Valve arrangement and method for controlling pilot pressure in a valve arrangement
阅读说明:本技术 阀布置和用于控制阀布置中的先导压力的方法 (Valve arrangement and method for controlling pilot pressure in a valve arrangement ) 是由 哈坎·马姆博格 弗雷德里克·拉尔森 比约恩·斯特哈尔内 于 2019-02-11 设计创作,主要内容包括:一种阀布置(1)和一种用于控制减震器的阀布置(1)中的先导压力的方法,其中该阀布置包括可相对于主阀构件在轴向方向上移动的控制阀构件(5)、与第一端口(7)和/或第二端口(8)流体连通的先导室(3)。该布置和方法包括在主动控制模式期间对该控制阀构件(5)进行压力释放(AM S1)并且施加用于控制该先导压力(Pp)的致动力(AM S2)。进一步地,在故障安全控制模式期间,通过该先导压力(P<Sup>P</Sup>)控制(FM S1)该控制阀构件(5)。最后,在该主动控制模式和该故障安全控制模式二者期间,通过至少一个公共阀座(R<Sub>2</Sub>)限制(S3)该先导流体流(PF<Sub>C</Sub>,PF<Sub>R</Sub>)。(A valve arrangement (1) and a method for controlling pilot pressure in a valve arrangement (1) of a shock absorber, wherein the valve arrangement comprises a control valve member (5) movable in an axial direction with respect to a main valve member, a pilot chamber (3) in fluid communication with a first port (7) and/or a second port (8). The arrangement and method include pressure releasing (AM S1) the control valve member (5) and applying an actuation force (AM S2) for controlling the pilot pressure (Pp) during an active control mode. Further, during the fail-safe control mode, the pilot pressure (P) is passed P ) The control valve member (5) is controlled (FM S1). Finally, during both the active control mode and the fail-safe control mode, by at least one common valve seat (R) 2 ) Restricting (S3) the pilot fluid flow (PF) C ,PF R )。)
1. A valve arrangement (1) for a shock absorber, the valve arrangement comprising:
a valve housing (2) comprising a first and a second port (7, 8),
-a pilot chamber (3) in fluid communication with the first and/or second port, wherein a hydraulic pressure in the pilot chamber defines a pilot pressure (P)P);
-a main valve member (4) axially movably arranged in the valve housing and arranged to interact with a main valve seat (9) of the valve housing to restrict a main fluid flow (21) between the first and second ports (7, 8) in response to the pilot pressure acting on the main valve member;
-a control valve member (5) movable in an axial direction relative to said main valve member (4) and resiliently loaded in a direction towards said pilot chamber (3),
characterised in that the valve arrangement is configured such that
-during an active control mode, controlling a pilot fluid flow (PF) in response to an actuation force acting on the control valve member (5)C,PFR),
-controlling the pilot fluid flow (PF) in response to a pilot pressure acting on the control valve member (5) during a fail-safe control modeC,PFR) And in that,
-the pilot fluid flow (PF) during both the active control mode and the fail-safe control modeC,PFR) Is restricted by at least one common restriction section (R2).
2. Valve arrangement according to claim 1, wherein the control valve member (5) is pressure relieved during said active control mode.
3. A valve arrangement according to claim 1 or 2, wherein the control valve member (5) is pressure controlled during said fail-safe control mode.
4. A valve arrangement according to any one of claims 1-3, wherein during the fail-safe control mode the pilot pressure acting on the control valve member (5) is limited by a first limitation (R)1) And a spring force adjustment from a biasing member (12) elastically loading the first movable restriction member (31) in a direction towards the pilot chamber (3).
5. A valve arrangement according to claim 4, wherein the valve arrangement further comprises a geometrically defined axial stop (13) for preventing the first movable limiting member (31) from moving axially beyond the stop in the biasing direction.
6. Valve arrangement according to claim 5, wherein the pilot pressure is regulated at a pilot pressure limiting portion (R1) formed between the axial stop portion (13) and the first movable limiting member (31).
7. Valve arrangement according to any of claims 1-6, wherein the actuator (35) has an actuation force range capability such that the control valve member (5) has a corresponding stroke length.
8. Valve arrangement according to claim 7, wherein the pilot pressure acting on the control valve member (5) during the fail-safe control mode corresponds to the force in the middle part of the actuation force range of the actuator (35).
9. According to any one of claims 1-8The valve arrangement as described, further comprising a pilot valve member (6) axially movable within the control valve member (5), the pilot valve spool being arranged to interact with a pilot valve arrangement (30) of the control valve member for counteracting a pilot fluid flow (PF) flowing out of the pilot chamberC,PFR) A restriction is made.
