Abstract:
An arrangement is utilized for reducing the manual steering force associated with steering a motorcycle. A steering assist for a vehicle includes a handlebar, and the handlebar being rotatable around a center of rotation. The steering assist further includes a damping device that includes a damping chamber, and a hydraulic valve being in fluid communication with the damping chamber and includes a first shaft section and a second shaft section. The hydraulic valve also includes a bearing mounting, and a bearing mounted in the bearing mounting. The steering assist further includes an upper fork crown attached to the first shaft section of the hydraulic valve, and a lower handlebar mounting attached to the second shaft section via the bearing arranged in the bearing mounting of the hydraulic valve. The handlebar being attached to the lower handlebar mounting, and the damping device being attached to the bearing mounting and the upper fork.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit and priority to and is a U.S. National Phase of PCT International Application Number PCT/SE2006/000751, filed on Jun. 19, 2006, designating the United States of America and published in the English language, which claims priority under 35 U.S.C. § 119 to Swedish Application Number 0501416-2, filed on Jun. 20, 2005. The disclosures of the above-referenced applications are hereby expressly incorporated by reference in their entireties. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally relates to an arrangement preferably intended for motorcycles that, in association with steering, would benefit from a reduction in the steering force. The motorcycles can feature a handlebar that is rotated around a center of rotation by a steering force and damping devices that are operated by a damping medium to take up movement that is transmitted to the handlebar due to unevenness in the surface upon which the motorcycle is being driven. 
         [0004]    2. Description of the Related Art 
         [0005]    Reference is made to two-wheel drive motorcycles and to heavy motorcycles that are heavy to steer during certain driving situations. “Heavy motorcycles” as used herein means motorcycles weighing 400 kg or more. With, two-wheel drive motorcycles (that is both rear and front wheel drive), the driving characteristics differ from those of more traditional motorcycles. On severe bends, the front wheel trail (commonly known as a measurement of the distance between an axis, or spindle, of the front wheel and an intersection of the steering axis of the handlebar and the ground, which is usually forward of the steering axis due to an offset of a wheel spindle from the steering axis) causes a turning force that requires an application of large manual counter forces to the wheel. In addition, it generally is necessary to use large manual steering forces (also deflection forces) on two-wheel drive motorcycles. Moreover, large manual steering forces must be used under certain driving conditions when operating large or heavy motorcycles. 
         [0006]    Motorcycles with two-wheel drive are already known by, among other things, patent applications submitted by the applicant of the present application; see for example WO  03070554  and PCT/SE2004/001782. Heavy motorcycles are to be found in abundance on the open market. 
       SUMMARY OF THE INVENTION 
       [0007]    There is, in general, a need to improve the steering function on motorcycles and similar vehicles. An object of certain embodiments of the present invention is to solve this problem, not only for the motorcycles mentioned, but also, in general, for other motorcycles that also would benefit from such a feature. There is also a desire to be able to integrate the new function with existing components on the motorcycle or vehicle. Certain embodiments of the invention provide close interaction with existing damping devices on the vehicle. In the case of two-wheel drive motorcycles with hydraulic front wheel drive, a hydraulic unit associated with the drive also can be utilized as a power source for a servo function. In some embodiments, power sources that comprise or operate with electrical energy can be utilized. There is also a desire to increase the acceleration and to maintain the increased acceleration over an extended period of time, even when the surface upon which the vehicle is being driven is very uneven. Conventional arrangements are believed to be unable to accommodate such increased acceleration. Tests have shown reductions in engine speed from, for example, 37 seconds with motorcycles having prior constructions to 35 seconds with motorcycles that utilize certain features, aspects and advantages of the invention. 
         [0008]    In some embodiments, a servo function is provided that reduces the manual deflection force or counter force with a damping medium. In some embodiments, it is also described how this arrangement interacts with, and is mounted in relation to, vehicle-specific components, such as, for example, a front fork, a handlebar and a frame. 
         [0009]    In some embodiments, the servo function contains a device, by means of which the servo function can be actuated by turning of the handlebar. The control device is connected to a hydraulic unit that delivers hydraulic pressure or hydraulic medium pressure to assist in deflection or countering forces. The arrangement preferably comprises a valve that determines the flow direction of the hydraulic oil. In an embodiment, the damping device can consist of a blade damper. Other types of damping device, however, are possible. For example, damping devices based on cylinders and pistons also can be used. In a further configuration, a hydraulic valve also can be included, the longitudinal axis of which extends along the axis of rotation of the handlebar. The hydraulic valve is arranged to rotate around its longitudinal axis after a predetermined initial rotational movement of the handlebar. A countering device can be structured to determine the size of the initial movement. 
