NL2007727C2

NL2007727C2 - Suspension assembly, telescopic fork and vehicle comprising the same.

Info

Publication number: NL2007727C2
Application number: NL2007727A
Authority: NL
Inventors: Eric Alexander Lindeman; Theodorus Arnoldus Gerardus Theunissen
Original assignee: Tractive Suspension B V
Priority date: 2011-11-06
Filing date: 2011-11-06
Publication date: 2013-05-08
Also published as: WO2013066158A1

Abstract

The present invention relates to a suspension assembly, a telescopic fork and vehicle comprising the same. According to the invention, a cover is used in which an electrical coil is arranged. During operation, the inductance of this coil is measured. Due to Eddy currents in the inner or outer tube of the suspension assembly, the effective inductance of the electrical coil can be used to determine the relative position between these tubes.

Description

Suspension assembly, telescopic fork and vehicle comprising the same

The present invention relates to a suspension assembly, 5 a telescopic fork and vehicle comprising the same.

Within the context of the present invention, a suspension assembly is an assembly for at least partly forming a suspensions system for a vehicle, and in particular for motorcycles. A damper is an example of a 10 suspension assembly that can be used for forming a suspension system.

The present invention is related to suspension assemblies that comprise an inner tube and an outer tube, wherein the inner tube and the outer tube are configured to 15 move telescopically with respect to each other. This telescopic movement is subjected to a spring force that urges the inner tube and the outer tube to move away from each other along an axial direction of the inner tube and the outer tube. It should be noted that within the context 20 of the present invention, tubes should not be interpreted too strictly as only comprising hollow cylindrical tubes. Other elongated forms, such as bars or rods, are also regarded as tubes.

Such a suspension assembly is known from US 5,218,308 25 in the form of a damper. The known damper comprises a magnetisable cylinder in which a piston with piston rod is moveably mounted. A protective cover is employed that coaxially overlaps the cylinder at least partly and which is fixedly connected to the piston rod. This cover protects a 30 part of the piston rod that extends outside of the cylinder against dust or other contaminants. In addition, an electrical coil is arranged in the protective cover which is electrically isolated from the cylinder and which is 2 configured to generate a magnetic field that extends through the cylinder.

An electrical parameter, such as the inductance of the electrical coil, changes due to the amount of magnetisable 5 material within the electrical coil. More in particular, the inductance will increase with increasing overlap between the protective cover and the cylinder. This inductance can be measured by connecting an alternating current (AC) source to a series connection of the electrical coil and a resistor, 10 and to subsequently use a detector for detecting the voltage over the electrical coil.

A drawback of the known damper is that it relies on the cylinder being made from magnetisable material. Already existing dampers cannot be modified to include the 15 abovementioned functionality.

An object of the present invention is to provide a suspension assembly which allows a determination of the relative position of the inner tube and outer tube.

A further object is to provide a suspension assembly 20 that can use existing dampers or existing suspension assemblies to at least a large extent.

Another object of the present invention is to provide a suspension assembly which allows the absolute position of the inner tube and/or outer tube and/or a direction of the 25 telescopic movement.

According to a first aspect of the present invention, at least one of these objects is achieved with the suspension assembly of claim 1. This suspension assembly comprises an inner tube and an outer tube, wherein the inner 30 tube and the outer tube are configured to move telescopically with respect to each other. The telescopic movement is subjected to a spring force that urges the inner tube and the outer tube to move away from each other along 3 an axial direction of the inner tube and the outer tube. The suspension assembly further comprises an electrically insulating cover that is stationary arranged with respect to one of the inner tube and outer tube and which is arranged 5 to coaxially overlap the other tube of the inner tube and outer tube during at least part of the telescopic movement between the outer tube and the inner tube. It should be noted that the other tube is electrically conducting.

