Solenoid Valve for Shock Absorber With Hydraulic Load Regulation

Abstract

A solenoid valve that can be adjusted axially, and hermetically, to a first end of a body of a shock absorber in order to be able to regulate the hydraulic load of the shock absorber as well as guide the movement of the rod in a longitudinal direction. The solenoid valve includes a movable part that can be moved between an open fluid flow position and another closed fluid flow position, a regulating chamber that generates a pressure to move said movable part towards the opening and an elastic element that generates a closing force. Likewise, the solenoid valve also includes electronic means to exert a force on the movable part, to move it in the direction of movement, preferably by means of a magnetic load. The invention also includes a shock absorber with hydraulic load regulation that comprises a solenoid valve, like the one mentioned, adjusted hermetically to a first end of the body of said shock absorber.

Claims

1. A solenoid valve for shock absorber with hydraulic load regulation, wherein said solenoid valve is configured to: be adjustable axially and hermetically, to a first end of a body of a shock absorber; and regulate the hydraulic load of a fluid that flows through the inside of the shock absorber; wherein the solenoid valve comprises a longitudinal hole, configured to guide and seal, in a longitudinal movement, a rod comprised in the shock absorber; wherein the solenoid valve comprises: a movable part that can be moved, preferably in a longitudinal direction, between a closed-end position and an open-end position; a regulating chamber configured to receive and release fluid from the body of the shock absorber; an elastic element configured to exert a load to move the movable part, in the direction of movement, in the direction of the open-end position towards the closed-end position of said movable part; wherein the regulating chamber is configured to increase an internal pressure upon receiving fluid from the body and transmit a force created by said internal pressure to the movable part; wherein the movable part is configured to move from the closed-end position to the open-end position upon receiving a specific pressure from the regulating chamber when said chamber raises the internal pressure; wherein the regulating chamber is configured to release fluid when the movable part has moved from the closed-end position to the open-end position; and wherein the solenoid valve comprises electronic means configured to exert a force to move the movable part in the direction of movement, upon receiving a control electric current, preferably by generating a magnetic load on said movable part.

2. The solenoid valve, according to claim 1, where the movable part comprises one or more hydraulic duct configured to direct the passage of fluid released by the regulating chamber, through an expansion chamber, towards a reserve chamber of the body of the shock absorber.

3. The solenoid valve, according to claim 2, where the solenoid valve comprises a controlled fluid leak that connects the regulating chamber to the expansion chamber.

4. The solenoid valve, according to claim 1, comprising a low-friction bushing arranged inside the solenoid valve, adjustable with clearance on the rod of the shock absorber, wherein said low-friction bushing is configured to guide the longitudinal movement of the rod.

5. The solenoid valve, according to claim 1, comprising a hydraulic seal arranged inside the solenoid valve, adjustable on the rod of the shock absorber, configured to seal, hermetically, said shock absorber.

6. The solenoid valve, according to claim 1, comprising a connection bushing, configured to be assembled to a longitudinal inner tube of the damping body, being adjusted with clearance to the rod of the shock absorber, where the adjustment with clearance between the connection bushing and the rod comprises a duct for passage of fluid from the inner tube to the regulating chamber.

7. The solenoid valve, according to claim 6, comprising a sealing element between the movable part and the connection bushing, configured to prevent leaks of fluid from the regulating chamber.

8. The solenoid valve, according to claim 6, comprising a disc, adjustable with clearance to the rod of the shock absorber, where said disc is assembled to the connection bushing, and wherein said disc acts as a stop for the movable part in the closed-end position.

9. The solenoid valve, according to claim 1, where the regulating chamber comprises an annular geometry concentric to the rod of the shock absorber to which the solenoid valve can be adjusted.

10. The solenoid valve, according to claim 8, where the annular geometry of the regulating chamber is delimited by the movable part, the connection bushing and the disc.

11. The solenoid valve, according to claim 1, where, with the solenoid valve being connected to the body of the shock absorber, the movable part is located blocking the expansion chamber of the shock absorber by a surface opposite a surface that is in contact with the regulating chamber.

12. The solenoid valve, according to claim 1, comprising a main valve, located adjacent to the regulating chamber, configured to transmit the force created by the pressure of the regulating chamber to the movable part, where said main valve comprises a portion subjected to the pressure of the regulating chamber, which can be regulated.

