Shock absorber with multiple damping control laws

Abstract

The present invention relates to a shock absorber with multiple damping control laws, comprising a regulating body (12) having a primary valve (14) and a secondary valve (15) and a drive shaft (21) having multiple flow passages (16, 17), the drive shaft (21) being accommodated in an axial orifice (36) of a piston pin (30) having multiple orifices (31, 32, 33) intended to be aligned with the flow passages (16, 17) by the rotation of the drive shaft (21) and to determine the damping control law, and the second orifice (32) is in direct communication with the regulating body (12), the regulating body (12) comprising a floating piston (13) having an annular configuration and made of elastic material, which gradually transmits a force to the primary valve (14) depending on the pressure it receives.

Description

[Technical field]

[0001] The present invention relates to a shock absorber capable of generating several damping control laws in order to adapt the damping of a device, usually a vehicle but which can be any kind of mechanism, to the requirements of its driving situation, which can be modified manually by the driver or operator himself or automatically by a computer, so that for each moment the most appropriate damping control law is selected and thus the shock absorber is adapted to the requirements of the driving situation of the device.

[0002] The shock absorber is particularly applicable in the field of hydraulic systems, in particular in the field of shock absorbers for vehicles. [Background technology]

[0003] A shock absorber is a device intended to damp suspension vibrations by dissipating kinetic energy until said suspension regains its equilibrium position. A very common development case focuses on vehicle applications.

[0004] Focused on the automotive sector, the shock absorbers have a decisive influence on both stability and comfort: in practice, the adjustment of the hydraulic load they generate represents a compromise between both factors. - in terms of stability, the dynamic control of the vehicle is achieved with low suspension extension / retraction speeds and low vibration frequencies corresponding to the natural frequency of the sprung mass (cabin), which for passenger cars is typically in the range of 1-2 Hz. This driving situation requires a high level of damping, i.e. high hydraulic loads; -For comfort, control is mainly concerned with medium and high suspension extension / retraction rates which occur at medium and high vibration frequencies. The reference frequency is the natural frequency of the unsprung mass (wheel / suspension), which is typically in the range of 8-15 Hz for passenger cars. Comfort is further enhanced by reducing the damping level and decoupling the wheel motion from the chassis vibrations.

[0005] It is therefore desirable to have a shock absorber whose load level can be adjusted to suit the characteristics of the vibration to be damped.

[0006] Conventional shock absorbers provide variable damping characteristics based on speed, which are pre-determined and not adaptable by the user or computer. This is the fundamental reason why there is a trade-off between comfort and stability that must be addressed when tuning the desired damping control law for a particular vehicle suspension. This is an optimization exercise to find the best compromise for the characteristics that the vehicle should have.

[0007] On the one hand, if the vehicle is designed to be comfortable, a low suspension damping level is selected so that the wheel movements are isolated as much as possible from the vehicle body, thus minimizing the transmission of road irregularities to the passenger compartment.

[0008] On the other hand, if a vehicle emphasizes stability, then the suspension is configured with high damping levels to minimize body movement.

[0009] The improvement over conventional shock absorbers consists in being able to adapt the load level depending on the desired objective at the time and being able to select between various possibilities of damping control laws depending on whether it is desired to change between higher stability and higher comfort.

[0010] In the current state of the art, different systems exist that are able to provide multiple damping control laws in a single shock absorber. These systems are usually based on solenoid valves that can be controlled by linear actuators (solenoids) or rotary actuators (motors).

[0011] A technical solution usually found in the state of the art, especially in low-cost systems, is to incorporate a second piston, controlling the oil flow through a passage connecting the two chambers separated by the first piston, generating two damping control laws: hard and soft.

[0012] In the hard control law, the oil flow through the passage is closed, while in the soft control law, the oil flow through the passage is open, which is controlled by the configuration of the secondary piston. With this working principle, it is possible to generate three or four damping control laws simply by gradually adjusting the passage cross section that the solenoid valve opens.

[0013] However, having a secondary piston comes with a series of drawbacks.

[0014] On the one hand, it is necessary to incorporate a series of passive elements in the secondary piston that allow the fluid flow to be adjusted / varied, which means an increase in the number of elements, leading to higher costs and the need for axial space.

[0015] On the other hand, the flow passage constructed as an orifice in the rod pin must have a significant flow cross section in order to achieve a low damping control law, which requires an increase in the diameter of the rod pin, resulting in an increase in the radial dimensions of the system, which makes it difficult to implement. In addition, the large diameter of the pin requires the use of specific large pistons, valves, washers and nuts, which also leads to an additional increase in the cost of the product.

[0016] The document US 4953671A shows a shock absorber which can be operated under different control laws by driving a control pin 31 attached to a shaft 30 rotatably inserted in the rod 7 of the piston 5. The shaft 30 is provided with three longitudinal grooves 33, 34, 35 on its circumference which, depending on the position of the shaft 30, create different communication between the upper chamber 3, the lower chamber 4 and the pressure chambers 15, 16, so that the shock absorber behaves according to a soft damping control law, if the communication between the lower chamber 4 and the upper chamber 3 is direct, or according to a hard damping control law, if the communication is via the pressure chambers 15, 16.

[0017] The first groove 33 has a length such that at one end it communicates with the upper chamber 3 through a first orifice 36 in the rod 7 of the piston 5 and at the other end it communicates with a second orifice 37 in the rod 7 of the piston 5 which communicates with a pressure chamber 16 separated from the lower chamber 4 through a valve 12 having an orifice 14.

[0018] The second groove 34 is located radially opposite to the first groove 33, and has a length such that one end communicates with a third orifice 39 in the rod 7 of the piston 5 which communicates with a pressure chamber 15 separated from the upper chamber 3 via the valve 13, and the other end communicates directly with the lower chamber 4.

[0019] The third groove 35 puts the upper chamber 3 in direct communication with the lower chamber 4 by means of an orifice 41 in the rod 7 of the piston 5 .

