U.S. patent application number 09/796532 was filed with the patent office on 2001-10-11 for front wheel suspension apparatus.
Invention is credited to Handa, Akio.
Application Number | 20010028156 09/796532 |
Document ID | / |
Family ID | 18579432 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010028156 |
Kind Code |
A1 |
Handa, Akio |
October 11, 2001 |
Front wheel suspension apparatus
Abstract
To enlarge the up and down stroke of a front wheel without
changing the layout of a steering shaft and a tie rod. An upper arm
and a lower arm are arranged in an upward and downward manner,
respectively. The upper and lower arms are pivotably attached to a
vehicle body and respective front end portions thereof are
connected by a knuckle. The upper arm constitutes substantially a
triangular shape and is provided with a front pipe, a rear pipe and
a vehicle body attaching portion. Furthermore, a joint pipe is
provided with a ring-like portion and a ball joint is attached
thereto. A rear end portion of the vehicle body attaching portion,
an escape portion in the vicinity thereof and an attaching center B
of a cushion attaching portion provided on the joint pipe, are
respectively arranged forward from a joint center line L passing
through center A of the ball joint and orthogonal to a vehicle body
center line C.
Inventors: |
Handa, Akio; (Saitama,
JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
18579432 |
Appl. No.: |
09/796532 |
Filed: |
March 2, 2001 |
Current U.S.
Class: |
280/93.512 ;
280/124.135 |
Current CPC
Class: |
B60G 3/20 20130101; B60G
2200/144 20130101; B60G 2204/14 20130101; B62D 7/20 20130101 |
Class at
Publication: |
280/93.512 ;
280/124.135 |
International
Class: |
B60G 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2000 |
JP |
2000-058908 |
Claims
What is claimed is:
1. A front wheel suspension apparatus for a vehicle, comprising: a
suspension arm, one end of said suspension arm being pivotably
attachable to a vehicle body, said suspension arm including: an
upper arm and a lower arm separated from each other in an up and
down direction, front ends of said upper and lower arms being
connected to each other via a ball joint by a knuckle for
supporting a front wheel axle of the vehicle, said upper arm
constitutes substantially a triangular shape in plan view, a
portion of said upper arm in correspondence with a side of said
triangular shape is attached with a single vehicle body attaching
portion continuous in a front and rear direction, said vehicle body
attaching portion being pivotably attachable to the vehicle body, a
side of one apex portion of said suspension arm being opposed to
the vehicle body attaching portion and attached with the ball
joint; and a knuckle arm provided at the knuckle and a steering arm
extendable from a lower end of a steering shaft of the vehicle,
said knuckle arm and said steering arm being connected by a tie
rod; and a cushion unit interposable between said upper arm and the
vehicle body; a cushion attaching portion for connecting a lower
end portion of the cushion unit is provided at said upper arm; a
rear end portion of the vehicle body attaching portion and an
attaching center of the cushion attaching portion are respectively
arranged forward from a joint center line passing through a center
point of the ball joint and orthogonal to a center of the vehicle
body; and the tie rod is arranged rearward from the joint center
line when the tie rod is disposed at a straight line advancing
position.
2. The front wheel suspension apparatus according to claim 1,
wherein said upper arm further comprises a front pipe and a rear
pipe constituting substantially a V shape in plan view; and end
portions of expanded sides of said front pipe and said rear pipe
are connected by the vehicle body attaching portion.
3. The front wheel suspension apparatus according to claim 1,
wherein an entirety of the upper arm is a one piece structure.
4. The front wheel suspension apparatus according to claim 1,
wherein an escape portion for escaping forward from the joint
center line is provided at a rear edge portion of the upper arm in
a vicinity of the vehicle body attaching portion.
5. The front wheel suspension apparatus according to claim 2,
wherein an escape portion for escaping forward from the joint
center line is provided at a rear edge portion of the upper arm in
a vicinity of the vehicle body attaching portion.
6. The front wheel suspension apparatus according to claim 3,
wherein an escape portion for escaping forward from the joint
center line is provided at a rear edge portion of the upper arm in
a vicinity of the vehicle body attaching portion.
