Hydraulic block for hydraulic assembly of hydraulic vehicle brake system

Abstract

The present invention proposes that an external force piston (5) is radially guided only in an axially limited guide section (6) in an external force cylinder bore (4) of a hydraulic block (2) of a hydraulic assembly (1) of a hydraulic external force vehicle brake system, and the external force cylinder bore (4) is configured with a larger diameter axially outside the guide section (6). A brake fluid channel (11) passes through the guide section (6) to the mouth of a brake fluid line (15).

Description

Technical Field

[0001] The invention relates to a hydraulic block for a hydraulic assembly of a hydraulic vehicle brake system. Background Art

[0002] International Patent Application WO 2013 / 023 953A1 discloses a hydraulic assembly for a slip-controlled, hydraulically operated vehicle brake system. The hydraulic assembly comprises a hydraulic block having a master brake cylinder bore mounted therein, in which a master brake cylinder piston is axially displaceably accommodated for muscle-operated vehicle brake system operation. The master brake cylinder piston is movable within the master brake cylinder bore by a pedal rod that is articulatedly connected to the master brake cylinder piston and to a foot brake pedal. To operate the vehicle brake system by external force, the hydraulic block comprises an external force cylinder bore, in which the external force piston can be displaced by an electric motor via a screw drive mechanism. Summary of the Invention

[0003] The hydraulic block according to the present invention is provided for a hydraulic assembly of a hydraulic, especially slip-controlled, externally-powered vehicle brake system. Slip control is particularly effective for anti-lock braking, drive slip, and / or vehicle dynamics control / electronic stability program, for which the abbreviations ABS, ASR, and / or FDR / ESP are often used. The latter is also colloquially referred to as "anti-slip control." Slip control is well known and will not be explained in detail here.

[0004] The hydraulic block is used to mechanically secure and hydraulically connect the hydraulic components of the vehicle brake system or its brake pressure control and / or slip control system. These hydraulic components include, in particular, solenoid valves, check valves, hydraulic accumulators, damper chambers, and pressure sensors. The hydraulic components are secured in receptacles within the hydraulic block, which are typically designed as cylindrical through-holes or blind holes, sometimes with a diameter step. "Connected" means that the receptacles or the hydraulic components secured therein are connected via lines within the hydraulic block according to the hydraulic circuit diagram of the vehicle brake system or its slip control system. These lines are typically drilled into the hydraulic block.

[0005] The hydraulic block is equipped with hydraulic components of the vehicle brake system or its slip control system to form a hydraulic assembly, where "equipped" means that the hydraulic components are fixed in the respective receptacles of the hydraulic block.

[0006] The hydraulic wheel brakes of the vehicle brake system are connected to the hydraulic block via brake lines.

[0007] In order to externally operate the vehicle brake system, the hydraulic block according to the present invention has an external force cylinder bore in which an external force piston is accommodated axially displaceably. The external force cylinder bore is often also called a plunger cylinder, and the external force piston is called a plunger piston. To generate brake pressure, the external force piston can be moved in the external force cylinder bore using an external force drive device, which has, for example, an electric motor and a screw transmission mechanism. In order to guide the external force piston axially displaceably, the external force cylinder bore has a guide section that extends over a portion of the axial length of the external force cylinder bore and guides the external force piston radially. In particular, the external force cylinder bore has the same diameter as the external force piston in the guide section. In the guide section, the external force cylinder bore can also have a slightly larger diameter than the external force piston, which is necessary so that the external force piston can move axially without clamping. Outside the guide section, the external force cylinder bore has a larger diameter so that the external force piston preferably does not rest against the circumference of the external force cylinder bore.

[0008] The external force piston is sealed in the external force cylinder bore by a piston seal, in particular a sealing ring. According to the present invention, the guide section of the external force cylinder bore for the external force piston is located on the pressure side of the piston seal. The pressure side is the side on which the external force piston generates the brake pressure for operating the vehicle brake system when it moves in the external force cylinder bore. Therefore, the guide section extends from the piston seal into the working chamber of the external force cylinder bore, the external force piston limiting this working chamber on one side, and reducing the volume of this working chamber when the external force piston moves for brake operation in order to squeeze the brake fluid out of the working chamber in the direction of the hydraulic wheel brake. The guide section of the external force cylinder bore for the external force piston can end at the piston seal or extend beyond the piston seal on the side opposite to the pressure side, for example to a second piston seal.

