Device for adjusting the posture of a motor vehicle and automobile shock absorber equipped with such device

Abstract

A device (9) for adjusting the attitude of a motor vehicle comprises a cylindrical body (10) including a first flange (12) adapted to form an upper seat for a main spring of a vehicle suspension, said cylindrical body (10) defining a chamber (14b) in which two linear actuators (24, 30) are slidable, a first actuator being connected to a damper (22) adapted to form a limit stop for the oscillations of the sprung mass of the vehicle, and a second actuator (30) being configured to be connected to the sprung mass of the vehicle.

Description

Technical Field

[0001] The present invention generally relates to the field of automobile parts; in particular, the present invention relates to an automobile shock absorber with a posture adjustment device. Summary of the Invention

[0002] Systems for adjusting the attitude of a motor vehicle are known which include actuators capable of varying the vertical travel of the vehicle's shock absorbers.

[0003] One object of the present invention is to provide a device which, on the one hand, allows adjusting the distance between a spring plate (connected to the unsprung mass, for example to a structure integral to the wheel hub, or to the cylindrical tube of a vehicle shock absorber) and the sprung mass of the vehicle (in order to vary the height of the sprung mass above the ground in static conditions); and, on the other hand, allows adjusting the distance between an elastic buffer and the unsprung mass of the vehicle in order to reduce or increase the vertical travel of the sprung mass relative to the unsprung mass (for example, by forming a limit stop for the cylindrical tube of the shock absorber during the compression phase of the shock absorber).

[0004] Another object of the present invention is to provide a device for adjusting the vehicle posture and for coordinated adjustment of the buffer clearance, which device has a simplified structure and small dimensions (especially in the radial direction).

[0005] To achieve this result, the attitude adjustment device for a motor vehicle according to the invention comprises a cylindrical body defining a chamber in which two actuators are slidably housed in the form of cylinders in which pistons slide, said cylinders being connected to a buffer adapted to form a limit stop in the compression of the sprung mass of the vehicle relative to the unsprung mass, and said pistons being connectable to the unsprung mass of the vehicle.

[0006] The actuator is configured to be driven to move axially by inputting pressurized fluid into a chamber housing the actuator.

[0007] After fixing a horizontal reference surface, the pressure of the fluid, passing through a radial flange that forms the upper mount of the main spring of the vehicle's suspension, simultaneously raises the first actuator (moving the buffer away from the shock absorber's unsprung mass or cylindrical tube, thereby increasing its compression stroke) and the second actuator (increasing the distance between the device's cylindrical body and the vehicle's sprung mass, thereby increasing the distance of the sprung mass from the ground) relative to the reference surface. This configuration achieves an optimal attitude under normal road conditions.

[0008] Conversely, by removing fluid from the chambers, both actuators are lowered relative to the reference plane, shortening the shock absorber's compression stroke and the sprung mass's ground clearance. This configuration optimizes the setup for higher performance conditions (e.g., using the vehicle on a racetrack).

[0009] Thus, with the adjustment device according to the invention, it is possible, by means of a single device having a compact layout, to adapt the configuration of the vehicle suspension to different road conditions, often giving priority to the vehicle's handling or driving comfort.

[0010] According to one aspect of the invention, the above and other objects and advantages are achieved by a device for adjusting the attitude of a motor vehicle and coordinated adjustment of the buffer clearance, and a vehicle shock absorber equipped with such a device, the device having the characteristics defined in the appended claims.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The functions and structural features of some preferred embodiments of the device for adjusting the posture of a motor vehicle to adjust the buffer clearance in a coordinated manner and the automobile shock absorber equipped with the device according to the present invention will now be described.

[0013] With reference to the accompanying drawings, in which:

[0014] - Figure 1 and Figure 2 is a longitudinal cross-sectional view of a device according to one embodiment of the present invention, suitable for adjusting the attitude of a motor vehicle and adjusting the buffer clearance in a coordinated manner, the device being shown in two operating configurations, a first attitude optimized for normal road use and a second attitude optimized for racetrack use;

[0015] - Figure 3 According to an embodiment of the present invention, Figure 1 A longitudinal section of the shock absorber showing the adjustment device in construction; and

[0016] - Figure 4 yes Figure 3 A longitudinal section of a shock absorber having Figure 2 Construct the device shown.

[0017] Detailed description

[0018] Before describing various embodiments of the invention in detail, it should be clarified that the invention is not limited in its application to the details of construction and configuration of components set forth in the following description or illustrated in the accompanying drawings.

[0019] The invention is capable of other embodiments and of being practiced or constructed in various ways. It is also to be understood that the phraseology and terminology are for the purpose of description and should not be construed as limiting.

[0020] For example, with reference to the figures, the device 9 for adjusting the attitude of a motor vehicle comprises a cylindrical body 10 including a radially projecting first flange 12 suitable for forming the upper bearing of a main spring of a vehicle suspension (for example a spring of a shock absorber).

