HYDRAULIC BLOCK FOR A SERVICE BRAKE UNIT OF A HYDRAULIC POWER BRAKE SYSTEM

Description

[0001] The invention relates to a hydraulic block for a service brake unit of a hydraulic power brake system for an autonomously driving motor vehicle having the features of the preamble of claim 1. State of the art

[0002] Autonomous driving up to Level 4 (driver can be requested to intervene) and Level 5 (highest level; no driver required) requires a power braking system with redundancies that almost certainly excludes a complete failure of the vehicle braking system without the need for driver intervention.

[0003] International patent application WO 2012 / 143 312 A1 discloses an electro-hydraulic power brake system for a motor vehicle with a service brake unit and a brake pressure control unit. The service brake unit has a muscle-power-operated master brake cylinder and a piston-cylinder unit, whose piston is displaceable within a cylinder by an electric motor via a screw drive, as a power brake pressure generator, which is hydraulically connected in parallel to the master brake cylinder. The brake pressure control unit has solenoid valves and a hydraulic pump in each brake circuit for individual wheel brake pressure control. The brake pressure control unit is connected to the service brake unit, and hydraulic wheel brakes are connected to the brake pressure control unit.

[0004] The published patent application DE 10 2016 202 113 A1 discloses a narrow, cuboid-shaped hydraulic block for a hydraulic unit of a slip-controlled, hydraulic power brake system with three connections for a brake fluid reservoir in the upper side of the hydraulic block. Below the connections, a master brake cylinder bore extends continuously through the hydraulic block parallel to the upper side from one narrow side to an opposite narrow side adjacent to the upper side. Below the master brake cylinder bore, a power cylinder bore extends transversely to the master brake cylinder bore from one large side of the hydraulic block to an opposite large side, which are adjacent to the upper side and the two narrow sides of the hydraulic block. To generate brake pressure using external power, an external power piston with an electric motor is displaceable in the external power cylinder bore via a ball screw drive.The electric motor is arranged coaxially with the external power cylinder bore on the outside of the hydraulic block, and the ball screw is located between the electric motor and the external power piston, also coaxial with the electric motor and the external power cylinder bore. The electric motor and the ball screw form an external power drive and, together with the external power piston and the external power cylinder bore, form an external power brake pressure generator for the vehicle's hydraulic braking system. Connections for hydraulic wheel brakes via brake lines are located near the top, at the level of the connections for the brake fluid reservoir, in one of the two large sides of the hydraulic block. Disclosure of the invention

[0005] The hydraulic block according to the invention with the features of claim 1 is intended for a service brake unit of a hydraulic power brake system with brake pressure control. 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 connected to the hydraulic block. Brake pressure control can, in particular, also include slip control. Slip control systems include, for example, anti-lock brakes, traction control, and / or vehicle dynamics control systems, for which the abbreviations ABS, ASR, and / or FDR are commonly used. Slip control systems are known and will not be discussed here.

[0006] The hydraulic block serves to mechanically attach and hydraulically interconnect hydraulic components of the vehicle braking system, brake pressure generation and / or brake pressure control and / or slip control. Such hydraulic components include solenoid valves, check valves, hydraulic accumulators, damper chambers, and pressure sensors. The hydraulic components are mounted in receptacles in the hydraulic block, which are usually designed as cylindrical counterbores, blind holes, or through holes, sometimes with stepped diameters. "Interconnected" means that the receptacles or the hydraulic components mounted in them are connected by lines in the hydraulic block according to a hydraulic circuit diagram of the vehicle braking system. However, the lines are typically not necessarily drilled into the hydraulic block.

[0007] Equipped with the hydraulic components of the vehicle braking system or its slip control, the hydraulic block forms the service brake unit, where "equipped" means that the hydraulic components are fastened in the respective receptacles of the hydraulic block.

[0008] In addition, the hydraulic block has connections for brake lines that lead to hydraulic wheel brakes of the vehicle's braking system.

[0009] For autonomous driving up to levels 4 and 5, the invention provides for a connection of an auxiliary brake unit to the service brake unit. Level 4 is also referred to as highly automated driving and means that control of a vehicle is permanently taken over by an electronic system, and a driver is only prompted to intervene when the system can no longer handle the driving tasks. Level 5 is also referred to as full automation and does not require a driver. For this purpose, the hydraulic block of the service brake unit has connections for brake lines leading to and from the auxiliary brake unit. The auxiliary brake unit has an external brake pressure generator for generating hydraulic brake pressure in the event of a failure of the external brake pressure generator of the service brake unit. The invention is also usable for autonomous driving with lower levels and for non-autonomous driving.

[0010] The invention is particularly directed to the arrangement of the hydraulic components or their receptacles and their hydraulic interconnection in the hydraulic block.

[0011] The hydraulic block according to the invention has a top surface designed for mounting a brake fluid reservoir. The top surface of the hydraulic block has one or more connections for the brake fluid reservoir.