The suspension assembly also comprises an electrical 10 coil arranged in or at the cover, wherein the electrical coil is electrically isolated from the other tube and is configured to generate a magnetic field that extends through the other tube. In addition to that, the assembly comprises an alternating current (AC) source that in an assembled 15 state of the assembly is coupled to the electrical coil to form an electrical circuit. The assembly of the present invention further includes a detector for detecting a value of an electrical parameter of the electrical circuit, such as the current through or the voltage over the electrical 20 coil.

According to the present invention, the suspension assembly further comprises a processing unit for determining the relative position of the inner tube and the outer tube using a change in the value of the electrical parameter with 25 respect to a known value of the electrical parameter at a predefined relative position of the inner tube and the outer tube. This change is caused by Eddy currents generated in the other tube by the magnetic field from the electrical coil.

30 Hence, according to the invention, the relative position between the inner and outer tube can be determined using the Eddy current effect. This also illustrates why it is important to have the cover made from electrically 4 insulating material, otherwise the cover itself would shield the electrical coil thereby preventing it from generating a magnetic field inside the other tube. The latter aspect can be regarded as a definition of electrically insulating, 5 meaning that the conductivity of the cover should not be so high as to prevent the determination of the relative position between the inner and outer tube based on the Eddy current effect.

In contrary to the known damper, the suspension 10 assembly of the present invention does not rely on the magnetic properties of a cylinder or tube to operate.

Instead the operation of the assembly is based on the generation of Eddy currents under the influence of the magnetic field that is generated by the electrical coil.

15 These Eddy currents partly cancel the incoming magnetic field via induction.

As most existing damper systems today have electrically conductive cylinders, the present invention can easily be applied to these damper systems without incurring excessive 20 costs. In most systems, the cover, if present, needs to be replaced by a cover with an electrical coil arranged therein .

In an embodiment, the cover is fixedly connected to or integrally connected and/or integrally formed with the one 25 of the inner tube and outer tube. By having the cover move along with one of the tubes, a correlation between the overlap of the cover and the other tube and the position of said one tube can be established.

In an embodiment, material of the other tube is chosen 30 such that a measured reactance of the electrical coil decreases with increasing overlap between the other tube and cover at an operating frequency of said AC source.

5

It should be noted that these considerations should apply at the operating frequency and possibly also the amplitude of the AC source.

In a further embodiment, the cylinder comprises 5 magnetisable material, and an operating frequency and preferably an amplitude of the AC source is chosen such that, at that frequency and amplitude, the decreasing effect on the measured inductance caused by the Eddy currents dominates the increasing effect on the measured inductance 10 caused by magnetisation of the cylinder. Suitable materials for which the Eddy current effect dominates are Aluminium, Magnesium and various types of stainless steel (310/316).

In an embodiment, the assembly comprises a memory holding a correlation between the relative position of the 15 inner tube and the outer tube and a corresponding value of the electrical parameter. In this case, the processing unit can be configured to extract the relative position between the inner tube and the outer tube from the memory using the detected value of the electrical parameter.

20 The correlation can be established in a calibration routine. During such routine, the inner and outer tubes are put at various known and/or measured positions, and the resulting electrical parameter is measured and stored in the memory.

25 In an embodiment, the detector is a peak detector configured to measure the peak voltage over and/or the peak current through the electrical coil. Typically, such detector comprises a diode connected to parallel resistor capacitor circuit. Such circuit enables the charging of the 30 capacitor if the voltage over the diode is larger than the instantaneous measured voltage minus the forward voltage of the diode. When this condition is not met, the capacitor will gradually discharge through the resistor. By choosing 6 an appropriate time constant for the parallel connection of resistor and inductor, it can be ensured that the peak voltages are appropriately followed by the peak detector both in an increasing and decreasing direction.

5 In an embodiment, the electrical circuit comprises a resonance circuit that incorporates the electrical coil. By operating the electrical circuit such that it operates at or close to a resonance freguency of the electrical circuit, at a predefined relative position of the inner and outer tube, 10 a high sensitivity can be obtained. If needed, resistive components could be added in case the range between maximum and minimum values becomes too excessive.

