WO2006135319A1

WO2006135319A1 - Arrangement, device and method at a disturbance -eliminating valve for damper

Info

Publication number: WO2006135319A1
Application number: PCT/SE2006/000701
Authority: WO
Inventors: Lars Sönsteröd
Original assignee: öHLINS RACING AB
Priority date: 2005-06-14
Filing date: 2006-06-14
Publication date: 2006-12-21
Also published as: EP1893887A4; SE0501345L; EP1893887A1; US20090200125A1; EP1893887B1; US8136644B2; SE531736C2

Abstract

In an arrangement and device for a disturbance-eliminating valve or a method for eliminating disturbances in a valve in a vehicle, a partial step valve or pilot valve can be utilized that comprises a slide that can move in a space, in the medium, which slide is arranged to have an effect on a passage for the medium through the valve by means of guides that exert a valve pressure force on the slide that counteracts a force (Fl) exerted on the slide. By means of a part, the slide divides the space into a damping chamber and pilot pressure chamber (e and f respectively) arranged on the high pressure side or upstream of the piston that delimits the damping medium in two main chambers (19a, 19b). The pressure in the damping chamber is arranged, in a stationary control position of the slide, to assume a value that essentially corresponds to a pressure value in the pilot pressure chamber. In the event of an urged movement from the stationary control position, the slide is arranged to bring about a reduction in pressure over the said part. In the event of the said movement, the pressure in the damping chamber undergoes a change in value essentially proportional to the speed of movement of the body or the change in pressure and generates a damping force coinciding with the control force that counteracts the movements of the body and thereby brings about the disturbance elimination. Any admixture of gas in the medium is thereby prevented from changing the damping caused by the valve or from causing unwanted noises.

Description

Arrangement, device and method at a disturbance-eliminating valve for damper.

The present invention relates, among other things, to an arrangement with disturbance elimination for electronically-controlled shock absorbers for vehicles, for example shock absorbers, steering dampers, etc. The electronic control can be carried out by computer or actuator for so-called EC-function. The vehicles can be wheeled vehicles with two, three, four or more wheels. The invention can also be used for snow-scooters with runners, tracks, etc. The arrangement can have, among other things, control equipment that comprises movement-detecting sensors that detect the movements of wheels, runners, tracks, etc, and that send control signals to one or more dampers comprised in the arrangement in response to these movements. Each damper comprises a cylinder and a piston or piston device arranged inside this, which piston or piston device operates in a medium utilized by the damper (for example hydraulic oil with any additives) and divides the inner chamber of the cylinder into a first and second chamber compartment. The damper also comprises or interacts with one or more valves in the form of pilot valves or partial step valves that control the pressure of the medium in the chamber compartments and hence the damping carried out by the respective damper, for example in both directions, by means of the said control signals. Each valve comprises, in addition, at least one electrical coil that is connected or that can be connected to the control signals, and a part controlled by the coil when control signals are received, which part is able to move and preferably works with short strokes. By means of its movements, this part in turn affects a first piston that moves in a first space in, for example, a valve housing, against the action of a spring, which first piston divides the first space into a first and a second partial space. In a first functional state, the first piston assumes a longitudinally displaced position that causes a first flow of medium to pass from the damper's first chamber compartment, via the partial space below the first piston and on through a first side opening (port) arranged in the inner wall of the housing, to a first duct connected to the second chamber compartment. In a second functional state, the first piston assumes a longitudinally displaced position where a second flow of medium, unaffected by the first piston, passes from the first partial space to a second side opening (port) that is preferably to be found in the same housing and on to the second chamber compartment via a second duct and a non-return element arranged in this. When the second functional state is assumed, the first piston is arranged to be caused to move, by means of guide faces arranged on the valve piston and by guide faces in the housing that correspond to these, to a position in front of the first side opening where the first flow of medium is reduced and the second flow of medium is initiated due to an increase in pressure in the said partial space caused by the reduction in the first flow of medium and hence opening of the said element. In addition, the first piston assumes the position in front of the first side opening by means of the said spring and a reduction in pressure at the first side opening caused by the piston assuming the position alongside the first side opening. The first piston is arranged with passages between the partial spaces and there is thereby axial pressure relief in both the functional states.

The invention also relates to a device for dampers for vehicles and comprises or interacts with disturbance-eliminating valves in the form of partial step valves or pilot valves. The damper comprises a piston arranged in such a way that it can move in a cylinder or a blade that can rotate in a cylinder, which piston or blade divides the inner space in the cylinder, the valve housing, etc, into a first and a second chamber, with the chambers being connected together by one or more ducts via the said valve that has a valve slide and a valve piston arranged on this that can move in spaces arranged in the valve housing. The movements of the valve slide can be determined by a force that can be completely or partially initiated from an external actuator or a computer, for example a microcomputer. The movements can also be determined by a force that is determined by pressure acting upon the areas of the valve piston that can be affected by the said flow of the working medium between the first and second chambers and by a spring or spring function.

