U.S. patent application number 09/725104 was filed with the patent office on 2001-05-10 for vehicle having damping force generating mechanism.
This patent application is currently assigned to Honda Giken Kogyo Kabushiki Kaisha. Invention is credited to Makino, Hiroki, Tomizawa, Tsutomu.
Application Number | 20010000936 09/725104 |
Document ID | / |
Family ID | 26405822 |
Filed Date | 2001-05-10 |
United States Patent
Application |
20010000936 |
Kind Code |
A1 |
Makino, Hiroki ; et
al. |
May 10, 2001 |
Vehicle having damping force generating mechanism
Abstract
An inexpensive damping force generating mechanism capable of
generating both a compression side damping force and a tensile side
damping force has a simple, lightweight structure. The damping
force generating mechanism provides an inexpensive axle suspension
capable of simplifying the suspension structure, reducing the
weight, and effectively utilizing space. The damping force
generating mechanism includes an elastic body which generates a
damping force when being pressed. An internal pressure generating
member is inserted in the elastic body and resists the pressing
force.
Inventors: |
Makino, Hiroki; (Saitama,
JP) ; Tomizawa, Tsutomu; (Saitama, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
8110 GATEHOUSE ROAD
SUITE 500 EAST
FALLS CHURCH
VA
22042
US
|
Assignee: |
Honda Giken Kogyo Kabushiki
Kaisha
|
Family ID: |
26405822 |
Appl. No.: |
09/725104 |
Filed: |
November 29, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09725104 |
Nov 29, 2000 |
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09040476 |
Mar 18, 1998 |
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6186526 |
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Current U.S.
Class: |
280/124.1 |
Current CPC
Class: |
F16F 1/445 20130101;
F16F 1/377 20130101; F16F 3/12 20130101; F16F 2232/02 20130101;
B62K 25/16 20130101 |
Class at
Publication: |
280/124.1 |
International
Class: |
B60G 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 1997 |
JP |
HEI-9-064714 |
Mar 18, 1997 |
JP |
HEI-9-064715 |
Claims
What is claimed is:
1. A damping force generating mechanism comprising: an elastic body
which generates a damping force when compressed by a pressing
force; and an internal pressure generating member located within
said elastic body which generates a pressure opposed to the
pressing force.
2. The damping force generating mechanism according to claim 1,
wherein said internal pressure generating member comprises a spring
member.
3. The damping force generating mechanism according to claim 1,
wherein said internal pressure generating member comprises a
partitioned chamber containing a compressive gas or liquid.
4. The damping force generating mechanism according to claim 1,
wherein said internal pressure generating member comprises an
organic material having an elasticity.
5. The damping force generating mechanism according to claim 4,
wherein said organic material has a hollow portion.
6. The damping force generating mechanism according to claim 5,
wherein said organic material comprises a polyester-urethane based
material.
7. The damping force generating mechanism according to claim 4,
wherein said organic material comprises a polyester-urethane based
material.
8. A damping force generating mechanism comprising: an elastic body
which generates a damping force when compressed by a pressing force
in a pressing direction; and a restricting wall for suppressing
expansion of said elastic body in a direction perpendicular to the
pressing direction of said elastic body.
9. The damping force generating mechanism according to claim 8,
wherein said elastic body is separated from said restricting wall
with a gap located therebetween at a beginning of pressing of said
elastic body, and said elastic body is brought into contact with
said restricting wall with progressive pressing of said elastic
body.
10. The damping force generating mechanism according to claim 9,
wherein a contact area of said elastic body with said restricting
wall is enlarged with progressive pressing of said elastic
body.
11. The damping force generating mechanism according to claim 10,
wherein said elastic body has a hollow portion with an opening
opened toward said restricting wall, and an intermediate elastic
body is located within said hollow portion, whereby when said
elastic body is pressed, said intermediate elastic body is
compressed, being swelled out of the opening of said hollow
portion, and is brought into pressing contact with said restricting
wall.
12. The damping force generating mechanism according to claim 9,
wherein said elastic body has a hollow portion with an opening
opened toward said restricting wall, and an intermediate elastic
body is located within said hollow portion, whereby when said
elastic body is pressed, said intermediate elastic body is
compressed, being swelled out of the opening of said hollow
portion, and is brought into pressing contact with said restricting
wall.
13. The damping force generating mechanism according to claim 8,
wherein said elastic body has a hollow portion with an opening
opened toward said restricting wall, and an intermediate elastic
body is located within said hollow portion, whereby when said
elastic body is pressed, said intermediate elastic body is
compressed, being swelled out of the opening of said hollow
portion, and is brought into pressing contact with said restricting
wall.
14. A damping force generating mechanism comprising: an elastic
body which generates a damping force when being pressed in a
pressing direction; a hollow portion located within said elastic
body, with an opening opened in the direction perpendicular to the
pressing direction; an intermediate elastic body located in said
hollow portion; and a restricting wall provided opposite to the
opening of said hollow portion; wherein when said elastic body is
pressed, said intermediate elastic body is compressed, being
swelled out of the opening of said hollow portion, and is brought
into pressing contact with said restricting wall.
15. A vehicle comprising: a body having a front end and a rear end;
at least one rear wheel located at said rear end; a front frame
member having a rocking arm pivotally attached thereto, said
rocking arm having a wheel support member and a lever arm angularly
displaced from one another; at least one front wheel rotatably
attached to said wheel support member of said rocking arm; a
suspension arrangement operatively arranged between said front
frame member and said lever arm of said rocking arm, said
suspension arrangement including a damping force generating
mechanism having an elastic body which generates a damping force
when compressed by a pressing force applied thereto.
16. The vehicle according to claim 15, wherein said damping force
generating mechanism includes an internal pressure generating
member located within said elastic body which generates a pressure
opposed to the pressing force.
