Information
-
Patent Grant
-
6206668
-
Patent Number
6,206,668
-
Date Filed
Tuesday, February 3, 199826 years ago
-
Date Issued
Tuesday, March 27, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Trieu; Theresa
Agents
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
A fluid machine comprises a rotor (7, 9) meshed with each other in concave and convex portions (23, 26) and (25, 24), and a casing (3) enveloping these elements within cylindrical portions (43, 45) of a rotor chamber (5) and having a flow inlet port (31) and a flow outlet port (33). The cylindrical portions (43, 45) are moved to moved centers (47, 49) from standard centers (35, 37) at a predetermined distance L toward the flow inlet port (31), so that the rotor chambers (5) is expanded to cylindrical portions (55, 57) from the cylindrical portions (43, 45).
Description
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 example, even when the flow inlet port is displaced to the inner side and further even when each of the rotors is displaced to the flow inlet port end due to the pressure difference between the flow inlet port and the flow outlet port, the distortion of the casing and the displacement of each of the rotors mentioned above are absorbed by making each of the cylinder portions move to the moved center position toward the lower pressure end and expanding the rotor chamber.
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 third aspect of the present invention, as it depends from the first or the second aspect, when components in respective directions of a line X, a line Y
1
and a line Y
2
in the predetermined distance L are set to be respectively x
1
, y
1
and y
2
, a relation 0.05 (mm)≦x, y
1
, y
2
≦0.3 (mm) is made.
The structure discloses an optimum range of the distance L (x, y
1
, y
2
) at which the center of each of the cylindrical portion is moved, and the cylindrical portion is moved at the optimum moving distance L selected within the range. Accordingly, the interference between the casing and each of the rotors can be prevented in the manner mentioned above without affecting the performance of the fluid machine.
According to a fourth aspect of the present invention, as it depends from the first, the second or the third aspect, each of the rotors is rotated by a prime mover, the fluid is sucked from the flow inlet port of the casing and is discharged from the flow outlet port, and the center of each of the cylindrical portion is moved to the flow inlet port end at the predetermined distance L.
The fourth aspect corresponds to a structure in which the fluid machine is set to be a compressor, and the center of each of the cylindrical portion is moved to the flow inlet port end of the lower pressure end (the lower temperature end) at the predetermined distance L. Accordingly, the interference between the casing and each of the rotors can be prevented in the manner mentioned above.
According to a fifth aspect of the present invention, as it depends from one aspect among the first aspect to the fourth aspect, each of the cylindrical portions are crossed to each other so as to form a round portion having a predetermined radius r on one or both of a convex portion formed in the flow inlet port end and the flow outlet port end.
As mentioned above, the round portion having a predetermined radius r is given to the one or the both of the convex portion formed in such a manner as to project to the rotor end by each of the cylindrical portions crossing to each other in the flow inlet port end and the flow outlet port end.
As in the same manner as that of the first and the second aspect, even when the casing and each of the rotors are interfered with each other by the expansion and compression of the casing due to the temperature difference between the flow inlet port end and the flow outlet port end and by the displacement of each of the rotors due to the pressure difference in the flow inlet port end and the flow outlet port end, the abrasion and the seizure of each of the rotors and the casing can be prevented and the poor motion in the fluid machine can be prevented by the round portion given in the convex portion of the casing.
Further, as mentioned above, even when the casing and each of the rotors are interfered with each other due to the temperature difference and the pressure difference between the flow inlet port end and the flow outlet port end, the abrasion and the seizure of each of the rotors and the casing can be prevented and the poor motion in the fluid machine can be prevented by the round portion given in the one or the both of the convex portions formed in the flow inlet port end and the flow outlet port end of the casing.
According to a sixth aspect of the present invention, as it depends from one aspect among the first aspect to the fifth aspect, when a radius of a circle corresponding to a rotating track of each of the rotors is set to be R, a relation {fraction (1/10)}R (mm)≦r≦⅕R (mm) is made.
The structure discloses an optimum range of the radius r of the round portion given to the convex portion of the casing, and when the radius of the circle corresponding to the rotating track of each of the rotors is set to be R, the value of r is set to be within the above range with respect to the value of R. Accordingly, the abrasion, the seizure, the poor motion and the like occurred when the casing and each of the rotors are interfered with each other can be prevented without affecting the performance of the fluid machine.
According to a seventh aspect of the present invention, as it depends from one aspect among the first aspect to the sixth aspect, the predetermined radius r is set to be a different value along an axial direction of each of the rotors.