The invention also relates to a device for disturbance-eliminating valves in the form of partial step valves or pilot valves that comprise a valve slide that can move in a space in the medium, which valve slide is arranged to have an effect on a passage for the medium through the valve by means of guides that exert a pressure force on the slide and a pilot spring force, called a first force, in the opposite direction to an actuating force, called a second force, applied on the valve slide, whereby the body divides the space into a damping chamber and a pilot pressure chamber by means of a part.

The invention also relates to a method for eliminating disturbances caused by the admixture of gas in a damping medium in a partial step valve or pilot valve arranged in a vehicle.

The technology that has been used to date within the field is described in, for example, S9800775-0, S0400012-1, EP504624-A2 and EP400395-B1. The valves in question are described in these documents as pilot-controlled, with the damping of the pilot cone not being described in certain cases, but with the solenoid's armature being damped in its cylinder. In other cases, as in EP400395, the damping is described as a throttling between two chambers. Among other things, it is common to the known technical solutions that the damping arrangement is located on the low pressure side, that is downstream of the valve function that is to be damped.

The problem with the said valves is that their damping is based on the sum of hydraulic damping in the solenoid or in its vicinity, and friction. The shock absorbers or steering dampers, etc, that are used within the car industry do not usually have so-called gas-separating pistons, for which reason the hydraulic fluid becomes saturated with gas. After hard driving with such dampers, gas collects in pockets and closed spaces and the volume of gas increases the lower the pressure. This means that the damping that relates to valve functions on the low pressure side can be lost under the said circumstances. Remaining friction is insufficient to damp the valve function, which can cause oscillations with frequencies within the range 400-1500 Hz. This sound is particularly irritating to the human ear and is not acceptable to car users and car manufacturers. Increased friction has been tested and has been found not to solve the problem in a correct way. The invention is intended to solve this problem, among others.

There is also a desire for the valve in question, for example a proportional valve, to be able to be incorporated in a main valve in an integrated and space-saving way. The invention also solves this problem. The valve described above is able to operate silently and is completely unaffected by gas that is saturated in the oil in shock absorbers. In addition, the main stage of the valve can be provided with a double spring function that makes it possible to carry out very accurately set and low preloading with small variations in spite of the selection of a stiff spring constant. The whole valve can be assembled in sequence from one direction. In accordance with the invention, in the case with two functional states, the transitions between the different states must be able to take place without any specific actions or resetting having to be carried out, for example without the vehicle having to be stopped in order to carry out the transition. The arrangement and the device according to the invention can work with or can comprise dampers that are arranged with damping function in one or both directions. The dampers can consist of shock absorbers or steering dampers for vehicles between parts of the vehicle that can move in relation to each other.

The principal characteristic of an arrangement according to the invention is, among other things, that the first piston is located on a valve slide that can move in a longitudinal direction and that extends into the said partial space and into a second partial space in the housing that is connected to the said partial space. In addition, a control edge for the valve slide is located at the transition to the second partial space, while at the same time the part of the slide that extends into the additional space has an extension part upstream of the control edge with a second piston arranged on this that divides the second partial space into third and fourth partial spaces. These partial spaces divide up the area of action of the slide into a first part in association with the said seat or control edge and a second part on the underside of the second piston. In addition, the invention is characterized in that the second piston and an opposing inner guide face in the second partial space are arranged with a clearance between them that effects the elimination of disturbance by ensuring that the pressure differences that arise in the partial space in question (the cavity) at the second piston as a result of the speed of movement of the slide affect the second part of the area of action of the slide with a force that counteracts the movement. It is typical of the invention that the disturbance elimination also works when the partial space is filled with gas, due to the fact that, as early as during the pressure- increasing phase or pressure-reducing phase, a force arises that prevents movement, as the gas inside the partial space must first be compressed before movement of the slide can take place.

The valve thus works with damping on the high pressure side, that is upstream, which helps to solve the said problem.

Further developments of the concept of the invention are apparent from the subsidiary claims below that are associated with the arrangement.

The principal characteristic of a device according to the invention is, among other things that, at the high pressure side, that is upstream of the valve piston that was described in the introduction, there is a damping device that damps the movements of the valve piston irrespective of the state of the working medium, that is irrespective of the gas content in the medium.

Further developments of this concept of the invention are apparent from the subsidiary claims relating to the device in question.

