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

Description

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

[0002] A hydraulic block having the features of the preamble of claim 1 is already known, for example, from US 2020 / 282968 A1. The invention differs from this hydraulic block in that the power cylinder bore and the simulator cylinder bore are arranged between the top side and the master brake cylinder bore in the hydraulic block, and in that a second return line in the hydraulic block leads from a receptacle for an outlet valve through the simulator cylinder bore to one of the connections for the brake fluid reservoir. As explained below, the invention simplifies the drilling of a hydraulic block.

[0003] Furthermore, the published patent application DE 10 2016 202 113 A1 describes 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 drive is located—also coaxial with the electric motor and the external power cylinder bore—between the electric motor and the external power piston. The electric motor and the ball screw drive form an external power drive and, together with the external power piston and the external power cylinder bore, an external power brake pressure generator for the hydraulic vehicle 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. A simulator cylinder bore for a pedal travel simulator of the external power braking system is located in a bottom side of the known hydraulic block, opposite the top. Disclosure of the invention

[0004] The hydraulic block according to the invention with the features of claim 1 is intended for a brake unit of a hydraulic power brake system for a motor vehicle, which has a brake pressure control 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 brake system connected to the hydraulic block. Brake pressure control can, in particular, also include a slip control system. 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.

[0005] 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.

[0006] Equipped with the hydraulic components of the vehicle's braking system or its slip control, the hydraulic block forms the braking unit, where "equipped" means that the hydraulic components are fastened in the respective receptacles of the hydraulic block.

[0007] The invention is particularly directed to a drilling of the hydraulic block, i.e. to a routing of lines between the hydraulic components or their receptacles in the hydraulic block.

[0008] 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.

[0009] A mounting side of the hydraulic block adjacent to the top of the hydraulic block is designed to attach the hydraulic block or the brake unit, i.e. the hydraulic block equipped with the hydraulic components of the vehicle 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 studs or stay bolts can be screwed to attach the hydraulic block or the brake unit to the firewall of the motor vehicle. A master brake cylinder bore opens out 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 firewall of the motor vehicle and via a pedal rod that articulates the brake pedal to the master brake cylinder piston.Preferably, the master cylinder bore runs parallel to the top in the hydraulic block.

[0010] A power cylinder bore for generating brake pressure using external force 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, i.e., 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 of the hydraulic block opposite the top. The power cylinder bore opens into a motor side of the hydraulic block adjacent to the top and the mounting side, which is intended for mounting an electric motor for driving a power brake pressure generator.

[0011] A simulator cylinder bore for a pedal travel simulator is also located transversely to the master cylinder bore between the top of the hydraulic block and the master cylinder bore, i.e., above the master cylinder bore in the hydraulic block. It preferably opens on a valve side of the hydraulic block opposite the engine side, which, like the engine side, is adjacent to the top and the mounting side.

[0012] According to the invention, a second return line in the hydraulic block leads from a receptacle for an outlet valve of the vehicle brake system through the simulator cylinder bore to one of the connections for the brake fluid reservoir. The return line is a line for brake fluid in the hydraulic block, created by drilling or other means. Preferably, the second return line leads from the receptacle for the outlet valve to the simulator cylinder bore and from the simulator cylinder bore diagonally toward the engine side to the connection for the brake fluid reservoir in the top of the hydraulic block. The second return line can also lead to the master brake cylinder.

[0013] The second return line is arranged in the hydraulic block such that it opens into the simulator cylinder bore on the rear side of a simulator piston. The simulator piston divides the simulator cylinder bore into a pressurizable working chamber on the front side of the simulator piston, which is connected to the master brake cylinder via a simulator valve, and a pressureless chamber on the rear side of the simulator piston, which communicates with the pressureless brake fluid reservoir. According to the invention, the second return line leads through the pressureless chamber of the simulator cylinder bore.

