Front Fork Assembly, Front Fork Comprising the Same, and Motorcycle

Abstract

The present invention relates to a front fork assembly and to a front fork comprising the same. The present invention further relates to a motorcycle that is provided with such a front fork assembly or front fork. According to the invention, the front fork assembly (100; 200; 300; 400; 500; 600) comprises a tuned mass damper (150) that is fixedly attached to the unsprung section (103, 104) of the telescopic unit.

Claims

1. A front fork assembly for a motorcycle, comprising: a telescopic unit comprising a first elongated tubular section and a second elongated tubular section, wherein the first tubular section is at least partially received in the second tubular section in a slideable manner, such that the first and second tubular sections can perform a telescopic motion with respect to each other along their longitudinal axes; a resilient member configured for subjecting the telescopic motion to a spring force, said resilient member defining an unsprung section and a sprung section of the telescopic unit when this unit is mounted in said motorcycle; and a tuned mass damper comprising a mass element that is able to perform an oscillatory movement parallel to the longitudinal axes; wherein the tuned mass damper is fixedly attached to the unsprung section of the telescopic unit.

2. The front fork assembly according to claim 1, wherein the tuned mass damper comprises a mass element guiding device and a mass element, wherein the mass element guiding device is configured for guiding the mass element to allow the mass element to slide relative to the mass element guiding device when performing said oscillatory movement.

3. The front fork assembly according to claim 2, wherein the mass element guiding device comprises a housing that is elongated along a direction parallel to the longitudinal axis of the first and second tubular sections, and wherein the mass element is slideably arranged in said housing, wherein the mass element is able to slide back and forth in said housing along said longitudinal direction of said housing.

4. The front fork assembly according to claim 3, wherein the housing comprises a further resilient member arranged in between the housing and the mass element configured for subjecting the sliding movement of the mass element relative to the housing to a spring force, wherein the further resilient member preferably comprises a compressed gaseous medium and/or a spring, more preferably a resilient member made out of elastic material.

5. The front fork assembly according to claim 4, wherein the housing comprises a pair of said further resilient members arranged on respective sides of the mass element.

6. The front fork assembly according to claim 1, wherein the oscillation frequency of the mass element lies in the range between 8 and 20 Hz, more preferably between 10 and 17 Hz.

7. The front fork assembly according to claim 3, wherein the housing comprises an evacuated airtight chamber in which the mass element is slideably received.

8. The front fork assembly according to claim 3, wherein the housing comprises a liquid filled container in which the mass element is slideably received.

9. The front fork assembly according to claim 8, further comprising a bypass conduit between an upper and lower section of the container.

10. The front fork assembly according to claim 8, wherein the mass element comprises at least one through hole to allow the liquid to pass between the upper and lower section.

11. The front fork assembly according to claim 9, wherein the flow resistance of the bypass conduit and/or the at least one through hole is adjustable.

12. The front fork assembly according to claim 10, wherein the tuned mass damper comprises an adjusting element for controlling a throttle opening between the at least one through hole and the upper or lower section.

13. The front fork assembly according to claim 2, wherein the mass element guiding device comprises a guiding rod that is fixedly attached to the unsprung section of the telescopic unit, and wherein the mass element comprises a longitudinal through hole, wherein the guiding rod is arranged at least partially inside the longitudinal through hole.

14. The front fork assembly according to claim 13, wherein the guiding rod is mounted to an outside of the telescopic unit.

15. The front fork assembly according to claim 14, wherein the mass element is formed by and/or is comprised in a front mudguard and/or front fender of the motorcycle.

16. The front fork assembly according to claim 1, wherein the resilient member for subjecting the telescopic motion to a spring force is mounted in the second tubular section.

17. The front fork assembly according to claim 1, wherein the resilient member for subjecting the telescopic motion to a spring force is mounted around the first tubular section, wherein the first and second tubular sections each comprise a support, wherein the resilient member is mounted in between the supports.

18. The front fork assembly according to claim 16, wherein the resilient member for subjecting the telescopic motion to a spring force comprises a spring, an elastic material, such as Cellasto, and/or wherein the resilient member is formed by a gas cylinder.

19. The front fork assembly according to claim 1, wherein a first end of the telescopic unit is connectable to a wheel bearing axis of said motorcycle, and wherein a second end of the telescopic unit opposite to the first end is connectable to a steering device of said motorcycle, wherein the tuned mass damper is arranged in between the first end and the resilient member.