7. A suspension arm for a front wheel suspension apparatus for a
vehicle, said suspension arm being pivotably attachable to a
vehicle body, comprising: an upper arm and a lower arm separated
from each other in an up and down direction, front ends of said
upper and lower arms being connected to each other via a ball joint
by a knuckle for supporting a front wheel axle of the vehicle, said
upper arm constitutes substantially a triangular shape in plan
view, a portion of said upper arm in correspondence with a side of
said triangular shape is attached with a single vehicle body
attaching portion continuous in a front and rear direction, said
vehicle body attaching portion being pivotably attachable to the
vehicle body, a side of one apex portion of said suspension arm
being opposed to the vehicle body attaching portion and attached
with the ball joint; a knuckle arm provided at the knuckle and a
steering arm extendable from a lower end of a steering shaft of the
vehicle, said knuckle arm and said steering arm being connected by
a tie rod; a cushion attaching portion for connecting a lower end
portion of a cushion unit of the suspension apparatus is provided
at said upper arm; a rear end portion of the vehicle body attaching
portion and an attaching center of the cushion attaching portion
are respectively arranged forward from a joint center line passing
through a center point of the ball joint and orthogonal to a center
of the vehicle body; and the tie rod is arranged rearward from the
joint center line when the tie rod is disposed at a straight line
advancing position.
8. The suspension arm according to claim 7, wherein said upper arm
further comprises a front pipe and a rear pipe constituting
substantially a V shape in plan view; and end portions of expanded
sides of said front pipe and said rear pipe are connected by the
vehicle body attaching portion.
9. The suspension arm according to claim 7, wherein an entirety of
the upper arm is a one piece structure.
10. The suspension arm according to claim 7, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
11. The suspension arm according to claim 8, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
12. The suspension arm according to claim 9, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
13. A suspension arm for a front wheel suspension apparatus for a
vehicle, said suspension arm being pivotably attachable to a
vehicle body, comprising: an upper arm and a lower arm separated
from each other in an up and down direction; a knuckle for
supporting a front wheel axle of the vehicle, said knuckle
connecting front ends of said upper and lower arms to each other
via a ball joint, said upper arm constitutes substantially a
triangular shape in plan view, a portion of said upper arm in
correspondence with a side of said triangular shape is attached
with a single vehicle body attaching portion continuous in a front
and rear direction, said vehicle body attaching portion being
pivotably attachable to the vehicle body, a side of one apex
portion of said suspension arm being opposed to the vehicle body
attaching portion and attached with the ball joint; and a rear end
portion of the vehicle body attaching portion is arranged forward
from a joint center line passing through a center point of the ball
joint and orthogonal to a center of the vehicle body.
14. The suspension arm according to claim 13, wherein said upper
arm further comprises a front pipe and a rear pipe constituting
substantially a V shape in plan view; and end portions of expanded
sides of said front pipe and said rear pipe are connected by the
vehicle body attaching portion.
15. The suspension arm according to claim 13, wherein an entirety
of the upper arm is a one piece structure.
16. The suspension arm according to claim 13, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
17. The suspension arm according to claim 14, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
18. The suspension arm according to claim 15, wherein an escape
portion for escaping forward from the joint center line is provided
at a rear edge portion of the upper arm in a vicinity of the
vehicle body attaching portion.
19. The suspension arm according to claim 13, further comprising a
cushion attaching portion for connecting a lower end portion of a
cushion unit of the suspension apparatus, said cushion attaching
portion being provided at said upper arm, and an attaching center
of the cushion attaching portion is arranged forward from the joint
center line.
20. The suspension arm according to claim 13, further comprising a
knuckle arm provided at the knuckle and a steering arm extendable
from a lower end of a steering shaft of said vehicle, said knuckle
arm and said steering arm being connected by a tie rod, the tie rod
being arranged rearward from the joint center line when the tie rod
is disposed at a straight line advancing position.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention:
[0002] The present invention relates to a double wishbone type
front suspension apparatus. In particular, the present invention
relates to a double wishbone type front suspension apparatus for a
saddle ride type all terrain vehicle such as a four wheel
buggy.
[0003] 2. Description of Background Art:
[0004] Japanese Examined Utility Model Publication No. H7-23285
discloses a double wishbone type front wheel suspension apparatus
of a four wheel buggy. According to the above front wheel
suspension apparatus, suspension arms pivotably attached to a
vehicle body are arranged in an upward and downward manner.
Furthermore, a knuckle is attached to front ends of the respective
arms via ball joints and a knuckle arm provided to the knuckle and
a steering arm extending from a lower end of a steering shaft are
connected by a tie rod. In addition, the tie rod is arranged on
rear sides of the suspension arms in plan view. Furthermore, by
bending a rear side of an upper arm provided on an upper side of
the suspension arms to a lower side and passing the tie rod by
utilizing the bent portion, interference between the tie rod and
the upper arm is avoided.
