WO2006077179A1

WO2006077179A1 - Electrically triggered valve

Info

Publication number: WO2006077179A1
Application number: PCT/EP2006/050065
Authority: WO
Inventors: Christoph Voss
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2005-01-21
Filing date: 2006-01-06
Publication date: 2006-07-27
Also published as: DE102005023547A1

Abstract

The invention relates to an electrically triggered valve whose axial operational air gap (XA) is located on the side of an armature (13) which faces away from the valve control piston (2), said armature cooperating with the valve control piston (2), such that the valve control piston (2) can be moved in the direction of the first valve control edge (3) by the actuator (1) when said actuator (1) is actuated. The valve control piston (2) is not hydraulically pressure-compensated by means of several inserted elements (8).

Description

Electrically controllable valve

The invention relates to an electrically controllable valve, in particular for use in an adjustable shock absorber, according to the preamble of patent claim 1.

From DE 196 24 898 C2 already electrically controllable valves for use in a shock absorber are known. These valves form a valve assembly consisting of a pre-stage and a main-stage valve. For the electrical control of the precursor valve, a solenoid is provided, which is connected for the variable adjustment of a valve opening cross-section in the valve housing with a valve piston whose valve sealing surfaces cooperate with a valve seat in the valve housing.

The object of the invention is to design a valve, in particular for use in a shock absorber, with as little effort as possible in such a way that a pressure-regulating and pressure-limiting function is ensured by using as simple as possible, functionally reliable means.

This object is achieved for a solenoid valve of the type indicated with the characterizing features of claim 1.

Other features, advantages and applications of the invention will become apparent from the following description of an embodiment of a valve in different operating positions. Show it :

Fig. 1 is a longitudinal section through a valve with the characteristics underlying the invention in a first pressure control position in which the excitation current corresponds to the maximum electrical drive current imax of the valve spool for actuating a valve spool, whereby the desired fluid flow flows through the valve under high fluid pressure, including a first valve opening cross-section Vl closed, an aperture Sl and a second valve opening cross-section V2 arranged upstream thereof is released,

2 shows the valve of Figure 1 in a further pressure control position, in which the excitation current corresponds to the minimum electrical drive current imin, whereby the desired fluid flow flows through the valve under low fluid pressure, including due to an intermediate position of the valve spool both valve port cross sections Vl, V2 are partially released,

FIG. 3 shows the valve according to FIG. 1 in a position in which the valve is not activated electrically (excitation current i = 0) or. is not controllable (fail-safe position), wherein for pressure and flow limitation to desired fixed values a first valve opening cross-section Vl released and a second valve opening cross-section V2 closed and a fluid flow passes through a parallel to the valve opening cross-section arranged aperture S2, FIG. 4 shows a characteristic field for clarification of the valve switching positions shown in FIG. 1-3 resulting fluid flows,

Fig. 5-12 the individual manufacturing steps for the valve.

By way of example, the basic structure of the valve according to the invention will be described by way of example with reference to FIG. 1.

It shows the Fig. 1 in longitudinal section an electrically actuated, monodirectionally operated valve, which is preferably used for controlling a shock absorber in a motor vehicle. The valve consists of an electric actuator 1, consisting of a designed in plunger type armature 13 and a valve spool 5. The armature 13 is connected via a stoßiförmigen extension 7 with the valve spool 2. The valve control piston 2 has substantially the contour of a valve spool, which is alternately applied with its lateral surface on two aligned in series with each other in the valve housing 4 valve control edges 3, 3 '. The two valve control edges 3, 3 'are formed by two transverse bores within a bushing 6 inserted in the valve housing 4, which are closed or released by two piston edges of the valve control piston 2. For the production of the first piston edge, the valve control piston 2 in the region of the first valve control edge 3 on its circumference a groove-shaped circumferential recess 15, while the second piston edge on the valve spool 2 is formed by a recess 15 'in the form of a V-shaped annular groove on the height of the second valve control edge 3 'and in the bushing 6 below the second valve control edge 3' provided inlet channel 11 extends. The latter recess 15 'is advantageously carried out so deep in the valve spool 2 that the fluid flow when passing through the inlet channel 11 is able to act hydraulically on a precisely defined in diameter, in the piston longitudinal direction in the recess 15 'extending insert body 8.