20. The front fork assembly according to claim 19, wherein the first end is formed by an end of the second tubular section.

21. The front fork assembly according to claim 20, wherein the tuned mass damper is arranged in the second tubular section.

22. The front fork assembly according to claim 21, further comprising a damper for damping the telescopic motion, said damper being arranged inside the second tubular section in between second end and the tuned mass damper.

23. The front fork assembly according to claim 19, wherein the first end is formed by an end of the first tubular section.

24. The front fork assembly according to claim 23, wherein the tuned mass damper is mounted to or in the first tubular section.

25. A front fork for a motorcycle, comprising a first and second fork member that are spaced apart in a parallel manner, wherein at least one of the fork members comprises the front fork assembly of claim 1.

26. The front fork according to claim 25, wherein the first fork member comprises: a telescopic unit comprising a first elongated tubular section and a second elongated tubular section, wherein the first tubular section is at least partially received in the second tubular section in a slideable manner, such that the first and second tubular sections can perform a telescopic motion with respect to each other along their longitudinal axes; a resilient member configured for subjecting the telescopic motion to a spring force, said resilient member defining an unsprung section and a sprung section of the telescopic unit when this unit is mounted in said motorcycle; and a tuned mass damper comprising a mass element that is able to perform an oscillatory movement parallel to the longitudinal axes; wherein the tuned mass damper is fixedly attached to the unsprung section of the telescopic unit, and wherein the second fork member comprises a further telescopic unit comprising a first elongated tubular section and a second elongated tubular section, wherein the first tubular section is at least partially received in the second tubular section in a slideable manner, such that the first and second tubular sections can perform a telescopic motion with respect to each other along their longitudinal axes.

27. The front fork according to claim 26, wherein the second fork member comprises a damper for damping the telescopic motion of the further telescopic unit.

28. A motorcycle comprising the front fork as defined in claim 25.

Description

[0033] Next, the invention will be described in more detail referring the appended drawings, wherein:

[0034] FIGS. 1A-1C illustrate a front fork having a regular configuration with an externally mounted tuned mass damper in accordance with the present invention;

[0035] FIGS. 2A-2C illustrate a front fork having an upside-down configuration with an externally mounted tuned mass damper in accordance with the present invention;

[0036] FIGS. 3A-3C illustrate a front fork having a Telelever configuration with an externally mounted tuned mass damper in accordance with the present invention;

[0037] FIGS. 4A-4C illustrate a front fork having a regular configuration with an internally mounted tuned mass damper in accordance with the present invention;

[0038] FIGS. 5A-5C illustrate a front fork having an upside-down configuration with an internally mounted tuned mass damper in accordance with the present invention;

[0039] FIGS. 6A-6C illustrate a front fork having a Telelever configuration with an internally mounted tuned mass damper in accordance with the present invention;

[0040] FIGS. 7A-7C illustrate different embodiments of a tuned mass damper according to the present invention;

[0041] FIGS. 8A and 8B illustrate cross sections of the fork members of the front fork depicted in FIG. 4; and

[0042] FIGS. 9A and 9B illustrate another embodiment of an externally mounted tuned mass damper in accordance with the present invention.

[0043] In the description below, elements or components that are identical or which have similar functionality will be referred to using the same reference signs.

[0044] FIGS. 1-3 show different embodiments of the present invention in which a tuned mass damper 150 is externally mounted. FIGS. 1A-1C illustrate a front fork 100 having a regular configuration, FIGS. 2A-2C illustrate a front fork 200 having an upside-down configuration, and FIGS. 3A-3C illustrate a front fork 300 having a Telelever configuration.

[0045] In each of these configurations, the front fork comprises a pair of fork members, i.e. a left fork member L and a right fork member R. Each of these members comprises a first tubular section 101, 102 and a second tubular section 103, 104 that can move telescopically with respect to each other. Here, first tubular section 101, 102 and second tubular section 103, 104 are part of respective telescopic units.

