Brakes – Internal-resistance motion retarder – Using a rotary-type fluid damper
Reexamination Certificate
2001-02-16
2003-05-13
Schwartz, Christopher P. (Department: 3683)
Brakes
Internal-resistance motion retarder
Using a rotary-type fluid damper
C188S290000
Reexamination Certificate
active
06561323
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary damper that is fitted to a pair of rotary members relatively pivotally combined together respectively via rotating support shafts.
2. Description of the Related Art
FIG. 6
shows an example of a conventional rotary damper for uses mentioned above. The conventional rotary damper
81
has a rotor
83
with an insert tube
87
extending from one side of an annular cap
86
, and a body case
82
formed with a tubular space
90
with one end blocked by a tubular wall. The cap
86
of the rotor
33
is formed with a mating projection
89
projecting from a side opposite to that one side with the insert tube
87
, and a collar
88
projecting from the outer peripheral face. A first O-ring groove
91
is formed on the side of an outer wall
97
and a second O-ring groove
92
is formed in the open end portion of the tubular space of the body case
82
. The outer wall
97
extends further along the axial direction from a the open end portion of the tubular space
90
, and its end portion forms an annular tubular portion
93
mating with the collar
88
of the cap
86
.
A first O-ring
84
is disposed in the first O-ring groove
91
, whereas a second O-ring
92
is disposed in the second O-ring groove
85
. The insert tube
87
of the rotor
83
is inserted into the tubular space
90
via a gap between these O-rings
84
and
85
. Further, the tubular space
90
is filled with a viscous substance such as silicone oil. A first gap
94
formed between the insert tube
87
and the inner wall
98
and sealed up with the second O-ring
85
and a second gap
95
formed between the insert tube
87
and the outer wall
97
and sealed up are replete with the viscous substance.
The rotor
83
is stopped from slipping off by the annular tube
93
mating with the collar
88
in such a condition that the body case
82
and the rotor
83
are joined together. The first O-ring
84
is pressed to contact, and contained in, the first O-ring groove
84
, whereas the second O-ring
85
is pressed to contact, and contained in, the second O-ring groove
92
. The central hole of the cap
86
and that of the body case
82
are coupled together and used to form an integral insert hole
96
.
Since the first and second gaps
94
and
95
in the conventional rotary damper
81
are replete with the viscous substance, resistance force is produced as the viscous substance is sheared when the body case
81
and the rotor
83
are relatively pivoted, so that the relative pivoting operations of the body case
82
and the rotor
83
are damped.
Consequently, by mixing the body case
82
to one of the pair of members combined together in such a manner capable of relatively pivoting, fixing the rotor
83
to the other member, and inserting these rotating support shafts into the insert hole
96
, the damping force with respect to the pair of members becomes obtainable.
In the above conventional rotary damper, the resistance force of the viscous substance for damping the pivoting operations relies upon areas where the outer and inner walls
97
and
98
are brought into contact with the viscous substance in a case where the characteristics of the viscous substance are the same. In the rotary damper above, however, it has been needed to increase the size of the rotary damper in order to increase the damping force because the contact surfaces above are mainly provided in the respective first and second gaps
94
and
95
.
Moreover, as the first and second O-rings
84
and
85
are situated in the same position in the axial direction, it is also needed to increase the outer diameter of the rotary damper
81
so as to secure the first and second O-ring grooves
91
and
92
. At the same time, the O-ring grooves
91
and
92
tend to be dislocated from the respective corresponding O-ring grooves
91
and
92
when the insert tube
87
is inserted into the tubular space
90
, thus causing the O-rings
84
and
85
to undergo a positional deviation. The problem is that such a positional deviation remains hardly visually confirmable.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotary damper which is compact and still capable of offering a greater damping force and is also readily incorporated in any vehicle.
In order to accomplish the object above, a rotary damper according to a first invention which is fitted up with a pair of rotary members in combination so that the pair of rotary members can relatively pivot via a rotary support shaft, comprises:
an outer tube which has a tubular space inside the wall of the outer tube and is so configured that one end of the space is closed; and an inner tube basically similar in shape to the outer tube but smaller in diameter than the outer tube, wherein
the outer wall of the inner tube is fitted into the tubular space of the outer tube;
the inner wall of the outer tube is fitted into the tubular space of the inner tube;
O-rings are respectively installed in an end portion on the open side of the gap between an inner portion of the outer wall of the outer tube and an outer portion of the outer wall of the inner tube, and in an end portion on the open side of the gap between an inner portion of the inner wall of the outer tube and an outer portion of the inner wall of the inner tube;
the gaps between the inner tube and the cuter tube sealed by these O-rings are filled with a viscous substance;
the central hole of the inner tube is a through-hole for receiving the rotating support shaft; and
mating means mating with the respective rotating members are provided to the inner tube and the outer tube.
As the first invention is so configured that the tubular spaces are formed respectively in the inner and outer tubes; the outer wall of the inner tube is fitted into the tubular space of the outer tube; and the inner wall of the outer tube is fitted into the tubular space of the inner tube, the first gap is formed between the inner wall of the inner tube and the inner wall of the outer tube; the second gap, between the inner wall of the outer tube and the outer wall of the inner tube; and the third gap, between the outer wall of the inner tube and the outer wall of the outer tube. Consequently, the three-layer gap is formed between the inner and outer tubes and directed outward from the center along the diametrical direction. In comparison with the conventional rotary damper with the two-layer gap formed and directed outward from the center along the diametrical direction, a greater area in contact with the viscous substance filled in the gaps is achievable even though the prior art rotary damper and what embodies the invention are of a size. Therefore, it is possible to provide a rotary damper which is more compact and capable of offering a greater damping force than the conventional rotary damper.
The O-rings are respectively installed in the end portion on the open side of the gap between an inner portion of the outer wall of the outer tube and an outer portion of the outer wall of the inner tube, and in the end portion on the open side of the gap between an inner portion of the inner wall of the outer tube and an outer portion of the inner wall of the inner tube, whereby the O-rings are disposed in positions deviating from each other in the axial direction. Consequently, the diameter of the rotary damper according to the invention can be made smaller than the conventional rotary damper wherein such O-rings are disposed axially in the same position.
A second invention is such that the rotary damper according to the first invention includes an O-ring groove formed in the inner periphery on the open side of the gap between an inner portion of the inner wall of the outer tube and an inner portion of the inner wall of the inner tube, and an annular cap for closing the O-ring groove.
According to the second invention, a first O-ring is installed between the inner tube and the outer tube when the inner tube is inserted into the outer tube and after the inner tube is inserted in
McGinn & Gibb PLLC
Piolax Inc.
Schwartz Christopher P.
LandOfFree
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