[0012] A mounting side of the hydraulic block, adjacent to the top of the hydraulic block, is designed to attach the hydraulic block or the service brake unit—that is, the hydraulic block equipped with the hydraulic components of the vehicle's braking system—to a firewall of a motor vehicle. For this purpose, the hydraulic block has, for example, two standardized internally threaded holes on the mounting side, into which stud bolts or studs can be screwed to attach the hydraulic block or the service brake unit to the firewall of the motor vehicle.A master brake cylinder bore opens on the mounting side of the hydraulic block, so that a master brake cylinder piston can be moved in the master brake cylinder bore using muscle power via a brake pedal mounted opposite the hydraulic block on the bulkhead of the motor vehicle via a pedal rod which connects the brake pedal to the master brake cylinder piston in an articulated manner.

[0013] A power cylinder bore for generating brake pressure using external power is arranged transversely to the master brake cylinder bore between the top of the hydraulic block and the master brake cylinder bore in the hydraulic block. The master brake cylinder bore is therefore located below the power cylinder bore, meaning the master brake cylinder bore is located on a side of the power cylinder bore facing away from the top of the hydraulic block, or between the power cylinder bore and a bottom side of the hydraulic block opposite the top.

[0014] Connections for connecting hydraulic wheel brakes and the auxiliary brake unit via brake lines are mounted on the motor side of the hydraulic block according to the invention. The motor side is adjacent to the top and the mounting side of the hydraulic block and is intended for the attachment of an electric motor for driving the external brake pressure generator. Three connections for wheel brakes are mounted on the motor side near a side of the hydraulic block opposite the mounting side. "Near" means a distance of preferably no more than one diameter of the connections.

[0015] A connection for a brake line to or from the auxiliary brake unit is mounted on the engine side, extending from an axis of the power cylinder bore at an angle of approximately 45° to the top of the hydraulic block, obliquely upwards or downwards toward a side of the hydraulic block opposite the mounting side. One or more connections for the auxiliary brake unit can also be mounted near the bottom of the engine side of the hydraulic block.

[0016] Through holes or blind holes in the hydraulic block, referred to here as "lines" or "bores" or as "cylinder bores", can also be produced by means other than drilling.

[0017] One embodiment of the invention provides a receptacle for a check valve, through which a brake line leading to the auxiliary brake unit is connected to the brake fluid reservoir, concentrically in or to one of the connections for the brake fluid reservoir.

[0018] The dependent claims relate to further developments and advantageous embodiments of the invention specified in the independent claim.

[0019] All features disclosed in the description and the drawings can be implemented individually or in any combination in embodiments of the invention. Embodiments of the invention that do not include all, but only one or more, features of a claim or embodiment of the invention are generally possible. For example, embodiments of the invention are also possible in which the connections for the auxiliary brake unit are arranged at a location other than that specified in claim 1. Short description of the drawing

[0020] The invention is explained in more detail below with reference to an embodiment illustrated in the drawing. In the drawings: Figure 1 a hydraulic circuit diagram of a service brake unit of an electro-hydraulic power brake system according to the invention; Figure 2a hydraulic circuit diagram of an auxiliary brake unit of the electro-hydraulic power brake system Figure 1 ; Figure 3 a view of an engine side of a hydraulic block according to the invention of the service brake unit of the vehicle brake system according to Figure 1 ; Figure 4 a view of a valve side of the hydraulic block opposite the engine side Figure 3 ; and Figure 5 , 5a , 6 and 7 Parts of a bore of the hydraulic block from Figure 3 and 4 .

[0021] The drawings are partly simplified representations. Embodiment of the invention

[0022] The Figure 1 and 2The electrohydraulic power brake system 1 according to the invention shown is intended for a passenger car driving autonomously up to level 4 or 5. Level 4 means autonomous driving, where a driver can be requested to intervene, and level 5, the highest level, means autonomous driving that does not require any driver intervention.

[0023] The externally powered braking system 1 comprises a service brake unit 2 and an auxiliary brake unit 3. The service brake unit 2 is designed to apply the brakes, and the auxiliary brake unit 3 is designed to apply the brakes in the event of a fault or failure of the service brake unit 2. Hydraulic wheel brakes 4 are connected to the service brake unit 2 via brake lines - four in the exemplary embodiment. The auxiliary brake unit 3 is connected to the service brake unit 2 via brake lines in such a way that the wheel brakes 4 can also be applied with the auxiliary brake unit 3. The service brake unit 2 and the auxiliary brake unit 3 are each separate assemblies, with the service brake unit 2 being attached to a bulkhead of the passenger car, and the auxiliary brake unit 3 being able to be arranged at any desired location on the passenger car.The brake lines that connect the auxiliary brake unit 3 to the service brake unit 2 are hereinafter also referred to as supply lines V1, V2 and return lines R1, R2.

[0024] The vehicle brake system 1 according to the invention is designed as a dual-circuit brake system, and its brake units 2, 3 are designed as dual-circuit brake units. Two wheel brakes 4 are assigned to each brake circuit. The auxiliary brake unit 3 is connected to the service brake unit 2 in each brake circuit via a supply line V1, V2 and a return line R1, R2. The connection points of the supply lines V1, V2 and the return lines R1, R2 are designated V1, V2, R1, and R2 in the service brake unit 2 and the auxiliary brake unit 3.