         [0010]    Additional further developments will be apparent from the following subsidiary claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    By means of what is proposed in the above, a technically advantageous construction, function and assembly of the servo function can be obtained. Existing components on the motorcycle can be utilized for the servo function as well as for their original function and thus, for example, a blade damper function can easily be modified for servo steering and the blade damper can be connected to the hydraulic valve in a very simple way. A currently proposed embodiment of an arrangement that has the significant characteristics of the invention will be described below, with reference to the attached drawings, in which 
           [0012]      FIG. 1  schematically shows in vertical view, a front portion of a motorcycle that is equipped with a servo function; 
           [0013]      FIG. 1   a  schematically shows in vertical view, a second embodiment of the front portion of the motorcycle, with certain parts being shown in cross section; 
           [0014]      FIG. 1   b  shows in a section taken along the line A-A in  FIG. 1 , the section showing the steering column of the motorcycle in cross section; 
           [0015]      FIG. 2  schematically shows portions of the motorcycle and blade damper device along with a control device and a hydraulic unit; 
           [0016]      FIG. 3  schematically shows another construction of the motorcycle and damper device; 
           [0017]      FIG. 4  is a top view of some of the components of  FIG. 1 ; and 
           [0018]      FIG. 5  shows a top view similar to  FIG. 4  in which the steering column has been turned. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    In  FIG. 1 , a front wheel on a motorcycle is indicated by  1 . A portion of the frame of the motorcycle is indicated in outline by frame parts  2 ,  3 . A front fork of the motorcycle is indicated by  4  and an upper fork crown and a lower fork crown are indicated by  5  and  6  respectively. The ends of the frame parts  2 ,  3  are attached to a steering column  7 . The front wheel  1  can be steered around an axis of rotation  25  that extends through a center of the steering column  7 . 
         [0020]    The upper frame part  2  is provided with a bracket  8 . A damping device, in the form of a blade damper, is indicated by  9 . A blade for the blade damper, that is not shown in  FIG. 1 , is connected to a bearing shaft  10 , that has a center of rotation that coincides with the axis of rotation  25  and that is attached to a part  11  that tapers outwards from the damper  9 . This part  11  is mounted on a pin  12  that extends out from a free end  13  of the bracket  8 . 
         [0021]    The arrangement also shows upper and lower mountings  14 ,  15  for a handlebar  16 . The upper and lower handlebar mountings  14 ,  15  are connected to the upper fork crown  5  by fixing parts  17 , one of which is shown in  FIG. 1 . The upper fork crown  5  is provided with a mounting  18 , upon which a hydraulic valve  19  is mounted. The hydraulic valve  19  has a first shaft section  20 . The first shaft section  20  fixes the valve  19  in the mounting  18 . The hydraulic valve  19  also is provided with a second shaft section  21 . 
         [0022]    The handlebar mountings  14 ,  15  also are attached to a bearing mounting  22  that is attached, together with the handlebar mountings  14 ,  15 , to the upper fork crown  5  via the bearing parts  17 . The handlebar mounting  15  and the bearing mounting  22  are in contact with each other. The handlebar mountings  14 ,  15  clamp around the handlebar  16  and give this a fixed position in relation to the horizontal part of the handlebar  16 . 
         [0023]    The bearing mounting  22  is provided with a bearing  23  that journals the shaft  21  of the hydraulic valve  19 . The second shaft section  21  (e.g., hydraulic valve shaft) extends through the bearing  23  and its end portion  21   a  is attached to the lower handlebar mounting  15 . The mountings  14 ,  15  that hold the handlebar  16  are capable of rotating relative to the bearing mounting  22 . During rotation between the handlebar mountings  14 ,  15  and the bearing mounting  22 , the second shaft section  21 ,  21   a  of the hydraulic valve  19  rotates around a central axis  24  of the hydraulic valve  19  and gives an angle of rotation α between the first and second shaft sections  20 ,  21 . 
         [0024]    The hydraulic valve  19  is thereby arranged to control or affect the flow of medium for the damping device  9 , in accordance with what is described below. The control is initiated after an initial rotational movement of the handlebar  16 . The size of this initial rotational movement can be determined by a device  26 , such as a pin, arranged in the lower handlebar mounting  15 . The device  26  extends downward and interacts with a countering device  27 . The countering device  27  is positioned in the bearing mounting, which has a space for the countering device  27 . The countering device  27  can comprise a rubber ring, a spring arrangement, a torsion spring, etc. In one embodiment, the countering device  27  is a ring made of expanded polyurethane. 