[0020] In the invention, the hard control law is obtained by transmitting pressure from the upper chamber 3 to chamber 16 in order to increase the damping in the extension motion, and from the lower chamber 4 to chamber 15 in the compression motion. The shaft 30, by rotating in the opening of the rod 7, serves to enable said transmission in the hard control law and to nullify it in the soft control law. However, this rotation requires a clearance with the opening of the rod 7, so that a certain pressure transmission is allowed even in the soft control law if no additional sealing system is provided. The pressure transmitted to the chambers 15 and 16 acts directly on the valves 12 and 13, so that a certain force increase occurs even in the soft control law.

[0021] Another limitation of the present invention is that it can only generate two damping control laws: soft and hard, and in addition, as explained in the previous paragraph, the force difference between the two may not be very large and may show a large variability depending on the clearance between the shaft 30 and the opening of the rod 7.

[0022] Similarly, the direct action of pressure transmitted from chambers 3 and 4 to valves 12 and 13 in the hard control law results in a nearly instantaneous increase in damping force. This direct response lacks gradual force application, leading to greater presence of acceleration peaks in the chassis as well as increased noise. Both effects limit the ability to maintain adequate comfort levels in the hard control law. Summary of the Invention [Means for solving the problem]

[0023] As stated above, the present invention relates to a shock absorber capable of generating multiple damping control laws to adapt the damping of the system to the demands of its driving conditions.

[0024] Thus, the present invention describes a shock absorber with multiple damping control laws, comprising an adjusting body with a primary valve and a secondary valve, the shock absorber also comprising a drive shaft housed in a piston pin and driven manually or automatically, the function of which is to select, depending on its position, located by rotation, either automatically via an actuator or manually via a rod, a damping control law determined as described herein.

[0025] In the case of automatic actuation, the actuator comprises a body housed in a rod with a drive shaft attached to the rod, the drive shaft protruding from the rod to be housed in an axial orifice formed in the piston pin, fixed to the rod as an extension and passing through the piston through an axial orifice provided therein.

[0026] It is common for a shock absorber rod to be understood as comprising its own body and a piston pin, however, in this case it should be noted that these two components are independent and the rod and piston pin are considered as separate entities, with the piston pin being attached to the rod to accommodate the body of the actuator.

[0027] The drive shaft has multiple passages while the piston pin has multiple inlet and outlet orifices that connect the two chambers of the shock absorber. These orifices allow the fluid to enter or exit as the fluid flow direction changes whether the shock absorber is in extension or compression. The alignment of the orifices with the passages allows for the circulation of the shock absorber fluid, which determines the damping control law that the shock absorber will follow at that time.

[0028] The orifice in the piston pin contains: a first orifice communicating the expansion-side chamber with an axial orifice of the piston pin; - a second orifice that communicates between the axial orifice of the piston pin and the compression side chamber through an adjustment body; and a leakage orifice located in the piston pin and rotated relative to the first orifice, communicating the expansion chamber with an axial orifice of the piston pin;

[0029] On the other hand, the flow passage of the drive shaft includes: a first flow passage having a length communicating the first orifice with the second orifice; a second passage having a length communicating the first orifice with an opening at the end of the axial orifice of the piston pin;

[0030] The adjusting body defines a cavity having therein a floating piston having an annular configuration and made of elastic material, whereby the floating piston achieves a gradual movement of the primary valve in response to the pressure to which it is subjected, said movement resulting in a gradual blocking of the piston flow.

[0031] In this first embodiment in which the shock absorber comprises a single adjusting body, the piston pin can be provided with a second leakage orifice which is located as an extension of the leakage orifice but has a larger flow cross section.

[0032] In a second embodiment, the shock absorber can also include an additional adjustment body arranged in conjunction with the adjustment body, the adjustment body being connected to the second orifice, and the additional adjustment body being arranged below the second orifice and also connected to an additional second orifice communicating the axial orifice of the piston pin with the compression side chamber. In this case, the drive shaft also has a third passage having a length such that the first orifice communicates with the additional second orifice, and the piston pin has a third leakage orifice arranged as an extension of the first orifice and preferably having a significantly smaller passage cross section with the intention of achieving a harder damping control law.

[0033] The fact that the additional adjusting body is arranged in conjunction with the adjusting body, i.e. one following the other, means that the primary valve of the additional adjusting body is the secondary valve of the adjusting body, whereby the effect of the floating piston of the adjusting body is reinforced by the effect of the additional floating piston of the additional adjusting body.

[0034] The shock absorber can also have two adjusters, one on each side of the piston, so that the shock absorber can operate according to different damping control laws for both compression and extension.

[0035] The relationship between the orifices of the piston pin is preferably such that the second leakage orifice is larger than the first orifice, which is larger than the transverse orifice, which is in turn larger than the third leakage orifice, although in each case this is an advantageous configuration, other relationships are possible and functional, providing different damping control laws.

[0036] The shock absorber can also comprise a slide arranged between the flexible floating piston and the primary valve, which slide can slide along the piston pin and has the function of transmitting the force received from the floating piston to the primary valve with a configurable diameter and protecting the floating piston. The main purpose of introducing the slide as an intermediate element is to better protect the floating piston, thereby allowing it to operate at higher pressures.

[0037] On the other hand, the free end of the drive shaft may be provided with a longitudinal extension with a semicircular cross section, while the axial orifice may be provided with an end orifice with an elongated cross section eccentric to said drive shaft. In this way, the movement of the drive shaft is limited to a quarter turn, since the walls of the end orifice act as a mechanical stop together with the drive shaft extension, preventing its further rotation.

[0038] In this situation it is suggested to go a step further and say that the extension is a modified extension having a quarter circular cross section and in addition the shock absorber comprises a disk fixed to the end of the piston pin and having a semicircular orifice through which the modified extension passes, thereby limiting the free movement of the drive shaft to a quarter turn and allowing it to rotate a further quarter turn by dragging the disk.

