Brakes – Wheel – Transversely movable
Reexamination Certificate
2000-09-06
2001-09-25
Swann, J. J. (Department: 3611)
Brakes
Wheel
Transversely movable
C188S01800A, C188S074000, C188S078000, C277S361000, C277S365000, C277S399000, C277S402000
Reexamination Certificate
active
06293374
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drum brake seal structure for an all-terrain vehicle wheel, and more particularly to a drum brake designed to reliably provide a seal between a brake panel and a brake drum even when the brake drum is accidentally displaced from the brake panel.
2. Description of the Related Art
Drum brakes are well known in the art.
FIG. 3
hereof shows in cross-section one example of such drum brakes. A drum brake
100
includes a brake panel
101
, and a brake drum
105
rotationally mounted to an axle
103
by means of bearings
104
,
104
. The brake panel
101
has brake shoes
102
,
102
(only one shown) operably attached thereto. The brake shoes
102
,
102
are disposed to produce friction force in cooperation with the brake drum
105
. On an end portion
111
of the brake drum
105
, there is mounted a seal member
106
. The seal member
106
has lips
107
,
108
pressed against a surface of the brake panel
101
. A wheel cylinder
112
is provided for pressing the brake shoes
102
,
102
against an inner peripheral surface of the brake drum
105
. A wheel
114
is attached to the brake drum
105
by means of a bolt
113
and a nut
115
. Reference numerals
116
,
117
denote an oil seal and a knuckle, respectively.
The end portion
111
of the brake drum
105
is normally spaced from the surface of the brake panel
101
by a distance L
1
, as shown in (a) of FIG.
4
.
As an all-terrain vehicle employing the drum brake
100
travels, the axle
103
can be subjected to an external force.
If the axle
103
is undesirably bent by such an external force, the brake drum
105
may be displaced away from the brake panel
101
, as shown by an arrow in (b) of
FIG. 4
, to thereby provide a distance L
1
+&agr; between the brake drum
105
and the surface of the brake panel
101
.
As the brake drum
105
is displaced away from the brake panel
101
, the contact area of the lips
107
,
108
and the brake panel
101
becomes less. Thus, when the brake drum
105
is greatly displaced away from the brake panel
101
, as shown in (b) of
FIG. 4
, the seal member
106
can not reliably provide a seal between the brake drum
105
and the surface of the brake panel
101
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a drum brake seal structure for an all-terrain vehicle wheel, which is designed to reliably provide a seal between a brake panel and a brake drum even if the brake drum is accidentally displaced away from the brake panel.
According to an aspect of the present invention, there is provided a drum brake seal structure for an all-terrain vehicle wheel, comprising: a brake panel; a drum including a disc portion and a cylindrical portion extending from an outer peripheral end portion of the disc portion towards the brake panel; and a seal member mounted on an outer peripheral end portion of the cylindrical portion of the drum. The brake panel is disposed sidewardly of the cylindrical portion of the drum. The brake panel supports brake shoes disposed in such a manner as to be pressed against an inner peripheral surface of the cylindrical portion. The brake panel includes an annular flat surface portion and a cylindrical projecting portion projecting from an outer peripheral end portion of the annular flat surface portion in an axial direction of the drum so as to surround a radially outward side of the seal member. The seal member includes plural sealing lips which are in sealing contact with the brake panel. At least one of the sealing lips is in sealing contact with an inner circumferential surface of the cylindrical projecting portion.
Preferably, the plural lips comprise plural axial sealing lips extending in the same direction substantially parallel to the axis of the drum, and a radial sealing lip extending in a radial outward direction of the drum. The axial sealing lips are in sealing contact with the annular flat surface portion of the brake panel, and the radial sealing lip forms said at least one sealing lip and is in sealing contact with the inner circumferential surface of the cylindrical projecting portion.
Consequently, even if the drum is displaced in the same direction as the axle to thereby provide an increased distance between the brake panel and the drum, the radial sealing lip remains sealingly in contact with the inner peripheral surface of the projecting portion of the brake panel, thus providing a hermetic seal between the brake panel and the drum.
Moreover, while the wheel of the all-terrain vehicle is rotating, the outer lip is subjected to a centrifugal force produced by the rotation. Because of the radial sealing lip extending in a radially outward direction of the drum (i.e., in the direction in which the centrifugal force acts), the radial lip is forced against the inner peripheral surface of the projecting portion of the brake panel under the action of the centrifugal force.
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patent: 4283063 (1981-08-01), Prescott
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patent: 4534440 (1985-08-01), Sekizaki
patent: 4627520 (1986-12-01), Matsubayashi
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patent: 5011301 (1991-04-01), Martinie
patent: 5147139 (1992-09-01), Lederman
patent: 5522600 (1996-06-01), Duckwall
patent: 5553870 (1996-09-01), Czekansky
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patent: 359047530 (1984-03-01), None
Handa Akio
Katabami Eiji
Kurimoto Seiji
Seki Bunzo
Tomita Hiroaki
Divine David
Honda Giken Kogyo Kabushiki Kaisha
Merchant & Gould P.C.
Swann J. J.
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