When using a resonance circuit, small variations in the position between inner and outer tube result in a change in 15 inductance of the electrical coil in particular when the inductance value moves away from the value at which the resonance circuit resonates at the operating freguency.

The predefined relative position can correspond to a default position when mounted on a motorcycle. For instance, 20 the default position could correspond to the relative position of the inner and outer tube when the motorcycle has been parked or the ride height of the motorcycle. Another possible position could be the position in which the suspension assembly is fully extended. In a further 25 embodiment, the resonance circuit can be tuned externally for changing the resonance frequency to thereby correct a change in default position. For instance, a variable capacitor or inductor could be included in the electrical circuit. Another option would be to change the resonance 30 frequency of the source. In addition, the amplitude of the AC source could be changed to tune the dynamic range with respect to following processing logic and/or circuitry.

7

In an embodiment, the resonance circuit comprises a capacitor for forming a series resonance LC network with the electrical coil.

In an embodiment, the one of the inner tube and outer 5 tube is the inner tube and the other tube is the outer tube. Hence, in this embodiment, the cover moves along with the inner tube and/or keeps a fixed positional relationship therewith.

In a further embodiment, the outer tube comprises a 10 cylinder and the inner tube comprises a piston with piston rod moveable in the cylinder. In this embodiment, the cover is a protective cover for protecting a part of the piston rod that extends outside of the cylinder. The cylinder may comprise hydraulic fluid to dampen the telescopic movement 15 between the cylinder and piston rod. Furthermore, the assembly may comprise a coil spring arranged between a support element that is fixedly connected to the inner tube and a support element that is fixedly connected to the outer tube. As such, this embodiment represents a damper with an 20 integrated position sensor for measuring the relative position between the piston and the cylinder.

The invention also provides a telescopic fork for a vehicle, such as a motorcycle, that comprises the abovementioned suspension assembly. In this fork, the inner 25 tube and the cover are fixedly connectable to a connecting element, such as a motorcycle yoke, that connects the inner tube to a frame of the vehicle. The outer tube is connectable to a wheel axis. Hence, both the cover and the inner tube can be connected to the connection element.

30 Alternatively, the cover can be connected to the connection element via the inner tube.

During operation, and when the telescopic fork compresses, e.g. when the vehicle encounters an obstacle, 8 the inner tube and outer tube will perform a telescopic movement towards each other. Because the diameter of the cover is larger than that of the outer tube, they will overlap (further). As a result, Eddy currents will be 5 induced, allowing the determination of the relative position of the inner and outer tube.

In another embodiment of the suspension assembly, the one of the inner tube and outer tube is the outer tube and the other tube is the inner tube. Hence, in this embodiment, 10 the cover moves along with the outer tube and/or keeps a fixed positional relationship therewith.

The invention also provides a further embodiment of a telescopic fork for a vehicle. This fork comprises a pair of parallel and spaced-apart fork tube assemblies, wherein each 15 fork tube assembly comprises a second inner tube and a second outer tube that are configured to move telescopically with respect to each other. Each fork tube assembly further comprises a coil spring arranged inside the fork tube assembly between a support element of the second inner tube 20 and a support element of the second outer tube. Here, at least one fork tube assembly comprises the suspension assembly in which the cover moves along with the outer tube and/or keeps a fixed positional relationship therewith. The outer tube of the assembly is fixedly connected to the 25 second inner tube on an inside thereof, and the inner tube is fixedly connected to the second outer tube on an inside thereof.

In a further embodiment of the telescopic fork, the inner tube comprises an electrically conductive piston rod 30 that is connected to a piston. The outer tube comprises a cylinder in which the piston is moveably mounted. In addition, the piston rod is fixedly connected to the second 9 outer tube and the cylinder is fixedly connected to the second inner tube.

