Abstract
Valve arrangement for a shock absorber is described, comprising a valve housing (2) having a first (7) and a second port (8), a pilot chamber (3) being in fluid communication with the first (7) and/or second port (8), wherein a pilot pressure (Pp) is defined by a hydraulic pressure in the pilot chamber (3). The arrangement further comprises a main valve member (4) being axially movably arranged in the valve housing (2) and being arranged to interact with a main valve seat member (9) in order to restrict a main fluid flow between the first (7) and second ports (8) in response to the pilot pressure (Pp) acting on the main valve member (4). Moreover, the main valve seat member (9) is movable between a first compression stroke position and a second rebound stroke position so that, during the compression stroke, the main fluid flow is restricted at a first restriction (R1) and a cooperating serially arranged second restriction (R2), and during the rebound stroke, the main fluid flow is restricted at a third restriction (R3) and a cooperating serially arranged fourth restriction (R4).
Claims
1. A valve arrangement for a shock absorber, said valve arrangement comprising: a valve housing comprising a first and a second port; a pilot chamber being in fluid communication with said first and/or second port, wherein a pilot pressure is defined by a hydraulic pressure in said pilot chamber; and a main valve member being axially movably arranged in said valve housing and being arranged to interact with a main valve seat member in order to restrict a main fluid flow between said first and second ports in response to said pilot pressure acting on said main valve member; wherein the main valve seat member is movable between a first compression stroke position and a second rebound stroke position so that, during the compression stroke, the main fluid flow is restricted at a first restriction comprising an orifice and a cooperating serially arranged second restriction comprising an orifice, and, during the rebound stroke, the main fluid flow is restricted at a third restriction comprising an orifice and a cooperating serially arranged fourth restriction comprising an orifice; and wherein the orifice of said first restriction is controlled by means of the axial position of the main valve member relative to the valve housing.
2. The valve arrangement according to claim 1, wherein the first restriction is arranged upstream relative the second restriction, in view of the compression fluid flow direction and the first restriction has a smaller orifice than the second restriction's orifice in at least an initial stroke and when being at least partly opened.
3. The valve arrangement according to claim 1, wherein the third restriction is arranged upstream relative the fourth restriction, in view of the rebound fluid flow direction, and wherein the third restriction has a smaller orifice than the fourth restriction's orifice in at least an initial stroke and when being at least partly opened.
4. The valve arrangement according to claim 1, comprising a fifth restriction being arranged in series with the second restriction.
5. The valve arrangement according to claim 4, wherein the fifth restriction has a constant orifice being independent of the axial position of the main valve member relative the valve housing.
6. The valve arrangement according to claim 1, comprising a sixth restriction being arranged in series with the fourth restriction.
7. The valve arrangement according to claim 6, wherein the sixth restriction has a constant orifice being independent of the axial position of the main valve member relative the valve housing.
8. The valve arrangement according to claim 6, wherein said main valve member further comprises a geometrically defined circumferential aperture having a radial inner wall and a radial outer wall, wherein the radial inner wall forms a part of the fourth restriction and the radial outer wall forms a part of the third restriction, and wherein said sixth restriction is at least one opening into said circumferential aperture in said main valve member.
9. The valve arrangement according to claim 1, wherein said main valve member further comprises a geometrically defined circumferential aperture having a radial inner wall and a radial outer wall, wherein the radial inner wall forms a part of the fourth restriction and the radial outer wall forms a part of the third restriction.
10. The valve arrangement according to claim 1, wherein the orifice of the third restriction is a circumferential orifice, the valve arrangement further comprising a geometrically defined circumferential blocking means for blocking at least a part of the circumferential orifice of the third restriction, so that the third restriction has a smaller orifice than the fourth restriction's orifice in at least an initial stroke and being at least partly opened.
11. The valve arrangement according to claim 10, wherein said blocking means is an axially extending wall blocking an envelope outer surface of said radial outer wall.
12. The valve arrangement according to claim 10, wherein said blocking means forms an integral part of the valve seat member.
13. The valve arrangement according to claim 10, wherein said blocking means constitute a separate blocking member.
14. The valve arrangement according to claim 1, wherein at least one of the orifices of said second restriction, third restriction and/or fourth restriction is controlled by means of the axial position of the main valve member relative the valve housing.
15. A shock absorbing device for a vehicle suspension comprising: at least one working chamber, and a valve arrangement according to claim 1, for controlling the flow of a damping medium fluid to/from said at least one working chamber to control the damping characteristics of said shock absorbing device.