13. The solenoid valve, according to claim 1, where the electronic means comprise a coil configured to generate a magnetomotive force that creates a magnetic flux when said coil receives a control current; where said flux is configured to generate a load to move the movable part between the open-end position and the closed-end position; and where said movable part comprises a ferromagnetic material.

14. The solenoid valve, according to claim 1, comprising a rod guide that comprises a hole which comprises a section larger than the section of the rod of the shock absorber to which the solenoid valve can be connected, where said hole is arranged concentrically to the longitudinal path of the rod when the solenoid valve is connected to the body of the shock absorber.

15. The solenoid valve, according to claim 8, where the rod guide, the movable part and the disc each comprise a ferromagnetic material, and where the solenoid valve comprises a functional magnetic circuit that comprises an assembly formed by the coil, the rod guide, the movable part and the disc, said functional magnetic circuit being configured to exert a force on the movable part and control the movement of the movable part between the closed-end position and the open-end position, preferably in the longitudinal direction.

16. The solenoid valve, according to claim 1, where the elastic element comprises two or more different elastic stages, a first low-rigidity elastic stage and a second high-rigidity elastic stage.

17. The solenoid valve, according to claim 1, where the elastic element comprises an element selected from: a disc valve, a plurality of stacked disc valves, a helical spring, a wave spring, a disc spring, or a combination of the foregoing.

18. The solenoid valve, according to claim 1, comprising a modular element that comprises a cover joined to the electronic means, where said modular element can be assembled to the rest of the assembled components comprised in the solenoid valve, by means of a removable mechanical joint.

19. The solenoid valve, according to claim 1, where the modular element comprises a wired connection connected to the coil, where said wired connection is configured to connect, electronically, to the control means of the solenoid valve.

20. A shock absorber with hydraulic load regulation, comprising a solenoid valve, as defined in claim 1, adjusted axially, and hermetically to a first end of a body comprised in said shock absorber, where said shock absorber comprises a rod that can be moved longitudinally inside the body, said rod passing through the longitudinal hole of the solenoid valve.

21. The shock absorber, according to claim 20, where the rod comprises a piston subassembly, connected to a lower end portion of said rod, and which is located inside the body, sharing longitudinal movement with said rod, where said piston subassembly comprises one or more assembled piston valves that comprise configurable rigidity and pre-deformation.

22. The shock absorber, according to the claim 21, where the piston subassembly comprises a controlled permanent leak.

23. The shock absorber, according to claim 21, where the body of the shock absorber comprises: an inner tube assembled, by an upper end portion of said inner tube, to the solenoid valve, said inner tube configured to house the rod during its longitudinal movement; an outer tube assembled, by an upper end portion of said outer tube, to the solenoid valve, the inner tube being located inside the outer tube; where the inner tube comprises a lower chamber located between a lower end portion of said inner tube and the piston subassembly of the rod; and an upper chamber located between the piston subassembly of the rod and the solenoid valve; and where the shock absorber comprises a reserve chamber and an expansion chamber located between the inner tube and the outer tube; and where the solenoid valve is configured to limit the passage of fluid of the shock absorber between the chambers of the inner tube to the chambers of the outer tube.

24. The shock absorber, according to claim 23, comprising an intermediate tube located between the inner tube and the outer tube, configured to direct the fluid of the shock absorber from the solenoid valve to a lower portion of the reserve chamber.

25. The shock absorber, according to claim 20, comprising a valve support subassembly adjusted hermetically, to a second end of the body, where the valve support subassembly comprises one or more assembled support valves that comprise configurable rigidity and pre-deformation.

26. The shock absorber, according to claim 20, comprising a complementary solenoid valve adjusted hermetically to a second end of the body comprised in said shock absorber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] The terms Fig., Figs., Figure, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings.

[0092] To complement the following description and for the purpose of helping to better understand the features of the invention, a set of drawings is attached to the present specification, in the figures of which the most characteristic details of the invention are represented by illustration and not limitation.

[0093] FIG. 1A shows an elevation view, sectioned in half, of the shock absorber comprising a solenoid valve connected to the first end of the body of the shock absorber, in its simplest configuration, the piston subassembly of the rod being in a longitudinal intermediate position inside the inner tube, and a valve support subassembly connected to a second end of the body, by the lower end portions of the inner and outer tubes.

