Hydraulic assembly for controlling the brake pressure of the wheel brakes of a motor vehicle

Abstract

The invention relates to a hydraulic assembly, in particular for controlling the brake pressure of wheel brakes of an electronically slip-controlled brake system of a motor vehicle. The known hydraulic assembly comprises a hydraulic block (10) with a receptacle (12, 14) for accommodating a pump element; a pipe connection (22) for contacting the hydraulic assembly with the wheel brake; a channel (20) for supplying the pump element with brake fluid; and a hydraulic cavity (28) formed inside the hydraulic block (10) and in contact with the receptacle (12, 14) for the pump element. The invention provides that the cavity (28) comprises a riser pipe (26) extending from the receptacle (12, 14) for the pump element to the pipe connection (22, 24) of the hydraulic block (10) and in contact with the receptacle (12, 14) for the pump element. Such an intake pipe (26) collects gases discharged from the pressure medium due to temperature changes and / or pressure changes and, for example, improves the operating noise of the hydraulic assembly.

Description

Technical Field

[0001] The invention relates to a hydraulic assembly, in particular to a hydraulic assembly for controlling the brake pressure of wheel brakes of an electronically slip-controlled brake system of a motor vehicle. Background Art

[0002] Electronically slip-controlled brake systems have a hydraulic assembly as a basic component, which adapts the brake pressure of the wheel brakes to the slip that occurs momentarily on the correspondingly assigned wheel. The brake fluid used for this purpose can dissolve a certain amount of gas depending on the temperature and pressure. If the brake fluid is subsequently subjected to isobaric heating, for example due to self-heating, solar radiation or engine heat, and / or isothermal pressure reduction, for example due to a periodic brake pressure reduction or possible cavitation, the dissolved gas will be released from the brake fluid again and cause bubbles to accumulate in the brake circuit. This behavior is influenced by various parameters, such as the water content or aging state of the brake fluid, temperature, pressure, brake fluid type and operating state of the brake system. Due to this behavior of the brake fluid during its service life, it is difficult to carry out a targeted design or performance prediction of the brake system. Similarly, there is no technical solution to keep the brake fluid in a specified state permanently.

[0003] Air bubbles in the brake circuit can influence the functional properties of the brake system, for example by dampening pressure pulsations on the suction or pressure side of a pressure generator that generates the brake pressure, but can also amplify vibrations of the hydraulic assembly or lead to undesirable operating noises at valves of the hydraulic assembly used to regulate the brake pressure.

[0004] However, in order to still meet the market requirements for functional properties, noise and performance of the brake system during its service life, components are installed in current brake systems that reduce the above-described disadvantages. Such components are, for example, flexible brake lines, elastic mounts for fixing the hydraulic assembly of the electronically slip-controlled brake system on the vehicle body, or pulsation dampers mounted on the hydraulic assembly.

[0005] Such devices take up installation space, lead to increased parts and assembly costs, make it difficult to predict the operating characteristics of the brake system during its service life, and ultimately make the design of the brake system more complicated. Summary of the invention

[0006] The invention relates to a hydraulic assembly, as is already known from the earlier patent application DE 10 2018 219 975. The hydraulic assembly accordingly comprises a hydraulic block with a receptacle for accommodating a pump element, a pipe connection for contacting the hydraulic assembly with the wheel brakes, a channel for supplying the pump element with brake fluid, and a hydraulic cavity formed within the hydraulic block and separated from the surroundings of the hydraulic assembly, which is at least indirectly in contact with the receptacle of the pump element.

[0007] The invention differs from this prior art in that the pipe connection for the wheel brakes is arranged in the region of the upper side of the hydraulic block and a standpipe surrounded by the hydraulic cavity extends from the receptacle of the pump element toward the pipe connection.

[0008] According to this feature, it is possible that, due to the effective gravity buoyancy, the gas bubbles generated in the brake system can accumulate in this cavity as if automatically, and thus effectively reduce the operating noise and pressure pulses generated by the pump element on the suction side of the pump element. The proposed measure can be implemented in a structurally neutral manner on the hydraulic block of the hydraulic assembly and does not cause any additional components and their assembly costs. The measure can be implemented in a structurally neutral manner during the production of the hydraulic block and can also be combined with known damping devices, or even make such additional damping devices unnecessary. Finally, the uniqueness of the present invention lies in that the hydraulic assembly is not affected by wear caused by aging and remains effective during the service life of the hydraulic assembly. The present invention can be used to estimate the operating characteristics of the hydraulic assembly during the service life in a balanced and overall more accurate manner, which in turn simplifies the design of the brake system.