Since the radius r of the convex portion is changed in the axial direction of each of the rotors in accordance with the deformation amount of the casing different along the axial direction of each of the rotors and the displacement amount of each of the rotors and the optimum radius r is given at each of the portions, the abrasion and the seizure between the convex portion and each of the rotors and the poor motion of the fluid machine can be prevented all around the area in the most effective manner.
In other wards, since the deformation amount of the casing is different along the axial direction of each of the rotors, the abrasion and the seizure with respect to each of the rotors can be prevented all around the area of the convex portion in the most effective manner by giving the optimum radius r to each portion of the convex portion along the axial direction of the rotor, so that the poor motion of the fluid machine can be prevented.
Further, the displacement of each of the rotors due to the pressure difference between the flow inlet port and the flow outlet port is produced in such a manner that each of the rotors swings around the bearing in the above manner. The structure changing the value of the radius r along the axial direction of each of the rotors corresponds to the displacement amount of each of the rotors different in the axial direction, so that the abrasion and the seizure between the casing and each of the rotors, and the poor motion of the fluid machine can be effectively prevented.
According to a eighth aspect of the present invention, as it depends from one aspect among the first aspect to the seventh aspect, each of the rotors is rotated by a prime mover; a fluid is sucked from the flow inlet port of the casing and is discharged from the flow outlet port; and a round portion having a predetermined radius r is given to one or both of the convex portions in the flow inlet port and the flow outlet port.
In addition to the above matter, the eighth aspect corresponds to a structure in which the fluid machine is set to be a compressor, and the round portion having a predetermined radius r is given to the convex portion of the casing in one or both of the flow inlet port (the suction port) and the flow outlet port (the discharge port). Accordingly, the abrasion, the seizure and the poor motion in the fluid machine due to the interference between the casing and each of the rotors as mentioned above can be prevented.
Further, when the round portion is given to the convex portion near the discharge port, a gap is formed between the casing and each of the rotors due to the round portion. The flow speed change for the fluid can be reduced so that the sound is widely reduced. The structure is particularly advantageous for the fluid machine, namely the compressor according to this aspect with the lower sound level in the discharge end even though the sound level in the discharge end of the conventional compressors is high.
Further, when the round portion is given to the convex portion close to the suction port, the gap is formed between the casing and each of the rotors by this round portion, so that the interference between the casing and each of the rotors can be prevented by this gap. Accordingly, the interference between the casing and each of the rotors, the abrasion therebetween, the seizure, the poor motion in the fluid machine and the like can be prevented.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read in conjunction with the accompanying drawings, in which:
FIG. 1
is a cross section of a front view in accordance with a conventional embodiment;
FIG. 2
is a cross sectional view taken along the lines II—II in
FIG. 1
;
FIG. 3
is a cross sectional view of the casing shown in
FIG. 1
, showing a distortion state in the casing.
FIG. 4
is a cross section of a front view in accordance with a first and a second embodiments according to the present invention;
FIG. 5
is a cross sectional view taken along the lines V—V in
FIG. 4
which shows the first embodiment in accordance with the present invention;
FIG. 6
is a cross sectional view which shows the second embodiment in accordance with the present invention by modifying a portion of the rotor chamber shown in FIG.
5
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There will be detailed below the preferred embodiments of the present invention with reference to the accompanying drawings. Like members are designated by like reference characters.
A first embodiment in accordance with the present invention will described below with respect to FIG.
5
. This embodiment is provided with the features stated in the first, second third and fourth aspects.
FIG. 5
shows a Roots displacement compressor
1
as a fluid machine in accordance with the embodiment, and the compressor
1
is used for a supercharger of an automotive vehicle.
The supercharger is constituted by an input pulley
71
, a timing gear set
73
and
75
, a Roots displacement compressor
1
and the like.
As shown in
FIG. 5
, the compressor
1
is provided with a compressor casing
3
and a pair of rotors
7
and
9
disposed within a rotor chamber
5
provided in the casing
3
.
The rotors
7
and
9
are respectively constituted by rotor bodies
11
and
13
, rotor shafts
19
and
21
fixed to axial holes
15
and
17
thereof, and the like. In the respective rotor bodies
11
and
13
, two convex portions
23
and
25
formed in such a manner as to extend to an axial direction are rotated to the reverse direction while being meshed with opposite concave portions
26
and
24
.