This one of several insert bodies 8 of the valve spool 2 advantageously contributes to the production of a state of the valve piston 2 which is not hydraulically pressure compensated for the perfect valve function. For this purpose, the valve control piston 2 has a first and a second piston section 2 a, 2 b, which are both connected to one another by the piston shaft in the region of a groove-shaped constriction 21. By means of the groove-shaped constriction 21, the two insert bodies 8 guided through the first piston section 2a of the valve control piston 2 can also be acted upon hydraulically in the desired manner.

For pressure-tight inlet resp. Passage of all insert body 8, the two piston portions 2a, 2b provided with through holes. The insert body 8 are supported with their protruding from the valve spool 2 ends of stops 12, which are spaced from the two end faces of the valve spool 2 in the valve housing 4 and. are fixed to the bushing 6.

The insert body 8 are preferably designed as metallic sealed in the through-holes cylindrical pins which remain under hydraulic application to the stops 12, while the valve spool 2 moves for the purpose of hydraulic pressure limiting or pressure control relative to the insert bodies 8.

Below, the advantageous structure of the bushing 6 will be explained: The inlet channel 11 penetrates as a transverse bore below the second valve control edge 3 ', the bushing 6. Between the inlet channel 11 and the second valve control edge 3', the bushing 6 a likewise as a transverse bore the bushing 6 penetrating aperture bore S2. Downstream of the second valve control edge 3 ', the first valve control edge 3 as well as the (first) diaphragm aperture S1 are in the form of a transverse bore in the bushing 6. At the lower end of the bush 6 is closed with a decker-shaped stop 12, on which the inserted into the lower piston portion 2b insert body 8 is supported.

An outlet channel 10 is located downstream of the first valve control edge 3 and downstream of the first diaphragm opening Sl above the bushing 6 in the valve housing 4.

The valve control piston 2 is designed as well as the armature 13 as precisely guided in the valve housing 4 plunger. In order to allow pressure equalization for the leakage flows along the metal in the valve housing 4 sealing lateral surfaces of the valve spool 2 and the armature 13, which consists of the valve spool 2, the extension 7 and the armature 13 integral valve assembly has a through hole 14 which extends longitudinally in the valve assembly extends.

Further, located between the armature 13 and the valve housing 4, a compression spring 9 in order to position the valve spool 2 in the electrically de-energized state at the second valve control edge 3 'can. In general, the sealing effect between the valve control edges 3, 3 'and the valve seat body 2 is produced exclusively by edge covering. As a result of the interaction of the valve control piston 2 with the valve control edges 3, 3 ', two variably adjustable valve opening cross-sections V 1, V 2 in the region of the bushing 6, with which a controlled fluid flow passes, are produced with electromagnetic excitation of the actuator 1.

The variable second valve opening cross section V2 is located upstream of the first valve opening cross section Vl in a series connection to the first valve opening cross section Vl, wherein both valve opening cross sections Vl, V2 are reciprocally open in proportion to one another by means of the valve control piston 2. to be closed.

In the region of the first valve opening cross-section Vl is the aperture Sl, the aperture cross-section is smaller than a provided in the region of the second valve opening cross section V2 aperture S2. The apertures Sl, S2 are introduced as bores in the longitudinal and transverse direction in the bushing 6. Through the diaphragm openings Sl, S2, the pressure increase p can be limited in a desired manner when the valve control piston 2 is attached to the first or second valve control edge 3, 3 'as a function of the volume flow Q (range I of the characteristic diagram depicted in FIG. 4).

