Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2002-06-26
2003-06-24
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055500
Reexamination Certificate
active
06582210
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll compressor used for a refrigerating machine, an air conditioner and the like.
2. Description of the Related Art
FIG. 5
shows a longitudinal sectional view of a compression mechanism part of a conventional scroll type refrigerant compressor disclosed in Japanese Unexamined Patent Publication No. 2000-337276. In
FIG. 5
, a fixed scroll
1
, a seat
1
a
of the fixed scroll
1
, a spiral blade
1
b
of the fixed scroll
1
, an orbiting scroll
2
, a seat
2
a
of the orbiting scroll
2
, and a spiral blade
2
b
of the orbiting scroll
2
are provided. An orbiting bearing
2
c
is provided at a central part of the surface of the orbiting scroll opposite to the surface where the spiral blade
2
b
of the orbiting scroll
2
exists. A thrust surface
2
d
is formed on the end of the surface where the orbiting bearing
2
c
is provided. The orbiting scroll
2
is connected with an eccentric part
4
a
of a main shaft
4
through the orbiting bearing
2
c
. The eccentric part
4
a
is off-center by r shown in
FIG. 5
with respect to the center line of the main shaft
4
, and the amount of r is specified by the following formula.
r=
1/2
P−
1/2(
To+Tf
)
P: spiral pitch (distance between blade sides),
To: spiral blade thickness of orbiting scroll
Tf: spiral blade thickness of fixed scroll
The orbiting scroll
2
executes an orbiting motion to the fixed scroll
1
based on a rotation of the main shaft
4
and a rotation suppression by an Oldham coupling
6
, which causes a fluid compression. The main shaft
4
is supported in the radial direction by a main bearing
3
b
having a sliding member between the main bearing
3
b
and a compliant frame
3
.
A rotor
8
is fitted and engaged with the main shaft
4
, and the main shaft
4
is driven by a motor rotation based on the rotor
8
and a stator
9
. There is a space
10
between an external diameter
8
a
of the rotor
8
and an internal diameter
9
a
of the stator
9
in order to avoid the rotor
8
contacting the stator
9
during the rotation. A thrust surface
3
a
is formed on the compliant frame
3
which supports a thrust surface
2
d
of the orbiting scroll
2
in the axial direction. The compliant frame
3
supports a main shaft load generated during operation, at the main bearing
3
b
in the direction of radius. In order to support the load at a guide frame
5
, an upper fitting surface
3
c
and a lower fitting surface
3
d
are formed on the compliant frame
3
. The upper fitting surface
3
c
is fitted and engaged with an upper fitting surface
5
a
of the guide frame
5
in the radial direction with having a minute space, and the lower fitting surface
3
d
is fitted and engaged with a lower fitting surface
5
b
in the radial direction with having a minute space. The clearances (spaces) at the upper fitting surface and the lower fitting surface between the compliant frame and the guide frame are set to be almost equal.
With respect to the radial direction, the compliant frame
3
in operation moves in the direction of a load which the main bearing receives from the main shaft, by the amount of the clearance. The upper fitting surface
3
c
of the compliant frame
3
contacts the upper fitting surface
5
a
of the guide frame
5
in the load direction of the main bearing, and the lower fitting surface
3
d
of the compliant frame
3
contacts the lower fitting surface
5
b
of the guide frame
5
in the load direction of the main bearing. As the load direction of the main bearing continuously changes 360 degrees during one rotation, the compliant frame
3
performs a minute orbiting motion in the guide frame
5
. In addition, as the compliant frame
3
shifts in the radial direction, the space
10
between the rotor and the stator is reduced by the amount of the shifting.
In the conventional scroll compressor, as stated above, the upper fitting surface
3
c
and the lower fitting surface
3
d
are formed on the compliant frame
3
, and each of the upper fitting surface
3
c
and the lower fitting surface
3
d
is fitted and engaged with the upper fitting surface
5
a
or the lower fitting surface
5
b
on the guide frame
5
, with having a space in the direction of radius. Then, the compliant frame
3
moves in the direction of the load received from the main bearing, by the amount of the space. Relating to this movement, the orbiting scroll interlocked through the main shaft and the bearing, also moves in the direction of radius. According as the compliant frame moves, the orbiting scroll moves by the amount of a clearance from the original rotation center, a side space between the swirl of the orbiting scroll and the swirl of the fixed scroll is extended. As the swirl of the orbiting scroll makes the side space extend with respect to the swirl of the fixed scroll, a leak from the swirl side in the scroll compression chamber is increased, which causes performance deterioration. Further, as the compliant frame
3
moves depending upon the space, the axis of the rotor interlocked with the main shaft also moves, which causes a contact problem of the external diameter of the rotor with the internal diameter of the stator.
Though the clearances between the compliant frame and the guide frame at the upper and lower fitting surfaces are set up to be almost equal, it is difficult to make the clearances at the upper and lower completely equal in every scroll compressor made in mass production. Therefore, the clearances at the upper fitting surface and the lower fitting surface are different in the range of a specific allowance. In some cases, the compliant frame contacts the guide frame at either the upper fitting surface or the lower fitting surface and does not contact at the other surface during operation, which causes a change of vibrations of the axial system and a change of noises of the axial system, a performance fall based on increasing of the contact of the spiral blade top, and an increase of wear of the contact part at the blade top.
Moreover, the compliant frame
3
in operation moves in the direction of a load which the main bearing receives from the main shaft, with respect to the radial direction, by the amount of the clearance. The upper fitting surface
3
c
of the compliant frame
3
contacts the upper fitting surface
5
a
of the guide frame
5
in the load direction of the main bearing, and the lower fitting surface
3
d
of the compliant frame
3
contacts the lower fitting surface
5
b
of the guide frame
5
in the load direction of the main bearing. As the load direction of the main bearing continuously changes 360 degrees during one rotation, the compliant frame
3
performs a minute orbiting motion in the guide frame
5
. However, when the compliant frame
3
itself performs a rotational movement to the guide frame, there is a problem that a loss friction is generated at the part where the compliant frame
3
contacts with the upper and lower fitting surfaces
5
a
and
5
b
of the guide frame
5
and wear is also generated. Further, there is a problem that thickness of oil film of the main bearing is reduced and a load faculty of the bearing is also decreased because the relative rotation rate of the main bearing of the compliant frame and the main shaft falls.
In order to solve these problems, a rotation prevention structure for regulating the rotation of the compliant frame is formed between the guide frame and the compliant frame in the conventional scroll compressor. This rotation prevention structure is composed of combination of a reamer pin and a reamer hole, and regulates the rotation of the compliant frame by being associated with the reamer pin inserted in the guide frame. However, as a clearance between a diameter of the reamer pin and a diameter of the reamer hole is small, the state occurs that only the reamer pin receives a gas compression load during operation, which causes a problem of a smooth minute orbiting motion being impeded within the guide frame of the compliant
Fushiki Takeshi
Ikeda Kiyoharu
Nishiki Teruhiko
Ogawa Yoshihide
Sano Fumiaki
Mitsubishi Denki & Kabushiki Kaisha
Vrablik John J.
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