Motor vehicle comprising a hydraulic inertia damper with an inertia channel integrated into a cartridge, method and program based on such a vehicle
The twin-tube shock absorber system with a cartridge-integrated compensation channel and non-linear nozzle addresses integration issues of inertial dampers, offering a compact and efficient damping solution for vehicles.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- STELLANTIS AUTO SAS
- Filing Date
- 2025-12-12
- Publication Date
- 2026-07-23
AI Technical Summary
Existing inertial damper suspensions for vehicles are difficult to integrate into conventional suspension spaces due to their complex components and require additional channels, making them bulky and unsuitable for vehicle production, and they struggle to balance damping at low frequencies without compromising comfort at high frequencies.
A twin-tube shock absorber system with a compensation channel integrated into a cartridge, featuring a non-linear nozzle and hydropneumatic pressure accumulators, which is compact and adaptable to vehicle space, allowing for efficient damping without structural modifications.
The system provides a compact, space-saving solution that maintains performance by integrating a long compensation channel and non-linear nozzle in a cartridge, enhancing damping efficiency and adaptability to vehicle dynamics.
Smart Images
Figure FR2025000246_23072026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE OF THE INVENTION: MOTOR VEHICLE COMPRISING A HYDRAULIC INERTIA SHOCK ABSORBER WITH AN INERTIA CHANNEL INTEGRATED INTO A CARTRIDGE, METHOD AND PROGRAM BASED ON SUCH A VEHICLE
[0003]
[0001] The present invention claims priority from French application 2500408 filed on January 15, 2025, the content of which (text, drawings, and claims) is incorporated herein by reference. The invention relates to the field of land vehicle suspension, and more particularly to systems using the inertia of a fluid to generate forces that counteract the suspension movements of said vehicle.
[0004]
[0002] The suspension of land vehicles is achieved by combining spring and shock absorber functions necessary to guarantee both the comfort and the support of the vehicle, while protecting the mechanical components against strong vibrations.
[0005]
[0003] The role of the shock absorber function is to counteract the body movements transmitted via the wheels and axles from the road. This is generally achieved using viscous friction hydraulic devices comprising a cylinder in which a perforated piston moves, pushing viscous oil through these holes.
[0006]
[0004] However, to optimize the necessary compromise between comfort and body control, by improving comfort without degrading body control on the road, the shock absorber function can advantageously be achieved by using the inertia of a fluid passing through a channel, subjected to the (greatly amplified) accelerations produced by the movement of the piston.
[0007]
[0005] The principle of such a hydraulic inertia suspension is described in document FR2689951.
[0008]
[0006] Inertial damper suspensions, although they offer advantages in terms of comfort and body control, are not yet suitable for vehicle production. Indeed, they are difficult to integrate into the space generally allocated to a conventional suspension because they have more components; they require at least one channel (or pipe) of small diameter but several meters in length, through which a low-viscosity hydraulic fluid circulates.
[0009]
[0007] Furthermore, in order to achieve a damping effect at very low frequencies (to ensure body stability) without compromising comfort at high frequencies (leading to wheel bounce and vibrations), the solutions currently under consideration tend to complicate the system by adding bulky and uncommon components. These include, for example, additional channels and hydropneumatic pressure accumulators, among others, as described in document FR3096613. Documents FR3102098 and FR3100854, for instance, propose solutions for implementing such systems, but they remain difficult to implement.
[0010]
[0008] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution enabling the provision of a compact and space-saving system compared to the prior art.
[0011]
[0009] To achieve this objective, the invention proposes a motor vehicle comprising at least one axle equipped with a twin-tube shock absorber type suspension device, the suspension device comprising:
[0012] - a cylinder comprising an outer tube enclosing an inner tube, the inner tube enclosing a piston sliding within the inner tube, the piston being carried by the damper rod passing through the inner and outer tubes, the piston defining a first compensation chamber through which the damper rod passes and a second compensation chamber not through which the damper rod passes; and
[0013] - a clearing channel connecting the first clearing house to the second clearing house,
[0014] characterized in that said compensation channel is arranged in a cartridge fixed to the external tube.
[0015]
[0010] Advantageously, the invention provides a compact cartridge structure fixed to the cylinder, the cartridge housing the compensation channel. Furthermore, the cartridge protects the compensation channel from potential shocks or weathering.
[0011] Preferably, the cartridge is arranged and fixed at least partially around the portion of revolution of the outer tube.
[0016]
[0012] This allows the space around the shock absorber cylinder to be occupied, and saves space compared to prior art structures where the compensation channel is offset to the sides of the shock absorber.
[0017]
[0013] Preferably, the suspension device includes at least one nonlinear nozzle at the connection between the compensation channel and the second compensation chamber. This type of nozzle is also called a nonlinear nozzle or variable orifice.
