Pump device for a brake system of an automobile, brake system

Abstract

To individually secure easy assembly of a pump device and desired fluid pressure.SOLUTION: A pump device 9 for a brake system 1 of an automobile, includes: a housing 10; a pressure piston 11 which partitions a pressure chamber 20 for generating fluid pressure in the housing and which is supported in the housing in a slidable manner in a longitudinal direction; a return spring 23 attached to the pressure piston; a check valve 15 which divides the pressure chamber from a pressure connection part 3 and cancels the division only when the fluid pressure in the pressure chamber is higher than that at the pressure connection part; and an electromagnetic actuator having a magnetic armature 21 and electrically conductive magnetic coil 22, the magnetic armature being provided to the pressure piston and the magnetic coil being provided in and / or on a surface of the housing. The pressure piston includes an axial through passage 19 having one end communicating with the pressure chamber and the other end being attached to the check valve.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pump device for a braking system of a motor vehicle, comprising a housing, a pressure piston supported in the housing so as to be longitudinally slidable and defining a pressure chamber for generating a hydraulic pressure in the housing, a return spring associated with the pressure piston, a check valve for isolating the pressure chamber from a pressure connection and for removing the decoupling only when the hydraulic pressure in the pressure chamber is higher than in the pressure connection, and an electromagnetic actuator having a magnetic armature and an electrically energizable magnetic coil, the magnetic armature being arranged on the pressure piston and the magnetic coil being arranged in and / or on the housing.

[0002] The invention further relates to a brake system having at least one brake circuit with at least one hydraulically actuable wheel brake and at least one pump device for generating hydraulic pressure in the brake circuit. [Background technology]

[0003] Pump arrangements and brake systems of the type mentioned at the outset are known from the prior art. In order to enable hydraulic wheel brakes to be actuated independently of brake pedal actuation or, depending on brake pedal actuation, to apply pressure to the wheel brakes when the hydraulic or mechanical connection from the brake pedal to the wheel brakes is interrupted, it is known to provide a brake circuit with a controllable, in particular electrically controllable, pump arrangement. A piston that reciprocates in an oscillatory manner is used to generate hydraulic pressure in a pressure chamber and to provide it to the brake system or brake circuit. A corresponding pump arrangement is known, for example, from DE 199 10 200 43 33 A1. There, the pump piston is driven by an electromagnetic actuator against the force of a return spring to perform the pumping movement or pumping process. A check valve prevents hydraulic medium from flowing back from the pressure connection to the pressure chamber, since it automatically closes the connection between the pressure chamber and the pressure connection when the pressure in the pressure connection is higher than the pressure in the pressure chamber. This ensures reliable intake and discharge of the sucked-in hydraulic medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] German Patent Application Publication No. 102014204157A1 Summary of the Invention

[0005] The pump arrangement according to the invention having the features of claim 1 has the advantage that, with reduced design space requirements, the pump arrangement according to the invention ensures simple assembly as well as individual provision of the desired hydraulic pressure.

[0006] The pump device according to the invention having the features of claim 1 is characterized in that the pressure piston has an axial through-passage which communicates with the pressure chamber at one end and which is associated with or faces the non-return valve at the other end. The hydraulic medium which is in the pressure chamber and which is applied with pressure by the pressure piston movement is thereby pumped through the pressure piston to the non-return valve and thus to the pressure connection. The pressure piston is thereby pumped out of the pump device in the opposite direction to the flow direction of the hydraulic medium which is applied with pressure. The through-passage of the pressure piston thereby allows a particularly compact design of the pump device. This particularly preferred design allows the pump device as a whole to be designed as a plug-in device which can be easily plugged in for assembly into the receiving part of the hydraulic block, so that a particularly easy assembly is achieved by the pump device which is pre-assembled or can be pre-assembled as a whole.