[0005] FIG. 7 of the present invention illustrates a plan view of
an upper arm constituting another embodiment. According to this
embodiment of the upper arm, by connecting a front pipe 1 and a
rear pipe 2 substantially in a V shape and connecting middle
portions of the two pipes by a cross pipe 3, the upper arm is
referred to as an A arm which constitutes substantially an A shape
as a whole. A ring portion 4 is provided at a front end portion of
the upper arm, connected to a knuckle via a ball joint, not
illustrated, attached thereto. Furthermore, respective base
portions of the front pipe 1 and the rear pipe 2 are respectively
provided with a front side vehicle body attaching portion 5 and a
rear side vehicle body attaching portion 6 to pivotably attach the
upper arm to a vehicle body.
[0006] When a joint center line L is drawn to pass a ball joint
center A constituting the center of the ball joint attached to the
ring portion 4 orthogonally to a vehicle center line C in a front
and rear direction, the joint center line L intersects with the
rear side vehicle body attaching portion 6 and a rear end 7 of the
rear side vehicle body attaching portion 6 is extended rearward
from the joint center line L. Furthermore, an attaching center B
constituting a center of a cushion attaching portion 8 provided at
an upper face of the upper arm is disposed rearward from the joint
center line L.
[0007] In addition, when the rear portion of the upper arm is bent
as in Japanese Examined Utility Model Publication No. H7-23285,
mentioned above, it is advantageous, since the tie rod and the
upper arm can be arranged proximate to each other. However, the
forming of the bent portion is complicated. Accordingly, it is not
preferable to provide a bent portion in view of the fabrication
thereof
[0008] When the upper arm is constructed as in the example of FIG.
7, it is unnecessary to bend the rear pipe 2. However, in an all
terrain vehicle such as a four wheel buggy, it is sometimes desired
to increase an up and down stroke of the front wheel suspension
apparatus and enlarge the diameter of the front wheel. In this
case, if the upper arm of FIG. 7 is used for that purpose, since
the joint center line L intersects with the upper arm in plan view,
when the up and down stroke of the front wheel is increased,
interference of the upper arm with the tie rod may occur.
Accordingly, the increase in the up and down stroke is restricted.
Furthermore, the tie rod is moved in the front and rear direction
during turning. Therefore, depending on a position of the attaching
center of the cushion attaching portion, there is also a concern
that the tie rod will interfere with the cushion unit.
[0009] In addition, when it is desired to enlarge the diameter of
the front wheel, a position of the axle must be moved toword the
front side. However, when the position of the axle is simply moved
to the front side, in order to avoid interference between the upper
arm and the tie rod, it becomes necessary to change a position of
the steering shaft or an inner side end portion (inner portion of
the side of the steering shaft) of the tie rod. However, the change
of the steering shaft causes a change in riding attitude and
accordingly, the change is not preferable. Furthermore, on the rear
side of the tie rod, there are arranged an engine and accessories
thereof. Therefore, the change with regard to the position of the
inner side end portion of the tie rod is also not preferable since
a large-scale change of the vehicle body layout becomes
necessary.
SUMMARY OF THE INVENTION
[0010] In view of the above, it is an object of the invention to
resolve the above problems. In order to resolve the above-described
problems, according to a first aspect of present invention, there
is provided a front wheel suspension apparatus wherein one end of a
suspension arm is pivotably attached to a vehicle body. The front
wheel suspension apparatus includes an upper arm and a lower arm
separated from each other in an up and down direction. Front ends
of the upper and lower arms are connected via a ball joint by a
knuckle which is for supporting a front wheel axle. A knuckle arm
provided at the knuckle and a steering arm extended from a lower
end of a steering shaft, are connected by a tie rod. Furthermore, a
cushion unit is interposed between the upper arm and the vehicle
body, wherein the upper arm constitutes substantially a triangular
shape in plan view. In addition, a portion of the upper arm in
correspondence with a side of the triangular shape is attached with
a single vehicle body attaching portion continuous in a front and
rear direction as a portion pivotably attached to the vehicle body.