[0021] The cylindrical body 10 defines a first axially lower chamber 14a and a second axially higher chamber 14b (relative to the orientation assumed by the device 9 in use conditions), is hermetically sealed above the second chamber 14b by a cover 16, and is configured to be fluidically connected to the outside of the cylindrical body 10 via a through hole 18 in the cylindrical body 10.

[0022] The first chamber 14a and the second chamber 14b are fluidically separated by a diaphragm 20 which is axially interposed between the first chamber 14a and the second chamber 14b.

[0023] There is also provided a bumper 22 slidably received in the first chamber 14a of the cylindrical body 10 and adapted to form a limit stop for vibration of the sprung mass of the vehicle when it approaches the unsprung mass of the vehicle.

[0024] The device 9 also includes a main actuator 24, which includes a main cylinder 26 that is slidably received in the second chamber 14b of the cylindrical body 10, and the main cylinder 26 can be axially moved from a first position (close to the diaphragm 20) to a second position (close to the cover 16) in response to the entry or discharge of fluid into the second chamber 14b.

[0025] The master cylinder 26 defines a third chamber 27 therein, which is fluidically connected to the second chamber 14b. The primary actuator 24 further includes a primary rod 28 extending axially through the diaphragm 20 and connected to the master cylinder 26 and the damper 22 at opposite ends thereof.

[0026] The main rod 28 is adapted to slide the damper 22 in the first chamber 14 a in the same direction as the sliding of the master cylinder 26 in the second chamber 14 b .

[0027] The device 9 also includes a secondary actuator 30 including an auxiliary piston 32 slidably received in the third chamber 27 of the master cylinder 26 , the auxiliary piston 32 being configured to move axially relative to the master cylinder 26 in response to fluid entering or being discharged from the third chamber 27 .

[0028] The secondary actuator 30 also comprises a secondary rod 34 axially passing through the cover 16 and connected at a first end to the auxiliary piston 32 , the other end of the secondary rod 34 being suitable for connection to a sprung mass of the vehicle.

[0029] Due to this construction, the entry of pressurized fluid into the second chamber 14b causes the master cylinder 26 to slide axially from a position near the diaphragm 20 to a position near the cover 16, while causing the damper 22 to retract toward the diaphragm 20 (thereby increasing the gap between the damper 22 and the unsprung mass of the vehicle when the device 9 is installed on the vehicle).

[0030] Simultaneously, the fluid entering the third chamber 27 causes the auxiliary piston 32 to slide within the master cylinder 26, moving the cylindrical body 10 away from the connection point of the secondary rod 34 and increasing the height of the vehicle's sprung mass off the ground.

[0031] According to a preferred embodiment, the cylindrical body 10 comprises a radially projecting shoulder 15 inside the second chamber 14 b. According to this embodiment, the side wall 26 a of the master cylinder 26 comprises a radially projecting portion adapted to abut against said shoulder 15 when the master cylinder 26 is in a position close to the diaphragm 20, thereby at least partially avoiding contact between said diaphragm and said master cylinder 26.

[0032] Advantageously, the cover 16 may have a first portion against which the master cylinder 26 abuts when the master cylinder is in its upper axial stroke position, and a second portion that protrudes axially further within the second chamber 14 b than the first portion, against which the auxiliary piston 32 abuts when the auxiliary piston is in its upper axial stroke position. In this way, the axial strokes of the master cylinder 26 and the auxiliary piston 32 can be geometrically decoupled, since the auxiliary piston 32 abuts the cover 16 before the master cylinder 26. According to an alternative embodiment (not shown), the cover 16 can also be configured in the opposite manner, i.e., so that the master cylinder 26 abuts the cover 16 before the auxiliary piston 32 (e.g., by providing a central portion of the cover 16, corresponding to a protruding portion of the auxiliary piston 32, to protrude outwardly from the cover 16).

[0033] According to a preferred embodiment, the master cylinder 26 comprises a base 26 b facing the diaphragm 20 and having at least one through hole 26 c therein adapted to fluidically connect the second chamber 14 b and the third chamber 27 .

[0034] Advantageously, the master cylinder 26 comprises a protrusion 26d projecting radially inside the third chamber 27, said protrusion 26d being suitable for forming a limit stop for the auxiliary piston 32 when said piston slides inside the master cylinder 26. In this configuration, the auxiliary piston 32 will thus be able to slide relative to the master cylinder 26 from a first position close to the base 26b of the master cylinder 26 to a second position close to the protrusion 26d (against which it can abut).

[0035] According to one embodiment (not shown), the device 9 is configured to form the upper support of the spring, interposed between the sprung and unsprung masses of the vehicle, in the absence of a damping device coaxial with the spring. In this case, the spring would be able to be placed under a structure integral with the wheel hub, and the device 9 would be connected to the frame associated with the sprung mass of the vehicle.

