Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2002-02-06
2003-04-22
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055400, C418S060000, C418S104000, C417S374000
Reexamination Certificate
active
06551081
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll-type compressor for a fuel cell. More particularly, the present invention relates to a scroll-type compressor that makes an exhausted gas from the fuel cell flow in again to additionally support the driving power of the compressor.
2. Description of the Related Art
Recently, a fuel cell has begun to attract attention as a drive source for electric cars. In a fuel cell, oxygen and hydrogen, compressed in advance by a compressor, are made to react to generate electricity. Water produced in the reaction, and a gas from which oxygen and hydrogen have been consumed is exhausted.
In most cases, the gas exhausted from the fuel cell maintains a state of high pressure. A scroll-type compressor equipped with a regeneration mechanism, which utilizes the energy produced by the expansion of the exhausted gas in the state of high pressure to additionally support the driving power of the compressor, has been disclosed in Japanese Unexamined Patent Publication (Kokai) No.2000-156237.
FIG. 4
is an axial cross-sectional view of the scroll-type compressor
100
with a regeneration mechanism. A housing
101
is the outer shell of the scroll-type compressor
100
. On a discharge side inner surface
102
of the housing
101
, a fixed scroll for compression
103
is erected in the direction of the motor. On a motor-side inner surface
104
, which opposes the discharge side inner surface
102
, a fixed scroll for expansion
105
is erected in the direction of discharge. Between these two fixed scrolls, a movable plate
106
, equipped with a shaft insertion portion
114
that opens toward the motor side in the center of the inner circumferential side, is provided.
On the inner circumferential side of the shaft insertion portion
114
, a bearing
115
to which a lubricant has been applied and two ring-seal members
117
that enclose the lubricant are provided. Moreover, into the further inner circumferential side of the bearing
115
, a crank-shaped drive shaft
110
is rotatably inserted.
On the discharge side surface of the movable plate
106
, a movable scroll for compression
107
is erected and on the motor-side surface of the movable plate
106
, a movable scroll for expansion
108
is erected. A compression chamber
111
is defined by the fixed scroll for compression
103
and the movable scroll for compression
107
. Moreover, a suction port
120
is formed on the outermost circumferential portion of the compression chamber
111
and a discharge port
121
is formed in the central portion of the inner circumferential side thereof, respectively.
On the other hand, an expansion chamber
112
is defined between the fixed scroll for expansion
105
and the movable scroll for expansion
108
. Moreover, an inflow port
130
is formed in the central portion of the inner circumferential side of the expansion chamber
112
and an outflow port
131
is formed on the outermost circumferential portion thereof, respectively.
On the outer circumferential portion of the movable plate
106
, a self-rotation preventing shaft
113
that prevents the self-rotation of the movable plate
106
is provided.
When the motor causes the drive shaft
110
to rotate and the movable scroll for compression
107
revolves, the air to be supplied to the fuel cell is sucked into the compression chamber
111
through the suction port
120
and moves toward the central side of the fixed scroll for compression
103
while being compressed. The compressed air is supplied to the fuel cell through the discharge port
121
. The air, the oxygen of which has been consumed in the reaction in the fuel cell, is exhausted from the fuel cell as an exhaust gas. Then the exhaust gas flows again into the inside of the expansion chamber
112
through the inflow port
130
and moves toward the outer circumferential side of the fixed scroll for expansion
105
while expanding. At this time, the expansion energy of the exhaust gas is converted into the drive energy of the drive shaft
110
. The expanded exhaust gas is exhausted to the outside of the compressor
100
through the outflow port
131
.
In such a conventional scroll-type compressor for a fuel cell, however, the exhaust gas of the fuel cell directly hits the seal member
117
when the exhaust gas flows into the inside of the expansion chamber
112
through the inflow port
130
. The exhaust gas contains water produced in the reaction in the fuel cell. On the other hand, the seal member
117
is provided in order to prevent the leakage of the lubricant from the bearing
115
, as described above. However, since the physical characteristic, such as the viscosity, of water differs from lubricant, it is difficult to prevent the water contained in the exhaust gas from entering by the seal member
117
. Therefore, in the conventional scroll-type compressor the lubricant is degraded due to the water that has entered the bearing
115
.
In this case, it seems to be possible to suppress the degradation of lubricant by decreasing the flow speed of the exhaust gas, that is, by decreasing the flow rate, to prevent water from entering. But, if the flow rate is reduced, the effect to additionally support the driving power of the compressor with the aid of the expansion energy of the compressed exhaust gas is also reduced.
SUMMARY OF THE INVENTION
The present invention has been developed and completed with the above-mentioned problems being taken into account, and the object is to provide a scroll-type compressor for a fuel cell that can prevent the water contained in the exhaust gas from entering the inside of the bearing and prevent the degradation of lubricant without decreasing the flow rate of the exhaust gas.
In order to solve the above-mentioned problems, the scroll-type compressor for a fuel cell of the present invention comprises: a fixed scroll for compression; a movable scroll for compression that defines a compression chamber, between the movable scroll for compression and the fixed scroll for compression, in which a gas sucked from the outer circumferential side is compressed by moving the gas in the direction of the inner circumference; a movable plate that has the movable scroll for compression erected on a first surface thereof and a cup-shaped cylindrical shaft insertion portion, which opens toward a second surface reverse to the first surface near the center and into which a drive shaft is inserted; a bearing that is provided inside the shaft insertion portion and supports the drive shaft with a lubricant therein; a fixed scroll for expansion provided in such a way as to oppose the second surface of the movable plate; a movable scroll for expansion that is erected on the second surface of the movable plate and defines an expansion chamber, between the movable scroll for expansion and the fixed scroll for expansion, in which the gas, which has flowed in through the inflow port formed near the center of the inner circumferential side, is expanded by moving the gas in the direction of the outer circumference; wherein the compressor also comprises a seal member that prevent the leakage of the lubricant through the opening end of the shaft insertion portion, and an obstruction member provided between the seal member and the inflow port to prevent water, contained in the gas, from entering the bearing within the shaft insertion portion by changing the flow of the gas, containing the water, that flows in through the inflow port.
In other words, the scroll-type compressor for the fuel cell of the present invention provides the obstruction member, that prevents the water contained in the exhaust gas from entering the bearing, in addition to the seal member. Conventionally, the exhaust gas flowing in through the inflow port directly hits the seal member and the water contained in the gas enters the inside of the bearing. In other words, no obstacle exists, that blocks the passage of the exhaust gas, between the inflow port and the seal member.
The scroll-type compressor for a fuel cell of the present
Nakane Yoshiyuki
Sowa Masato
Kabushiki Kaisha Toyota Jidoshokki
Vrablik John J.
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