CUBOIDAL HYDRAULIC BLOCK FOR A HYDRAULIC UNIT OF A BRAKE PRESSURE CONTROL MECHANISM OF A HYDRAULIC VEHICLE BRAKE SYSTEM

A space-saving bore arrangement in a hydraulic block of a brake pressure control mechanism of a slip-controlled hydraulic vehicle power brake system.

FIELD

The present invention relates to a hydraulic block for a hydraulic unit of a brake pressure control mechanism of a hydraulic vehicle brake system. The hydraulic block is in particular provided for a vehicle brake system comprising an external power control and/or a slip control.

BACKGROUND INFORMATION

German Patent Application No. DE 10 2016 202 113 A1 describes a narrow, cuboidal hydraulic block for a hydraulic unit of a slip-controlled hydraulic vehicle power brake system, in which a master brake cylinder bore is provided such that it extends continuously from one narrow side to an opposite narrow side and a power cylinder bore extends perpendicular to the master brake cylinder bore likewise continuously through two opposite large sides of the hydraulic block. The conventional hydraulic block also comprises a blind hole as a receptacle for a pedal travel simulator. To generate power brake pressure, a power piston can be displaced in the power cylinder bore via a ball screw drive by means of an electric motor. The electric motor is disposed coaxially to the power cylinder bore on the outside of the hydraulic block and the ball screw drive is located (likewise coaxially to the electric motor and the power cylinder bore) between the electric motor and the power piston. The electric motor and the ball screw drive form a power drive, and together with the power piston and the power cylinder bore form a power brake pressure generator for the hydraulic vehicle brake system.

SUMMARY

A hydraulic block according to the present invention is provided for a hydraulic unit of a brake pressure control mechanism of a hydraulic vehicle brake system. The hydraulic block according to an example embodiment of the present invention is in particular provided for a vehicle brake system comprising a slip control system and/or a vehicle power brake system. Brake pressure control means the generation and control of a brake pressure in the vehicle brake system, in brake circuits of the vehicle brake system and/or in hydraulic wheel brakes of the vehicle brake system that are connected to the hydraulic block. It can in particular also include a slip control. Slip control systems are anti-lock braking systems, traction control systems and/or vehicle dynamics control systems, for example, for which the abbreviations ALS, TCS and/or VDC are commonly used. Slip control systems are well-known and will not be discussed here.

The hydraulic block is used for mechanical fastening and hydraulic interconnection of hydraulic components of the vehicle brake system, the brake pressure generation and/or the brake pressure control and/or the slip control. Such hydraulic components include solenoid valves, check valves, hydraulic accumulators, damper chambers and pressure sensors, among other things. The hydraulic components are fastened in receptacles in the hydraulic block, which are typically configured as cylindrical counterbores, blind holes or through-holes, in part with diameter gradations. “Interconnected” means that the receptacles or the hydraulic components fastened in them, are connected by lines in the hydraulic block in accordance with a hydraulic circuit diagram of the vehicle brake system. The lines are typically, but not necessarily, drilled into the hydraulic block.

The hydraulic block fitted with the hydraulic components of the vehicle brake system or its slip control system forms the hydraulic unit, wherein “fitted” means that the hydraulic components are fastened in the receptacles of the hydraulic block respectively provided for them.

The hydraulic block furthermore in particular comprises terminals for the brake lines which lead to hydraulic wheel brakes of the vehicle brake system. It can also comprise terminals for the brake lines coming from a master brake cylinder, but the master brake cylinder is preferably integrated into the hydraulic block; i.e. the hydraulic block comprises a master brake cylinder bore, for example.

The present invention is directed in particular to the arrangement of the hydraulic components or their receptacles and their hydraulic connection in the hydraulic block.

For a space-saving accommodation of inlet valves and/or outlet valves of the slip control, one example embodiment of the present invention provides that its receptacles in the hydraulic block are not disposed side by side in a straight line as usual, but with an additional offset transverse to their side-by-side arrangement in the hydraulic block. For example, receptacles for inlet valves are disposed alternately on two straight lines parallel to one another in the hydraulic block instead of on one straight line. And/or a receptacle for one outlet valve is disposed transversely offset to other receptacles for outlet valves in the hydraulic block which are disposed on a straight line, for example.