[0094] FIG. 1B shows a view similar to the view shown in FIG. 1A, where the shock absorber comprises two solenoid valves, where the complementary solenoid valve replaces the valve support subassembly of FIG. 1A, connected to the second end of the body.

[0095] FIG. 1C shows a detailed view of the solenoid valve in FIG. 1A that clearly represents each of the components of the solenoid valve as well as its arrangement.

[0096] FIG. 2A shows the same view of the shock absorber shown in FIG. 1A, where the flow of the fluid of the shock absorber can be observed, in an extension movement of the rod, with respect to the body of the shock absorber, where the solenoid valve is in an open state, i.e., with the movable piece longitudinally moved from the closed-end position.

[0097] FIG. 2B shows the same view of the shock absorber shown in FIG. 1A, where the flow of the fluid of the shock absorber can be observed, in a compression movement of the rod, with respect to the body of the shock absorber, where the solenoid valve is in an open state, i.e., with the movable piece longitudinally moved from the closed-end position.

[0098] FIG. 3 shows a detailed view of the solenoid valve as shown in FIG. 1C, which comprises a sealing element located between the movable part and the connection bushing.

[0099] FIG. 4A shows a detailed view of the solenoid valve as shown in FIG. 1C, which comprises a main valve between the movable part and the regulating chamber, where the solenoid valve is closed, i.e., with the movable part in the closed-end position.

[0100] FIG. 4B shows a detailed view of the solenoid valve as shown in FIG. 1C, which comprises a main valve, where the solenoid valve is open, i.e., where the movable part is moved from the closed-end position to the open-end position, the main valve exerting a lever effect due to the pressure load generated in the regulating chamber.

[0101] FIG. 4C shows a detailed view of the solenoid valve as shown in FIG. 4A, i.e., where the solenoid valve is closed, the main valve comprises an increase in outer diameter and said main valve avoids direct contact of the oil exiting the regulating chamber with the movable part in case it moves from the closed-end position.

[0102] FIG. 5 shows a detailed view of the solenoid valve as shown in FIG. 1C, where the elastic element has variable rigidity since it comprises a stack of valves with an opening limiting valve.

[0103] FIG. 6 shows the same view of the shock absorber shown in FIG. 1A, which comprises an intermediate tube between the inner tube and the outer tube, which allows the fluid of the shock absorber to be directed from the regulating chamber of the solenoid valve to a lower portion of the reserve chamber.

[0104] FIG. 7 shows a view of the shock absorber, where the modular element, which comprises the cover with the electronic means, which in turn comprise a coil, is partially assembled with the rest of the components of the solenoid valve, showing its modular nature.

[0105] FIG. 8 shows a view of the shock absorber similar to that shown in FIG. 7, where the modular element is fully inserted into the rest of the components of the solenoid valve but comprising a connector fixed on the cover instead of a wired connection, connected to the coil of the electronic means.

[0106] FIG. 9A shows a diagram that relates the hydraulic load (C.sub.H) of the shock absorber on the Y-axis with the movement speed of the rod (V.sub.DV) on the X-axis. The positive portion of the hydraulic load (C.sub.H) (Y-axis) shows the different damping loads for the extension (E) of the rod, and the negative portion shows the loads for the compression (C), being able to have infinite loads or damping laws due to the infinite different levels of force that can be exerted on the movable part in the movement that it can undergo due to the effect of the coil of the electronic elements.

[0107] FIG. 9B shows a diagram that represents the movement (D) of the movable part in a longitudinal direction on the X-axis, and the force (F) applied on said movable part on the Y-axis, representing three lines. A curved line that shows how the magnetic force (F.sub.M) decreases as the movable part moves away from the electronic elements, a straight line that shows how the force of the elastic element (F.sub.EE) increases linearly as the movable part moves away from the closed-end position, and a line that shows the total force (F.sub.T), the sum of both previous lines.

[0108] FIG. 9C shows a diagram similar to the diagram shown in FIG. 9B, where the elastic element comprises two different elastic stages, a first low-rigidity elastic stage and a second high-rigidity elastic stage.