16. A valve arrangement for a shock absorber, said valve arrangement comprising: a valve housing comprising a first and a second port; a pilot chamber being in fluid communication with said first and/or second port, wherein a pilot pressure is defined by a hydraulic pressure in said pilot chamber; a main valve member being axially movably arranged in said valve housing and being arranged to interact with a main valve seat member in order to restrict a main fluid flow between said first and second ports in response to said pilot pressure acting on said main valve member; wherein the main valve seat member is movable between a first compression stroke position and a second rebound stroke position so that, during the compression stroke, the main fluid flow is restricted at a first restriction and a cooperating serially arranged second restriction, and, during the rebound stroke, the main fluid flow is restricted at a third restriction and a cooperating serially arranged fourth restriction, wherein said main valve member further comprises a geometrically defined circumferential aperture having a radial inner wall and a radial outer wall, wherein the radial inner wall forms a part of the fourth restriction and the radial outer wall forms a part of the third restriction.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further details and aspect of the present invention will become apparent from the following detailed description with reference to accompanying drawings, in which:
(2) FIG. 1a shows an exploded view of an embodiment of the valve arrangement,
(3) FIG. 1b shows an exploded view of an embodiment of the valve arrangement,
(4) FIG. 2a shows a cross-section of an embodiment when the main valve member is in a closed position to block a main flow from the first port to the second port,
(5) FIG. 2b shows a cross-section of an embodiment when the main valve member is in a closed position to block a main flow from the first port to the second port,
(6) FIG. 3a shows a close-up cross-section of FIG. 2a, where the main valve member is in a closed position to block a main flow from the first port to the second port,
(7) FIG. 3b shows a close-up cross-section of FIG. 2b, where the main valve member is in a closed position to block a main flow from the first port to the second port,
(8) FIG. 4a is a close-up of the device in FIG. 3a, but where the main valve member and main valve seat member is in a partly open position to allow a regulated main flow from the first port to the second port, i.e. a flow during compression stroke,
(9) FIG. 4b is a close-up of the device in FIG. 3b, but where the main valve member and main valve seat member is in a partly open position to allow a regulated main flow from the first port to the second port, i.e. a flow during compression stroke,
(10) FIG. 5a is a close-up of the device in FIG. 3a, but where the main valve member is in a partly open position to allow a regulated main flow from the second port to the first port, i.e. a flow during rebound stroke,
(11) FIGS. 5b and 5c are two close-ups of the device in FIG. 3b, but where the main valve member is in a partly open position to allow a regulated main flow from the second port to the first port, i.e. a flow during rebound stroke,
(12) FIG. 6a shows a cross-section of a side portion of the main valve seat member in one embodiment, where the lifting surface area during the closed position of the main valve member is illustrated,
(13) FIG. 6b shows a cross-section of a side portion of the main valve seat member where the lifting surface area during regulated compression stroke is illustrated,
(14) FIG. 6c shows an illustration of the main valve seat member and the first, second and fifth orifices at a given stroke length S,
(15) FIG. 6d shows a graph over the orifice openings vs. the stroke length,
(16) FIG. 6e shows a graph over the flow (q) vs. Pressure (P) in three damping characteristics scenarios,
(17) FIG. 7a shows two illustrations of the main valve seat member when having an integrated blocking means,
(18) FIG. 7b shows an illustration of the main valve seat member and the blocking means when the blocking means is a separate unit,
(19) FIG. 7c shows an illustration of the third, fourth and sixth orifices at a given stroke length S,
(20) FIG. 7d shows a top view of the main valve seat member in one embodiment, and
(21) FIG. 8 shows a side cross-sectional illustration of a shock absorber having a valve arrangement placed therein.
DETAILED DESCRIPTION OF EMBODIMENTS
(22) The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout the application. However, the main valve seat member 9 is denoted with either valve seat member 9, 9a, 9b or 9c. The alternative versions (9a, 9b, 9c) may be substituted for each other in the different embodiments described below. Therefore, any reference made to either one of 9, 9a, 9b or 9c should be interpreted as a disclosure for all alternative embodiments of the valve seat member. Sometimes only 9 is used as a reference in order to facilitate the reading of the text.
