Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
1999-11-30
2002-03-19
Lerner, Avraham H. (Department: 3618)
Land vehicles
Wheeled
Occupant propelled type
C180S219000
Reexamination Certificate
active
06357775
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bottom link type front wheel suspension for a motorcycle.
2. Description of Related Art
The front wheel suspension for a motorcycle is generally of a telescopic type or a bottom link type.
The telescopic type front wheel suspension is configured such that a front wheel is directly connected to a body frame by means of a damper. When using the telescopic front wheel suspension for a large-sized motorcycle, a large stroke damper, that is, a large-sized damper is required to obtain a large ascending/descending stroke of a front wheel. When using a small stroke damper, the bottom link type front wheel suspension is relatively superior to the telescopic type front wheel suspension since the stroke of the damper corresponding to the ascending/descending stroke of the front wheel can be decreased by use of the link structure.
The telescopic type suspension has an expandable structure capable of being expanded/contracted just like a telescope, and is suitable for a motorcycle having a relatively small caster angle (angle between vertical line and front fork).
For a motorcycle having a large caster angle, which is so-called an American bike, since the front fork is largely tilted in the horizontal direction, it is difficult to absorb the vertical movement amount of a front wheel by the telescopic suspension from the viewpoint of the mounting angle of the telescopic suspension. In this regard, since the bottom link type suspension is less affected by the caster angle, it is suitable for a motorcycle having a larger caster angle.
A bottom link type front wheel suspension for a motorcycle has been disclosed, for example, in Japanese Utility Model Publication No. Sho 60-15744 entitled “Front Wheel Suspension For Two-Wheeled Vehicle.” The above-described related art bottom link type front wheel suspension is classified into a leading arm type shown in FIG. 1 of the above document (hereinafter, referred to as “related art No. 1”), and a trailing arm type shown in FIG. 2 of the above document (hereinafter, referred to as “related art No. 2”).
The related art Nos. 1 and 2 will be briefly described below. It should be noted that in the following description, reference characters cited from the above document are used. The related art No. 1 is characterized in that the rear end of a leading arm 3 is connected to the lower portion of a front fork F, and a front wheel W is mounted to the front end of the leading arm 3; and the rear end of a control lever 6 is connected to the front end of a lower bridge Fb and the front end of the control lever 6 is connected to the front end of an upper bridge Fa by means of a damper A. Accordingly, the damper A is protruded forwardly from the front fork F. The related art No. 1 is also characterized in that a middle point of the control lever 6 in the longitudinal direction is connected to a middle point of the leading arm 3 in the longitudinal direction by means of a link 8.
The related art No. 2 is characterized in that the front end of the leading arm 3 is connected to the lower portion of the front fork F and the front wheel W is mounted to the rear end of the leading arm 3 , and the front end of the control lever 6 is connected to a middle point of the front fork F and the rear end of the control lever 6 is connected to the front end of the upper bridge Fa by means of the damper A. Accordingly, the upper half of the damper A is protruded forwardly from the front fork F. The related art No. 2 is also characterized in that a middle point of the control lever 6 in the longitudinal direction is connected to a middle point of the leading arm 3 in the longitudinal direction by means of a link 8.
The related art No. 1 is problematic in that since the damper A is protruded forwardly from the front fork F as described above, a space for disposing the damper A is required to be provided in front of the front fork F. This results in that arrangement of a headlamp, a meter and the like in front of the front fork F is restricted in design. The same is true for the related art No. 2.
It may be considered to dispose the damper A at the back of the front fork F, however, in this case, a fuel tank and the like are accommodated at the back of the front fork F, presenting the same restriction in design.
FIG. 15
is a view, equivalent to FIG. 2 of the above document, illustrating the principle of the related art typical bottom link type suspension. Reference numerals are newly appended to the elements in FIG.
15
.
One end of a front wheel supporting arm
102
is swingably mounted to the lower end of a front forked portion
101
; an axle
104
of a front wheel
103
is mounted to the leading end of the front wheel supporting arm
102
, a push rod
105
is erected from a middle point of the front wheel supporting arm
102
; the upper portion of the push rod
105
is connected to another link
106
extending from the upper portion of the front forked portion
101
; and the leading end of the link
106
is connected to the lower ends of a suspension spring
107
and a hydraulic damper (not shown). With this configuration, the front wheel
103
is suspended from a parallel link structure, and when the front wheel
103
is moved up or down, the axle
104
is moved from a position (1) to a position (2) or from the position (1) to a position (3).
With the above parallel link structure, the motion of the link
106
desirably follows the motion of the front wheel supporting arm
102
, that is, the motion of the axle
104
, and accordingly, the axle
104
can be desirably supported by the suspension spring
107
to which the leading end of the link
106
is connected. On the other hand, in the above parallel link structure, since the upward motion of the axle
104
simply corresponds to the compression motion of the suspension spring
107
, the characteristic of the suspension spring
107
must be simply determined depending on the motion of the axle
104
. This causes a problem in that the degree of freedom in design of the suspension spring
107
becomes poor.
Furthermore, to keep the parallel link structure, the push rod
105
must be disposed in such a manner as to be substantially in parallel with the front forked portion
101
and to be made as apart from the front forked portion
101
as possible. Accordingly, when a vehicular body is viewed from a side surface thereof, the push rod
105
becomes conspicuous, with a result that the external appearance of the front wheel suspension is degraded. To cope with such an inconvenience, it is required to adopt a structure shown in
FIG. 15
in which a protrusion member
108
is provided in front of the upper portion of the front forked portion
101
while the push rod
105
is made as close to the front forked portion
101
as possible. Consequently, as shown in FIG. 2 of the above document, the front forked portion must be designed to have a complicated triangular structure.
SUMMARY OF THE PRESENT INVENTION
An object of the present invention is to provide a bottom link type front wheel suspension capable of allowing accessories such as a headlamp and a meter to be easily arranged in front of a front fork. Furthermore, an object of the present invention is to provide a front wheel suspension for a two-wheeled vehicle, which is capable of enhancing the external appearance of the front wheel suspension without complicating a structure of a front fork and its vicinity by improving a link structure, and also enlarging the degree of freedom of the suspension spring.
To achieve the above object, according to a first aspect of the present invention, there is provided a bottom link type front wheel suspension for a motorcycle, characterized in that: a steering stem is rotatably mounted in a head pipe; a top bridge and a bottom bridge are mounted on upper and lower portions of the steering stem, respectively; upper ends of front forked portions are mounted to the top and bottom bridges; one-ends of front wheel supporting arms are connected to lower ends of t
Aika Takanori
Ito Shinji
Iwai Toshiyuki
Honda Giken Kogyo Kabushiki Kaisha
Lerner Avraham H.
LandOfFree
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