17. The vehicle according to claim 16, wherein said internal
pressure generating member comprises a spring member.
18. The vehicle according to claim 16, wherein said internal
pressure generating member comprises a partitioned chamber
containing a compressive gas or liquid.
19. The vehicle according to claim 16, wherein said internal
pressure generating member comprises an organic material having an
elasticity.
20. The vehicle according to claim 15, wherein said damping force
generating mechanism further comprises a restricting wall for
suppressing expansion of said elastic body in a direction
perpendicular to the pressing direction of said elastic body, and
wherein said elastic body has a hollow portion with an opening
opened toward said restricting wall, and an intermediate elastic
body is located within said hollow portion, whereby when said
elastic body is pressed, said intermediate elastic body is
compressed, being swelled out of the opening of said hollow
portion, and is brought into pressing contact with said restricting
wall.
Description
BACKGROUND OF THE INVENTION
1. 1. Field of the Invention
2. The present invention relates to a damping force generating
mechanism for generating a damping force by pressing an elastic
body.
3. 2. Description of the Background Art
4. A damping force generating mechanism is used for various
portions required for absorbing vibration, for example, used for a
so-called bottom link type suspension of a motorcycle in which a
front wheel is suspended from lower end portions of a front fork
through links. A general example of such a bottom link type
suspension is shown in FIG. 16 (see Japanese Patent Laid-open No.
Sho 62-187608).
5. Referring to FIG. 16, there is shown a scooter type motorcycle
01. A steering shaft 03 is turnably fitted in a head pipe 02. A
pair of right and left front forked portions 04 are integrally
mounted on the lower end of the steering shaft 03. A front wheel 06
is suspended from the lower ends of the front forked portions 04
through rocking arms 05 as link members.
6. With respect to the rocking arm 05, the base end thereof is
pivotably supported on the lower end portion of the front forked
portion 04, and the free end portion thereof rotatably supports the
front wheel 06. A suspension spring 07 is interposed between the
upper portion of the front forked portion 04 and an approximately
central portion of the rocking arm 05.
7. A shock load applied to the front wheel from irregularities on
the ground is damped by the suspension springs 07. However, when a
shock load is applied with an abrupt shock load, the suspension
springs are largely rebounded after being contracted once.
8. In an example described in Japanese Patent Publication No. Sho
57-49432, as shown in FIG. 17, a front end of a link 012 is
pivotably supported on the lower end portion of a front forked
portion 011 containing a hydraulic damping mechanism. A front wheel
013 is rotatably supported on a central portion of the link 012. A
subcushion unit 14 is interposed between the rear end of the link
012 and the central portion of the front forked portion 011.
9. The subcushion unit 014 includes a cylindrical main body 015
pivotably mounted on the front forked portion 011. A piston 016 is
slidably inserted in the cylindrical main body 015 and is connected
to a leading end of a rod 017 pivotably mounted on the link 012. A
cushion rubber 018 utilized as a damping member is inserted in the
cylindrical main body 015 in such a manner as to be mounted on the
upper surface of the piston 016. A stopper rubber 019 utilized as a
stopper member is inserted in the cylindrical main body 015 in such
a manner as to be mounted on the lower surface of the piston
016.
10. The subcushion unit 014 thus generates a compression side
damping force by the cushion rubber 018, and also generates a
tensile side damping force by the stopper rubber 019. Consequently,
the subcushion unit 014 can suppress both the bound and rebound of
the front wheel 013.
11. The above subcushion unit 014, however, has a disadvantage.
Since the piston 016 is slid in the cylindrical main body 015, and
the cushion rubber 018 and the stopper rubber 019 are separately
provided on the upper and lower surfaces of the piston 016, the
mechanism is complicated in structure, being heavy and
expensive.
SUMMARY OF THE INVENTION
12. In view of the foregoing, an object of the present invention is
to provide an inexpensive damping, force generating mechanism
capable of generating both a compression side damping force and a
tensile side damping force with a simple, lightweight
structure.
13. To achieve the above object, a damping force generating
mechanism is provided including an elastic body which generates a
damping force when being pressed, and an internal pressure
generating member inserted in the elastic body which resists the
pressing force.
14. With this configuration, the mechanism enables a large
displacement due to bending deformation of the elastic body and
thereby it enables absorption of a sufficient energy. The creep
generated upon bending deformation of the elastic body can be
reduced by repulsion of the internal pressure generating member
inserted in the elastic body accompanied by compressed deformation
of the internal pressure generating member. Accordingly, a damping
force generating mechanism can be obtained which is capable of
reducing the characteristic change due to permanent set. The
restoring ability after release of a load is also excellent due to
repulsion of the internal pressure generating member.
15. The internal pressure generating member may comprise a spring
member. With this configuration, the creep of the elastic body is
reduced by repulsion of the spring member accompanied by the
compression thereof. Accordingly, it is possible to make the
characteristic change due to permanent set smaller and to enhance
the restoring ability.
16. The internal pressure generating member may comprise a
partitioned chamber containing a compressive gas or liquid. With
this configuration, the creep of the elastic member is reduced by
repulsion of a compressive gas or liquid compressed and deformed
together with the partitioned chamber. Accordingly, it is possible
to make the characteristic change due to permanent set smaller and
to enhance the restoring ability.
17. The internal pressure generating member may comprise an elastic
organic material. The internal pressure generating member, which is
made from the organic material, can be easily molded in a shape
most suitable for the application. The organic material may have a
hollow portion. With this configuration, when the organic material
is compressed, a specific repulsive force can be obtained by the
presence of the hollow portion. The organic material may be a
polyester-urethane based material. With this configuration, it is
possible to obtain a specific repulsive force by a large elasticity
of a polyester-urethane based material.