A side of one apex portion of the triangular shape opposed to the
vehicle body attaching portion, is attached with the ball joint and
a cushion attaching portion for connecting a lower end portion of
the cushion unit is provided in a vicinity thereof. Furthermore, a
rear end portion of the vehicle body attaching portion and an
attaching center of the cushion attaching portion are respectively
arranged forward from a joint center line passing through a center
point of the ball joint and orthogonal to a center of the vehicle
body. In addition, the tie rod is arranged rearward from the joint
center line when the tie rod is disposed at a straight line
advancing position.
[0011] The rear end portion of the vehicle body attaching portion
and the attaching center of the cushion attaching portion are
respectively arranged forward from the joint center line.
Accordingly, even when the front wheel carries out a significant up
and down stroke, the rear edge portion of the vehicle body
attaching portion and the cushion attaching portion do not
interfere with the tie rod. Furthermore, even when the tie rod is
moved in the front and rear direction when making a turn, the tie
rod does not interfere with the cushion unit. In addition, when it
is desired to move the position of an axle forward from a
conventional position, even when the tie rod connected to the
knuckle arm is advanced along with the axle without changing the
position of the steering shaft, the interference with the upper arm
can be avoided. The position of the axle can be made movable to the
front side without changing inner side positions of the steering
shaft and the tie rod.
[0012] Accordingly, larger up and down stroke of the front wheel
can be ensured without requiring a change in the vehicle riding
attitude or a significant change in the vehicle body layout and
movement of the position of the axle is facilitated. Therefore, a
large diameter formation of the front wheel is facilitated. As a
result, there is provided a front wheel suspension apparatus that
is preferable for an all terrain vehicle such as a four wheel
buggy.
[0013] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0015] FIG. 1 is a plan view showing a plan layout of an upper arm
according to a first embodiment of the present invention;
[0016] FIG. 2 is a view showing essential portions of a side of a
vehicle body of a four wheel buggy according to the first
embodiment;
[0017] FIG. 3 is a view showing a front wheel suspension apparatus
according to the first embodiment from a front side;
[0018] FIG. 4 is a view showing the front wheel suspension
apparatus according to the first embodiment from a side;
[0019] FIG. 5 is a sectional view of essential portions of an upper
arm of the first embodiment;
[0020] FIG. 6 is a plan view of an upper arm according to a second
embodiment; and
[0021] FIG. 7 is a view of an upper arm in a conventional example
in correspondence with FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] An explanation will now be given of a first embodiment of
the present invention with reference to the accompanying drawings.
FIG. 1 through FIG. 5 relate to a first embodiment of the present
invention. FIG. 1 is a plan view illustrating a plan layout of an
upper arm and a tie rod according to the first embodiment. FIG. 2
is a view showing essential portions of a side of a vehicle body in
a four wheel buggy according to the first embodiment. FIG. 3 is a
view showing the front wheel suspension apparatus of the first
embodiment from a front side. FIG. 4 is a view showing the front
wheel suspension apparatus according to the first embodiment from a
side. FIG. 5 is a sectional view of essential portions of the upper
arm of the first embodiment. Furthermore, in the present invention,
front side, rear side, left and right and up and down, as a rule,
are indicated in accordance with the direction of advancing of the
vehicle. In addition, an inner side is referred to as a center side
of the vehicle in a similar manner.
[0023] First, an outline explanation will be given of a total
structure of a four wheel buggy to which the first embodiment is
applied. In FIG. 2, an upper frame 11 and a lower frame 12 are
arranged above and below an engine 10 arranged at the center of the
vehicle in the front and rear direction. The upper frame 11 and
lower frame 12 are connected by a front pipe 13 in the up and down
direction between front end portions thereof and are connected by
an inclined down frame 14 at a remote location rearward therefrom.
Furthermore, the front pipe 13 and the inclined down frame 14 are
connected by a reinforcing frame 15 arranged in the front and rear
direction. The vehicle body structures are provided in left and
right pairs.
[0024] Double wishbone type front wheel suspension apparatus 16 are
provided on the left and on the right of the vehicle body to front
sides of the vehicle body surrounded by the lower frames 12, the
front pipes 13, the down frames 14 and the reinforcing frames 15. A
suspension arm of the front suspension apparatus 16 is constituted
by an upper arm 17 and a lower arm 18. The reinforcing frame 15 is
provided with a bracket 19 for pivotably connecting the upper arm
17, and similar brackets 20 and 21 for the lower arm 18 are
provided at a front end portion of the lower frame 12 and a lower
end portion of the front pipe 13.