[0025] The service brake unit 2 has a piston-cylinder unit 5, whose piston 6 is displaceable in a cylinder 9 by an electric motor 7 via a screw drive 8 as a rotation / translation converter gear. The electric motor 7, the screw drive 8, and the piston-cylinder unit 5 form an externally powered brake pressure generator 10 of the service brake unit 2 for generating brake pressure for service braking. Service braking is the usual and intended brake application.

[0026] The external brake pressure generator 10 is connected to the two brake circuits via service brake valves 11 between isolation valves 12 and inlet valves 13.

[0027] The service brake unit 2 has an inlet valve 13 and an outlet valve 14 for each wheel brake 4, with which the wheel brake pressures in each wheel brake 4 can be individually regulated. This allows the wheel brake pressures in the wheel brakes 4 and thus the braking forces of the wheel brakes 4 to be regulated during normal driving without slippage. Furthermore, slip control systems such as anti-lock and traction control, vehicle dynamics control systems, also colloquially referred to as anti-skid control systems, automatic braking, distance control, and the like are possible. Such control systems are known and will not be explained in detail here. The inlet valves 13 and the outlet valves 14 can also be regarded as wheel brake pressure control valve assemblies 13, 14.

[0028] In addition to the external brake pressure generator 10, the service brake unit 2 has a muscle-power-operated master brake cylinder 15, to which the wheel brakes 4 are connected via the isolating valves 12 and the inlet valves 13. The service brake unit 2 has an isolating valve 12 in each brake circuit and an inlet valve 13 and an outlet valve 14 for each wheel brake 4. The master brake cylinder 15 serves as a setpoint generator for the wheel brake pressures to be set in the wheel brakes 4 during service braking in the case of driver operation. The brake pressure is generated both in driver operation and during autonomous driving with the external brake pressure generator 10. The master brake cylinder 15 is hydraulically separated from the wheel brakes 4 during service braking by closing the isolating valves 12.

[0029] As mentioned, the master brake cylinder 15 serves as a setpoint transmitter for the wheel brake pressures during service braking by the driver, where the brake pressure is generated by the external brake pressure generator 10 of the service brake unit 2. If the external brake pressure generator 10 fails, the brake pressure can be generated by actuating the master brake cylinder 15. This is a so-called auxiliary braking with muscle power, and the master brake cylinder 15 can therefore also be considered a muscle-powered brake pressure generator.

[0030] To displace brake fluid from the master brake cylinder 15 when the isolation valves 12 are closed and to move the piston of the master brake cylinder 15 and a brake pedal 16, the service brake unit 2 has a pedal travel simulator 17, which is connected to a brake circuit of the master brake cylinder 15 via a simulator valve 18. The pedal travel simulator 17 is a piston-cylinder unit with a spring-loaded or, for example, gas-pressure-loaded piston.

[0031] In the described and illustrated embodiment of the invention, the isolation valves 12 and the inlet valves 13 are open 2 / 2-way solenoid valves in their de-energized basic positions and the service brake valves 11 of the external brake pressure generator 10, the outlet valves 14 and the simulator valve 18 are closed 2 / 2-way solenoid valves in their de-energized basic positions.

[0032] The hydraulic components of the service brake unit 2 of the electro-hydraulic power brake system 1 according to the invention, namely the valves 11, 12, 13, 14, 18, the power brake pressure generator 10, the master brake cylinder 15, the pedal travel simulator 17 and other components such as pressure sensors are arranged in receptacles of a hydraulic block 19 of the service brake unit 2 and are connected to one another by a bore in the hydraulic block 19 in accordance with the drawn hydraulic circuit diagram of the vehicle brake system 1 or the service brake unit 2.

[0033] A pressureless brake fluid reservoir 20, as known from conventional master brake cylinders, is mounted on the hydraulic block 19, and the master brake cylinder 15 and, via a check valve 28, the external brake pressure generator 10 are connected to it. In one of the two brake circuits, a test valve 21 is provided between the brake fluid reservoir 20 and the master brake cylinder 15. In the exemplary embodiment, the test valve 21 is also a 2 / 2-way solenoid valve that is open in its de-energized basic position. A check valve 29, through which fluid can flow in the direction of the master brake cylinder 15, is hydraulically connected in parallel to the test valve 21; however, this check valve is not present in all embodiments of the invention.

[0034] The auxiliary brake unit 3 has a hydraulic pump 22 in each of its two brake circuits, which can be driven by a common electric motor 23. The hydraulic pumps 22 are piston pumps, although other hydraulic pumps, such as gear pumps, are also possible. The hydraulic pumps 22, together with the electric motor 23, form externally powered brake pressure generators 24.