The device according to the invention can also be said to be characterized in that, in a stationary control position of the body, the pressure in the damping chamber is arranged to assume a value that essentially corresponds to a pressure value in the pilot pressure chamber, in that, in the event of an urged movement from the stationary control position, the body is arranged to bring about a pressure difference at the said part and in that, in the event of the said movement, the pressure in the damping chamber undergoes a change in value that is essentially proportional to the speed of movement of the body and generates a damping force that coincides with the control force and that counteracts the movement of the body and thereby brings about the disturbance elimination, that can consist of preventing any admixture of gas in the medium affecting damping caused by the valve or preventing unwanted noises arising due to the admixture of gas. Depending upon which part of the damping process is being described, it is also possible to characterize the invention in that the damping force coinciding with the control force arises as soon as it is the case that the damping chamber is filled with gas in a pressure-increasing or pressure-reducing procedure for the reason that, on account of its compressibility, the gas in question cannot have a pressure-increasing or pressure-reducing effect on the area of action of the slide that is in the damping chamber.

By means of what is proposed in the above, a control function with control edge/seat/etc and piston/part/membrane/etc can be arranged on or in association with the slide or corresponding moving device. The function of the spring 6 can alternatively be provided by other devices that have a spring function. By stiff spring constant is meant values between 40-500 N/mm. The abovementioned problems are solved by the creation of a damping force that constitutes part of the first force and, at the same time, is on the high pressure side, upstream of the control edge, seat, etc.

The method according to the invention means that, in a first activated functional state, a second piston, arranged on the high pressure side or upstream of a valve piston that moves in the damping medium, is inserted into a space in a cylinder and divides this cylinder into an additional damping chamber, while at the same time it causes a change in pressure in the additional damping chamber. In a second functional state, called the inactivated or defective state, the damping medium flows more freely over the second piston and equalizes the pressure across the piston. The change in pressure thus generates an additional damping force that counteracts the movement of the valve slide irrespective of the admixture of gas in the damping medium in the first functional state but, however, not as much as in the second functional state.

Further developments of this concept of the invention are described in the subsidiary claims for the method in question. A currently proposed arrangement, device and method for an embodiment of the invention will be described below with reference to the attached drawings, in which

Figure 1 shows in outline a vertical section of an arrangement with a damped proportional valve with two functional states arranged to interact with a shock absorber for a vehicle in the form of a car, with the valve assuming an activated first functional state,

Figure Ia shows in outline and in horizontal section a blade damper that can be connected to the arrangement according to Figure 1,

Figure 2 shows in vertical section the valve according to Figure 1 in a second inactivated functional state,

Figure 3 shows in horizontal view the position function for the valve piston alongside a first side opening for a first flow of medium in the arrangement according to Figures 1-2,

Figure 4 shows in vertical section an embodiment of the valve with slots in the first functional state,

Figure 5 shows in vertical section an embodiment of the valve with slots in the second functional state,

Figure 6 shows in vertical section an embodiment of the valve with holes in the second functional state,

Figure 6a horizontal section that defines the area A3

Figure 6b vertical section that defines the area A2

Figure 7 shows in horizontal section an embodiment of the valve with slots in the second functional state, Figure 8 shows in vertical section how the pilot valve is integrated with the main valve in a dual spring configuration with spring holder,

Figure 9 shows in vertical section how the pilot valve is integrated with the main valve in a dual spring configuration with shim spring, and

Figures 10-12 show in vertical section a number of simplified variants of pilot valves with only one functional state.

Figure 1 shows the arrangement/valve with activated valve actuator and Figure 2 shows the arrangement/valve in activated state. The valve piston 1 is on the part that faces towards the actuator provided with a disk-shaped first piston 2, which is guided against the inner wall 3 of the pilot housing and makes contact with the actuator pin 4 in the plane 5 in an axial direction perpendicular to the direction of movement. The valve piston 1 of the pilot function is acted upon from one direction by a first force Fl from a spring 6 or a device exerting a spring function and the forces that result from the pressure in the chambers e and f and from a second direction by a second force F2 from the actuator 7 in the activated state. The pilot cone is normally located several hundredths from the control edge 8. In its extension, the valve piston 1 is provided with an extension part Ia and a second piston Ib, the guide face Ic of which has a clearance s2 to a cylinder Id that interacts with the control edge 8. The cylinder is provided with a communicating gap s2 and divides the function into an additional two chambers: a damping chamber e and a pilot pressure chamber f. When the valve piston is in the controlling position and is stationary, the pressure in the damping chamber is the same as in the pilot pressure chamber, whereby the first force Fl is created as the sum of the effect of the pilot pressure on the areas (If Ig). In the position to which the valve piston is forced by a movement or increase/reduction in pressure, the pressure in the damping chamber e is changed, however, almost or essentially in proportion to the speed of movement or increase/reduction in pressure of the pilot cone and thereby creates a damping force that always works against the direction of movement, that is counteracts the movement, in other words a damping or damping function is obtained. If there is gas in the damping chamber e, this makes no difference, as the said damping force is a part of the first force Fl and is located on the high pressure side, upstream of the control edge 8. The clearance s2 must be arranged with a narrow range and with a size that is in proportion to the selected diameter of the second piston Ib, for example from s=0.03 mm to s=0.05 mm for a piston diameter of 2.8 mm. That is, the ratio between size of clearance and piston diameter can be calculated as the quotient between s and d_kand the ratio can thus vary between 0.010 and 0.018.

