Electromechanically operable pressure medium control valve

Abstract

The invention relates to an electromechanically operable pressure-medium control valve (10), which comprises a valve housing (12), an armature (14), a pole core (18), a valve sleeve (20) with a control cross-section (26.1) and a closure body (16) for controlling the pressure-medium flow through the control cross-section (26.1). [Solution] Proposed is a development of such a pressure medium control valve (10), which allows for different throttling of the pressure medium flow between the first valve opening (26) and the second valve opening (28) depending on the flow direction of the pressure medium flow through the pressure medium valve (10).

Description

[Technical field]

[0001] The invention relates to an electromechanically actuable pressure medium control valve according to the features of the preamble of claim 1 . [Background technology]

[0002] A pressure medium control valve of this kind is already known, for example from DE 10 200 03 133 A1.

[0003] The known pressure medium control valve is, for example, a two-stage change-over valve which is closed in the de-energized state and interrupts the pressure medium connection between two valve ports, i.e. inlet and outlet. The valve is actuated via an electrically operable valve coil which, when energized, generates a magnetic field which acts on an armature. The armature thus performs a stroke movement in the direction of the longitudinal axis of the valve. The armature movement is limited in one direction by a pole core, and on the side of the armature facing away from the pole core a valve sleeve is arranged, on which a control cross section of the pressure medium control valve is formed. To control this control cross section a closing body is provided which can be actuated by the armature.

[0004] Multi-stage valves are required to control a high volume flow rate of pressure medium at low pressure or to control high pressures. Typically, in these valves, a front stage with a relatively small control cross section opens first, and only subsequently does a main stage, which releases the largest control cross section of the pressure medium control valve, open.

[0005] For example, in electronically pressure-adjustable vehicle brake systems, a multi-stage valve is used to control the pressure medium connection between a master brake cylinder and a pedal stroke simulator. The master brake cylinder is used in this context to detect the brake request of the driver of the motor vehicle. For this purpose, the master brake cylinder is connected to a lever or pedal that can be operated by the driver. The actuation stroke that correlates to the brake request is detected by measurement technology and transmitted to an electronic control device. The control device further processes the input signal into an operating control signal for an electrically driven pressure generator, which provides the desired brake jerk on the basis of the input signal.

[0006] The pressure medium displaced by actuation from the main brake cylinder reaches the pedal stroke simulator where it is buffered until the end of the braking process. The pedal stroke simulator itself exerts a reaction force on the pedal or lever that is proportional to the actuation stroke and which is perceptible by the driver as haptic feedback via the implemented pressure boost.

[0007] In practical use, it is increasingly the case that different volume flows must be controlled depending on the flow direction through the pressure medium control valve, which has been achieved up to now by a flow path parallel to the pressure medium control valve and controlled by a check valve, a so-called controllable bypass.

[0008] The disadvantage of this solution, however, is the additional space required for the parallel flow paths, as well as the costs for the necessary check valves and their assembly. Furthermore, multi-stage pressure medium control valves are expensive to manufacture due to the number of sealing points and have a higher leakage potential than single-stage valves. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] DE 102017213341 A1 Summary of the Invention Effect of the Invention

[0010] An electromechanically actuable pressure medium control valve according to the features of claim 1 has the advantage, in contrast, that the pressure medium control valve makes it possible to throttle the pressure medium flow to different degrees depending on the flow direction through which the pressure medium flows. A parallel flow path to the pressure medium control valve is not necessary for this purpose, and a check valve controlling the flow direction of this flow path can likewise be omitted.

[0011] Further advantages or advantageous developments of the invention can be seen from the dependent claims or the following description.

[0012] Preferably, the pressure medium control valve is equipped with a closing body, which is connected to the armature via a restraining device, which allows movement of the closing body relative to the armature in both forward and reverse stroke directions.

[0013] Due to these characteristics, the pressure medium control valve according to the invention has the advantage that it only requires a single control cross section or a single sealing point, which makes it more cost-effective to manufacture and reduces leakage.

[0014] In a particularly advantageous embodiment, the arresting device has a rotor capsule that is designed in a cup shape, in which the closure is slidably accommodated. Such a rotor capsule can be produced inexpensively, preferably by forming technology. Via the cup edge, the rotor capsule can be attached to the rotor in a simple force-locking manner.