LIST OF REFERENCE NUMBERS SHOWN IN THE FIGURES

[0109] 1. Solenoid valve [0110] 2. Body [0111] 3. Rod [0112] 4. Wired connection [0113] 5. Piston subassembly [0114] 51.Piston valves [0115] 6. Valve support subassembly [0116] 61.Support valves [0117] 7. Connector [0118] 8. Fluid [0119] 9. Shock absorber [0120] 10. Disc [0121] 11. Cover [0122] 12. Coil [0123] 13. Movable part [0124] 131. Hydraulic duct [0125] 14. Regulating chamber [0126] 15. Elastic element [0127] 16. Low-friction bushing [0128] 17. Main valve [0129] 18. Hydraulic seal [0130] 19. Rod guide [0131] 20. Inner tube [0132] 21. Outer tube [0133] 22. Lower chamber [0134] 23. Upper chamber [0135] 24. Reserve chamber [0136] 25. Expansion chamber [0137] 26. Intermediate tube [0138] 27. Sealing element [0139] 28. Connection bushing [0140] 29. Complementary solenoid valve [0141] (C.sub.H) Hydraulic load [0142] (V.sub.DV) Movement speed of the rod in the longitudinal direction [0143] (E) Rod extension [0144] (C) Rod compression [0145] (D) Movement of the movable part [0146] (F) Force applied on said movable part [0147] (F.sub.M) Magnetic force applied by the electronic means [0148] (F.sub.EE) Force of the elastic element [0149] (F.sub.T) Total sum of the force of (F.sub.M) and (F.sub.EE) [0150] (C.sub.ME) Maximum load in extension [0151] (C.sub.mE) Minimum load in extension [0152] (C.sub.mC) Minimum load in compression [0153] (C.sub.MC) Maximum load in compression.

DESCRIPTION OF THE INVENTION

[0154] FIG. 1A shows a shock absorber (9), object of the invention, which comprises a body (2), a rod (3) and a solenoid valve (1), also object of the invention, adjusted or assembled, hermetically, to a first end of the body (2).

[0155] Said FIG. 1A also shows that the body (2) of the shock absorber (9) comprises two tubes: an outer tube (21) and an inner tube (20) located in an internal cavity of the outer tube (21), both being cylindrical and arranged concentrically.

[0156] The shock absorber (9) comprises a usual shock absorber arrangement, such as those existing on the market, which comprises a rod (3), movable in a longitudinal direction inside the body (2), specifically inside the inner tube (20), both being positioned concentrically, said rod (3) comprising a cylindrical bar shape with two ends. A lower end portion of said rod (3) is connected to a piston subassembly (5), which is always inside the inner tube (20), while the opposite end portion, the upper one, is outside and configured to connect to the element to be damped, such as the structure of a vehicle.

[0157] The piston subassembly (5) of the rod (3) divides the internal cavity of the inner tube (20) into two parts. A lower chamber (22) and an upper chamber (23) such that when the rod (3) moves longitudinally with respect to the body (2), a fluid (8), preferably oil, contained inside said chambers (22, 23) can pass in a regulated manner, from one to the other, through piston valves (51), located in the piston subassembly (5), generating a pressure difference between both faces of the piston, which results in a specific load. In other words, the hydraulic load of the shock absorber will be determined, in part, based on the permitted flow regime of fluid (8) through said piston valves (51).

[0158] This piston subassembly (5) is similar to those existing in the state of the art where the series of piston valves (51) define its characteristic operation. It may or may not incorporate a controlled permanent leak and the assembled valves have a configurable rigidity and pre-deformation.

[0159] Between the inner tube (20) and the outer tube (21) is a reserve chamber (24) that houses fluid (8) and is connected to the lower chamber (22) of the inner tube (20), in one embodiment, by means of a valve support subassembly (6) which in turn comprises support valves (61). This valve support subassembly (6) is assembled or adjusted, hermetically, to a second end of the body (2), to both tubes (20, 21).

[0160] When the rod (3) moves longitudinally with respect to the body (2), as an extension, the fluid (8) contained in the reserve chamber (24) can pass through the support valves (61) towards the inside of the lower chamber (22), in a regulated regime.