In the second functional state, that is here called the inactivated state or defective state, according to Figure 2, the force of the spring 6 urges the pilot cone towards its opposite end position determined by the surface a. A number of holes 9 pass through the first piston 2 that provide communication between both sides of the first piston, space b and space c, which gives a total axial pressure relief on the pilot cone 1 in all positions and load conditions. In order to create additional control and pressure relief towards the surface a, in an embodiment, this can be provided with a surrounding chamber that has a number of holes or slots g that provide communication between the chamber b and the chamber towards the surface a, which additionally contributes to the said pressure relief also in the case when the disk rests against the surface a. At the same moment as the actuator of the valve piston 1 is deactivated, the first piston 2 moves towards its end position, defined by the surface a, and already before it has reached this position, the peripheral guide face 10 of its disk starts to close the radially-located port 11 with its flow ql l when the actuator is activated. A smooth transition to the second functional state is carried out towards a connection of a permanently set non-return element 12. The transition is smooth as a result of the gradually reduced flow ql 1 to ql 2 in the utilized side opening or the throttle 13 with its final partial flow ql2 in parallel with the second flow q22, a transition that is free of transients. The throttle is, for example, designed as a circular groove 14 into which the port 11 opens out. The return function from the second to the first functional state takes place in a corresponding way, by a gradually reducing flow q22 to a gradually increasing flow ql2, meaning that no special resetting function is required. In Figure 1, a space in the valve housing is indicated by 15. The said space is filled with the medium. An advantage is thus obtained as far as production technology is concerned, as the burring operation on the sensitive guide face is not required and due to the fact that no burrs interfere with the control of the slide disk. The diameter D and the height H of the groove determine the size of the throttle and hence of the partial flow ql2. This should preferably be precise and should be able to be repeated. The contact between the plane 5 and the plane a enables, however, the disk 2 to move radially, which it does when the safety function or the second functional state is applied, due to the fact that the disk is forced radially towards its closed position during its movement towards the outlet port 11 within the framework of the clearances S 1 and S2. In accordance with the above, the radial movement is extremely small or equal to the gap in question. Figure 1 also shows a second side opening 16 to a duct or space 17 provided with the non-return element 12. The ducts 11 and 17 each lead to a chamber compartment in a shock absorber 18 with cylinder 19 and piston 20. The chamber compartments above and below the piston 20 have the reference numerals 19a and 19b. The shock absorber can be arranged for a vehicle wheel 21, for example via a piston rod 20a. The cylinder 19 is connected to the chassis 22 of the vehicle. One or more sensors 23 are arranged on the wheel to detect and indicate the movements of the wheel relative to the chassis. A computer device 24 or computer function detects the sensor or sensors from one or more shock absorbers. The equipment sends control signals il to one or more coils on one or more solenoids or corresponding electronic units. The control signals bring about the forces F2 on the actuator pin or control device 4 of the solenoid part and hence the valve piston 1 in the valve. The detection signals from the sensor are given the reference numeral i2. The duct between the outlet of the valve 26a and the chamber compartment 19 is indicated by K2 and the duct between the space 17 and the first chamber compartment is shown by a broken line 28. The first piston 2 and the valve piston 1 assume the position shown in Figures 2 and 3 by means of the spring 6 and a reduction in pressure 27 that occurs across the opening 11, 13 when the second functional state is assumed in the event of the complete or partial cessation or loss of the signals.

The said reduction in pressure 27 creates flow conditions that attempt to pull the first piston in a radial direction towards the opening 11, 13 according to Figure 2. It has been found that the position can be repeated and that the piston assumes precisely or essentially the same position upon each assumption of the second functional state. This is possible without inclining the disk-shaped first piston 2 if the clearances si and s2 are made as equal to each other as possible or essentially the same size. The present construction differs from patent S0400012-1 in that the parts comprised in the pilot slide are guided at the points kl and k2 that are located a relatively large distance apart, for example approximately 8 mm, and in that the clearance between the first piston 2 and the inner wall 3 of the housing is made significantly smaller on account of said requirements concerning si and s2. The damping that is achieved by means of the piston Ib can be caused to cease, as it is not needed in the said second functional state, by a selection of a small value, for example approximately 0.1 mm, for the underlap/overlap ul in this position according to Figure 2. Figure 1 shows how the damping is activated by means of a relatively large value, for example approximately 1 mm, for the overlap ol.