The hydraulic block according to an example embodiment of the present invention preferably comprises a master brake cylinder bore for axially displaceable accommodation of one or more master brake cylinder pistons for muscle power actuation of the vehicle brake system, a power cylinder bore for generating power brake pressure, and/or a simulator cylinder bore or a receptacle for a pedal travel simulator.

A brake fluid reservoir is mounted on a side of the hydraulic block which is referred to here as the upper side of the hydraulic block and is preferably a narrow side of the hydraulic block. For this purpose, the hydraulic block comprises one or more connectors for the brake fluid reservoir in the upper side. For fastening the brake fluid reservoir to the upper side of the hydraulic block, one embodiment of the present invention provides a depression in a side of the hydraulic block adjoining said upper side that extends to the upper side. A fastening tab which protrudes from an underside of the brake fluid reservoir, for example, projects into the depression, and can be fixed in the depression, for instance with a screw, without a screw head or another part of the fastener projecting beyond a surface of the adjoining side of the hydraulic block. This does not impede insertion of an electrical plug provided on the adjoining side for contacting a control unit of the brake pressure control.

For connection to the power cylinder bore, one example embodiment of the present invention provides a line in the hydraulic block which leads from one of the connectors for the brake fluid reservoir in the upper side to the power cylinder bore. This line extends axially or axially parallel from the one connector of the brake fluid reservoir to the power cylinder bore, along which, after a bend, it extends parallel on the outside and, with a further bend, opens into the power cylinder bore. The power cylinder bore can thus be connected to the brake fluid reservoir with just a few bends. In the line, in particular in the connector and directly after the connector for the brake fluid reservoir, a check valve through which flow can pass in the direction of the power cylinder bore can be provided.

Further developments and advantageous embodiments of the present invention are disclosed herein.

Through-holes or blind holes referred to here as “lines” or “bores” or “cylinder bores” can also be produced in a manner other than drilling.

All features disclosed in the description herein and the figures can be implemented individually or in fundamentally any combination in embodiments of the present invention. Embodiments of the present invention which do not comprise all but only one or more features of an embodiment of the present invention are possible in principle. Possible are in particular also embodiments of the present invention in which the receptacles for the inlet valves and/or the receptacles for the outlet valves are disposed otherwise than as stated herein.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG.1shows a hydraulic multi-circuit, specifically dual circuit vehicle power brake system1comprising two brake circuits I, II and four hydraulic wheel brakes2, of which two are respectively connected to a brake circuit I, II. The vehicle brake system1comprises a dual circuit master brake cylinder4that can be actuated with muscle power using a foot brake pedal3and a power brake pressure generator5. The two brake circuits I, II are hydraulically connected in parallel to the master brake cylinder4and to the power brake pressure generator5, wherein each brake circuit I, II is connected to the master brake cylinder4via a respective separator valve6and to the power brake pressure generator5via a respective power valve7.

In one of the two brake circuits I, i.e., to one chamber of the dual circuit master brake cylinder4, a piston cylinder unit9comprising a spring-loaded piston10is connected via a simulator valve8as a pedal travel simulator11.

The master brake cylinder4comprises an unpressurized brake fluid reservoir12, to which the two chambers or brake circuits I, II of the master brake cylinder4are connected. One of the two chambers of the master brake cylinder4is connected to the brake fluid reservoir12via a test valve13and hydraulically in parallel via a check valve through which flow can pass in the direction of the master brake cylinder4, and the other chamber of the master brake cylinder4is connected directly to the brake fluid reservoir.

The power brake pressure generator5comprises a piston cylinder unit14, the piston15of which can be displaced in a cylinder18of the piston cylinder unit14via a screw drive17by means of an electric motor16to generate power brake pressure. The two brake circuits I, II of the vehicle brake system1are connected to the cylinder18of the power brake pressure generator5via the two power valves7.