[0035] The suction sides of the hydraulic pumps 22 of the auxiliary brake unit 3 are connected to the two brake circuits of the master brake cylinder 15 of the service brake unit 2 via suction valves 25 and the aforementioned brake lines, namely the supply lines V1, V2, by means of which the auxiliary brake unit 3 is connected to the service brake unit 2. The pressure sides of the hydraulic pumps 22 of the auxiliary brake unit 3 are connected to the two brake circuits of the master brake cylinder 15 of the service brake unit 2 via pressure valves 26 and the supply lines V1, V2. In addition, the pressure sides of the hydraulic pumps 22 of the auxiliary brake unit 3 are connected to the isolation valves 12 of the service brake unit 2 via brake lines, namely the return lines R1, R2, through which the auxiliary brake unit 3 is connected to the service brake unit 2.This allows the wheel brakes 4 to be actuated by generating brake pressure with the hydraulic pumps 22 of the auxiliary brake unit 3, which form its external brake pressure generator 24. Wheel brake pressures in the wheel brakes 4 can be regulated with the inlet valves 13 and the outlet valves 14 of the service brake unit 2, which form the wheel brake pressure control valve assemblies, provided these valves 13, 14 and their controls are functional. The hydraulic pumps 22 of the auxiliary brake unit 3, which form the external brake pressure generator 24, generate the brake pressure in the event of a fault or failure of the service brake unit 2. Such braking is referred to as auxiliary braking.

[0036] In the described and illustrated embodiment of the invention, the suction valves 25 of the auxiliary brake unit 3 are designed as 2 / 2-way solenoid valves that are closed in their de-energized basic positions, and the pressure valves 26 are designed as 2 / 2-way solenoid valves that are open in their de-energized basic positions. During auxiliary braking, the suction valves 25 are opened so that the hydraulic pumps 22 of the auxiliary brake unit 3 can draw brake fluid from the brake fluid reservoir 20 of the service brake unit 2 through the master brake cylinder 15. Furthermore, the pressure valves 26 are closed to apply braking pressure to the wheel brakes 4.

[0037] During service braking, the wheel brakes 4 are acted upon by a brake pressure generated by the external brake pressure generator 10 of the service brake unit 2 through the open pressure valves 26 of the auxiliary brake unit 3 and the service brake valves 11 of the service brake unit 2, which are to be opened in this case, or by a brake pressure generated by the external brake pressure generator 10 through the open pressure valves 26 of the auxiliary brake unit 3 and the open isolating valves 12 of the service brake unit 2.

[0038] For rapid brake pressure buildup during auxiliary braking, the hydraulic pump 22 of the external brake pressure generator 24 of the auxiliary brake unit 3 is connected to the brake fluid reservoir 20 of the service brake unit 2 via a check valve 30 in one brake circuit. In the exemplary embodiment, the check valve 30 is arranged in the hydraulic block 19 of the service brake unit 2. Preferably, the hydraulic pump 22 of a primary circuit is connected to the brake fluid reservoir 20 via the check valve 30, but it is also possible to connect the hydraulic pump 22 of a secondary circuit to the brake fluid reservoir 20 via a check valve 30, or both brake circuits to the brake fluid reservoir 20 via a check valve 30 each (not shown). The primary circuit is the brake circuit that is actuated directly via a pedal rod with the brake pedal 16.

[0039] The hydraulic components of the auxiliary brake unit 3, namely the hydraulic pumps 22, the valves 25, 26 and other components such as pressure sensors, are arranged in a hydraulic block 27 of the auxiliary brake unit 3 and are connected to one another by a bore in the hydraulic block 27 in accordance with the hydraulic circuit diagram shown, which can also be referred to as the interconnection of the hydraulic components 22, 25, 26.

[0040] The brake fluid reservoir 20 has a chamber 31', 31‴ for each brake circuit and an additional chamber 31" for the external brake pressure generator 10 of the service brake unit 2, thus a total of three chambers 31', 31", 31‴. The check valve 30, through which a hydraulic pump 22 of the auxiliary brake unit 3 is connected to the brake fluid reservoir 20, is connected to the same chamber 31' of the brake fluid reservoir 20 as the test valve 21. The hydraulic pumps 22 of the auxiliary brake unit 3 are connected to different chambers 31', 31‴ of the brake fluid reservoir 20. The external brake pressure generator 10 of the service brake unit 2 is connected to a separate chamber 31" or to a different chamber 31" of the brake fluid reservoir 20 than the hydraulic pumps 22 of the auxiliary brake unit 3.

[0041] Figure 3 shows an engine side 32 and Figure 4a valve side 33 of the hydraulic block 19 of the service brake unit 2. In the exemplary embodiment, the hydraulic block 19 is a flat, cuboid-shaped metal block that serves for the mechanical attachment and hydraulic connection of the hydraulic components of the vehicle brake system 1. Equipped with the hydraulic components, the hydraulic block 19 forms the service brake unit 2 of the vehicle brake system 1. "Flat" means that the hydraulic block 19 is approximately three to four times as wide or long as it is thick. Two opposite large sides of the hydraulic block 19 are almost square in the exemplary embodiment and form the motor side 32 and valve side 33. In Figure 3 and 4 the hydraulic block 19 is shown unequipped, i.e. without the hydraulic components.