Figure 3 shows that the area in the throttle 13 is Al = H*(Ds/2-Dd/2)*2 where Ds = the diameter of the circular groove 14, H = the height of the circular groove and Ds = the diameter of the first piston 2. Ds, Dd and H are preferably selected around 9.8, 10.1 and 0.6 mm. The valve piston 1 according to the above is preferably constructed so that the surfaces 5, 8 and a are flat and perpendicular (radially directed) to the direction of movement (axially directed). The first piston 2 can always assume an unambiguous, well-defined and particular position on account of the clearance s2 that should preferably be the same size as the clearance si in order to allow a narrow range of the partial flow ql2, which thereby constitutes an accurately determined leakage flow determined by, for example, the diameter Ds.

In the second functional state, according to Figures 5 and 6b, the partial flow ql2 can also be accurately determined by the breadth B and height H2 of the groove 42 by means of the area A2=H2*B*2 or, as in Figures 6 and 6b, by means of only the hole 43 with the hole area A3=π/4*d^Λ2. In both these cases, Ds is so large that no reduction in pressure arises in this zone. The measurements Ds, B and H are preferably selected around 12.8, 0.2 and 0.5 mm respectively. The first functional state is shown in Figure 4, showing the normal functional principle with its first flow ql 1.

Figures 5, 6 and 7 show the second functional state, showing the functional principle with a first partial flow ql2 and a second partial flow q22.

Figure 8 shows a unit as far as production technology is concerned, with the valve in its entirety, which unit can be assembled from one direction, due to the fact that the pilot housing 30 constitutes a separate component that can be assembled from the same direction as a main cone 31 and a main seat 32. An innovation as far as functional technology is concerned is that the main cone of the valve has been provided with two springs connected in series, "dual springs", one stiff spring 33 and one weak spring 34 adjusted so that the pre-stressing of the main cone is low and precisely determined by the weak spring, preferably selected around F=O.5+0.4 N. The required stiffness is in a range between Kl =40-500 N/mm for the main function that is determined by the stiff spring. The weak spring, with spring constant preferably around K2=l N/mm, is preferably selected to work with an extremely short stroke, preferably around x=0.035 mm with small permitted variation +0.03 mm, which in turn is achieved by a suitable choice of shims 35. In the case shown, the springs are guided and held by a spring holder 36.

Figure 9 shows the described function implemented by means of a flat thin spacer 37 with a thickness t of preferably approximately 0.4 mm and a thin shim spring 38 with a thickness t of preferably approximately 0.1 mm. This construction is only one example, and the components 37 and 38 can, of course, be designed as a single shim spring connected in series with the main spring.

Both Figure 8 and Figure 9 show that the pilot function 39 has an integrated position inside the main spring 33 in the center, which means that the total valve concept can be made compact.

Figures 10, 11 and 12 show three embodiments of the pilot valve 40 that is described above, utilizing a valve piston 1 without safety function 41. Simplified embodiments are possible, and accordingly the safety function can be removed in the described pilot valve design.

In Figure Ia, the damper, for example the shock absorber, with cylinder and piston, has been replaced by a damper, for example a steering damper, in the form of a blade damper with housing 43 and blade 44. The housing is designed with ducts 45 that make it possible to connect the connections 26', 28' and 28a' to the first and second chamber compartments 46, 47 of the damper.

The invention also relates to a method for eliminating disturbances caused by the admixture of gas in a damping medium in a partial step valve or pilot valve arranged in a vehicle, where the valve comprises a valve slide that can move in a space (b, c, f) in the medium, arranged in ducts (Kl, K2) between a first (19a) and a second (19b) chamber filled with damping medium and constructed of a valve piston (1), an extension part (Ia), a second piston (Ib) and a first piston (2). The method according to the invention means that, in a first activated functional state, the second piston (Ib) that is arranged on the high pressure side or upstream of the valve piston (1) is inserted into a space in a cylinder (Id) and divides this cylinder (Id) into an additional damping chamber (e), while at the same time it causes a change in pressure in the additional damping chamber (e). In a second functional state, called the inactivated or defective state, the damping medium flows more freely over the second piston (Ib) and equalizes the pressure across the piston (Ib).

The method thus affects the flow of working medium over the second piston (Ib) and brings about an additional damping force applied on the slide which coincides with a first force (Fl) determined by pressure acting on areas (If, Ig) of the valve piston (1) arranged on the valve slide. The first force (Fl) is opposed to a second force (F2) which can be completely or partially initiated by an external controllable actuator (7) or a computer function. The extension part (Ia) and the second piston (Ib) work in a fourth partial space (f), on the high pressure side, that is upstream, of the valve piston

(1) so that the second piston (Ib) divides the cylinder (Id) into the damping chamber

(e) that is separated from the fourth partial space (f). In its first functional state, the second piston (Ib) is also arranged with a clearance (s2) and an overlap (ol) in the cylinder (Id) so that, in a stationary control position for the valve slide, the damping medium is allowed to flow via the overlap (ol) through this clearance (s2) in such a way that the pressure in the damping chamber (e) assumes a value that essentially corresponds to a pressure value in the fourth partial space (f). The size of the clearance (s2) in relation to the diameter of the second piston (Ib) is selected in such a way that, in the event of an urged movement of the valve slide from the stationary control position, the pressure in the damping chamber (e) undergoes a value change that is essentially proportional to the speed of movement of the valve slide and generates the damping force coinciding with the first force (Fl) that counteracts the movement of the valve slide and thereby brings about the disturbance elimination.