[0009] Further advantages or advantageous developments of the invention will be found in the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Different exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

[0011] Figures 1 to 8 The drill patterns of hydraulic blocks of a hydraulic assembly of an electronically slip-controlled vehicle brake system designed according to the invention are each shown in a three-dimensional illustration. Figure 1 , Figure 5 , Figure 6 and Figure 8 Here the entire hydraulic block with two brake circuits is shown, while Figures 2 to 4 and Figure 7 Only half of the hydraulic block is shown, and thus only one of the brake circuits can be seen. Corresponding components are denoted by uniform reference numerals in the figures. DETAILED DESCRIPTION

[0012] according to Figure 1 The hydraulic block 10 shown is also often referred to as the pump housing of the hydraulic assembly. The hydraulic block is cuboid and has two outer sides parallel to each other on each spatial axis. A plurality of differently graded or differently sized receptacles are constructed on these outer sides of the hydraulic block 10. Each of these receptacles is open to one of the outer sides and ends in the shape of a blind hole inside the hydraulic block 10. The receptacles are used, for example, to accommodate: pump elements equipped with pistons for generating brake pressure, drive elements for actuating these pump pistons, valves for regulating the brake pressure generated by the pump elements, pressure medium reservoirs for buffering the brake fluid discharged from the wheel brakes when the brake pressure is reduced, or damping devices for suppressing the pulses of the brake fluid. For this purpose, these hydraulic components are inserted into the receptacles from the outside and fixed or supported therein. In addition, hydraulic connectors are also provided on the hydraulic block 10, through which the hydraulic block 10 can be contacted with the master brake cylinder and / or with the wheel brakes of the brake system by means of externally routed brake lines. The described receptacles and connections are connected to each other via pressure medium channels according to the ratio of the hydraulic circuit diagram known per se for electronically slip-controlled vehicle brake systems. For reasons of installation space and / or manufacturing technology, the receptacles and pressure medium channels are preferably arranged orthogonally to each other on the hydraulic block 10 .

[0013] exist Figure 1 1, two horizontally aligned receptacles 12, 14 can be seen, which extend from the left outer side or the right outer side into the interior of the hydraulic block 10 and whose inner ends open into a third receptacle 16 which is open toward the front of the hydraulic block 10. The two horizontal receptacles 12, 14 are each used to accommodate a pump element. For this purpose, the third receptacle 16 can accommodate a rotationally driven eccentric element which mechanically drives the pistons of the two pump elements which partially extend into the third receptacle 16 from the opposite side to perform a reciprocating linear motion.

[0014] Furthermore, two storage chambers 18 are provided below the two receptacles for pump elements in the hydraulic block 10 shown. The storage chambers 18 extend from the underside into the hydraulic block 10 and receive the pressure medium discharged from the wheel brakes in the event of a reduction in brake pressure. The storage chambers 18 are hydraulically connected to one of the receptacles 12, 14 for the pump elements via a vertical channel 20. The vertical channel 20 connects the storage chambers 18 to the suction side of the pump element inserted into the associated receptacle 12, 14 and thus ensures that the pump element is supplied with brake fluid.

[0015] Four pipe connections 22 are arranged next to each other on the upper side of the hydraulic block 10. These four pipe connections 22 are used to connect the hydraulic block 10 to the wheel brakes of the vehicle brake system via external pipes. Two other pipe connections 24 are located in the area of ​​the upper side of the front side of the hydraulic block 10. These two pipe connections 24 make the hydraulic block 10 in contact with the two brake circuits of the master brake cylinder via pipes.

[0016] It is foreseeable that the fully assembled hydraulic assembly is arranged on the vehicle body in its installed state so that the pipe connections 22, 24 are aligned upwards, i.e., are located in or in the area of ​​the upper side of the installed hydraulic assembly, because they enable mechanical contact of the hydraulic assembly with the described external components. Figure 1 Accordingly, the hydraulic block 10 is shown in its installed position.

[0017] It can be seen that the vertical channel 20 extends orthogonally to the receptacles 12, 14 of the pump element and, as described above, opens into the receptacles 12, 14 in the region of the suction side of the pump element. The region surrounding the opening corresponds to the region of lowest pressure within the brake circuit. As described above, this can lead to the gas released so far escaping from the brake fluid in this region and accumulating as bubbles.

[0018] In order to prevent any bubbles that have occurred from being sucked in by the pump element and conveyed further to the pump pressure side, the vertical channel 20 is extended or extended further on its side opposite the point of entry into the pump receptacle. A standpipe 26 is formed in the section of the vertical channel 20 that extends through the receptacles 12, 14 for the pump element, and preferably extends in a vertical spatial direction toward the pipe connections 22, 24 formed on the hydraulic block 10. The standpipe 26 ends in the interior of the hydraulic block 10 in a blind hole-like manner at a level below the pipe connection 24 for the master brake cylinder.