[0046] Fork members L, R are mutually coupled by means of a triple tree 105, also referred to a yoke. Triple tree 105 comprises two plate members 105A, 105B having appropriate through holes through which first tubular sections 101, 102 (FIGS. 1 and 3) or second tubular sections 103, 104 (FIG. 2) pass. In addition, an axis 106 is provided by which the front fork is pivotally coupled to the frame of the motorcycle. On top plate member 105A, known connection members 105C are provided to fixedly attach the first or second tubular sections to plate member 105A.

[0047] The front fork according to the invention also comprises a wheel bearing axis 107 that is, depending on the configuration, coupled to either the first 101, 102 or the second 103, 104 tubular sections.

[0048] In the Telelever configuration shown in FIGS. 3A-3C, a spring 171 and a damper 172 are also provided. However, in this configuration spring 171 and damper 172 are mounted spaced apart from the first and second tubular sections 101-104. Second tubular sections 103, 104 are coupled using a pair of first arms 180 to respective second arms 181 that are fixedly mounted to the frame of the motorcycle. The frame of the motorcycle is hingedly coupled to a pair of third arms 182, which in turn are coupled to first tubular section 101, 102.

[0049] The connection between first arms 180 and second tubular section 103, 104 comprises a plate member 105B that is fixedly attached to second tubular section 103, 104. Plate member 105B defines a pivot point 106B around which front fork 300 is able to pivot to enable steering of the motorcycle. First arms 180 are on one end fixedly connected to plate member 105B, and on another end hingedly to second arm 181, by means of a hinge 185.

[0050] Third arms 182 are hingedly coupled to the frame of the motorcycle. A spring 171 and damper 172 are hingedly mounted between third arms 182 and first arms 180, using hinges 183, 184. Third arms 182 are fixedly connected to a plate member 105A. Also this latter plate defines a pivot point 106A around which front fork 300 is able to pivot, see FIG. 3B. It should be noted that the present invention is not limited to the Telelever configuration shown in FIG. 3.

[0051] Compared to FIGS. 1-2, spring 171 is mounted at a different position relative to the telescopic unit. Here, the unsprung section of the telescopic unit also comprises the second tubular sections 103,104, whereas the first tubular sections 101, 102 are comprised in the sprung section.

[0052] The front fork according to the invention comprises a Tuned Mass Damper (TMD) that is either mounted externally (FIGS. 1-3) or internally (FIGS. 4-6). Moreover, according to the present invention, the TMD is mounted to the unsprung section of the telescopic unit. This particular placement improves the steering properties and traction of the motorcycle during heavy braking and corner entry.

[0053] Front forks 400-600 illustrated in FIGS. 4-6, respectively, correspond to front forks 100-300, with the exception that TMD 150 is now mounted internally inside a wall 110 of the relevant tubular section. For convenience, the same reference signs are used to refer to elements being identical or similar with respect to the front forks having the externally mounted TMD 150. Furthermore, the construction of TMD 150 in FIGS. 1-6 is substantially identical, apart from being mounted internally or externally.

[0054] As shown in FIG. 1C, TMD 150 comprises a container 151 in which a pair of springs 152, 155 is mounted. These springs act on a mass element 154 that is moveably mounted in container 151 by means of guiding rings 157. At both ends of mass element 154, mounting structures 153, 156 may be provided for mounting springs 152, 155.

[0055] In the embodiments in FIGS. 1-6, the container is evacuated. Therefore, spaces 158, 159 in between mass element 154 and container 151 are essentially kept at a vacuum. Due to this vacuum, the movement of mass element 154 is solely damped by springs 152, 155. Therefore, if springs 152, 155 would behave as ideal springs having no damping coefficient, the movement of mass element 154 would be essentially undamped.

[0056] FIGS. 7A-7C show embodiments of a TMD 250, 350, 450 that comprise internal damping. This damping is achieved by having a liquid inside spaces 158, 159. However, to allow mass element 154 to move sufficiently, liquid has to be exchanged between spaces 158, 159. This is achieved using a through hole 251 in mass element 154. The diameter of this hole determines the amount of damping during the motion of mass element 154 relative to container 151.

[0057] The embodiments in FIGS. 7A and 7B, corresponding to an externally mounted TMD and an internally mounted TMD, respectively, comprise an adjusting element 252 in the form of a needle. This needle is able to determine the flow resistance between through hole 251 and a radial opening 253. For the FIGS. 7A and 7B embodiments, liquid has to pass from space 159, through hole 251, through radial opening 253, inside space 158. By adjusting the position of needle 252, the passage between through hole 251 and radial opening 253 can be throttled less or more, thereby determining the amount of damping. In the FIG. 7C embodiment, needle 252 is absent. The internal damping of TMD 450 can therefore not be adjusted.

