Fork leg, telescopic fork and method for adjusting the length of a fork leg

Abstract

A fork leg, comprising an outer tube and an inner tube, which extend along a longitudinal axis, wherein the inner tube has at least one fastening section for the positioning of a fork bridge, and wherein the outer tube comprises a first stop and a second stop, wherein the first stop is designed to limit the entry of the inner tube into the outer tube and the second stop to limit the removal thereof, and wherein the outer tube comprises an adjustment element by means of which the stops can be moved along the longitudinal axis in such a way that a maximum length of the fork leg can be set.

Description

[0001] Fork leg, telescopic fork and method for adjusting the length of a fork leg

[0002] The present invention relates to a fork leg for a telescopic fork, a telescopic fork and a method for adjusting the length of a fork leg.

[0003] On motor vehicles such as motorcycles, it is convenient if the riding position or ride height can be adjusted. This ensures stability for the rider, for example at traffic lights, and also maintains freedom from lean angles when driving. Vehicles with an adjustable riding position also offer the option of adapting the vehicle's riding geometry, which increases the experience of different riding modes for the rider. Typically, the riding position is achieved primarily by moving the spring base (changing the spring preload) on the spring elements. Moving the spring base changes the quasi-static force of the spring element and thus, due to the constant weight of the vehicle, the riding position. DE 10 2011 086 772 B4, for example, describes a fork leg for a motorcycle fork with an adjustment device for the spring preload.The disadvantage of this approach is that the distribution between positive and negative spring travel also changes. This means that in the low riding position the negative spring travel increases and the positive spring travel is reduced. In the high riding position the negative spring travel is reduced and the positive spring travel is increased. On the one hand, this means that when the spring base is changed, the initial spring preload at the maximum length of the spring element decreases significantly and may be lost completely. On the other hand, when the riding position is changed to adjust the vehicle's driving geometry, the spring travel distribution is changed so unfavorably that less positive spring travel is available, especially in the dynamic driving geometry setting.

[0004] It is therefore an object of the present invention to enable a length adjustment of a fork leg which should not have any influence on the fork or in particular suspension characteristics as such.

[0005] This object is achieved by a fork leg according to claim 1, by a telescopic fork according to claim 12 and by a method according to claim 13. Further advantages and features emerge from the subclaims as well as the description and the attached figures.

[0006] According to the invention, a fork leg comprises an outer tube and an inner tube which extend along a longitudinal axis, wherein the inner tube has at least one fastening section for arranging a fork bridge and wherein the outer tube comprises a first stop and a second stop, wherein the first stop is designed to limit the immersion of the inner tube into the outer tube and the second stop its emergence and wherein the outer tube comprises an adjusting element by means of which the stops can be displaced along the longitudinal axis such that a maximum length of the fork leg can be set. The fork leg is a fork leg for a so-called RSU (Right Side Up) fork. The thinner inner tube is fixedly connected to the frame of the vehicle, and the front wheel is arranged or mounted on the outer tube(s).By simultaneously moving the stops, i.e. the first stop and the second stop, the division between positive and negative travel can be maintained, even though the length of the fork leg is changed. The fact that the outer tube encompasses the first stop and the second stop does not mean that the stops necessarily have to be formed directly by the outer tube. Rather, they are, so to speak, assigned to the outer tube. The position or relative location of the stops can be expediently changed and repositioned relative to the outer tube. The aforementioned principle can be expediently used for fork legs that provide a spring function, fork legs that only provide a damping function, and fork legs in which both functionalities are combined in one fork leg.

[0007] According to one embodiment, the outer tube and the inner tube are movably mounted relative to one another via a spring element, wherein the outer tube comprises a first spring seat which can be displaced along the longitudinal axis via the adjusting element, and wherein a first end of the spring element is arranged on the first spring seat. The spring element is, for example, a suspension spring, in particular a coil spring. However, the spring element can also be an air spring element. Advantageously, the spring element as such is displaced via the adjusting element, in other words, repositioned, but advantageously not compressed. By adjusting the first spring seat, the spring element can be displaced together with the first stop and the second stop relative to the outer tube without any force being exerted on the spring element as such. The inner tube is displaced and thus also the second spring seat.The ratio of positive spring travel to negative spring travel therefore remains constant.