Hence, when the telescopic fork compresses, and the second inner and outer tube move towards each other, the 5 piston rod will move through the cylinder. By having the outer tube made of electrically insulating material, Eddy currents can be generated in the piston rod by the electrical coil in the cover, allowing the determination of the relative position between the piston rod and the 10 cylinder and thereby the relative position between the second inner tube and the second outer tube.

In a further embodiment, the cylinder is integrally connected or fixedly connected with the cover. It is therefore possible to have the cover acting as the cylinder. 15 By at least partially filling the cylinder with a hydraulic fluid, damping can be achieved for the telescopic movement between the second inner tube and the second outer tube. In this respect, the electrical conductivity of the hydraulic fluid should be kept as low as possible.

20 The invention also provides a vehicle, in particular a motorcycle, that comprises any of the embodiments of the suspension assembly and/or the telescopic fork as discussed above.

Next, the invention will be described in more detail 25 under reference to the accompanying drawings, wherein:

Figure 1 illustrates a schematic cross-sectional view of a damper according to the present invention;

Figure 2 illustrates a partly opened view of a damper corresponding to the schematic damper of figure 1; 30 Figure 3 depicts a detailed view of the protective cover of figure 2;

Figure 4 illustrates an electrical circuit for use together with the damper of figure 1; 10

Figure 5 shows a system diagram of a damper assembly in accordance with the invention;

Figure 6 shows an application of the general inventive concept of the present invention in a known suspension 5 system; and

Figure 7 shows an application of the general inventive concept of the present invention in a telescopic adjustable fork.

In figure 1, a schematic cross-sectional view is 10 depicted of a damper according to the present invention. The same components are depicted in partially cut open views in figures 2 and 3. The damper comprises a cylinder 1 which is divided into a hydraulic fluid filled part 2 and a gas filled part 2' by a floating piston 3. The hydraulic fluid 15 filled part 2 can for instance be filled with oil, whereas nitrogen can be used to fill part 2' .

A piston 4 connected to piston rod 5 is moveably mounted in cylinder 1. At one end, cylinder 1 is closed by a cap 6 which comprises a hole through which piston rod 5 can 20 translate. This connection is sealed to prevent hydraulic fluid from leaking out of cylinder 1.

At one end of piston rod 5 a support plate 7 is mounted. A similar plate 7' is mounted at the opposing side of the damper. Plates 7, 7' support a coil spring 8 25 therebetween. Furthermore, on both sides of the damper, connectors 9, 9' are provided to connect the damper to other parts, such as parts of the suspension system.

Piston rod 5 is protected against dirt or other contaminants by a protective cover 10. Inside cover 10, 30 which is depicted in figure 1 as a hollow jacket, an electrical coil 11 is arranged that is electrically isolated from the walls of cover 10. Protective cover 10 has a fixed position and moves along with piston rod 5.

11

Piston rod 5, protective cover 10, and support plate 7 move as a single unit towards and away from cylinder 1. As such, the relative position between cylinder 1 and piston rod 5 can be changed.

5 During inward and outward motion of piston 4, a damping effect is achieved by a valve mounted on piston 4. This valve allows hydraulic fluid to pass between the chambers behind and in front of piston 4. The flow resistance offered by this valve largely determines the damping characteristics 10 of the damper.

Coil spring 8 is pre-loaded such that it urges protective cover 10 to move away from cylinder 1. Coil spring 8 is responsible for absorbing shocks related to positive travel of the suspension system in which the damper 15 may be used. Here, it is noted that positive travel corresponds to the situation where a net force is exerted on connectors 9, 9' causing the protective cover 10 to move towards cylinder 1. This for instance occurs when a motorcycle encounters an object on the road. In such case, 20 the damper will first retract (positive travel) against the spring bias of coil 8, and will then extend (negative travel) as a result of the spring bias of coil 8.