18. To further achieve the object of the invention, a damping force
generating mechanism is provided which includes an elastic body
which generates a damping force when being pressed, and a
restricting wall for suppressing expansion of the elastic body
generated in the direction perpendicular to the pressing direction
of the elastic body.
19. When the elastic body is pressed, the expansion of the elastic
body in the direction perpendicular to the pressing direction is
restricted by the restricting wall. As such, the force of the
elastic body applied to the restricting wall becomes larger and the
sliding resistance of the elastic body is increased. As a result, a
desirable relationship of load to displacement can be easily
obtained by the action of the sliding resistance of the elastic
body in addition to the elastic characteristic of the elastic
body.
20. The elastic body may be separated from the restricting wall
with a gap therebetween at the beginning of pressing of the elastic
body, and brought into contact with the restricting wall with
progressive pressing of the elastic body.
21. At the beginning of the pressing, since the elastic body is not
brought into contact with the restricting wall due to the gap
therebetween, the load is gradually increased with an increase in
displacement only by the elastic characteristic of the elastic
body. However, as the elastic body is pressed to a state where the
elastic body is in contact with the restricting wall, the load is
rapidly increased with an increase in displacement by a combination
of the sliding resistance of the elastic body and the elastic
characteristics of the elastic body. As a result, a desirable
relationship of the load to the displacement can be obtained.
22. The contact area of the elastic body with the restricting wall
may be enlarged with further progress of pressing of the elastic
body. With this configuration, after the pressed elastic body is
brought into contact with the restricting wall, the contact area of
the elastic body with the restricting wall is enlarged and thereby
the sliding resistance of the elastic body is increased. As a
result, a desirable smooth relationship of the increased load to
the increased displacement can be obtained.
23. The elastic body may have a hollow portion opened to the
restricting wall side, with an intermediate elastic body inserted
in the hollow portion. Therefore, when the elastic body is pressed,
the intermediate elastic body is compressed, being swelled out of
the opening of the hollow portion, and is brought in press-contact
with the restricting wall.
24. When the elastic body is pressed, sliding resistance is
generated due to the contact of the elastic body with the
restricting wall in addition to the elastic characteristics of the
elastic body, and also the sliding resistance of the intermediate
elastic body due to the pressing contact of the restricting wall
with the intermediate elastic body compressed and swelled from the
opening of the hollow portion. As a result, a desirable
relationship of the load to the displacement of the elastic body
can be easily obtained.
25. To further achieve the object of the invention, a damping force
generating mechanism is provided which includes an elastic body
which generates a damping force when being pressed, a hollow
portion opened in the elastic body in the direction perpendicular
to the pressing direction, an intermediate elastic body inserted in
the hollow portion, and a restricting wall provided opposite to the
opening of the hollow portion. Thus, when the elastic body is
pressed, the intermediate elastic body is compressed, being swelled
out of the opening of the hollow portion, and is brought into
pressing contact with the restricting wall.
26. At the beginning of the pressing of the elastic body, elastic
characteristics of the elastic body and the intermediate elastic
body are generated. However, as the pressing of the elastic body
proceeds, the intermediate elastic body is compressed, being
swelled out of the hollow portion of the elastic body, and is
brought into contact with the restricting wall. Thus, sliding
resistance of the intermediate elastic body is generated. As a
result, a desirable relationship of the load to the displacement of
the elastic body can be easily obtained.
27. 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
28. 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:
29. FIG. 1 is a side view of a scooter-type motorcycle including a
wheel suspension to which a damping force generating mechanism
according to a first embodiment is applied, with parts partially
omitted;
30. FIG. 2 is a side view of a front forked portion and the
vicinity thereof;
31. FIG. 3 is a sectional view of essential portions of the front
fork portion;
32. FIG. 4 is a sectional view taken on line IV-IV of FIG. 3;
33. FIG. 5 is an exploded view in perspective of a case, lid member
and locking piece;
34. FIG. 6 is a sectional view of an elastic rubber body;
35. FIG. 7 is a view seen in the direction shown by arrow VII of
FIG. 6;
36. FIG. 8 is a view seen in the direction shown by arrow VIII of
FIG. 6;
37. FIG. 9 is a view seen in the direction shown by arrow IX of
FIG. 6;
38. FIG. 10 is a graph showing an elastic characteristic of the
elastic rubber body;
39. FIG. 11 is a sectional view of essential portions of a front
forked portion according to a modification of the first
embodiment;
40. FIG. 12 is a view seen from in the direction shown by arrow XII
of FIG. 11, showing a locking portion of a lever with an elastic
rubber body;
41. FIG. 13 is a view showing another example of the locking
portion of the lever with the elastic rubber body shown in FIG.
12;
42. FIG. 14 is a sectional view of essential portions of a front
forked portion according to another modification of the first
embodiment;
43. FIG. 15 is a view seen from in the direction shown by arrow XV
of FIG. 14, showing a locking portion of a lever with an elastic
rubber body;
44. FIG. 16 is a view showing a motorcycle including a prior art
front wheel suspension;
45. FIG. 17 is a sectional view showing another prior art front
wheel suspension;
46. FIG. 18 is a side view of an elastic body containing a spring
member according to a second embodiment;
47. FIG. 19 is a top view of the elastic body shown in FIG. 18;
48. FIG. 20 is a sectional view showing a damping force generating
mechanism of a wheel suspension;
49. FIG. 21 is a sectional view showing the damping force
generating mechanism of FIG. 20, which is in a state different from
that in FIG. 20;
50. FIG. 22 is a graph showing an elastic characteristic of the
damping force generating mechanism shown in FIG. 20;
51. FIG. 23 is a graph showing a change in creep amount with an
elapsed time for the damping force generating mechanism shown in
FIG. 20;
52. FIG. 24 is a sectional view of essential portions of a wheel
suspension using a damping force generating mechanism according a
modification of the second embodiment;
53. FIG. 25 is a sectional view of the essential portions of the
damping force generating mechanism of FIG. 24, which is in a state
different from that shown in FIG. 24;
54. FIG. 26 is a view showing a damping force generating mechanism
of a wheel suspension according to a third embodiment;