[0009] According to the present invention, the hydraulic block has a brake fluid channel in the circumference of the external force cylinder bore in the guide section on the pressure side of the external force piston, and the brake fluid channel reaches the piston seal. The brake fluid channel is, for example, a groove or slot in the guide section of the external force cylinder bore and can extend, for example, parallel to the axis or in a spiral shape. Through the brake fluid channel, the brake fluid reaches the piston seal from the working chamber of the external force cylinder bore in order to lubricate the piston seal. Through the brake fluid channel, the working chamber of the external force cylinder bore is connected to a brake fluid line, which flows into the external force cylinder bore within the guide section. Through the brake fluid line, the working chamber of the external force cylinder bore is connected, for example, to a brake fluid reservoir and / or to a wheel brake.

[0010] In this case, what are referred to as “drillings” or holes in the hydraulic block, for example the external force cylinder bore or the master brake cylinder bore, can also be produced other than by drilling.

[0011] Preferred and further exemplary embodiments relate to developments and advantageous configurations of the invention given in the main exemplary embodiment.

[0012] All features disclosed in the description and drawings can be implemented in embodiments of the invention individually or in any combination in principle. In principle, embodiments of the invention that do not have all features of the main embodiment or embodiments of the invention but only have one or more features are possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention is explained in more detail below with reference to the embodiments shown in the drawings. The single drawing shows a section through the external force cylinder bore of a hydraulic block according to the invention in an axial direction. DETAILED DESCRIPTION

[0014] Figure 1 The hydraulic assembly 1 according to the invention shown in FIG is provided for generating brake pressure in a hydraulic, externally-powered vehicle brake system with slip control. Such slip control systems are, for example, anti-lock braking systems, drive slip systems, and / or vehicle dynamics control systems / electronic stability programs, for which the abbreviations ABS, ASR, FDR / ESP are often used.

[0015] The hydraulic assembly 1 according to the present invention includes a hydraulic block 2, which serves to mechanically secure and hydraulically connect hydraulic and other components of the slip control system, such as solenoid valves, check valves, hydraulic reservoirs, and damper chambers. These components are arranged on and in the hydraulic block 1 and hydraulically interconnected via boreholes (not shown) in the hydraulic block 2, according to the hydraulic circuit diagram of the externally powered vehicle brake system and the slip control system. Two solenoid valves 27 are shown as exemplary switching symbols.

[0016] In the embodiment of the invention shown and described, the hydraulic block 2 is a cuboid flat metal block, for example made of an aluminum alloy, which is provided with bores for accommodating components of the slip control unit and is drilled according to the hydraulic circuit diagram of the vehicle brake system and the slip control unit.

[0017] The hydraulic block 2 has an external force cylinder bore 4, in which an external force piston 5 is accommodated axially displaceably. The external force cylinder bore 4 extends transversely through the hydraulic block 2 and is open at one end. At the other, closed end on the opposite side of the hydraulic block 2, the hydraulic block 2 has an outwardly protruding, cylindrical, cup-shaped formation 7 integral with the hydraulic block 2 and coaxial with the external force cylinder bore 4. This formation axially extends the external force cylinder bore 4. To guide the external force piston 5 axially displaceably, the external force cylinder bore 4 has a guide section 6 that extends axially over a portion of the length of the external force cylinder bore 4 and radially guides the external force piston 5 in the external force cylinder bore 4. In the guide section 6, the external force cylinder bore 4 has the same diameter as the external force piston 5. In the guide section 6, the diameter of the external force cylinder bore 4 can also be slightly larger so that the external force piston 5 has clearance and can move axially without being clamped. Axially outside the guide section 6 on both sides, the external-force cylinder bore 4 has a larger diameter than the external-force piston 5 , so that an annular gap 8 is present which surrounds the external-force piston 5 .

[0018] In the guide section 6, the external force cylinder bore 4 has two axially spaced, circumferential sealing grooves, in which piston seals 9 and 10 are respectively arranged, which seal between the external force cylinder bore 4 and the external force piston 5. The piston seal 9 facing the shaped portion 7 can also be understood as a high-pressure seal 9, and the piston seal 10 facing the open end of the external force cylinder bore 4 can be understood as a low-pressure seal 10. The two piston seals 9 and 10 are sealing rings made of elastomer or other elastically deformable plastic or other materials. The piston seals 9 and 10 are composed solely of elastomer and do not have support rings, support tabs or other support elements or the like made of metal or, for example, deformation-resistant plastic. In this embodiment, the two piston seals 9 and 10 are lip seals having a sealing lip that surrounds the inside and seals against the outer circumference of the external force piston 5.