[0007] In a preferred development of the invention, the pressure piston has a first end face associated with the pressure chamber and a second end face associated with the non-return valve, the cross-sectional area of ​​the first end face being greater than the cross-sectional area of ​​the second end face. In particular, the total cross-sectional area of ​​the first end face is greater than the total cross-sectional area of ​​the second end face. This provides that the volume of the pressure chamber, which is reduced by the movement of the pressure piston in the pressure chamber, is greater than the volume at the end of the pressure piston associated with the non-return valve, which is possibly released by the movement of the pressure piston. This reliably ensures the generation of the desired hydraulic pressure as well as the pumping of the hydraulic medium in the desired direction.

[0008] It is furthermore preferably intended that the return spring is held prestressed between the first end face and the closed end face of the housing which delimits the pressure chamber. The return spring is therefore located as a whole in the pressure chamber which is delimited by the housing, the first end face of the pressure piston and the closed end face of the housing. The displacement of the pressure piston changes the volume of the pressure chamber, whereby the desired hydraulic pressure is ensured. The arrangement of the return spring in the pressure chamber provides a design space-optimized configuration and, moreover, the return spring is protected against external factors inside the pressure chamber, which ensures high durability and functionality of the pump device.

[0009] Furthermore, it is preferably provided that the pressure piston has an intake valve for connecting the suction connection with the pressure chamber, the intake valve being constituted by a valve sleeve longitudinally slidably supported in the pressure piston, which together form a pressure passage. In this way, in the pressure piston, which is longitudinally slidably displaceable relative to the housing, a valve sleeve, which is longitudinally slidably displaceable relative to the pressure piston as a whole, is arranged, thereby connecting or decoupling the suction connection with the pressure chamber. The integral construction of the valve sleeve on the pressure piston, as well as the joint formation of the pressure passage by the valve sleeve, provides a particularly compact embodiment of the pump device. In addition to this, the intake valve is advantageously and easily integrated into the pump device in terms of assembly technology. The return spring is preferably located radially spaced from the valve sleeve, so that the valve sleeve does not cooperate with the return spring but can be displaced independently of the pressure piston or the return spring force.

[0010] Furthermore, the pressure piston preferably has at least one radial opening in its casing which is associated with the suction connection and which is hydraulically connected to the suction connection in each sliding position of the pressure piston, thereby ensuring that the suction connection passes through the pressure piston and is always hydraulically connected to the valve sleeve or intake valve.

[0011] It is furthermore preferably provided that the valve sleeve has at least one axial passage in its outer wall, which connects a radial opening of the pressure piston with the pressure chamber when the valve sleeve is in the first sliding position of the pressure piston and separates it from the pressure chamber when the valve sleeve is in the second sliding position. Thus, when the valve sleeve is in the first sliding position, the suction connection is connected with the pressure chamber through the pressure piston or through the radial opening of the pressure piston and through the axial passage. When the valve sleeve is displaced into the second sliding position, this connection is interrupted, in particular by the closing of the axial passage by the valve sleeve. This ensures a simple and reliable operation of the intake valve.

[0012] It is particularly preferred that the valve sleeve has an annular sealing seat at its end facing the pressure chamber, which abuts against the pressure piston in the second sliding position so as to close the axial passage and which is spaced apart from the pressure piston in the second sliding position. In this way, the axial passage can be closed by the sealing seat of the valve sleeve. At the same time, the sealing seat defines the maximum penetration depth of the valve sleeve into the pressure piston, which ensures easy assembly as well as reliable functioning of the intake valve.

[0013] The axial passage is preferably configured as a groove-like recess in the outer surface of the jacket wall of the valve sleeve, which provides an open-edged axial passage that can be implemented at lower cost compared to a completely closed axial passage on the circumferential side. On the circumferential side, the axial passage is formed on the one hand by the groove-like recess of the valve sleeve and on the other hand by the inner wall of the pressure piston, which allows a favorable cooperation between the valve sleeve and the pressure piston and in particular a simple closing of the axial passage by the sealing seat already described above.

