WO1999043523A1

WO1999043523A1 - Electromagnetic valve

Info

Publication number: WO1999043523A1
Application number: PCT/EP1999/001195
Authority: WO
Inventors: Diogenes Perez-Cuadro; Josef Lauer
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 1998-02-28
Filing date: 1999-02-24
Publication date: 1999-09-02

Abstract

The invention relates to an electromagnetic valve comprising a valve closing member (6) which is arranged in a valve housing (7) such that it can move in an axial manner and which controls the pressure medium connection in the valve housing (7). The valve closing member is placed on a magnetic armature (1). The electromagnetic valve also comprises a hydraulically operable valve piston (5) which is arranged in the valve housing (7) in such a way that it can move in an axial manner relative to the valve closing member (6). Said valve piston has an orifice borehole (4) placed in a row relative to a valve seat (14) which is to be closed by the valve closing member (6). The inventive valve has a first and second pressure medium connection (2, 3) which are arranged in the valve housing (7) and which are both connected to one another in the initial position of the valve piston (5) in a restriction-free manner. The orifice borehole (4) in the valve piston (5) which restricts the pressure medium stream between both pressure medium connections (2, 3) is closed by the valve closing member (6) when the magnetic armature (1) is in the initial non-electromagnetically energized position. In addition, an additional pressure medium channel (21) which is to be closed by the valve piston (5) is provided in the valve housing (7) for a restriction-free connection of both pressure medium connections (2, 3). Said channel is unblocked when the magnetic armature (1) is in the non-electromagnetically energized initial position.

Description

Solenoid valve

The invention relates to an electromagnetic valve according to the preamble of patent claim 1.

From DE 43 39 305 AI an electromagnetic valve has already emerged which is provided with an axially movable valve closing member which is attached to a magnet armature and which is arranged in the valve housing. Furthermore, a hydraulically actuated, axially movable valve piston is arranged in the valve housing. The valve piston has an orifice bore, which is located n row to a valve seat to be closed by the valve closing member. The valve housing also has a first and a second pressure medium connection, which are connected without throttles in the basic position of the valve piston and with a throttle in the electromagnetic valve switching position via the orifice bore.

Because the valve piston is guided in a liquid-tight housing fit and the hydraulic pressure application for the proper functioning of the valve piston is inevitably determined by the direction of flow through the valve, there are structural and functional restrictions which can be disadvantageous.

It is therefore the object of the present invention to provide an electromagnetic valve of the type mentioned in the introduction with the least possible functional and structural outlay. constantly improve.

This object is achieved according to the invention for an electromagnetic valve of the generic type with the characterizing features of patent claim 1.

Further features, advantages and possible uses of the invention will become apparent in the following from the description of several embodiments.

Show it:

1 is an overall view of a first expedient embodiment of the subject matter of the invention,

2 shows an alternative design of the valve piston essential for the subject matter of the invention with reference to FIG. 1,

3 shows a further functional configuration of the valve piston shown in FIG. 2,

Fig. 4 shows an electromagnetic valve in the non-excited

Basic position, in which the orifice bore in the valve piston is released,

5 shows a modification of the electromagnetic valve according to FIG. 4 with interchanged pressure medium connections.

1 shows a considerably enlarged illustration - 3 -

in a block-shaped housing 19 inserted solenoid valve, the valve housing 7 is designed in a cartridge design, which receives a push-shaped valve closing member 6, which is fastened by means of a press connection to a magnet armature 1, which is guided in a dome-shaped valve sleeve 20. Below the valve sleeve 7, which closes the valve housing 7, is located in an enlarged stepped bore of the valve housing 7, a valve piston 5 which is guided in it with play and which is provided with an orifice bore 4. The orifice bore 4 is in series with a valve seat 14 to be closed by the valve closing member 6. A circumference of the valve piston 5 is at least one generously dimensioned longitudinal groove 15, which, regardless of the position of the valve piston 5, provides a pressure medium connection between the one below and the one above the valve piston 5 guaranteed in the valve housing 7 located pressure medium space.