         [0025]      FIG. 1  also shows by broken lines another arrangement. In this arrangement, the outgoing bearing shaft  10 ′ of the damping device  9  extends through, and terminates outside of, the lower end of the steering column  7 . A part  11 ′ is attached to a lower end of the extended shaft  10 ′. The part  11 ′ is mounted on a pin  12 ′ that projects outward from a free end  13 ′ of a bracket  8 ′. The bracket  8 ′ is attached to the lower frame section  3 . The illustrated arrangement works in generally the same way as the arrangement described above. 
         [0026]      FIG. 2  shows the upper fork crown  5  with the front forks  4 ,  4 ′. In addition,  FIG. 2  shows the position of the damping device  9 , the part  11  and the pin  12 . The bearing shaft  10  of the blade damper  9  also is shown. A blade  28  operates in a space generally defined by partial spaces  29 ,  30  on both sides of the blade  28 . 
         [0027]    The function of the hydraulic valve  19 , in accordance with known hydraulic technology, can be considered to comprise a slide  31  that can move in a longitudinal direction and can assume three different longitudinally displaced positions in relation to hydraulic pipes  32 ,  33  and  34 . The longitudinally displaced position for the slide  31  is controlled by an electrical signal that is obtained from an electrical control device  35 . The effect on the slide  31  caused by the electrical signal is schematically indicated. In the illustrated case, the slide  31  assumes its middle position. 
         [0028]    The hydraulic valve  19  is provided with a pressure-generating part  36  and a return part or reservoir  37 . The movement of the slide  31  from the middle position shown in  FIG. 2  to each end position is symbolized by arrows  38 ,  39 . As a result of the movement in either direction caused by the signal, the movement continues as long as the signal is maintained, and, when the signal ceases, the slide  31  assumes its middle position due biasing forces of return springs  40 ,  41 . 
         [0029]    The hydraulic pipe  33  is connected to the partial space  29  via a connector  42 . In a corresponding way, the hydraulic pipe  34  is connected to the partial space  30  via a connector  43 . 
         [0030]    In  FIG. 2 , the hydraulic valve  19  assumes its middle position as long as the handlebar  16  is not moved and as long as the initial movement of the handlebar  16  does not exceed a predetermined amount. When the slide  31  is in the middle position, the partial spaces  29 ,  30  are connected to each other via the hydraulic pipes  33 ,  34  and by a duct  44  in the slide. In the middle position, the damping device  9  can work completely independently of the servo function and can carry out its damping function via damping devices such as, for example but without limitation, holes, shims, etc, arranged in the damper  9 . The function of the blade damper  9  is already well known and therefore will not be described in greater detail here. In the middle position, the pressure-generating device  36  (e.g., pump) is connected directly to the reservoir  37 . 
         [0031]    The slide  31  has a part comprising first ducts  45 ,  46 . When the handlebar  16  is turned in either direction, the slide  31  assumes the relevant end position, with the result that these ducts  45 ,  46  are aligned with the hydraulic pipes  32 ,  33 ,  34 . The pressurizing device  36  is thereby connected to the second partial space  30  in the blade damper via the duct  46 . The duct  33  is connected to the reservoir  37  via the duct  45 , which means that the partial space  29  also is connected to the reservoir  37 . The damping function of the blade damper  9  thereby is completely or at least partially inoperative and the pressure-generating device  36  changes the pressure in the partial space  30  to move the blade  28 , which assists in the servo function. During movement of the blade  28  in its space  29 ,  30 , medium is led from the second partial space  30  to the reservoir  37 . When the slide  31  assumes the second position where ducts  47 ,  48  are aligned with the hydraulic pipes  32 ,  33 ,  34 , the pressurizing device  36  is connected to the first partial space  29  and the second partial space  30  is connected to the reservoir  37 . 
         [0032]      FIG. 3  shows a different type of damping device.  FIG. 3  shows the front forks  4 ,  4 ′ and a center of rotation  49  of the fork crown  5 . A damper device  9  is utilized that comprises a cylinder  50  in which a piston  51  operates. A piston rod  52  connects to the piston  51  and connecting pipes  53 ,  54  connect to the hydraulic valve and correspond to the pipes  33 ,  34  in  FIG. 2 . 