[0008] In order to avoid hard contact during rebound / extension, a rebound stop spring or, more generally, a damping element, for example made of a plastic such as a rubber material or Elastogran, or even a metal stop is provided on or in the area of ​​the second stop.

[0009] According to one embodiment, the second end of the spring element rests directly or indirectly on the inner tube. The inner tube is displaced together with the spring element when the length of the fork leg changes. The arrangement of the spring element on the inner tube can be realized in various ways, whereby the term “direct arrangement” does not mean that the spring element rests directly on the outer wall of the inner tube, for example. Rather, it is to be understood that the spring element rests, for example, on a spring seat or the like attached to the end of the inner tube. Spacer elements such as spacer sleeves can also be used here. The spring seat can, for example, be formed by a cover element that closes the inner tube. “End” here means the end of the inner tube that is oriented towards the frame.The first end of the spring element rests against the first spring seat, which in turn is operatively connected to the adjustment element. The first spring seat can also be provided via a spacer element, such as a spacer sleeve, which interacts with the adjustment element.

[0010] According to one embodiment, the second stop is provided by a first additional element, which extends along the longitudinal axis and is operatively connected to the adjustment element. The first additional element is thus a component that can be displaced via the adjustment element. The second stop can be displaced together with the first stop via the additional element, thereby maintaining the ratio of positive spring travel to negative spring travel. Preferably, the first spring seat is also formed on the first additional element.

[0011] According to one embodiment, the first additional element is a piston rod, a cartridge unit, or a damping sleeve. A piston rod is a rod-shaped element that extends along its longitudinal axis and typically has a piston or damping unit at its end, i.e., means provided for generating a damping effect. The damping effect is advantageously adjustable, in particular mechanically or electrically adjustable. Such piston or damping units operate with valves, shims, etc. Electrical adjustment is achieved, for example, by energizing a solenoid coil, by means of which valves can be opened or closed or via which a magnetorheological fluid can be influenced.For this purpose, the magnetic coil provided in the area of ​​the piston or damping unit is connected to a line for power, signal, and / or data transmission, which leads out from the fork leg. According to one embodiment, this is an electrical line. The aforementioned cartridge unit is also known by the English term "cartridge." This is a sleeve that extends along the longitudinal axis and is typically designed to interact with the aforementioned piston or damping unit. The aforementioned damping sleeve is understood to be a sleeve or tube that is intended to interact with the inner tube (not with a piston rod).

[0012] According to one embodiment, the first additional element cooperates with the inner tube or a second additional element which is assigned to the inner tube, wherein the second additional element is a piston rod, a cartridge unit or a damping sleeve.

[0013] The internal structure of the fork leg can therefore be designed very freely. This does not affect the functionality of adjusting the fork leg length. The piston rod can therefore be attached to either the inner or outer tube. Accordingly, the cartridge unit can be attached to either the inner or outer tube, etc.

[0014] According to one embodiment, a cartridge unit is assigned to the outer tube, which interacts with the second additional element designed as a piston rod. If a spring element is provided, the second end of the spring element is assigned to the inner tube or rests against it. The first end of the spring element rests against the cartridge unit. This comprises the first spring seat. According to another embodiment, a first additional element designed as a damping sleeve is arranged on the outer tube, which interacts with the inner tube, and wherein the second end of the spring element is directly or indirectly assigned to the inner tube. The first end of the spring element rests directly and indirectly against the damping sleeve. The damping sleeve provides the second stop on its outer circumference, which is designed to limit any rebound or displacement movement of the inner tube.The inner tube preferably has a piston or damping unit at the end in the area which interacts with the damping sleeve, which is designed to provide a damping function.

[0015] According to one embodiment, the adjusting element comprises at least the first stop. The first stop can be a contact surface or a contact element formed on the adjusting element. The outer tube is closed, for example, by a cover or a cover element. This cover can serve as an end stop, in other words as a first stop, for the inner tube. In addition, it can accommodate the piston rod or the damping sleeve. The cover can be designed as an adjusting element which is arranged so as to be displaceable relative to the outer tube or has a section which is arranged so as to be displaceable relative to the outer tube. According to one embodiment, the cover, the cover element or more generally the "cover function" is provided directly or indirectly via the forked flange arranged at the end of the outer tube.

[0016] Since the adjusting element has to absorb large forces, it is expediently designed to be lockable to the outer tube in a suitable manner.