In the illustration shown, the magnet armature 1 is in the electromagnetically non-energized basic position, in which the orifice bore 4 in the valve piston 5 which throttles the pressure medium flow between the two pressure medium connections 2, 3 in the valve housing 7 is closed by the valve closing member 6. It is further provided according to the invention that for the throttle-free connection of the two pressure medium connections 2, 3, a further pressure medium passage 21 to be closed by the valve piston 5 is provided in the valve housing 7, which, according to the illustration, is released in the basic position of the electromagnetic valve shown.

In an electromagnetically excited position of the magnet - 4th

kers 1 is closed by the downward lifting movement of the valve closing member 6 not only the orifice bore 4, but also the further pressure medium passage 21, since the valve closing member 6 presses the upstream valve piston 5 onto the housing stage 13 delimiting the pressure medium passage 21 in the valve housing 7.

As soon as the electromagnetic excitation of the magnet armature 1 is interrupted by switching off the coil-side excitation current, the magnet armature return spring 9 clamped between the valve housing 7 and the magnet armature 9 presses the magnet armature 1 back into the basic position shown in the illustration, while the valve piston 5 acts under the action of a hydraulic closing force on the the further, throttle-free pressure medium passage 21 delimiting housing stage 13 remains pressure-tight. 1, the orifice bore 4 is now released from the valve closing member 6, so that pressure equalization between the pressure medium volume located below and above the valve piston 5 takes place exclusively via the orifice bore 4 from the direction of the first pressure medium connection 2 to the second pressure medium connection 3. In the present exemplary embodiment, pressure medium thus passes via the first pressure medium connection 2, which opens approximately axially into the valve housing 7, into the pressure medium space located below the longitudinal groove 15 and via the longitudinal groove 15 without throttling into the housing cavity located above the longitudinal groove 15, which, as previously described, passes through the aperture bore 4 establishes a hydraulic connection to the second pressure medium connection 3. Accordingly, there is the closure of the pressure medium passage 21 on the valve piston side and the hydraulic pressure 5 -

Sen the plate-shaped check valve 10 on the bypass bore 16 until a hydraulic pressure compensation ^¬ on the valve piston 5 is set only via the orifice bore 4 a connection of the two pressure medium connections.

After hydraulic pressure equalization between the pressure medium connections 2, 3 via the orifice bore 4, the further, throttle-free pressure medium passage 21 is released under the action of a pressure spring 8 resting on the valve piston 5, the valve piston 5 being supported on the valve closing member 6 in its original position and this closes the aperture 4. In a first embodiment, the compression spring 8 acting in the direction of the valve closing member 6 has a substantially lower pretensioning force than the magnet armature compression spring 9 which positions the magnet armature 1 in the basic position.

However, this interpretation depends essentially on the intended use of the valve design explained. It is therefore conceivable when using the above-mentioned valve for a slip-controlled brake system that the force of the compression spring for regulating the wheel brake pressure m of the front brake

8 is adapted to the biasing force of the armature compression spring 9 to a relatively small value of, for example, 5 Newtons, while by means of the aforementioned valve type for regulating the wheel brake pressure in the rear wheel brake, the force of the compression spring 8 is a multiple, for example 7 times the force of the above-mentioned Magnet armature spring

9 amounts. Both springs 8, 9 thus act counter to the magnet armature force in each case. It is also clear that in the application described for a wheel slip-controlled 6 -

Brake system during full braking with a correspondingly high release speed, the compression spring 8 is designed such that an undesirable, so-called closing and thus the unintentional closing of the pressure medium passage 26 is prevented by means of the valve piston 5. On the other hand, the magnet armature pressure adjusting spring 9 is able to position the magnet armature 1 in the basic position even under a fluid high pressure of approximately 300 bar.