[0042] A narrow side of the hydraulic block 19, which is referred to here as the upper side 34, has three cylindrical blind holes as connections 20' for the brake fluid reservoir 20, which is arranged on the upper side 34 of the hydraulic block 19 (cf. Fig. 6 ). Connection nipples on a bottom of the brake fluid reservoir 20 enter the blind holes of the hydraulic block 19 forming the connections 20' and are sealed there with O-rings.

[0043] In the hydraulic block 19, a master cylinder bore 15', which forms the master cylinder 15, is arranged parallel to the top side 34 and in a center between the motor side 32 and the valve side 33. In Figure 3 and 4The master brake cylinder bore 15' is shown with dashed lines. In the exemplary embodiment, it is located slightly below a center of the hydraulic block 19 between the top side 34 and an opposite bottom side 35 of the hydraulic block 19, so that the master brake cylinder bore 15' lies approximately tangentially on a center plane of the hydraulic block 19 between the top side 34 and the bottom side 15.

[0044] An external power cylinder bore 9', which forms the cylinder 9 of the external power brake pressure generator 10, is mounted perpendicular to the master brake cylinder bore 15' in the motor side 32 of the hydraulic block 19 and projects on the valve side 33 as a type of dome 49. The external power cylinder bore 9' is located slightly above the master brake cylinder bore 15', i.e., between the master brake cylinder bore 15' and the top side 34 of the hydraulic block 19. The external power cylinder bore 19 extends past the master brake cylinder bore 15' at a short distance. It is arranged slightly off-center, offset toward a mounting side 36 of the hydraulic block 19.

[0045] The electric motor 7 of the external brake pressure generator 10, which is Figure 3not shown, is arranged coaxially to the external power cylinder bore 9' on the outside of the motor side 32 of the hydraulic block 19. A planetary gear as a reduction gear and the screw drive 8, which in the exemplary embodiment is a ball screw drive, are arranged coaxially to the external power cylinder bore 9' between the electric motor 7 and the piston 6 of the external power brake pressure generator 10 (in Figure 3 not drawn)

[0046] The fastening side 36 is a narrow side of the hydraulic block 19, at which the master brake cylinder bore 15' is open. The fastening side 36 borders the top side 34, the bottom side 35, the motor side 32, and the valve side 33 and is intended for fastening the hydraulic block 19 to a firewall (not shown) of a motor vehicle. The hydraulic block 19 is fastened to the firewall of the motor vehicle such that the top side 34 with the brake fluid reservoir 31 is at the top. The master brake cylinder bore 15' is open on the fastening side 36 of the hydraulic block 19, so that a master brake cylinder piston can be displaced in the master brake cylinder bore 15' by means of a foot brake pedal, which is fastened to an opposite side of the firewall, via a pedal rod that pivotally connects the master brake cylinder piston to the foot brake pedal.

[0047] A cylinder bore 17' of the pedal travel simulator 17 is arranged in the valve side 33 of the hydraulic block 19, parallel to the power cylinder bore 9' and perpendicular to the master brake cylinder bore 15'. In the exemplary embodiment, the cylinder bore 17' is located between the master brake cylinder bore 15' and the top side 34 of the hydraulic block 19, closer to the top side 34 than to the master brake cylinder bore 15', and between the power cylinder bore 9' and a narrow side 48 of the hydraulic block 19 opposite the mounting side 36.

[0048] Receptacles for the solenoid valves 12, 13, 14, 18 and receptacles for other components such as pressure sensors are mounted in the valve side 33 of the hydraulic block 19. The receptacles, which are located in Figure 4The holes, designated with the reference number of the respective solenoid valve or other component, are cylindrical, partially diameter-stepped countersinks or blind holes in the hydraulic block 19. The hydraulic components are inserted into the receptacles and caulked all around to ensure pressure-tightness. Hydraulic sections of the solenoid valves 12, 13, 14, and 18, forming the actual valves, are located in the receptacles. Armatures and solenoid coils, which are housed in a valve dome, protrude from the valve side 33 of the hydraulic block 19.

[0049] The hydraulic block 19 of the service brake unit 2 is designed according to the Figure 1The term "drilled" refers to the cylinder bores, receptacles for the solenoid valves, and connection bores in the hydraulic block 19, as well as the bores connecting them and forming lines according to the hydraulic circuit diagram. The hydraulic block 19 is drilled Cartesian-style, meaning the bores, receptacles, connections, lines, etc., are arranged parallel and perpendicular to each other and to the sides and edges of the hydraulic block 19. This does not exclude individual, diagonally running lines and bores.

[0050] The auxiliary brake unit 3 is connected to the hydraulic block 19 of the service brake unit 2 by four brake lines: the two supply lines and the two return lines. The four wheel brakes 4 are also connected to the hydraulic block 19 of the service brake unit 2 by brake lines. For connection purposes, the hydraulic block 19 has blind holes, referred to here as connections V1', V2', R1', R2', 4'. The connections V1', V2', R1', R2', 4' are located on the motor side 32 of the hydraulic block 19. The brake lines are attached to the connections in a pressure-tight manner using press-in nipples (not shown) using a so-called self-clinching technique. The brake lines can also be connected using screw nipples, for example.