In order to realize the characteristic field shown in Figure 4 and thus the desired function of the valve, the hydraulic applied surfaces of the valve spool 2 are interpreted differently taking into account the spring and magnetic force, which is why the hydraulically actuated piston surface A3 of the valve spool 2 in the region of the inlet channel 11th smaller than the piston area A2 of the valve control piston 2 in the region of the second valve control edge 3 'is to be dimensioned, on the other hand j edoch, however, the piston area A3 is greater than the piston area Al in the region of the first valve control edge third In order to be able to realize the desired piston area ratios Al <A3 <A2 in a manner which is as meaningful as possible in terms of manufacturing technology, maintaining a constant outside diameter on the valve control piston 2, the hydraulically actuated piston surfaces A1, A2, A3 are of the diameter designed to influence the piston surfaces Al, A2, A3 fixed insert bodies 8 penetrated. By a suitable choice of diameter of the insert body 8 can thus be adjusted precisely due to the effective area difference, the valve function shown in Figure 4. In the present embodiment, therefore, in the piston section 2a, two insert bodies 8 with the diameters d2, d3 and in the lower section 2b an insert body 8 with a diameter d4 are used, resulting in the following hydraulically acted upon active surfaces:

Al = (π / 4) (dl ² -d ^{2 2} -d 3 ² )

A2 = (π / 4) (dl ² )

A3 = (π / 4) (d4 ² ) where Al <A3 <A2.

The subject invention is advantageously designed such that an axial working air gap XA of the electric actuator 1 is disposed on the side facing away from the valve spool 2 side of a cooperating with the valve spool 2 armature 13, so that upon electrical actuation of the actuator 1, the valve spool 2 from the rest position at the second valve control edge 3 'in the direction of the first valve control edge 3 is movable.

The valve control piston 2 is hydraulically not pressure balanced due to the realized by the insert body 8 different active surfaces Al, A2, A3, so that taking into account the between the valve spool 2 and the Actuator 1 arranged compression spring 9, the map shown in Figure 4 comes about.

Another refinement or a desired influencing of the characteristic curves shown in FIG. 4 is achieved, if required, by a suitable special configuration of the geometry of the through bores in the bushing 6 provided for the inlet channel 11 and the control edges 3, 3 '

The hydraulic flow forces that occur during the flow through the valve are at least partially compensated by the sketched body geometry of the valve control piston 2 in the region of the two recesses 15, 15 '.

The following will now be exemplary with reference to FIGS. 1-4 the different valve positions along with the associated characteristics are shown.

FIG. 1 shows the valve with the features on which the invention is based in a first pressure control position, in which the excitation current corresponds to the maximum electrical drive current of the valve coil 5 mounted on the valve housing 4. As a result of the maximum excitation current imax the armature 13 holds the valve spool 2 against the action of the return spring 9 in register at the first valve control edge 3, so that initially passes exclusively through the aperture Sl, the fluid flow at high pressure p from the inlet channel 11 to the outlet channel 10. According to the flow pattern shown, the pressure medium thus passes from below into a first annular space 16 provided between the bushing 6 and the valve housing 4 and extending to the inlet channel 11. Since the inlet channel 11 is only partially covered by the lateral surface of the valve control piston 2, the pressure medium enters the V-shaped recess 15 ', where it is guided by the contour of the recess 15' in the direction of the unlocked second valve. tilsteuerkante 3 'advantageously deflected, after which the pressure medium again passes into a separate from the first annulus 16 second annulus 17, which allows a hydraulic connection to the first valve control edge 3 and the same in the bushing 6 arranged first aperture Sl. Since the valve control piston 2 with its lateral surface holds the first valve control edge 3 closed, the pressure medium passes exclusively via the first diaphragm opening Sl to the outlet channel 10, resulting in the characteristic curve profile shown in FIG. 4 in the characteristic field region I as a result of the action of the diaphragm aperture Sl. From a certain fluid flow Q through the valve, the pressure p is so great that the valve spool 2 due to its hydraulically applied end faces opposite to the action of the magnetic force due to the different sized active surfaces Al, A2, A3 moves down hydraulically and thus the recess 15 the first valve control edge 3 releases, whereby the further characteristic curve flattened in Figure 4 (map area II, characteristic imax).