[0019] Due to the effective gravity buoyancy, any bubbles that may occur enter the standpipe 26 on the suction side of the pump element and rise inside the standpipe 26 toward its closed end. The bubbles accumulate here. The region from which the driven pump element draws brake fluid is thus substantially free of bubbles, and thus bubbles are prevented from being pushed toward the pressure side of the pump element.

[0020] The standpipe 26 itself is part of a hydraulic cavity 28 formed within the brake circuit, which helps to avoid pulsations on the suction side of the pump element and to reduce the operating noise of the hydraulic assembly. For this purpose, the volume of the hydraulic cavity 28 corresponds to the maximum pressure medium volume and / or the maximum volume of gas, wherein the pressure medium volume flows back to the suction side of the pump element via the not yet closed inlet valve during the compression phase of the pump element; the gas can be released from the pressure medium volume contained in the brake circuit by heating the brake fluid to its maximum operating temperature. The volume of the standpipe 26 alone that can be shown may not be sufficient in certain cases. For these cases, one or more additional hydraulic cavities 28 can be provided on the hydraulic block and connected to the standpipe 26. Various variants of the additional cavities 28 are shown in the figures explained in more detail below. All of these additional cavities 28 extend from one of the outer sides of the hydraulic block 10 into the interior of the hydraulic block 10 and are connected to one another via the mentioned standpipes 26. Furthermore, an additional cavity 28 is arranged in a region of the hydraulic block 10 which is located between the receptacles 12 , 14 for pump elements and the pipe connections 22 , 24 of the hydraulic block 10 .

[0021] In accordance with Figure 2 In the case of the variant shown, the cavity 28 comprises, in addition to the standpipe 26, a horizontal hole 30 opening into the left outer side of the hydraulic block 10. The horizontal hole 30 is arranged at the level of the inner end of the standpipe 26 and intersects the standpipe 26 in a T-shape. The horizontal hole 30 and the standpipe 26 have, for example, approximately the same inner diameter, but this is not mandatory.

[0022] In accordance with Figure 3 In the variant shown, the entire cavity 28 consists of the vertical tube 26 and a plurality of horizontal holes 30a, 30b, 30c extending coaxially with one another, which intersect the vertical tube 26 at different heights and extend, for example, to both sides of the vertical tube 26. For example, all horizontal holes 30a, 30b, 30c start from the left outer side of the hydraulic block 10. The openings of the horizontal holes 30a, 30b, 30c facing the outer side are closed by sealing means in the fully assembled hydraulic assembly. Known sealing means are, for example, balls, which are preferably pressed into the area of ​​the openings in the horizontal holes 30a, 30b, 30c and thereby seal them off from the environment in a pressure medium-tight manner. As an alternative to the balls, for example, plugs, screw plugs or disc-shaped covers can also be used.

[0023] Figure 4The cavity 28 is shown, which, in addition to the standpipe 26, comprises two vertically intersecting blind holes 32a, 32b. The first of the two blind holes 32a extends horizontally at the level of the inner end of the standpipe 26 and starts from the left outer side of the hydraulic block 10, while the second blind hole 32b extends inwards starting from the upper side of the hydraulic block 10, vertically and offset in parallel with the standpipe 26 axis and opens into the first blind hole 32a at its end. In this case, the corresponding openings of the blind holes 32a, 32b are also closed in a pressure-medium-tight manner in the assembled hydraulic assembly, for example by pressed and / or caulked plugs, covers or balls.

[0024] exist Figure 5 In the embodiment of the present invention, the standpipe 26 contacts a chamber 34, the inner diameter of which is significantly larger than the inner diameter of the standpipe 26 and which has a relatively small depth. The opening of the chamber 34 to the environment is closed by a sealing cover 36, which is caulked or otherwise fastened to the hydraulic block 10 in a form-fitting and / or friction-locking manner on the circumference.

[0025] Of course, any desired combinations of the cavity variants described are also possible. Figure 6 For example, a combination is shown. In this embodiment, the entire cavity is formed by a standpipe 26 and a plurality of horizontal holes 30a, 30b, 30c of blind hole-like construction starting from the left outer side of the hydraulic block and at least one vertical hole relative to the upper side of the hydraulic block 10 and a chamber 34 leading to the front side of the hydraulic block 10.

[0026] In accordance with Figure 7 In the embodiment shown, the opening of the chamber 34 is located, for example, on the left outer side of the hydraulic block 10. The horizontal hole 30 connects the interior of the chamber 34 to the standpipe 26.