55. FIG. 27 is a sectional view taken on line XXXVII-XXXVII of FIG.
26;
56. FIG. 28 is a sectional view showing the damping force
generating mechanism of the wheel suspension of FIG. 26, which is
in a state different from that in FIG. 26;
57. FIG. 29 is a sectional view taken on line XXIX-XXIX of FIG.
28;
58. FIG. 30 is a graph showing an elastic characteristic of the
damping force generating mechanism shown in FIG. 26;
59. FIG. 31 is a sectional view of essential portions of a wheel
suspension using a damping force generating mechanism according to
a modification of the third embodiment;
60. FIG. 32 is a transverse sectional view taken on line
XXXII-XXXII of FIG. 31;
61. FIG. 33 is a sectional view of the damping force generating
mechanism of FIG. 31, which is in a state different from that in
FIG. 31;
62. FIG. 34 is a sectional view of essential portions of a wheel
suspension using a damping force generating mechanism according to
another modification of the third embodiment; and
63. FIG. 35 is a sectional view of the damping force generating
mechanism of FIG. 34, which is in a state different from that in
FIG. 34.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
64. A damping force generating mechanism according to a first
embodiment is described with reference to FIGS. 1 to 10. FIG. 1 is
a side view of a scooter-type motorcycle 1 including a wheel
suspension to which a damping force generating mechanism in the
embodiment is applied, with parts partially omitted.
65. A low level floor 4 is formed between a front portion 2 and a
rear portion 3 of the body. A down frame 6 extends downwardly from
a head pipe 5 provided on the front portion 2 of the body, being
curved rearwardly from the lower end portion, and is integrated
with the floor 4.
66. A steering shaft 7 is turnably fitted to the head pipe 5. A
pair of right and left front forked portions 8 are integrally
mounted on the lower end of the steering shaft 7, and they extend
downwardly therefrom. A rocking arm 9 as a link member is pivotably
supported at the lower end of each front forked portion 8 by means
of a pivot arm bolt 11. A front wheel 13 is rotatably supported by
the free ends of the rocking arms 9 through a front axle 12.
67. The front forked portion 8 is U-shaped in cross section with a
front wall and both side walls. The right and left side walls at
the lower end portion of the front forked portion 8 have bolt
holes. A bush 14 provided in a base end pivot portion 9a of the
rocking arm 9 is fitted between both side walls of the front forked
portion 8 at a position corresponding to the bolt holes. The bush
14 is rotatably supported by a pivot arm bolt 11 passing through
the bush 14 and the bolt holes of the side walls of the front
forked portion 8. Each side of the base end pivot portion 9a of the
rocking arm 9 is formed in a cylindrical shape having an enlarged
diameter. A plate-like lever 10 is integrated with the outer
peripheral surface of the cylindrical side portion of the base end
pivot portion 9a and extends therefrom in the radial direction.
68. In a state in which the rocking arm 9 extends rearwardly from
the base end pivot portion 9a, the lever 10 extends obliquely,
upward at an angle of about 60 degrees relative to the rocking arm
9. That is, it extends between the front forked portion 8 and the
rocking arm 9.
69. A fan-shaped case 15 is fixedly inserted in the front fork
portion 8 at a position adjacent to the upper portion of the base
end pivot portion 9a of the rocking arm 9.
70. As shown in FIG. 5, the case 15 is formed into a box-like shape
having a fan-shaped side wall 15a, an outer peripheral wall 15b, a
front wall 15c and a rear wall 15d. A slot 15e is formed in the
side wall 15a along the front edge, and three circular holes 15f
are formed in upper and lower ends of the front wall 15c and in the
upper end of the rear wall 15d in such a manner as to pass
therethrough in the right and left direction, that is, in the width
direction.
71. As shown in FIG. 5, there is provided a plate-like lid member
16 opposed to the side wall 15a for blocking the opening of the
case 15. The lid member 16, which is formed into the same fan-shape
as that of the side wall 15a, has a slot 16e corresponding to the
slot 15e, and three circular holes 16f corresponding to the
circular holes 15f.
72. A locking piece 17 is locked in the slots 15e and 16e opposed
to each other. In a state in which the lid member 16 is fitted to
the ease 15, only the lower side of the case 15 is opened.
73. An elastic rubber body 20 is contained in the case 15 covered
with the lid member 16. The elastic rubber body 20 is formed into a
shape shown in FIGS. 6 to 9. That is, the elastic rubber body 20
has a fan-shaped cross section similar to but smaller than that of
the inner space of the case 15, and also has a large projection 20a
projecting from the rear surface of the fan-shaped cross section.
In addition, corners at upper and lower ends of the front side of
the fan-shaped cross section are slightly cut off.
74. A circular hole 20b and a large-sized irregular rectangular
hole 20c are formed fore and aft in the elastic rubber body 20
having the above contour in such a manner as to pass through the
elastic rubber body 20 in the width direction. Slots 20e and 20f
are also formed in the elastic rubber body 20. The slot 20e
(corresponding to the slot 15e of the above case 15) is disposed
between the circular hole 20b and the front surface of the elastic
rubber body 20 in such a manner as to extend in parallel to the
front surface. The slot 20f passes through a base portion of the
projection 20a in parallel to the rear surface of the elastic
rubber body 20.
75. The elastic rubber body 20 exhibits a hysteresis characteristic
of compression and tensile actions, and it has both elastic and
damper functions.