[0051] A line 51 designed as a bore connects the connection R1' for the return line R1 of the primary circuit with the receptacle 12' for the isolating valve 12. This line 51 leads as in Figure 6as seen coaxially from the bottom of the connection R1' for the return line R1 to a center of the hydraulic block 19 between the motor side 32 and the valve side 33 and then after a bend in the direction of the fastening side 36 further in a center plane of the hydraulic block 19 in the middle between the motor side 32 and the valve side 33, until after a further bend near the fastening side 36 it leads downwards in the direction of the master brake cylinder bore 15', from where the line 51 opens coaxially into the receptacle 12' for the isolating valve 12 after a further bend.

[0052] From the connection R2' for the return line R2 of the secondary circuit, as shown in Figure 7can be seen a line 52 also in the center plane of the hydraulic block 19 between the motor side 32 and the valve side 33 parallel to the underside 35 of the hydraulic block 19 in the direction of the narrow side 48 opposite the fastening side 36 and after an upward bend to the receptacle 12' for the isolating valve 12.

[0053] Three connections 4' for brake lines leading to three wheel brakes 4 are located along the narrow side 48 opposite the mounting side 36 in the motor side 32, and one connection 4' for a fourth wheel brake 4 is located offset from the narrow side 48 near the underside 35 of the hydraulic block 19 in the motor side 32. "Near" means a distance of no more than one radius of the respective connection.

[0054] Two connections R2', V1' for the auxiliary brake unit 3 are also arranged close to the underside 35 and two further connections V2', R1' are arranged offset in the hydraulic block 19 from an axis of the external power cylinder bore 9' at an angle of approximately 45° in the direction of the upper side 34 and in the direction of the underside 35 and in the direction of the narrow side 48 opposite the fastening side 36.

[0055] Between the external power cylinder bore 9' and the top side 34, three through holes extending from the motor side 32 to the valve side 33 are provided as motor connection bores 37 for a power supply of the electric motor 7 of the external power brake pressure generator 10 in the hydraulic block 19. The motor connection bores 37 are arranged on an imaginary arc around the external power cylinder bore 9' between the external power cylinder bore 9' and the top side 34 in the hydraulic block 19. Also arranged on the imaginary arc on which the motor connection bores 37 are arranged is a signal bore 38 for control lines and / or signal lines to or from the electric motor 7 in the hydraulic block 19.

[0056] Figure 5 shows a part of the bore of the hydraulic block 19 according to the invention of the service brake unit 2 of the electro-hydraulic power brake system 1. In Figure 5 and also in Figure 6 and 7the hydraulic block 19 is transparent and only a part of the bore of the hydraulic block 19 is drawn. Figure 5 shows a connection of one of the connections 20' for the brake fluid reservoir 20 in the top 34 of the hydraulic block 19 with the connection V1' for the one feed line V1 to the auxiliary brake unit 3. Figure 5shows a view of the motor side 32 of the hydraulic block 19, the fastening side 36 is on the left. A line 39, designed as a bore or as several bores at right angles to one another and parallel or perpendicular to the sides of the hydraulic block 19, initially leads coaxially from a base of the connection 20' for the brake fluid reservoir 20 downwards between the external power cylinder bore 9' and the cylinder bore 17' of the pedal travel simulator 17 to below, i.e. to a side of the cylinder bore 17' of the pedal travel simulator 17 facing the underside 35 of the hydraulic block 19. Below the cylinder bore 17', the line 39 continues in the direction of the narrow side 48 of the hydraulic block 19 opposite the fastening side 36, and then bends downwards again at a right angle below the cylinder bore 17' towards the underside 35 of the hydraulic block 19.This downward-leading portion of line 39 to the supply line passes the master brake cylinder bore 15' on the motor side 32 of the hydraulic block 19. Approximately midway between the master brake cylinder bore 15', the line 39 bends back at a right angle toward the mounting side 36 and then, with a final section leading downwards toward the underside 35, opens into the connection V1' for the supply line, which is located approximately midway between the mounting side 36 and the opposite narrow side 48 near the underside 35 in the motor side 32 of the hydraulic block 19.

[0057] The Figure 5The check valve 30, shown as a circuit symbol, in the line 39 leading from the brake fluid reservoir 20 to the feed line is located in a receptacle 30' which, as a smaller-diameter extension, is attached coaxially to a base of the blind hole which forms the connection 20' for the brake fluid reservoir 20.

[0058] Instead of passing the master brake cylinder bore 15', the line 39 from the brake fluid reservoir 20 to the feed line V1 can also lead from the holder 20' for the brake fluid reservoir 20 downwards in the direction of the master brake cylinder bore 15', after a bend parallel to the master brake cylinder bore 15' in the direction of the narrow side 48 opposite the fastening side 36, after a further bend again downwards in the direction of the master brake cylinder bore 15' and again after a bend parallel to the master brake cylinder bore 15' back in the direction of the fastening side 36 to approximately a middle of the hydraulic block 19 between the fastening side 36 and the opposite narrow side 48 of the hydraulic block 19. From there, the line 39 leads through the master brake cylinder bore 15' downwards to the connection V1' of the feed line V1.In this embodiment of the invention, the master brake cylinder bore 15' has an approximately semicircular undercut 40, which extends around a master brake cylinder piston / secondary piston 53 on an inner side of the master brake cylinder bore 15'. This alternative line routing is shown in FIG. Figure 5a . The master cylinder piston / secondary piston 53 closes the undercut 40 on its inside so that it does not communicate with the master cylinder bore 15'. A master cylinder piston / primary piston 54 and the secondary piston 53 are schematically shown in Figure 5 and 5a marked.