From the drawing it can be seen that the magnet armature 1, the valve housing 7, the valve closing element 6, the valve piston 5, the magnet armature pressure adjusting spring 9 and the pressure spring 8 are arranged coaxially to one another in a largely rotationally symmetrical design. In contrast to the one-piece valve housing according to FIG. 4, in the initially available embodiment according to FIG. 1, the cartridge-shaped valve housing 7 in the area of the block-shaped receiving body is designed in two parts in order to appropriately mount the valve piston 5, the compression spring 8 and the rod filter 17 located below the valve piston 5 enable, which is used instead of an Rm filter shown in the following figures. Accordingly, the valve piston 5 is guided in the upper half of the housing along its jacket surface interrupted by the longitudinal groove 15, while the lower part of the valve housing accommodates the pressure medium connection 2, which approximately merges at an angle, and the pressure medium connection 3, which is approximately radially rounded. The rod filter 17 is accordingly arranged between the two pressure medium connections 2, 3 in the center of the valve axis in an extension of the stepped bore receiving the valve piston 5. The coaxially next to the pressure medium connection 2 on the input side The bypass bore 16, which encloses the valve housing 7, m connects to the plate-shaped check valve 10 arranged at the bottom of the valve housing 7, with a corresponding pressure reduction in the area of the plate filter 18, bypassing the valve piston 5 between the two pressure medium connections 2, 3. Instead of the plate-shaped check valve 10 shown in the figure, it is of course also possible to use a ball check valve which is known per se and which is likewise delimited coaxially to the bypass bore 16 by the plate filler 18 shown in the figure.

Another alternative to the arrangement of the compression spring 8 is given when the rod filter 17 shown is omitted. Instead of the rod filter 17, the compression spring 8 could then be used with a correspondingly smaller winding diameter m, the bore section of the rod filter 17 and, if necessary, the pressure medium connection 3 could be protected against contamination by means of an Rmg filter. In the present exemplary embodiment, the bypass bore 16 and the pressure medium connection 2 are directly connected to a pressure medium source, which corresponds to the brake pressure sensor when the electromagnetic valve is used for a wheel slip-controlled brake system. The pressure medium connection 3 directed approximately obliquely out of the valve housing 7 would be correspondingly connected to the wheel slip-controlled wheel brakes in the present application, whereby the proposed electromagnetic valve takes over the function of a de-energized, pressure-modulating inlet valve which forms a noise-reduced orifice valve by means of the structurally and functionally explained valve piston. As can be seen from FIG. 2, the flow through the solenoid valve can also take place in the opposite direction, so that in the latter application the brake pressure transmitter is connected to the pressure medium connection 3 and the wheel brake to the pressure medium connection 2. This results in a relatively simple drilling of the valve housing 7, since the pressure medium connection 3 opens into the valve housing 7 coaxially to the valve axis. 2 differs from FIG. 1 by the use of a valve plate 22 with a relatively large passage opening, which is also aligned coaxially to the valve axis. The valve piston 5 located between the valve plate 22 and the tappet-shaped valve closing member 6 is characterized by a particularly thin-walled, reduced-mass design, which can be produced inexpensively by deep drawing, pressing or plastic injection molding. Corresponding to the mechanical stress in the area of the valve closing member 6 and in the area of the valve plate 22, the sleeve-shaped valve piston part has a thick-walled insert part 11 which contains the orifice bore 4 and whose cap-shaped projection 12 is directed towards the through bore β. To calibrate the valve passage, a fixed orifice is also pressed in below the valve plate 22 or firmly connected to the valve plate 22, which can be designed as a cascade orifice if required. With regard to the function and the further construction essential to the invention, the essential features of the electromagnetic valve shown in FIG. 2 do not differ from the detailed description of the object according to FIG. 1, so that reference is made to FIG. 1 with regard to the features not mentioned in relation to FIG. 2 - 9

becomes .

