Rotary expansible chamber devices – With removal or accommodation of solid foreign material in... – With filter
Reexamination Certificate
2000-01-03
2001-05-08
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
With removal or accommodation of solid foreign material in...
With filter
C418S088000, C418S089000
Reexamination Certificate
active
06227828
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an electrically-operated sealed compressor such as, for example, a scroll compressor or a rotary compressor for use in air conditioners, refrigerators or the like and, more particularly, to a gear pump mounted in the electrically-operated sealed compressor.
2. Description of Related Art
Conventionally, an electrically-operated sealed compressor such as a scroll compressor or a rotary compressor is generally used in a cooling apparatus for air conditioners, refrigerators, or the like. This kind of conventional compressor is discussed hereinafter taking the case of a scroll compressor.
As shown in
FIG. 14
, a sealed vessel
10
accommodates a compression mechanism
1
, an electric motor
7
including a stator
5
and a rotor
6
, a crankshaft
2
for transmitting the rotational force of the electric motor
7
to the compression mechanism
1
, a main bearing
3
for supporting one end of the crankshaft
2
, and an auxiliary bearing
4
a
having a bearing holder
4
for supporting the other end of the crankshaft
2
. The main bearing
3
has a container
11
attached thereto for temporarily collecting oil which has been supplied to the bearing portions for lubrication thereof. The sealed vessel
10
is provided with a suction pipe
8
for sucking in a low-pressure refrigerant gas and a discharge pipe
9
for discharging a high-pressure refrigerant gas compressed by the compression mechanism
1
to the outside of the sealed vessel
10
. The crankshaft
2
has a gear pump
150
attached to the end thereof which is supported by the auxiliary bearing
4
a.
In the above-described construction, when the rotor
6
of the electric motor
7
rotates, the rotational force thereof is transmitted to the compression mechanism
1
by the crankshaft
2
, to thereby compress a refrigerant gas. More specifically, the compression mechanism
1
compresses the low-pressure refrigerant gas drawn through the suction pipe
8
into a high-pressure refrigerant gas, which is in turn discharged into a discharge side space
14
defined in the sealed vessel
10
. Thereafter, the high-pressure refrigerant gas passes through a communication hole
12
defined in the main bearing
3
and enters an electric motor side space
17
. The main current of the high-pressure refrigerant gas passes through a cutout defined in the stator
5
and enters an auxiliary bearing side space
18
before it is eventually discharged into a refrigerating cycle (not shown) through the discharge pipe
9
.
On the other hand, the gear pump
150
has a pump casing
151
including a pair of gears
52
, a strainer
157
, a foreign substance storage chamber
155
for storing foreign substances captured by the strainer
157
, and an oil suction nozzle
156
. The pump casing
151
is covered with a cover plate
153
fastened thereto by a plurality of, for example four, screws
152
, and has a recess
60
a
defined therein so that a gear chamber
60
for accommodating the gear pair
52
therein may be formed by the cover plate
153
and the recess
60
a
. The fastening force of the screws
152
maintains the tightness between the pump casing
151
and the cover plate
153
to ensure sealing properties to the oil and the refrigerant gas.
As shown in
FIGS. 15 and 16
, the pump casing
151
has an oil well
61
defined therein and adjoining the gear chamber
60
so that the gear pair
52
may be supplied with the oil which serves as lubricating and sealing oil at the starting of the pump. The strainer
157
comprises a stainless screen
157
a
sandwiched between two stainless frames
157
b
and spot-welded thereto, and a plurality of elastic members or pieces
157
c
protruding therefrom. As shown in
FIG. 16
, when the strainer
157
is mounted in the pump casing
151
, the elastic members
157
c
act to bias the strainer
157
against its mounting surface on the pump casing
151
to prevent the foreign substances in the foreign substance storage chamber
155
from entering the gear chamber
60
.
The gear pump
150
has an insert formed thereon and inserted into an associated portion of the bearing holder
4
, and the pump casing
151
is fastened to its seat formed on the bearing holder
4
by a plurality of (for example two) bolts
154
. As shown in
FIG. 15
, the gear pair
52
is comprised of an outer gear
52
a
and an inner gear
52
b
in mesh with each other. That end of the crankshaft
2
to which the gear pump
150
is attached has a cutout so as to present a generally D-shaped section and is inserted into a center hole of an inner gear
52
b
having a corresponding shape. The driving force of the electric motor
7
is transmitted to the inner gear
52
b
via the D-shaped portion of the crankshaft
2
and that of the inner gear
52
b
to cause the outer and inner gears
52
a
and
52
b
to undergo a mutual rotation for pumping action.
When the compressor is in operation, the lubricating oil in an oil sump
15
formed at a lower portion of the sealed vessel
10
is sucked up into the inside of the gear pump
150
through the oil suction nozzle
156
, and is then introduced into the space defined between the outer and inner gears
52
a
and
52
b
after having-passed through the:strainer
157
for filtering of foreign substances contained therein. Thereafter, the lubricating oil is fed into an oil passage
153
b
defined in the cover plate
153
by the pumping action of the gear pair
52
, passes through a through-hole defined in the crankshaft
2
along the center line thereof, and is fed to the compression mechanism
1
. Most of the lubricating oil acts to lubricate the sliding surfaces of the main bearing
3
and the crankshaft
2
and is then collected in the oil collecting container
11
attached to the main bearing
3
. The lubricating oil thus collected in the container
11
is discharged therefrom through a discharge port
11
a
defined therein and drops by its own gravity to return to the oil sump
15
formed at the lower portion of the sealed vessel
10
. The remaining oil together with the high-pressure refrigerant gas is discharged from the compression mechanism
1
into the sealed vessel
10
and is separated from the high-pressure refrigerant gas during movement thereof inside the compressor. This lubricating oil also drops by its own gravity to return to the oil sump
15
.
According to the above-described conventional compressor, however, because the pump casing includes the strainer, the foreign substance storage chamber, and the oil suction nozzle in addition to the gear pair, the height of the pump casing becomes large in the longitudinal direction of the compressor. The height depends on the size required for mounting the. strainer, the size appropriate to the volume required for the foreign substance storage chamber, and the size appropriate to the diameter of the oil suction nozzle. On the other hand, the gear chamber accommodating the gear pair and formed in the pump casing is covered with the cover plate screwed to the pump casing, thus inevitably elongating the total longitudinal length of the bearing holder and the gear pair.
For these reasons, in the event that the crankshaft undergoes a whirling motion having tilted from the ideal axis of the crankshaft, the gear pair is also affected by the whirling motion of the crankshaft and will undergo an eccentric motion relative to the ideal axis of the crankshaft. More specifically, the inner and outer gears forming the gear pair rotate relative to each other with their gear teeth clashing against each other during rotation of the crankshaft that is then undergoing the whirling motion. Clashing of the gear teeth eventually leads to an abnormal wear of the gear teeth, the wall surface of the gear chamber, the driving portion of the crankshaft for driving the gear pair or the like. It may also generate abnormal sounds during operation of the compressor, resulting in a lowering in performance and also in reliability of the compressor.
To overcome this kind of problem, it is n
Aburaya Kiyoji
Aoshika Shoji
Narita Tsutayoshi
Sakai Manabu
Takeuchi Yoshiharu
Matsushita Electric - Industrial Co., Ltd.
Vrablik John J.
Wenderoth , Lind & Ponack, L.L.P.
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