76. The elastic rubber body 20, case 15, and the like are assembled
as follows. The lever 10 integrated with the rocking arm 9 is made
to pass through the slot 20f formed in the base portion of the
projection 20a of the elastic rubber body 20, to be thus mounted in
the elastic rubber body 20. The case 15 covers the elastic rubber
body 20 from the left side, and the lid member 16 closes the case
15 from the right side. Thus, the lever 10 is in a state being
inserted in the case 15 through the lower opening of the case
15.
77. The locking piece 17 is made to pass through the slot 15e of
the case 15, the slot 20e of the elastic rubber body 20, and the
slot 16e of the lid member 16, and hence to be fitted in the slots
15e, 20e and 16e. Then, a screw 25 is threaded into the circular
hole 15f formed in the upper end portion of the rear wall 15d of
the case 15 and in the circular hole 16f of the lid member 16
corresponding to the circular hole 15f, to thus integrally fix the
case 15 to the lid member 16.
78. The case 15 covered with the lid member 20, which is mounted to
the lever 10 through the elastic rubber body 20, is inserted into
the recess on the back side of the front forked portion 8 to the
extent that the front wall 15c of the case 15 is brought into
contact with the bottom of the recess.
79. Each of the right and left side walls of the front fork portion
8 has circular holes at specific upper and lower positions along
the bottom. The circular holes 15f and 16f of the case 15 and the
lid member 16 are aligned with the above circular holes, and bolts
26 are made to pass through these circular holes and are attached
to nuts. Accordingly, the case 15 and the lid member 16 are
co-fastened to the front forked portion 8 with the bolts 26, to be
thus fixed thereto.
80. In the assembled state, the elastic rubber body 20 is disposed
in the case 15 as shown in FIGS. 3 and 4. That is, with respect to
the elastic rubber body 20, the front end portion is positioned in
a state being locked by the locking piece 17, the rear portion is
held by the lever 10 inserted in the slot 20f, and the projection
20a projecting rearward is allowed to be brought in contact with
the rear wall 15d of the case 15.
81. In this way, the front wheel suspension in this embodiment has
a very simple structure that the elastic rubber 20 is interposed
between the front forked portion 8 and the lever 10 in a state in
which the front portion thereof is locked by the locking piece 17
and the rear portion thereof is locked by the lever 10.
82. When the front wheel 13 is applied with a shock generated by
irregularities of the ground and the rocking arm 9 is rocked, the
positional states of the rocking arm 9 and the lever 10 integrated
with the rocking arm 9 are changed from states indicated by a solid
line of FIG. 3 to states indicated by a two-dot chain line. As a
result, the lever 10 compresses the elastic rubber body 20 in the
forward direction, that is, on the front forked portion 8 side, and
elastically deforms it, to thereby generates a compression side
damping force.
83. In this case, the elastic rubber body 20 has a progressive
elastic characteristic shown in FIG. 10 in which the increasing
ratio of a load to a displacement is large in a large displacement
region as compared with a small displacement region. Specifically,
in a small displacement region that only the irregular rectangular
hole 20c of the elastic rubber body 20 is deformed, a compressive
stress is moderately generated to the displacement, but in a large
displacement region that not only the irregular rectangular hole
20c but also the circular hole 20b are deformed, the compressive
stress is rapidly increased with the displacement.
84. On the other hand, when the rocking arm 9 and the lever 10 are
reversely rocked, the main body of the elastic rubber body 20
generates a tensile damping force, and simultaneously the
projection 20a is pressed and compressed by the rear wall 15d of
the case 15, thus acting as a rebound stopper.
85. Accordingly, while the front wheel suspension in this
embodiment has the simple structure in which the elastic rubber
body 20 is interposed between the front fork portion 8 and the
lever 10, it exhibits a desirable damping effect due to the
function of the elastic rubber body 20 generating both a
compression side damping force and a tensile side damping force
thereby effectively absorbing shock applied from the ground to the
front wheel 13.
86. In this way, the front wheel suspension in this embodiment does
not require a pivot for supporting the elastic rubber body 20, and
has no sliding portion for a piston or the like, so that it can
obtain a stable damping characteristic without the occurrence of
any sliding friction, thereby enhancing the durability with a
simple, lightweight, and inexpensive structure.
87. It is to be noted that it becomes possible to obtain various
other elastic characteristics of the elastic rubber body 20 by
changing the shapes of the circular hole 20b and the irregular
rectangular hole 20c of the elastic rubber body 20, and hence to
easily provide an elastic body most suitable for each kind of
vehicle.
88. Next, the structure of a front wheel suspension disposed at the
lower end portion of a front forked portion 40 according to a
modification of the first embodiment will be described with
reference to FIGS. 11 and 12. This modification has the same basic
structure as that of the first embodiment, except for slightly
changed shapes of the parts. A base end pivot portion 41a of a
rocking arm 41 is rockably supported, by means of a pivot arm bolt
42, at the lower end of the front forked portion 40. The rocking
arm 41 has a plate-like lever 43 extending from the base end pivot
arm portion 41a in the radial direction. A fan-shaped case 44
adjacent to the upper side of the base end pivot portion 41a of the
rocking arm 41 is fixedly fitted in the front forked portion
40.
89. An elastic rubber body 45, which has throughholes 45b and 45c
passing through the elastic rubber body 45 in the width direction,
is fitted in the case 44. A locking piece 46 passes through the
front portion of the elastic rubber body 45 and locks it. A lever
43 is inserted in a slot 45d formed in the rear portion of the
elastic rubber body 45, and a projection 45a projecting rearwardly
from the rear portion is allowed to be brought into contact with
the rear wall of the case 44.