[0025] Front ends of the upper arm 17 and the lower arm 18
projected to the side are connected in the up and down direction by
a knuckle 22 and a front wheel axle 23 is projected from and
supported by a center thereof. The front wheel axle 23 extends from
both left and right sides of a front wheel differential gear 24
supported at a front end portion of the lower frame 12 and is
connected to a front wheel 25 attached with the knuckle 22 for
driving in rotation therewith.
[0026] A knuckle arm 26 projecting toward the rear side is
integrally provided at a middle portion of the knuckle 22 in the up
and down direction and a steering arm 28 extending from a lower end
portion of a steering shaft 27 disposed on an upper side thereof in
side view, to the rear side, is connected by a tie rod 30. The
steering shaft 27 is arranged obliquely in the up and down
direction such that an upper side thereof is inclined to the rear
side on a vehicle center line C (FIG. 1) in a vehicle width
direction. The steering shaft 27 is pivotably supported by a stay
31 provided above a front end portion of the upper frame 11 and
pivotable by a handle 32 attached to an upper end thereof.
[0027] A rear end portion of a vehicle attaching portion, as will
be described later, of the upper arm 17, is disposed substantially
directly above the front wheel axle 23 and on a front side of a
lower end portion of the steering shaft 27. An upper face thereof
is connected with a lower end portion of a front cushion unit 33
constituting the front wheel suspension apparatus 16. An upper end
portion of the cushion unit 33 is supported by a bracket 34
provided at the front end portion of the upper frame 11.
[0028] The lower arm 18 is constructed by a structure similar to
that of a conventional one. In particular, a width of the lower arm
18 is much wider than that of the upper arm 17, and a vehicle
attaching portion thereof is provided to respective end portions
thereof expanded to constitute a V shape substantially
symmetrically in the front and rear direction from a knuckle
connecting portion of a front end thereof. The vehicle attaching
portion on the rear side is disposed at a position rearward from
the steering arm 28 as shown by the bracket 21. Specifically, the
width of the lower arm 18 is about twice as much as the width of
the upper arm 17. Conversely, the upper arm 17 is constructed by a
structure in which the width is significantly narrower than that of
the lower arm 18.
[0029] Furthermore, notation 35 in the drawings, designates a front
wheel propeller shaft for transmitting drive force from the engine
10 to the front wheel differential gear 24, 36 designates a rear
wheel propeller shaft for transmitting the drive force from the
engine 10 to a rear wheel differential gear 37, 38 designates a
rear wheel, numeral 39 designates a rear cushion unit of a rear
wheel suspension apparatus, 40 designates a fuel tank, 41
designates a seat, 42 designates an oil cooler constituting a
portion of engine accessories and 43 designates a cooling fan
thereof.
[0030] An explanation will now be provided for the upper arm 17. As
shown by FIG. 1 and FIG. 5, the upper arm 17 is constituted
substantially in a triangle shape in plan view as a whole by
combining a front pipe 50 and a rear pipe 51 substantially in a V
shape in plan view. Furthermore, respective one end portions of the
front pipe 50 and the rear pipe 51 are connected together at an
acute angle. Furthermore, the expanded other end side portions of
the front and rear pipes 50 and 51 are connected together by a
vehicle body attaching portion 52 constituting one piece of a
pipe.
[0031] The front pipe 50 and the rear pipe 51 are pipe members
comprising pertinent material such as iron and are coupled at an
acute angle constituting substantially a V shape by fitting and
integrating respective front end side end portions thereof to a
joint pipe 53 provided by pertinent fabrication method such as
casting. A ring-like portion 54 is provided on a front end side of
the joint pipe 53 and a ball joint 55 (FIG. 5) is fitted thereto
and supported thereby. An attaching leg projects from the ball
joint 55 and is coupled to an upper end portion of the knuckle
22.
[0032] Furthermore, a bracket 56 constituting a cushion attaching
portion for coupling a lower end portion of the front cushion unit
33, is attached to an upper face of the joint pipe 53 by welding.
The bracket 56 is provided with a pair of opposed wall portions 56a
and 56b by constructing the bracket 56 substantially in a
channel-like shape. A lower end portion of the front cushion unit
33 contained between the pair of wall portions 56a and 56b, is
pivotably attached to the bracket 56 by a bolt 57 and a nut 58.
[0033] Furthermore, when a center of a rolling face of the ball
joint 55 attached to the ring-like portion 54, is defined as center
A, assuming a straight line passing through this point and
orthogonal to the vehicle center line C, the straight line is
defined as a joint center line L. Relative to the joint center line
L, a rear head portion 52a of the vehicle attaching portion 52 is
disposed on or forward from the line L.