[0014] It is further provided that the axial passage is preferably configured as a circumferential groove on the outer surface of the casing wall of the valve sleeve, so that the axial passage extends over the entire circumference of the valve sleeve and is configured annular in that sense, whereby on the one hand a high volumetric flow rate is ensured and on the other hand clogging of the axial passage is reliably prevented even in the presence of dirt or harmful particles.

[0015] The magnetic armature is preferably axially fitted onto the pressure piston, which ensures easy positioning of the magnetic armature on the pressure piston.

[0016] It is particularly preferred that the magnetic armature is connected in an axially positive manner to the pressure piston, in particular by plastic deformation, preferably by at least one crimping. The positive connection ensures that the magnetic armature always moves together with the pressure piston, so that the cooperation of the electromagnetic actuator, the pressure piston and the return spring is always ensured.

[0017] It is particularly preferred that the housing is configured as a plug-in housing for plugging into the hydraulic block of the brake system and has at least one radial projection on its outer surface in order to ensure axial fixing of the housing in or on the hydraulic block, in particular by plastic deformation of the hydraulic block. The configuration as a plug-in housing ensures a simple assembly of the pump device in the hydraulic block of the brake system. The plug-in housing is characterized in particular by having a diameter that decreases in the plug-in direction or a cross-sectional area that decreases / drops or remains the same, except for the radial projection, in order to avoid undercuts and / or gap spaces in the housing. This provides a favorable and secure form-fitting arrangement of the housing and / or the pump device in the hydraulic block. The radial projection limits, for example, the penetration depth of the plug-in housing into the hydraulic block. Furthermore, the radial projection serves to ensure that the plug-in housing and thus the pump device can be locked in the hydraulic block, in particular by plastic deformation of the hydraulic block, whereby unintentional removal of the pump device from the hydraulic block is also reliably prevented.

[0018] It is particularly preferred that the housing is multi-part, with a first housing part for receiving and supporting the pressure piston and the non-return valve, and a second housing part for forming the pressure chamber, in particular for slidably supporting the magnetic armature, which housing parts are fixedly connected to one another. The multi-part housing design ensures a reliable and simple pre-assembly of the pump device before placement in or on the hydraulic block of the brake system. Furthermore, the preferred design for supporting the magnetic armature ensures a reliable guidance of the magnetic armature in the housing of the pump device. The fixed connection of the housing parts to one another allows a preferred pre-assembly.

[0019] The housing parts are preferably permanently connected to one another by plastic deformation, in particular by crimping, so that unintentional uncoupling is reliably prevented and the connection of the housing parts to one another is permanently and reliably guaranteed, in particular a form-fitting connection providing a particularly robust connection which is permanently guaranteed even under high hydraulic pressures.

[0020] The brake system according to the invention having the features of claim 15 is characterized in that it has the inventive configuration of the pump device, which results in the advantages already mentioned. In particular, this brake system has a hydraulic block with one or more receiving recesses for respectively receiving the pump devices according to the invention. In particular, the receiving recesses are configured as plug-in receiving recesses, so that the respective pump devices can be easily inserted into the respective receiving recesses and are fixed there to the hydraulic block, in particular by plastic deformation of the hydraulic block.

[0021] Further advantages and preferred features and feature combinations will become apparent, inter alia, from the above description and the appended claims.The invention will now be described in more detail with reference to the drawings, in which: FIG. [Brief description of the drawings]

[0022] [Figure 1] 1 is a simplified cross-sectional view of a preferred braking system for a motor vehicle, showing a first operating condition; [Diagram 2] FIG. 4 is a simplified longitudinal section view of a pump device of the brake system in a second operating state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] FIG. 1 shows in a simplified longitudinal section a part of a preferred brake system 1 for a motor vehicle, which is not shown in detail here. The brake system 1 has a hydraulic block 2, in which the pressure and suction passages of the brake system for the hydraulic medium, in particular for the brake fluid, are integrated. For example, the area of ​​the hydraulic block 2 shown in FIG. 1 has a pressure connection 3, from which two pressure passages 4 branch off, for example leading to different brake circuits or to friction brakes of a common brake circuit. Furthermore, this area of ​​the hydraulic block 2 shows a suction connection 5, into which two suction passages 6 communicate, in particular with a tank for supplying and storing the hydraulic medium and / or with a master brake cylinder of the brake system 1.

