Pumps – Successive stages
Reexamination Certificate
2000-09-07
2002-08-13
Walberg, Teresa (Department: 3742)
Pumps
Successive stages
Reexamination Certificate
active
06431840
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multistage high-pressure compressor having a multistage compression mechanism section which compresses an intake working fluid so as to generate a high pressure working fluid. More particularly, the present invention relates to a torque fluctuation suppressing device in an electric motor of the multistage high pressure compressor. The present invention also relates to a sealing device of a multistage high-pressure compressor, and more particularly to a seal structure between a cylinder and a member surrounding the outer periphery thereof.
2. Detailed Description of the Prior Art
A multistage high-pressure compressor including an electric motor provided in a lower part thereof and a compression mechanism section provided in an upper part thereof has been known. In such a multistage high-pressure compressor, the compression mechanism section has a plurality of compression sections, and reciprocates a piston with respect to a cylinder by the rotation of a rotating shaft which extends upwardly from the electric motor. The reciprocation of the piston causes an intake working fluid to be compressed through a plurality of compression stages, thereby generating a high-pressure working fluid. Examples of this type of multistage high-pressure compressor include a multistage compression device which is one of high-pressure gas compressors invented by the present applicant prior to the filing date of the present application. Such a multistage compression device is described in Japanese Patent Application Nos. 11-81781 and 11-46748, for example.
FIG. 1
illustrates a prior art showing a relationship between a compression mechanism section and an electric motor. In
FIG. 1
, reference numeral
20
denotes an electric motor. The electric motor
20
includes a stator
22
which has a coil
21
and is fixed to an inner surface of a motor casing
24
, and a rotor
25
which is provided inside the stator
22
and spaced from the stator
22
by a predetermined air gap. A rotating shaft
23
of the rotor
25
extends upwardly. A compression mechanism section
26
is provided above the electric motor
20
. Reference numerals
27
and
28
denote housing members attached to the upper and lower sides of the motor casing
24
. The motor casing
24
and the housing members
27
and
28
together contain the electric motor
20
. Reference numerals
29
and
30
denote bearings for rotatably supporting the rotating shaft
23
. Reference numeral is a detent key for preventing the rotor
25
from rotating with respect to the rotating shaft
23
.
In the above-described structure, a piston
32
is reciprocated with respect to a cylinder
31
of the compression mechanism section
26
by the rotation of the rotating shaft
23
. The reciprocation of the piston
32
causes a working fluid such as an intake gas to be compressed through four stages, thereby generating a high-pressure gas. The structure and operation of a high-pressure compressor of such a four-stage compression mechanism are described in the aforementioned Japanese Patent Application Nos. 11-81781 and 11-46748.
As illustrated in
FIG. 1
, the electric motor
20
includes the rotor
25
, in which a circular plate
33
for receiving the lower surface of the rotor
25
is fixed to the lower end of the rotating shaft
23
by a bolt
34
which is screwed into the rotating shaft
23
, thereby supporting the rotor
25
with respect to the rotating shaft
23
.
The detent key
35
which is disposed between the rotating shaft
23
and the rotor
25
is for preventing the rotor
25
from rotating with respect to the rotating shaft
23
. The whole detent key
35
is included in the rotor
25
.
As described above, the prior art requires the circular plate
33
which is provided for supporting the rotor
25
with respect to the rotating shaft
23
of the electric motor
20
. Thus, a torque fluctuation of the electric motor
20
occurs in the prior art case, and neither structures nor effects for suppressing such a torque fluctuation are provided in the prior art.
The second problem to be solved by the present invention will now be described in connection with a prior art multistage high-pressure compressor shown in
FIG. 2
to
FIG. 5. A
multistage high-pressure compressor
100
includes four compression sections (compression stage sections)
101
,
102
,
103
, and
104
, i.e., the compressor is the four-stage compressor. The compression sections
101
and
103
are disposed on a horizontal axis
106
, and the compression sections
102
and
104
are disposed on a horizontal axis
105
. A reciprocal compression mechanism is composed of cylinders
71
,
72
,
73
, and
74
which are fixed members, and pistons
51
,
52
,
53
, and
54
which are movable members reciprocating therein, arranged on the axes
106
and
105
.
First, a working fluid taken in from an intake tube
118
is compressed at the first stage compression section
101
. Next, the working fluid compressed at the first stage compression section
101
enters the second stage compression section
102
via a conduit
5
to be compressed. Then, the working fluid compressed at the second stage compression section
102
enters the third stage compression section
103
via a conduit
6
to be compressed. Thereafter, the working fluid compressed at the third stage compression section
103
enters the fourth stage compression section
104
via a conduit
7
to be compressed. The thus-obtained high-pressure working fluid with predetermined pressure and flow rate is output from a discharge tube
8
.
The working fluid in such a multistage high-pressure compressor
100
is a gas such as nitrogen, a natural gas, sulfur hexafluoride (SF
6
), and an air. The multistage compressor
100
can be applied to a natural gas filling machine for filling a natural gas into a Bombe (cylinder) of an automobile using a natural gas, a high pressure nitrogen gas supply to a gas injection molding machine which uses a high pressure nitrogen gas during injection molding of synthetic resin, filling machine for filling a high pressure air into an air Bombe, or the like.
In the multistage high-pressure compressor
100
, the piston
51
in the first stage compression section
101
and the piston
53
in the third stage compression section
103
are connected to a yoke
1
A on the axis
106
. A cross slider
2
A which is movably provided so as to cross the axis
106
in the yoke
1
A is connected to a crankshaft
4
via a crank pin
3
. The axes
105
and
106
cross at an angle of 90 degrees as viewed from the above. The piston
52
in the second stage compression section
102
and the piston
54
in the fourth stage compression section
104
are connected to a yoke
1
B on the axis
105
. A cross slider
2
B which is movably provided so as to cross the axis
105
in the yoke
1
B is connected to the crankshaft
4
via the crank pin
3
.
The crankshaft
4
is rotated by the electric motor
20
(see, e.g.,
FIG. 1
) which is provided below the compression sections
101
to
104
. The rotation of the crankshaft
4
causes the crank pin
3
which is provided eccentrically with respect to the crankshaft
4
to be rotated around the crankshaft
4
. Regarding the yoke
1
A, a displacement of the crank pin
3
in the direction of the axis
105
is accommodated by the movement of the cross slider
2
A, and a displacement of the crank pin
3
in the direction of the axis
106
is accommodated by the movement of the yoke
1
A. Accordingly, the pistons
51
and
53
reciprocate only in the direction of the axis
106
.
On the other hand, regarding the yoke
1
B, a displacement of the crank pin
3
in the direction of the axis
106
is accommodated by the movement of the cross slider
2
B, and a displacement of the crank pin
3
in the direction of the axis
105
is accommodated by the movement of the yoke
1
B. Accordingly, the pistons
52
and
54
reciprocate only in the direction of the axis
105
.
FIG. 5
is a cross-sectional view showing the structure
Aida Makoto
Mashimo Denji
Mizuno Takayuki
Nishikawa Hiroshi
Nishikawa Takahiro
Robinson Daniel
Sanyo Electric Co,. Ltd.
Walberg Teresa
Weingarten Schurgin, Gagnebin & Lebovici LLP
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