WO2005035349A1

WO2005035349A1 - Steering damper for a motorcycle

Info

Publication number: WO2005035349A1
Application number: PCT/NL2004/000728
Authority: WO
Inventors: Marcel Radt; Philipp Habsburg
Original assignee: Wp Suspension B.V.
Priority date: 2003-10-17
Filing date: 2004-10-15
Publication date: 2005-04-21
Also published as: NL1024569C2

Abstract

Steering damper for a motorcycle, comprising a housing (2) with a hydraulic chamber (3) which is intended to be filled with hydraulic fluid, at least one wing (7) which is rotatable about a spindle (5) and divides the chamber (3) into compartments extending on either side of the wing (7), and at least one fluid passage (12) which connects the compartments to one another. The chamber (3) is substantially rotationally symmetrical, with the spindle (5) being provided in the centre of the chamber (3), and furthermore, there is a second wing (7) which is rotatble about the spindle (5) and which, together with the first rotatable wing (7) and together with at least two separating projections (8, 9), arranged in a fixed position in the chamber (3), divides the chamber (3) into at least four compartments, at least two of the compartments being provided with fluid passages (12) connecting them to one another.

Description

Short title: Steering damper for a motorcycle

The invention relates to a steering damper in accordance with the preamble of claim 1.

A steering damper of this type is known from EP-A-240 499. In this case, the damper comprises a housing in which there is a hydraulic chamber recessed in sector form, inside which a wing can rotate with damping from hydraulic fluid located in the chamber. At the topside, the chamber is bounded by a cover. The chamber is divided into two compartments by the wing, the compartments extending on either side of the wing. The hydraulic fluid in this case has the possibility of flowing from one compartment to the other via bypass passages provided in the cover.

One drawback of this steering damper is that it is complex and expensive to produce. For example, the spindle on which the wing is provided has to be surrounded by the housing over more than 180°, and the way in which it is surrounded has to be sealed in order to prevent undesirable leakage between the compartments. Furthermore, it is difficult for the asymmetric chamber to be milled accurately into the housing and for the bypass passages, with a plurality of drilled holes oriented transversely with respect to it, to be arranged accurately in the cover. In addition, the maximum level of damping which can be achieved is limited and/or the known steering damper is relatively bulky if higher levels of damping are to be achieved. Finally, the design of the bypass passages and the plurality of drilled holes oriented transversely to it only allows stepped adjustment of the level of damping by means of a screw being screwed further into or out of the passage in order thereby to open up a larger or smaller number of drilled holes.

It is an object of the present invention to at least partially overcome these drawbacks and/or to create a usable alternative.

In particular, it is an object of the invention to provide a compact, user-friendly steering damper which is simple to produce and works well .

This object is achieved by a steering damper according to claim 1. In claim 1, the steering damper comprises a substantially rotationally symmetrical chamber with a central rotation spindle on which at least two wings are provided. The wings, together with at least two separating projections arranged in a fixed position in the chamber, divide the chamber into at least four compartments . In each case two compartments located next to one another are connected to one another by means of fluid passages. The rotational symmetry advantageously allows the structure to be compact. Using at least four compartments allows a considerable greater level of damping to be achieved in a more compact structure. In addition, the chamber can be produced in a simple way and with a high degree of accuracy, for example by being drilled out, so that any leakage between, for example, the free ends of the wings and the chamber wall is reliably prevented. The susceptibility to faults is low, partly on account of the fact that the circumferential wall part of the spindle which extends inside the chamber no longer has to be largely surrounded in a sealing manner.

In one particular embodiment, the fluid passages are provided as continuous passages running through the separating projections arranged in a fixed position. This allows a compact overall structure, in particular compared to the prior art, in which the passages are provided in the cover. Furthermore, the passages can then easily be milled or drilled out during manufacture, and continuous adjustment of the level of damping is made possible, for example by providing an adjustable throttle element in the passage, which closes off the continuous passage to a greater or lesser extent.