(23) The inventive concept will be described with two major embodiments, the first one shown in FIGS. 1a, 2a, 3a, 4a, 5a, and 7a where the moveable valve member 9 has an integrated blocking means comprising blocking portions 91 and intermediate openings 92 for regulating the orifice of the third restriction R3. In the other major embodiment, shown in e.g. FIGS. 1b, 2b, 3b, 4b, 5b, and 7b the blocking means 10 is a separate unit which comprise blocking portions 91 and intermediate openings 92, having the same function as the blocking portions and intermediate openings in the first embodiment. The two embodiments still have the same function and are merely two ways of solving the same problem. Further, anything described in relation to the first embodiment may be equally applicable to the second embodiment and vice versa.
(24) FIG. 1a shows a cross-sectional exploded view of a valve arrangement. The valve arrangement 1 comprises a valve housing 2. The valve housing has an upper portion at the top of the figure and a lower portion at the bottom of the figure, which are separated in the figure, but when in use they are mechanically coupled, e.g. by press fit or a threaded engagement. The arrangement further comprises a main valve member 4 and a control valve member 5, inside the control valve member 5 there is a pilot valve member 6 (shown in e.g. FIG. 2a) acting as a pressure regulator. The valve members are biased inside the housing by biasing means 14, 19 (shown as springs). The biasing means may be any type of spring providing a suitable spring force and fitting into the housing space.
(25) The figure further illustrates the second port 8 in the lower portion of the valve housing 2. Moreover, the arrangement comprises the movable main valve seat member 9, which is further illustrated in the following figures, especially FIG. 7b. The valve seat member 9a comprise an integrated blocking means comprising blocking portions 91 and intermediate openings 92, as has been explained above. Further, an alternative main valve seat member 9b is illustrated. The alternative main valve seat member 9b also comprise an integrated blocking means comprising blocking portions 91 and intermediate openings 92. The difference is that the blocking portions 91 decrease in size as the distance from the base of the valve seat member increase. Correspondingly, the intermediate openings 92 in the alternative valve seat member 9b increase in size as the distance from the base of the valve seat member increase. Hereby, the blocking means may block the most damping fluid in the lower parts of the stroke, and allow an increased flow as the strokes increase. Thus, the orifice O.sub.R3 of R3 will increase more than linearly relative the stroke length, as is illustrated in FIG. 6d. Most details in FIG. 1a will be further explained in relation to FIGS. 3a-5a, where their respective function also will be described. FIG. 1a is mainly included in the application to clarify the form of each component and thereby facilitate the reading and understanding of the application.
(26) FIG. 1b is a corresponding illustration of the valve arrangement as is shown in FIG. 1a, but wherein the blocking means 10 is a separate unit which comprise blocking portions 91 and intermediate openings 92. As has been explained above, these have the same function as the blocking portions 91 and intermediate openings 91 in the first embodiment. Further, FIG. 1b comprise a biasing means 11 for holding the blocking unit 10 in position. In FIG. 1b the biasing unit 11 is illustrated as a wave washer, but may be any type of biasing means such as a spring or an elastic material, as long as it provides enough biasing force and can be fitted into the housing. Although it is not illustrated in FIG. 1b, it would be fully possible to adjust the form of the blocking means 10 so that the blocking portions 91 increase in size as they the distance from the base of the blocking means increase. Correspondingly, the intermediate openings 92 decrease in size as the distance from the base of the blocking means increase. Hereby, the blocking means may block the most damping fluid in the lower parts of the stroke, and allow an increased flow as the stroke increase. Thus, the orifice O.sub.R3 of R3 will increase more than linearly relative the stroke length.
(27) FIGS. 2a and 3a shows a cross-section of an embodiment of the valve arrangement 1 when the main valve member 4 is in a closed position to block a main flow (not shown) from the first port 7 to the second port 8, wherein FIG. 3a is a close-up cross-section of FIG. 2a. The valve arrangement 1 comprises a valve housing 2, a pilot chamber 3, a main valve member 4, and a control valve member 5. The valve housing 2 comprises a first and a second port 7, 8. In the illustrated embodiment, the first and second ports act as inlet and outlet ports, respectively, for inlet and outlet of hydraulic fluid. The pilot chamber 3 is defined by the space formed between the upper surface 41 of the main valve member and inner walls of the valve housing 2. The pilot chamber 3 is in fluid communication with the first port 7 via a first axial through hole 32 in the main valve member 4 and with the second port 8 via a second axial through hole 33 in the main valve member 4. There may be several axial holes provided in the main valve member for these purposes. The pilot pressure Pp acting on the upper surface 41 of the main valve member 4 is defined by a hydraulic pressure in the pilot chamber 3.