[0034] Furthermore, attaching center B constituting a middle point
of the pair of opposed wall portions 56a and 56b of the bracket 56,
is also disposed forward from the joint center line L. The
attaching center B is also a middle point in the length direction
of the bolt 57 between the pair of opposed wall portions 56a and
56b of the bracket 56.
[0035] The vehicle attaching portion 52 is a single piece of
pipe-like member. A through collar 59 is inserted into the vehicle
attaching portion 52. A bush 60 is interposed between outer
peripheries of two ends in the length direction of the collar 59
and an inner face of the vehicle body attaching portion 52. The
vehicle body attaching portion 52 coupled with the front arm 50 and
the rear arm 51, is pivotable around the collar 59 by the bush 60.
Furthermore, a seal 61 is attached to an end portion of the bush 60
and a cap 62 is made to cover an outer side thereof.
[0036] A positional relationship among the vehicle body attaching
portion 52, the ring-like portion 54 and the like is set such that
the joint center line L passes on or rearward from the cap 62.
Furthermore, the positional relationship is set such that the joint
center line L passes rearward from the rear end portion 52a of the
vehicle body attaching portion 52 even when a position of the joint
center line L relative to the upper arm 17 is disposed on the
frontmost side. The vehicle attaching portion 52 is pivotably
attached to the bracket 19 by a bolt 63 passed through an inner
side of the collar 59 and a nut 64.
[0037] The rear pipe 51 is provided obliquely inclined to the front
side toward the inner side of the vehicle body relative to an axial
line of the vehicle body attaching portion 52. A portion of a rear
edge portion of the rear pipe 51 to the side of the vehicle body
attaching portion 52 constitutes an escape portion 65 remote from
the joint center line L to the front side. A range of forming the
escape portion 65 is constituted by almost all of a portion thereof
from a base portion side connected to the vehicle body attaching
portion 52 to the joint pipe 53 in the length direction of the rear
pipe 51. However, the escape portion 65 can arbitrarily be set in
accordance with the specification such as an arrangement of the tie
rod 30.
[0038] In FIG. 1, the position of the tie rod 30 shown by bold
lines is a position in plan view when the vehicle advances on a
straight line. As is apparent in the drawing, the tie rod 30 is
arranged substantially in parallel with the joint center line L.
One end of the tie rod 30 is connected to the knuckle arm 26 by a
pillow ball type joint 66 and the other end thereof is connected to
the steering arm 28 by a similar joint 67.
[0039] The steering arm 28 constitutes substantially a triangle
shape in plan view in the vicinity of the vehicle center C. A lower
end of the steering shaft 27 is attached to a portion of the
steering arm 28 constituting an apex corresponding portion of the
triangular shape and projected to the front side. A pair of left
and right joint attaching portions are provided on both end sides
of a portion of the steering arm 28 corresponding to a side opposed
to the apex corresponding portion and the left and right tie rods
30 (right side one relative to vehicle body is omitted) are
connected thereto via the joints 67. Furthermore, as shown by FIG.
4, a pivoting face P of the steering arm 28 constitutes an inclined
face elevated to the front side by an angle .theta. relative to a
horizontal line H. The inclination angle is larger than an
inclination angle of an attaching axial line D of the vehicle body
attaching portion 52.
[0040] Referring back to FIG. 1, when the steering shaft 27 is
pivoted, the steering arm 28 is pivoted along a locus T1.
Accordingly, the joint 67 constituting a connecting point is moved
on the locus T1. Therefore, the tie rod 30 is moved in the left and
right direction and front and rear direction of the drawing.
Furthermore, the knuckle arm 26 is pushed and pulled and pivoted
along a locus T2 around a pivoting center shaft of the knuckle 22
passing through the center A of the ball joint 55. Accordingly, the
tie rod 30 is also moved in the front and rear direction and left
and right direction and is changed to a turning position. As a
result, the front wheel 25 becomes steerable.
[0041] A right turn position of the tie rod 30 is designated by 30R
in FIG. 1 and a left turn position thereof is designated by 30L,
which are respectively exemplified by imaginary lines. In the case
of a right turn, the tie rod 30 is pulled to the right side of the
drawing. Furthermore, an end portion thereof on the side of the
joint 66 gradually approaches the bracket 56 and is disposed at a
position partially overlapping the upper arm 17 in plan view when
the tie rod 30 turns further.