10. The valve arrangement according to claim 9, wherein the pilot valve arrangement (30) comprises said first movable restriction member (31), a second movable restriction member (32) and a biasing member (12) arranged between said first restriction member (31) and said second restriction member (32).
11. The valve arrangement according to claim 10, wherein the pilot valve arrangement (30) further comprises a sleeve member (33) in which the biasing member (12) is arranged, and wherein the sleeve member (33) is axially arranged between the first and second restriction members (31, 32).
12. Valve arrangement according to claim 11, wherein the sleeve member (33) comprises at least two separate parts which fit together to enclose a restriction, thereby realizing the common prior flow restriction (R2) and pilot pressure restriction (R1).
13. Valve arrangement (1) according to claim 5, wherein the free length of the biasing member (12; 14) is adapted to bring the control valve member (5) into abutment against said axial stop (13) when said actuation force acting on the control valve member is smaller than a predetermined value.
14. A damping device (100) for a vehicle suspension, comprising:
-at least one working chamber (101, 102), and
-a valve arrangement according to any of claims 1-13 for controlling the flow of damping medium fluid to/from said at least one working chamber for controlling the damping characteristics of the shock absorbing device.
15. A method for controlling a pilot pressure in a valve arrangement (1) of a shock absorber, wherein the valve arrangement comprises a control valve member (5) movable in an axial direction with respect to a main valve member, a pilot chamber (3) in fluid communication with a first port (7) and/or a second port (8), wherein a pilot pressure (Pp) is defined by a hydraulic pressure in said pilot chamber, the method comprising the steps of:
-during active control mode
o pressure relief (AM S1) of the control valve member (5), and
o applying an actuation force (AM S2) for controlling the pilot pressure (Pp),
-during a fail-safe control mode
o passing the pilot pressure (P)P) Controlling (FM S1) the control valve member (5), and
-during both the active control mode and the fail-safe control mode
o through at least one common valve seat (R)2) Restricting (S3) the pilot fluid flow (PF)C,PFR)。
Technical Field
The present invention generally relates to the field of valve arrangements. In particular, the present invention relates to a valve arrangement for controlling the flow of damping medium in a shock absorber.
Background
Generally, within the technical field of shock absorbers comprising a pilot valve, a pressure regulator (i.e. a valve arrangement) is used to control the flow of damping medium between a compression chamber and a rebound chamber during the reciprocating movement of a piston in a damping medium filling chamber of the shock absorber. The piston is connected to the wheel or chassis via a piston rod, while the chamber is connected to the one of the wheel or chassis to which the piston is not connected. During a compression stroke, the piston moves axially in a direction towards the compression chamber, thereby pressurizing the damping medium in the compression chamber. During a rebound stroke, the piston moves axially towards the rebound chamber, i.e. in the opposite direction, thereby pressurizing the damping medium in the rebound chamber. Depending on the function of the shock absorber, the pressurized damping medium needs to be transferred from the pressurized chamber to the other chamber, i.e. from the compression chamber to the rebound chamber, or vice versa. It is necessary to control the flow of damping medium to obtain a damping effect of the piston and thus of the shock absorber, i.e. damping the relative movement between the wheel and the chassis.
The pressure control of the damping medium flow in the shock absorber depends on the pressure generated by the valve arrangement. Pressure regulators in shock absorbers are generally provided with an axially movable or deflectable valve member, such as a washer, cone, or shim, acting on a seat part. Pressure control is achieved by equalization or balancing of forces, for example, between a pressure and/or flow force acting on the valve member in one direction and a reaction or counter force (such as one or more of a spring force, a friction force, or a pilot pressure force) acting on the valve member in an opposite direction. When the piston of the shock absorber moves at a speed such that the pressure and/or flow force becomes greater than the opposing or reactive force, the movable valve member is forced away from the seat member, thereby opening the flow passage. Thus, the movable valve member is forced to open in a stroke defined by the flow generated as a function of the pressure acting on the regulation area of the pressure regulator.
Conventional valve arrangements of the pressure regulating type described above typically have the disadvantage that when the solenoid or control system experiences an electrical or mechanical failure, the valve may be in an open or closed state; if the valve is in an open state, a flow path between the compression and rebound chambers is opened, resulting in substantially unrestricted flow of hydraulic fluid between the chambers and therefore substantially no damping force. Alternatively, when a fault causes the valve to be in a closed state, the flow path is substantially closed, resulting in an excessively high damping force.
Prior art valve arrangements for shock absorbers have a fail-safe control mode in which a bypass flow allows a predetermined flow of damping medium between the chambers. However, these bypass flows typically provide damping forces that are less suitable for the desired damping characteristics than active damping.
Accordingly, there is a need for a valve arrangement for a shock absorber having improved damping characteristics during a fail-safe control mode for a selected application.