[0059] For the purpose of so-called "thermal relief," the rear side of a simulator piston (not shown) of the pedal travel simulator 17 communicates with the unpressurized brake fluid reservoir 20. The rear side of the simulator piston is the side that is not pressurized when the master brake cylinder 15 is actuated. "Thermal relief" means that brake fluid is not trapped on the rear side of the simulator piston, but that, when the volume increases upon heating, brake fluid can flow from the rear side of the simulator piston into the brake fluid reservoir 20. In the exemplary embodiment, the thermal relief of the simulator piston or the pedal travel simulator 17 is achieved via a line 41 that leads from the base of one of the connections 20' for the brake fluid reservoir 20 in the top side 34 of the hydraulic block 19 downwards to the cylinder bore 17' of the pedal travel simulator 17.In the exemplary embodiment, the line 41 is drilled at an angle, i.e. not parallel or at right angles to the sides and edges of the hydraulic block 19.

[0060] The connection of a chamber of the master brake cylinder 15, in the exemplary embodiment a secondary chamber, to the brake fluid reservoir 20 takes place in the exemplary embodiment on the rear side of the simulator piston through the cylinder bore 17' of the pedal travel simulator 17. From this bore, a line 42 leads downward to a circumferential groove 43 of the master brake cylinder bore 15', which encloses a master brake cylinder piston (not shown), in the exemplary embodiment a so-called secondary piston or floating piston. The groove 43 is sealed on both sides to the master brake cylinder piston by sealing rings (not shown), which are arranged in circumferential sealing grooves 44 of the master brake cylinder bore 15' on both sides of the groove 43.If the master brake cylinder piston moves over the groove 43 when the master brake cylinder 15 is actuated, it hydraulically separates the master brake cylinder 15 from the brake fluid reservoir 20, so that a further displacement of the master brake cylinder piston generates brake pressure in the master brake cylinder 15.

[0061] A first vent line 45 for the master brake cylinder 15 is connected to the master brake cylinder bore 15 at a circumferential point facing the top side 34 of the hydraulic block 19. This means that the vent line 45 opens into the top of the master brake cylinder bore 15' when the hydraulic block 19 is arranged with its top side 34 facing upwards, as intended. Any air bubbles contained in the brake fluid collect there, allowing the master brake cylinder 15 to be vented. In the exemplary embodiment, the first vent line 45 leads tangentially from the circumferential point of the master brake cylinder bore 15' facing the upper side 34 of the hydraulic block 19 in the direction of the motor side 32 and, after bending downwards, continues between the motor side 32 and the master brake cylinder bore 15' until, after bending further in the direction of the fastening side 36, it leads into one of the two connections V2' for the feed line to the auxiliary brake unit 3.In the exemplary embodiment, the vent line 45 opens into the secondary chamber of the master brake cylinder 15. Between its two bends, the first vent line 45 runs obliquely to the motor side 32 and to the valve side 33; it is located at the level of the master brake cylinder bore 15' near the motor side 32 and near the underside 35 of the hydraulic block 19 near the valve side 32. The invention does not exclude a parallel or perpendicular course of the vent line 45 to the sides and edges of the hydraulic block 19.

[0062] For possible venting of a primary chamber of the master brake cylinder 15, a second vent line 50 is arranged parallel to and close to the master brake cylinder bore 15' in the hydraulic block 19, which opens at the narrow side 48 of the hydraulic block 19 opposite the fastening side 36. The second vent line 50 is located approximately at the level of the circumferential point of the master brake cylinder bore 15' facing the top side 34 of the hydraulic block 19 on a side of the master brake cylinder bore 15' facing the engine side 32 and, after bending, opens tangentially into the master brake cylinder bore 15' at the circumferential point facing the top side 34 of the hydraulic block 19. The second vent line 50 crosses the line 39, which connects the connection 20' for the brake fluid reservoir 20 with the connection V1' for the supply line V1 to the auxiliary brake unit 3.

[0063] A receptacle 21' for the test valve 21 is mounted near the mounting side 36 on a bottom side of the master cylinder bore 15' in the valve side 33 of the hydraulic block 19 (see Figure 6). An axis of the receptacle 21' for the test valve 21 runs tangentially to a circumferential point of the master brake cylinder bore 15' facing the underside 35 of the hydraulic block 19. In the exemplary embodiment, the test valve 21 is connected to the brake fluid reservoir 20 using a complex line routing due to the bore in the hydraulic block 19: a line 46 initially leads from the base of one of the connections 20' for the brake fluid reservoir 20 in the top side of the hydraulic block 34 downwards to a groove 47 which encloses the piston 6 of the external brake pressure generator 10 in the external brake cylinder bore 9. The groove 47 is sealed on both sides with sealing rings to the piston 6 of the external brake pressure generator 10, so that the line 46 does not communicate with the cylinder 9 of the external brake pressure generator 10.From the groove 47, the line 46 continues in the direction of the narrow side 48 of the hydraulic block 19 opposite the fastening side 36 and, after bending downwards, into the groove 43 in the master brake cylinder bore 15' which surrounds the master brake cylinder piston and which communicates with the receptacle 21' for the test valve 21 as described above.