[0039] In these cases, the shutoff system described above can have other configurations with respect to the cross-sectional geometry of the shaft and orifice to provide comparable constraints on operation.

[0040] In summary, the main advantages offered by the present solution can be considered as follows: - Simplicity: No secondary piston is required. A new piston valve design is provided, which allows direct modulation under load. The design is compatible with standard valve components. -Cost: The elimination of the secondary piston reduces components considerably. - Consumption: Rotary actuators (motors) consume less energy than linear actuators (solenoids) because energy is consumed only when changing from one position to another, and not to maintain the position. -Compactness: the drive shaft is directly connected to the motor or actuator, can be placed inside the rod and has very small dimensions, which, like the drive shaft, minimizes the load on its rotation. In the state of the art, the drive shaft is connected to the actuator via a control pin, which has a large diameter and the friction of the shaft in the piston pin orifice is also large, and therefore the opposing torque due to the friction of the shaft in the piston pin orifice is also large. This large opposition requires a stronger and larger actuator that cannot be accommodated inside the rod. - Standardized: the flow rate of fluid exchanged between the two chambers defined by the piston is low, since it is only used to modify the permanent leakage (low speed) and to supply the regulator (hard control law). This allows the use of a standard small diameter piston pin, and also allows standard pistons and valves as well, so that there is no need to oversize the elements. Conversely, in a double piston system, most of the flow rate displaced by the piston in its movement passes through the orifice of the piston pin, which must have a large diameter.

[0041] Furthermore, as an alternative to using a rotary motor as the actuator, the drive shaft can be manually actuated via a rod attached to the shaft and extending outside the rod of the shock absorber.

[0042] To complement the description of the present invention and to assist in making its features more readily comprehensible, a series of drawings are included in accordance with preferred exemplary embodiments thereof, which are for illustrative purposes and not limiting. The following drawings are represented: [Brief description of the drawings]

[0043] [Figure 1] Fig. 1(A) shows a longitudinal sectional view of a shock absorber of the present invention that is automatically driven for extension operation, and Fig. 1(B) shows a longitudinal sectional view of a shock absorber of the present invention that is manually driven from the outside for extension operation. [Diagram 2] Fig. 2(A) shows a longitudinal cross-sectional view of a shock absorber having an actuator for extending and retracting operation in a first embodiment. Fig. 2(B) shows a longitudinal cross-sectional view of a shock absorber having an actuator for extending and retracting operation in a second embodiment. [Figure 3A] FIG. 3A shows a longitudinal section of a detail in the area of ​​the piston of the shock absorber of FIG. 1A in a rest state in a first embodiment. [Figure 3B] FIG. 3B shows a longitudinal section of a detail in the area of ​​the piston of the shock absorber of FIG. 1A in a rest state in a second embodiment. [Figure 4] FIG. 4 shows the shock absorber of FIG. 3A operating according to a hard damping control law, together with an enlarged detail of the adjuster. [Figure 4A] FIG. 4A shows details of the adjustment body. [Diagram 5] FIG. 5 shows the shock absorber of FIG. 3A operating according to an intermediate damping control law. [Figure 6] FIG. 6 shows the shock absorber of FIG. 3A operating according to a soft damping control law. [Figure 7] FIG. 7 shows the shock absorber of FIG. 3A operating according to an ultra-soft damping control law. [Figure 8] FIG. 8 shows a second embodiment to FIG. 4, where the control law is hardened by modifying the orifice in the piston pin, adding a passage in the drive shaft, and using two adjusters. [Figure 9] FIG. 9 shows a second embodiment to FIG. 5, where the control law is hardened by modifying the orifice in the piston pin, adding a passage in the drive shaft, and using two adjusters. [Figure 10]FIG. 10 shows a second embodiment to FIG. 6, where the control law is hardened by modifying the orifice in the piston pin, adding a passage in the drive shaft, and using two adjusters. [Figure 11] FIG. 11 shows a second embodiment to FIG. 7, where the control law is hardened by modifying the orifice in the piston pin, adding a passage in the drive shaft, and using two adjusters. [Figure 12] FIG. 12 shows a graph illustrating the variation of damping force as a function of the piston velocity for the shock absorber of the invention shown in FIG. 1 for an extension motion. [Figure 13] FIG. 13 shows a graph illustrating the variation of damping force as a function of the piston speed for the shock absorber of the invention shown in FIG. 2 for extension and contraction movements. [Figure 14A] FIG. 14A shows the shock absorber of FIG. 3A according to an embodiment having a mechanical locking system and focusing on only two control laws. [Figure 14B] FIG. 14B shows an alternative embodiment of the locking system shown in FIG. 14A, in which a separate bushing and a rotation limiting plate are provided. [Figure 15] FIG. 15 shows the shock absorber of FIG. 3A according to an embodiment having a mechanical locking system and focusing on three control laws. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The present invention discloses a shock absorber that allows the selection of up to four different damping control laws, which can be actuated automatically or externally by manual means. For this purpose, the shock absorber comprises a drive shaft (21) attached to an actuator (20) connected to a connector by a cable (22) in the case of automatic selection, or directly to a mechanism (not shown) in the case of manual selection. The damping control laws are selected by simply rotating the drive shaft (21) to the appropriate position and hydraulically connecting the appropriate orifices (31, 32, 32', 33, 34, 35, 36) to the appropriate passages (16, 17, 18), as described below.

[0045] Both the connectors and the mechanisms are known in the state of the art and are attached to corresponding devices so that the selection of the appropriate damping control law can be made.

[0046] On the other hand, a two-cylinder shock absorber having an outer case (1) and an inner tube (2) in which a piston (4) is located is considered, but this can be extended to other types of shock absorbers such as a mono- or tri-cylinder shock absorber.