[0018]
[0014] This allows for a cartridge structure enabling the installation of such a non-linear nozzle; and for configuring, by this non-linear nozzle, the behavior of the hydraulic fluid of the shock absorber.
[0019]
[0015] Preferably, said compensation channel comprises portions of tubing connected together by bends.
[0020]
[0016] This allows the structure of the compensation channel to be adapted to the physical properties corresponding to the vehicle carrying the suspension device.
[0021]
[0017] Preferably, the cartridge includes hydropneumatic pressure accumulators.
[0022]
[0018] This allows the physical properties of the hydraulic fluid to be adapted to the desired compensation for the vehicle carrying the suspension device.
[0023]
[0019] The invention further relates to a method for manufacturing a motor vehicle according to the invention, comprising the following steps:
[0024] - an evaluation stage in which the available space for the suspension device at the level of said axle is determined;
[0025] - a design stage in which a suspension device is designed and produced, including a cartridge corresponding to the determined space and said motor vehicle;
[0026] - a step of installing the cartridge at the level of said axle.
[0027]
[0020] Preferably, in the design stage, the number and size of the necessary pipes and elbows are determined.
[0028]
[0021] Preferably, in the design stage, the variation laws of the nonlinear nozzles are determined.
[0022] Another object of the invention relates to a computer program comprising program code instructions for the execution of the steps of the manufacturing process according to the invention, when said program is running on a computer.
[0029]
[0023] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, including:
[0030] - [Fig. 1] schematically illustrates an isometric view of the suspension device of a motor vehicle according to a preferred embodiment of the invention, with the cartridge fixed to the external tube;
[0031] - [Fig. 2] schematically illustrates a side view of the device in Figure 1; - [Fig. 3] schematically illustrates a top view (at the top) and a bottom view (at the bottom) of the device in the previous figures;
[0032] - [Fig. 4] schematically illustrates cross-sectional views along F-F and B-B of figure 3;
[0033] - [Fig. 5] schematically illustrates a side view of the isolated cartridge; - [Fig. 6] schematically illustrates cross-sectional views along AA, CC and EE of figure 5;
[0034] - [Fig. 7] schematically illustrates a cross-sectional view along DD of figure 5.
[0035]
[0024] The invention includes a simplification of the inertial suspension system compared to that described in document FR3096613, without degradation of performance.
[0036]
[0025] As the figures describe, the system consists of a cylinder comprising an inner tube 2 and an outer tube 1 of a twin-tube shock absorber. The outer tube 1 includes a compensation chamber with two compartments, a lower one 5 and an upper one 6, separated by a piston 4 fixed to the rod 3. These can be referred to as two compensation chambers 5, 6, here upper and lower, with reference to a vertical axis Z oriented upwards.
[0037]
[0026] The two compensation chambers 5, 6 are connected together by a long, thin channel 8. The piston 4 and the channel 8 each incorporate, at their lower ends, a non-linear nozzle 9 whose flow varies with pressure according to different predefined laws.
[0027] Thus, the inertial system architecture comprises the channel 8 with the associated nozzle 9 connected in series. The assembly is integrated into a cartridge 7 fixed to the outside of the outer tube 1 of the shock absorber. The complete channel 8 comprises sections of tubing 13, straight or curved, connected together by bends 12. The various sections of tubing 13, and the associated bends 12, form the complete channel 8, which is integrated into the cartridge 7.
[0038]
[0028] Each of the two lower ends 10 and upper ends 11 of the channel 8 are arranged on each side of the cartridge 7: at the bottom for the lower end 10 and at the top for the upper end 11.
[0039]
[0029] The non-linear nozzle 9 is fixed to the lower end 10, then this assembly is attached to the outer tube 1 of the shock absorber.
[0040]
[0030] The characteristics of the inertial channel 8 are obtained by adjusting the number and length of the tubes 13 in the cartridge 7, as well as the size of their cross-sections and the curvature of the bends 12.
[0041]
[0031] Regarding the implementation and advantages of the invention, the movement of the piston 4 in the inner tube 2 causes a transfer of fluid by means of the channel 8 which connects them together, from one compensation chamber (compartment 5 or 6) of the inner tube 2 to the other chamber (respectively compartment 6 or 5), depending on whether the suspension is in compression or expansion.
[0042]
[0032] The acceleration imparted to the fluid in the channel 8 is thus amplified by a factor (-) 2corresponding to the square of the ratio of the effective cross-section of piston 4 divided by the cross-section of channel 8.
[0043]
[0033] Thanks to the inertia effect, the reaction force, proportional to the acceleration of the mass of fluid contained in the channel 8, is greatly amplified.