[0161] This valve support subassembly (6) is also similar to those existing in the state of the art, as well as the support valves (61) that define its operation. Likewise, it may or may not incorporate a controlled permanent leak and the assembled support valves (61) have a configurable rigidity and pre-deformation.

[0162] The configuration of the piston and the valve support will be oriented so that, in the extension and/or compression movement of the rod (3), the oil is forced to pass through the solenoid valve (1), which allows the hydraulic load (C.sub.H) of the shock absorber (9) to be adapted at each instant.

[0163] Since the reserve chamber (24) is not completely filled with fluid (8), the upper portion of the cavity comprised between the inner tube (20) and the outer tube (21) is occupied by an expansion chamber (25) configured to house gas from inside the shock absorber (9).

[0164] In order to obtain a hydraulic load (C.sub.H) that can be regulated in the shock absorber (9), which is the objective of the invention, the shock absorber (9) comprises at least one solenoid valve (1) as shown in FIGS. 1A, 1B and, in detail, 1C.

[0165] These figures show how said solenoid valve (1) comprises a wired connection (4) which can transmit a control current from the outside to the solenoid valve (1) to determine the desired flow of fluid (8) between the upper chamber (23) and the reserve chamber (24), through the expansion chamber (25), which allows the exact hydraulic load (C.sub.H) to be determined at each instant, taking into account the configuration of the rest of the elements of the shock absorber (9), such as the support valves (61) and the piston valves (51).

[0166] In addition to allowing a regulated flow of fluid (8), the solenoid valve (1), being connected axially and hermetically to the first end of a body (2) of the shock absorber (9), also performs the guide and sealing functions of the rod (3) in its longitudinal movement with respect to the body (2), this being a feature that does not exist in lateral connection solenoid valves. Likewise, its axial connection on the body (2), by advantageously using the available space and thereby achieving greater magnetic forces, allows the solenoid valve (1) to not require a hydraulic amplification mechanism to provide different hydraulic loads to the shock absorber (9), as the lateral connection solenoid valves do.

[0167] FIG. 1C shows that there is a low-friction bushing (16) inside the solenoid valve (1) and it performs the guiding function of the rod (3), also serving as support when said rod is subjected to lateral forces.

[0168] In addition to said low-friction bushing (16), the solenoid valve (1) also comprises a rod guide (19) that comprises a hole with a constant section slightly larger than the section of the rod (3). Said hole is arranged concentrically to the longitudinal path of the rod (3) and allows the rod guide (19) to delimit its path. In the same way, the low-friction bushing (16), which is fitted into the rod guide (19), delimits the path of the rod (3) together with the rod guide (19) or independently.

[0169] The hydraulic sealing function of the rod (3) with respect to the body (2) of the shock absorber (9), usually carried out by a gasket, is carried out by a hydraulic seal (18) comprised inside the solenoid valve (1).

[0170] To regulate the hydraulic load of the shock absorber (9), the solenoid valve (1) mainly comprises a movable part (13) that can be moved, according to the embodiment shown in the figures, in a longitudinal direction, which acts as a passage gate for the fluid (8) inside the solenoid valve (1). This movable part (13) can move between a closed-end position and an open-end position, and can be placed in infinite intermediate positions between both ends. For example, in FIG. 1C, the movable part (13) is in a closed-end position and in FIG. 4B it is moved from said position to the open-end position, allowing the passage of the fluid (8) through the solenoid valve (1).

[0171] The solenoid valve (1) also comprises a series of elements or devices configured to move the movable part (13): a regulating chamber (14), configured to receive and release fluid (8) from the body (2) of the shock absorber (9), specifically from the upper chamber (23) towards the reserve chamber (24), passing through the expansion chamber (25), (depending on the position of the movable part); an elastic element (15), configured to move the movable part (13), in the direction of movement, in the direction of the open-end position towards the closed-end position of said movable part (13); and electronic means configured to move the movable part (13), also in the direction of movement, in the same direction as the elastic element (15), for example, when a coil (12) receives a control electric current, generating a magnetic force (F.sub.M) on said movable part (13), preferably an attraction load.

[0172] As shown in FIGS. 2A and 2B, the operation of the solenoid valve (1) consists of, when the rod (3) moves longitudinally with respect to the body (2) of the shock absorber (9), the regulating chamber (14) receiving fluid from the upper chamber (23) which generates an increased internal pressure that transmits it to the movable part (13). Said movable part (13) begins to move from the closed-end position to the open-end position when the pressure exerted by the regulating chamber (14) exceeds a specific pressure.