(28) The main valve member 4 is axially movably arranged in the valve housing 2 and is arranged to interact with the movable main valve seat member 9a in order to restrict or regulate a pressure in a main fluid flow 30 (shown in e.g. FIGS. 4a and 5a) between the first port 7 and the second port 8 in response to a pilot pressure Pp acting on an upper surface 41 of the main valve member 4. In this embodiment, the main valve member 4 is held towards the main valve seat member 9a in a closed position. The main valve member may be resiliently loaded by any spring members or may itself be flexible and/or resilient to achieve a desired resilient loading towards the movable main seat valve member 9a.
(29) The control valve member 5 is of a substantially cylindrical shape and is arranged coaxially with and partially within the main valve member. The control valve member 5 is furthermore movable in an axial direction relative the main valve member in response to an actuating force acting on the control valve member. In this embodiment, the actuating force is received by an actuating rod 35. The actuating rod may be an axially movable member on which a solenoid exerts a force in response to an electric current.
(30) Further, the closed state shown in FIG. 2a may be derived from that the pressure from port 7 and/or 8 has not yet reached a threshold value when the main valve member 4 is lifted towards the pilot chamber 3. This threshold value corresponds to when the lifting force generated from the pressure in any one of the first or second port 7, 8 acts on a lifting areas 42, 43 of the main valve member 4 exceed the counter acting force from the pilot pressure Pp in the pilot chamber 3 acting on the upper surface 41 of the main valve member 4. This is further explained in relation to FIGS. 4a and 5a where a regulated main flow 30 is illustrated.
(31) As most clearly illustrated in the close-up shown in FIG. 3a, the valve housing member comprises a circumferential aperture 25, having a radial inner wall 26 and a radial outer wall 27. In connection with the radial inner wall 26 there is another aperture forming a fifth restriction R1. The fifth restriction R1 allows the damping fluid to enter the circumferential aperture 25 so as to pressurize the movable main valve member 9 in response to a pressure in port 7. The blocking portion 91 is also illustrated as a solid wall in the cross-section of FIG. 3a. Further, FIG. 3a illustrates a bleed flow 20 flowing between the first and second ports through an opening in the main valve member 4, into the control valve member 5 and passing along the pilot valve member 6 and then back through the control valve member 5 and the main valve member 4. This bleed flow is a limited flow which is substantially lower flow than the maximum main fluid flow. The regulated bleed flow 20 corresponds to the first stage flow q1 in FIG. 6e, i.e. before the three curves depart from each other. This will be further elaborated in relation to FIG. 6e.
(32) FIGS. 2b and 3b are corresponding to FIGS. 2a and 3a, respectively, but with the difference that the blocking means 10 is a separate unit which comprise blocking portions 91 and intermediate openings 92, as has been explained above. Also, the biasing means 11 is illustrated in FIGS. 2b and 3b. The biasing member 11 is holding the blocking means 10 against the movable valve member 9b with support from a surface on the main valve member 4.
(33) FIGS. 4a and 4b are two close-up illustrations of the two embodiments, wherein the main valve member 4 and main valve seat member 9a is in a partly open position to allow a regulated main flow 30 from the first port 7 to the second port 8, i.e. a flow during compression stroke. As illustrated, the movable main valve seat member 9 and main valve member 4 are held together in a position axially displaced relative the valve housing 2 when compared to the closed position in FIGS. 2a/2b and 3a/3b. In this position, a regulated main fluid flow 30 is allowed from the first port 7 to the second port 8, and is restricted by the first restriction R1 plus the fifth restriction R1 first (upstream, closest to the first port) and then restricted by the second restriction R2 downstream of the first restriction R1. The radial inner wall 26 in cooperation with the movable valve seat 9 forms a part of the first restriction (R1) and the radial outer wall (27) together with the movable valve seat 9 form a part of the second restriction (R2). In any partly open state the orifice of the first restriction R1 is smaller than the orifice of the second restriction R2, since the two restrictions are formed as circumferential restrictions and being radially displaced. Since the second restriction has a larger circumference its orifice will always be larger than the orifice of the first restriction, when formed with a common delimiter upwards (the movable valve seat member 9) and downwards (the radial side walls of the housing). Further, the fifth restriction R1 has a constant opening. Hereby, the sum of the first R1 and fifth R1 restriction is initially larger than the second restriction R2, but as the stroke S increases the second restriction becomes larger than the sum of the first and fifth restriction, this is illustrated in FIGS. 6c and 6d.
