CN-121986051-A - Fork shaft, telescopic fork and power vehicle

Abstract

The invention relates to a fork shaft for a telescopic fork, which fork shaft extends along a longitudinal axis, wherein the fork shaft has an upper bearing region and a lower bearing region, and is designed such that its surface moment of inertia in the direction of travel differs at least in some regions from its surface moment of inertia transverse to the direction of travel, and the surface moment of inertia has its minimum value in the middle region of the fork shaft.

Inventors

• M. Divald

Assignees

• 宝马股份公司

Dates

Publication Date

20260505

Application Date

20241021

Priority Date

20231120

Claims (13)

1. 1. A fork shaft (10) for a telescopic fork, The fork shaft extends along a longitudinal axis (L), Wherein the fork shaft (10) has an upper bearing region (12) and a lower bearing region (14), and The fork shaft (10) is designed such that its surface moment of inertia in the direction of travel (F) differs at least in regions from its surface moment of inertia transversely to the direction of travel, and The surface moments of inertia each have their minimum value in the middle region (20) of the fork shaft (10).
2. 2. The fork shaft (10) according to claim 1, Wherein the fork shaft (10) is designed such that the surface moment of inertia in the direction of travel (F), in particular in the middle region, is greater than the surface moment of inertia transverse to the direction of travel.
3. 3. Fork shaft (10) according to claim 1 or 2, Wherein the fork shafts (10) are designed such that the surface moment of inertia decreases in each case towards the middle region (20) of the fork shafts (10).
4. 4. Fork shaft (10) according to one of the preceding claims, Wherein the fork shaft (10) is forged or at least partially forged.
5. 5. Fork shaft (10) according to one of the preceding claims, Comprising a strip-shaped intermediate region (20) which widens towards the support region (12, 14).
6. 6. Fork shaft (10) according to one of the preceding claims, Wherein the fork shaft (10) has a plate-like structure (22) in a transition region (24) between the intermediate region (20) and the support region (12, 14).
7. 7. The fork shaft (10) according to claim 6, Wherein the plate-like structure (22) transitions into a cylindrical support region (12, 14).
8. 8. Fork shaft (10) according to one of the preceding claims, Wherein the support region (12, 14) is hollow, in particular hollow perforated.
9. 9. Fork shaft (10) according to one of the preceding claims, Comprising at least one recess (26) oriented transversely to the direction of travel (F).
10. 10. Fork shaft (10) according to one of the preceding claims, Wherein a recess (26) is formed adjacent to the strip-shaped intermediate region (20).
11. 11. Fork shaft (10) according to one of the preceding claims, Wherein a recess (26) is formed in the transition region (24) to the support region (12, 14).
12. 12. Telescopic fork comprising a fork shaft (10) according to one of the preceding claims.
13. 13. Power vehicle, in particular motorcycle, comprising a telescopic fork according to claim 12.

Description

Fork shaft, telescopic fork and power vehicle Technical Field The present invention relates to a fork shaft for a fork of a power vehicle, in particular a motorcycle, a telescopic fork and a power vehicle. Background The fork axle of a two-wheeled vehicle such as a bicycle or motorcycle is typically a cylindrical tube having a circular outer cross section. It is also known to design the outer cross section exactly to BE non-circular, whereby different mechanical properties can BE provided in different spatial directions, see for example BE 10 27 93 A1. However, it has been shown that such a solution is often insufficient, in particular in the case of telescopic forks, to enable a targeted influencing of the deflection of the lower fork bridge to the lower fork bridge and also to enable a targeted deflection of the fork beams. Disclosure of Invention The object of the present invention is therefore to provide a fork axle for a telescopic fork, a telescopic fork and a motor vehicle, wherein the fork axle is intended to achieve a targeted deformation of the lower fork bridge to the upper fork bridge and is intended to achieve a targeted deformation of the fork beam. This object is achieved by a fork shaft according to claim 1, a telescopic fork according to claim 12 and by a power vehicle according to claim 13. Further advantages and features result from the dependent claims, the description and the figures. According to the invention, a fork shaft for a telescopic fork extends along a longitudinal axis, wherein the fork shaft has an upper bearing region and a lower bearing region, and the fork shaft is designed such that its surface moment of inertia in the direction of travel differs at least in some regions from its surface moment of inertia transverse to the direction of travel, and the surface moment of inertia has its minimum value in the middle region of the fork shaft. Surprisingly, it has been shown that a targeted influence on the deformation of the lower fork bridge to the upper fork bridge and also on the deformation of the fork beams fastened in the fork bridge can thus be achieved. The telescopic fork comprises two fork bridges and two fork legs or fork beams. The two fork beams are typically composed of a prop tube and a dip tube. The fork bridge is connected through a fork shaft. Expediently, the deformation behavior of the entire fork can be influenced via the geometry of the fork shaft. It has been found that the plane moment of inertia of the fork shaft in the direction of travel, in particular in the middle region, is expediently greater than the plane moment of inertia transverse to the direction of travel. Here, "in the direction of travel" means the moment of inertia about the y-axis and "transversely to the direction of travel" means the moment of inertia about the x-axis, the x-axis being oriented in the direction of travel, the z-axis being oriented along the longitudinal axis of the fork and the y-axis being correspondingly transversely thereto. According to one embodiment, the above applies over the entire length of the fork shaft or over substantially the entire length of the fork shaft (between the bearing areas). In one aspect, the support region is for supporting the fork shaft within a frame of a corresponding vehicle. Furthermore, the fork bridge is fixed there. Typically, the support region has a circular, in particular a perfect circular, outer cross section. According to one embodiment, the fork shafts are designed such that the moment of inertia of the faces decreases in each case towards the middle region of the fork shafts. Accordingly, according to one embodiment, they each have their minimum value there. That region or section of the fork shaft that is centrally or substantially centrally located between the bearing regions is referred to as the intermediate region. The surface moment of inertia is expediently minimal here both in the direction of travel and transversely thereto. Forging has proven to be a particularly suitable method of manufacture in order to provide the desired mechanical properties of the fork shaft. The fork shaft is accordingly expediently at least partially or completely forged, in other words produced or processed in a forging method. The fork shaft may also be referred to as a forging. In particular, forging can be accomplished with very thin wall thicknesses. According to a preferred embodiment, the fork shaft comprises a strip-shaped intermediate region which widens towards the support region. The strip-shaped middle region preferably has an approximately quadrangular, preferably in particular rectangular, shape in cross section. The longer side of the rectangle is preferably oriented in the direction of travel. It is achieved that the moment of inertia of the surface in the direction of travel is greater than the moment of inertia of the surface transverse to the direction of travel. According to a preferred embodiment, the ratio between th