[0014] According to one embodiment of the invention, a first return line in the hydraulic block leads from a receptacle for an outlet valve to the power cylinder bore, and from the power cylinder bore to one of the connections for the brake fluid reservoir. The two return lines preferably connect different receptacles for outlet valves to different connections for the brake fluid reservoir. The first return line can be implemented independently of the routing of the second return line described above.

[0015] 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.

[0016] The dependent claims relate to further developments and advantageous embodiments of the invention specified in the independent claim.

[0017] 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

[0018] The invention is explained in more detail below with reference to an embodiment illustrated in the drawing. In the drawings: Figure 1 shows a hydraulic circuit diagram of an electro-hydraulic power brake system; Figure 2 shows an engine side of a hydraulic block according to the invention of a brake unit of the vehicle brake system from Figure 1; Figure 3a valve side of the hydraulic block opposite the motor side Figure 2 ; Figure 3a a section of the hydraulic block along the angled section line AA in Figure 3 ; Figure 3 shows a section of the hydraulic block along line BB in Figure 3 ; and Figure 4 shows part of a bore of the hydraulic block from Figure 2 and 3 .

[0019] The drawings are partly simplified representations with partly different scales. Embodiment of the invention

[0020] The Figure 1 The electrohydraulic power brake system 1 shown is intended for passenger cars with four wheel brakes 2. It has a brake unit 3 to which the four wheel brakes 2 are connected via brake lines. The vehicle brake system 1 is designed as a dual-circuit brake system, with two wheel brakes 2 connected to each brake circuit.

[0021] For externally powered braking, the brake system 3 has a piston-cylinder unit 4, whose piston 5 can be displaced in a cylinder 8 by an electric motor 6 via a screw drive 7 as a rotation / translation converter gear. The electric motor 6, the screw drive 7, and the piston-cylinder unit 4 form an externally powered brake pressure generator 9 of the brake unit 3 for generating brake pressure for externally powered braking. Externally powered braking, for which brake pressure is generated by the externally powered brake pressure generator 9, is the usual and intended brake application, i.e., service braking.

[0022] The external brake pressure generator 9, i.e. the cylinder 8 of the piston-cylinder unit 4 of the external brake pressure generator 9, is connected to a chamber 11‴ of a brake fluid reservoir 11 via a check valve 10, and the wheel brakes 2 are connected to the cylinder 8 of the piston-cylinder unit 4 of the external brake pressure generator 9 via a service brake valve 12 in each brake circuit, which are hydraulically connected in parallel.

[0023] The braking system 1 has an inlet valve 13 and an outlet valve 14 for each wheel brake 2, with which the wheel brake pressures in each wheel brake 2 can be individually regulated. This allows the wheel brake pressures in the wheel brakes 2 and thus the braking forces of the wheel brakes 2 to be regulated during normal driving operation 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. In each brake circuit, two inlet valves 13 are hydraulically connected in parallel to the external brake pressure generator 9 via a service brake valve 12.

[0024] In addition to the external brake pressure generator 9, the braking system 1 has a muscle-power-operated dual-circuit master brake cylinder 15, to which the wheel brakes 2 in each brake circuit are connected via a separating valve 16 and two inlet valves 13. The master brake cylinder 15 serves as a setpoint transmitter for the wheel brake pressures to be set in the wheel brakes 2. During external brake application, the brake pressure is generated by the external brake pressure generator 9. During external brake application, the master brake cylinder 15 is hydraulically separated from the wheel brakes 2 by closing the separating valves 16. If the external brake pressure generator 9 fails, the brake pressure is generated by actuating the master brake cylinder 15 using muscle power (so-called auxiliary braking).

[0025] To displace brake fluid from the master brake cylinder 15 when the isolation valves 16 are closed and to move the piston of the master brake cylinder 15 and a brake pedal 17, the brake unit 3 has a pedal travel simulator 18, which is connected to the master brake cylinder 15 in a brake circuit via a simulator valve 19. The pedal travel simulator 18 is a piston-cylinder unit with a spring-loaded piston.