Finally, with reference to the embodiment according to FIG. 2, the following description of the object according to FIG. 3 should indicate the possibility of using a check valve 10 inside the valve piston 5. 3 shows a partial illustration of the previously described insert part 11, which can be provided with a check valve 10 if desired or required. The check valve 10 is designed as a ball check valve, with the ball in a transverse channel

23 of the insert part 11 is inserted, which opens into the channel section of the orifice bore 4, so that in the electromagnetically closed switching position of the valve piston 5 the ball of the check valve 10 moves away from the valve seat stage of the transverse channel 23 as soon as the pressure medium connection shown in FIG. 2 3 sets a pressure drop in the direction of the pressure medium source. This ensures that even when the solenoid valve is closed from the direction of the pressure medium consumer via the pressure medium connection 2 and the closed orifice bore 4 into the transverse channel 23 pressure medium can flow, which can flow back via the check valve 10 in the direction of the pressure medium source and thus into the pressure medium connection 3.

FIG. 4 shows, while maintaining the details already known from FIG. 1, a constructive extension in the area of the valve piston 5, on which a sleeve-shaped cage is provided

24 is attached, which on the one hand securely guides the valve piston 5 in the housing stage 13, and on the other hand through the action of a spring 26 provided with a stop disk 25 - 10 -

the basic position of the valve enables the opening of the orifice bore 4. For this purpose, the stop disk 25 bears against a shoulder of the push-button-shaped valve closing element 6 under the action of the spring 26 supported on the valve piston 5. The inner shoulder of the cage 24 rests on the stop disk 25. The biasing force of the compression spring 8 which is supported between the valve piston 5 and the housing stage 13 is considerably smaller than the spring 26 which acts in the opposite direction in the cage 24. This embodiment has the advantage that at When the magnet armature 1 is excited, only a relatively small magnetic force is initially required to overcome the action of the compression spring 8 in order to close the relatively large pressure medium passage 21. Thereafter, only a slight increase in the magnetic force means that the spring 26 has to be overcome if the relatively small stroke of the valve closing element 6 is to be bridged in order to shut off the orifice bore 4. In the position of the valve piston 5 blocking the orifice bore 4, the stop disk 25 is then lifted off the inner shoulder of the cage 24 under the action of the valve closing member 6, while the spring 26 is compressed approximately to the block length by the stop disk 25. The electrical energy required for valve actuation is therefore low due to the design chosen.

While maintaining the details explained with regard to the embodiment according to FIG. 4 for the subsequent valve design according to FIG. 5, only the differences of the electromagnetic valve shown in FIG. 5 will therefore be discussed. - 11 -

The valve according to FIG. 5 differs from the valve according to FIG. 4 by the interchanged connection diagram of the pressure medium channels in the valve block and thus by the reverse flow through the pressure medium connections 2, 3. Consequently, a pressure medium sensor, for example, is included at the height of the valve piston 5 Brake pressure sensor for a wheel slip-controlled brake system, while below the valve piston 5 at the pressure medium passage 2 there is a connection for a pressure medium receiver, for example for a pump, which is connected to a slip-controlled wheel brake. This illustration shows that the electromagnetic valve described in FIG. 4 can be used universally without having to change the basic structure of the valve.

Furthermore, the solenoid valves described are characterized by the selected design by a low-noise, easily ventilated, flow-efficient and independent of hydraulic pressure fluctuations in operation.

12th

-references list

Magnetic armature, 3 pressure medium connection

Aperture hole

Valve piston

Valve closing member

Valve housing

compression spring

Magnet armature pressure spring 0 check valve 1 insert 2 projection 3 housing stage 4 valve seat 5 longitudinal groove 6 bypass bore 7 rod filter 8 plate filter 9 housing 0 valve sleeve 1 pressure medium passage 2 valve plate 3 cross channel 4 cage 5 stop disk

6 spring

Claims

- 13 patent claims

1.Electromagnetic valve, with a valve closing member arranged axially movably in a valve housing and controlling a pressure medium connection in the valve housing, which is attached to a magnet armature, and with a hydraulically actuated valve piston arranged axially movably to the valve closing member in the valve housing, which has an orifice bore which is in series with is located from the valve closing member to the closing valve seat, with a first and a second pressure medium connection in the valve housing, both of which are connected to each other without throttling in the basic position of the valve piston, characterized in that in the electromagnetically non-excited basic position of the magnet armature (1) the pressure medium flow between the two pressure medium connections (2, 3) throttling orifice bore (4) in the valve piston (5) from the valve closing element

(6) is closed or released, and that for the throttle-free connection of the two pressure medium connections (2, 3) a further pressure medium passage (21) to be closed by the valve piston (5) is provided in the valve housing (7), which in the electromagnetically non-energized basic position of the Magnet armature (1) is open.