[0044]
[0034] To maximize the desired inertial effect, the cross-sectional area of the channel 8 must therefore be small compared to that of the piston 4. However, the mass of the fluid, and consequently its volume at a constant fluid density, must also be as large as possible. This allows for a channel in the shape of a tube (long and thin), but limits pressure losses, which slows down the desired acceleration: a compromise must be made on the dimensions of the tubes 13 (pressure losses increase when the diameter of the tube 13 decreases and its length increases for a given inertia).
[0045]
[0035] Thus, for a low viscosity shock absorber oil type fluid (typically less than 20 cSt), calculations show that the tubes 13 which form the channel 8 typically have an internal diameter between 4 mm and 8 mm for a length between 2 m and 4 m.
[0046]
[0036] The invention allows this long channel 8 to be housed in a small volume in the form of a compact cartridge 7. The shape of this cartridge 7 can be easily adapted to be fixed to the body (outer tube 1) of the shock absorber so as to remain within the available space around it, taking into account the kinematics of the front or rear axles. The shape, position, and dimensions of the cartridge 7 can vary depending on the suspension configuration. The advantage offered by this design is that the inertial suspension can be installed in place of a conventional suspension without structural modification to the vehicle. Thus, the same vehicle model can be equipped with either a conventional or inertial suspension, depending on its version or the options chosen.
[0047]
[0037] The possible variants of the invention are as follows:
[0048]
[0038] The above example describes an inertial suspension architecture on a front shock absorber of a so-called pseudo McPherson axle, but it can be implemented on any type of front or rear axle or any other suspension architecture (double wishbone, multi-link, torsion axle, rigid axle, torsion beam,...).
[0049]
[0039] The cartridge may have different dimensions, may be taller or may make more than 90° around the shock absorber.
[0050]
[0040] The cartridge can be placed not necessarily vertically but also at certain angles of inclination and possibly horizontally.
[0051]
[0041] The internal tubes of the cartridge can vary in length, cross-section, and geometry / shape. The elbow connections of the tubes can have different radii of curvature.
[0042] The position and number of the adjustment nozzles can change depending on the suspension design, the archetype, and the dynamic settings of the vehicle.
[0052]
[0043] The cartridge can be fixed on the outer tube of the shock absorber but also on any other suspension or bodywork component.
[0053]
[0044] In the hydraulic circuit, there may also be an accumulation chamber.
[0054]
[0045] The flow rate of the non-linear nozzle can be adjusted in order to modify the pressure and frequencies to be treated.
[0055]
[0046] The invention further relates to a method and a manufacturing program for a suspension device as described above, and for a vehicle equipped with at least one such device.
[0056]
[0047] The program of the invention may be or include a manufacturing automation program and / or a program for calculating parameters and physical properties of the hydraulic fluid of the suspension device; and / or a program for designing the channel 8 and the cartridge 7.
Claims
DEMANDS 1. A motor vehicle comprising at least one axle equipped with a twin-tube shock absorber type suspension device, the suspension device comprising: - a cylinder comprising an outer tube (1) enclosing an inner tube (2), the inner tube (2) enclosing a piston (4) sliding within the inner tube (2), the piston (4) being carried by the damper rod (3) passing through the inner tube (2) and the outer tube (1), the piston (4) defining a first compensation chamber (6) through which the damper rod (3) passes and a second compensation chamber (5) not through which the damper rod (3) passes; and - a compensation channel (8) connecting the first compensation chamber (6) to the second compensation chamber (5), characterized in that said compensation channel (8) is arranged in a cartridge (7) fixed to the outer tube (1).
2. Motor vehicle according to claim 1, characterized in that the cartridge (7) is arranged and fixed at least partially around the part of revolution of the external tube (1).
3. Motor vehicle according to any one of claims 1 to 2, characterized in that the suspension device comprises at least one nonlinear nozzle (9) at the connection between the compensation channel (8) and the second compensation chamber (5).
4. Motor vehicle according to any one of claims 1 to 3, characterized in that said compensation channel (8) comprises portions of tubing (13) connected together by bends (12).
5. Motor vehicle according to any one of claims 1 to 4, characterized in that the cartridge comprises hydropneumatic pressure accumulators.
6. A method for manufacturing a motor vehicle according to any one of claims 1 to 5, comprising the following steps: - an evaluation step in which the available space for the suspension device at the level of said axle is determined; - a design stage in which a suspension device is designed and produced including a cartridge (7) corresponding to the determined space and said motor vehicle; - a step of placing the cartridge (7) at the level of said axle.
7. Manufacturing method according to claim 6, combined with claim 4, characterized in that in the design stage, the number and size of the tubes (13) and elbows (12) required are determined.
8. A manufacturing method according to any one of claims 6 to 7 combined with claim 5, characterized in that in the design stage, the variation laws of the non-linear nozzles are determined.
9. Computer program comprising program code instructions for carrying out the steps of the manufacturing process according to any one of claims 6 to 8, when said program is running on a computer.