Rotary expansible chamber devices – Working member has planetary or planetating movement – Plural working members or chambers
Reexamination Certificate
2001-03-06
2001-11-06
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Plural working members or chambers
C418S076000, C418S077000, C418S094000, C418S100000
Reexamination Certificate
active
06312237
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates to a displacement type fluid machine such as a pump, a compressor and an expander.
(ii) Description of the Related Art
As conventional displacement type fluid machines, there are known a reciprocating fluid machine wherein a working fluid is driven by the manner that a piston repeats a reciprocation in a cylindrical cylinder, a rotary (rolling piston type) fluid machine wherein a working fluid is driven by the manner that a cylindrical piston is eccentrically rotated in a cylindrical cylinder, and a scroll fluid machine wherein a working fluid is driven by the manner that a pair of fixed scroll and orbiting scroll which have spiral wraps and stand up on end plates are engaged with each other and the orbiting scroll is gyrated.
The reciprocating fluid machine has some advantages in easiness of manufacture and inexpensiveness because of its simple construction. On the other hand, because the stroke from suction completion to discharge completion is short as 180° of the shaft angle so as to increase the flow velocity in discharge process, the reciprocating fluid machine has a problem that its performance deteriorates due to an increase of the pressure loss. Besides, because it is necessary to reciprocate the piston, the rotating shaft system can not be completely balanced. This causes another problem of a great vibration and noise.
In the rotary fluid machine, because the stroke from suction completion to discharge completion is 360° in the rotational angle of a rotating shaft, such a problem as an increase of the pressure loss in discharge process is less severe than in the reciprocating fluid machine. But, because the working fluid is discharged once per shaft rotation, there is a relatively wide variation of the gas compression torque. This causes a similar problem of vibration and noise to that in the reciprocating fluid machine.
In the scroll fluid machine, because the stroke from suction completion to discharge completion is long as 360° or more in the rotational angle of the rotating shaft (usually about 900° in case of a scroll fluid machine practically used as an air conditioner), the pressure loss in discharge process is little. Besides, because there is formed a plurality of working chambers in general, the variation of the gas compression torque in one rotation is little. This causes less vibration and noise. The scroll fluid machine is therefore advantageous on the above points. In the scroll fluid machine, however, it is necessary to maintain the clearance between the spiral wraps in engagement and the clearance between the end plate and a wrap tip. For this purpose, working with a high accuracy is required. This causes a problem of expensiveness in working. Besides, because the stroke from suction completion to discharge completion is long as 360° or more in the rotational angle of the rotating shaft, there is a problem that the longer the period of compression process is, the more the internal leakage increases.
One kind of displacement type fluid machine wherein a displacer for displacing a working fluid does not rotates relatively to a cylinder having sucked the working fluid but revolves, namely, gyrates with a substantially fixed radius to carry the working fluid, is proposed in Japanese Patent Unexamined Publication No. 55-23353 (cited reference 1), U.S. Pat. No. 2,112,890 (cited reference 2), Japanese Patent Unexamined Publication No. 5-202869 (cited reference 3), and Japanese Patent Unexamined Publication No. 6-280758 (cited reference 4). Such a displacement type fluid machine as proposed therein comprises a petal-shaped displacer having a plurality of members (vanes) radially extending from the center of the displacer, and a cylinder having a hollow portion of substantially the same shape as the displacer. The displacer gyrates in the cylinder to displace a working fluid.
The displacement type fluid machine disclosed in the above cited-references 1 to 4 has the following advantageous characteristics. Because it has no reciprocating part unlike the reciprocating fluid machine, its rotating shaft system can be completely balanced. This brings about a little vibration. Besides, because the sliding velocity between the displacer and cylinder is low, it is possible to relatively reduce the friction loss.
In this displacement type fluid machine, however, because the stroke from suction completion to discharge completion in each of working chambers defined by the vanes of the displacer and the cylinder, is short as about 180° (210°) of the rotational angle &thgr;
c
of the rotating shaft (almost a half of that of a rotary fluid machine and in the same extent of that of a reciprocating fluid machine), there is a problem that the flow velocity in discharge process increases and so the pressure loss increases to deteriorate the performance of the machine.
A displacement type fluid machine for solving the above problems is proposed in Japanese Patent Unexamined Publication No. 9-268987 (cited reference 5).
SUMMARY OF THE INVENTION
In the displacement type fluid machines described in the above cited-references 1 to 5, however, there has been found a new problem that the displacer and cylinder are worn away when the outer wall surface of the displacer slides on the inner wall surface of the cylinder.
It is an object of the present invention to provide a displacement type fluid machine comprising a displacer and a cylinder disposed between end plates such that a space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the cylinder is located on the center of the displacer, and a plurality of working chambers is formed when the positional relationship between the displacer and cylinder is directed to a gyration position, wherein the wear of the displacer and cylinder can be reduced.
According to the present invention, the above object can be attained by a displacement type fluid machine comprising a displacer and a cylinder disposed between end plates such that a space is formed by the inner wall surface of the cylinder and the outer wall surface of the displacer when the center of the cylinder is located on the center of the displacer, and a plurality of working chambers is formed when the positional relationship between the displacer and cylinder is directed to a gyration position, a suction port for introducing a fluid into one of the working chambers, a discharge port for discharging the fluid from the one of the working chambers, and an oil-feeding system for feeding a lubricating oil to the outer wall surface on the suction port side of the displacer and the inner wall surface of the cylinder opposite to the outer wall surface.
According to the present invention, the above object can be also attained by a displacement type fluid machine comprising a cylinder having an inner wall whose contour in a cross section is formed by a continuous curve, a displacer having an outer wall opposite to the inner wall of the cylinder for forming a plurality of working chambers by the outer wall in cooperation with the inner wall when the positional relationship between the displacer and cylinder is directed to a gyration position, a suction port for introducing a fluid to one of the working chambers, a discharge port for discharging the fluid from the one of the working chambers, and an oil-feeding system for feeding a lubricating oil to the suction port.
The present invention as described above has an effect that the friction loss can be reduced because sliding portions of the outer wall surface of the tip portion on the suction port side of the displacer and the inner wall surface of the cylinder can be fed with a lubricating oil.
REFERENCES:
patent: 336144 (1886-02-01), Nash
patent: 1277437 (1918-09-01), Lind
patent: 2112890 (1938-04-01), Gunn
patent: 6152714 (2000-11-01), Mitsuya et al.
patent: 6179593 (2001-01-01), Mitsuya et al.
patent: 6213743 (2001-04-01), Kohsokabe et al.
patent: 6217303 (2001-04-01), Kohsokabe et al.
pate
Kohsokabe Hirokatsu
Kouno Takeshi
Mitsuya Shunichi
Moriyama Kingo
Ohshima Yasuhiro
Antonelli Terry Stout & Kraus LLP
Denion Thomas
Hitachi , Ltd.
Trieu Thai-Ba
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