[0047] 1(A) and 1(B) show longitudinal cross-sectional views of a shock absorber of the present invention for automatically and manually selecting the damping control law for the extension operation, respectively, by providing an adjustment body (12) in the compression side chamber (6) of the shock absorber.

[0048] Next, FIG. 2(A) shows the shock absorber of FIG. 1(A) configured to provide multiple damping control laws for both extension and retraction motions by including a second adjustment body (12) positioned in the extension side chamber (5).

[0049] FIG. 2(B) shows a second embodiment of the shock absorber of FIG. 2(A) in which the communication between the adjustment body (12) and the expansion-side chamber (5) and the compression-side chamber (6) is changed.

[0050] There is no functional difference between these two embodiments. The embodiment of FIG. 2(A) is adapted to a standard double-acting (DA) piston, and the embodiment of FIG. 2(B) is adapted to a double-acting piston with radial holes (DAC). The difference between these two embodiments is in the radial orifices in the piston pin (30). In the second embodiment, the orifices for sucking oil into the adjusting body during the compression phase need more holes than in the first embodiment, since the oil is not sucked directly from the expansion side chamber (5) or the contraction side chamber (6) but from "below" the corresponding primary valve (14).

[0051] Figure 3A shows the components of the invention, namely the actuator (20) and the piston (4) area in more detail. As can be seen, the piston pin (30) has a first seal (26) with the drive shaft (21) and a second seal (27) with the rod (3). With these two seals (26, 27) an oil-protected leak-free space is created to house the electrical component, the actuator body (23). In the case of the manually actuated system shown in Figure 1(B), the seals (26, 27) prevent oil from leaking out of the shock absorber through the axial opening of the rod (3).

[0052] In addition, the piston pin (30) also comprises a first orifice (31) communicating with the expansion chamber (5), a second orifice (32) communicating with the adjusting body (12), a leakage orifice (33) rotating with respect to the first orifice (31), a second leakage orifice (34) having a larger cross section than the leakage orifice (33) for the piston pin (30) to pass through, and an axial orifice (36) for receiving the drive shaft (21) through which all the above orifices (31, 32, 33, 34) communicate. This figure also shows the configuration of the drive shaft (21) having a circular cross section. The drive shaft (21) comprises a first recess defining a first flow passage (16) and a second recess, preferably but not necessarily, located diametrically opposite and defining a second flow passage (17). The recess of the second flow passage (17) is preferably larger than that of the first flow passage (16) in order to reduce the pressure drop during the flow of the fluid.

[0053] The first flow passage (16) has a position and length such that it completely communicates with the inlet orifice (31) and the outlet second orifice (32) without reaching the free end of the drive shaft (21).

[0054] Next, the second flow passage (17) is preferably, but not necessarily, located radially opposite the first flow passage (16) and, like the first flow passage (16), completely connects the first orifice (31) and the second orifice (32), but the length of this second flow passage (17) is different in that it reaches the free end of the drive shaft (21).

[0055] On the other hand, it should be noted that with respect to the adjusting body (12), when the buffer is in the rest position, the floating piston (13) is not in contact with the primary valve (14).

[0056] The operation of the shock absorber of the present invention in the extension operation will be described below when it operates according to different control laws. In this situation, the fluid is divided, and part of it flows from the extension chamber (5) to the compression chamber (6) through the through conduit (28) through the piston (4) and the main fixed flow passage (42), or along the side passage through the primary valve (14) when it opens after a certain speed of the fluid, while the rest of the fluid passes through the central passage through the piston pin (30). The side passage through the piston (4) is formed in all damping control laws and is a normal passage in conventional shock absorbers, which may affect the flow rate when the flow passage is somewhat closed, while the central passage through the piston pin (30) will be described in detail below in the different damping control laws.

[0057] Figure 3B shows an alternative embodiment to that shown in Figure 3A. In this Figure 3B, a slide (47) is inserted between the flexible floating piston (13) and the primary valve (14). The slide (47) is movable along the same axis as the flexible floating piston (13) and is pushed by the flexible floating piston (13) to transmit a force to the primary valve (14) at a diameter defined by the step that forms the outermost periphery. The basic operation of the system is the same, and the slide (47) provides two advantages.

[0058] The first advantage is that the flexible floating piston (13) is well protected in its operation since it is completely enclosed in all directions by rigid walls, and therefore can be operated at higher pressures / forces without risk of failure due to lack of durability or ageing caused by application of continuous operating cycles.

[0059] The second advantage is that the diameter of the primary valve (14) to which the force generated in the flexible floating piston (13) is transferred can be selected. In this way, freedom is obtained to establish the level of coupling between the adjusting body (12) and the primary valve (14). Thus, it is possible to change the level of progressivity (roundness) of the damping force when the primary valve (14) is open in the hard control law, which is achieved by making the floating piston (13) flexible.

[0060] 4 shows a shock absorber operating according to a hard damping control law, in which it is intended to make the fluid flow between the expansion side chamber (5) and the compression side chamber (6) difficult in order to increase the load. In this case, the fluid circulates from the expansion side chamber (5) to the compression side chamber (6) through the conduit (28), the main fixed flow passage (42) and the first flow passage (16). The drive shaft (21) is rotated to a position such that the first flow passage (16) communicates with the first orifice (31), the second orifice (32) communicates with the second flow passage (17), and the leakage orifice (33) and the second leakage orifice (34) are blocked, as shown in cross sections EE and SS. On the one hand, by closing the leakage orifice (33) and the second leakage orifice (34), the leakage cross section is minimized and restricted to the fixed flow passages (42, 43) of the primary valve (14) and the secondary valve (15), respectively, creating a maximum level of damping for the low speed movement of the piston (4). Thus, the fluid enters through the first orifice (31), passes through the first flow passage (16), leaves through the second orifice (32) and circulates through the secondary fixed flow passage (43) located between the regulator body (12) and the secondary valve (15).

[0061] FIG. 4A shows an enlarged detailed view of the regulating body (12) having a floating piston (13) along with a primary valve (14) and a secondary valve (15).