[0026] In the described and illustrated embodiment of the invention, the inlet valves 13 and the isolating valves 16 are open 2 / 2-way solenoid valves in their de-energized basic positions and the service brake valves 12 of the external brake pressure generator 9, the outlet valves 14 and the simulator valve 19 are closed 2 / 2-way solenoid valves in their de-energized basic positions.

[0027] The hydraulic components of the electro-hydraulic power brake system 1, namely the valves 12, 13, 14, 16, 19, 21 of the power brake pressure generator 9, the master brake cylinder 15, the pedal travel simulator 18 and other components such as pressure sensors, are arranged in receptacles of a hydraulic block 20 of the brake unit 3 and are connected by a bore in the hydraulic block 20 in accordance with the Figure 1 shown hydraulic circuit diagram of the vehicle brake system 1. A receptacle 21' for the test valve 21 communicates with the master brake cylinder bore 15' ( Figure 3b ). The groove 38 and the hole 42 leading into it are in Figure 3b Drawn offset from the section plane. In fact, when viewed from the mounting side 29 of the hydraulic block 20, they are located behind the bore 42 and the inclined bore 39.

[0028] In addition, an oblique bore 39 leads from the base of the receptacle 21' for the test valve 21 to a horizontal bore 40, which runs parallel to the master brake cylinder bore 15' between the master brake cylinder bore 15' and the valve side to the first return line 22, whereby the receptacle 21' for the test valve 21 is connected to one of the connections 27' for the brake fluid reservoir 11 ( Figure 3b ).

[0029] In one of the two brake circuits, the master brake cylinder 15 is connected to one of the chambers 11' of the brake fluid reservoir 11 via a test valve 21. 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. In the other brake circuit, the master brake cylinder 15 is connected to a rear side of the pedal travel simulator 19, which in turn is connected to a chamber 11" of the brake fluid reservoir 11 and is therefore depressurized. The rear side of the pedal travel simulator 19 is one of two chambers of the cylinder of the pedal travel simulator 19, into which the piston of the pedal travel simulator 19 divides the cylinder of the pedal travel simulator 19. A front side of the pedal travel simulator 19 is connected to the master brake cylinder 15 via the simulator valve 19 and is pressurized by the master brake cylinder 15 when the simulator valve 19 is open.

[0030] In one brake circuit, the outlet valves 14 are connected to a chamber 11' of the brake fluid reservoir 11 by a first return line 22, which runs around the piston 5 of the piston-cylinder unit 4 in the cylinder 8 of the piston-cylinder unit 4 of the external brake pressure generator 9. In the other brake circuit, the outlet valves 14 are connected to another chamber 11" of the brake fluid reservoir 11 by a second return line 23, together with the master brake cylinder 15.

[0031] Figure 2 shows an engine side 24 and Figure 3a valve side 25 of the hydraulic block 20 of the brake unit 3. In the exemplary embodiment, the hydraulic block 20 is a flat, cuboid-shaped metal block that serves for the mechanical attachment and hydraulic connection of the hydraulic components of the power brake system 1. Equipped with the hydraulic components, the hydraulic block 20 forms the brake unit 3 of the vehicle brake system 1. "Flat" means that the hydraulic block 20 is approximately three to four times as wide or long as it is thick. Two opposite large sides of the hydraulic block 20 are almost square in the exemplary embodiment and form the motor side 24 and valve side 25. Figure 2 and 3 the hydraulic block 20 is shown unequipped, i.e. without the hydraulic components.

[0032] A narrow side of the hydraulic block 20, referred to here as the top side 26, has three cylindrical blind holes as connections 27', 27", 27‴ for the chambers 11', 11", 11‴ of the brake fluid reservoir 11, which is arranged on the top side 26 of the hydraulic block 20 (not shown). Connection nipples on a bottom of the brake fluid reservoir 11 enter the blind holes of the hydraulic block 20 forming the connections 27', 27", 27‴ and are sealed there with O-rings.

