DE102024106419A1 - Fork leg, telescopic fork and method for adjusting the length of a fork leg - Google Patents

Abstract

Fork leg, comprising an outer tube and an inner tube which extend along a longitudinal axis, wherein the outer 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, via which the stops are displaceable along the longitudinal axis such that a maximum length of the fork leg can be set.

Description

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.

On motor vehicles, such as motorcycles, it is convenient if the ride height or ride position can be adjusted. This ensures stability for the driver, for example at traffic lights, while also maintaining the lean angle during operation. Furthermore, vehicles with an adjustable ride position offer the possibility of adapting the vehicle's driving geometry, which increases the driver's experience of different driving modes. Typically, the ride 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 ride position. DE 10 2011 086 772 B4 describes, for example, 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. 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 even be lost completely. On the other hand, when the riding position is changed to adjust the riding geometry of the vehicle the spring travel distribution is changed so unfavorably that less positive spring travel is available, especially in the dynamic riding geometry setting.

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.

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.

According to the invention, a fork leg comprises an outer tube and an inner tube which extend along a longitudinal axis, wherein the outer 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 extrusion, 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 USD (upside down) fork. The larger outer tube is fixedly connected to the vehicle frame, and the front wheel is arranged on the inner tube(s). By simultaneously moving the stops, i.e. the first stop and the second stop, the division between positive and negative suspension travel can be maintained, although the length of the fork leg is changed. The fact that the outer tube includes the first stop and the second stop does not mean that the stops must necessarily 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 conveniently changed, in particular readjusted, relative to the outer tube. The aforementioned principle can be conveniently applied to fork legs that provide a spring function, as well as to fork legs that exclusively provide a damping function, and to fork legs in which both functions are combined in a single fork leg.

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 is displaceable along the longitudinal axis via the adjustment element, 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 adjustment element, in other words, repositioned, but advantageously not compressed. By adjusting or shifting 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 exerting a force 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 remains advantageously constant.

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.

According to one embodiment, the second end of the spring element rests directly or indirectly on the inner tube at the end or end face (near or in the area of a fork leg's fork stub). The inner tube is displaced together with the spring element when the fork leg changes length. The spring element can be arranged on the inner tube 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. 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. "End" here refers to the end of the inner tube that is assigned to the wheel axle. The first end of the spring element rests on 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 sleeve or the like, which interacts with the adjustment element. The first spring seat therefore does not have to be arranged directly on the adjustment element. The first spring seat can also be provided via a separate component, such as the aforementioned spacer sleeve.

According to one embodiment, the second stop is provided by a first additional element that 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.

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 expediently 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 solenoid coil provided in the region of the piston or damping unit is connected to a line for power, signal, and/or data transmission, which is routed outward 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 an inner sleeve or inner tube that is intended to interact directly with the inner tube (not with a piston rod).

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.

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 the inner or outer tube. Accordingly, the cartridge unit can be attached to either the inner or outer tube, etc. Depending on the design, spacer sleeves or similar components can be provided.

According to a preferred embodiment, a cartridge unit is assigned to the inner tube, which interacts with the first additional element designed as a piston rod. If a spring element is provided, its second end advantageously rests against the cartridge unit. The cartridge unit thus forms the second spring seat.

According to another embodiment, a piston rod is arranged on the inner tube, which cooperates with the first additional element designed as a cartridge unit, and wherein the second end of the spring element is assigned to the inner tube. In this embodiment, the spring element is thus positioned in the inner tube. The piston rod has a piston or damping unit at its end. The damping unit can, as As already mentioned, it can also be designed so that it is electrically adjustable. For this purpose, the aforementioned cable is expediently routed downwards from the fork leg. The embodiment described here has the advantage that the cable can be easily routed downwards from the fork leg and does not have to experience or follow the relative movement of the adjustment element.

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 and act as the upper seat of the suspension spring. The cover can be designed as an adjusting element that is arranged so as to be displaceable relative to the outer tube or has a section that is arranged so as to be displaceable relative to the outer tube.