Names of components:

1 Valve piston, valve body, cone, pilot cone

I a Extension part, pin Ib Second piston, piston Ic Guide face

Id Cylinder

Ie Openings

If Area, second partial area

Ig Area, first partial area 2 First piston, valve slide

3 Inner wall

4 Actuator pin, (the actuator's pin, pin)

5 Plane

6 Spring, pilot spring 7 Actuator

8 Control edge, seat, pilot seat

9 Hole, passage

10 Guide face, (peripheral part of the disk)

I 1 Port, duct, opening 12 Non-return element, element, body

13 Opening, side opening, throttle

14 Circular groove

15 Space in the valve housing

16 Second side opening 17 Second duct, duct, space

18 Shock absorber

19 Cylinder, chamber compartment 19a First chamber, chamber compartment 19b Second chamber, chamber compartment 20 Piston

21 Vehicle wheel

22 Chassis

23 Sensor 24 Control equipment, computer equipment

25 Electrical coil

26 Inlet, inlet of the main valve 26a Main valve 26b Pilot valve

27 Reduction in pressure

28 Duct

29 Housing

30 Pilot housing 31 Main cone

32 Main seat

33 Main spring, stiff spring

34 Weak spring, spring

35 Shim, thin spacer 36 Spring holder

37 Thin spacer

38 Pilot function, pilot valve

39 Pilot valve

40 Piston without safety function 41 Hole, slot

43. Blade damper housing

44. Blade

45. Duct

46. First chamber compartment 47. Second chamber compartment

Other names of components and other terms in the text a contact surface b second partial space c first partial space d opening e third partial space, damping chamber f fourth partial space, pilot pressure chamber s slot Kl Duct

K2 Duct kl contact surface k2 contact surface ql 1 first flow ql2 partial flow, leakage flow, reduced flow q22 second flow

11 control signal, control current

12 signal from sensor Fl first force, operating force

F2 second force, actuating force ul underlap ol overlap si first clearance s2 second clearance

Al first leakage area

A2 second leakage area

A3 third leakage area

H height B breadth

D diameter d diameter

The combined part consisting of a valve piston (1), an extension part (Ia), a second piston (Ib) and a first piston (2) is called the valve slide.

The pilot pressure acts on the regulator area of the said valve slide, which regulator area is divided into two areas (If, Ig) that have been called the areas of action of the slide.

The invention is not limited to the embodiments described above, but can be modified within the framework of the following patent claims and concept of the invention.

Claims

1. An arrangement with disturbance elimination for dampers for vehicles, which dampers are controlled electronically, for example controlled by computer or EC-controlled, with control equipment (24) that comprises movement-detecting sensors and in response to these initiates control signals (il) to one or more dampers, each damper comprising a cylinder (19) and a piston (20) arranged in this that works in a medium (31) utilized by the damper and that divides the inner chamber of the cylinder into a first and second chamber compartment (19a, 19b), which arrangement comprises or interacts with one or more valves (26b) in the form of pilot valves or partial step valves that control the pressure of the medium in the chamber compartments and hence the damping carried out by the damper, for example in both directions, by means of the said control signals, with each valve comprising at least one electrical coil (25) that is connected or that can be connected to the control signals, and a part controlled by the coil when control signals are received, which part is able to move (4) and preferably works with short strokes, and that in turn, by means of its movements, affects a first piston (2) that moves in a first space in a valve housing, against the action of a spring (6), which first piston (2) divides the first space into first and second partial spaces (c, b) and, in a first functional state, assumes longitudinally displaced positions that cause a first flow of medium (ql 1) to pass from the damper's first chamber compartment, via the partial space (c) below the first piston (2) and on through a first side opening (11, 13) arranged in the inner wall (3) of the housing, to a first duct (11) connected to the second chamber compartment and, in a second functional state, assumes a longitudinally displaced position where a second flow of medium (q22), unaffected by the first piston, passes from the first partial space (c) to a second side opening (16), that is arranged in the housing (29) and that is preferably opposite to the first side opening (13) in the housing, and on to the second chamber compartment (19b) via a second duct (17) and a non-return element (12) arranged in this, in addition to which, when the second functional state is assumed, the first piston is arranged to be caused to move, by means of guide faces (10) arranged on the first piston (2) and the inner wall (3) in the housing corresponding to these, to a position in front of the first side opening (13) where the first flow of medium (ql 1) is reduced and the second flow of medium (q22) is initiated due to an increase in pressure in the said partial spaces (c, b) caused by a reduction in the first flow of medium and hence opening of the element (12), and where the first piston assumes the position in front of the first side opening by means of the said spring and a reduction in pressure at the first side opening caused by the piston assuming the position alongside the first side opening, and the first piston (2) is arranged with passages (9) between the partial spaces (c, b) and there is thereby axial pressure relief in both the said functional states, characterized in that the first piston (2) is located on a valve slide (2, 1, Ia, Ib) that can move in a longitudinal direction and that extends into the said partial spaces and into a second partial space in the housing that is connected to the said partial spaces (b, c), in that a control edge (8) for the valve slide (2, 1, Ia, Ib) is located at the transition to the second partial space, in that the valve slide (2, 1, Ia, Ib) has an extension part (Ia) located upstream of the control edge on its part that extends into the additional space and has a second piston (Ib) arranged on this that divides the second partial space into third and fourth partial spaces (e and f) that divide up the area of action of the slide into a first partial area (Ig) in association with the said control edge and a second partial area (If) on the under surface of the second piston, and in that the second piston is designed with a peripheral guide face (Ic) that opposes the cylinder wall (Id) in the second via a clearance (s2), and in that this clearance is arranged to effect the disturbance elimination by bringing about changes in the pressure that arises in the partial space (e) associated with the second piston as a result of the speed of movement or increase/reduction in pressure on/over the slide by means of the second partial area (If) of the area of action of the slide affecting the force (Fl) in a direction that counteracts the movement.