[0062] On the other hand, the conduit (28) communicates with the pressure side chamber (6) through a primary valve (14) having a main fixed flow passage (42).

[0063] On the other hand, the first flow passage (16) is connected to the access passage (40) via the second orifice (32), which allows the fluid to enter the regulator chamber (41), and the fluid can leave the regulator chamber (41) towards the pressure side chamber (6) via the secondary valve (15) having a secondary fixed flow passage (43).

[0064] The fixed flow passages (42, 43) are always open, but they are in fact optional and may not even be present, regardless of whether the primary valve (14) or the secondary valve (15) is closed. In either of these cases, an increase in the pressure of the fluid opens the corresponding valve (14, 15), thus enlarging the flow cross section for the circulation of the fluid.

[0065] Thus, if a secondary fixed flow passage (43) is provided or if the pressure is sufficient to open the secondary valve (15), part of the fluid will go directly to the pressure side chamber (6), but part of this fluid will enter the regulator chamber (41) and act on the floating piston (13) to exert pressure on the primary valve (14) in an attempt to close it, which will cause the passage of fluid through the passage (28) of the piston (4) to be difficult, as the passage (28) will be closed in proportion to the force generated by this pressure. This Figure 4 reflects the movement of the floating piston (13) which moves the primary valve (14), which only occurs in the case of a hard control law, as described below.

[0066] In a preferred embodiment, the floating piston (13) is a deformable elastic element, for example made of rubber, having a toric configuration. Thus, at the moment when the floating piston (13) contacts the primary valve (14), a force is transmitted at the contact area, which is usually the central area of ​​the valve (14). However, when pressure increases, the floating piston (13) deforms, transmitting the force over a larger surface and tending to move towards the outer diameter of the valve (14). This is because the oil is free to exit between the secondary valve (15) and the regulator case (44) of the regulator (12), but not in the other space in contact with the floating piston (13), where the oil, being essentially incompressible, is trapped. This deformation can be seen in the detail of FIG. 4, resulting in a smooth and gradual transition between low and medium speed damping, as shown in the hard control law in FIG. 12.

[0067] Figure 5 shows a shock absorber operating according to the most commonly used average damping control law. In this case, as shown in cross sections EE and SS, the fluid circulates from the extension chamber (5) through the conduit (28), the leakage orifice (33) connecting with the second passage (17) of the drive shaft (21) and directly reaches the compression chamber (6). In this way, the leakage cross section of the hard control law is increased and the damping of the low speed movement of the piston (4) is reduced. The drive shaft (21) is rotated to a position in which the access of the fluid to the first orifice (31) is blocked, but the fluid can pass through the second leakage orifice (34) connecting with the first passage (16), which is not connected with the compression chamber (6) because the length of the first passage (16) does not reach the free end of the drive shaft (21). In this case, since the floating piston (13) does not move, the fluid circulates through the conduit (28) without any additional restriction, reducing damping for the hard control laws for medium and high speed operation of the piston (4).

[0068] FIG. 6 shows a shock absorber operating according to a soft damping control law, in which it is intended to facilitate the flow of fluid between the expansion side chamber (5) and the compression side chamber (6) in order to reduce the load. In this case, the fluid circulates from the expansion side chamber (5) to the compression side chamber (6) through the conduit (28) and the second flow passage (17). The drive shaft (21) is rotated to a position such that the second flow passage (17) connects to the first orifice (31) and the leakage orifice (33) and the second leakage orifice (34) are blocked, as shown in the cross section EE. Since the first orifice (31) has a larger flow passage cross section than the leakage orifice (33), it is larger than the leakage cross section in the intermediate control law, and as a result the damping force is reduced. In addition, the fluid continues to circulate through the conduit (28) without any additional restrictions.

[0069] Thus, the fluid enters the first orifice (31), circulates through the second flow passage (17) and leaves mainly through the opening at the end of the axial orifice (36) of the piston pin (30) until it reaches the pressure side chamber (6). A minimal oil flow is diverted through the second orifice (32) towards the regulator chamber (41). However, due to the very high resistance to the passage of the fluid through the second orifice (32), especially due to the access passage (40), this flow is negligible compared to the opening at the end of the axial orifice (36) and has no force to move the floating piston (13). This lack of effect is promoted by the presence of the floating piston (13) as an element that transmits the pressure of the regulator (12) to the primary valve (14). Without the floating piston (13), the pressure would be transmitted directly in the regulator (12) and even a minimal oil flow would be able to exert a certain closing pressure on the primary valve (14). In such a case, the soft control law produces a larger damping force from a constant piston (4) velocity than the medium control law.

[0070] 7 shows a shock absorber operating according to an ultra-soft damping control law. In this case, the drive shaft (21) is rotated to a position such that the fluid circulates from the expansion side chamber (5) through the conduit (28), via the second flow passage (17) through the second leakage orifice (34) and directly into the compression side chamber (6), as shown in cross sections EE and SS. In this situation, the fluid circulates through an orifice with a larger cross section than any of the previous cases, since the second leakage orifice (34) is the one with the largest flow section among all the orifices (31, 33, 34) communicating with the expansion side chamber (5), and therefore the resistance to the flow of the fluid in this embodiment is lower than in the previous embodiments, resulting in an ultra-soft damping control law.

[0071] As shown in FIG. 5, in this case the leakage orifice (33) connects with the first flow path (16) which has a closed end, so that fluid does not circulate in this manner.

[0072] 8-11 show the second embodiment according to FIGS. 4-7 respectively, where the shock absorber includes four modifications for hardening the control law.

[0073] The first modification consists in providing an additional regulating body (12') with a corresponding additional floating piston (13'), an additional secondary valve (15') and an additional second orifice (32'), so that the pressure side chamber (6) has two regulating bodies (12, 12') instead of one.

[0074] The second modification consists of omitting the second leakage orifice (34).

