Rotary expansible chamber devices – Interengaging rotating members – Like rotary members
Reexamination Certificate
1998-02-03
2001-03-27
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Interengaging rotating members
Like rotary members
C418S206100
Reexamination Certificate
active
06206668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluid machine, for example, used for a supercharger of an automotive vehicle.
2. Description of the Related Arts
A Roots displacement compressor
201
as shown in
FIGS. 1 and 2
is described in Japanese Patent Unexamined Application Laid Open No. 2-91492.
The compressor
201
is provided with a compressor casing
203
, a pair of rotors
205
and
207
, an input pulley
209
and a timing gear set
211
.
Each of the rotors
205
and
207
is disposed within a rotor chamber
213
provided in the casing
203
and is rotated by a driving force of an engine input through the input pulley
209
. The timing gear set
211
rotates each of the rotors
205
and
207
to an opposite direction to each in a synchronous manner in order that each of the rotors
205
and
207
is not brought into contact with each other.
As shown in
FIG. 2
, a suction port
215
and a discharge port
217
for a fluid is provided at a position substantially perpendicular to an axial direction of each of the rotors
205
and
207
in the casing
203
.
The rotor chamber
213
is structured such that a horizontal cross section (a cross section in a direction perpendicular to the axis) is formed as a letter
8
shape by holes
219
and
221
corresponding to a rotating track of a front end of each of the rotors
205
and
207
, and convex portions
223
and
225
projecting to each of the rotors
205
and
207
are formed in a crossing portion of each of the holes
219
and
221
along the axial direction of each of the rotors
205
and
207
.
However, as shown in
FIG. 3
, in the casing
203
, the discharge port
217
end becomes a high temperature and is expanded, the suction port
215
end having a lower temperature than the discharge port end is compressed, and a heat moves to the low temperature end from the high temperature end as an arrow
227
. Due to an expansion, a compression and a heat movement generated in the above manner, the suction port
215
is displaced to an inner side as described by a broken line
229
and the discharge port
217
is displaced to an outer side, so that a distortion is generated in the casing
203
.
Further, since a suction air in the suction port
215
end has a pressure lower than that in the discharge port
217
end, each of the rotors
205
and
207
is displaced to the suction port
215
end by this pressure difference. The displacement is generated in such a manner that each of the rotors
205
and
207
swings around a bearing
231
or a bearing
233
.
Due to the distortion of the casing
203
and the displacement of each of the rotors
205
and
207
, the casing
203
and each of the rotors
205
and
207
are interfered with each other, so that an abrasion, a seizure, a poor motion of the compressor
201
and the like are generated.
Still further, since the convex portions
223
and
225
are formed in the casing
203
, there is a risk that the abrasion, the seizure, the poor motion and the like when the casing
203
and each of the rotors
205
and
207
are interfered with each other are promoted.
Furthermore, in the Roots displacement compressor
201
, there is a problem that a discharge of a fluid is intermittently performed and a back flow is generated in the discharge end so that a noise is increased.
SUMMARY OF THE INVENTION
The present invention has been achieved with such points in view.
It therefore is an object of the present invention to provide a fluid machine which prevents an interference between a casing and each of rotors or an abrasion, a seizure and the like when the casing and each of rotors are interfered with each other, thereby preventing the poor motion on the fluid machine.
To achieve the object, according to a first aspect of the present invention, there is provided a fluid machine comprising: a pair of rotors formed with a concave portion and a convex portion in such a manner as to extend to an axial direction, the pair of rotors meshed with each other at the concave portion and the convex portion; and a casing having a rotor chamber formed with a first pair of cylindrical portions enveloping each of the rotors, the casing having a flow inlet port and a flow outlet port for a fluid formed in the casing at a position substantially perpendicular to the axial direction of each of the rotors, the flow inlet port and the flow outlet port disposed inside two lines Y
1
and Y
2
which are perpendicular to a line X connecting centers of both of the cylindrical portions and pass through the center of each of the cylindrical portions, wherein the rotor chamber is formed with a second pair of cylindrical portions including a horizontal cross sectional shape which is constituted by a part of a circle corresponding to a second rotation track of each of the rotors, together with the first pair of cylindrical portions including a horizontal cross sectional shape which is constituted by a part of a circle corresponding to a first rotation track of each of the rotors; and the second pair of cylindrical portions are moved toward a lower pressure end among the flow inlet port and the flow outlet port from a position of the first pair of cylindrical portions at a predetermined distance L, thereby the volume of the rotor chamber is expanded.
As mentioned above, the second pair of cylindrical portions to envelop each of the rotors is moved or shifted from the position of the first pair of cylindrical portions at the predetermined distance L toward the lower pressure end among the flow inlet port and the flow outlet port. Accordingly, the rotor chamber is expanded at a degree corresponding to a volume increase due to the movement or the shifting of the second pair of cylindrical portions.
Accordingly, the interference between the casing and each of the rotors is prevented, and the abrasion and the seizure of these elements, the poor motion of the fluid machine and the like can be prevented.
According to a second aspect of the present invention, there is provided a fluid machine, comprising: a pair of rotors meshed with each other at a concave and convex portion formed in such a manner as to extend to an axial direction; and a casing enveloping each of the rotors in a pair of cylindrical portions provided in a rotor chamber in such a manner as to rotate and having a flow inlet port and a flow outlet port for a fluid, the flow inlet port and the flow outlet port are provided at a position substantially perpendicular to the axial direction of each of the rotors, wherein a horizontal cross sectional shape of each of the cylindrical portions is constituted by a part of a circle corresponding to a rotation track of each of the rotors; the flow inlet port and the flow outlet port are disposed inside two lines Y
1
and Y
2
which are perpendicular to a line X connecting centers of both of the cylindrical portions and pass through the center of each of the cylindrical portions; and positions of the cylindrical portions are moved to a moved center position from a standard center position at a predetermined distance L toward a lower pressure end among the flow inlet port and the flow outlet port, so as to expand the rotor chamber to a volume including each of the cylindrical portions at the moved center position together with each of the cylindrical portions at the standard center position.
As mentioned above, the cylindrical portion enveloping each of the rotors is moved to the moved center position from the standard center position at the predetermined distance L toward the lower pressure end among the flow inlet port and the flow outlet port. Accordingly, the rotor chamber is expanded at a degree corresponding to a volume increase due to the movement of each of the cylinder portions to the moved center position.
The higher pressure end among the flow inlet port and the flow outlet port becomes in a high temperature and the lower pressure end becomes in a low temperature, and an expansion and a compression is generated in the casing due to these temperature difference, so that, for e
Hiraishi Kenji
Teraoka Masao
Denion Thomas
Morrison & Foerster
Tochigi Fuji Sangyo Kabushiki Kaisha
Trieu Theresa
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