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

Preferably, an adjustment unit is provided for moving the adjustment element. The adjustment unit can be electrical, hydraulic, pneumatic, and/or mechanical. 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 designed "covers" with different installation depths or lengths. This is a very simple implementation of the described concept. The length adjustment is then achieved using different covers, and therefore cannot usually be done without tools. Nevertheless, it allows 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 an upside-down fork, comprising at least one fork leg according to the invention. Telescopic forks typically comprise two fork legs connected to each other by at least one fork bridge. As already indicated, the fork legs can have the same internal structure. Alternatively, there are also designs in which one fork leg performs the spring work, while the other fork leg performs the damping work. The basic principle of adjustment, however, remains the same for both fork legs. The principle of length adjustment is also applicable to Telelever® forks.

• - Bereitstellen eines Gabelbeins, umfassend ein Außenrohr und ein Innenrohr, welche beweglich zueinander gelagert sind, wobei ein erster Anschlag zum Begrenzen einer Eintauchbewegung des Innenrohrs in das Außenrohr sowie ein zweiter Anschlag zum Begrenzen dessen Austauchbewegung vorgesehen sind;
• - Verschieben der Anschläge entlang einer Längsachse des Gabelbeins zum Ändern der maximalen Länge des Gabelbeins.

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

• - 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;
• - Moving the stops along a longitudinal axis of the fork leg to change the maximum length of the fork leg.

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 outer 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.

• - Verschieben des Federelements zusammen mit den Anschlägen. Vorteilhafterweise werden also die Anschläge zusammen mit dem Federelement verschoben. Dieses wird bei der Längenverstellung nicht komprimiert oder entlastet, sondern als Ganzes verschoben bzw. zusammen mit den Anschlägen neu positioniert. Damit bleibt die ursprüngliche Federcharakteristik vollständig erhalten. Es ändert sich lediglich die Länge des Gabelbeins.

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:

• - Moving the spring element together with the stops. Advantageously, the stops are moved along with the spring element. The spring element is not compressed or relieved during length adjustment, 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.

• 1: eine Ausführungsform eines erfindungsgemäßen Gabelbeins in zwei Längen;
• 2: das aus der 1 bekannte Gabelbein im eingefederten Zustand.

They show:

• 1 : an embodiment of a fork leg according to the invention in two lengths;
• 2 : that from the 1 known fork leg in the compressed state.

1 shows two fork legs 1, whereby the fork leg 1 shown in the right half of the image is longer by an adjustment distance x than the one shown in the left half of the image. The fork leg 1 comprises an outer tube 10, which has two fastening sections 14 for the arrangement of fork bridges (not shown here). Movably mounted to the outer tube 10 is an inner tube 20, which has a fork stub 70 at its end or front for the arrangement of a wheel axle. A second additional element 62 in the form of a cartridge unit 22 is assigned to the inner tube 20. Such a cartridge unit 22 is also known under the term "cartridge". The cartridge unit 22 has a second spring seat 52 for a spring element 50 at its end. A first spring seat 51 is formed in the region of a first stop 11. This is designed and provided to limit an immersion movement of the inner tube 20. Extending away from the first stop 11 is a first additional element 60, which in this case is designed as a piston rod 24, which forms a second stop 12 at its end. This serves directly or indirectly as an end stop during the rebound of the inner tube 20. In the present case, a rebound stop spring 54 is arranged in the area of the second stop 12. The piston rod 24 has a piston or damping unit 64 at its end. The inner tube 20 is mounted in the outer tube 10 via sliding bushings 72. Reference numeral 40 denotes an adjustment element. In this case, this is designed as a type of cover. The stops 11 and 12 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; compare the adjustment travel x. A comparison of the left and right halves of the image clearly shows that the spring element 50 is neither compressed nor relieved. Instead, it is moved as such. In particular, the first spring seat 51 and the inner tube 20 together with the cartridge unit 22, on which the second spring seat 52 is formed, are moved together. The ratio of positive spring travel to negative spring travel is advantageously not affected by the change in length. In particular, the damping and spring characteristics are not affected by the change in length. In the embodiment outlined here, the adjusting element 40 is, as mentioned, designed as a type of cover. This is configured such that it can displace the stops 11 and 12, etc., accordingly. The actual implementation will typically be more complex than outlined here. The function of an adjusting unit, be it electrical, pneumatic, hydraulic, and/or mechanical, is not shown here.