The rotor bodies
11
and
13
of the rotors
7
and
9
are rotated and meshed with each other to keep a clearance between the rotor bodies
11
and
13
during the rotors
7
and
9
are driven and rotated through the timing gear set
73
and
75
. Therefore, the rotor bodies
11
and
13
are rotated and meshed with each other without contact, to keep the clearance. In other wards, respective connections between the rotor body
11
of the rotor
7
and the timing gear
73
and between the rotor body
13
of the rotor
9
and the timing gear
75
are designed so that the rotor bodies
11
and
13
are rotated and meshed with each other without contact when the timing gear set
73
and
75
are contactingly meshed with each other.
The respective rotors
7
and
9
reduce an inertia moment by providing hollow portions
27
and
29
each having a circular cross section in the respective convex portions
23
and
25
, thereby improving a response of the supercharger at a time of an acceleration and the like.
A suction port
31
as a flow inlet port and a discharge port
33
as a flow outlet port are provided at a position substantially perpendicular to an axial direction of the rotor shafts
19
and
21
in the casing
3
. A taper is attached to the suction port
31
and the discharge port
33
in such a manner that a flow passage area becomes wide toward the outer side as shown in FIG.
5
.
The input pulley
71
is connected to the input end rotor shaft
19
by a spline, and is connected to a crank shaft end pulley through a belt. An electromagnetic clutch is assembled to the crank shaft end pulley, so that the input pulley
71
is rotated through the electromagnetic clutch by a drive force of an engine.
A timing gear set
73
and
75
are constituted by a pair of timing gears meshed with each other, and the timing gears
73
and
75
are respectively connected to the rotor shaft
19
and
21
.
The compressor
1
is rotated by the drive force of the engine input from the input pulley
71
. At this time, the timing gear set
73
and
75
synchronously rotate the rotors
7
and
9
to the reverse direction in such a manner that the rotors
7
and
9
are not brought into contact with each other. The driven compressor
1
sucks an intake air from the suction port
31
by a rotation of the rotors
7
and
9
and discharges the air from the discharge port
33
so as to supercharge the engine.
The casing
3
is structured such that a cover
77
is fixed to an opening portion disposed on a side in an axial direction of a casing body
76
by bolts
79
and locate pins
81
, and the rotor chamber
5
is provided between the casing body and the cover. Furthermore, the rotor shafts
19
and
21
are rotatably mounted to the casing body
76
and the cover
77
through bearing members
83
and
85
, respectively.
The rotor chamber
5
is formed by combining a pair of cylindrical portions
43
and
45
(having a radius R) which respectively have rotating centers
35
and
37
in a standard position of the rotors
7
and
9
and correspond to rotating tracks
39
and
41
of the convex portions
23
and
25
and a pair of cylindrical portions
55
and
57
(having a radius R) which respectively have moved rotating centers
47
and
49
a predetermined distance L moved from the standard rotating centers
35
and
37
and correspond to rotating tracks
51
and
53
of the convex portions
23
and
25
.
Further, when a line connecting between the standard rotating centers
35
and
37
is set to be X and lines perpendicular to the line X and passing through the respective standard rotating centers
35
and
37
are set to be Y
1
and Y
2
, the suction port
31
and the discharge port
33
are disposed inside these two lines Y
1
and Y
2
and the moved rotating center
47
and
49
are moved to the suction port
31
from the standard rotating centers
35
and
37
as a beginning point.
The process or machining of the rotor chamber
5
is performed in such a manner as to drill each of the cylindrical portions
43
and
45
of the casing body in correspondence to the standard rotating centers
35
and
37
at first, and further to process each of the cylindrical portions
55
and
57
while moving the drill (or a formed end mill cutter instead of the drill) to the suction port
31
end at a predetermined distance L from each of the cylindrical portions
43
and
45
as in a manner mentioned above.
The rotor chamber
5
is expanded at a volume shown by an arrow
59
by processing the cylindrical portions
55
and
57
so as to expand in the above manner.
Further, a convex portion
61
is formed by crossing each of the cylindrical portions
55
and
57
in the suction port
31
end and a convex portion
63
is formed by crossing each of the cylindrical portions
43
and
45
in the discharge port
33
end.
Still further, when the respective components in the line X direction, the line Y
1
direction and the line Y
2
direction of the predetermined distance L is set to be x, y
1
and y
2
, these are selected among the range of 0.05 (mm)≦x, y
1
, y
2
≦0.3 (mm), and in this embodiment, x, y
1
and y
2
are respectively set to be 0.1 mm.