[0024] The pressure passage 4 and the suction passage 6 communicate with a cylindrically configured receiving recess 7 of the hydraulic block 2, the diameter of which, starting from its bottom surface 8, only increases in the direction of the free access opening and does not decrease, except for any subsequent plastic deformations that may occur.

[0025] A pump device 9 is inserted into the receiving recess 7 , by means of which hydraulic medium can be pumped from the suction connection 5 to the pressure connection 3 , the pump device 9 itself decoupling the suction connection 5 from the pressure connection 3 .

[0026] For this purpose, the pump device 9 has a housing 10 configured as a plug-in housing, the outside diameter of which corresponds at least essentially to the inside diameter of the receiving recess 7, so that, as shown in Fig. 1, the housing 10 is plugged into the receiving recess 7 in a form-fitting manner, at least essentially without clearance, in this sense the receiving recess is configured as a plug-in receiving recess. In particular, the outside diameter of the housing 10 is slightly larger than the inside diameter of the receiving recess 7, so that a press fit between the housing 10 and the hydraulic block 2 is established in the plug-in state, whereby the pressure connection 3 or the pressure side is reliably decoupled from the suction connection 5 or the suction side.

[0027] A pump piston 11 is mounted in a housing 10 of the pump device 9 so that it can slide longitudinally. For this purpose, the housing 10 is configured like a sleeve with a dish-shaped receiving portion 12 for the pressure piston 11. At the bottom of the dish-shaped receiving portion 12, the housing 10 has a discharge opening 13 with an associated discharge valve 14 in the form of a non-return valve 15. The non-return valve 15 has a spherical valve member 16 which cooperates with a sealing seat 17 formed by the side of the housing 10 facing away from the pressure piston 11 in order to seal and close the discharge opening 13. A return spring 18, only suggested here, presses the valve member 16 into the valve seat 17, so that in normal condition the discharge opening 13 which communicates with the pressure connection 3 is closed.

[0028] The pressure piston 11 has a through passage 19 extending axially through it, so that the pressure passage 19 faces one end of the discharge valve 14. The other end of the pressure passage 19 faces a pressure chamber 20 bounded by the pressure piston 11 and the housing 10. At its end facing the pressure chamber 20, the pressure piston 11 carries a magnetic armature 21 which is arranged to cooperate with a magnetic coil 22 arranged outside the housing 10. The magnetic armature 21 is guided in the housing 10 so as to be longitudinally slidable.

[0029] Furthermore, a return spring 23 is arranged in the pressure chamber 20, which is held prestressed between the pressure piston 11 and the housing 10. The pressure piston 11 has a first end face 24 facing the pressure chamber 20, facing a closed end face 25 of the housing 10, so that the return spring 23 is held prestressed between the first end face 24 and the end face 25. The end face 24 is hereby formed together by the magnetic armature 21 in the present embodiment. The magnetic armature 21 is connected to the pressure piston 11 in a form-fitting manner, so that the pressure piston 11 and the magnetic armature 21 always move together with one another. For the form-fitting connection, it is intended in the present embodiment that the magnetic armature is connected by a crimp 26 which engages in a radial recess 27 of the piston 11. The magnetic armature 21 thus forms part of the pressure piston 11.

[0030] The through passage 19 of the pressure piston 11 is formed by a stepped bore, in the area of ​​which facing the pressure chamber 20 a valve sleeve 28 is mounted so as to be able to slide longitudinally. With its free end facing the pressure chamber 20 the valve sleeve 28 projects axially from the body of the piston 11 and has a sealing seat 29 at said end. At its outer surface at its casing wall the valve sleeve 28 has an axial passage 30 in the form of a circumferential groove which extends over the entire circumference of the valve seat 28. The circumferential groove 30 is then designed so that, irrespective of its sliding position, it is always hydraulically connected to a radial opening 31 designed in the pressure piston 11. The radial opening 31 of the pressure piston 11 is then designed so that, irrespective of the sliding position of the pressure piston 11, it is always hydraulically connected to the suction connection 5.