[0042] In a front view of the front wheel suspension apparatus 16,
the tie rod 30 is arranged to substantially overlap the arm 17.
However, since the tie rod 30 is longer than the upper arm 17,
pivotal movement of the front wheel 25 accompanied by up and down
movement thereof, is carried out along a locus T3 centering on the
joint 67. In addition, the upper arm 17 is shorter than the tie rod
30. The upper arm 17 is pivoted along a locus T4 having a smaller
radius of curvature than that of a center of pivotal movement by
the side of the vehicle body attaching portion 52.
[0043] Furthermore, the upper arm 17 and the lower arm 18
constitute a rectangular link among the vehicle body frames (12,
13, 15) and the knuckle 22. Therefore, the front wheel 25 is moved
in parallel with the up and down direction and a state of
overlapping of the upper arm 17 and the tie rod 30 in front view is
changed. At this occasion, the pivotal movement at the front end
side of the tie rod 30 accompanied by the up and down movement of
the front wheel 25 is carried out along the locus T3 having a
pivoting radius longer than that of the arm 17 centering on the
joint 67. In addition, since the upper arm 17 is shorter than the
tie rod 30, the upper arm 17 is pivoted along the radius T4 having
a radius of curvature smaller than that of the pivotal movement
center by the side of the vehicle body attaching portion 52.
[0044] The knuckle 22 is contained in an inner side space provided
in a wheel 68 of the front wheel 25 and is connected to the front
wheel 25 by fixing the front wheel axle 23 to the wheel 68 by a nut
69. Furthermore, a brake hose 70 is arranged to intersect upper
sides of the tie rod 30 and the upper arm 17 in plan view (FIG. 1).
One end of the brake hose 70 is connected to a master cylinder
provided at a brake lever of the handle 32 (not illustrated) and
other end thereof is connected to a brake caliper (not illustrated)
in the wheel 68. By arranging the brake hose 70 in this way,
interference with the tie rod 30 is avoided.
[0045] An explanation will now be given of the operation of the
first embodiment. In FIG. 3, when the front wheel 25 carries out an
up and down stroke, the joint 66 at the front end of the tie rod is
moved on the locus T3 and the ball joint 55 at the front end of the
upper arm moves on the locus T4. The loci T3 and T4 constitute
different curves since the tie rod 30 is longer. Accordingly, with
respect to the same stroke, the pivoting angle of the arm 17 is
larger than that of the tie rod 30. When the up and down stroke of
the front wheel 25 is increased, there is brought about a state in
which the tie rod 30 intersects with the tie rod 30 in the
drawing.
[0046] However, as shown by FIG. 1 and FIG. 4, the escape portion
65 of the rear pipe 51 in the upper arm 17 and the rear end portion
52a of the vehicle body attaching portion 52 thereof and the
attaching center B of the cushion attaching portion 56, are
respectively disposed frontward from the joint center line L.
Accordingly, such interference is avoided. Therefore, a larger up
and down stroke of the front wheel 25 can be realized without
changing respective positions of inner side end portions of the
steering shaft 27, the steering arm 28 and the tie rod 30 and by
leaving the respective portions at conventional positions.
[0047] Furthermore, when the handle is turned significantly for
making a right turn, in FIG. 1, there is brought about a state in
which the side of the knuckle arm 26 constituting the front end
side of the tie rod 30, is pivoted to the front side and overlaps
the rear pipe 51 in plan view. In this case, as shown by FIG. 4,
the further the front end side, the further the tie rod 30 leaves
from the upper arm 17 to the lower side, a side of the vehicle body
attaching portion 52 of the rear pipe 51 approaches the tie rod 3
substantially at the same height. However, by presence of the
escape portion 65 and the attaching center B of the cushion
attaching portion 56 which are disposed forward from the joint
center line L, the interference is not produced.
[0048] Furthermore, even when the position of the front wheel axle
23 is moved to the front side, the knuckle arm 27 is moved to the
front side in accordance therewith and the tie rod 30 is connected
to the knuckle arm 26 that has moved to the front side.
Accordingly, by the presence of the rear end portion 52a of the
vehicle body attaching portion and the escape portion 65 and the
attaching center B of the cushion attaching portion 56 which are
disposed forward from the joint center line L, interference between
the tie rod 30 and the upper arm 17, particularly the rear pipe 51
can be avoided. Therefore, the inner side positions of the steering
shaft 27 and the tie rod 30 need not be changed. Therefore, the
vehicle riding attitude needs not be changed.