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

In an alternative advantageous embodiment, the internal structure of the 1 and 2 sketched fork leg is exactly reversed. The first additional element is designed as a cartridge unit. This has the second stop at its end and simultaneously provides the first spring seat. The second spring seat is formed, for example, at the end of the inner tube (near the fork leg), from which a second additional element designed as a piston rod extends upwards to interact with the cartridge unit. The piston or damping unit formed at the end of the piston rod is thus positioned above the spring element, see also the 1 and 2 (which show the exact reversed arrangement). The basic structure, according to which the outer tube comprises the first stop and the 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 the adjustment element, via which the stops can be displaced along the longitudinal axis such that a maximum length of the fork leg can be set, is also the same in this embodiment. Only the design or arrangement of the additional elements and, in this context, the arrangement of the spring element has changed. Apart from that, there are other variants for the internal structure of the fork leg, whereby the adjustment principle for setting the fork leg length can advantageously always be designed the same.

List of reference symbols

1

wishbone

10

outer tube

11

first attack

12

second attack

14

Fastening section

20

inner tube

21

End stop

22

Cartridge unit

24

piston rod

40

Adjustment element

50

spring element, suspension spring

51

first spring seat

52

second spring seat

54

Rebound stop spring

60

first additional element

62

second additional element

64

Piston/damping unit

70

Fork fist

72

sliding bushing

L

Longitudinal axis

x

Adjustment range

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2011 086 772 B4 [0002]

Claims (14)

Fork leg (1), comprising an outer tube (10) and an inner tube (20) extending along a longitudinal axis (L), wherein the outer tube (10) 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 insertion of the inner tube (10) into the outer tube (20) and the second stop (12) to limit its extension, and wherein the outer tube (20) comprises an adjusting element (40), via 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. wishbone (1) after Claim 1 , wherein the outer tube (10) and the inner tube (20) are mounted so as to be movable 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). wishbone (1) after Claim 1 or 2 , wherein a second spring seat (52) is provided directly or indirectly via the inner tube (20). 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). wishbone (1) after Claim 4 , wherein the first additional element (60) is a piston rod (24), a cartridge unit (22) or a damping sleeve. wishbone (1) after Claim 4 or 5 , wherein the first additional element (60) cooperates with the inner tube (10) or a second additional element (62) which is assigned to the inner tube (10), and wherein the second additional element (62) is a piston rod (24), a cartridge unit (22) or a damping sleeve. Wishbone (1) according to one of the Claims 4 until 6 , wherein a cartridge unit (22) is arranged on the inner tube (20), which cooperates with the first additional element (60) designed as a piston rod (24), and wherein the cartridge unit (22) comprises the second spring seat (52). Wishbone (1) according to one of the Claims 4 until 6 , wherein a piston rod (24) is arranged on the inner tube (20), which cooperates with the first additional element (60) designed as a cartridge unit (22), and wherein the piston rod comprises the second spring seat (52). Fork leg (1) according to one of the preceding claims, wherein the adjusting element (40) comprises at least the first stop (11). Fork leg (1) according to one of the preceding claims, wherein the adjusting element (40) can be locked relative to the outer tube (10). Fork leg (1) comprising an electrical, hydraulic, pneumatic and/or mechanical adjustment unit for displacing the adjustment element (40). Telescopic fork comprising at least one fork leg (1) according to one of the preceding claims. A method for adjusting the length of a fork leg (1), comprising the steps of: - 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 insertion movement of the inner tube (20) into the outer tube (10) and a second stop (12) is provided for limiting its extension movement; - displacing the stops (11, 12) along a longitudinal axis (L) of the fork leg (1) to change the maximum length of the fork leg (1). Procedure according to Claim 13 , wherein the outer tube (10) and the inner tube (20) are movably mounted relative to one another via a spring element (50), comprising the step: - displacing the spring element (50) together with the stops (11, 12).