[0019] In the direction of the open end of the external-force cylinder bore 4, the guide section 6 ends at the low-pressure seal 10 or preferably continues axially on the low-pressure seal 10 in a short section not exceeding one or a few millimeters. In the direction of the shaped portion 7, the guide section 6 continues in the shaped portion 7 for approximately half the distance between the external-force piston 5 in its retracted initial position shown and the closed end of the external-force cylinder bore 4. The retracted initial position of the external-force piston 5 is its position farthest from the closed end of the external-force cylinder bore 4 during operation. The side of the external-force piston 5 and the high-pressure seal 9 facing the closed end is their pressure side because, when the external-force piston 5 moves into the shaped portion 7, it generates braking pressure in the shaped portion 7 and, therefore, in the external-force cylinder bore 4.

[0020] On the pressure side of the external force piston 5 or the high-pressure seal 9, the guide section 6 has a groove serving as a brake fluid channel 11, which reaches the external force piston 5 in the retracted initial position or the high-pressure seal 9. The brake fluid channel 11 can extend axis-parallel, as shown in the figures, or, for example, in a spiral shape (not shown). A plurality of brake fluid channels 11 can be provided distributed around the circumference (not shown).

[0021] Between the two piston seals 9 and 10, the external force cylinder bore 4 has a circumferential groove 12, into which a brake fluid line 13 opens. The brake fluid line leads to a brake fluid reservoir (not shown) mounted on the hydraulic block 2. Brake fluid for lubricating the external force piston 5 and the piston seals 9 and 10 reaches the circumference of the external force piston 5 via the brake fluid line 13 and the groove 12. When the external force piston 5 moves axially in the external force cylinder bore 4, the brake fluid is distributed in the axial direction, thereby lubricating the external force piston 5 and the piston seals 9 and 10 in the guide section 6 of the external force cylinder bore 4.

[0022] Directly at the pressure-side end of the external-force piston 5 in the retracted initial position, the external-force cylinder bore 4 has another circumferential groove 14 that extends over a limited circumferential section and into which a brake fluid line 15 also flows. Through this brake fluid line, a hydraulic wheel brake (not shown) (which is connected to the hydraulic block 2 via a brake line) is connected to the external-force cylinder bore 4 via a solenoid valve 3. By moving the external-force piston 5 toward the closed end, a brake pressure for actuating the wheel brake can be generated in the external-force cylinder bore 4. The groove 14 and the brake fluid line 15 flowing therein are also connected to the external-force cylinder bore 4 between the external-force piston 5 and the closed end of the external-force cylinder bore 4 during displacement of the external-force piston 5, via a brake fluid channel 11 that extends through the guide section 6 of the external-force cylinder bore 4 to the groove 14. This is because the brake fluid channel 11 extends to the larger diameter portion of the external-force cylinder bore 4 between the guide section 6 and the closed end of the external-force cylinder bore 4.

[0023] like Figure 1 As can be seen, the high-pressure seal 9 also seals against the external-force piston 5 in its retracted initial position, and there is no displacement position of the external-force piston 5 in which the high-pressure seal 9 does not seal against the external-force piston 5. This avoids dead travel, as the external-force piston 5, when displacing in the external-force cylinder bore 4, squeezes the brake fluid out of the external-force cylinder bore 4 from its retracted initial position right from the start.

[0024] To move the external force piston 5 in the external force cylinder bore 4 to generate external force braking pressure, the hydraulic assembly 1 includes an electric motor 16. This electric motor moves the external force piston 5 in the external force cylinder bore 4 via a planetary gear mechanism 17 and a ball screw mechanism 18, which serve as a reduction gear mechanism. The ball screw mechanism 18 can also be generally understood as a screw mechanism or a rotation / translation conversion mechanism. The ball screw mechanism 18 is partially arranged in the external force piston 5, coaxially with the external force cylinder bore 4, and the external force piston is designed as a hollow piston for this purpose. The ball screw mechanism 18 is rotatably supported by a ball bearing 19, which is arranged on the outside of the hydraulic block 2 using a tubular bearing holder 20. The planetary gear mechanism 17 is also arranged coaxially with the external force cylinder bore 4 and the external force piston 5, between the ball screw mechanism 18 and the electric motor 16. The electric motor 16 has a motor housing 21, which is also screwed onto the hydraulic block 2 externally, coaxially with the external force cylinder bore 4 and the external force piston 5. The electric motor 16, the planetary gear mechanism 17, and the ball screw mechanism 18 form an electromechanical external force drive 22, which enables the external force piston 5 to be axially displaced in the external force cylinder bore 4 by external force to generate brake pressure for the vehicle brake system. Together with the external force cylinder bore 4 and the external force piston 5, the external force drive 23 forms the external force brake pressure generator 23 of the hydraulic assembly 1 according to the present invention. The present invention does not exclude the possibility of generating brake pressure using external force in a manner other than electromechanical.