In the above manner, the supercharger in accordance with the first embodiment is structured.
In the supercharger, as mentioned above, in the rotor chamber
5
of the compressor
1
, the rotor chamber
5
is expanded by moving the standard rotating centers
35
and
37
of the cylindrical portions
43
and
45
to the moved rotating centers
47
and
49
at the distance L toward the suction port
31
end so as to process the cylindrical portions
55
and
57
.
In the compressor
1
, the discharge port
33
end becomes in a high temperature and the suction port
31
end becomes in a low temperature, however, even when the suction port
31
is displaced to the inner side by the expansion and the compression due to the temperature difference therebetween, or even when each of the rotors
7
and
9
is displaced to the suction port
31
end by the pressure difference between the suction port
31
and the discharge port
33
, the distortion of the casing and the displacement of each of the rotors
7
and
9
are absorbed by expanding the rotor chamber
5
to the cylindrical portions
55
and
57
from the cylindrical portions
43
and
45
.
Accordingly, the interference between the casing
3
and each of the rotors
7
and
9
can be prevented, so that the abrasion and the seizure of these elements, the poor motion of the compressor
1
and the like can be prevented.
In addition to this, the range of each of the components x, y
1
and y
2
given by the relation 0.05 (mm)≦x, y
1
, y
2
≦0.3 (mm) shows an optimum range of the distance L, and since the value of each of the components x, y
1
and y
2
is selected to 0.1 mm within this range as mentioned above, the interference between the casing
3
and each of the rotors
7
and
9
are prevented while maintaining a performance of the compressor
1
a normal condition.
Further, since the taper is given to the discharge port
33
so as to make the flow passage area wide toward the outer side, the flow speed change of the discharged intake air is reduced and the sound is reduced.
Next, a second embodiment in accordance with the present invention will be described below with reference to FIG.
6
. The embodiment is provided with the features stated in the fifth aspect to the eighth aspect.
FIG. 6
shows a Roots displacement compressor
65
as a fluid machine in accordance with the embodiment, and the compressor
65
is used for a supercharger of a vehicle.
As in the same manner as that of the compressor
1
in accordance with the first embodiment, the convex portion
61
is formed in the suction port
31
end of the casing
3
by crossing each of the cylindrical portions
55
and
57
to each other, and the convex portion
63
is formed in the discharge port
33
end by crossing each of the cylindrical portions
43
and
45
to each other.
In the case of the compressor
65
, as shown in
FIG. 6
, round portions
67
and
69
having a predetermined radius r are given to these convex portions
61
and
63
.
The predetermined radius “r” N is selected among a range of {fraction (1/10)}R (mm)≦r≦⅕R (mm) when the radius of the circles
43
and
45
corresponding to the rotating tracks
39
and
41
of the respective rotors
7
and
9
is set to be R.
Further, the radius r is adjusted in accordance with the deformation amount of the casing
3
different along the axial direction of each of the rotors
7
and
9
and the displacement amount of each of the rotors
7
and
9
, and an optimum radius r is given in all the range of the convex portions
61
and
63
along the axial direction of the rotors
7
and
9
.
More specifically, the radius r around the bearing members
83
and
85
which are located in both end portions of the rotors
7
and
9
is increasing to become a radius r′ in accordance with progressing toward around the suction port
31
and the discharge port
33
which are located in approximately middle portion of the rotor chamber
5
in the longitudinal direction thereof. The radius r′ located in the approximately middle portion of the rotor chamber
5
which is shown as dotted lines in
FIG. 6
, is larger than the radius r around the bearing members
83
and
85
.
The supercharger in accordance with the second embodiment is constituted in the above manner.
In the compressor
65
of the supercharger, as in the same manner as that of the compressor
1
mentioned above, since the cylindrical portions
55
and
57
are processed by moving the cylindrical portions
43
and
45
to the suction port
31
end at a degree of the distance L, the suction port
31
is displaced to the inner side due to the temperature difference, and even when each of the rotors
7
and
9
is displaced to the suction port
31
end due to the pressure difference, the interference between the casing
3
and each of the rotors
7
and
9
is prevented, so that the abrasion and the seizure between these elements, the poor motion in the compressor
65
and the like can be prevented.