[0075] The third modification concerns the first orifice (31) and the second orifice (32) of the piston pin (30). Thus, a third leakage orifice (35) is provided, which is located as an extension of the existing first orifice (31), but has a substantially smaller flow cross section, and an additional second orifice (32') is provided, which is located corresponding to the additional adjusting body (12').

[0076] The first flow passage (16) and the second flow passage (17) both maintain their lengths, i.e. the first flow passage (16) has a length that connects the first orifice (31) with the second orifice (32), while the second flow passage (17) has a length that connects the first orifice (31) with the free end of the drive shaft (21). In addition, the drive shaft (21) comprises a third flow passage (18) that connects the first orifice (31) with the two second orifices (32, 32') but does not reach the free end of the drive shaft (21). In addition, it is preferably symmetrically located between the first flow passage (16) and the second flow passage (17) in the counterclockwise direction as viewed from the free end of the drive shaft (21).

[0077] Thus, FIG. 8 shows a shock absorber operating according to a super-hard control law. The fluid, via the conduit (28), passes through the primary valve (14) towards the compression chamber (6), enters through the first orifice (31), circulates through the third flow path (18) and leaves through the two second orifices (32, 32'). Here, the third leakage orifice (35) and the second flow path (17) are blocked. The leakage orifice (33) communicates with the first flow path (16), which is also blocked since it does not communicate with the second orifice (32) or with the opening at the end of the axial orifice (36). This situation is shown in the cross sections EE, S1-S1 and S2-S2. In this situation, part of the fluid enters the two adjusting bodies (12, 12') and acts on the corresponding floating pistons (13, 13'). The difference in this case is that the fluid leaving the additional, further away, second orifice (32'), in addition to going directly to the pressure side chamber (6) through the additional secondary valve (15'), also enters the chamber of the additional regulator (12') and presses the additional floating piston (13') to the secondary valve (15) of the regulator (12). This tends to block the flow of fluid from the upper second orifice (32) to the pressure side chamber (6), forcing the fluid to go to the regulator (12) and pushing the floating piston (13) of the regulator (12) to move the primary valve (14), which then tries to close to block the flow of fluid through the conduit (28) of the piston (4). This closing is proportional to the force generated by this pressure. However, the secondary valve (15) and the primary valve (14) are pushed by the floating pistons (13') and (13), respectively. This increases the resistance to oil flow through the secondary valve (15) compared to previously described designs. This increased resistance results in more pressure in the regulator chamber (41), which ultimately causes the floating piston (13) to exert more force against the primary valve (14).

[0078] 9 shows a shock absorber operating according to a hard damping control law. In this case, the drive shaft (21) is rotated to a position such that the fluid reaches the compression chamber (6) from the expansion chamber (5) through the conduit (28) and through two other paths. On the one hand, the fluid reaches through the third leakage orifice (35) and circulates through the second flow passage (17) which connects directly to the compression chamber (6) through an opening at the end of the axial orifice (36). On the other hand, the fluid also reaches through the first orifice (31) and circulates through the first flow passage (16) which connects to the second orifice (32), through the access passage (40) and the secondary valve (15) of the regulator (12), through the secondary fixed flow passage (43) if present or through an opening in the secondary valve (15) itself if a sufficient level of pressure is reached. In this situation, part of the fluid will go directly through the secondary valve (15) to the pressure side chamber (6), while the rest of the fluid will enter the regulator chamber (41) and act on the floating piston (13) to exert pressure on the primary valve (14) to close it, thereby making it difficult for the fluid to pass through the conduit (28) of the piston (4), where the conduit (28) will be closed in proportion to the force generated by this pressure. If there was no secondary fixed flow passage (43) or if the pressure was not high enough to open the secondary valve (15), all of the fluid would go to the regulator chamber (41) and act on the floating piston (13) to close the primary valve (14) with additional pressure.

[0079] Figure 10 shows a shock absorber operating according to the intermediate damping control law. In this case, the fluid reaches the compression chamber (6) from the extension chamber (5) via the conduit (28) and through the leakage orifice (33) which connects to the second passage (17) of the drive shaft (21) and directly to the compression chamber (6), as shown in the cross sections EE, S1-S1 and S2-S2. The drive shaft (21) is rotated to a position such that the fluid cannot access the first orifice (31), but the fluid can pass through the third leakage orifice (35) which connects to the first passage (16) which is not connected to the compression chamber (6) since the length of the first passage (16) does not reach the free end of the drive shaft (21). In this case, the floating piston (13) does not move, so the fluid circulates through the conduit (28) without any additional restrictions.

[0080] FIG. 11 shows a shock absorber operating according to a soft damping control law. In this case, the fluid circulates from the expansion chamber (5) to the compression chamber (6) through the second flow passage (17) via the conduit (28). The drive shaft (21) is rotated to a position such that the second flow passage (17) is connected to the first orifice (31) and the leakage orifice (33) and the third leakage orifice (35) remain blocked, as shown in the cross sections EE, S1-S1 and S2-S2, respectively, since these orifices are connected to the first flow passage (16) and the third flow passage (18), whose length does not reach the free end of the drive shaft (21). Since the first orifice (31) has a larger flow passage cross section than the leakage orifice (33), the pressure drop is smaller and therefore the damping force is greater than in the case shown in FIG. 10 for the intermediate control law. Additionally, for the same reasons as in the previous structures, fluid continues to circulate through the conduit (28) without any additional restriction.

[0081] Figure 12 shows a graph of the variation of the damping force as a function of the speed of the piston (4) for an extension movement according to the shock absorber shown in figure 1. The graph shows the graduality of the force application during the operation of the shock absorber according to the different control laws applied from hard to super soft, where the important advantage is that a floating piston (13) made of elastic material is provided, whose deformability provides a gradual transition between low-speed damping and medium-speed damping before the opening of the primary valve (14), avoiding abrupt opening of said primary valve (14), which would result in an abrupt change in gradient, as shown by the dashed line. This mechanism makes it possible to achieve a gradual increase in the damping force while at the same time eliminating irregularities in the terrain more effectively, minimizing the risk of chassis acceleration peaks and noise, and also improving comfort.