The cylinder18of the piston cylinder unit14of the power brake pressure generator5is connected to the brake fluid reservoir12via a check valve19through which flow can pass in the direction of the cylinder18and is connected to the brake fluid reservoir12directly by a line20without the interposition of a valve. At the beginning of its displacement, the piston10of the power brake pressure generator5passes over a mouth of this line20so that, when the power brake pressure generator5is actuated, the piston cylinder unit14of the power brake pressure generator5is hydraulically separated from the brake fluid reservoir12.

Each wheel brake2is connected to one of the two brake circuits I, II via an inlet valve21and to the unpressurized brake fluid reservoir12via an outlet valve22.

The power brake pressure generator5, the inlet valves21and the outlet valves22form brake pressure control valve assemblies that are capable of carrying out wheel-specific slip control, such as antilock control, traction slip control, and vehicle dynamics control. These slip controls are typically abbreviated as ALS, TCS, and VDC. Such slip controls are well-known and will not be discussed here.

In the illustrated and described embodiment of the present invention, the separator valves6, the power valves7, the simulator valve8, the test valve13, the inlet valves21and the outlet valves22are 2/2-way solenoid valves, wherein the separator valves6, the test valve13, and the inlet valves21are open in their currentless home positions, and the power valves7, the simulator valve8and the outlet valves22are closed in their currentless home positions.

Pressure sensors23,24are connected to one of the two chambers of the master brake cylinder4and to the cylinder18of the power brake pressure generator5. A displacement or position sensor45for measuring a piston or pedal displacement or a piston or pedal position of the master brake cylinder piston53or the foot brake pedal3is disposed on a pedal rod connecting the foot brake pedal3to a master brake cylinder piston53.

Service braking takes place as power braking with the power brake pressure generator5. For this purpose, the power valves6are opened and a brake pressure is generated with the power brake pressure generator5, which acts upon the wheel brakes2via the open inlet valves21thus actuating said wheel brakes.

During service braking, the master brake cylinder4is hydraulically separated from the brake circuits I, II by closing the separator valves6. It serves as a setpoint generator for the brake pressure to be generated with the power brake pressure generator5. The simulator valve8is opened during service braking, so that the master brake cylinder4can displace brake fluid in the pedal travel simulator11and piston and pedal displacement on the master brake cylinder4are possible.

In the event of a malfunction or failure of the power brake pressure generator5, auxiliary braking by muscle power actuation of the master brake cylinder4is possible, wherein the separator valves6remain open and the power valves7remain closed.

The hydraulic components of the vehicle brake system1are disposed in and on a hydraulic block25which is shown inFIGS.2and3. The hydraulic block25is drawn transparently so that its bore arrangement can be seen.FIG.2shows a valve side26andFIG.3shows an opposite motor side27of the hydraulic block25. In this embodiment example, the hydraulic block25is a flat, cuboid metal block used for mechanical fastening and hydraulic interconnection of the hydraulic components of the vehicle brake system1. The hydraulic block25fitted with the hydraulic components forms a hydraulic unit32of the vehicle brake system1, which is shown inFIG.4in a perspective view looking onto the motor side27. “Flat” means that hydraulic block25is about 3 to 4 times as wide or long as it is thick. Two opposite large sides of the hydraulic block25in this embodiment example are nearly square and form the valve side26and the motor side27.

In the hydraulic block25, a master brake cylinder bore4′ which forms the master brake cylinder4, a power cylinder bore which forms the cylinder18of the power brake pressure generator5, a cylinder bore28which forms the cylinder of the piston cylinder unit9of the pedal travel simulator11, receptacles for the solenoid valves6,7,8,13,21,22, a receptacle for the check valve19, receptacles for the pressure sensors23,24, connectors29for the brake fluid reservoir12and connectors30for the hydraulic wheel brakes2are attached to the hydraulic block25by means of brake lines. The receptacles for the solenoid valves, the check valve and the pressure sensors are provided inFIGS.2and3with the same reference numbers as the respective hydraulic components inFIG.1with the addition of a “′”.