2. Solenoid valve according to claim 1, characterized in that in the electromagnetically excited position of the armature (1), the orifice bore (4) and the further pressure medium passage (21) are closed.

3. Solenoid valve according to claim 1 or 2, characterized 14

characterized in that when the electromagnetic excitation of the magnet armature (1) is interrupted, the pressure medium connection between the two pressure medium connections (2, 3) is released via the orifice bore (4) by the valve closing member (6) and that the valve piston (5) acts under the action of a hydraulic closing force the other, throttle-free pressure medium passage (21) delimiting housing stage (13) is pressure medium tight.

4. Solenoid valve according to claim 3, characterized in that after a hydraulic pressure equalization between the pressure medium connections (2,3) via the orifice bore (4) of the valve piston (5) under the action of a compression spring (8) remains in its basic position in which the other , throttle-free pressure medium passage (21) is released and in which the orifice bore (4) is closed by placing the valve piston (5) on the valve closing member (6).

5. Solenoid valve according to claim 4, characterized in that the magnet armature (1) positioning in the basic position magnet armature compression spring (9) has a biasing force which is equal to or less than the force of the compression spring (8) in the direction of the valve closing member (6) is effective.

6. Electromagnetic valve according to claim 1, characterized in that the magnet armature (1), the valve housing (7), the valve closing member (6), the valve piston (5), 15 -

the magnet armature pressure spring (9) and the pressure spring (8) are aligned coaxially to each other.

7. Solenoid valve according to claim 1, characterized in that the valve piston (5) structurally above the further pressure medium passage (21) between the pressure spring in the valve housing (7)

(8) and the valve closing member (6) directed towards the orifice bore (4).

8. Solenoid valve according to claim 1, characterized in that the valve piston (5) by means of a sleeve-shaped cage (24) from the valve closing member (6) is guided spaced.

9. Solenoid valve according to claim 8, characterized in that between a remote from the valve piston (5) located inner shoulder of the cage (24) and the inner end face of the valve piston (5) with a stop disc (25) provided spring (26) is arranged is in a coaxial arrangement with the valve closing member (6).

10. Solenoid valve according to claim 9, characterized in that the biasing force of the spring (26) is greater than a compression spring (8) acting counter to it, which is arranged between the housing stage (13) and the valve piston (5).

11. Solenoid valve according to claim 9, characterized 16 -

shows that in the closed position of the valve closing member (6) the stop disc (25) is lifted off the inner shoulder of the cage (24).

12. Solenoid valve according to claim 8, characterized in that in the housing stage (13) a compression spring (8) is arranged which is in the opening direction of the

Valve piston (5) is supported on the cage (24).

13. Solenoid valve as claimed in claim 8, characterized in that opens at the level of the valve piston (5) in the housing step (13) a pressure medium connection (3), which i connected to a pressure-donor ^~ st, and that the pressure medium connection (3) via the Valve piston (5) leads to a pressure medium connection (2) which opens into the housing stage (13) below the valve piston (5) and is connected to a pressure medium receiver.

14. Electromagnetic valve according to claim 1, characterized in that the valve piston (5) takes a check valve (10) opening in the direction of the pressure medium source.

15. Electromagnetic valve according to claim 1, characterized in that the valve piston (5) is designed as a thin-walled, sleeve-shaped deep-drawn, pressed or plastic injection molded part, which is provided with a metallic, the orifice bore (4) receiving insert (11), the cap-shaped Projection (12) facing the housing stage (13).