[0082] For low speed movements of the piston (4), the invention allows the selection of different levels of damping force by means of a fixed permanent leakage and a variable permanent leakage, which may or may not be included through a relief disk in the valve, and the variable permanent leakage is activated or deactivated according to a damping control law defined by the drive shaft (21) and the first orifice (31) and the leakage orifice (33) on the one hand, and the second orifice (32) and the axial orifice (36) on the other hand, as inlet and outlet orifices for the fluid from the piston pin (30) during the compression phase, respectively. The change of the fixed flow passages in the piston (4) also partially affects the damping force for low speed compression movements of the piston (4), as shown by the curves in FIG. 12.

[0083] For medium and high speed operation of the piston (4), the drive shaft (21) drives or de-drives the oil flow towards the adjusting body (12) to increase or decrease the level of damping force from the opening of the primary valve (14) with approximately equal gradient for all inclinations.

[0084] For a shock absorber that operates in both compression and extension, such as that shown in FIG. 2, the variation of damping force as a function of the velocity of the piston (4) is shown in FIG. 13, where the compression case is very similar to the extension case.

[0085] Figure 14A shows a new embodiment of the shock absorber of the present invention where a mechanical stop is provided for the rotational movement of the drive shaft (21). This modification affects the axial orifice (36) of the piston pin (30) and the drive shaft (21).

[0086] On the one hand, the free end of the drive shaft (21) has a longitudinal extension (24) which changes from a circular cross section to a semicircular cross section, reducing the cross section by half.

[0087] On the other hand, the axial orifice (36) is modified at the free end to change from a circular cross section to an end orifice (37) having a configuration defined by an orifice having an elongated, eccentric cross section.

[0088] The end orifice (37) has a length to accommodate at least a portion of the extension (24) of the drive shaft (21). In this way, the movement of the drive shaft (21) is limited to 90°, i.e., a quarter turn, because the walls of the end orifice (37) act as a mechanical stop to prevent further advancement of the extension (24). This is illustrated in cross section AA, which is shown at two different moments of rotation of the drive shaft (21), where the rotation of the drive shaft (21) is limited such that the shock absorber can only transition from the hard control law to the medium control law or vice versa, i.e., from the situation shown in FIG. 4 to the situation shown in FIG. 5.

[0089] This construction is advantageous because of its simplicity and because it allows the position of the orifice in the piston pin (30) relative to the flow passage in the drive shaft (21) to be controlled by the same part, the actuator (20), itself.

[0090] FIG. 14B shows another embodiment of the shock absorber of the present invention with an angle lock system consisting of a rotation limiting plate (45) at the base of the drive shaft (21), where the window limiting the rotation of the drive shaft (21) has a geometric shape of three-quarters of a circle. The drive shaft (21) is ground and has a flat surface at the end cross section, which has a suitable semicircular cross section that allows a 90° rotation in the window of the rotation limiting plate (45). This plate can be a separate element or can be integrated into the actual actuator body (23). In addition, a separation bush (46) is provided between the sealing gasket (26) and the rotation limiting plate (45). It can be seen that in this embodiment the drive shaft (21) is shown short because the second orifice (32) is moved upwards in the piston pin (30). The flat surface (48) of the piston pin (30) is extended until it reaches the access channel (40) of the adjustment body (12).

[0091] In any of the embodiments of the present invention, the flat surface (48) of the piston pin (30) serves to absorb axial dimensional variations caused by component tolerances, as well as axial dimensional variations caused primarily by the number and thickness of the piston (4) valves.

[0092] Figure 15 also shows an evolution of the mechanical stop shown in Figure 14. This evolution involves modifications made to both the axial orifice (36) of the piston pin (30) and the drive shaft (21), the difference being that instead of having a semicircular cross section, the extension (24) becomes a modified extension (25), which is now in the shape of a quarter of a circle, i.e., has two flat sides. In this configuration, the modified extension (25) of the drive shaft (21) does not act as a mechanical stop against the wall of the end orifice (37), but is allowed to continue rotating up to another quarter turn, at which point it actually acts as a mechanical stop again, limiting the rotational movement. This movement is shown in the diagram of Figure 15, where three bottom views show the position of the modified extension (25) relative to the end orifice (37).

[0093] Thus, control of the shock absorber position is achieved with three types of hard, medium and soft control laws.

[0094] To control the 90° rotation, i.e. the position according to the intermediate control law, a mechanism formed of a disk (39) and a spring (38) is introduced. The disk (39) is attached to the piston pin (30) by tabs and the spring (38) is compressed in place. The compression of the spring (38) creates a controlled contact force between the disk (39) and the piston pin (30), which in turn creates a controlled torque against rotation due to friction.

[0095] As the correction extension (25) rotates from 0° to 90°, it strikes the crescent shaped window in the disk (39), as shown in Figure 15. This contact introduces an additional calibrated load to the actuator (20), which appears as an increase in electrical consumption, which can be detected and its termination recorded.

[0096] As the shaft is rotated through 180°, the disk (39) is dragged along, its crescent-shaped window allowing free rotation of 90° until 180° is reached. Then, as it returns to the 90° position, the shaft moves freely and, once the desired position is reached, an increased load is again detected due to the shaft contacting the disk (39). Thus, three angular positions of the drive shaft (21) are controllable, two of which are controlled by fixed mechanical stops and the third by a rotary stop.

[0097] Finally, it should be noted that the present invention should not be limited by the embodiments described herein. Those skilled in the art can implement other configurations based on this specification. Therefore, the scope of the present invention is defined by the following claims.