The receptacles are cylindrical, partly diameter-stepped counterbores or blind holes in the hydraulic block25. The hydraulic components are placed into the receptacles and are caulked all around to be made pressure-tight. Hydraulic sections of the solenoid valves that form the actual valves are located in the receptacles, and armatures and solenoid coils housed in a valve dome, project from the valve side26of the hydraulic block1. The connectors29for the brake fluid reservoir12are also blind holes into which connecting nipples that project from a base of the brake fluid reservoir12are inserted and sealed with sealing rings. The connection bores30for the wheel brakes2are likewise blind holes in which the brake lines leading to the wheel brakes2are fastened in a pressure-tight manner with not-depicted press-in nipples using so-called self-clinch technology. It is also possible to connect the brake lines with screw nipples, for example. Lines configured in the hydraulic block1as bores connect the cylinder bores, the receptacles for the hydraulic components and the connectors29,30for the brake fluid reservoir12and the wheel brakes2to one another in accordance with the hydraulic circuit diagram inFIG.1.

“Drilled” or “bore arrangement” refers to the cylinder bores, receptacles for the solenoid valves and connection bores provided in the hydraulic block1, as well as the bores forming lines that connect them in accordance with the hydraulic circuit diagram. The hydraulic block25is drilled in a Cartesian configuration, i.e. the bores, receptacles, connectors, lines, etc. are provided in the hydraulic block25parallel and perpendicular to one another and to the sides and edges of the hydraulic block25. This does not exclude individual, obliquely extending lines and bores. “Fitted” means that the hydraulic components are disposed in their receptacles.

The brake fluid reservoir12is placed on an upper side31of the hydraulic block25adjoining the valve side26and the motor side27such that the connecting nipples on the base of the brake fluid reservoir12are inserted in the connectors29in the upper side31of the hydraulic block25. The brake fluid reservoir12comprises three chambers, two of which are connected to the two chambers of the master brake cylinder4and one of which is connected to the cylinder18of the piston cylinder unit14of the power brake pressure generator5via the check valve19and the line20. The connectors29are disposed in a longitudinal direction of the upper side31of the hydraulic block25one behind the other and in somewhat of a V-shape; i.e. a middle one of the three connectors29is disposed offset to the two other connectors29in the upper side31of the hydraulic block25transverse to the upper side31.

The brake fluid reservoir12comprises two eye shackles33at which it is fastened on the upper side31of the hydraulic block with shoulder screws34and an eye shackle35which projects for the base and at which it is fastened on the hydraulic block with a stud bolt36(FIG.4). The stud bolt36enables length compensation in the event of thermal expansion of the hydraulic block25. The eye shackle35is located in a depression37in a side38of the hydraulic block25adjoining the upper side31, the valve side26and the motor side27, which extends to the upper side31. A screw head of the stud bolt36is countersunk in the depression37as well, so that nothing projects on the side38.

On the valve side26of the hydraulic block25, a control unit cover39with an electronic control unit for the brake pressure control mechanism is disposed, which comprises a multipolar electric coupling40located on the side38of the hydraulic block25. Due to the countersunk arrangement of the eye shackle of the brake fluid reservoir12together the stud bolt36in the depression37, the eye shackle35and the stud bolt36do not impede insertion and removal of a not-depicted plug in the coupling40.

The master brake cylinder bore4′ forming the master brake cylinder4is provided in the hydraulic block25with a spacing from the upper side31and parallel to the upper side31, the valve side26and the motor side27above a center of the hydraulic block25.

The cylinder18of the piston cylinder unit14of the power brake pressure generator5is mounted in the hydraulic block25in the motor side27perpendicular to the valve side26and the motor side27. An elevation41into which the cylinder18of the power brake pressure generator5extends projects from the hydraulic block25from the valve side26. The cylinder18of the piston cylinder unit14of the power brake pressure generator5is mounted in the hydraulic block25perpendicular to the master brake cylinder bore4′ and directly adjacent to the master brake cylinder bore4′. “Directly adjacent” means that there is no hollow space in the hydraulic block25between the cylinder18of the piston cylinder unit14of the power brake pressure generator5and the master brake cylinder bore4′.