[0033] In the hydraulic block 20, a master cylinder bore 15', which forms the master cylinder 15, is arranged parallel to the top side 26 and in a center between the motor side 24 and the valve side 25. In Figure 2 and 3The master brake cylinder bore 15' is shown in dashed lines. In the exemplary embodiment, it is located slightly below a center of the hydraulic block 20 between the top side 26 and an opposite bottom side 28 of the hydraulic block 20, so that the master brake cylinder bore 15' lies approximately tangentially on a center plane of the hydraulic block 20 between the top side 26 and the bottom side 28.

[0034] The master brake cylinder bore 15' is open on a narrow side of the hydraulic block 20; it opens onto this narrow side of the hydraulic block 20 or has an opening there. The narrow side of the hydraulic block 20, where the master brake cylinder bore 15' is open or opens, is referred to here as the mounting side 29 of the hydraulic block 20. It borders the top side 26, the motor side 24, the valve side 25, and the bottom side 28 of the hydraulic block 20 and is intended for fastening the hydraulic block 20 to a firewall (not shown) of the motor vehicle. The hydraulic block 20 is attached to the firewall of the motor vehicle such that the top side 26 with the brake fluid reservoir 11 is at the top.The master brake cylinder bore 15' is open on the mounting side 29 of the hydraulic block 20, so that a master brake cylinder piston can be displaced in the master brake cylinder bore 15' by means of the foot brake pedal 17, which is attached to an opposite side of the bulkhead, via a pedal rod that pivotally connects the master brake cylinder piston to the foot brake pedal 17. The foot brake pedal 17 and the pedal rod are in . Figure 2 and 3 not drawn.

[0035] An external power cylinder bore 8', which forms the cylinder 8 of the external power brake pressure generator 9, is mounted perpendicular to the master brake cylinder bore 15' in the motor side 24 of the hydraulic block 20 and protrudes on the valve side 25 as a type of dome 30. The external power cylinder bore 8' is located slightly above the master brake cylinder bore 15', i.e., between the master brake cylinder bore 15' and the top side 26 of the hydraulic block 20. The external power cylinder bore 8' passes at a slight distance at right angles to the master brake cylinder bore 15'. It is arranged slightly off-center, offset toward the mounting side 29 of the hydraulic block 20.

[0036] The electric motor 6 of the external brake pressure generator 9, which is Figure 2not shown, is arranged coaxially to the external power cylinder bore 8' on the outside of the motor side 24 of the hydraulic block 20. A planetary gear as a reduction gear and the screw drive 7, which in the exemplary embodiment is a ball screw drive, are arranged coaxially to the external power cylinder bore 8' between the electric motor 6 and the piston 5 of the external power brake pressure generator 9 (in Figure 2 not drawn)

[0037] A cylinder bore 18' of the pedal travel simulator 18 is arranged in the valve side 25 of the hydraulic block 20, parallel to the power cylinder bore 8' and perpendicular to the master brake cylinder bore 15'. In the exemplary embodiment, the cylinder bore 18' is located between the master brake cylinder bore 15' and the top side 26 of the hydraulic block 20, closer to the top side 26 than to the master brake cylinder bore 15', and between the power cylinder bore 8' and a narrow side 31 of the hydraulic block 20 opposite the mounting side 29.

[0038] Receptacles 12', 13', 14', 16', 19', 21' for the solenoid valves 12, 13, 14, 16, 19, 21 and receptacles for other components such as pressure sensors are mounted in the valve side 25 of the hydraulic block 20. The receptacles, which are located in Figure 3The holes, designated with the reference number of the respective solenoid valve 12, 13, 14, 16, 19, 21 or other component, are cylindrical, partially diameter-stepped countersunk holes or blind holes in the hydraulic block 20. 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, 16, 19, 21, 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 25 of the hydraulic block 20.

[0039] The hydraulic block 20 of the brake unit 3 is designed according to the Figure 1The term "drilled" refers to the cylinder bores, receptacles for the solenoid valves, and connections in the hydraulic block 20, as well as the bores connecting them and forming the lines according to the hydraulic circuit diagram. The hydraulic block 20 is drilled in a Cartesian manner, meaning that the bores, receptacles, connections, lines, etc., are arranged parallel and perpendicular to each other and to the sides and edges of the hydraulic block 20. This does not exclude individual, diagonally running lines and bores.

