VALVE ARRANGEMENT

Abstract

A valve arrangement is inserted between a master brake cylinder and a reservoir in a housing of an electrohydraulic motor vehicle brake system which can be activated both by a vehicle driver and independently of the vehicle driver. The valve arrangement can be acted on by a volume flow which can be conveyed by a linear actuator in the direction of a pedal travel simulator, the working chamber of the pedal travel simulator being connected to the master brake cylinder, wherein, for the purpose of simplified construction and actuation, the valve arrangement has a hydraulically actuable non-return valve and a fixed diaphragm arranged parallel to the non-return valve. The non-return valve is arranged together with the fixed diaphragm in a valve carrier which is fastened to a closure plug which closes the housing of the motor vehicle brake system.

Description

TECHNICAL FIELD

The invention relates to a valve arrangement for an electrohydraulic motor vehicle brake system.

BACKGROUND

An electrohydraulic motor vehicle brake system with a manually actuable master brake cylinder, a pressure medium reservoir, an electrically actuable inlet and outlet valve for each wheel brake for setting wheel-specific brake pressures, an electrically controllable linear actuator for pressurizing the wheel brakes in the “brake-by-wire” operating mode, a pedal travel simulator which can be hydraulically acted on by the master brake cylinder and gives the vehicle driver a defined brake pedal feel in the “brake-by-wire” operating mode, and an electromagnetically actuable valve arrangement is provided between the master brake cylinder and the reservoir.

Therefore, a valve arrangement of the specified type using means which are as simple, inexpensive and functionally reliable as possible, without the need for electromagnetic actuation is useful.

BRIEF SUMMARY

A valve arrangement is inserted between a master brake cylinder and a reservoir in a housing of an electrohydraulic motor vehicle brake system which can be activated both by a vehicle driver and independently of the vehicle driver, wherein the valve arrangement can be acted on by a volume flow which can be conveyed by a linear actuator in the direction of a pedal travel simulator, the working chamber of the pedal travel simulator are connected to the master brake cylinder. The valve arrangement has a hydraulically actuable non-return valve and a fixed diaphragm arranged parallel to the non-return valve, wherein the non-return valve is arranged together with the fixed diaphragm in a valve carrier which is fastened to a closure plug which closes the housing of the motor vehicle brake system.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features will become apparent below from the description of several exemplary embodiments with reference to drawings, in which:

FIG. 1 shows a schematic representation of the hydraulic circuit structure for an electrohydraulic brake system which is provided with a newly designed valve arrangement; and

FIG. 2 shows, in longitudinal section, a schematic detail of the electrohydraulic brake system for illustrating the structural design of the valve arrangement.

DETAILED DESCRIPTION

FIG. 1 shows a basic representation of the valve arrangement V1 which is inserted between a master brake cylinder 8 and a reservoir 9 of an electrohydraulic motor vehicle brake system.

The motor vehicle brake system can be activated independently of the vehicle driver owing to the use of a pedal travel simulator 13 connected to the master brake cylinder 8 and the connection of a linear actuator 14 between the reservoir 9 and the wheel brakes 17, wherein, for the purpose of diagnosing the brake system, the valve arrangement V1 can be acted on by a volume flow which can be conveyed by the linear actuator 14 in the direction of the pedal travel simulator 13, the working chamber of the pedal travel simulator being connected to the master brake cylinder 8 via an electromagnetically actuable simulator valve SIV.

The desired varied operating modes of the brake system can be implemented by means of further solenoid valves MCV, CSV, PFV, which are arranged upstream of the wheel pressure control valves WV of the wheel brakes 17.

The so-called fallback level of the brake system can be tested by means of the valve arrangement V1, for which purpose a defined volume flow is conveyed by the linear actuator 14 into the working chamber of the pedal travel simulator 13. This takes place under the condition that the return flow from the master brake cylinder 8 in the direction of the reservoir 9 is significantly reduced at least by the build-up of a back pressure, which is why the valve arrangement V1 has a fixed diaphragm 2 arranged parallel to a non-return valve 1.

A dynamic pressure of defined magnitude can therefore be generated in the direction of the reservoir 9 by means of the fixed diaphragm 2, this ensuring that the pedal travel simulator 13 is filled with the volume flow generated by the linear actuator 14, while, on the other hand, unrestricted throughflow is established exclusively from the reservoir 9 to the master brake cylinder 8 by the non-return valve 1 as required for supplying pressure as quickly as possible. In order to ensure the fixed diaphragm function, however, the throughflow is in principle blocked by means of the non-return valve 1 in the opposite direction.

As can be seen from FIG. 2, the non-return valve 1 is arranged together with the fixed diaphragm 2 in a valve carrier 3 which is fastened with a compact design to a closure plug 5 which closes the housing 4 of the motor vehicle brake system.

This ensures that, after the valve carrier 3 has been pressed onto the closure plug 5, an independently handleable assembly which can be pre-tested with regard to the function of the fixed diaphragm 2 and the non-return valve 1 and can be fixed into a blind hole 6 in the housing 4 with minimal effort is produced.

As can be seen from FIG. 2, a first channel A which is arranged in the housing 4 and is connected to the master brake cylinder 8 shown in FIG. 1 opens into the bottom 7 of the blind hole 6. Furthermore, a second channel B which is arranged in the housing 4 and is connected to the reservoir 9 known from FIG. 1 opens into the lateral surface of the blind hole 6.