90. The lever 43 has a swelled portion 43b, a stepped portion 43c,
and a flange portion 43d. As shown in FIG. 12, the swelled portion
43b is swelled right and left, that is, in the width direction on
the base end side from a locking portion 43a to be locked with the
elastic rubber body 45, and the stepped portion 43c is formed at
the boundary between the locking portion 43a and swelled portion
43b. The flange portion 43d projects upward from the leading end of
the lever 43, as shown in FIG. 11.
91. The lever 43 passes through the slot 45d of the elastic rubber
body 45, and the elastic rubber body 45 is locked with the locking
piece 43a. At the same time, the elastic rubber body 45 is held
between the stepped portion 43c and the flange portion 43d of the
lever 43. The sliding motion of the elastic rubber body 45 relative
to the lever 43 is thus restricted by the stepped portion 43c and
the flange portion 43d of the lever 43. This allows the elastic
rubber body 45 to effectively generate a damping force.
92. FIG. 13 shows another example of the lever. A lever 50 has a
fitting portion 50c on the base end side of a locking portion 50a
at the boundary between the locking portion 50a and a swelled
portion 50b, and also has on the leading end side a flange portion
50d projecting in the right and left direction. An elastic rubber
body 51 is held between the fitting portion 50c and the flange
portion 50d of the lever 50, so that the sliding motion of the
elastic rubber body 45 relative to the lever 43 is restricted.
93. Next, another modification of the first embodiment will be
described with reference to FIGS. 14 and 15. The modification,
which also concerns a front wheel suspension provided on the lower
end portion of a front forked portion 60, is substantially similar
to the above modification shown in FIGS. 11 and 12 in terms of
shapes of a rocking arm 61, a lever 63, a case 64, and an elastic
rubber body 65, but is different therefrom in terms of the
structure of restricting the sliding motion of the elastic rubber
body 65 relative to the lever 63.
94. A circular hole 63b is formed in a plate-like locking portion
63a of the lever 63, and a circular hole 65e corresponding to the
circular hole 63b is formed in the elastic rubber body 65. The
circular hole 65e is continuous to a slot 65d formed in a rear
projection 65a, and further to a recess formed in the opposed
portion, to the slot 65d, of the rear portion of the elastic rubber
body 65. A knock pin 66 is inserted in the circular hole 63b of the
lever 63 and the circular hole 65e of the elastic rubber body
65.
95. Accordingly, the sliding motion of the elastic rubber body 65
relative to the lever 63 is restricted by the knock pin 66, so that
the elastic rubber body 65 is allowed to effectively generate a
damping force. The lever 63, which has no flange portion at the
leading end thereof, is easily inserted in the slot 65d of the
elastic rubber body 65 upon assembly.
96. Although description has been made by example of the front
wheel suspension for a motorcycle in the above first embodiment and
modifications thereof, the present invention can be applied to a
rear wheel suspension, and used as a damper mechanism for a power
transmission of an engine and a damper mechanism for a cam chain
tensioner.
97. Hereinafter, a second embodiment of the present invention will
be described with reference to FIGS. 18 to 23. In the second
embodiment also concerning a front suspension mechanism as in the
first embodiment, parts corresponding to those in the first
embodiment are indicated by the same reference characters.
98. FIGS. 18 and 19 shows the second embodiment, in which four
holes having different shapes and passing through an elastic rubber
body 120i in the width direction are formed in the elastic rubber
body 120. The four holes, an elliptic hole 120b (corresponding to
the slot 15e of the case 15 in the previous embodiment), an
irregularly elliptic hole 120c, a developed fan-shaped hole 120d,
and a contracted fan-shaped hole 120e are arranged from the front
side in this order. Further, a through-slot 120f is formed in the
base portion of a projection 120a along the rear surface of the
elastic rubber body 120.
99. A metal spring member 121 as an internal pressure generating
member is inserted in the developed fan-shaped hole 120d. The
spring member 121 is composed of radially extending plate springs
arranged in a fan-shape corresponding to the internal space of the
developed fan-shaped hole 120d. The spring member 121 is made
repulsive against a compression side pressing force while
generating an internal pressure.
100. The elastic rubber body 120 is contained in a case 15 in a
state shown in FIG. 20. That is, with respect to the elastic rubber
body 120, the front end portion is locked and positioned by a
locking piece 17 passing through the front portion. A lever 10 is
inserted in the slot 120f, and a projection 120a projecting
rearwardly is brought into contact with a rear wall 15d of the case
15.
101. As described above, the front wheel suspension in this
embodiment has a simple structure in which the elastic rubber body
120 containing the spring member 121 is interposed between a front
forked portion 8 and the lever 10 in the state that the front
portion of the elastic rubber body 120 is locked with the locking
piece 17 and the rear portion of the elastic rubber body 120 is
locked with the lever 10.
102. When a front wheel 13 is applied with shock generated by
irregularities of the ground or a load upon braking and thereby the
rocking arm 9 is rocked, the rocking arm 9 and the lever 10
integrated with the rocking arm 9 are rocked from a state shown in
FIG. 20 to a state shown in FIG. 21. The lever 10 thus presses the
elastic rubber body 120 forward onto the front forked portion 8,
and it elastically deforms the elastic rubber body 120. As a
result, the spring member 121 inserted in the elastic rubber body
120 is compressed and is made repulsive while generating an
internal pressure.
103. In this case, the elastic rubber body 120 has an elastic
characteristic shown in FIG. 22, in which the displacement of the
elastic rubber body 120 is increased from the initial state having
an initial strain to a sufficiently large value by increasing the
applied load, and then the displacement is decreased along the
hysteresis curve by decreasing the load and finally it becomes zero
when the load reaches zero. Accordingly, the elastic rubber body
120 can ensure a large displacement and obtain sufficient energy
absorption, and further it improves the initial strain.