When piston rod 4 moves inwards, the total available volume in chamber 2 for the hydraulic fluid decreases as a 25 result of the volume of piston rod 4. To prevent excessive pressure build-up, floating piston 3 will move towards support plate 7' . On the other hand, a resilient element in the form of a rebound rubber 12 is placed inside cylinder 2 fixedly connected to cap 6. It counteracts coil spring 8 30 when it comes into contact with piston 4. Consequently, when the wheel of a motorcycle to which the damper assembly is connected is lifted in air, an equilibrium position will be reached in which the unsuspended weight and any pre-loading 12 of coil spring 8 is compensated by the compression of rebound rubber 12. Moreover, rebound rubber 12 prevents hard contact between cap 6 and piston 4.

Cylinder 1 is made from conductive material, such as 5 Aluminium. Because electrical coil 11 is wound like a solenoid, a magnetic field can be applied inside cylinder 1. As a result, an electric field will be induced in cylinder 1 causing Eddy currents to flow that will counteract the applied magnetic field. As Eddy currents are generated via 10 induction, they will only play a part in time-varying magnetic fields. Protective cover 10 should be made of nonconducting or poorly conducting material, such as plastics, to allow magnetic fields to penetrate cylinder 1.

As can be seen in figure 1, protective cover 10 will 15 increase its overlap with cylinder 1 under positive travel. As a result, the effective inductance of electrical coil 11 will be a decreasing function of the positive travel.

Figure 4 illustrates an electrical circuit which can be used in combination with the damper assembly of figure 1. In 20 figure 1, electrical coil 11 is represented by inductance LI and resistance RL. The latter is not only related to the Ohmic losses in the electrical wires of coil 11 but also to the dissipation by the Eddy currents in cylinder 1.

An alternating voltage source VAC is used to drive the 25 circuit. A capacitor Cl is used to form a LC resonant circuit together with LI. The voltage over LI is detected using a conventional peak detector comprising a diode D1 and a parallel connection of a capacitor C2 and resistor R1. The voltage over this parallel connection V0ut corresponds, if 30 the time constant is chosen appropriately, to the peak value of the time-varying voltage difference over LI.

By changing the relative position between piston rod 4 and cylinder 1, the inductance LI of electrical coil 11 13 changes. For a large overlap between cylinder 1 and electrical coil 11, the inductance will be smaller than for a small overlap.

Figure 5 shows a general schematic of a further part of 5 the signal processing required to output the relative position between cylinder 1 and piston rod 4.

The signal outputted by detector 20 is fed to a signal processing unit 21. Here, detector 20 comprises elements Dl, Rl, and C2 of figure 4.

10 Central processing unit 21 will consult a memory 22 that contains the results of a previously established calibration. This calibration comprises a relation between the relative position x between cylinder 1 and piston rod 4 (see figure 1) and the corresponding output voltage V0ut of 15 detector 20. Such calibration can for instance be carried out in the factory.

After consulting memory 22, signal processing unit 21 outputs the current relative position 23. This information can for instance be used in other control systems of the 20 motorcycle that monitor for instance the center of gravity, or that control the amount of damping in the system.

Figure 6 shows an application of the general inventive concept of the present invention in a known suspension system. In this figure, a part of a conventional telescopic 25 fork is depicted. It comprises an inner tube 24 and an outer tube 25 that can move telescopically with respect to each other, although subjected to a pre-tensioned coil spring (not illustrated). Inner tube 24 is on one end connected to a connecting element, which connects inner tube 24 to a 30 frame of a vehicle, in this case being a motorcycle. To that end, the connecting element can be in the form of a yoke. At end 26, inner tube 24 is connected to this yoke. The same holds for position 27, where cover 28 is connected to a 14 bottom part of the yoke. The yoke shields the part of inner tube 24 between end 26 and position 27. At end 29 of outer tube 25, a wheel axle can be mounted.

