Expansible chamber devices – With guide or seal on cylinder end portion for piston or... – Non-metallic seal means between piston or member and end...
Reexamination Certificate
2000-07-10
2002-03-05
Look, Edward K. (Department: 3745)
Expansible chamber devices
With guide or seal on cylinder end portion for piston or...
Non-metallic seal means between piston or member and end...
Reexamination Certificate
active
06352019
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a diaphragm actuator which corresponds to a kind of hydraulic actuator.
2. Description of the Related Art
Conventionally, there has been known a diaphragm actuator in which a diaphragm
52
is linked in an inner portion of a cup
51
so as to form a pressure chamber
53
, a pressure is supplied to the pressure chamber
53
so as to actuate the diaphragm
52
and a rod
54
connected to the diaphragm
52
and the rod
54
is supported by a bearing
55
arranged in an inner side of the cup
51
, as shown in FIG.
4
. The bearing
55
is mounted to an inner peripheral surface of the cup
51
via a retainer
56
, and an outside diameter of the bearing
55
is set to be significantly smaller than an outside diameter of the retainer
56
integrally having a spring receiving portion
56
a
receiving a spring
57
for returning the diaphragm
52
. Further, the bearing
55
is structured such that an inside peripheral surface is formed in a cylindrical shape and an outer peripheral surface is formed in a barrel shape or a circular arc cross sectional shape in which an outside diameter is the largest in a center in an axial direction, so that when the rod
54
swings, the bearing
55
swings within the retainer
56
so as to follow the swing motion of the rod
54
.
However, there are the following disadvantages in the diaphragm actuator mentioned above.
That is, since a temperature in an atmosphere in a side of the rod
54
(in a vertically under side of the bracket
57
a
in the drawing) rises high when the diaphragm actuator is attached to an internal combustion engine or the like in a vehicle via a bracket
57
a,
a radiation heat is readily transmitted to an internal space
58
of the cup
51
via the metal bracket
57
a,
a lower surface portion
51
a
of the cup
51
and a spring receiving portion
56
a
of the retainer
56
, the internal space
58
becomes high in temperature and the diaphragm
52
is exposed to the high temperature. The diaphragm
52
is formed by a rubber-like elastic member having a relatively poor heat resistance. Accordingly, there is a risk that the diaphragm
52
is exposed to the high temperature and thermally deteriorated in shorter time.
Further, in addition, the diaphragm actuator has the following disadvantages.
That is, at first, since the exclusive retainer
56
is provided so as to hold the bearing
55
as mentioned above, the number of parts in the actuator is large. Further, since the bearing
55
is assembled in the retainer
56
at a time of assembling the actuator and an operation of assembling the retainer
56
in the cup
51
is required, an operation of assembling the actuator is complex and troublesome.
Still further, since the diaphragm
52
is structured such that an operating membrane portion
52
a
and a disc-like center portion
52
b
held between a diaphragm retainer
59
and a spring retainer
60
are formed in a uniform thickness, and is wholly formed so as to be thin. In addition, an upper end portion of the rod
54
is fixed to a laminated portion comprising the diaphragm
52
, the diaphragm retainer
59
and the spring retainer
60
by means of connecting means such as a spin caulking or the like. Accordingly, since a deformation range of a center portion
52
b
of the diaphragm
52
is set to be small in a manner so as to suitably apply a caulking load to the thin rubber-like elastic diaphragm
52
, it is necessary to severely control a magnitude of the caulking load so as to correspond to the caulking condition. Further, since it is a general practice that a pair of upper and lower washers
61
are added to the laminated portion so as to prevent only a caulked portion in the center portion
52
b
of the diaphragm
52
from being deformed due to the caulking load, there is a disadvantage that the number of parts in the actuator is further increased.
SUMMARY OF THE INVENTION
The present invention is made by taking the points mentioned above into consideration, and an object of the present invention is to provide a diaphragm actuator which is excellent in a heat insulation against a temperature in a peripheral atmosphere, thereby preventing a diaphragm from being thermally deteriorated, can decrease the number of parts in an actuator and can make it easy to assemble.
In order to achieve the object mentioned above, in accordance with the present invention, there is provided a diaphragm actuator in which a diaphragm is linked in an inner portion of a cup so as to form a pressure chamber, a pressure is supplied to the pressure chamber so as to actuate the diaphragm and a rod connected to the diaphragm and the rod is supported by a bearing arranged in an inner side of the cup, wherein the bearing is extended to an inner peripheral surface of the cup so as to be brought into contact with the inner peripheral surface, and a contact surface of the bearing with respect to the rod is formed in a circular arc cross-sectional shape having the smallest inside diameter in a center in an axial direction.
In the diaphragm actuator in accordance with the present invention having the structure mentioned above, since the bearing is extended to the inner peripheral surface of the cup and is brought into contact with the inner peripheral surface of the cup, a heat insulating layer against the temperature of the peripheral atmosphere is newly formed by the extended bearing. Since the bearing is made of resin and a heat conductivity of the resin is smaller than that of the metal that is a material of the retainer, it is possible to form a heat insulating layer which can achieve an excellent heat insulating effect.
Further, the bearing is also fixed to the inner side of the cup. Accordingly, the contact surface of the bearing with respect to the rod is formed in the circular arc cross-sectional shape having the smallest inside diameter in the center in the axial direction so as to support the rod in a swinging manner in spite of the fact that the bearing is fixed to the inner side of the cup, and in more detail, the inside diameter in the center in the axial direction is the smallest, the inside diameter is gradually expanded from the center in the axial direction toward both end portions in the axial direction and the cross sectional shape is formed in a smoothly circular arc curved surface.
Further, since the retainer in the prior art mentioned above can be omitted from the constituting elements of the actuator, it is possible to decrease the number of parts and improve an assembling operability.
REFERENCES:
patent: 63-53907 (1986-04-01), None
patent: 61-766 (1989-01-01), None
patent: 7-208407 (1995-08-01), None
Hasegawa Shinichi
Mizumachi Syoji
Jacobson & Holman PLLC
Leslie Michael
Look Edward K.
NOK Corporation
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