[0017] Preferably, an adjustment unit is provided for displacing the adjustment element. The adjustment unit can be electrically, hydraulically, pneumatically, and / or mechanically operated. Depending on the design of the adjustment unit, the fork leg length can be changed even while riding. Alternatively, adjustability is also possible by providing differently dimensioned spacer elements that have different installation depths or lengths. This is a very simple implementation of the described concept. The length adjustment is then achieved using different spacer elements, meaning it cannot be done without tools. Nevertheless, it enables the riding position to be adjusted without influencing the spring or damping characteristics of the fork leg. The invention also relates to a telescopic fork, in particular to a right-side-up fork, comprising at least one fork leg according to the invention.Telescopic forks typically consist of two fork legs connected by at least one fork bridge. As already mentioned, the fork legs can have the same internal structure. Alternatively, there are also designs in which one fork leg performs the spring function, while the other fork leg performs the damping function. The basic principle of adjustment, however, remains the same for both fork legs. The principle of length adjustment is also applicable to Telelever® forks.

[0018] The invention also relates to a method for adjusting the length of a fork leg, comprising the steps:

[0019] - Providing a fork leg comprising an outer tube and an inner tube which are movably mounted relative to one another, wherein a first stop is provided for limiting an immersion movement of the inner tube into the outer tube and a second stop is provided for limiting its extrusion movement;

[0020] - Moving the stops along a longitudinal axis of the fork leg to change the maximum length of the fork leg.

[0021] The stops are moved simultaneously, ensuring that the ratio of positive to negative travel remains constant. At least one mounting section for a fork bridge is provided on the inner tube. It should be noted that the advantages and features mentioned in connection with the fork leg also apply analogously and accordingly to the procedure, and vice versa.

[0022] According to one embodiment, the outer tube and the inner tube are movably mounted relative to each other via a spring element. The method preferably comprises the step:

[0023] - Moving the spring element together with the stops. Advantageously, the stops are moved together with the spring element. During the length adjustment, the spring element is not compressed or relieved, but rather moved as a whole or repositioned together with the stops. This fully preserves the original spring characteristics. Only the length of the fork leg changes. Further advantages and features will become apparent from the following description of an embodiment of a fork leg according to the invention with reference to the accompanying figures.

[0024] They show:

[0025] Fig. 1: an embodiment of a fork leg according to the invention in two lengths;

[0026] Fig. 2: the fork leg known from Fig. 1 in the compressed state.

[0027] Fig. 1 shows two fork legs 1, the fork leg 1 shown in the right half of the image being longer by an adjustment path x than the one shown in the left half of the image. The fork leg 1 comprises an inner tube 20 which has two fastening sections 14 for the arrangement of fork bridges (not shown here). An outer tube 10 is movably mounted to the inner tube 20, said outer tube having a fork stub 70 at its end for the arrangement of a wheel axle. A first additional element 60 extends from a first stop 11 and is designed as a damping sleeve 22 in the present case. This has a second stop 12 at its end and forms a first spring seat 51. The second stop 12 serves directly or indirectly as the end stop when the inner tube 20 rebounds. In the present case, a rebound stop spring 54 is arranged in the region of the second stop 12. A spring element 50 rests against the first spring seat 51. A second spring seat 52 is formed at the end or front side of the inner tube 20.Reference numeral 64 refers to a piston or damping unit, which in this case is formed on the inner tube 20 and is intended for circumferential interaction with the damping sleeve 22. The inner tube 20 is mounted in the outer tube 10 via sliding bushings 72. Reference numeral 40 indicates an adjustment element. In this case, this is designed as a type of cover or spacer. The stops 11 and 12, as well as the first spring seat 51, can be moved along the longitudinal axis L via the adjustment element 40, whereby a maximum length of the fork leg 1 can be set or changed, cf. the adjustment path x. A comparison of the left and right halves of the image shows that the spring element 50 is not compressed or relieved. Instead, it is moved as such. In particular, the first spring seat 51 is moved along with the inner tube 20, on which the second spring seat 52 is formed.The ratio of positive spring travel to negative spring travel is advantageously not affected by the change in length. In particular, the entire damping and spring characteristics are not affected by the change in length. The adjustment element 40 is shown very schematically in the embodiment outlined here to clarify its basic functionality. The actual design will be significantly more complex than outlined here. The function of the adjustment unit, be it electrical, pneumatic, or hydraulic,

[0028] 5 mechanical and / or electrical, is not outlined here.