[0058] In each of the embodiment in FIGS. 7A-7C, a fill opening in container 151 is provided through which the liquid can be supplied to container 151. A sealing element 260 closes this opening after filling.

[0059] Front forks 100-600 each comprise a resilient member in the form of a spring 171 for subjecting the telescopic motion of first and second tubular sections to a spring force. For example, FIG. 8A illustrates a cross section of fork member L of FIG. 4. Fork member L comprises a first tubular section 101 and a second tubular section 103. A spring 171 is provided that provides a spring force in response to a telescopic motion between tubular sections 101 and 103. As illustrated, spring 171 is provided in first tubular section 101. In addition to spring 171, a hydraulic damper 172 is provided in second tubular section 103. This damper dampens the telescopic motion. Fork member L is known in the art.

[0060] Damper 172 comprises a nitrogen filled membrane and a bottom valve 211. It further comprises a main piston 212 that is provided with a compression and rebound shim setting. Piston 212 is connected with a spindle 214 that is fixedly attached to first tubular section 101. A sealing and bearing 213 is provided by which spindle 214 is able to actuate piston 212. Damping is achieved when first tubular section 101 moves inward relative to second tubular section 103. This will cause main piston 212 to move through a fluid, such as oil, inside damper 172. Piston 212 is provided with through openings to throttle the flow of fluid between the chambers on opposite sides of piston 212.

[0061] FIG. 8B illustrates a cross section of fork member R of FIG. 4. Compared to fork member L, it does not comprise damper 172 thereby saving space. According to the invention, this space can be used to place the TMD. The front fork in FIG. 1 therefore comprises a spring 171 in each fork member, a damper in one fork member L, and a TMD damper in the other fork member R. However, the present invention does not exclude embodiments of a front fork wherein both fork members comprise a spring 171, a TMD, and a damper 172, or embodiments wherein both fork members comprise a spring 171 and a TMD but wherein only one fork member a damper 172.

[0062] Here, it is noted that both spring 171 and damper 172 are known in the art and require no further elaboration. Although front forks 100, 200, 400, 500 have a spring that is mounted inside first tubular section 101, 102, it should be noted that it is equally possible to arrange the spring around first tubular section 101, 102. For example, first tubular sections 101, 102 and second tubular sections 103, 104 could each be provided with supports, in between which supports the spring could be mounted.

[0063] Spring 171 defines an unsprung section and a sprung section of the telescopic unit when this unit is mounted in the motorcycle. More in particular, the unsprung section in FIGS. 8A and 8B comprises each component of the telescopic unit that is configured to move relative to the motorcycle frame as a result of the telescopic movement. Hence, the unsprung section of a telescopic unit may comprise spring 171 and the second tubular section 103, 104. Furthermore, the unsprung mass of the motorcycle as a whole can be defined as the mass that is unsuspended by spring 171 and may for example comprise the mass of spring 171, second tubular sections 103, 104 (FIGS. 1A-1C) or first tubular sections 101, 102 (FIGS. 2A-2C), wheel bearing axis 107, and the front wheels of the motorcycle.

[0064] FIGS. 9A and 9B illustrate an externally mounted tuned mass damper 200 that comprises a guiding rod 201 that is fixedly connected to a mounting bracket 202 by which tuned mass damper 200 can be externally mounted to the telescopic unit. Tuned mass damper 200 further comprises a mass element 203 that is provided with a longitudinal through hole 204. As illustrated, guiding rod 201 is at least partially received in through hole 204 allowing mass element 203 to be guided while moving along a direction parallel to guiding rod 201.

[0065] Guiding rod 201 is fixedly connected to two supports 205. These supports cooperate with mounting structures 207 for the mounting of spring coils 206.

[0066] Mass element 203 can be connected to a mudguard. The present invention does however not exclude other motorcycle components to be connected to mass element 203.

[0067] Although the present invention has been described using detailed embodiments thereof, the skilled person will understand that the present invention is not limited thereto, but that modifications are possible without deviating from the scope of the invention, which is defined by the appended claims.