[0031] 1, the sealing seat 29 rests axially against the pressure piston 11, so that the axial passage 30 extending between the inner wall of the pressure piston 11 and the outer wall of the valve sleeve 28 is closed. The hydraulic connection from the suction connection 5 to the pressure chamber 20 is thereby interrupted.

[0032] Starting from the above-described state, the following function is achieved: When the magnetic coil 22 is supplied with a current or voltage, an electromagnetic field is generated which cooperates with and attracts the magnetic armature 21, which further compresses or stresses the return spring 23. The attraction of the magnetic armature 21 causes the pressure piston 11 to slide towards the pressure chamber 20, which in turn reduces the pressure chamber 20. The internal pressure in the pressure chamber 20 which arises during the reciprocating movement of the pressure piston 11 ensures that the valve sleeve 28 is pressed axially towards the pressure piston 11, thereby closing the axial passage 30. The pressure exerted on the hydraulic medium present in the pressure chamber 20 acts in such a way that the hydraulic medium reaches the discharge valve 13 through the through passage 19 which is formed together with the valve sleeve 28. If the pressure is then higher than the pressure in the pressure connection 3 and the return force of the optional return spring 18, the valve member 16 is displaced from the closed position shown in FIG. 1 to an open position which frees the discharge opening 13, and the hydraulic medium flows into the pressure connection 3 and thus into the pressure passage 4.

[0033] When the magnetic coil 22 is de-energized, the return spring 23 presses the pressure piston 11 back to its initial position. In this respect, Fig. 2 shows the pump device 9 again in a simplified longitudinal section, but in a second operating state, in which the intake valve formed by the valve sleeve 28 and the pressure piston 11 is open. The return sliding of the pressure piston 11 expands the gap between the valve sleeve 28 and the pressure piston 11 at the sealing seat 29, so that the hydraulic medium can flow from the suction connection 5 into the pressure chamber 20, as shown by the arrow in Fig. 2. During the return movement of the pressure piston 11, the pressure chamber 20 expands again, creating a negative pressure, which pulls the valve sleeve 28 away from the pressure piston 11, so that the sealing surface 28 comes off the pressure piston 11, thereby opening the intake valve and, as a result, the hydraulic medium can flow from the suction connection 5 into the pressure chamber 20.

[0034] However, the return spring is present in this position only as an option. In an alternative embodiment, the valve member 14 is pressed sealingly against the valve seat 17 solely by the static pressure of the pressure connection 3.

[0035] For easy assembly of the brake system 1 and in particular the pump device 9, the housing 10 of the pump device 9 has at least one radial projection 34 on its outer wall. After the housing 10, in particular the pre-assembled pump device 9 together with the housing 10, has been inserted into the receiving recess 7, the hydraulic block 2 is plastically deformed in the region of the radial projection 34, in particular by crimping, as shown in Fig. 1, so that the radial projection 34 is engaged at the rear by the material of the hydraulic block 2, as shown by the crimp 32 in Fig. 1. The pump device 9 is thereby reliably and permanently held in the hydraulic block 2, in particular sealingly.

[0036] For even easier assembly, the housing 10 has several parts. In the present embodiment, the housing 10 is made up of two parts, the first housing part 10_1 being the already mentioned plug-in housing which is inserted into the receiving recess 7. The second housing part 10_2 is attached to the housing part 10_1 at the end of the housing part 10_1 facing away from the discharge opening 13. For this purpose, the cup-shaped housing part 10_2 is inserted into the housing part 10_1 and is permanently connected to the housing part 10_1 in a form-fitting manner by plastic deformation, as shown in FIG. 1 by the crimping 33 of the housing part 10_1. The housing part 10_2 here forms the pressure chamber 20 together with the pressure piston 11 and also serves for the longitudinally slidable support in the housing 10 of the magnetic armature 21 and thus of the pressure piston 11.