(34) Thus, in FIGS. 4a and 4b a pressure from the damping fluid in port 7 causes the opening axial displacement of the main valve member 4 (acting on the lifting areas 42 and 43) and the main valve seat member 9 (acting on the lifting area 21a as illustrated in FIG. 6b). The movement is, as earlier explained, dependent on the counteracting pressure from the pilot chamber 3 acting on the main valve member 4. Hereby, a regulated main flow of damping fluid is allowed to flow from the first to the second port 7, 8. This type of regulation corresponds to the second stage flow q2 in FIG. 6e, i.e. after the three curves depart from each other. Since two serial and cooperative restrictions R1 and R2 are used to regulate the flow, a soft opening when going from the first stage q1 to the second stage q2 may be achieved. This will be further elaborated in relation to FIG. 6e as mentioned before.
(35) FIGS. 5a and 5b are also a close-up of the view in FIG. 2a/2b, but where the main valve member 4 is in a partly open position to allow a regulated main flow 30 from the second port 8 to the first port 7, i.e. a flow during rebound stroke.
(36) When comparing FIG. 5a to FIG. 4a, it is only the movable main valve seat member 9 that has been moved from being arranged tightly against the main valve member 4, to instead being arranged tightly against the valve housing 2. This is achieved through a flow (pressure) of damping fluid from the second port 8 to the first port 7, which acts on the upper surface, being a lifting area 22, of the movable main valve seat member 9 and also acts on the lifting area 43 of the main valve member 4, but in an opposite direction so that the main valve member 4 and the main valve seat member are separated. The pressure in the second port 8 will keep the main valve seat member 9 pressed against the valve housing 2 throughout the rebound stroke. Also, depending on the level of pressure, the opening between the main valve member 4 and the main valve seat member determines both the orifices O.sub.R3, O.sub.R4 of third restriction R3 and the fourth restriction R4. The third restriction R3 enables the pressure-regulated flow in rebound stroke. Since the two serial and cooperative restrictions R3 and R4 are used to regulate the flow, a soft opening when going from the first stage q1 to the second stage q2 may be achieved. The third restriction R3 is partly shielded along its outer envelope surface by the blocking portions 91. Hereby, the orifice of R3 is smaller than the orifice of R4 regardless of the stroke length.
(37) As further shown in FIG. 5a, the main valve member 4 comprise a flange portion for cooperating with the movable valve member to constitute the third and fourth restrictions R3, R4. The flange part meshes with the blocking portions 91. Further, the main valve member comprises a geometrically defined circumferential aperture 45. The aperture has a radial inner wall 46 and a radial outer wall 47. The radial inner wall 46 forms a part of the fourth restriction R4 and the radial outer wall 47 forms a part of the third restriction R3, in cooperation with the movable valve member 9. Further, the aperture 46, inner and outer walls 46, 47 may all be arranged in the flange portion. Further, the sixth restriction R3, is an opening into the aperture 45, which fluidly connects the second port 8 to the aperture 47. Thus, the aperture 46, inner wall 46 and outer wall 47, in the main valve member 4 has a similar function as the aperture 26, inner wall 26 and outer wall 27 in the housing as explained above, but for achieving a soft opening in the rebound flow, in the same way as soft opening is achieved in the compression flow.
(38) When comparing FIG. 4a and FIG. 5a, the above-mentioned advantage with having a movable valve seat member 9 and thereby getting a more flexible area pressure ratio between compression pressure area and rebound pressure area may be understood. In the illustrated embodiment the area ratio between the compression area and the rebound area may be adjusted without changing the pilot pressure area. In a solution where the main valve seat is fixed, the sum of the compression pressured area and rebound pressured area is equal to the pilot pressured area. However, with a movable main valve member, it is possible that the sum is greater than the pilot pressured area, since the movable valve seat member is moved and thereby the compression pressure and rebound pressure acts at different surfaces. This allows forming the valve arrangement to generate the desired damping forces in both the compression stroke and the rebound stroke without compromising with one of the forces.
(39) Further, FIGS. 5b and 5c shows two different view of the same embodiment and state of the valve arrangement. FIG. 5b mainly illustrates the main flow 30 (which is left out of FIG. 5c for clarity reasons). In both FIGS. 5b and 5c the blocking means is a separate unit, not being integrated with the movable valve seat member 9. On the left side the flow through the third R3 and fourth R4 restrictions is illustrated. One the right hand side the cross-section is taken through the blocking portion 91 why the flow takes a path on a side of said blocking portion 91, and though the sixth restriction R3, always being open (illustrated by the top dotted path in the right part of the figure.