The cylinder18of the piston cylinder unit14of the power brake pressure generator5is connected as stated to the center connector29of the brake fluid reservoir12via the check valve19. For this purpose, the line20leads coaxially from a base of the connector29to close to a perimeter of the cylinder18, from where, with a right angle bend, the line20leads axially parallel to the cylinder18along the outside of the cylinder18in the elevation41and opens into the cylinder18with a recess51. The recess51is a type of peripheral groove in the cylinder18of the power brake pressure generator5that extends only over a part of a perimeter of the cylinder18. It can also be implemented such that it extends all the way around. The recess51can generally also be understood as a bend through which the line20opens into the cylinder18. At the base of the connector29, the check valve19is disposed in a diameter widening of the line20that forms a receptacle19′ for the check valve19.

The cylinder bore28of the pedal travel simulator11is provided vertically in the valve side26of the hydraulic block25directly adjacent to the cylinder18of the power brake pressure generator5between the cylinder18of the piston cylinder unit14of the power brake pressure generator5and a corner of the hydraulic block25. “Directly adjacent” means that there is no hollow space in the hydraulic block25between the cylinder bore28of the pedal travel simulator11and the cylinder18of the power brake pressure generator5.

Parallel to and close to the master brake cylinder bore4′, the hydraulic block25comprises a significantly thinner bore as a position indicator bore43for a master brake cylinder piston (primary or rod piston)53. The position indicator bore43opens on the same side, in this embodiment example on the fastening side46of the hydraulic block25, as the master brake cylinder bore4′. A rod-shaped indicator holder mounted outside the hydraulic block25on a piston rod42connected to the master brake cylinder piston53(not shown) plunges into the position indicator bore43, so that the indicator holder moves with the master brake cylinder piston53. A permanent magnet, for instance, is fastened to the indicator holder as a signal generator located in the position indicator bore43.

A blind hole is provided in the hydraulic block25perpendicular to the position indicator bore43as a receptacle44for the displacement or position sensor45. The receptacle44is located above, i.e. on a side of the position indicator bore43facing the upper side31of the hydraulic block25, and close to the mouth of the position indicator bore43or close to the mouth of the master brake cylinder bore4′ or close to the fastening side46of the hydraulic block25.

The master brake cylinder4and the position indicator bore43are open on a fastening side46of the hydraulic block25which adjoins the valve side26, the motor side27and the upper side31and faces the side38comprising the depression37. The hydraulic block25is fastened with the fastening side46to a not-depicted bulkhead of a motor vehicle such that the upper side31with the brake fluid reservoir12is at the top.

The electric motor16is disposed on the outside of the motor side27of the hydraulic block25coaxially with the cylinder18of the piston cylinder unit14of the power brake pressure generator5. A not-depicted planetary gear as a reduction gear and a ball screw drive for converting a rotational driving of the electric motor16into a translational movement for displacing the piston15of the piston cylinder unit14of the power brake pressure generator5are disposed coaxially with the electric motor16and the cylinder18in a motor housing of the electric motor16and in the cylinder18of the power brake pressure generator5.

Three through-holes which extend from the valve side26to the motor side27are provided in the hydraulic block25between the cylinder18of the piston cylinder unit14of the power brake pressure generator5and an underside47of the hydraulic block opposite to the upper side31as motor connection bores48for supplying power to the electric motor16of the power brake pressure generator5. The motor connection bores48are provided in the hydraulic block25on an imaginary arc around the cylinder18between the cylinder18and the underside47.

The hydraulic block25also has a signal bore49for control lines and/or signal lines to or from the electric motor16. A rotation angle sensor50of the electric motor16, for instance, can be connected to the electronic control unit disposed in the control unit cover39on the valve side26of the hydraulic block25via said signal bore49. The signal bore49extends through from the valve side26to the motor side27and is disposed between the cylinder18of the power brake pressure generator5and a corner of the hydraulic block25between the fastening side46and the underside47of the hydraulic block25.