On account of the fact that according to the invention at least four compartments are provided, it is possible to install an adjustable throttle element at two locations. One throttle element with associated damping may in this case, for example, be fixed in the factory (for example as a function of the type of motorcycle) , while the other throttle element can be adjusted by the motorcyclist.

In a variant, at least one of the throttle elements is provided with electronic control means for setting the desired level of damping as a function of a measured parameter. The measured parameter may, for example, be the speed of the motorcycle.

The control means may in this case be designed to open up the fluid passage below a certain threshold value for the measured parameter. The threshold value is then advantageously minimized, with the result that steering at low speeds, for example, is not made unnecessarily more difficult. Furthermore, the control means may be designed to throttle the passage to an increasing extent above the specific threshold value, with the result that the threshold value then constantly increases, so that sudden steering movements as a result of an obstacle on the roadway at relatively high speeds, for example, are advantageously damped.

Further preferred embodiments are defined in the subclaims .

The invention also relates to an assembly comprising a motorcycle and a steering damper according to one of claims 21 - 25.

The invention will be explained in more detail with reference to the appended drawing, in which:

Fig. 1 shows a cross-sectional view through an embodiment of a steering damper according to the invention;

Fig. 2 shows a cross-section on line II-II in Fig. 1;

Fig. 3 shows a diagrammatic view in longitudinal section through the steering damper from Fig. 1, provided on top of a crown piece of the steering system of a motorcycle;

Fig. 4 shows a plan view of Fig. 3;

Fig. 5 shows a diagrammatic longitudinal section through a variant of a steering damper according to the invention which is installed in a steering system of a motorcycle;

Fig. 6 shows a cross section on line VI-VI in Fig. 5;

Fig. 7 shows a side view of the steering damper shown in Fig. 5;

Fig. 8 shows a perspective view of a variant embodiment of the steering damper;

Fig. 9 shows a cross-sectional view of the steering damper shown in Fig. 8;

Fig. 10 shows a cross-sectional view on line X-X in Fig. 9; and

Fig. 11 shows a perspective view of the casing part of the housing from Fig. 8.

In Fig. 1 and 2, the steering damper as a whole is denoted by reference numeral 1. The steering damper 1 comprises a housing 2 in which there is a cylindrical recessed hydraulic chamber 3.

The chamber 3 is closed off at the topside by a cover 4. A spindle 5 is mounted rotatably in the centre of the chamber 3.

Two wings 7 positioned diametrically opposite one another are provided on the spindle 5. The free ends of the wings bear against the circumferential wall of the chamber 3 in such a manner that they can still rotate freely.

Two separating projections 8 and 9 which extend downwards are formed integrally on the cover 4. In the assembled state, each separating projection 8, 9 bears in a substantially sealing manner against the circumferential wall of the chamber 3 and the circumferential wall of the spindle 5. In this way, four compartments are formed between the wings 7 and the separating projections 8, 9.

A continuous fluid passage 12 is provided in the separating projection 8. Furthermore, there is a throttle element 13 extending partway into the passage 12. The throttle element 13 is in this case formed by a pin which extends in the radial direction with respect to the spindle 5. The throttle element 13 can be moved back and forth by means of an actuating button 14 provided at the free end of the pin being turned. This allows the passage 12 to be throttled to a greater or lesser extent and thus allows the level of damping to be manually adapted as desired by a motorcyclist.

In a variant of or in addition to the manual actuating option, it is also possible to provide a drive that can be controlled by electronic control means in order to adapt the position of the throttle element 13.

A continuous fluid passage is also provided in the separating projection 9. This fluid passage is located at a different level from the passage 12 and consequently cannot be seen in the cross section illustrated in Fig. 1. A throttle element 18 which extends partway into this passage is provided. The throttle element 18 is in this case formed by a pin which extends in the axial direction parallel to the spindle 5. The throttle element

18 can be moved up and down by being turned with the aid of a tool. This allows this passage to be throttled to a greater or lesser extent and the level of damping to be adapted as desired, for example before the steering damper is fitted to the steering system of a motorcycle.