[0040] Two connections 2' for brake lines leading to two wheel brakes 2 are located along the narrow side 31 opposite the mounting side 29 in the motor side 24, and two connections 2' for brake lines leading to two wheel brakes 2 are located near the underside 28 of the hydraulic block 20 in the motor side 24. "Near" means a distance of no more than one radius of the respective connection.

[0041] Between the power cylinder bore 8' and the top side 26, three through holes extending from the motor side 24 to the valve side 25 are provided as motor connection bores 32 for a power supply of the electric motor 6 of the power brake pressure generator 9 in the hydraulic block 20. The motor connection bores 32 are arranged on an imaginary arc around the power cylinder bore 8' between the power cylinder bore 8' and the top side 26 in the hydraulic block 20. Also arranged on the imaginary arc on which the motor connection bores 32 are arranged is a signal bore 33 for control lines and / or signal lines to or from the electric motor 6 in the hydraulic block 20.

[0042] The first return line 22, which is designed as a bore in the hydraulic block 20 and connects two of the receptacles 14' for the outlet valves 14 of two wheel brakes 2 around the piston 5 of the piston-cylinder unit 4 of the external brake pressure generator 9 with one of the connections 27' for one of the chambers 11' of the brake fluid reservoir 11, is in Figure 3shown with dashed lines. Starting from the connection 27' for the chamber 11' of the brake fluid reservoir 11, the first return line 22 initially leads as an oblique bore from a base of the connection 27' to the external power cylinder bore 8', which forms the cylinder 8 of the piston-cylinder unit 4 of the external power brake pressure generator 9. From the external power cylinder bore 8', the first return line 22 runs parallel in the direction of the fastening side 29, offset further downwards between the two receptacles 14' for the two outlet valves 14 to the underside 28 of the hydraulic block 20. The two receptacles 14' are connected to the first return line 22 by transverse bores which open at the fastening side 29 of the hydraulic block 20 (not shown)."Oblique bore" means that the section of the first return line 22 leads from the connection 27' for the brake fluid reservoir 11 obliquely to the motor side 24 and the valve side 25 and - in the exemplary embodiment parallel to the fastening side 29 and the narrow side 31 - to the external power cylinder bore 8'. Except for the section from the connection 27' to the power cylinder bore 8', the first return line 22, like all other bores, runs parallel to the sides 24, 25, 26, 28, 29, 31 and edges of the hydraulic block 20. The section of the first return line 22 that comes from the connection 27' for the brake fluid reservoir 11 and also the section of the first return line 22 that leads to the receptacles 14' for the outlet valves 14, open into a groove 34 in the power cylinder bore 8', which is located in a radial plane of the power cylinder bore 8', in which the piston 5 of the piston-cylinder unit 4 of the power brake pressure generator 9 is located when it is installed.In this way, the first return line 22 is routed around the piston 5 of the piston-cylinder unit 4 of the external brake pressure generator 9 without communicating with the cylinder 8 of the piston-cylinder unit 4 of the external brake pressure generator 9. The groove 34 in the external cylinder bore 8' is in . Figure 3 drawn with dashed lines.

[0043] The second return line 23 is also marked with dashed lines in Figure 3 shown. It leads from the two other receptacles 14' for the outlet valves 14 of two wheel brakes 2 upwards to the cylinder bore 18' of the pedal travel simulator 18 and from there, parallel in the direction of the narrow side 31 of the hydraulic block 20, offset further upwards to a different connection 27" of a chamber 11" of the brake fluid reservoir 11 than the first return line 22.