[0015] The closure body itself is preferably designed as a tappet with a tappet stem and a tappet head, which controls the control cross section of the pressure-medium control valve. The tappet head projects from a through-hole in the cup bottom of the armature capsule. A mechanical stop projects radially from the tappet stem, by means of which the stroke movement of the closure body is limited in a first direction by the armature and in the opposite direction by the bottom of the armature capsule. The end of the tappet stem located opposite the tappet head is accommodated in a closure body guide on the armature. Via a pressure medium passage formed in the armature, this closure body guide is connected to one of the valve openings of the pressure-medium control valve, so that the closure body is pressure-biased towards the control cross section.

[0016] An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. The drawing comprises three views, each of which shows a pressure medium control valve according to the invention in longitudinal section. Corresponding components are given uniform reference numbers in the drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 3 shows the pressure medium control valve in the shut-off position. [Diagram 2] 2 shows the pressure medium control valve according to FIG. 1 in a first passage position, in which pressure medium flows through it in a first flow direction; [Diagram 3] 3 shows the pressure medium control in a second passage position in which the pressure medium flows in a direction opposite to the first flow direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] In the drawings, only the part of the pressure medium control valve which guides the pressure medium is shown, the electrically operable valve coil which operates the armature is omitted.

[0019] The pressure-medium-guiding part of the pressure-medium control valve 10 shown in FIG. 1 comprises, inter alia, a sleeve-shaped valve housing 12, an armature 14 accommodated in the valve housing 12 and guided so as to be freely slidable in the direction of the valve longitudinal axis L, a closing body 16 which is restrained by the armature 14 according to the invention, a pole core 18 which closes the valve housing 12 at one end, and a valve sleeve 20 which is arranged in the valve housing 12 on the side opposite the pole core 18.

[0020] The valve housing 12 is a slender, hollow, cylindrical component which is circumferentially widened in a step at its end facing the valve sleeve 20. This widening forms a shoulder 22 which projects radially away from the valve housing 12 and merges into an annular collar 24 at its outer end. The annular collar 24 extends in the direction of the valve longitudinal axis L and surrounds one of the open ends of the valve housing 12. The valve sleeve 20 is introduced into this open end until it abuts against the inner surface of the shoulder 22. The annular collar 24 surrounds the opposing sections of the valve sleeve 20 and is connected to the valve sleeve 20 in a force-locking manner. The valve sleeve 20 and the valve housing 12 are connected to one another accordingly to form a structural unit.

[0021] Towards the end of the valve sleeve 20 facing away from the valve housing 12, the valve sleeve 20 narrows in a bottleneck-like manner and terminates in an end face in which a first valve opening 26 is formed. This first valve opening 26 is arranged centrally with respect to the valve longitudinal axis L and forms a control cross section 26.1 oriented towards the interior of the valve housing 12 of the pressure medium control valve 10. The control cross section 26.1 is illustratively designed as a conical valve seat and is closed by an abutting closing body 16 in the representation shown in FIG. 1. A flat or spherical seat would also be possible.

[0022] A second valve opening 28 is formed as a cylinder bore in the neck of the valve sleeve 20. The second valve opening 28 is located in the region of the outer periphery of the valve sleeve 20 where a ring filter 30 is attached, so that the pressure medium flowing towards or out of the second valve opening 28 can be filtered and impurities removed.

[0023] A crimping ring 32 is placed on the cylindrical section of the valve housing 12. The crimping ring 32 rests on the outer surface of the shoulder 22 of the valve housing 12 and serves to press and hold the pressure medium control valve 10 in a valve receptacle (not shown) provided in a housing block. The peripheral contour of the crimping ring 32 is shaped in order to crimp the crimping ring 32 to the housing block. By means of a crimping tool, the material of the housing block is plastically deformed in such a way that the crimped material covers at least a partial section of the crimping ring 32.

[0024] The valve housing 20 protrudes from the mounting surface of the housing block with a housing section of the valve housing 20 that is located above the crimping ring 32 in FIG. 1. At this protruding end, the pole core 18 is introduced in part into the valve housing 12 and attached thereto. The end face of the pole core 18 that protrudes into the interior of the valve housing 12 serves as a first support for the valve spring 33. This valve spring 33 extends into the blind-hole-shaped valve spring receptacle 14.4 of the armature 14 and is secondarily supported in the valve spring receptacle 14.4. The armature 14 is directly opposite the pole core 18.