[0098] The list of symbols used in the drawings is given below. [Explanation of symbols]

[0099] 1 Outer case 2 Inner tube 3. Rod 4 Piston 5 lateral chamber 6 Pressure chamber 7 Compensation Chamber 8 Oil level 9. Gas 10. Oil 11 Compression valve 12 Adjustment body 12' Additional adjustments 13 Floating Piston 13' additional floating piston 14 Primary Valve 15 Secondary Valve 15' Additional Secondary Valve 16 First Channel 17 Second Channel 18 The Third Stream 20 Actuator 21 Drive shaft 22 Actuator cable 23 Actuator body 24 Extensions for two positions 25 Extensions for 3 positions 26 First Seal 27 Second Seal 28 Conduit 30 Piston pin 31 First Orifice 32 Second Orifice 32' Additional secondary orifice 33 Leak orifice 34 Secondary leakage orifice 35 Third Leak Orifice 36 Axial Orifice 37 End Orifice 38 Spring 39 Discs 40 Access Channel 41 Adjustment chamber 42 Main fixed flow path 43 Secondary fixed flow path 44 Adjustment body case 45 Rotation limit plate 46 Separation Bush 47 Slides 48 Piston pin flat surface

Claims

1. 1. A shock absorber with multiple damping control laws, comprising a regulating body (12) having a primary valve (14) and a secondary valve (15) and a drive shaft (21) having a number of flow passages (16, 17), the drive shaft (21) being accommodated in an axial orifice (36) of a piston pin (30) having a number of orifices (31, 32, 33) intended to be aligned with the flow passages (16, 17) by the rotation of the drive shaft (21) and to determine the damping control law, and the second orifice (32) is in direct communication with the regulating body (12), the regulating body (12) comprising a floating piston (13) having an annular configuration and made of elastic material, which gradually transmits a force to the primary valve (14) depending on the pressure it receives.

2. The flow passages (16, 17) of the drive shaft (21) are a first flow passage (16) having a length communicating the first orifice (31) and the second orifice (32); and a second flow passage (17) having a length communicating between the first orifice (31) and the free end of the drive shaft (21); 2. The shock absorber having a plurality of damping control laws according to claim 1, characterized in that said shock absorber is configured as follows:

3. The orifices (31, 32, 33) of the piston pin (30) are a first orifice (31) communicating the expansion-side chamber (5) with the axial orifice (36) of the piston pin (30); a second orifice (32) that communicates the axial orifice (36) of the piston pin (30) and the compression side chamber (6) through the adjustment body (12); and A leakage orifice (33) communicating the expansion side chamber (5) with the axial orifice (36) of the piston pin (30).

2. The shock absorber having a plurality of damping control laws according to claim 1, characterized in that said shock absorber is configured as follows:

4. 2. The shock absorber with multiple damping control laws according to claim 1, characterized in that the piston pin (30) has a second leakage orifice (34) positioned as an extension of the leakage orifice (33) and having a larger flow cross section.

5. 2. The shock absorber having multiple damping control laws according to claim 1, further comprising a slide (47) positioned between the flexible floating piston (13) and the primary valve (14), the slide (47) being slidable along the piston pin (30), having a diameter that can be configured to have a function of transmitting a force received from the floating piston (13) to the primary valve (14), and having a function of protecting the floating piston (13).

6. 2. A shock absorber with multiple damping control laws as claimed in claim 1, characterized in that it comprises two adjusting bodies (12), one on each side of the piston (4), so that it can operate according to different damping control laws for extension and contraction.

7. 2. The shock absorber with multiple damping control laws according to claim 1, further comprising an actuator (20) housed in the rod (3) of the piston (4), driven by a cable (22) and attached to the drive shaft (21), whereby the selection of the damping control law is performed automatically.

8. 2. The shock absorber with multiple damping control laws according to claim 1, further comprising a stem attached as an extension to the drive shaft (21), whereby the selection of the damping control laws is performed by manual action.

9. 2. The shock absorber with multiple damping control laws according to claim 1, characterized in that the free end of the drive shaft (21) comprises a longitudinal extension (24) having a semicircular cross section and the axial orifice (36) comprises an end orifice (37) having an elongated cross section eccentric with respect to the drive shaft (21), whereby the movement of the drive shaft (21) is limited to a quarter turn as the walls of the end orifice (37) act as a mechanical stop together with the extension (24) of the drive shaft (21).

10. a rotation limiting plate (45) having a window with a geometric shape of three-quarters of a circle; the cross section of the end face of the drive shaft (21) for attachment to the actuator (20) has a semicircular cross section and passes through the window of the rotation limiting plate (45); 2. A shock absorber with multiple damping control laws according to claim 1, whereby the rotation of the drive shaft (21) is limited to a maximum of 90°.

11. said extension (24) being a modified extension (25) having a quarter circular cross section; a disk (39) fixed to the end of the piston pin (30), biased by a spring (38), and having a semicircular orifice through which the correction extension (25) passes; 2. The shock absorber with multiple damping control laws as claimed in claim 1, characterised in that the free movement of the drive shaft (21) is limited to a quarter turn and can be rotated a further quarter turn by dragging the disk (39) against the friction created by the pressure of the spring (38).

12. 2. The shock absorber with multiple damping control laws according to claim 1, further comprising an additional adjusting body (12') arranged in conjunction with the adjusting body (12), the adjusting body (12) being connected to the second orifice (32), and the additional adjusting body (12') being connected to an additional second orifice (32').

13. The shock absorber with multiple damping control laws according to claim 12, characterized in that the additional adjusting body (12') is arranged at a position further away from the expansion side chamber (5).

14. The shock absorber with multiple damping control laws according to claim 12, characterized in that the actuation shaft comprises a third passage (18) having a length communicating between the first orifice (31) and the two outlet orifices (32, 32').

15. The shock absorber having multiple damping control laws according to any one of claims 12 to 14, characterized in that the piston pin (30) is provided with a third leakage orifice (35) having a flow passage cross section smaller than the first orifice (31).

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