(40) Moreover, 5c illustrates the details also shown in FIG. 5a, but in the embodiment with the blocking means being a separate blocking unit 10. Just below the inner wall 46 of the main valve member 4, one opening 92 in the blocking unit 10 is illustrated. This correspond to the area O.sub.R3 in FIG. 7c, where the main fluid flow may flow when the valve is at least partly opened, i.e. the valve is more than zero.
(41) FIGS. 6a and 6b further illustrates a principle sketch of the pressurized areas of the movable valve seat member 9. In FIG. 6a the pressurized areas 21b, 21c and 22 corresponds to the area acting on the movable valve seat member 9 when the main valve is closed, as illustrated in e.g. FIGS. 2a and 3a. The area 21b corresponds to the portion of the movable valve seat member protruding from the valve housing in a radially inwards direction. The area 21c corresponds to the portion of the movable valve seat member arranged on top of the circumferential aperture 25 in the valve housing. That is, this aperture may be filled with pressurized damping fluid. Further, the area 22 corresponds to the portion of the movable valve seat member 9 extending in a radially outwards direction from the main valve member's radially outer corner.
(42) Further, FIG. 6b shows a cross-section of a side portion of the main valve seat member where the lifting surface area during regulated compression stroke is illustrated. The pressurized area 21a on the movable valve seat member 9 illustrated is when the main valve member is at least partly opened. The area corresponds to the whole lower surface of the movable valve seat member 9.
(43) FIG. 6d shows a graph over the orifice openings O.sub.R1+O.sub.R1 and O.sub.R2 as a function of the stroke length S. The first orifice O.sub.R1 corresponds to the orifice of the first restriction R1. This orifice O.sub.R1 is also illustrated by the envelope surface of the circle in FIG. 6c, and denoted with O.sub.R1, which is thus dependent on the stroke length S. The stroke length is the axial distance between the movable valve seat member 9 and the main valve housing 2, when being in a regulated position, see for example in FIG. 3b. The second orifice O.sub.R2 corresponds to the orifice O.sub.R2 of the second restriction R2. This orifice is also illustrated by the envelope surface of the circle in FIG. 6c, and denoted with O.sub.R2. The fifth orifice O.sub.R1 corresponds to the orifice of the fifth restriction R1. This orifice O.sub.R1 is also illustrated by a surface in FIG. 6c denoted with O.sub.R1, which corresponds to the opening into the circumferential aperture in the main valve housing 2. As already explained above, FIG. 6c shows an illustration of a cross-sectional side-view of the main valve seat member where the first O.sub.R1, second O.sub.R2 and fifth O.sub.R1 orifices are illustrated at a given stroke length S. From this illustration it is apparent how the first O.sub.R1 and second O.sub.R2 orifices vary with the stroke length S, but the fifth O.sub.R1 orifice is static.
(44) In the initial phase of the regulated compression stroke, i.e. when R1 and R2 is just opening from a closed position, the restriction will be carried out in the second restriction, which is shown in FIG. 6d, since the orifice of the second restriction R2 is smaller than the orifice of the first and fifth restriction R1+R1, in said initial phase. As soon as the orifice of the second restriction O.sub.R2 is larger than the combined orifice of the first and fifth restriction O.sub.R1+O.sub.R1, the restriction is instead carried out at the first and fifth restrictions.
(45) Further, as the graph in FIG. 6d illustrates, the combined first and fifth orifices O.sub.R1 and O.sub.R1 are larger than the second orifice O.sub.R2 during the initial stroke, but at one point, the second orifice O.sub.R2 is larger than the combined first and fifth orifices O.sub.R1 and O.sub.R1, and increases faster during the same stroke length.
(46) The size relationships between the orifices of the different restrictions may vary without departing from the inventive concept. By adjusting the orifice size relationships, the intersecting point between O.sub.R1+O.sub.R1-curve and the O.sub.R2-curve the shown in FIG. 6d may be moved. The orifice size of O.sub.R1 is represented by where the O.sub.R1+O.sub.R1-curve intercepts the Y-axis. The relation between the size of the first and second restrictions' orifices O.sub.R1 is illustrated by the different inclinations of the two curves in FIG. 6d. Further, by increasing the relative size of the fifth orifice O.sub.R1 relative the maximum orifice size of the first orifice O.sub.R1 the soft opening is prolonged.