[0173] Said specific pressure is defined by the configuration of the elastic element (15) and the electronic means which exert a force in a direction opposite to the force exerted by the hydraulic pressure of the regulating chamber (14) on the movable part (13).

[0174] In this way, once the rod (3) moves fast enough to move the fluid (8) from the upper chamber (23) towards the solenoid valve (1) with a high pressure, said fluid (8) being directed at said high pressure towards the regulating chamber (14), reaching a pressure limit higher than that exerted by the elastic element (15) and the electronic means, the movable part (13) moves towards the open-end position.

[0175] Once the movable part (13) has moved from the closed-end position, as shown in FIGS. 2A and 2B, the regulating chamber (14) releases fluid (8) through one or more hydraulic ducts (131) of said movable part (13), directing said fluid (8), after passing through the expansion chamber (25), towards the reserve chamber (24) contained in the body (2) of the shock absorber (9).

[0176] As shown in FIG. 1C, the solenoid valve (1) is connected to the first end of the body (2) of the shock absorber (9), specifically to the inner tube (20), by means of a connection bushing (28), which is adjusted with clearance to the rod (3). Said adjustment with clearance comprises a duct for passage of fluid (8) from the inner tube (20) to the regulating chamber (14), which is the one that connects the upper end of the upper chamber (23), which is filled with oil, to the regulating chamber (14).

[0177] As also shown in FIG. 1C, to avoid the loss of fluid (8) in the shock absorber, the solenoid valve (1) comprises the hydraulic seal (18) adjusted to the rod (3) that tightly seals the upper chamber (23), said seal (18) being attached to the rod guide (19).

[0178] As shown in FIG. 3, the solenoid valve (1) can also comprise a sealing element (27) between the movable part (13) and the connection bushing (28), which prevents an uncontrolled leak of oil from the regulating chamber (14).

[0179] This regulating chamber (14) can have different geometries depending on the configuration of the shock absorber (9). For example, an appropriate geometry is an annular geometry, or also a geometry of holes or windows made through a disc part (10).

[0180] Said disc part (10) is comprised inside the solenoid valve (1), being adjustable with clearance to the rod (3) of the shock absorber (9). This disc (10) is assembled to the connection bushing (28) and acts as a stop for the movable part (13) in the closed-end position. In other words, it prevents the movable part (13) from moving beyond said closed-end position, despite the loads exerted by the electronic means and by the elastic element (15). Since it is a part near the movable piece (13), openings or windows that function as a regulating chamber (14) can be made.

[0181] FIG. 1C also shows that the annular geometry of the regulating chamber (14) is delimited by the movable part (13), the connection bushing (28) and the disc (10). In this way, it is understood that the movable part (13) can move longitudinally, from the closed-end position to the open-end position, due to the difference in pressures to which it is subjected. On the one hand, the movable part (13) is in contact with the regulating chamber (14) and on an opposite surface, it is located blocking an expansion chamber (25) of the shock absorber (9).

[0182] Instead of closing the regulating chamber (14) directly with the movable part (13), the solenoid valve (1) may comprise a main valve (17), located adjacent to said regulating chamber (14), being configured to transmit the force created by the pressure of the regulating chamber (14) to the movable part (13), as shown in FIGS. 4A to 4C. Said main valve (17) comprises a portion subjected to the pressure of the regulating chamber (14), which can be regulated. This pressure will create a downward force that will be transferred to the movable part (13) in its opening movement. The portion of the main valve (17) that is subjected to pressure can be regulated in order to obtain different operating ranges of the loads of the shock absorber (9).

[0183] Likewise, main valves (17) of different outer diameters and thicknesses can be selected, which influence the transfer of the force to the movable part (13) from the regulating chamber (14). Said main valve (17) can also be configured with a controlled pre-deformation if desired for reasons of minimum load or closing quality. In fact, a controlled leak that connects the regulating chamber (14) to the expansion chamber (25) can be provided.