[0025] In the illustrated and described embodiment of the present invention, hydraulic block 2 has a master brake cylinder bore 24, in which a master brake cylinder piston (not shown) can be arranged. This master brake cylinder piston is mechanically displaced in master brake cylinder bore 24 via a piston rod having a foot brake pedal or hand brake lever (not shown). Furthermore, hydraulic block 2 has a simulator cylinder bore 26 for a simulator piston (not shown), for example, a spring-loaded one. Brake fluid can be displaced from master brake cylinder bore 24 into simulator cylinder bore 25 to displace the master brake cylinder piston in master brake cylinder bore 24 when the vehicle brake system is actuated by external force. In addition to using external brake pressure generator 23, the vehicle brake system can also be actuated by muscle force by displacing the master brake cylinder piston in master brake cylinder bore 24. This is particularly useful in the event of a malfunction or failure of external brake pressure generator 23.

[0026] The external force cylinder bore 4 , the master brake cylinder bore 24 and / or the simulator cylinder bore 25 can also be produced in a manner other than drilling.

[0027] The external force cylinder bore 4 or the external force brake pressure generator 23 is connected to the hydraulic wheel brakes via one or two isolating valves 26 connected hydraulically in parallel and an inlet valve (not shown) connected hydraulically in series with the isolating valves 26. Furthermore, the external force cylinder bore 4 or the external force brake pressure generator 23 is connected to the master brake cylinder bore 24 or a brake fluid reservoir (not shown) via the isolating valves 26 and a suction valve 27 connected hydraulically in series with the isolating valves. A differential pressure valve 28 is integrated into at least one of the isolating valves 26, which limits the maximum pressure in the external force cylinder bore 4. This prevents inadmissibly high pressures in the external force cylinder bore 4, even if the brake fluid thermally expands in the external force cylinder bore 4, without displacement of the external force piston 5.

[0028] Isolating valve 26 and suction valve 27 are solenoid valves 3 of the slip control unit of the vehicle brake system, and are equipped with hydraulic block 2. Isolating valve 26 and suction valve 27 are 2 / 2-way solenoid valves, wherein isolating valve 26 is closed in its de-energized initial position, and suction valve 27 is open in its de-energized initial position. As previously mentioned, differential pressure valve 28 is integrated into at least one of the isolating valves 26.

Claims

1. A hydraulic block for a hydraulic assembly of a hydraulic external force vehicle brake device, wherein: The hydraulic block (2) has an external force cylinder hole (4), in which an external force piston (5) can be accommodated axially movably and is sealed by a piston seal, wherein the external force cylinder hole (4) has a guide section (6) on the pressure side of the piston seal, in which the external force cylinder hole radially guides the external force piston (5), and is characterized in that the hydraulic block (2) has a brake fluid channel (11) in the circumference of the external force cylinder hole (4), and the brake fluid channel passes through the external force piston (5) on the pressure side. The guide section (6) extends to the piston seal, and the brake fluid channel (11) extends to the larger diameter part of the external force cylinder hole (4) between the guide section (6) and the closed end of the external force cylinder hole (4). The guide section (6) of the external force cylinder hole (4) has a circumferential groove (14) on the pressure side of the external force piston (5) in the retracted initial position of the external force piston (5), and the brake fluid line (15) leads to the groove. The brake fluid channel (11) passes through the guide section (6) of the external force cylinder hole (4) to the groove (14).

2. The hydraulic block according to claim 1, characterized in that In a retracted initial position, the external force piston (5) rests sealingly against the piston seal.

3. The hydraulic block according to claim 1 or 2, characterized in that: The piston seal has a sealing ring which consists exclusively of elastic material and / or has no axial support of its own to counteract pressure loading in the axial direction.

4. The hydraulic block according to claim 1 or 2, characterized in that: The external force cylinder bore (4) has two piston seals, and the guide section (6) also extends between the two piston seals.

5. The hydraulic block according to claim 1 or 2, characterized in that: The guide section (6) of the external force cylinder bore (4) for the external force piston (5) extends only over a portion of the length of the external force cylinder bore (4) on the pressure side of the external force piston (5) and / or does not extend on the side of the piston seal facing away from the pressure side.

6. The hydraulic block according to claim 1 or 2, characterized in that: The external force cylinder bore (4) is connected to the master brake cylinder bore (24) and / or to a brake fluid reservoir in the hydraulic block (2) via a non-return valve or a pressure differential valve (28) and a controllable suction valve (27).

7. The hydraulic block according to claim 6, characterized in that The non-return valve or the differential pressure valve (28) is integrated into a controllable isolating valve (26), via which the wheel brake is connected to the external force cylinder bore (4).

8. The hydraulic block according to claim 1 or 2, characterized in that: The hydraulic block (2) has an external force driving device (22) for moving the external force piston (5) in the external force cylinder hole.

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