[0049] Furthermore, even when an engine accessory such as the front
wheel differential gear 24 is proximately arranged to front sides
of the steering arm 28 and the tie rod 30 and engine accessories
such as the oil cooler 42 and the cooling fan 43 are proximately
arranged on rear sides thereof, vehicle body layout of these need
not change significantly. Accordingly, a larger up and down stroke
of the front wheel 25 can easily be ensured and movement of a
position of the front wheel axle 23 is facilitated. Therefore, a
large diameter formation of the front wheel 25 is facilitated. As a
result, there is provided the front wheel suspension apparatus
preferable for an all terrain vehicle such as a four wheel
buggy.
[0050] Furthermore, since the vehicle body attaching portion 52 is
not divided forwardly and rearwardly as in the conventional
example, but is constituted by a single member continuous in front
and rear direction and therefore, relative to a length F (FIG. 7)
which has been required from the front end of the front side
vehicle attaching portion 5 to the rear end of the rear side
vehicle body attaching portion 6 as in the conventional example,
even when a length E (FIG. 1) of the vehicle body attaching portion
52 is made comparatively short, a sufficient length of attaching
span can be ensured. Accordingly, a width of pivoting of the upper
arm 17 can be made narrower than that in the conventional
example.
[0051] Furthermore, the upper arm 17 is formed as an integrated
member constituting substantially a triangle shape and is provided
with sufficient rigidity even when the cross pipe 3 (FIG. 7) as in
the conventional case is omitted. Accordingly, the upper arm 17 can
be made small-sized and light-weight as a whole. Furthermore, the
upper arm 17 is constituted by the front pipe 50, the rear pipe 51
and the vehicle body attaching portion 52 in a pipe shape. The
upper arm 17 can be made further light-weight and inexpensive also
in this respect.
[0052] An explanation will now be given of a second embodiment of
the present invention. According to the second embodiment, only the
construction of the upper arm is changed. Other portions are not
changed and accordingly, an explanation thereof will be omitted.
FIG. 6 shows a plan view of the upper arm 17 according to the
second embodiment shown by notations common to those in the first
embodiment. As is apparent from the drawing, the upper arm 17 of
the second embodiment is constituted by substantially a triangular
shape in plan view similar to that in the previous embodiment;
however, an entirety thereof is integrally formed in one piece by
casting by using pertinent metal of an aluminum alloy.
[0053] At the center of the upper arm 17, there is provided a wall
through hole 85. At a surrounding portion thereof, a front portion
80, a rear portion 81 and a vehicle attaching portion 82 are
provided substantially in a triangular shape. An aggregated arm
portion 83 is provided at integrated front end sides of the front
portion 80 and rear portion 81, a cushion attaching portion 86 is
attached substantially at a central portion thereof and a ring
portion 84 for attaching a ball joint is provided at a front end
side thereof. An inner structure of the vehicle body attaching
portion 82 is similar to that in the previous embodiment and 88 in
the drawing designates a seal cap.
[0054] A relationship relative to the joint center line L is also
similar to that in the first embodiment. The attaching center B of
the cushion attaching portion 86 and a rear end portion 82a of the
vehicle body attaching portion 82 are respectively disposed forward
from the joint center line L, and a portion constituting a rear
edge portion of the rear portion 81 and proximate to the vehicle
body attaching portion 82, constitutes an escape portion 87
disposed frontward from the joint center line L. It is preferable
that the escape portion 87 is formed in a range of substantially
about a half or more of the rear portion 81.
[0055] When a total of the upper arm 17 is integrally formed in
this way, fabrication is further facilitated than the upper arm 17
integrated with pipes as in the first embodiment and the degree of
freedom with regard to shapes of respective portions such as the
shape of the escape portion 87 is enlarged. Furthermore,
particularly, when the upper arm 17 is cast by using an aluminum
alloy, an entirety thereof can be sufficiently small-sized and
light-weight.
[0056] Furthermore, the present invention is not limited to the
above-described respective embodiments but can be modified or
applied variously within the principle of the present invention.
For example, the escape portions 65 or 87 are not necessarily
needed and therefore may be abolished and the rear edge portion of
the rear pipe 51 or the rear portion 81 may overlap the joint
center line L.
[0057] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims.
* * * * *