         [0033]      FIGS. 4 and 5  show the arrangement illustrated in  FIG. 1  viewed from above and in partial cross section. As shown in  FIG. 4 , the illustrated arrangement comprises two countering devices  27 ,  27 ′ that are located at a distance from each other. The countering devices  27 ,  27 ′ and the pins  26 ,  26 ′ have the same construction. When the handlebar  16  assumes its neutral position as far as steering deflection is concerned, the pins  26 ,  26 ′ are located in the center of the respective countering devices  27 ,  27 ′.  FIG. 4  also shows the upper fork crown  5 , the front forks  4 ,  4 ′ and the lower handlebar mount  15 . In addition,  FIG. 4  shows the part  11  and the pin  12 . Similarly, it shows the position of the blade damper  9  relative to the other parts. When the handlebar  16  is given a deflection α that exceeds a particular value, the electrical control device  35  issues the electrical signal and the slide  31  in the hydraulic valve  19  is moved to control flow of fluid in the system. 
         [0034]      FIG. 5  shows an initial movement greater than a predetermined size, which means that the pin  26 , for example, has moved from a central position, such as that shown in  FIG. 4 . The movement of the pin  26  results in the adjustment of the slide  31  to the relevant end position described above. Movement of the slide  31  places the pressure-generating device  36  in fluid communication with one side of the blade  28 . As a result of the pressure-generating device  36  being connected to one side of the blade  28  and, at the same time, the medium in the partial space on the other side of the blade  28  being led away, a steering input is added to the manual steering force. The servo function that is obtained in this way thus participates in the deflecting or countering function and it is possible to obtain a reduction in the manual steering force that is required. 
         [0035]    In  FIG. 2 , a medium  37   a  used in the system, such as, for example but without limitation, hydraulic oil with any additives. The motorcycle can be driven over uneven surfaces  55 , such as those shown in  FIG. 1 . Moreover, as shown in  FIG. 2 , a switch  56  can be provided to control operation of the servo function through connection to a battery power source  57 . The pressure-generating device  36  acts upon the relevant side of the blade or piston in response to the hydraulic medium pressure that is generated by the hydraulic unit. This generation of pressure can be dependent upon the driving speed, which has advantages as far as function of the servo system is concerned. At speeds where it is necessary to add servo force to the manually-applied steering force, the servo function is more active, and vice versa. 
         [0036]      FIG. 1   a  shows parts of the arrangement in cross section, with the construction of the steering column  7  being illustrated in particular. The axis of rotation of the outgoing shaft  10  of the damping device  9  (e.g., the blade damper  9 ) preferably coincide with or essentially coincide with the axis of rotation  25 . An upper fork crown  5  is shown in  FIG. 1   a  as are upper and lower mountings  14 ,  15  for a handlebar  16 . 
         [0037]    The steering column  7 , the front fork  4  and an outer casing  58  of the illustrated hydraulic valve  19 ′ are attached to the upper fork crown  5 . A bearing  23 ′ is incorporated inside the outer casing  58 , which bearing  23 ′ enables the hydraulic valve  19 ′ to rotate around its axis of rotation  24 ′ and enables there to be an angle of rotation α between the incoming and outgoing shafts of the hydraulic valve  19 ′. 
         [0038]    A steering shaft  59  is arranged in the steering column  7 . This steering shaft  59  is mounted at its upper and lower part by bearings  60  that are supported in the outer casing of the steering column  7  or a sleeve (not shown). The upper fork crown  5  is, in turn, mounted by a bearing  61  to the upper part of the outer casing of the steering column  7  or the sleeve, so that the front wheel of the motorcycle turns in conjunction with the rotation of the handlebar  16 . 
         [0039]    The illustrated device also has two support devices  62  (only one of which is shown), that are placed symmetrically around the central axis  24 . The support devices  62  join together the upper fork crown  5  and the lower handlebar mounting  15 . Devices or pins  26 ,  26 ′ are arranged between these support devices  62  and the fork crown  5  or the lower handlebar mounting  15 . The illustrated pins  26 ,  26 ′ determine the initial rotational movement of the handlebar. The pins  26 ,  26 ′ extend down into and interact with the countering devices  27 ,  27 ′ that are arranged in corresponding parts in the fork crown  5  or the lower handlebar mounting  15 . The pins  26 ,  26 ′ and the countering devices  27 ,  27 ′ work together in the same way as described above. 
         [0040]    With continued reference to  FIG. 1   a , a part  11 ″ is attached in the upper part of the outer casing of the steering column  7  or the sleeve, which part joins together the outgoing shaft  10  of the damping device  9  and the frame parts  2 ,  3  that do not rotate when steering takes place, in such a way that the steering movement is damped and the servo effect can be obtained. This part is illustrated in  FIG. 1   b  that shows a section A-A through the upper part of the steering column  7 . 
         [0041]    The hydraulic valve and the assembled devices that are described in the second embodiment can, of course, also be used together with the first embodiment. 
         [0042]    The invention is not limited to the embodiments described above as examples, but can be modified within the framework of the following claims and concept of the invention.