[0184] As indicated, the pressure that reaches the regulating chamber (14) is applied to the movable part (13). Said pressure creates a force that tends to move said movable part (13) so that the fluid (8) exits the regulating chamber (14), to relieve the hydraulic pressure. However, and as indicated, a series of forces also act on the movable part (13), which tend to close it and thus make it difficult to open. These forces are those generated by the elastic element (15) and by the electronic means, where the magnetic force (F.sub.M) is what determines the regulation of the hydraulic load (C.sub.H) of the solenoid valve (1).

[0185] As shown in FIG. 1C, the movable part (13) is pushed, on its lower face, by one or a series of elastic elements (15), so that the exerted force is transmitted in a way that guarantees the closure of the solenoid valve (1) in the absence of other forces.

[0186] Likewise, the electronic means of the solenoid valve (1) comprise a coil (12) or solenoid capable of generating a magnetomotive force that creates a magnetic flux on some parts inside the solenoid valve (1), when said coil receives a control current. Said flow allows the movable part (13) to move between the open-end position towards the closed-end position, by generating a magnetic force (F.sub.M) of attraction on the movable part (13), since said movable part (13) comprises a ferromagnetic material. In other words, the generated magnetic force (F.sub.M) tends to push the movable part (13) so that it closes the regulating chamber (14) through the attraction of elements such as the rod guide (19) and the disc (10) also made of a ferromagnetic material.

[0187] Therefore, the opening pressure of the solenoid valve is controlled by regulating this magnetic force (F.sub.M) created on the movable part (13), which throttles and closes the passage of fluid (8) from the regulating chamber (14). Since said magnetic force (F.sub.M) is variable according to a control current provided to the coil (12), infinite hydraulic loads (C.sub.H), as shown in FIG. 9A, of both compression and extraction of the rod (3) are available.

[0188] As shown in FIGS. 9B and 9C, the magnetic force (F.sub.M) created by the electronic means on the movable part (13) is reduced as said movable part (13) moves from the closed-end position to the open-end position, since the force of attraction is reduced the further away the piece to be attracted is; however, this decrease is offset by the increase in the force of the elastic element (F.sub.EE).

[0189] If the main valve (17) has been arranged in the regulating chamber (14), the magnetic force (F.sub.M) created on this movable part (13) is applied to the main valve (17), given that this main valve (17) is the upper support of the movable part (13). This force can be applied to the outer diameter of the valve, but also to any other diameter if desired.

[0190] If necessary, controlled channels can be provided to ensure the correct lubrication of the movable elements present in the shock absorber (9), as well as the discharge of gas that may flow to this area, towards the expansion chamber (25).

[0191] As shown in FIG. 5, and unlike FIGS. 4A-4C, the elastic element (15) can comprise two or more different elastic stages, a first low-rigidity elastic stage and a second high-rigidity elastic stage. Given this configuration, a low rigidity can be available for small openings, but its rigidity can be increased for larger openings. Thus, when the system has large openings, there is a greater force that tends to close the solenoid valve (1), which may be suitable for preventing the appearance of vibrations from certain operating speeds of the shock absorber (9) that cause undesired large openings of the solenoid valve (1).

[0192] FIG. 7 shows that the solenoid valve (1) can comprise a modular configuration, where the cover (11) together with the electronic means comprise a module that can be assembled to the body (2) of the shock absorber (9), where the rest of components of the solenoid valve (1) are already assembled. This configuration facilitates the configuration of the solenoid valve (1) to prevent the electronic means from coming into contact with damping or lubrication fluids that could damage its state or hinder its operation.

[0193] As indicated and as shown in FIG. 7, the cover (11) is joined to a wired connection (4) which is connected to the electronic means, said wired connection (4) being configured to connect, electronically, to the control means of the solenoid valve (1). However, in a different embodiment, as shown in FIG. 8, the cover (11) may comprise a connector (7) fixed on the cover (11) instead of a wired connection (4), also connected to the coil (12) of the electronic means. This connector (7) can allow for a wireless connection of the shock absorber (9) with the control system.

[0194] In another embodiment, as shown in FIG. 6, the shock absorber (9) may comprise an intermediate tube (26) located between the inner tube (20) and the outer tube (21), to direct the fluid (8) to the reserve chamber (24) so that said fluid (8) is prevented from circulating through the expansion chamber (25) (which is full of gas), thus preventing an unwanted mixture of air and oil, which can cause foaming.