In this embodiment, cover 28 has a fixed positional 5 relationship with inner tube 24. When the motorcycle encounters an obstacle, outer tube 25 will move towards the yoke, thereby increasing the overlap between outer tube 25 and cover 28. Because outer tube 25 is electrically conductive, Eddy currents will be generated allowing a 10 determination of the relative position between inner tube 24 and outer tube 25 in accordance with the inventive concept of the present invention.

Figure 7 shows an application of the general inventive concept of the present invention in a telescopic fork of the 15 known upside-down type.

This fork comprises an outer tube 30 and an inner tube 31 that can move telescopically with respect to each other although subject to the spring force caused by pre-tensioned coil spring 32 that rests against support elements 33, 34.

20 Inside inner tube 30, a piston rod 35 is fixedly connected. Piston rod 35 is connected to a piston 36 that is moveably mounted in a cylinder 37.

Piston rod 35 is electrically conductive. Moreover, cylinder 37 and the cover of the present invention are 25 integrally formed, i.e. the cover forms cylinder 37.

Consequently, the electrical coil inside cylinder 37 will generate Eddy currents in piston rod 35. If outer tube 30 and inner tube 31 move towards each other, piston rod 35 will extend more inside cylinder 37. Hence, the overlap 30 between piston 35 and cylinder 37 increases, resulting in a lower effective inductance of the electrical coil inside cylinder 37. By measuring the inductance and comparing it with a previously established calibration, the relative 15 position of outer tube 30 and inner tube 31 can be determined.

It may be advantageous to at least partially fill cylinder 37 with non-conductive hydraulic fluid. This will 5 dampen the telescopic movement of outer tube 30 and inner tube 31. To that end, piston 36 may be equipped with a valve that allows fluid communication between the different chambers it divides cylinder 37 into.

In the embodiments described above, a relative position 10 was determined between an inner and outer tube. However, as mostly one of those tubes has a fixed position, e.g. via a connection to a frame of a vehicle, the present invention therefore also provides for determining the absolute positions of both the inner and outer tube.

15 Moreover, by taking a derivative of the position versus time, a speed can be calculated as well as a direction of movement. This information can be fed back to a control system of the vehicle to adjust the suspension settings according to the preference of a user and/or to the road 20 conditions.

It will be apparent to a skilled person that the present invention is not limited to the embodiments which have been described but that various modifications can be implemented without deviating from the scope of the 25 invention, which is defined by the appended claims.

Claims

A suspension composition, comprising: an inner tube; 5 an outer tube, wherein said inner tube and said outer tube are arranged to move telescopically relative to each other, said telescopic movement being subjected to a spring force which causes the inner tube and the outer tube to move away from each other along an axial direction of the inner tube and the outer tube; an electrically insulating cover which is arranged stationarily with respect to one of the inner tube and outer tube and which is arranged to coaxially overlap the other tube of the inner tube and outer tube during at least a part of the telescopic movement between the outer tube and the inner tube, wherein said other tube is electrically conductive; an electric coil disposed in or on said cover, wherein the electric coil is electrically insulated from the other tube and adapted to generate a magnetic field extending through the other tube; an alternating current (AC) source coupled to the electric chair in an assembled state of the assembly to form an electric circuit; a detector for detecting a value of an electrical parameter of the electrical circuit, such as the current through or the voltage across said electrical coil; characterized in that the suspension composition further comprises a processing unit for determining the relative position of the inner tube and the outer tube using a change in the value of the electrical parameter with respect to a known value of the electrical parameter at a predetermined relative The position of the inner tube and the outer tube, the said change being caused by Eddy currents generated in the other tube by the magnetic field of the electric coil.

The suspension assembly of claim 1, wherein the cover is rigidly connected to or integrally connected to and / or integrally formed with said one of the inner tube and outer tube.

3. Suspension composition according to claim 1 or 2, wherein material from the other tube is selected such that a measured reactance of the electric coil decreases with increasing overlap between the other tube and coverage at an operating frequency of said AC source.