The design results in a compressed footprint in the vertical direction since the closure plug 5 has a recess 10 in the direction of the valve carrier 3, into which recess a sleeve projection 11 of the valve carrier 3, which sleeve projection comprises the fixed diaphragm 2, extends in sections, wherein a cavity 12 is provided between the valve carrier 3 and the closure plug 5 to establish a pressure medium connection between the first and the second channel A, B, so that, depending on the direction of throughflow, the two channels A, B can be connected to one another in a particularly simple manner via the fixed diaphragm 2 and/or the non-return valve 1.

When viewed together with FIG. 1, a dynamic pressure of defined magnitude can therefore be generated in the direction of the reservoir 9 using the illustrated fixed diaphragm 2, this ensuring that the pedal simulator 13 is filled with the volume flow generated by the linear actuator 14, while unrestricted throughflow from the reservoir 9 to the master brake cylinder 8 is possible by way of the non-return valve 1, but the throughflow is interrupted by the non-return valve 1 in the opposite direction.

For the purpose of structurally optimal positioning of all the components, the sleeve projection 11 comprising the fixed diaphragm 2 is arranged on the axis of symmetry of the valve carrier 3 analogously to the recess 10, so that the non-return valve 1 can be arranged next to the sleeve projection 11 in a vertical passage hole 15 in the base 16 of the valve carrier 3 in an expedient manner in terms of flow.

In order to avoid contamination of the fixed diaphragm 2 and the non-return valve 1, a respective filter element 16 is arranged on the bottom and on the lateral surface of the valve carrier 3. The filter element 16 arranged on the bottom of the valve carrier 3 covers the non-return valve 1 at an axial distance which is smaller than the dimensions of the non-return valve 1, this reliably preventing the spherical non-return valve 1 from falling out under all operating conditions.

The valve carrier 3 may be produced from a plastic by injection molding and the closure plug 5 is preferably produced from an aluminum alloy by cold extrusion, with the feature that the annular filter fabric of the filter element 16 can be inserted and overmolded in one operation during the production of the valve carrier 3.

The required sealing of the valve carrier 3 within the blind hole 6 is ensured by a radial press connection at the end region of the valve carrier 3. Similarly, the closure plug 5, in the region of its collar 18, is fixed in the blind hole 6 in a pressure medium-tight manner by externally calking the housing material.

Claims

1-11. (canceled)

12. A valve system for an electrohydraulic motor vehicle brake system comprising: a valve arrangement inserted between a master brake cylinder and a reservoir in a housing of the brake system, wherein the valve can be activated by a vehicle driver and independently of the vehicle driver;a linear actuator to convey a volume flow in the direction of a pedal travel simulator which actuates the valve arrangement;a working chamber of the pedal travel simulator is connected to the master brake cylinder;a hydraulically actuable non-return valve;a fixed diaphragm arranged parallel to the non-return valve, wherein the non-return valve and the fixed diaphragm are arranged in a valve carrier; andwherein the valve carrier is fastened to a closure plug which closes the housing.

13. The valve system as claimed in claim 12, wherein an independently handleable assembly is formed after the valve carrier has been fitted on the closure plug, wherein the independently handleable assembly can be pre-tested with regard to the fixed diaphragm function and the non-return valve, and wherein the independently handleable assembly is fixed into a blind hole defined by the housing.

14. The valve system as claimed in claim 13, wherein a first channel is arranged in the housing and is connected to the master brake cylinder, wherein the first channel opens into the bottom of the blind hole, and a second channel is arranged in the housing and is connected to the reservoir, wherein the second channel opens into a wall of the blind hole.

15. The valve system as claimed in claim 13, wherein the closure plug defines a recess in the direction of the valve carrier, and wherein a sleeve projection of the valve carrier extends into the recess.

16. The valve system as claimed in claim 15, wherein the sleeve projection comprises the fixed diaphragm.

17. The valve system as claimed in claim 15, wherein the sleeve projection extends in sections into the recess.

18. The valve system as claimed in claim 14, wherein a cavity is provided between the valve carrier and the closure plug to establish a pressure medium connection between the first and the second channel, such that depending on the direction of throughflow, the first and the second channel can be connected via at least one of the fixed diaphragm and the non-return valve.

19. The valve system as claimed in claim 12, wherein the fixed diaphragm generates a dynamic pressure of defined magnitude in the direction of the reservoir such that the pedal simulator is filled with the volume flow generated by the linear actuator.

20. The valve system as claimed in claim 12, wherein the non-return is positioned to allow unrestricted throughflow from the reservoir to the master brake cylinder and prevents throughflow in the opposite direction.

21. The valve system as claimed in claim 15, wherein the sleeve projection is arranged on the axis of symmetry of the valve carrier, and the non-return valve is arranged next to the sleeve projection in a vertical passage hole in the bottom of the valve carrier.

22. The valve system as claimed in claim 21, wherein a respective filter element is arranged on the bottom and on the lateral surface of the valve carrier.

23. The valve system as claimed in claim 22, wherein the filter element arranged on the bottom of the valve carrier covers the non-return valve at an axial distance which is smaller than the dimensions of the non-return valve.

24. The valve system as claimed in claim 15, wherein the valve carrier is plastic and the closure plug is an aluminum alloy.