104. The result of an experiment of examining the generation amount
of creep of the elastic rubber body 120 containing the spring
member 121 is shown in FIG. 23. In FIG. 23, an example of using the
prior art elastic body not containing the spring member is shown by
a broken line, and the example using the elastic rubber body 120
containing the spring member 121 is shown by a solid line. As is
apparent from this figure, the creep amount of the elastic rubber
body 120 is significantly reduced as compared with the prior art
elastic body.
105. The characteristic change of the elastic rubber body 120 due
to fatigue is thus small. Further, the elastic rubber body 120 is
excellent in restoring ability after release of a load. That is,
while the prior art elastic body causes approximately 100% of the
permanent strain, the elastic rubber body 120 only causes
approximately 40% of the permanent strain.
106. A modification of the second embodiment will be described with
reference to FIGS. 24 and 25. The modification is the same as the
second embodiment, except for an elastic body 130 and an internal
pressure generating member 131 inserted in the elastic body 130. In
this modification, parts corresponding to those in the second
embodiment are indicated by the same characters.
107. The elastic body 130 is made from polyester elastomer and has
an outer shape being substantially the same as that of the elastic
body 120 in the second embodiment. Further, an elliptic hole 130b,
and an irregularly elliptic hole 130c formed in the elastic body
130, and a slot 130f passing through the elastic body 130 along the
base portion of a rear projection 130a are formed in the same
shapes as those of the corresponding ones in the second embodiment.
In this modification, however, the developed fan-shaped hole 120d
and the contracted fan-shaped hole 120e are omitted, and instead,
an irregular circular hole 130d is formed and an internal pressure
generating member 131 is inserted in the irregular circular hole
130d.
108. The internal pressure generating member 131 is made from
polyester-urethane being softer and more elastic than the elastic
body 130 and is formed in a cylindrical shape having a specific
wall thickness. When the elastic body 130 is applied with a load
and a rocking arm 9 is rocked, the rocking arm 9 and a lever 10
integrated with the rocking arm 9 are rocked from a state shown in
FIG. 24 to a state shown in FIG. 25, so that the lever 10 presses
the elastic body 130 forward to a front forked portion 8 and
thereby it elastically deforms the elastic body 130. In such a
state, the internal pressure generating member 131 inserted in the
elastic body 130 is compressed and is made repulsive while
generating an internal pressure.
109. The elastic body 130 can ensure a large displacement and
obtain a sufficient energy absorption, and it is significantly
reduced in creep by the effect of the internal pressure generating
member 131 and thereby it is small in characteristic change due to
fatigue. Further, the elastic body 130 is excellent in restoring
ability after release of a load.
110. In addition, the elastic body may be made from rubber in place
of polyester-urethane. Also, with respect to the internal pressure
generating member 131 made from polyester-urethane, the cylindrical
hollow type may be replaced with a solid type. And, a different
elastic substance may be inserted in the hollow portion of the
elastic body.
111. The internal pressure generating member may be made from an
organic material having a specific elasticity, in place of
polyester-urethane. In this case, the organic material can be
easily molded into a shape most effective to the application use of
the elastic body.
112. Additionally, it may be considered to form an enclosed
partition chamber containing a compressive gas or liquid in the
elastic body. When the elastic body is pressed and deformed, the
gas or liquid contained in the partition chamber is compressed to
generate an internal pressure. Such an elastic body is allowed to
be significantly reduced in creep and hence to be reduced in
characteristic change, and also to enhance the restoring ability
after release of a load.
113. A third embodiment of the present invention will be described
with reference to FIGS. 26 to 30. In the third embodiment also
concerning a front wheel suspension as in the previous embodiments,
parts corresponding to those in the previous embodiments are
indicated by the same characters. FIG. 27 shows the third
embodiment using an elastic body 220 made from polyester elastomer.
The elastic body 220 is formed in a shape being substantially
similar to but smaller than that of the inner space of the case 15.
The elastic body 220 has right and left side surfaces 220R and 220L
which are substantially parallel to each other and are slightly
curved in such a manner as to be gradually close to each other in
the direction from the front side to the rear side, and it has a
large projection 220a projecting from the rear portion thereof.
114. Three holes of different shapes are formed in the elastic
rubber body 220 having such a contour. These holes, an elliptic
hole 220b (corresponding to the elliptic hole 15e of the case 15 in
the previous embodiment), an irregular elliptic hole 220c, and an
irregular elliptic hole 220d are arranged from the front side in
this order. Further, a slot hole 220e is formed which passes
through the base portion of the projection 220a along the rear
surface of the elastic rubber body 220.
115. As shown in FIG. 27, the right and left side surfaces 220R and
220L of the elastic body 220 contained in the case 15 are
respectively brought into contact with a side wall 15a of the case
15 and a lid member 16 on the front side of the elastic body 220,
that is, on the side locked with a locking piece 17, and they are
gradually separated from the side wall 15a of the case 15 and the
lid member 16 with the increased gap as nearing the rear side. In
this way, the front wheel suspension in this embodiment has a
simple structure in which the elastic body 220 is interposed
between a front forked portion 8 and a lever 10 in such a manner
that the front portion thereof is locked with the locking piece 17
and the rear portion thereof is locked with the lever 10.
116. When a front wheel 13 is applied with a shock generated by
irregularities on the ground or a load upon braking and thereby the
rocking arm 9 is rocked, the rocking arm 9 and the lever 10
integrated with the rocking arm 9 are rocked as shown in FIGS. 28
and 29, so that the lever 10 presses the elastic body 220 forward
to the front forked portion 8 and thereby it elastically deforms
the elastic body 220.
