Rotary expansible chamber devices – Working member has planetary or planetating movement – Plural working members or chambers
Reexamination Certificate
1998-07-29
2001-02-06
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Plural working members or chambers
C418S055300
Reexamination Certificate
active
06183228
ABSTRACT:
TECHNICAL FIELD
The present invention relates to, for example, a pump, a compressor, an expander, etc., more specifically to a displacement type fluid machine.
BACKGROUND ART
As a conventional displacement type fluid machine, a reciprocating fluid machine for moving a working fluid by repeating a reciprocation of a piston in a cylindrical cylinder, a rotary (rolling piston type) fluid machine for moving a working fluid by eccentrically rotating a cylindrical piston in a cylindrical cylinder, a scroll fluid machine for moving a working fluid by engaging a pair of fixed scroll and orbiting scroll, which have spiral wraps and stand up on end plates, with each other and by gyrating the orbiting scroll, are well known.
Since the reciprocating fluid machine is simply constructed, it is possible to prepare the machine easily and to be inexpensive. On the other hand, since the process from suction completion to discharge completion is short of the shaft angle of 180° so that a flow velocity of the process for the discharge gets faster, there is a problem that the pressure loss is increased so that the performance is reduced. Further, since it is necessary to reciprocate the piston, so that a rotary shaft system can not be completely balanced, there is another problem that a vibration and a noise are larger.
Also, in case of the rotary fluid machine, since the process from suction completion to discharge completion has the shaft angle of 360°, there is less problem that the pressure loss during the discharge process is increased compared to the reciprocating fluid machine. However, since the working fluid is discharged once per one rotation of the shaft, the variation of a gas compression torque is relatively higher, accordingly, there is the same problem of the vibration and noise as the reciprocating fluid machine.
Further, in case of the scroll fluid machine, since the process from suction completion to discharge completion has the long shaft angle of 360° or more (the scroll fluid machine practically used as an air conditioner has usually 900°), so that the pressure loss during the process of discharge is low, a plurality of working chambers are formed generally, so that there is an advantage that the variation of the gas compression torque is low and the vibration and noise are less. When the wraps are engaged, it is necessary to manage the clearance between the spiral wraps and the clearance between the end plate and a wrap tip. Thus, the fluid machine must be worked with high accuracy, so that there is further problem that the expense of working is expensive. Further, since the process from suction completion to discharge completion has the long shaft angle of 360° or more, it takes a long time for the compression process, so that there is further problem that the internal leakage is increased.
By the way, known is a displacement type fluid machine in which a displacer for moving a working fluid is not rotated relative to a cylinder in which the working fluid is suctioned, but is gyrated with an almost constant radius, that is, is gyrated to transmit the working fluid. This kind of displacement type fluid machines have been proposed in Japanese Patent Unexamined Publication No. 55-23353 (Document 1), U.S. Pat. No. 2,112,890 (Document 2), Japanese Patent Unexamined Publication No. 5-202869 (Document 3) and Japanese Patent Unexamined Publication No. 6-280758 (Document 4). Such a displacement type fluid machine as proposed therein comprises a petal-shaped piston having a plurality of members (vanes) radially extending from the center and a cylinder having a hollow portion of almost the same shape as the piston, wherein the piston is gyrated in the cylinder so as to move the working fluid.
DISCLOSURE OF THE INVENTION
Since Such a displacement type fluid machine as shown in the Documents 1 to 4 do not have a portion for reciprocation unlike the reciprocating fluid machine, it is possible to balance the rotary shaft system completely. Thus, since the vibration is low, further the sliding velocity between the piston and the cylinder is low, the displacement type fluid machine is essentially provided with an advantageous characteristic that it is possible to reduce the friction loss.
However, the process from suction completion to discharge completion in each working chamber formed by plural vanes, which constitute a piston, and the cylinder has the short shaft angle &thgr;c of about 180° (210°) (about a half of that of a rotary fluid machine and the same level as a reciprocating fluid machine), the flow velocity during the discharge process gets faster, there is further problem that the pressure loss is increased, so that the performance is reduced. Also, in such fluid machines as described in those Documents, the shaft angle from a suction completion to a discharge completion in each working chamber is small and a time lag is occurred for the duration from the discharge completion to the next (compression) process (another suction completion) start and the working chamber from the suction completion to the discharge completion is one-sided around a drive shaft to be formed. Therefore, such a fluid machine is not dynamically balanced and a rotating moment for prompting the piston itself to be rotated is excessively applied to the piston as a reaction from the compressed working fluid, thereby there is further problem in reliability that the friction and abrasion of the vanes are occurred.
For solving this problem, developed was a displacement type fluid machine in which a displacer and a cylinder are located between end plates, a space is formed by an inner wall surface of said cylinder and an outer wall surface of said displacer when the center of said displacer is located on the center of said cylinder, and a plurality of spaces are formed when the positional relationship between said displacer and said cylinder is for a gyration, wherein said inner wall surface of said cylinder and said outer wall surface of said displacer are formed so that the maximum value of the number of spaces among said plurality of spaces in the process from a suction completion to a discharge completion is not less than the number of protrusions protruding inwardly of said cylinder (a displacement type fluid machine in which a displacer and a cylinder are located between end plates, a space is formed by an inner wall surface of said cylinder and an outer wall surface of said displacer when the center of said displacer is located on the center of said cylinder, and a plurality of spaces are formed when the positional relationship between said displacer and said cylinder is for a gyration, wherein said inner wall surface of said cylinder and said outer wall surface of said displacer are formed so that the shaft angle &thgr;c in the process from a suction completion to a discharge completion in said plurality of spaces satisfies the following expression:
(((N−1)/N·360)<&thgr;c≦375 (degree)
where N is the number of protrusions protruding inwardly of said cylinder. This displacement type fluid machine has characteristics that the fluid loss in the discharge process can be decreased to the extent of that of a scroll fluid machine and the manufacture is easier than that of the scroll fluid machine.
By the way, when a displacement type fluid machine in which a displacer and a cylinder are located between end plates, a space is formed by an inner wall surface of said cylinder and an outer wall surface of said displacer when the center of said displacer is located on the center of said cylinder, and a plurality of spaces are formed when the positional relationship between said displacer and said cylinder is for a gyration, as described in the above documents including the above developed one, is operated as a compressor, a problem arose that the whole adiabatic efficiency lowered especially in a high speed range.
An object of the present invention is to provide a displacement type fluid machine in which the deterioration of the performance can be restrained in a practical operation.
The above object is a
Hata Hiroaki
Inaba Koichi
Kohsokabe Hirokatsu
Machida Shigeru
Mitsuya Shunichi
Antonelli Terry Stout & Kraus LLP
Denion Thomas
Hitachi , Ltd.
Trieu Thai Ba
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