Deviating from FIG. 1, FIG. 2 shows the valve in a control position in which the exciter current corresponds to the minimum electrical drive current of the valve coil 12. As a result of the minimum excitation current imin the armature 13 moves the valve spool 2 against the action of the compression spring 9 in a stable intermediate position in which both valve control edges 3, 3 'and thus their flow cross-sections Vl, V2 are released to a maximum flow between the inlet and Outlet channel 11, 10 to allow. In this pressure control position thus comes in the diagram of FIG. 4 illustrated pressure control characteristic imin, from which a shallow pressure increase with increasing volume flow Q can be seen. FIG. 3 shows the valve in a position in which the valve is not actuated electrically (excitation current i = 0) or. can not be controlled (fail-safe position). In this state, the valve control piston 2 closes due to the action of the compression spring 9, first, the second valve control edge 3 ', whereby the second valve opening V2 is virtually blocked up to the fluid flow through the aperture S2. As a result of the dazzle effect, the steep characteristic curve progression in region I shown in FIG. 4 initially results. As the fluid flow increases, the hydraulic pressure applied to the active surfaces of the valve control piston 2 increases to such an extent that the valve control piston 2 hydraulically releases the second valve control edge 3 'counter to the action of the compression spring 9, whereby the pressure / volume flow characteristic in FIG. 4 at the exciter current i = 0 has a flatter course in area II.

According to the diagram of FIG. 4 can be depending on the size of the excitation current i any set of curves by any number of positions of the valve spool 2 represent, of which explicitly three characteristic curves were exemplified with reference to Figures 1-3. The ordinate of the diagram shows in each case the pressure rise p and along the abscissa the volumetric flow Q is plotted. The steeper rise of the characteristic curve for i = imaχ compared with the characteristic curve for the condition i = 0 results from the fact that the diaphragm aperture Sl is smaller than the diaphragm aperture S2. For the condition that i = imin, the largest flow cross-sections V1, V2 result in the region of the two diaphragm openings S1, S2, whereby a particularly throttle-free and therefore flat characteristic curve illustrates the maximum flow through the valve. In the concrete use of the presented valve for a shock absorber, this means that with steeper characteristic curve, the damping effect increases. The advantageous assembly of the valve will be briefly described below with reference to FIGS. 5-12.

For this purpose, FIG. 5 firstly shows the valve housing 4 designed as a deep-drawn sleeve, in which the annular disk-shaped stop 12, which is likewise designed as a deep-drawn part, is inserted from below and is preferably pressed into a narrowed step section of the valve housing 4. From the top to the extended step portion of the valve housing 4, a retaining ring 18 is slipped over the valve sleeve 4, which serves to receive the provided for the magnetic drive 13 yoke ring. The retaining ring 18 is laser-welded to the valve housing 4 and the upper stop 12 in the region of the upper step portion.

FIG. 6 shows the valve control piston 2, which is already equipped with the two insert bodies 8 in the piston section 2a and is inserted with the bushing 6 from below with an assembly tool 22 into the valve housing 4. The facing away from the stop 12 faces of the pin-shaped adjusting 8 rest here initially under gravity on the adjacent piston portion 2b.

FIG. 7 shows the next assembly step, according to which the magnet armature 13 is pressed onto the extension 7 from above into the valve housing 4 until the top stop 12 contacts. The case effective reaction force is absorbed by the mounting tool 22.

8 shows the subsequent assembly of the compression spring 9 and the magnetic core 19 from above into the valve housing 4, wherein for adjusting the valve lift a mandrel 20 presses through the hole in the mounting tool 22 against the underside of the valve spool 2, before the magnetic core 19th is finally positioned in the valve sleeve 4 and welded.