[0036] According to an alternative embodiment, Figure 2 and Figure 3As shown in the example in FIG, the device 9 is integrated into a conventional automobile shock absorber.

[0037] The shock absorber comprises a device 9 for adjusting the attitude of a motor vehicle according to any of the embodiments described above, said device 9 being connectable to the sprung mass of the motor vehicle via a secondary rod 34 .

[0038] The shock absorber further comprises a cylindrical tube 36 and a shock absorber rod 38. The cylindrical tube 36 is adapted to be connected to the unsprung mass of the motor vehicle. A shock absorber piston is slidable in the cylindrical tube 36 and is adapted to interact with the fluid contained in the cylindrical tube 36 to damp the vertical oscillatory motion of the sprung mass. The shock absorber rod 38 is slidably received by the cylindrical tube 36 and is movable integrally with the shock absorber piston. The shock absorber rod 38 has an end protruding from above the cylindrical tube 36, the end of which is integral with the bumper 22.

[0039] A spring 40 is also provided, one end of which engages the first flange 12 of the cylindrical body 10 and the other end of which engages a second flange 37 projecting radially from the cylindrical tube 36 and which is movable integrally with the cylindrical tube 36 .

[0040] In this configuration, it is possible, on the one hand, to adjust the overall length of the shock absorber (by operating the main actuator 30 and bringing the cylindrical body 10 closer to or further away from the restraint point of the secondary rod 34 by increasing or decreasing the vehicle's height above the ground), and, on the other hand, to adjust the distance of the buffer, that is, the distance between the buffer 22 and the cylindrical tube 36, in order to reduce or increase the maximum travel of this tube relative to the buffer during compression of the shock absorber. This last feature in particular allows the characteristics of the suspension to be made stiffer as desired, thereby reducing the maximum oscillations during the compression phase (in the case of the shock absorber, limiting the vertical excursions).

[0041] As a brief description of the working principle of the device, the following will specifically refer to Figure 3 and Figure 4 The embodiment shown describes an example of adjustment. However, the following can be easily applied with the necessary modifications even without providing a shock absorber coaxial with the main spring of the suspension, the spring being connected to an element rigidly attached to the wheel hub.

[0042] More specifically, Figure 3 The initial configuration of the device is shown, as shown in the initial setting, where priority is given to driving comfort. In said configuration, the two actuators 24, 30 are in their respective absolute upper end positions of travel (ie both rest against the cover 16).

[0043] In this way, the buffer 22 is retracted to the maximum extent towards the diaphragm 20, and the cylindrical body 10 is spaced apart from the connection point S of the device 9 to the sprung mass of the vehicle to the maximum extent. That is, fixed in the horizontal reference plane passing through the radial flange 12, the distance of the axial end of the buffer 22 (facing the unsprung mass) from the reference plane will be a1, the distance of the connection point S from the reference plane will be b1, and the total length of the shock absorber will be c1 (measured from the connection point S of the shock absorber to the sprung mass of the vehicle to the connection point U of the shock absorber to the unsprung mass).

[0044] On the other hand, Figure 4 A second configuration of the device is shown, shown in a second attitude, where vehicle handling and responsiveness are prioritized. In this configuration, the two actuators 24, 30 are in their respective absolute stroke lower end positions (i.e., the main cylinder 26 is in a position close to the diaphragm 20, and the auxiliary piston 32 is in a position close to the base 26b of the main cylinder 26).

[0045] In this way, the buffer 22 extends axially to the maximum extent relative to the diaphragm 20, and the cylindrical body 10 is maximally close to the connection point S of the device 9 to the sprung mass of the vehicle. That is, relative to the horizontal reference plane passing through the radial flange 12, the distance of the axial end of the buffer 22 (facing the unsprung mass) from the reference plane in this configuration will be a2 > a1, the distance of the connection point S to the sprung mass from the reference plane will be b2 < b1, and the total length of the shock absorber will be c2 < c1 (measured from the connection point S of the shock absorber to the sprung mass of the vehicle to the connection point U of the shock absorber to the unsprung mass).

[0046] Furthermore, in this specification and the claims, terms and expressions indicating position and orientation, such as "longitudinal", "lateral", "vertical" or "horizontal" refer to the longitudinal axis z of the cylindrical body 10.

[0047] Various aspects and embodiments of the device for adjusting the attitude of a motor vehicle and coordinating the adjustment of the buffer clearance according to the present invention have been described. It should be understood that each embodiment can be combined with any other embodiment.

[0048] In addition, the present invention is not limited to the described embodiments, but can vary within the scope defined by the appended claims.