The receptacles for the solenoid valves are disposed in the valve side26of the hydraulic block25. The receptacles21′ for the inlet valves21are provided side by side between a base of the connectors29for the brake fluid reservoir12and the master brake cylinder bore4′ and alternately with an offset of slightly less than their diameter in the direction of the upper side31and the master brake cylinder4in the valve side26.

Three of the receptacles22′ for the outlet valves22are provided side by side on an imaginary straight line parallel to the upper side Slat the height of the master brake cylinder bore4′ in the valve side26of the hydraulic block25. These three receptacles22′ for the outlet valves22are disposed in an axial plane of the master brake cylinder bore4′ or in a plane parallel to the axial plane of the master brake cylinder bore4′ that intersects the master brake cylinder bore4′. A first or last receptacle22′ for an outlet valve22is provided in the valve side26of the hydraulic block25offset in the direction of the upper side31of the hydraulic block25. The receptacle22′ closest to the fastening side46is offset to the other three receptacles22′ for the outlet valves22. The receptacles21′ for the inlet valves21and the receptacles22′ for the outlet valves22for a respective wheel brake2are offset to one another in pairs, i.e. perpendicular to the upper side31or parallel to the fastening side46of the hydraulic block25.

For each master brake cylinder piston53, the master brake cylinder bore4′ comprises two peripheral sealing grooves54in which piston seals (sealing rings)55are disposed. The sealing grooves54have only a small axial distance to one another that is approximately as large as the sealing grooves54are wide. The three receptacles22′ for the outlet valves22provided at the height of the master brake cylinder bore4′ communicate directly with the master brake cylinder bore4′ through lines that lead coaxially through a base of the receptacles22′ radially or in a secant direction into the master brake cylinder bore4′. One of the receptacles22′ for one of the outlet valves22between two of the sealing grooves54is connected to the master brake cylinder bore4′.

A receptacle13′ for the test valve13is provided in the valve side26of the hydraulic block25between the receptacles22′ for the outlet valves22that are offset relative to the others and the fastening side46of the hydraulic block25.

A flat counterbore is provided in the valve side26of the hydraulic block25in a center between the receptacles22′ for the outlet valves22as a receptacle24′ for the pressure sensor24for the cylinder18of the power brake pressure generator5. It communicates via a coaxial bore in its base with the line20that leads from the center connector29for the brake fluid reservoir12to the cylinder18of the power brake pressure generator5.

A receptacle23′ for the pressure sensor23of the master brake cylinder4is provided in the valve side26of the hydraulic block25slightly below the master brake cylinder bore4′ and near its closed end. The receptacle23′ for the pressure sensor23communicates directly with the master brake cylinder bore4′ via a line that extends coaxially through the base of the receptacle23′ in a secant direction into the master brake cylinder bore4′.

A receptacle6′ for one of the two separator valves6is provided in the valve side26of the hydraulic block25between the receptacle23′ for the pressure sensor23of the master brake cylinder4and the cylinder18of the power brake pressure generator5. The receptacle6′ for the other power valve6is provided in the valve side26of the hydraulic block25on an opposite side of the cylinder18of the power brake pressure generator5between the cylinder18and the fastening side46of the hydraulic block25.

Receptacles7′ for the power valves7are provided in the valve side26of the hydraulic block25on opposite sides of the cylinder18of the power brake pressure generator5. One of the two receptacles7′ is located between the receptacle23′ for the pressure sensor23of the master brake cylinder4and the other receptacle7′ on the opposite side of the cylinder18between said cylinder and the fastening side46of the hydraulic block25. The two receptacles7′ for the power valves7communicate with the cylinder18of the power brake pressure generator5via a line52that extends through the hydraulic block25parallel to the upper side31and perpendicular to the fastening side46of the hydraulic block25.

A receptacle8′ for the simulator valve8is located between the receptacle23′ for the pressure sensor23of the master brake cylinder4and the cylinder bore28of the pedal travel simulator11offset to the cylinder bore28in the direction of the side38of the hydraulic block25comprising the depression37.