[0025] The armature 14 is divided into several successive longitudinal sections in the direction of the valve longitudinal axis L. Via guide sections 14.1, the armature 14 is guided in the axial direction on the inner wall of the valve housing 12. On the circumferential surface of the guide section 14.1, several longitudinal passages 34 are formed which run through and open outwardly, through which the pressure medium reaches an armature chamber 36 formed between the pole core 18 and the armature 14.

[0026] The guide section 14.1 extends into the valve sleeve 20, merges therein into a transition section 14.2 of the armature 14 and ends in a cylinder section 14.3, which has external dimensions significantly smaller than those of the guide section 14.1. Between the inner wall of the valve sleeve 20 and the circumferential surface of the armature 14 in the region of the transition section 14.2 and the cylinder section 14.3, a valve chamber 38 is formed, which is filled with pressure medium, and into which the above-mentioned longitudinal passage 34 in the guide section 14.1 opens.

[0027] In the center of the cylinder section 14.3, a closure body guide 40 is formed in the armature 14. This closure body guide 40 has a blind bore whose inside diameter is stepped from the outside to the inside and is connected to the valve chamber 38 via a pressure medium passage 42 which, for example, runs transversely to the blind bore. The second valve opening 28 formed in the neck section of the valve sleeve 20 also opens into the valve chamber 38, so that a pressure medium connection is created between the closure body guide 40 and this second valve opening 28.

[0028] In the closure body guide 40, a closure body 16 of the pressure-medium control valve 10 is guided so as to be able to slide axially, i.e. in the direction of the valve longitudinal axis L. The closure body 16 is a tappet having a cylindrical tappet stem 16.1 and a spherically curved tappet head 16.2 which is formed at one of the ends of the tappet stem 16.1. The tappet head 16.2 closes the control cross section 26.1 of the pressure-medium control valve 10, as shown in FIG. 1, while the closure body 16 is received so as to be able to slide in the closure body guide 40 with the end section of the tappet stem 16.1 facing the armature.

[0029] Approximately in the center of the cylindrical tappet stem 16.1, a radially extending axial stop 16.3 is formed. This axial stop 16.3 is configured as a surrounding annular protuberance with two parallel, opposite stop faces 16.4, 16.5. In FIG. 1, the first stop face 16.4 abuts against the end face of the cylinder section 16.3 of the armature 16. The second stop face 16.5 of the closure body 16, which faces away from the first stop face 16.4, is assigned to the inner surface of the armature capsule 44, by which the closure body 16 is bound to the armature 14 so as to be movable relative to it.

[0030] The armature capsule 44 forms a cup-shaped arresting device with a surrounding cup rim 44.1 and a cup bottom 44.2 which is formed in one piece with the cup rim 44.1. The cup bottom 44.2 is provided with a through-hole 44.3 through which the closure body 16 protrudes from the armature capsule 44 with its end section carrying the tappet head 16.2 and which directly cooperates with the control cross section 26.1 of the pressure medium valve 10. The dimensions of the through-hole 44.3 are larger than the outer dimensions of the tappet stem 16.1.

[0031] The armature capsule 44 is fixed in a force-locking manner via a cup rim 44.1 of the armature capsule 44 around the cylinder section 14.3 of the armature 14 in such a way that the closure body 16 accommodated inside the armature capsule 44 is movable in the direction of the valve longitudinal axis L relative to the armature 14. For this purpose, the armature capsule 44 is fitted onto the cylinder section 14.3 only to the extent that a gap is created between the end face of the armature 14 and the inner surface of the cup bottom 44.1, which gap is larger than the dimension of the axial stop 16.3 of the closure body 16 located in this gap.

[0032] 1 shows the described pressure-medium control valve 10 in the closed position, i.e. the pressure-medium connection between the first valve opening 26 and the second valve opening 28 is interrupted and the pressure-medium valve 10 is therefore not flowed through by pressure medium. For this purpose, due to the force of the valve spring 33, the armature 14 acts with its end face against the assigned first stop surface 16.4 on the axial stop 16.3 of the closure body 16 and presses the closure body 16 against the control cross section 26.1. The closure body 16 then moves in the armature capsule 44 towards the armature 14, so that the inner surface of the cup bottom 44.2 and the opposite second stop surface 16.5 of the closure body 16 no longer abut against each other but are now spaced apart from each other.