[0195] In another non-preferred embodiment, the shock absorber (9) may comprise a complementary solenoid valve (29) adjusted, hermetically, to a second end of the body (2) of the shock absorber (9), in addition to the solenoid valve (1) connected to the first end, as shown in FIG. 1B. So that the passage of fluid (8) through both ends of the fluid is regulated at all times.

Operation of the Shock Absorber with a Solenoid Valve

[0196] When the shock absorber (9) begins an extension movement (E), the fluid (8) (oil) in the upper chamber (23) is compressed, increasing its pressure. Since the volume of the upper chamber (23) decreases, the fluid (8) must exit said chamber. If the pressure is lower than the opening pressure of the solenoid valve (1), said valve is closed; therefore, the fluid (8) will flow through the piston subassembly (5) and pass through the controlled leak that has been configured in said piston subassembly (5), in that of the solenoid valve (1), or through both.

[0197] Thus, by means of the fixed configuration of the leak of the piston subassembly (5) and/or of the solenoid valve (1), a series of pressure drops are created in the upper chamber (23), since the fluid (8) passes through the aforementioned hydraulic ducts. The pressure resulting from the fluid (8) in said chamber, different from the pressure in the lower chamber (22), each applied to its corresponding face of the piston, creates the load of the shock absorber.

[0198] In this way, the hydraulic load of the shock absorber (9) is defined at low movement speeds of the rod (3) in extension (E), since the low speeds create pressures lower than the opening pressure of the solenoid valve (1). This type of control at low speeds of the rod (3) is used to improve the stability of the vehicle.

[0199] For faster movement speeds of the rod (3), the pressure continues to increase until reaching the opening pressure of the solenoid valve (1). When the pressure existing in the regulating chamber (14) is high enough to overcome the forces that close the movable part (13) on said chamber, this movable part (13) moves so that the solenoid valve (1) remains open, establishing a flow of fluid (8) that comes from the upper chamber (23) and ends in the reserve chamber (24), after passing through the expansion chamber (25).

[0200] Since the opening pressure of the solenoid valve (1) is regulated through the magnetic force (F.sub.M) created on the movable part (13), the pressure level from which the fluid (8) is allowed to flow through the open solenoid valve (1) is controlled, thus controlling the pressure in the upper chamber (23), thus generating the load of the shock absorber.

[0201] By advantageously using the existing space system, such as the coil (12) having been arranged in the area of the shock absorber guide, a magnetic force large enough to be able to directly handle the pressure existing in the regulating chamber (14) is obtained, without having to have an amplification stage, as is common in other types of systems that offer continuous regulation of the hydraulic load.

[0202] When the solenoid valve (1) opens, the movable part (13) slides and increases its distance with respect to the disc (10), so that according to the laws of magnetism, the magnetic force (F.sub.M) that the movable part (13) undergoes decreases. This drop in force is offset by the elastic element (15) located on the lower face of the movable part (13), so that when said part lowers, said elastic element (15) is pressed, creating force and stabilising the movable part (13).

[0203] FIG. 9B shows an example of the total force that the movable part (13) undergoes depending on its opening, where said total force (F.sub.T) equals the sum of the magnetic force (F.sub.M) plus the force exerted by the elastic element (F.sub.EE). The resulting curve of total force (F.sub.T) can be configured from the other two forces, so that it has the desired shape, which is important to determine the hydraulic behaviour of the shock absorber (9).

[0204] An advantageous arrangement, shown in FIG. 9C, can be a rigidity of the elastic element (15) in two stages, so that the rigidity is low for small openings, but its rigidity is increased for larger openings, so that when the system has large openings, there is a greater force that tends to close the solenoid valve (1), which may be suitable for preventing the appearance of vibrations from certain operating speeds of the shock absorber that cause large openings of the solenoid valve.

[0205] In a compression movement of the shock absorber (9), the operation is very similar to that of opening or extension, with the fluid (8) passing through the piston subassembly (5) and through the valve support subassembly (6). In this way, when moving at low speeds, the solenoid valve (1) does not open, but at higher speeds, a sufficiently high pressure is generated in the regulating chamber (14) to move the movable part (13) towards the open-end position.