normal position, while the transfer of brake fluid through the bypass line (20) is prevented by the piston (10) being adjusted by at least a predetermined minimum adjustment distance (Δx) from the normal position; 1. A brake device for a hydraulic brake system of a vehicle, comprising: a check valve (22) arranged in the bypass line (20), the check valve (22) being in an open state at least when the piston (10) is in the normal position and switchable by the piston (10) so as to be switched to a closed state by the piston (10) being adjusted by at least a minimum adjustment distance (Δx) from the normal position; 1. A braking device comprising: a piston (10) having a cylindrical base (10a) and a ring portion (10b) protruding from the base (10a), the ring portion (10b) of the piston (10) fluid-tightly sealing a first partial volume (12a) of the storage volume (12) located on a first side of the ring portion (10b) from a second partial volume (12b) of the storage volume (12) located on a second side of the ring portion (10b), and the cylindrical base (10a) extending from a first notch (24a) located on the first side of the ring portion (10b) through the storage volume (12) to a second notch (24b) located on the second side of the ring portion (10b).

2. 2. The braking device according to claim 1, wherein the piston (10) is guided by at least one guide pin (38).

3. 3. The brake device according to claim 1, wherein the bypass line (20) and the check valve (22) are formed in the piston (10).

4. 4. The braking device according to claim 3, wherein the check valve (22) formed in the piston (10) is held open by a plunger (32) protruding into an opening (30) of the piston (10) fixedly arranged in the braking device when the piston (10) is in the normal position, while the piston (10) adjusted by at least the minimum adjustment distance (Δx) from the normal position is adjusted relative to the plunger (32) so that the check valve (22) is switched to a closed state.

5. The check valve (22) formed in the piston (10) includes a valve body (22a) and a spring device (22b), and the valve body (22a) is held away from a narrowed portion (34) formed in the opening (30) by the plunger (32) protruding into the opening (30) of the piston (10) against a force (F) of the spring device (22b) when the piston (10) is in the normal position, while the valve body (22a) is held away from a narrowed portion (34) formed in the opening (30) against a force (F) of the spring device (22b) when the piston (10) is in the normal position.

5. The braking device according to claim 4, wherein the force (F) of the spring device (22b) urges the valve body (22a) towards the constriction (34) in such a way that, from the time of adjustment by at least the minimum adjustment distance (Δx), the mechanical contact between the valve body (22a) and the constriction (34) provides a fluid-tight seal between an outer side (30a) of the opening (30) located on a first side of the constriction (34) and an inner side (30b) of the opening (30) located on a second side of the constriction (34).

6. 6. The brake device of claim 5, wherein the bypass line formed in the piston includes a first radial contact hole extending through the piston from the first partial volume of the storage volume to the inner portion of the opening, and a second radial contact hole extending through the piston from the outer portion of the opening to the second partial volume of the storage volume.

7. 3. The braking device according to claim 1, wherein a pin (26) is attached to the piston (10), the pin being adjustable together with the piston (10), and the pin holds the check valve (22) in an open state at least when the piston (10) is in the normal position, while the check valve (22) is switched to a closed state by the pin (26) being adjusted together with the piston (10) adjusted by at least the minimum adjustment distance (Δx) from the normal position.

8. A hydraulic brake system for a vehicle, comprising: The brake device according to claim 1 or 2; the brake cylinder (16) coupled to the first partial volume (12a) of the reservoir volume (12) of the brake device; the wheel brake cylinder (18) coupled to the second partial volume (12b) of the reservoir volume (12).

9. 1. A method of operating a hydraulic braking system of a vehicle comprising an adjustable piston (10) in a reservoir volume (12) of the hydraulic braking system, dividing said reservoir volume (12) into a first partial volume (12a) and a second partial volume (12b), the method comprising the steps of:

1. A method comprising: preventing transfer of brake fluid from the first partial volume (12 a) and / or a brake cylinder (16) connected to the first partial volume (12 a) to the second partial volume (12 b) and / or a wheel brake cylinder (18) connected to the second partial volume (12 b) via a bypass line (20) capable of transferring brake fluid at least when the piston (10) is in the normal position by operating a motor (14) to adjust the piston (10) from a normal position by at least a predetermined minimum adjustment distance (Δx), a check valve (22) disposed in the bypass line (20) and in an open state when at least the piston (10) is in the normal position is switched to a closed state by the piston (10) being adjusted by at least the minimum adjustment distance (Δx) from the normal position (S2); 1. The method of claim 1, wherein the piston (10) has a cylindrical base (10a) and a ring portion (10b) protruding from the base (10a), the ring portion (10b) of the piston (10) fluid-tightly seals the first partial volume (12a) of the storage volume (12) located on a first side of the ring portion (10b) from the second partial volume (12b) of the storage volume (12) located on a second side of the ring portion (10b), and the cylindrical base (10a) extends from a first notch (24a) located on the first side of the ring portion (10b) through the storage volume (12) to a second notch (24b) located on the second side of the ring portion (10b).

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