[0033] 2 shows the pressure medium control valve 10 according to FIG. 1 in the passing position. In this passing position, the armature 14 rests flush against the end face of the pole core 18 and the volume of the armature chamber 36 between the pole core 18 and the armature 14 is reduced to approximately zero. The stroke movement of the armature 14 towards the pole core 18 builds up a spring tension, by which the armature 14 is biased by the valve spring 33. Due to the axially fixed arrangement of the armature capsule 44 on the armature 14, the armature capsule 44 is subjected to the stroke movement. This leads to the cup bottom 44.2 of the armature capsule 44 engaging the opposite second stop surface 16.5 of the closure body 16. As the stroke movement of the armature 14 progresses, the armature capsule 44 lifts the closure body 16 from the first valve opening 26 of the pressure medium control valve 10, whereby the control cross section 26.1 is freed. With the opening of the control cross section 26.1, a pressure medium connection is provided between the first valve opening 26 and the second valve opening 28.

[0034] As shown in FIG. 2, the second stop surface 16.5 of the closure body 16 rests against the inner surface of the cup bottom 44.2, while the first stop surface 16.4 is raised from the end face of the armature 14. The closure body 16 assumes this position when a higher pressure level prevails in the second valve opening 28 and thus in the closure body guide 40 of the armature 14 than in the area of ​​the first valve opening 26. The pressure medium control valve 10 shown in FIG. 2 is thus passed through from the second valve opening 28 to the first valve opening 26, as indicated by the directional arrow R1. The closure body 16 is then relatively close to the control cross section 26.1 with its tappet head 16.2 and thus exerts a corresponding throttling effect on the pressure medium flow. This throttling effect limits the flow rate of the pressure medium in a given flow direction.

[0035] 3 shows the pressure-medium control valve 10 again in the through position, in which the closing body 16 rests with its axial stop 16.3 against the armature 14 or is raised from the inner surface of the cup bottom 44.2. The closing body 16 occupies this position when the pressure level at the first valve opening 26 is higher than the pressure level at the second valve opening 28 or in the closing body guide 40. The flow through the pressure-medium valve 10 accordingly runs in FIG. 3 from the first valve opening 26 to the second valve opening 28 (direction arrow R2) and thus in the opposite direction to the flow direction shown in FIG. 2.

[0036] In the valve position shown in Figure 3, the tappet head 16.2 of the closing body 16 is maximally separated from the control cross section 26.1 and therefore exerts only a slight throttling effect on the pressure medium flow through the pressure medium control valve 10. More pressure medium therefore flows through the pressure medium control valve 10 per unit of time in the valve position shown in Figure 3 than in the valve position shown in Figure 2. The pressure medium control valve 10 is thus designed to throttle the pressure medium flow differently between the first valve opening 26 and the second valve opening 28 depending on the flow direction R1, R2 of the pressure medium flow through the pressure medium control valve 10.

[0037] For switching from the blocking position shown in Fig. 1 to the passing position shown in Fig. 2 or 3, the pressure medium control valve 10 is equipped with a valve coil (not shown). This valve coil surrounds the cylindrical part of the valve housing 12 and generates a magnetic field when the valve coil is electrically operated. The pole core 18, the valve housing 12 and the armature 14 are made of a magnetically conductive material, so that the opposing end faces of the pole core 18 and the armature 14 are thus formed with the pole poles of this magnetic field. Between the two components, an attractive force is therefore generated by the energization of the magnetic coil, which attracts the described stroke movement of the armature 14 towards the pole core 18.

[0038] When the electrical control of the valve coil is cancelled, this attractive force is reduced so that the spring tension of the valve spring 33 is sufficient to return the armature 14 and the closure body 16, which is constrained by the armature 14, to the basic position shown in FIG. 1.

[0039] It is obvious that modifications or additions in the described embodiment are possible without the result thereby resulting from departing from the scope of protection defined by the claims.