In addition to this, in the compressor
65
, since the round portions
67
and
69
having a predetermined radius r are given to the convex portions
61
and
63
formed in both sides of the suction port
31
end and the discharge port
33
end, even when the casing
3
and each of the rotors
7
and
9
are interfered with each other by the displacement in the convex portion
61
close to the suction port
31
due to the temperature difference and the displacement of each of the rotors
7
and
9
due to the pressure difference, the abrasion and the seizure between each of the rotors
6
and
7
and the casing
3
can be prevented by the round portion
67
given to the convex portion
61
, and the poor motion in the compressor
65
can be prevented.
Further, the range of the radius r of the round portion given by the relation {fraction (1/10)}R (mm)≦r≦⅕R (mm) shows an optimum range of the radius r, and since the value of the radius r is selected among the range, the performance of the compressor
65
can be maintained in a normal condition while the abrasion, the seizure and the poor motion when the casing
3
and each of the rotors
7
and
9
are interfered with each other.
Still further, since the deformation amount of the casing
3
is different along the axial direction of each of the rotors
7
and
9
and the displacement of each of the rotors
7
and
9
is generated in such a manner that each of the rotors
7
and
9
swings around the bearing, thereby being different along the axial direction of each of the rotors
7
and
9
. Accordingly, as mentioned above, the radius r is adjusted in all the area of the convex portions
61
and
63
along the axial direction of the rotors
7
and
9
and the optimum radius r is given in each portion, so that the abrasion and the seizure between the convex portions
61
and
63
and each of the rotors
7
and
9
, the poor motion in the compressor
65
and the like can be effectively prevented.
Furthermore, the gap is formed between the casing
3
and each of the rotors
7
and
9
by the round portion
69
given in the convex portion
63
close to the discharge port
33
, the flow speed change of the discharged intake air can be reduced by the gap and the sound can be widely reduced.
Moreover, by making the flow passage area of the discharge port
33
wide toward the outer side, the flow speed change of the discharge intake air can be reduced and the sound can be reduced.
The structure in which the sound is widely reduced in the above manner is particularly advantageous for the Roots displacement fluid machine having a great sound in the discharge end such as the compressor
65
.
Further, the gap is formed between the casing
3
and each of the rotors
7
and
9
by the round portion
67
given in the convex portion
61
near the suction port
31
and the interference between the casing
3
and each of the rotors
7
and
9
can be prevented by the gap, so that the abrasion and the seizure between the casing
3
and each of the rotors
7
and
9
, the poor motion in the compressor
65
and the like can be prevented in the same manner as that of the first embodiment.
In this case, the fluid machine in accordance with the present invention can be used for a hydraulic motor which takes out a rotation force by a fluid pressure in addition to the compressor in the embodiments which moves the fluid by the rotation of the rotor.
While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
Claims
- 1. 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 Y1 and Y2 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 wherein 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, and a first component (x) of the predetermined distance in a direction of the vertical line (X) is set to he “x”, a relation 0.05 (mm)≦x≦0.3 (mm) is made and a second component (y1, y2) of the predetermined distance in a direction perpendicular to the vertical line (X) is set to be “y1” or “y2”, a relation 0.05 (mm)≦y1, y2≦0.3 (mm) is made.
- 2. The fluid machine according to claim 1, wherein each of the rotors is rotated by a prime mover and the fluid is sucked from the flow inlet port of the casing and is discharged from the flow outlet port.
- 3. 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; anda 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 Y1 and Y2 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 wherein 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, and wherein each of the cylindrical portions are crossed to each other so as to form a round portion having a predetermined radius r on one or both of a convex portion formed in the flow inlet port end and the flow outlet port end, and wherein when a radius of a circle corresponding to a rotating track of each of the rotors is set to be R, and the predetermined radius of the convex formed on the cross point between the first upper and lower cylindrical portions is set to be r, a relation {fraction (1/10)}R (mm)≦r≦⅕R (mm) is made.
- 4. The fluid machine according to claim 5, wherein each of the rotors is rotated by a prime mover and a fluid is sucked from a flow inlet port of the casing and is discharged from the flow outlet port.
- 5. 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; anda 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 Y1 and Y2 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 wherein 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, and wherein each of the cylindrical portions are crossed to each other so as to form a round portion having a predetermined radius r on one or both of a convex portion formed in the flow inlet port end and the flow outlet port end, and wherein the predetermined radius r is set to be a different value along an axial direction of each of the rotors.
- 6. The fluid machine according to claim 3, wherein each of the rotors is rotated by a prime mover and a fluid is sucked from a flow inlet port of the casing and is discharged from the flow outlet port.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9-025099 |
Feb 1997 |
JP |
|
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