The housing 2 is provided with mounting holes 19 for attaching it to the steering system or the frame of a motorcycle. The spindle 5 extends downwards through a base part of the housing 2, where it is connected to an arm 20 which is used for attachment to the frame or the steering system of a motorcycle.

Figs. 3 and 4 show one possible way of fitting the steering damper 1 to the top of the steering system of a motorcycle. The steering system in this case comprises a steering head pin 25 which is mounted rotatably in a steering head 26. The steering head 26 is fixedly connected to the frame of the motorcycle. The steering head pin 25 is connected to crown pieces 27 and 28 positioned above and below it. The housing 2 is in this case fixedly connected to the upper crown piece 27 by means of a connection 29, while the spindle 5 is fixedly connected, via the arm 20, to the steering head 26 or the frame 30 of the motorcycle. Turning the front wheel or the handlebars connected to the crown pieces 27, 28 therefore leads to turning of the housing 2 together with the separating projections 8, 9 with respect to the spindle 5 together with the wings 7. This changes the volumetric ratio of the four compartments, with the result that hydraulic fluid accommodated in the chamber 3 is forced from one compartment to the other via the passages. This involves losses of energy, thereby producing a certain amount of damping .

Figs. 5 - 7 show a variant of the steering damper, which is installed in the steering system of a motorcycle. The steering damper 50 comprises a housing 51 with a chamber 52 which is closed off by a cover 53. A spindle 54, on which there are two wings 55, is mounted in the chamber 52. Two separating projections 56 are provided on the cover 53. Continuous fluid passages 58 provided with adjustable throttle elements 57 are arranged in the separating projections 56.

The steering system comprises a steering head pin 60 which is accommodated rotatably in a steering head 61. The steering head 61 is fixedly connected to the frame of the motorcycle. The steering head pin 60 is connected to crown pieces 62 and 63 located above and below it, respectively. The housing 51 is in this case fixedly connected to the steering head 61 by means of mounting lugs 64. The spindle 54 of the steering damper 50 is of hollow design and is non-rotatably connected to the steering head pin 60 via a splined connection 65. Turning of the front wheel or the handlebars connected to the crown pieces 62, 63 therefore leads to turning of the spindle 54 together with the wings 55 with respect to the housing 51 together with the separating projections 56. This changes the volumetric ratio of the compartments between the wings 55 and the separating projections 56, with the result that damping can take place in a similar way to the embodiment shown in Fig. 1. Therefore, in this variant the steering damper 50 is installed between the steering head 61 and the crown piece 62, with the steering head pin extending from below through the steering damper 50 into the crown piece 62. This provides a very compact structure. It is also possible to install a steering damper in this way for other types of steering dampers, for example steering dampers in accordance with the prior art.

Figs. 8 - 11 show a variant in which the steering damper comprises a casing part 80 of the housing, in which there is a recessed cylindrical chamber 81. The chamber 81 is closed off at the topside by a cover part 82. A spindle 83 with two wings 84 positioned diametrically opposite one another is mounted rotatably in the centre of the chamber 81. The free ends of the wings 84 are provided with a seal 85, by means of which they bear rotatably in a sealing manner, against the circumferential wall of the chamber 81.

Two separating projections 86 are formed integrally in the casing part 80 of the housing. In the assembled state, the separating projections 86 bear in a substantially sealing manner against the cover part 82 and the circumferential wall of the spindle 83. As a result, in this case too the chamber 81 is divided into four compartments by the wings 84 and the separating projections 86.