2. The arrangement as claimed in claim 1, characterized in that the slide is arranged to carry out essentially longitudinal displacement movements and small radial clearances (si and s2) of preferably essentially the same size.

3. The arrangement as claimed in claim 1 or 2, characterized in that the said force brings about a damping function and essentially prevents any admixture of gas in the medium from affecting the damping.

4. The arrangement as claimed in claim 1, 2 or 3, characterized in that there is reduction of noise from the shock absorbers due to the fact that any admixture of gas in the medium is prevented from affecting the damping.

5. The arrangement as claimed in any one of claims 1-4, characterized in that the reduced second flow (ql2) is arranged to be able to be calibrated, in the second functional state, in holes (42), slots or passages.

6. The arrangement as claimed in any one of claims 1-5, characterized in that the housing/pilot valve (26a, 29, 39, 40) has openings (Ie) via which the first and second flows are able to pass, in that, in the first functional state, the second piston (Ib) is positioned in such a way in relation to the openings that an overlap (ol) that is created is sufficiently large to bring about damping, while, in the second functional state, the overlap has a value or has changed to an underlap (ul) or a smaller overlap (ol) of such a size that the damping is inactive or is greatly reduced, in order to make possible rapid changes or transitions between the two functional states.

7. The arrangement as claimed in any one of claims 1-6, characterized in that it comprises a pilot valve (30, 39) incorporated in a main valve that means that a large part of its function (30) takes place inside the construction of the main valve, for example inside its main spring (33), whereby a compact design is obtained.

8. A device for a damper for vehicles where the damper has a piston device (20), rotating blade device, etc, that can move in a cylinder (19) or in a housing, which piston device (20), rotating blade device, etc, divides the inner space in the cylinder, housing, etc, into first and second chambers (19a, 19b) interconnected by one or more ducts (Kl, K2), with the device comprising a disturbance- eliminating valve (26b) in the form of a partial step valve or pilot valve, arranged in the ducts (Kl, K2), where the valve (26b) comprises a valve slide consisting of a valve piston (1), an extension part (Ia), a second piston (Ib) and a first piston (2), with the first piston (2) being arranged on the valve piston (1) and being able to move in first and second partial spaces (c, b) arranged in the housing (29) of the valve, with the displacement movements of the first piston (2) being able to be determined by a second force (F2) that can be initiated completely or partially by an external controllable actuator (7) or a computer function, and by a first force (Fl) that is affected by the flow of working medium between the first (19a) and second (19b) chambers and is determined by pressure acting upon areas (If, Ig) of the valve piston (1) arranged in a fourth partial space (f) inside a pilot housing (30) arranged in association with the housing (29), characterized in that the extension part (Ia) and the second piston (Ib) are arranged in the fourth partial space (f), on the high pressure side, that is upstream, of the valve piston (1), with the second piston (Ib) dividing a cylinder (Id) arranged in association with the pilot housing (30) into a damping pressure chamber (e) separated from the fourth partial space (f), where changes in pressure in the damping pressure chamber (e) caused by the movement of the valve slide or increases/reductions in pressure across the valve slide create a damping force irrespective of the volume of gas in the damper, as the said damping force is a part of the first force Fl that always acts against the direction of movement and damps the movements of the valve piston (1).