(47) There is no illustration of the orifices of R3, R3 and R4, but they correspond to the same principles as disclosed in FIG. 6d. Wherein O.sub.R3 correspond to O.sub.R1, O.sub.R3 correspond to O.sub.R1 and O.sub.R4 correspond to O.sub.R2.
(48) There is further a dotted bended line in FIG. 6d, which represents the orifice O.sub.R3+O.sub.R3 when the alternative blocking means 9b is used, i.e. wherein the blocking means 9b blocks the most damping fluid in the lower parts of the stroke, and allow an increased flow as the strokes increase. The form of the blocking portion 91 will determine the curving of the O.sub.R3+O.sub.R3 dashed line, and may be adapted to a desired character.
(49) The maximum orifice size of the first orifice O.sub.R1 may be about 50%-95% of the maximum orifice size of the second orifice O.sub.R2. In one embodiment the maximum orifice size of the first orifice O.sub.R1 is about 70%-90% of the maximum orifice size of the second orifice O.sub.R2. In another embodiment maximum orifice size of the first orifice O.sub.R1 is about 75%-85% of the maximum orifice size of the second orifice O.sub.R2.
(50) The orifice size of the fifth orifice O.sub.R1 may be about 0.1%-10% of the maximum orifice size of the first orifice O.sub.R1. In one embodiment the orifice size of the fifth orifice O.sub.R1 is about 0.3%-3% of the maximum orifice size of the first orifice O.sub.R1. In another embodiment the orifice size of the fifth orifice O.sub.R1 is about 0.5%-1% of the maximum orifice size of the first orifice O.sub.R1.
(51) Analogy, the maximum orifice size of the third orifice O.sub.R3 may be about 50%-95% of the maximum orifice size of the fourth orifice O.sub.R4. In one embodiment the maximum orifice size of the third orifice O.sub.R3 is about 70%-90% of the maximum orifice size of the fourth orifice O.sub.R4. In another embodiment maximum orifice size of the third orifice O.sub.R3 is about 75%-85% of the maximum orifice size of the fourth orifice O.sub.R4.
(52) The orifice size of the sixth orifice O.sub.R3 may be about 0.1%-10% of the maximum orifice size of the third orifice O.sub.R3. In one embodiment the orifice size of the sixth orifice O.sub.R3 is about 0.3%-3% of the maximum orifice size of the third orifice O.sub.R3. In another embodiment the orifice size of the sixth orifice O.sub.R3 is about 0.5%-1% of the maximum orifice size of the third orifice O.sub.R3.
(53) Finally, FIG. 6e shows graph over the pressure P as a function of the flow q in a compression stroke, in three different dampers with different damping characteristics. All functions comprise a common first stage q1, where a regulated bleed flow is illustrated. In the second stage q2, starting from where the three functions separated from each other, corresponds to a pressure regulated main fluid flow. The first damping character DC1, illustrates a sharp opening, which is the common behaviour in 2-way valves today. The second and third functions DC2 and DC3, both illustrate a soft opening, i.e. when the solution described in this application is used. The difference between the two is the orifice size of the fifth restriction R1. That is, by altering the size of the fifth restriction's orifice the character of the soft opening may be adjusted. In the second function DC2, the fifth orifice O.sub.R1 is smaller than in the third function DC3 which consequently has a larger orifice O.sub.R1. The illustrated pressure P as a function of the flow q is also applicable in the rebound stroke. However, then the size of the sixth restriction's orifice O.sub.R3 should be adjusted in relation to the third O.sub.R3 and fourth O.sub.R4 restriction orifices in order to adjust the character of the soft opening.
(54) FIG. 7a is an illustration of the main valve seat member 9a when having an integrated blocking means. The blocking means consists of blocking portions 91. There may be a plurality of blocking portions 91, in this specific example three portions are used, and evenly distributed. In other embodiments more blocking portions may be used, e.g. 4, 5, 6, 7 or 10 or more. Between the blocking portions 91 there are openings 92 allowing the damping fluid to flow between the first and second ports. FIG. 7a also comprise the alternative main valve seat member 9b when having an integrated blocking means, but where the blocking portions 91 decrease in size as the distance from the base of the valve seat member increase. Correspondingly, the intermediate openings 92 in the alternative valve seat member 9b increase in size as the distance from the base of the valve seat member increase. Hereby, the blocking means may block the most damping fluid in the lower parts of the stroke, and allow an increased flow as the strokes increase. This has also been described in relation to FIG. 6d.