The separating projections 86 are substantially symmetrical in form and are both provided with a continuous recess 90 which extends in the radial direction and in which an adjustable throttle element 91 is provided. The throttle element 91 is in this case formed by a needle-shaped pin 92 accommodated in a sleeve-like holder 93. The sleeve-like holder 93 is fixedly connected to the housing. The pin 92 and the holder 93 are provided with complementary screw-thread parts, it being possible for the pin 92 to be moved back and forth in the said radial direction by means of the pin 92 being turned. For this purpose, the pin 92 is provided at its free end with a recess in which a tool piece can engage. In each separating projection 86 there is a continuous fluid passage 95 which connects the compartments located on either side of the projection to one another. As can be seen from Fig. 11, each fluid passage 95 is in this case formed by two fluid passage parts 95a, 95b which are provided at different radii and each extend from opposite side wall parts of the separating projection 86. The fluid passage parts 95a, 95b are in this case milled into the casing part 80 of the housing from above, but may also be provided in other ways and/or positions in the separating projections. The fluid passage parts 95a, 95b are connected to one another by a section of the continuous recess 90 which extends in the radial direction and in which the adjustable throttle element 91 is provided. In this way, the fluid passages 95 can be throttled to a greater or lesser extent so as to adjust the level of damping.

During intensive use of the steering damper, hydraulic fluid in the fluid chamber 81 will to some extent be heated and expand. To allow this expansion to be dealt with efficiently, there is an expansion reservoir 100 which is in communication with the hydraulic chamber 81. The expansion reservoir 100 comprises a pot-shaped housing part 101 which extends downwards from the housing 80. A separating piston 102, which can move up and down and on one side bears against the hydraulic fluid and on the other side bears against a compressible gas volume, is provided in the pot-shaped housing part 101. In a variant, the separating piston may also bear against a spring element on one side. The expansion reservoir is in this case connected to the hydraulic chamber 81 by means of a passage 103 which is drilled into the housing and opens out into that section of the continuous recess 90 which forms the connection to the fluid passage parts 95a, 95b.

Numerous variants are possible in addition to the embodiments shown. For example, it is also possible to provide more than two wings and separating projections, resulting in a correspondingly larger number of compartments. Furthermore, the fluid passages may also be provided at locations other than in the separating projections, for example in the housing wall. It is also possible for the housing of the steering damper to be integrated in one of the two crown pieces and/or in part of the steering head. In addition, it is possible for the steering damper to be provided at a different position in or on the steering system, for example against the crown piece beneath it or between the crown piece beneath it and the steering head. The hydraulic fluid with which the chamber in the housing is to be filled is formed, for example, by oil. In particular, it is possible to use an electro-rheological or magneto-rheological fluid, the flow properties of which can be altered by the influence of an electric or magnetic field. It is in this way possible to make the steering damper easy to adjust by electrical means.

Therefore, the invention provides a steering damper of very compact construction which makes it possible to achieve high levels of damping. The compactness advantageously enables the steering damper to be installed and/or integrated in a steering system.

Claims

1. Steering damper for a motorcycle, comprising: a housing (2) with a hydraulic chamber (3) which is intended to be filled with hydraulic fluid; at least one wing (7) which is rotatable about a spindle (5) and divides the chamber (3) into compartments extending on either side of the wing (7) ; at least one fluid passage (12) which connects the compartments to one another, characterized in that the chamber (3) is substantially rotationally symmetrical, with the spindle (5) being provided in the centre of the chamber (3) , and in that, furthermore, there is a second wing (7) which is rotatable about the spindle (5) and which, together with the first rotatable wing (7) and together with at least two separating projections (8, 9), arranged in a fixed position in the chamber (3) , divides the chamber (3) into at least four compartments, at least two of the compartments being provided with fluid passages (12) connecting them to one another.

2. Steering damper according to claim 1, in which at least one of the fluid passages (12) at least partially extends through one of the separating projections (8, 9) .

3. Steering damper according to claim 2, in which an adjustable throttle element (13) is accommodated in at least one of the fluid passages (12) .

4. Steering damper according to claim 3, in which the throttle element (13) is provided with actuating means (14) allowing a motorcyclist to adjust it.

5. Steering damper according to claim 4, in which the actuating means (14) are provided on the outer side of the housing (2) .