[0044] Between the cylinder bore 18' of the pedal travel simulator 18 and the connection 27" of the chamber 11" of the brake fluid reservoir 11, the second return line 23 runs parallel to the fastening side 28 and to the opposite narrow side 31 of the hydraulic block 20, but obliquely to the motor side 24 and the valve side 25 of the hydraulic block 20. The oblique course of the second return line 23 is in Figure 3a The cutting plane of the Figure 3a has an offset radially to the cylinder bore 18' of the pedal travel simulator 18 in the direction of the fastening side 29 or in the direction of the narrow side 31 of the hydraulic block 20 opposite the fastening side 29. The offset of the cutting plane of the Figure 3a is in Figure 3with the section line AA. The section of the second return line 23 running between the cylinder bore 18' of the pedal travel simulator 18 and the connection 27" of the chamber 11" of the brake fluid reservoir 11 at an angle to the motor side 24 and the valve side 25 of the hydraulic block 20 is Figure 3a drawn offset in the section plane. In fact, the oblique section of the second return line 23 has a radial offset to the connection 27" of the chamber 11" of the brake fluid reservoir 11, which Figure 3 can be seen.

[0045] A transverse bore 37 connects the two receptacles 14' for the exhaust valves 14.

[0046] The second return line 23 opens into the master brake cylinder bore 15', so that one of the chambers of the dual-circuit master brake cylinder 15 is also connected to one of the chambers 11" of the brake fluid reservoir 11 through the cylinder bore 18' of the pedal travel simulator 18. The second return line 23 opens into a radial plane of the cylinder bore 18' of the pedal travel simulator 18, which is located on a rear side of the piston of the pedal travel simulator 18 and which is depressurized due to its connection to the brake fluid reservoir 11.

[0047] The second return line 23 is drilled into the hydraulic block 20 from the underside 28 and radially penetrates the master brake cylinder bore 15' so that a drill bit, when drilling the second return line 23, encounters a cylinder wall of the master brake cylinder bore 15' perpendicularly and not at an angle upon exiting the master brake cylinder bore 15'. As a result, the drill bit does not experience any offset tangential to the master brake cylinder bore 15' upon exiting the master brake cylinder bore 15' and does not break off. The master brake cylinder bore 15' has a circumferential groove 41 into which the second return line 23 opens radially at two diametrically opposite points.

[0048] Figure 4shows a fragment of the hydraulic block 20 with a view of the narrow side 31 opposite the fastening side 29. The dome 30, which extends the power cylinder bore 8' and protrudes from the valve side 25 of the hydraulic block 20, can be seen. The power cylinder bore 8', as well as the connections 27", 27‴ of the brake fluid reservoir 11, are shown in solid lines. A brake line designed as a bore in the hydraulic block 20, which opens coaxially into one of the connections 27‴, runs, after an angled section, parallel to the power cylinder bore 8' in a wall of the dome 30 outside the power cylinder bore 8' and opens into a circumferential groove 36, which encloses the power cylinder bore 8' in the dome 30.

[0049] The connection 27‴ for the brake fluid reservoir 11 has a recess 10' extending it as a receptacle for the check valve 10 in the brake line 35 leading to the power cylinder bore 8'. The check valve 10 is in Figure 4 represented as a circuit symbol.

[0050] In order to vent the master brake cylinder 15, i.e. to remove air bubbles from the brake fluid in the master brake cylinder 15, a brake line 43, which connects the master brake cylinder bore 15' with one of the receptacles 16' for the two isolating valves 16, opens tangentially into the master brake cylinder bore 15' at a circumferential point facing the upper side 26 of the hydraulic block 20 ( Figure 3b ). In Figure 3 On the right, near the mouth of the external power cylinder bore 15' on the fastening side 29 of the hydraulic block 20, the arrangement of one of the receptacles 16' for a separating valve 16 can be seen, tangential to the top side 26 of the hydraulic block 20.