(55) FIG. 7b shows a perspective view (from below) of an alternative embodiment wherein the main valve seat member and the blocking means are represented by separate units. The blocking unit 10 then comprise the blocking portions 91 and intermediate openings 92. There may be a plurality of blocking portions 91 (and consequently openings), in the illustrated example three blocking portions are used, and evenly distributed. In other embodiments more portions may be used, e.g. 4, 5, 6, 7 or 10 or more.
(56) FIG. 7c shows an illustration of the third, fourth and sixth orifices at a given stroke length S. The figure corresponds to FIG. 6c, but represents the orifices for the restrictions in the rebound stroke. The orifice O.sub.R3 is illustrated by the envelope surface of the lower circle, but with the without the striped areas 91 corresponding to the blocking portions 91. Thus, the third orifice O.sub.R3 is dependent on the stroke length S. The stroke length is in the rebound flow, the axial distance between the movable valve seat member 9 and the main valve member 4, when being in a regulated position, see for example in FIG. 5a/5b. The fourth orifice O.sub.R4 corresponds to the orifice of the fourth restriction R4. This orifice is illustrated by the envelope surface of the top circle, and denoted with O.sub.R4. The sixth orifice O.sub.R3 corresponds to the orifice of the sixth restriction R3. This orifice O.sub.R3 is also illustrated by a surface in FIG. 7c, which corresponds to the opening into the circumferential aperture into the aperture 45. From FIG. 7c it is apparent how the third O.sub.R3 and fourth O.sub.R4 orifices cooperatively vary with the stroke length S, but the sixth orifice O.sub.R3 is static and stroke independent.
(57) FIG. 7d illustrates the movable valve seat member 9c when being a shim or washer, from a top view. It is shown that the movable valve seat member 9c has an outer diameter D1 and an inner diameter D2. Furthermore, the washer comprises three radial steering projections 93. The steering projections are sized and adapted to mesh with the main valve housing 2. Furthermore, the space between the at least three radial steering projections 93 in the washer forms intermediate ports 94 for allowing the main fluid flow 30 passing from the first 7 to the second port 8 during the compression stroke. The steering projections 93 and intermediate ports 94 in the embodiment are arranged so that not a single steering projection 93 has an opposing steering projection on the other side of the washer. With other words, a straight line through any of the projection 93 and the center of the washer will not go through a second steering 93 projection but instead go through an intermediate port 94. The reason to this design is that jamming of the movable valve seat member 9 may be prevented if it is tilted (i.e. rotated around an axis being perpendicular to its center axis) since there are no two directly opposite projections along the diameter of the washer. It would also be possible to have more radial steering projections, as long as they are distributed along the circumferential of the movable valve seat member 9 so as to avoid jamming if it is tilted. Although the steering projections are only illustrated in relation to the washer-shaped valve seat member 9c, the projections could be applied to the other embodiments of the valve seat member 9a, 9b.
(58) Finally, FIG. 8 shows a side cross-sectional illustration of a shock absorber 100 having a valve arrangement placed therein. Not all the details of the shock absorber are shown since it belongs to known art. Instead FIG. 8 is merely an illustration to show in what way the valve arrangement described herein may be implemented in a shock absorber. The shock absorber comprises a first working chamber 101 and a second working chamber 102. Further, the shock absorber 100 comprises a piston rod 103 attached to the housing of the valve arrangement 1. A sealing member 104 is arranged to the valve housing and divides the first working chamber 101 from the second working chamber 102. The first working chamber 101 is fluidly connected to the first port 7 of the valve arrangement and the second working chamber 102 is fluidly connected to the second port 8 of the valve arrangement 1. It should be further understood that the shock absorber in FIG. 1 also illustrates how a valve arrangement 1 would be mounted in e.g. a front fork or equivalent damping equipment for a vehicle.
(59) Although exemplary embodiments of the present invention have been shown and described, it will be apparent to the person skilled in the art that a number of changes and modifications, or alterations of the invention as described herein may be made. Moreover, the different embodiments described above may be combined in different ways without departing from the scope of the inventive concept. Thus, it is to be understood that the above description of the invention and the accompanying drawing is to be regarded as a non-limiting example thereof and that the scope of the invention is defined in the appended patent claims.