Claims

1. Hydraulic block for a service brake assembly of a hydraulic external-force brake installation for an autonomously driving motor vehicle, wherein the hydraulic block (19) has a top side (34), which is intended for mounting of a brake fluid reservoir (20) and has connections (20') for the brake fluid reservoir (20), a fastening side (36), which adjoins the top side (34) and is configured for fastening of the hydraulic block (19) to a bulkhead of the motor vehicle and at which a master brake cylinder bore (15') opens out, a motor side (32), which adjoins the top side (34) and the fastening side (36) and on which there is able to be arranged an electric motor (7) for driving a piston (6) of an external-force brake pressure generator (10), and connections (4') for connection of hydraulic wheel brakes (4') and for connection of an auxiliary brake assembly (3) by way of brake lines to the service brake assembly (2) in the motor side (32), characterized in that an external-force cylinder bore (9') is provided in the motor side (32) of the hydraulic block (19) between the top side (34) and the master brake cylinder bore (15'), and in that the hydraulic block (19) has a connection (V2', R1') for the auxiliary brake assembly (3) on a side, directed away from the fastening side (36) of the hydraulic block (19), of the external-force cylinder bore (9') at an angle of approximately 45° to the top side (34) of the hydraulic block (19) from an axis of the external-force cylinder bore (9') and / or has a connection (V1', R2') for the auxiliary brake assembly (3) close to a bottom side (35), opposite the top side (34), in the motor side (32) of the hydraulic block (19).

2. Hydraulic block according to Claim 1, characterized in that one of the connections (20') for the brake fluid reservoir (20) in the top side (34) of the hydraulic block (19) has a concentric receptacle (30') for a check valve (30), from which a line (39) leads in the hydraulic block (19) to one of the connections (V2') for the auxiliary brake assembly (3).

3. Hydraulic block according to Claim 2, characterized in that the line (39) leads from the receptacle (30') for the check valve (30) laterally past the external-force cylinder bore (9'), away from the fastening side (36) after a bend below the cylinder bore (17') of the pedal travel simulator (17), laterally past the master brake cylinder bore (15') after a further bend below the cylinder bore (17') of the pedal travel simulator (17), onwards in the direction of the bottom side (35) of the hydraulic block (19), and, after another bend, back in the direction of the fastening side (36) of the hydraulic block (19) as far as the one connection (V2') for the auxiliary brake assembly (3), which is provided in the motor side (32) of the hydraulic block (19) close to the bottom side (35).

4. Hydraulic block according to one or more of Claims 1 to 3, characterized in that the master brake cylinder bore (15') has a helical groove (40) which is a constituent part of a line (39) in the hydraulic block (19) that connects one of the connections (20') for the brake fluid reservoir (20) in the top side (34) of the hydraulic block (19) to one of the connections (V2') for the auxiliary brake assembly (3) in the motor side (32) of the hydraulic block (19).

5. Hydraulic block according to one or more of the preceding claims, characterized in that a line (41) leads from one of the connections (20') for the brake fluid reservoir (20) to a rear side of a simulator piston into the cylinder bore (17') for a pedal travel simulator (17).

6. Hydraulic block according to one or more of the preceding claims, characterized in that a line (42) leads from the cylinder bore (17') of the pedal travel simulator (17) to a groove (43) in the master brake cylinder bore (15'), which groove surrounds a master brake cylinder piston.

7. Hydraulic block according to one or more of the preceding claims, characterized in that a venting line (45) communicates with the master brake cylinder bore (15') at a circumferential point which is directed towards the top side (34) of the hydraulic block (19).

8. Hydraulic block according to one or more of the preceding claims, characterized in that one of the connections (R1') for the auxiliary brake assembly (3) is provided in the motor side (32) of the hydraulic block (19) close to the top side (34), in that a line (51) leads from there in the direction of the fastening side (36) of the hydraulic block (19) and, after a bend close to the fastening side (36), in the direction of the bottom side (35) of the hydraulic block (19) to a receptacle (12') for an isolation valve (12), which is provided in a valve side (33), opposite the motor side (32), of the hydraulic block (19) approximately at the same height as the axis of the external-force cylinder bore (9').

9. Hydraulic block according to one or more of the preceding claims, characterized in that that a line (52) leads from the connection (R2') for the auxiliary brake assembly (3) close to the bottom side (35) in the motor side (32) of the hydraulic block (19) away from the fastening side (36) and, after a bend upwards, to a receptacle (12') for an isolation valve (12) in the valve side (33) of the hydraulic block (19).