4. Suspension assembly according to claim 3, wherein the other tube comprises magnetizable material, and wherein the operating frequency and preferably an amplitude of the AC source is chosen such that at that frequency and amplitude the decreasing effect on the measured inductance caused by the Eddy currents the increasing effect on the measured inductance caused by magnetization of the other tube dominates.

5. Suspension assembly according to any of the preceding claims, further comprising a memory for holding a correlation between the relative position of the inner tube and outer tube and a corresponding value of the electrical parameter, the processing unit being adapted to extract the relative position between the outer tube and the inner tube from the memory using the detected value of the electrical parameter.

Suspension assembly according to any of the preceding claims, wherein the detector is a peak detector 5 which is adapted to measure the peak voltage over and / or the peak current through the electric coil.

The suspension assembly of any one of the preceding claims, wherein the electrical circuit comprises a resonance circuit which incorporates the electrical coil 10.

8. Suspension assembly according to claim 7, wherein the electrical circuit is arranged such that it operates at or near a resonance frequency at a predetermined relative position of the inner tube and outer tube.

The suspension composition of claim 8, wherein the predetermined relative position corresponds to a standard position when mounted on a motorcycle.

10. Suspension assembly according to claim 9, wherein the resonance circuit can be adjusted externally to change the resonance frequency to thereby correct a change in standard position.

11. Suspension assembly according to any of claims 7-10, wherein the resonance circuit comprises a capacity for forming a series resonance LC network with the electric coil.

12. Suspension assembly according to any of claims 1-11, wherein said one of the inner tube and outer tube is the inner tube and wherein the other tube is the outer tube.

The suspension assembly of claim 12, wherein said outer tube comprises a cylinder and wherein said inner tube comprises a piston with piston rod movable in the cylinder, the cover being a protective cover for protecting a portion of the piston rod which is outside the cylinder extends.

Suspension assembly according to claim 13, wherein said cylinder comprises a hydraulic fluid for damping the telescopic movement between the cylinder and the piston rod.

15. A suspension assembly according to claim 14, further comprising a coil spring arranged between a support element fixedly connected to the inner tube and a support element fixedly connected to the outer tube.

16. Telescopic fork for a vehicle, such as a motorcycle, comprising the suspension assembly according to claim 12, wherein the inner tube and the cover can be fixedly connected to a connecting element, such as a yoke of a motorcycle, which inner tube with a frame of said vehicle and wherein the outer tube is connectable to a wheel axle.

The suspension system of any one of claims 1 to 11, wherein said one of the inner tube and outer tube is the outer tube and wherein the other tube is the inner tube.

18. A telescopic fork for a vehicle, such as a motorcycle, comprising a pair of parallel and spaced fork tube assemblies, each fork tube assembly comprising: a second inner tube and a second outer tube adapted to move telescopically relative to each other; A coil spring disposed in the fork tube assembly between a support element of the second inner tube and a support element of the second outer tube; wherein at least one fork tube assembly comprises the suspension assembly of claim 17, wherein said outer tube is fixedly connected to the second inner tube on an inner side thereof, and wherein said inner tube is fixedly connected to the second outer tube on an inner side thereof.

19. Telescopic fork according to claim 18, wherein the inner tube comprises an electrically conductive piston rod which is connected to a piston, and wherein said outer tube comprises a cylinder in which said piston is movably mounted, said piston rod being fixedly connected to the second outer tube and wherein the cylinder is fixedly connected to the second inner tube.

The telescopic fork of claim 19, wherein the cylinder is integrally connected or fixedly connected to the cover.

A telescopic fork as claimed in claim 19 or 20, wherein the cylinder is at least partially filled with a hydraulic fluid for damping the telescopic movement between the second inner tube and the second outer tube.

22. Vehicle, such as a motorcycle, comprising at least one of: the suspension composition according to any of claims 1-15 and claim 17; the telescopic fork according to any of claims 16 and 18-21.