9. The device as claimed in claim 8, characterized in that the guide face (Ic) of the damping device (Ia, Ib, Id) is arranged with a clearance (s2) to the cylinder (Id) which is provided with openings (Ie) arranged in association with the pilot housing (30).

10. The device as claimed in claim 9, characterized in that the size of the clearance (s2) in relation to the diameter of the second piston (Ib) is selected to be such that, in the event of an urged movement of the valve slide from the stationary control position, the pressure in the damping chamber (e) undergoes a change in value that is essentially proportional to the speed of movement of the valve slide, for example, the ratio between the size of the clearance (s2) and the diameter of the second piston (Ib) is between 0.010 and 0.018.

11. The device as claimed in claim 9 or 10, characterized in that the second piston (Ib) is located in such a way in relation to the openings (Ie) that, in a first functional state, when the actuator (7) or the computer arrangement is activated, the second piston (Ib) is positioned so that it is inserted in the cylinder (Id) with an overlap (ol) in relation to the openings (Ie) that is such that the movements of the second piston (Ib) are damped only in this functional state and in that, in a second functional state with an inactivated or defective system, the spring (6) moves the valve slide towards its opposite end position defined by a surface (a) in such a way that the overlap (ol) of the second piston (Ib) in relation to the openings (Ie) has a value or has changed to an underlap (ul) or a smaller overlap (ol) of such a size that the damping is inactive or greatly reduced, in order to make possible rapid changes or transitions between the two functional states.

12. The device as claimed in any one of claims 8-11, characterized in that the control signals to the controllable actuator (7) or the computer are in response to sensors (23) arranged to detect and indicate movements of the wheel, runner, track, etc, in relation to the chassis of the vehicle.

13. The device as claimed in any one of claims 8-12, characterized in that the valve piston (1) can move in a radial direction in relation to the pilot housing (30) and where the axial position of the valve piston (1) is determined by the actuator (7) or the computer function and by spring devices (33, 6).

14. The device as claimed in claim 13, characterized in that when a second functional state, that is an inactivated or defective state, arises, the second piston (2) covers a duct (11) and limits a first flow (ql 1) of working medium between the first (19a) and second (19b) chamber, so that a non-return element (12) connected to a duct (17) is opened by the difference in pressure that arises and the main flow (ql 1) of the working medium through the duct (11) is divided into flows (ql2 and q22).

15. The device as claimed in claim 14, characterized in that a displacement of the first piston (2) results in the main flow (qll) in the duct (11) gradually becoming a final flow (ql2) that flows in parallel with the flow (q22) in the duct (17) so that no transients arise.

16. A method for eliminating disturbances caused by the admixture of gas in a damping medium in a partial step valve or pilot valve arranged in a vehicle, where the valve comprises a valve slide that can move in a space (b, c, f) in the medium, arranged in ducts (Kl, K2) between a first (19a) and a second (19b) chamber filled with damping medium and that is composed of at least a valve piston (1) and a second piston (Ib), characterized in that, in a first activated functional state, the second piston (Ib) arranged on the high pressure side or upstream of the valve piston (1) is inserted into a space in a cylinder (Id) and divides this cylinder (Id) into an additional damping chamber (e) while, at the same time, it brings about a change in pressure in the additional damping chamber (e) and, in a second functional state, called the inactivated or defective state, damping medium flows relatively freely or completely freely over the second piston (Ib) and equalizes the pressure across the piston (Ib).

17. The method as claimed in claim 16 characterized in that when the flow of working medium over the second piston (Ib) is affected, an additional damping force is achieved applied on the slide, which coincides with a first force (Fl) determined by pressure acting on areas (If, Ig) of the valve piston (1) arranged on the valve slide, where the first force (Fl) opposes a second force (F2) which is completely or partially initiated by an external controllable actuator (7) or a computer function.

18. The method as claimed in claim 16 or 17 characterized in that the second piston (Ib) is arranged on an extension part (Ia) and these operate in a fourth partial space (f) on the high pressure side, that is upstream, of the valve piston (1) so that the second piston (Ib) divides the cylinder (Id) into the damping chamber (e), that is thus separated from the fourth partial space (f).

19. The method as claimed in claim 18 characterized in that, in its first functional state, the second piston (Ib) is arranged in the cylinder (Id) with a clearance (s2) and an overlap (ol), so that when the valve slide is in a stationary control position, the damping medium flows via the overlap (ol) through this clearance (s2) which results in the pressure in the damping chamber (e) assuming a value that essentially corresponds to a pressure value in the fourth partial space (f) and, in the event of an urged movement of the valve slide from the stationary control position, the pressure in the damping chamber (e) undergoes a change in value that is essentially proportional to the speed of movement of the valve slide or the level of increase/reduction in pressure, which generates the damping force coinciding with the first force (Fl) that counteracts the movement of the valve slide and thereby brings about the disturbance elimination.