Disclosure of Invention
It is an object of the present invention to provide an improved valve arrangement having a fail-safe control mode with improved damping characteristics.
The present invention is based on the insight of the inventors that by forming a valve arrangement wherein the pilot fluid flow is restricted by at least one common restriction during the active control mode and the fail-safe control mode, improved damping characteristics can be provided in the fail-safe control mode, since the damping in the fail-safe control mode will follow the adjustments made to the active control mode.
In one embodiment, the object is achieved by a valve arrangement for a shock absorber, comprising a valve housing comprising a first port and a second port, and a pilot chamber in fluid communication with the first port and/or the second port. Wherein a pilot pressure is defined by a hydraulic pressure in the pilot chamber, a main valve member being axially movably arranged in the valve housing and arranged to interact with a main valve seat of the valve housing to restrict a main fluid flow between the first and second ports in response to the pilot pressure acting on the main valve member. The arrangement further comprises a control valve member movable in axial direction relative to said main valve member and resiliently loaded in a direction towards said pilot chamber. Further, during the active control mode, pilot fluid flow is controlled in response to an actuation force acting on the control valve member. Finally, during the failsafe control mode, the pilot fluid flow is controlled in response to a pilot pressure acting on the control valve member, and during the active control mode and the failsafe control mode, the pilot fluid flow is restricted by at least one common restriction.
Thus, since the pilot fluid flow is restricted by the same valve seat during the active control mode and the fail-safe control mode, the valve characteristics in the fail-safe control mode will follow the characteristics in the active control mode. That is, for a selected actuation force, the pressure versus flow curve during the fail-safe control mode will follow the pressure versus flow curve during the active control mode. The actuator may be, for example, a solenoid actuator or any other type of force generator.
In one embodiment, the control valve member is pressure relieved during said active control mode. Thus, the pilot regulator is controlled only by the solenoid force.
In one embodiment, the control valve member is pressure controlled during said fail-safe control mode.
In one embodiment, during the failsafe control mode, a pilot pressure acting on the control valve member is regulated by a pilot pressure limitation and a spring force from a biasing member resiliently loading the first movable limiting member in a direction towards the pilot chamber.
In one embodiment, the valve arrangement further comprises a geometrically defined axial stop for preventing said first movable restriction member from moving axially beyond said stop in the biasing direction.
In one embodiment, the pilot pressure is regulated at a pilot pressure limiting portion formed between the axial stopper portion and the first movable limiting member.
In one embodiment, the actuator has an actuation force range capability such that the control valve member has a corresponding stroke length. In one embodiment the feed current of the actuator has a range between 0-3A. In one embodiment, such a feed current will produce a stroke length for the actuator of about 2-3mm, and/or a force range capability of about 0-30N.
In a further embodiment, the pilot pressure acting on said control valve member during the fail-safe control mode corresponds to a force in a middle portion of the actuation force range of the actuator. In one embodiment, the middle portion of the actuator force range of the actuator is when the feed current is between about 20% and 80% of full current capability, e.g., between about 0.6A and 2.4A full force for 3A. In yet another embodiment, the middle portion of the actuation force range of the actuator is when the feed current is between about 30% and 70% of the full current capability.
In one embodiment, the valve arrangement further comprises a pilot valve member axially movable within said control valve member, said pilot valve member being arranged to interact with the pilot valve arrangement of said control valve member for counteracting a pilot fluid flow (PF) flowing out of said pilot chamberC,PFR) A restriction is made.
In one embodiment, the pilot valve arrangement comprises said first movable restricting member, a second movable restricting member and said biasing member arranged between said first restricting member and said second restricting member.
In one embodiment, the pilot valve arrangement further comprises a sleeve member in which the biasing member is arranged, and wherein said sleeve member is axially arranged between said first restraining member and said second restraining member.
In one embodiment, the sleeve member comprises at least two separate portions that fit together to enclose the restriction means, thereby realizing the common pre-existing flow restriction and the pilot pressure restriction. In one embodiment, the sleeve member comprises three separate portions.
In one embodiment, the free length of the biasing member is adapted to urge the control valve member against said axial stop when said actuation force acting on said control valve member is less than a predetermined value.
According to a second aspect of the present invention, these objects are achieved by a damping device for a vehicle suspension, comprising: at least one working chamber and a valve arrangement according to any of the above embodiments for controlling the flow of damping medium fluid to/from the at least one working chamber to control the damping characteristics of the shock absorbing device.
According to a third aspect of the invention, these objects are achieved by a method for controlling a pilot pressure in a valve arrangement of a shock absorber, wherein the valve arrangement comprises a control valve member movable in an axial direction with respect to a main valve member, a pilot chamber in fluid communication with a first port and/or a second port, wherein the pilot pressure is defined by a hydraulic pressure in said pilot chamber. The method comprises the following steps: during an active control mode, the control valve member is pressure released and an actuation force for controlling the pilot pressure is applied. Further, the control valve member is controlled by the pilot pressure during a failsafe control mode. Finally, the pilot fluid flow is restricted by at least one common valve seat during both the active control mode and the fail-safe control mode.