Claims

1. A device (9) for adjusting the posture of a motor vehicle and coordinating the adjustment of the buffer gap, comprising: - a cylindrical body (10) comprising a radially projecting first flange (12), the first flange (12) being adapted to form an upper seat for a main spring of a vehicle suspension, the cylindrical body (10) defining an axially lower first chamber (14a) and an axially higher second chamber (14b), the second chamber (14b) being hermetically sealed above by a cover (16) and being configured to be fluidically connected to the exterior of the cylindrical body (10) via a through hole (18) in the cylindrical body (10), the first chamber (14a) and the second chamber (14b) being fluidically separated by a diaphragm (20), the diaphragm (20) being axially interposed between the first chamber (14a) and the second chamber (14b); - a buffer (22) slidably received in the first chamber (14a) of the cylindrical body (10) and adapted to form a limit stop for vibrations of the sprung mass of the vehicle when the sprung mass of the vehicle approaches the unsprung mass of the vehicle; and - A main actuator (24) comprising: - a master cylinder (26) slidably received in the second chamber (14b) of the cylindrical body (10), said master cylinder (26) being axially movable in response to fluid entering or being discharged from the second chamber (14b) and defining a third chamber (27) therein in fluid connection with the second chamber (14b); and - a main rod (28) axially extending through the diaphragm (20) and connected at its opposite ends to the master cylinder (26) and the damper (22), the main rod (28) being adapted to allow the damper (22) to slide in the first chamber (14a) in the same direction as the master cylinder (26) slides in the second chamber (14b); The device (9) further comprises a secondary actuator (30) comprising: - an auxiliary piston (32) slidably received in the third chamber (27) of the master cylinder (26), the auxiliary piston (32) being configured to move axially relative to the master cylinder (26) in response to fluid entering or being discharged from the third chamber (27); and - a secondary rod (34) which passes axially through the cover (16) and is connected at a first end to the auxiliary piston (32), the other end of the secondary rod (34) being suitable for connection to the sprung mass of the motor vehicle.

2. The device according to claim 1, characterized in that The cylindrical body (10) comprises a radially projecting shoulder (15) within the second chamber (14b), and wherein the side wall (26a) of the master cylinder (26) comprises a radially projecting portion adapted to abut against the shoulder (15) when the master cylinder (26) is in a position close to the diaphragm (20) to avoid contact between the diaphragm and the master cylinder (26).

3. The device according to claim 1 or 2, characterized in that The cover (16) has a first portion and a second portion. When the main cylinder (26) is at an upper end position of an axial stroke, the main cylinder (26) abuts against the first portion. The second portion protrudes axially further in the second chamber (14b) relative to the first portion. When the auxiliary piston (32) is at an upper end position of an axial stroke, the auxiliary piston (32) abuts against the second portion.

4. The device according to claim 1 or 2, characterized in that The master cylinder (26) includes a base (26b) facing the diaphragm (20) and having at least one through hole (26c) therein adapted to connect the second chamber (14b) and the third chamber (27) in a fluid connection.

5. The device according to claim 3, characterized in that The master cylinder (26) includes a base (26b) facing the diaphragm (20) and having at least one through hole (26c) therein adapted to connect the second chamber (14b) and the third chamber (27) in a fluid connection.

6. The device according to claim 1 or 2, characterized in that The master cylinder (26) comprises a protrusion (26d) radially protruding in the third chamber (27), wherein the protrusion (26d) is adapted to form a limit stop for the auxiliary piston (32) when the auxiliary piston (32) slides in the master cylinder (26).

7. The device according to claim 3, characterized in that The master cylinder (26) comprises a protrusion (26d) radially protruding in the third chamber (27), wherein the protrusion (26d) is adapted to form a limit stop for the auxiliary piston (32) when the auxiliary piston (32) slides in the master cylinder (26).

8. An automobile shock absorber, comprising: - a device (9) for adjusting the attitude of a motor vehicle and for coordinated adjustment of the buffer play according to any of the preceding claims, which can be connected to the sprung mass of the motor vehicle via a secondary lever (34); - a cylindrical tube (36) suitable for being connected to an unsprung mass of a motor vehicle, a shock absorber piston being slidable in said cylindrical tube (36) and being suitable for interacting with a fluid contained in said cylindrical tube (36) in order to damp the vertical vibratory movement of said sprung mass, said buffer (22) being suitable for forming an upper abutment for the vertical stroke of the cylindrical tube during the compression phase of the automobile shock absorber; - a shock absorber rod (38) slidably received by the cylindrical tube (36) and movable integrally with the shock absorber piston, the shock absorber rod (38) having an end projecting above the cylindrical tube (36), the end being integral with the buffer (22); and - a spring (40) having one end engaged with the first flange (12) of the cylindrical body (10) and the other end engaged with a second flange (37) projecting radially from the cylindrical tube (36), the second flange (37) being movable integrally with the cylindrical tube (36).

Images