6. Steering damper according to claim 5, in which the throttle element (13) comprises a needle-shaped pin which is partially threaded, and in which the actuating means (14) comprise an actuating button which is connected to the pin in a rotationally fixed manner.

7. Steering damper according to one of claims 3-6, in which the throttle element (13) comprises a needle-shaped pin which is partially threaded, and in which the actuating means comprise at least one profiling which is provided at the free end of the pin and on which a tool can engage.

8. Steering damper according to one of claims 3 - 7, in which the throttle element is provided with electronic control means for adjusting the throttle element as a function of a parameter measured when driving, in particular the speed of the motorcycle.

9. Steering damper according to claim 8, in which the control means are designed to open the fluid passage below a specific threshold value for the measured parameter and to increasingly throttle the fluid passage above the measured threshold value, by means of an associated adjustment of the setting of the throttle element.

10. Steering damper according to one of claims 3 - 9, in which the throttle element (18) extends through the separating projection (9) substantially in the axial direction, parallel to the spindle (5) .

11. Steering damper according to one of claims 3 - 9, in which the throttle element (13) extends through the separating projection (8) substantially in the radial direction with respect to the spindle (5) .

12. Steering damper according to one of claims 3 - 11, in which the fluid passage (95) comprises two fluid passage parts (95a,

95b) which are provided at different radii, each extending from opposite side-wall parts of the separating projection (86) and which are connected to one another by a fluid passage part (90) which extends substantially in the radial direction and in which the adjustable throttle element (91) is located.

13. Steering damper according to one of claims 3 - 12, in which there are two throttle elements (91) which are located diametrically opposite one another and extend through the separating projections (86) substantially in the radial direction with respect to the spindle (83) .

14. Steering damper according to one of the preceding claims, in which the housing (2) comprises a casing part and a cover part (4), the separating projections (8, 9) being fixedly connected to the cover part (4) .

15. Steering damper according to one of claims 1 - 13, in which the housing comprises a casing part (80) and a cover part (82) , the separating projections (86) being fixedly connected to the casing part (80) .

16. Steering damper according to one of the preceding claims, in which the hydraulic chamber (81) is in communication with an expansion reservoir (100) .

17. Steering damper according to claim 16, in which the expansion reservoir (100) comprises a pot-like housing part (101) which extends downwards from the housing.

18. Steering damper according to claim 16 or 17, in which the expansion reservoir (100) is in communication with the hydraulic chamber (81) by means of at least one of the fluid passages (95) .

19. Steering damper according to one of claims 16 - 18, in which the expansion reservoir (100) comprises a separating piston (102) which is moveable up and down in a housing part and which keeps the hydraulic fluid separate from a compressible gas volume .

20. Steering damper according to one of the preceding claims, in which there are means for applying an electric or magnetic field with a sphere of influence which extends as far as into the hydraulic chamber which in this case is intended to be filled with an electro-rheological or magneto-rheological fluid.

21. Assembly comprising a motorcycle and a steering damper according to one of claims 1 - 20, in which the steering damper (50) is installed between a crown piece (62) and a steering head (61) of the motorcycle.

22. Assembly according to claim 21, in which the housing (51) of the steering damper (50) is fixedly connected to a frame of the motorcycle, and in which the spindle (54) of the steering damper (50) is fixedly connected to a steering head pin (60) which extends rotatably through the steering head (61) and is fixedly connected to the crown piece (62) .

23. Assembly of a motorcycle and a steering damper according to one of claims 1 - 20, in which the steering damper (1) is fitted against a crown piece (27) of the steering system of the motorcycle.

24. Assembly according to claim 23, in which the housing (2) of the steering damper (1) is fixedly connected to the crown piece (27) of the motorcycle, and in which the spindle (5) of the steering damper (1) is fixedly connected to a frame (30) of the motorcycle.

25. Assembly comprising a motorcycle and a steering damper according to one of claims 1 - 20, in which the housing of the steering damper is integrated with a crown piece respectively a steering head of a steering system of the motorcycle.