Figure 9 shows the subsequent adjustment of the biasing force of the compression spring 9 by the spring force is measured during the displacement of an acting in the magnetic core 19 on the compression spring 9 adjusting sleeve 20 acting from below against the valve spool 2 setting mandrel.

After completion of the above-described adjustment steps, the assembly tool 22 is removed and inserted according to Figure 10 from below into the initially free passage opening of the valve spool 2 of the insert body 8 and secured against falling out by the ceiling-shaped stop 12 on the bushing 6.

11 shows the placement of the valve spool 5 with the yoke ring on the valve housing 4 until the yoke ring at the bottom of the retaining ring 18 rests. This is followed, finally, by welding of the yoke ring in the region of the collar on the retaining ring 18, to which reference is made to FIG.

LIST OF REFERENCE NUMBERS

1 actuator

2 valve control pistons

3 valve control edge 3 'valve control edge

4 valve housing

5 valve spool

6 bushing

7 extension

8 insert bodies

9 compression spring

10 outlet channel

11 inlet channel

12 stop

13 armature

14 through hole

15 recess 15 'recess

16 annulus

17 annulus

18 retaining ring

19 magnetic core

20 setting mandrel

21 constriction

22 assembly tool

23 adjusting sleeve

Vl first valve opening cross section V2 second valve opening cross-section

51 first aperture

52 second orifice XA Axial air gap

Claims

claims

1. Electrically controllable valve, in particular for a controllable shock absorber, with an actuator, an actuatable by the actuator valve spool, which can be applied either to a first or a second valve control edge in the valve housing, which are arranged in a series circuit to a first and a second Valve opening cross section by means of the valve spool reciprocally proportional to each other to change, characterized in that an axial working air gap (XA) of the electric actuator (1) on the side facing away from the valve spool (2) side of a with the valve spool (2) cooperating armature (13) is arranged in that, when the actuator (1) is actuated electrically, the valve control piston (2) can be moved by the actuator (1) to reduce the first valve opening cross-section (Vl) in the direction of the first valve control edge (3).

2. Valve according to claim 1, characterized in that the valve control piston (2) is designed as a valve piston with a constant outer diameter, which is not pressure-balanced hydraulically by one or more suitable hydraulically loadable insert body (8).

3. Valve according to claim 2, characterized in that for the preparation of the hydraulically not pressure-balanced state of the valve spool (2) has a first and a second piston portion (2a, 2b), that the two piston portions (2a, 2b) for pressure-tight passage of the insert body (8) are provided with through holes, wherein the Supported insert body (8) with their ends facing away from stops (12), which are fixed to the two end faces of the valve control piston (2) in the valve housing (4) and / or a bushing (6).

4. Valve according to claim 3, characterized in that the insert body (8) as at the stops (12) persisting cylindrical pins are to which the valve spool (2) for the purpose of hydraulic pressure limiting or pressure control is relatively displaceable.

5. Valve according to claim 4, characterized in that the insert body (8) as a result of in the valve housing (4) prevailing hydraulic pressure with their valve from the control spool (2) facing away from the stops (12) remain.

6. Valve according to one of the preceding claims, characterized in that in a parallel circuit to the first valve control edge (3) a first aperture (Sl) is provided, the aperture cross-section (Sl) is smaller than a parallel to the second valve control edge (3 ') arranged second Aperture (S2).

7. Valve according to one of the preceding claims, characterized in that the valve control piston (2) at its periphery in each case in the overlap region of the two valve control edges (3, 3 ') has a flow forces at least partially compensating body geometry, which in the form of a hollow-shaped in particular lenförmigen recess (15) and / or simplified as an annular groove is executed. Valve according to one of the preceding claims, characterized in that the two apertures

(Sl, S2) and the two valve control edges (3, 3 ') in a valve spool (2) leading bushing

(6) are arranged, wherein the bushing (6) is inserted in the valve housing (4) liquid-tight.