[0027] exist Figure 8 Another embodiment variant shown in , for example, comprises two chambers 34a, 34b, the openings of which lead to different outer sides of the hydraulic block 10. The first chamber 34a is designed, for example, to face the front of the hydraulic block 10, while the opening of the second chamber 34b is located, for example, on the left outer side of the hydraulic block 10. The standpipe 26 passes through the first chamber 34a and leads to a horizontal hole 30 designed in the form of a blind hole, which in turn leads to the second chamber 34b. Embodiment variants with more than two chambers 34 are also conceivable.

[0028] Of course, the cavities 28 disclosed in the various exemplary embodiments can be adapted to the respective use of the hydraulic assembly in any desired number, orientation and combination of their individual cavities. Overall, the cavities 28 each comprise a riser 26 which forms a connection to the receptacles 12, 14 for the pump elements and which, with respect to the position of the pump elements on the hydraulic block 10, faces the upper side of the hydraulic block 10 with the pipe connections 22, 24. As already explained, existing gas bubbles can thus rise due to the effective force of gravity via the riser 26 toward the upper side of the hydraulic assembly and accumulate at the end of the cavity 28 facing away from the pump element.

[0029] Finally, it should be pointed out that the above embodiments each show the construction of a hydraulic cavity 28 including a standpipe 26 in one of the existing brake circuits. In principle, it is conceivable that a hydraulic cavity 28 constructed in this way is present only in one brake circuit or in each existing brake circuit. The cavities 28 of the individual brake circuits can be constructed identically or differently with respect to their total volume, the arrangement and / or configuration of the individual cavities connected to one another.

[0030] Of course, other improvements or supplements to the described embodiments are also conceivable without departing from the basic idea of ​​the invention as claimed.

Claims

1. A hydraulic assembly for regulating the brake pressure in a wheel brake of an electronically slip-controlled brake system of a motor vehicle, the hydraulic assembly comprising: A hydraulic block (10) having a receptacle (12, 14) for receiving a pump element; a pipe joint (22) at the hydraulic block (10), the pipe joint being used to bring the hydraulic assembly into contact with the wheel brake; a channel (20) leading to a receptacle (12, 14) for the pump element, the channel being used to supply brake fluid to the pump element inserted into the receptacle (12, 14), wherein the channel (20) connects a storage chamber (18) for brake fluid on the hydraulic block (10) to the suction side of the pump element inserted into the receptacle (12, 14); and a hydraulic cavity (28) formed within the hydraulic block (10) and in contact with the receptacle (12, 14) in the region of the suction side of a pump element inserted into the receptacle (12, 14), It is characterized in that The pipe connection (22) is arranged at or in the region of the upper side of the hydraulic assembly, and The hydraulic cavity (28) comprises a riser pipe (26) which forms a blind hole terminating inside the hydraulic block (10) and which extends from a receptacle (12, 14) for the pump element toward the pipe connection (22).

2. The hydraulic assembly according to claim 1, It is characterized in that The hydraulic cavity (28) has an opening facing one of the outer sides of the hydraulic block (10), which opening can be closed by a sealing element that can be anchored on the hydraulic block (10).

3. The hydraulic assembly according to claim 1, It is characterized in that The hydraulic cavity (28) is arranged in a region of the hydraulic block (10) which is located between a receptacle (12, 14) for the pump element and a pipe connection (22) of the hydraulic block (10).

4. The hydraulic assembly according to claim 2, It is characterized in that The hydraulic cavity (28) is arranged in a region of the hydraulic block (10) which is located between a receptacle (12, 14) for the pump element and a pipe connection (22) of the hydraulic block (10).

5. The hydraulic assembly according to claim 1, in, A storage chamber (18) for accommodating brake fluid is provided on the hydraulic block (10), the storage chamber being in contact with the receptacle (12, 14) for the pump element via a channel (20). It is characterized in that The standpipe (26) is designed as a straight extension of a channel (20) which brings the storage chamber (18) into contact with the receptacle (12, 14) for the pump element.

6. The hydraulic assembly according to claim 5, It is characterized in that A channel (20) connecting the storage chamber (18) to the receptacle (12, 14) for the pump element and the standpipe (26) open on opposite sides to the receptacle (12, 14) for the pump element and extend coaxially with respect to one another.

7. The hydraulic assembly according to any one of claims 1 to 6, It is characterized in that The riser (26) forms a blind hole which ends inside the hydraulic block (10).

8. The hydraulic assembly according to any one of claims 1 to 6, It is characterized in that The total volume of the hydraulic cavity (28) is matched to a pressure medium volume which, during the compression phase, presses the pump element until an inlet valve of the pump element is closed.

9. The hydraulic assembly according to any one of claims 1 to 6, It is characterized in that The total volume of the hydraulic cavity (28) corresponds to the volume of gas that may be released from the brake fluid when the brake fluid is heated to a maximum operating temperature.

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