[0037] In particular, the valve sleeve 28 is slidably supported in the pressure piston 11 with a slight movement with only a small leakage and has through-flow openings extending in the longitudinal direction of the valve sleeve 28 and forming together the through passage 19 due to the sleeve shape. The pressure piston 11 as well as the magnetic armature 21 as a whole are preferably made of a magnetically conductive material in order to improve the action of the electromagnetic actuator. The valve seats at the outlet opening 13 and also at the intake opening which can be formed between the valve sleeve 28 and the pressure piston 11 are preferably made of plastic in order to achieve a high sealing effect by elastic deformation at least in partial areas in the closed state. The magnetic decoupling of the magnetic armature 29 and the pole faces of the magnetic coil can be realized by a thin wall thickness at the housing 10. The contour of the pressure piston 11 is preferably configured in such a way that the force on the pressure piston 11 remains at least substantially equal or constant over its entire stroke.

[0038] The preferred configuration of the pump device 9 as a plug-in or insert module or in the form of a cartridge ensures a simple installation of the pump device 9 in / on the hydraulic body 2. The hydraulic body 2 preferably has a number of receiving recesses 2 into which correspondingly designed pump devices 9 can be plugged, thereby ensuring a simple installation of the brake system 1 as a whole. It is particularly preferred that the pump device is produced as a pre-installed module yet without a magnetic coil, thereby ensuring a simple insertion and locking of the pump device 9 in the hydraulic 2. The magnetic coil 22 is then subsequently installed. The magnetic armature 29 itself is flowed through by the hydraulic medium, which results in a good cooling of the electromagnetic actuator.

[0039] The fact that the pump devices 9 can be individually actuated electromagnetically results in a design-space-saving configuration of the pump device as well as in an individual control of a number of pump devices 9 that may be present. In addition, movable seals to the outside can be dispensed with, so that no risk of leakage or air intake occurs. In addition, the configuration of the magnetic coil 22 as a separate component offers the advantage of a modular system that allows for simplified assembly. [Explanation of symbols]

[0040] 1 Brake system 2 Hydraulic Block 3 Pressure Connection 5 Suction connection 9. Pumping Equipment 10. Housing 10_1,10_2 Housing part 11 Pressure Piston 15 Check valve 19 Passageway 20 Pressure Chamber 21 Magnetic Armature 22 Magnetic Coil 23 Return spring 24 First end face 26 Crimping 28 Valve sleeve 29 Seal Sheet 30 Axial passage 31 Radial opening 33 Crimping 34 Radial projection

Claims

1. The device comprises a housing (10), a pressure piston (11) supported in the housing (10) so as to be longitudinally slidable, which defines a pressure chamber (20) for generating a hydraulic pressure in the housing (10), a return spring (23) associated with the pressure piston (11), a check valve (15) which separates the pressure chamber (20) from a pressure connection (3) and which releases the separation only when the hydraulic pressure in the pressure chamber (20) is higher than the hydraulic pressure in the pressure connection (3), a magnetic armature (21), and and an electromagnetic actuator having an electrically conductive magnetic coil (22), said magnetic armature (21) being arranged on said pressure piston (11) and said magnetic coil (22) being arranged in and / or on said housing (10), said pressure piston (11) having an axial through passage (19) communicating at one end with said pressure chamber (20) and at the other end with said check valve (15), 1. A pump device comprising: a pressure piston (11) having an intake valve for connecting a suction connection (5) with the pressure chamber (20), the intake valve being configured as a valve sleeve (28) longitudinally slidably supported in the pressure piston (11) and forming together with the through passage (19).

2. 2. The pump device according to claim 1, wherein the pressure piston (11) has a first end face (24) associated with the pressure chamber (20) and a second end face (24) associated with the non-return valve (15), the cross-sectional area of ​​the first end face (24) being greater than the cross-sectional area of ​​the second end face (24).