[0040] In this connection it should be noted that the pressure-medium control valve 10 described is only shown as an example valve of the normally closed type. A normally open variant would also be feasible accordingly. Furthermore, it is not essential for the invention that the pressure-medium control valve 10 is equipped with a valve coil as actuator. [Explanation of symbols]

[0041] 10 Pressure medium control valve 12 Valve housing 14 Mover 14.1 Information Section 14.2 Transition Section 14.3 Cylinder Section 14.4 Valve spring housing 16 Closed body 16.1 Tappet stem 16.2 Tappet head 16.3 Axial Stops 16.4 First stop surface 16.5 Second stop surface 18 Pole Core 20 Valve sleeve 22 Shoulder 24 Annular Collar 26 First valve opening 26.1 Control Cross Section 28 Second valve opening 30 Ring Filter 32 Crimping ring 33 Valve spring 34 Longitudinal passage 36 Movable chamber 38 Valve chamber 40 Closed body guide section 42 Pressure medium passage 44 Movable capsule 44.1 Cup rim 44.2 Bottom of cup 44.3 Penetrations L Valve longitudinal axis R1 directional arrow, flow direction R2 directional arrow, flow direction

Claims

1. An electromechanically operable pressure medium control valve (10), comprising: a valve housing (12) in which an armature (14) drivable for stroke movement in the direction of a valve longitudinal axis (L) is movably accommodated; a pole core (18) for restricting the movement of the mover in one direction of movement; a valve sleeve (20) having a control cross section (26.1) formed therein; a closure body (16) which controls the pressure medium flow through said control cross section (26.1) and which can be operated by said armature (14); A pressure medium control valve (10) comprising: the pressure medium control valve (10) is designed to throttle the pressure medium flow differently between the first valve opening (26) and the second valve opening (28) depending on the flow direction (R1, R2) of the pressure medium flow through the pressure medium valve (10); Electromechanically actuable pressure medium control valve.

2. The closure body (16) is connected to the armature (14) by a restraining device (44); The restraining device (44) permits movement of the closure body (16) relative to the armature (14) in both forward and reverse stroke directions of the armature (14).

2. An electromechanically actuable pressure medium control valve according to claim 1 , characterized in that it comprises:

3. 3. The electromechanically operable pressure medium control valve according to claim 1 or 2, characterized in that the arresting device has a rotor capsule (44) fixed to the rotor, and in which the closure body (16) is slidably accommodated.

4. 4. An electromechanically operable pressure medium control valve according to claim 3, characterized in that the armature capsule (44) is cup-shaped, is firmly mounted on the outer periphery of the armature (14) by means of a cup edge (44.1) and has a cup bottom (44.2) with a through-hole (44.3).

5. 5. An electromechanically actuable pressure medium control valve according to claim 4, characterized in that the closure body (16) is a tappet having a tappet stem (16.1) and a tappet head (16.2), which protrudes through the opening (44.3) with an end section carrying the tappet head (16.2) and cooperates directly with the control cross section (26.1).

6. 6. An electromechanically actuable pressure medium control valve according to claim 5, characterized in that the tappet stem (16.1) is formed with a radially extending axial stop (16.3).

7. 7. An electromechanically actuable pressure medium control valve according to claim 6, characterized in that the axial stop (16.3) is a surrounding annular ridge with opposing stop faces (16.4, 16.5), a first stop face (16.4) facing one end face of the armature (14) and a second stop face (16.5) facing an area of ​​the armature capsule (44) surrounding the through-hole (44.3).

8. 8. An electromechanically operable pressure medium control valve according to claim 5, wherein the closure body (16) is slidably received with its end section of the tappet stem (16.1) facing the armature (14) in a closure body guide (40) on the armature (14).

9. 9. The electromechanically operable pressure-medium control valve according to claim 8, characterized in that the closing body guide (40) is connected in a pressure-medium conducting manner to one of the valve openings (26, 28) of the pressure-medium control valve (10) via a pressure-medium passage (42) formed in the armature (14).

10. The armature (14) is biased by a valve spring (33); and the pressure medium control valve (10) can be switched by an electrical operating control from a basic position, in which the pressure medium connection between the first valve opening (26) and the second valve opening (28) is interrupted, to a through position.

10. An electromechanically operable pressure medium control valve according to claim 1 , characterized in that it is

11. 11. An electromechanically operable pressure medium control valve according to claim 1, characterized in that the pressure medium control valve (10) controls a pressure medium connection between a main brake cylinder and a pedal stroke simulator in an electronically pressure-regulated vehicle brake system.

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