[0029] Fig. 2 shows the fork leg 1 known from Fig. 1 in the compressed state. It can be seen that the inner tube 20 rests against the first stop 11. The suspension spring 50 is compressed accordingly. Otherwise, the features 1e are known from Fig. 1 and will not be repeated here.

[0030] List of reference symbols

[0031] I wishbone

[0032] 10 Outer tube

[0033] II first attack

[0034] 12 second stop

[0035] 14 Fastening section

[0036] 20 inner tube

[0037] 22 Damping sleeve

[0038] 40 adjustment element

[0039] 50 spring element, suspension spring

[0040] 51 first spring seat

[0041] 52 second spring seat

[0042] 54 Rebound stop spring

[0043] 60 first additional element

[0044] 64 Piston / damping unit

[0045] 70 Fork Fist

[0046] 72 sliding bushing

[0047] L Longitudinal axis x Adjustment range

Claims

Claims 1. Fork leg (1), comprising an outer tube (10) and an inner tube (20) which extend along a longitudinal axis (L), wherein the inner tube (20) has at least one fastening section (14) for arranging a fork bridge, and wherein the outer tube (10) comprises a first stop (11) and a second stop (12), wherein the first stop (11) is designed to limit the immersion of the inner tube (20) into the outer tube (10) and the second stop (12) its emergence, and wherein the outer tube (10) comprises an adjusting element (40), by means of which the stops (11, 12) are displaceable along the longitudinal axis (L) such that a maximum length of the fork leg (1) can be set.

2. Fork leg (1) according to claim 1, wherein the outer tube (10) and the inner tube (20) are mounted movably relative to one another via a spring element (50), and wherein the outer tube (10) comprises a first spring seat (51) which is displaceable along the longitudinal axis (L) via the adjusting element (40), and wherein a first end of the spring element (50) is arranged on the first spring seat (51).

3. Fork leg (1) according to claim 1 or 2, wherein a second spring seat (52) is provided directly or indirectly via the inner tube (20).

4. Fork leg (1) according to one of the preceding claims, wherein the second stop (12) is provided via a first additional element (60) which extends along the longitudinal axis (L) and which is operatively connected to the adjusting element (40).

5. Fork leg (1) according to claim 4, wherein the first additional element (60) is a piston rod, a cartridge unit or a damping sleeve (22).

6. Fork leg (1) according to claim 4 or 5, wherein the first additional element (60) cooperates with the inner tube (20) or a second additional element which is assigned to the inner tube (20), and wherein the second additional element is a piston rod, a cartridge unit or a damping sleeve (22).

7. Fork leg (1) according to one of claims 2 to 6, wherein a cartridge unit is arranged on the outer tube (10), which cooperates with a second additional element designed as a piston rod, and wherein the cartridge unit comprises the first spring seat (51).

8. Fork leg (1) according to one of claims 4 to 6, wherein the inner tube (20) cooperates with the first additional element (60) designed as a damping sleeve (22), and wherein the damping sleeve (22) comprises the first spring seat (51).

9. Fork leg (1) according to one of the preceding claims, wherein the adjusting element (40) comprises at least the first stop (11).

10. Fork leg (1) according to one of the preceding claims, wherein the adjusting element (40) can be locked relative to the outer tube (10).

11. Fork leg (1), comprising an electrical, hydraulic, pneumatic and / or mechanical adjustment unit for displacing the adjustment element (40).

12. Telescopic fork comprising at least one fork leg (1) according to one of the preceding claims.

13. A method for adjusting the length of a fork leg (1), comprising the steps: Providing a fork leg (1) comprising an outer tube (10) and an inner tube (20) which are movably mounted relative to one another, wherein a first stop (11) is provided for limiting an immersion movement of the inner tube (20) into the outer tube (10) and a second stop (12) is provided for limiting its extrusion movement; Moving the stops (11, 12) along a longitudinal axis (L) of the fork leg (1) to change the maximum length of the fork leg (1).

14. The method according to claim 13, wherein the outer tube (10) and the inner tube (20) are mounted movably relative to each other via a spring element (50), comprising the step: Moving the spring element (50) together with the stops (11 ,

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