117. When being pressed, the elastic body 220 is expanded in the
direction perpendicular to the pressing direction, that is, in the
vertical direction and also in the right and left direction. The
expansion of the elastic body 220 in the right and left direction
causes the right and left side surfaces 220R and 220L to be swelled
and to be respectively brought in contact with the side wall 15a of
the case 15 and the lid member 16. Consequently, the expansion of
the elastic body 220 is suppressed by the above contact, and as the
pressing of the elastic body 220 proceeds, the contact area thereof
is increased, so that the sliding resistance of the elastic body
220 at the contact surface of the right and left side surfaces 220R
and 220L with the side wall 15a of the case 15 and the lid member
16 is increased. Thus, as the displacement (stroke) of the elastic
body 220 is increased, the sliding resistance as well as the
elastic force of the elastic body 220 is progressively
increased.
118. The stroke-load characteristic in this embodiment is shown by
a solid line of FIG. 30. The stroke-load characteristic forms a
hysteresis curve. At the beginning of the motion of the elastic
body 220, that is, when the stroke is small, the sliding resistance
of the elastic body 220 is small and thereby the gradient of the
curve of the load to the stroke is moderate. When the stroke
becomes relatively large, the sliding resistance is added to the
elastic force, and thereby the gradient of the curve is increased.
When the stroke becomes very large, the gradient is further
increased by the action of the progressively increased sliding
resistance. In this way, the front wheel suspension in this
embodiment exhibits the desirable damping effect.
119. The action of the sliding resistance can be easily adjusted by
changing the shapes of the right and left side surfaces 220R and
220L of the elastic body 220, to thereby easily obtain a specific
stroke-load characteristic.
120. A modification of the third embodiment will be described with
reference to FIGS. 31 to 33. In the modification also concerning a
front wheel suspension as in the third embodiment, parts
corresponding to those in the third embodiment are indicated by the
same characters. An elastic body 230 is formed into the same shape
as that of the elastic body 220 in the third embodiment. However,
in the elastic body 230, an intermediate elastic body 235 is
inserted in an irregular elliptic hole 230C as one of hollow
portions. The intermediate elastic body 235 is made from a material
smaller in elastic modulus than the elastic body 230, that is,
deformable easier than the elastic body 230.
121. In a state before the rocking arm 9 is rocked (see FIGS. 31
and 32), as shown in FIG. 32, the intermediate elastic body 235 is
fitted in the irregular elliptic hole 230c, that is, not swelled
from the right and left openings of the irregular elliptic hole
230c.
122. When the front wheel 13 is applied to shock generated by
irregularities on the ground and the rocking arm 9 is rocked, the
elastic body 230 is pressed and elastically deformed, so that the
irregular elliptic hole 230c is also compressed in the pressing
direction and it compresses the intermediate elastic body 235
contained in the hole 230c. At this time, the intermediate elastic
body 235 made from a soft material is easily deformed, being
expanded in the direction perpendicular to the compression
direction, and is swelled from the right and left openings of the
irregular elliptic hole 230c to be brought in contact with the side
wall 15a of the case 15 and the lid member 16. The expansion of the
intermediate elastic body 235 is thus suppressed by the above
contact, and consequently the sliding resistance thereof at the
contact surface is increased.
123. As described above, right and left side surfaces 230R and 230L
of the elastic body 230 itself are brought in contact with the side
wall 15a of the case 15 and the lid member 16 respectively, so that
the sliding resistance of the elastic body 230 is increased. As a
result, the elastic forces of the elastic body 230 and the
intermediate elastic body 235 and the sliding resistance of the
elastic body 230 are further added with the sliding resistance of
the intermediate elastic body 235. The stroke-load characteristic
of the front wheel suspension having the above configuration is
shown by a broken line of FIG. 30.
124. In the stroke-load characteristic of this modification, the
gradient of the curve is rapidly raised in a early region with a
small stroke, as compared with the characteristic of the third
embodiment shown by the solid line. In this way, the front wheel
suspension in this modification is allowed to change the
stroke-load characteristic with a simple structure in which the
intermediate elastic body 235 is inserted and hence to easily
obtain a specific characteristic.
125. Another modification will be described with reference to FIGS.
34 and 35. This modification has the same basic structure as that
of the previous modification shown in FIGS. 31 to 33, except that
the shape of an elastic body 240 is slightly different from that of
the above-described elastic body 230. In this modification, parts
corresponding to those in the previous modification are indicated
by the same characters.
126. The elastic body 240 having right and left side surfaces 240R
and 240L parallel to each other is contained in the case 15 between
the side wall 15a and the lid member 16 with gaps therebetween. As
shown in FIG. 35, even when the elastic body 240 is pressed, the
right and left side surfaces 240R and 240L are not brought in
contact with the side wall 15a and the lid member 16 with gaps kept
therebetween. Accordingly, upon pressing of the elastic body 240,
the expansion thereof is not restricted, differently from the
elastic body 230 in the previous modification.
127. An intermediate elastic body 245 is inserted in an irregular
elliptic hole 240c of the elastic body 240, and as shown in FIG.
34, before the elastic body 240 is pressed, the intermediate
elastic body 245 is contained in the irregular elliptic hole 240c.
However, as shown in FIG. 35, when the elastic body 240 is pressed,
the intermediate elastic body 245 is compressed and expanded in the
direction perpendicular to the compression direction, being swelled
from the right and left openings of the irregular elliptic hole
240c, and is brought in contact with the side wall 15a of the case
15 and the lid member 16. The expansion of the intermediate elastic
body 245 is thus suppressed by the above contact, and thereby the
sliding resistance thereof at the contact surface is increased.
128. Accordingly, when the elastic body 240 is pressed, the elastic
force of the elastic body 240 is added with the sliding resistance
of the intermediate elastic body 245, so that there can be obtained
a stroke-load characteristic different from that in the previous
modification.
129. 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.
* * * * *