Claims

1. Hydraulic block for a brake assembly of a hydraulic external-force brake installation for a motor vehicle, wherein the hydraulic block (20) has a top side (26), which is intended for mounting of a brake fluid vessel (11) and has connections (27', 27", 27‴) for the brake fluid vessel (11), a fastening side (29), which adjoins the top side (26) and is configured for fastening of the hydraulic block (20) to a bulkhead of the motor vehicle and at which a master brake cylinder bore (15') opens out, a motor side (24), which adjoins the top side (26) and the fastening side (29) and at which an external-force cylinder bore (8') opens out and on which there is able to be arranged an electric motor (6) for displacement of an external-force piston (5) of an external-force brake pressure generator (9) in the external-force cylinder bore (8'), connections (2') for hydraulic wheel brakes (2) and a simulator cylinder bore (18') for a pedal travel simulator (18) of the external-force brake installation (1), characterized in that the external-force cylinder bore (8') and the simulator cylinder bore (18') are provided in the hydraulic block (20) between the top side (26) and the master brake cylinder bore (15'), and in that a second return line (23) leads in the hydraulic block (20) from a receptacle (14') for an outlet valve (14) through the simulator cylinder bore (18') to one of the connections (27") for the brake fluid vessel (11).

2. Hydraulic block according to Claim 1, characterized in that the second return line (23) leads from the receptacle (14') for the outlet valve (14) to the master brake cylinder bore (15'), and from the simulator cylinder bore (18') to the connection (27") for the brake fluid vessel (11) at an angle to the motor side (24).

3. Hydraulic block according to Claim 1 or 2, characterized in that the second return line (23) radially extends through the master brake cylinder bore (15').

4. Hydraulic block according to one or more of Claims 1 to 3, characterized in that a first return line (22) leads in the hydraulic block (20) from a receptacle (14') for an outlet valve (14) to the external-force cylinder bore (8') and from the external-force cylinder bore (8') to one of the connections (27') for the brake fluid vessel (11).

5. Hydraulic block according to Claim 4, characterized in that a portion of the first return line (22) coming from the receptacle (14') for the outlet valve (14) opens out into a groove (34) in the external-force cylinder bore (8') at a different circumferential point than a portion of the first return line (22) leading to the connection (27').

6. Hydraulic block according to one or more of the preceding claims, characterized in that the hydraulic block (20) has a dome (30) which protrudes from a valve side (25) situated opposite the motor side (24) and into which the external-force cylinder bore (8') extends, and in that a portion of a brake line (35) leading in the hydraulic block (20) from one of the connections (27‴) for the brake fluid vessel (11) in the top side (26) of the hydraulic block (20) to the external-force cylinder bore (8') runs through a cylinder wall of the dome (30).

7. Hydraulic block according to one or more of the preceding claims, characterized in that the hydraulic block (20) has receptacles (12', 13', 14', 16', 19') for valves (12, 13, 14, 16, 19) of a brake pressure control system of the external-force brake installation (1) in a valve side (25), situated opposite the motor side (24), of the hydraulic block (20).

8. Hydraulic block according to one or more of the preceding claims, characterized in that the connections (2') for the wheel brakes (2) are arranged in the motor side (24) of the hydraulic block (20).

9. Hydraulic block according to one or more of the preceding claims, characterized in that a brake line (43) leading in the hydraulic block (20) from the master brake cylinder bore (15') to a receptacle (16') for an isolation valve (16) opens out into the master brake cylinder bore (15') at a circumferential point which is directed towards the top side (26) of the hydraulic block (20).

10. Hydraulic block according to one or more of the preceding claims, characterized in that one of the connections (27‴) for the brake fluid vessel (11) in the top side (26) of the hydraulic block (20) has a concentric receptacle (10') for a check valve (10), from which a brake line (35) leads in the hydraulic block (20) to the external-force cylinder bore (8').

11. Hydraulic block according to one or more of the preceding claims, characterized in that motor connection bores (32) for supply of power to the electric motor (6) of the external-force brake pressure generator (9) and a signal bore (33) for control lines and / or signal lines to or from the electric motor (6) are provided in the hydraulic block (20) on an imaginary arc around the external-force cylinder bore (8') such that they extend through the hydraulic block (20) from the motor side (24) to the valve side (25).