3. 3. The pump device according to claim 2, characterized in that the return spring (23) is held prestressed between the first end face (24) and a closed end face of the housing (10) which bounds the pressure chamber (20).

4. 4. The pump device according to claim 1, wherein the pressure piston (11) has in its outer wall at least one radial opening (31) associated with the suction connection (5), which is hydraulically connected to the suction connection (5) in every sliding position of the pressure piston (11).

5. 5. The pump device according to claim 4, characterized in that the valve sleeve (28) has in its outer wall at least one axial passage (30) which connects the radial opening (31) of the pressure piston (11) with the pressure chamber (20) when the valve sleeve (28) is in a first sliding position inside the pressure piston (11) and separates it from the pressure chamber (20) when the valve sleeve (28) is in a second sliding position inside the pressure piston (11).

6. 6. The pump device according to claim 5, characterized in that the valve sleeve (28) has, at its end facing the pressure chamber (20), an annular sealing seat (29) which abuts against the pressure piston (11) so as to close the axial passage (30) in the second sliding position and which is spaced apart from the pressure piston (11) so as to open the axial passage (30) in the first sliding position.

7. 7. A pump arrangement according to claim 5 or 6, characterized in that the axial passage (30) is configured as a groove-like recess in the outer surface of the outer wall of the valve sleeve (28).

8. 8. A pump arrangement according to claim 5, wherein the axial passage (30) is configured as a circumferential groove in the outer surface of the outer wall of the valve sleeve (28).

9. 9. The pump device according to claim 1, wherein the magnetic armature (21) is fitted axially on the pressure piston (11).

10. 10. The pump device according to claim 1, wherein the magnetic armature (21) is connected in an axially positive manner with the pressure piston (11).

11. 11. The pump device according to claim 1, wherein the housing (10) is configured as a plug-in housing for being plugged into a hydraulic block (2) of the brake system (1) and has at least one radial protrusion (34) on its outer surface to ensure axial fixation of the housing (10) on the hydraulic block (2) by plastic deformation of the hydraulic block (2).

12. 12. The pump device according to claim 1, wherein the housing (10) is multi-part and comprises a first housing part (10) for accommodating and supporting the pressure piston (11) and the check valve (15) and a second housing part (10) for closing the pressure chamber (20) and for slidably supporting the magnetic armature (21), the housing parts (10_1, 10_2) being fixedly connected to one another.

13. 13. The pump device according to claim 12, characterized in that the housing parts (10_1, 10_2) are connected to each other by plastic deformation.

14. A hydraulic device comprising: a housing (10); a pressure piston (11) supported in the housing (10) so as to be capable of sliding in the longitudinal direction, the pressure piston (11) separating a pressure chamber (20) for generating hydraulic pressure in the housing (10); a return spring (23) attached to the pressure piston (11); a check valve (15) separating the pressure chamber (20) from a pressure connection part (3) and releasing the separation only when the hydraulic pressure in the pressure chamber (20) is higher than the hydraulic pressure in the pressure connection part (3); a magnetic armature (21); and an electromagnetic actuator having an electrically conductive magnetic coil (22), said magnetic armature (21) being arranged on said pressure piston (11) and said magnetic coil (22) being arranged in and / or on said housing (10), said pressure piston (11) having an axial through passage (19) communicating at one end with said pressure chamber (20) and at the other end with said check valve (15), 1. A pump device comprising: a pressure piston (11) having in its outer wall at least one radial opening (31) associated with a suction connection (5) which is hydraulically connected to the suction connection (5) in every sliding position of the pressure piston (11); and wherein the suction connection (5) is hydraulically connected to the pressure chamber (20) in at least one sliding position of the pressure piston (11).

15. 15. A brake system (1) for a motor vehicle having at least one brake circuit with at least one hydraulically actuable wheel brake and at least one pump device (9) for generating hydraulic pressure in said brake circuit, characterized in that the pump device (9) has a configuration as claimed in any one of claims 1 to 14.

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