Further advantages and advantageous features of the invention are disclosed in the following description. Moreover, the above-described embodiments may be combined in any manner without departing from the scope of the present disclosure. Further, the scope of protection sought is defined by the claims appended hereto.
Drawings
Further details and aspects of the invention will become apparent from the following detailed description, with reference to the accompanying drawings, in which:
figure 1 shows an exploded view of an embodiment of a valve arrangement,
figure 2 shows a cross-sectional view of an embodiment of the valve arrangement in an active control mode,
figure 3a also shows a cross-sectional view of the valve arrangement in a fail-safe control mode,
fig. 3b is a close-up of fig. 3a, to show the sleeve member in more detail,
figure 4 shows a close-up cross-sectional view of a rebounding primary fluid flow,
figure 5 shows a close-up cross-sectional view of a compressed primary fluid flow,
figure 6a shows a graph of pressure at constant fail-safe flow,
figure 6b shows a graph of the pressure range for a number of different constant currents,
figure 7 shows a cross-sectional view of a shock absorbing device including a valve arrangement therein, and
fig. 8 shows a schematic overview of the method steps according to an embodiment.
Detailed Description
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which presently 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 are intended to fully convey the scope of the invention to the technical receiver. Throughout this application, like reference numerals refer to like elements.
The first figure (i.e., fig. 1) shows a cross-sectional exploded view of the valve arrangement. This figure is provided to assist the reader in understanding the different components in subsequent figures, in which more functions and flow paths are shown. The
The arrangement further comprises a
Furthermore, the arrangement comprises a movable main
Fig. 2 shows a cross-sectional view of the valve arrangement in an active control mode. In this mode, an actuator (not shown, but above the illustration and connected to the actuator rod 35) exerts a force via the actuator rod 35 on the
Fig. 2 again shows that the valve arrangement comprises a
The
The
Further, the closed state shown in fig. 2 may result from: when the
Moving to fig. 3a and 3b, the valve arrangement is shown in the fail-safe control mode in these figures. The valve arrangement in fig. 3a and 3b is the same as already described for fig. 2. However, the actuator is in an inactive control mode (retracted position). This is illustrated by the actuator rod 35 being in the disengaged position without affecting the position of the moveable valve member.
As best seen in fig. 3b, the
The axial position of the
In the illustrated example, the free length of the
Continuing on, fig. 4 shows a close-up cross-sectional view of the lower right part of the figure, in which a resilient main
Fig. 5 shows the same close-up cross-sectional view as fig. 4, but with the compressed
Moving to fig. 6a and 6b, graphs of pilot pressure at constant flow (fig. 6a) and some constant current levels (fig. 6b) are shown. Shown in fig. 6b is the pressure and flow during the compression stroke with soft opening (a soft transition where the pressure increases exponentially with the flow to a linear increase), whereas the curve for rebound flow is in principle the same, but without the soft opening characteristic. Further, for fig. 6a, the pressure versus current graph applies to both compression flow and rebound flow.
Fig. 6a shows two extreme fail-safe control mode configurations (indicating the range at which fail-safe should be configured). FS Max (FSmax) is the maximum pilot pressure during the fail safe control mode, and FS Min (FSmin) is the minimum pilot pressure during the fail safe control mode. Further, fig. 6a shows that when the flow is kept constant, the pressure will vary depending on the feed current of the actuator. This means that when the feed current is below the threshold, the pressure will increase at a constant flow, creating a fail-safe damping characteristic (chosen somewhere within the range of FS max and FS min) corresponding to a particular feed current.
This function is also shown in fig. 6b, but the graph therein shows that for a constant current, the fluid pressure will increase with the fluid flow. Each of the three curves Imax, imaddle and imam (Imin) in fig. 6b represents the feed current of the actuator. Imax represents the maximum current fed to the solenoid as the top curve, e.g., 3.0A. For this current, the pressure will increase rather steeply (exponentially) at the beginning of the curve (typically during the discharge flow 20), after which the pressure increases with a relatively low linearity once the
Fig. 7 shows a side sectional illustration of a
Finally, fig. 8 illustrates a method for controlling the pilot pressure in the
While exemplary embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications or variations of the invention described herein may be made. Furthermore, the different embodiments described above may be combined in different ways without departing from the scope of the inventive concept. It is, therefore, to be understood that the foregoing description of the invention and the accompanying drawings are to be regarded as non-limiting examples thereof and that the scope of the invention is defined in the appended patent claims.
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