Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1999-12-17
2002-03-26
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055600, C418S088000, C418S094000
Reexamination Certificate
active
06361296
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a scroll-type compressor having a mechanism for preventing seizure of bearing for an orbiting scroll.
Various scroll-type compressors relating to the present invention have been proposed, and one example thereof is shown in FIG.
8
. In this figure, in a closed housing
8
, a scroll-type compressing mechanism C is housed at the upper part thereof and an electric motor M at the lower part thereof. The compressing mechanism C is connected to the electric motor M via a rotating shaft
5
so as to be driven by the electric motor M. The scroll-type compressing mechanism C includes a fixed scroll
1
, an orbiting scroll
2
, a rotation checking mechanism
3
such as an Oldham's ring, which permits orbital motion of the orbiting scroll
2
but checks rotation thereof, a frame
6
to which the fixed scroll
1
is fastened, and an upper bearing
71
, which pivotally supports the rotating shaft
5
.
The fixed scroll
1
has an end plate
11
and a spiral wrap
12
extending downward from the lower surface of the end plate
11
. The end plate
11
is provided with a discharge port
13
, which is formed by penetrating the end plate
11
, and a discharge valve
17
for opening/closing the discharge port
13
. The orbiting scroll
2
has an end plate
21
and a spiral wrap
22
extending upward from the upper surface of the end plate
21
. The two spiral wraps
12
and
22
are lapped in the radial direction. In a cylindrical boss
23
provided so as to extend downward from the lower surface of the end plate
21
, an eccentric bush
54
is rotatably inserted via an orbiting bearing
73
. Into a hole
55
defined by the eccentric bush
54
, an eccentric pin
53
protruding from the top end of the rotating shaft
5
is rotatably fitted. By engaging the spiral wraps
12
and
22
with each other so that the fixed scroll
1
and the orbiting scroll
2
are made off-centered by a predetermined distance and the angle thereof is shifted 180 degrees, a plurality of closed spaces
24
are formed. The spiral wraps
12
and
22
which form such closed spaces
24
are shown in
FIG. 7
of Japanese Patent Provisional Publication No. 7-63174 (No. 63174/1995), for example.
The frame
6
is fixed in the closed housing
8
, and the thrust surface
65
formed on the upper surface of the frame
6
is in slidable contact with the lower surface of the orbiting scroll
2
so that the orbiting scroll
2
is supported by the frame
6
. The thrust surface
65
is formed with an annular oil groove
66
. A hole circular in transverse cross section formed at the center of the upper surface of the frame
6
is closed by the lower surface of the orbiting scroll
2
, thereby defining an oil reservoir
61
. At the lower part of the inner wall surface of the frame
6
, which defines the oil reservoir
61
, is formed a oil discharge hole
62
so as to be inclined downward toward the outside in the radial direction.
A positive-displacement oil pump
51
is installed at the lower end of the rotating shaft
5
. A suction pipe
56
is connected to a suction port (not shown) of the oil pump
51
, and the tip end thereof is open in an oil sump
81
at the bottom of the closed housing
8
. A discharge port (not shown) of the oil pump
51
is connected to an oil supply hole
52
formed in the rotating shaft
5
in the axial direction.
By driving the electric motor M, the orbiting scroll
2
is driven via an orbital motion mechanism consisting of the rotating shaft
5
, eccentric pin
53
, eccentric bush
54
, boss
23
, etc. The orbiting scroll
2
performs orbital motion in the circular orbit with the orbiting radius while the rotation is checked by the rotation checking mechanism
3
.
By this motion, suction gas enters the closed housing
8
through a suction pipe
82
, being introduced into a suction passage
15
through a gas passage
85
, and sucked into the aforesaid closed spaces
24
. The suction gas reaches the central portion of the spiral wraps
12
,
22
while being compressed as the volume of the closed space
24
is decreased by the orbital motion of the orbiting scroll
2
, goes out through the discharge port
13
, and enters the discharge cavity
14
by pushing and opening the discharge valve
17
, being discharged from the discharge cavity
14
through a discharge pipe
83
.
On the other hand, since the oil pump
51
is also driven at the same time the electric motor M is driven, lubricating oil stored in the oil sump
81
at the bottom of the closed housing
8
is sucked via the suction pipe
56
, being sent to the oil supply hole
52
. The lubricating oil flows upward in the oil supply hole
52
. Some of the lubricating oil branches halfway from the main flow to lubricate a lower bearing
72
and the upper bearing
71
, and the main flow spouts from an opening of the oil supply hole
52
formed at the tip end of the eccentric pin
53
to lubricate the eccentric pin
53
and the orbiting bearing
73
, and enters the oil reservoir
61
. Subsequently, the lubricating oil passes through the oil groove
66
to lubricate sliding parts such as the thrust surface
65
and the rotation checking mechanism
3
. Also, some of the lubricating oil entering the oil reservoir
61
drops through the oil discharge hole
62
, passes through a passage
9
formed between the outer periphery of the stator of the electric motor M and the closed housing
8
, and then is stored in the oil sump
81
.
FIG. 9
is a view for illustrating the relationship between the eccentric bush
54
and the eccentric pin
53
in the above-described scroll-type compressor, being viewed from the upside, and
FIG. 10
is a sectional view for illustrating the relationship, viewed from the side. A flat portion of the eccentric bush
54
shown in the figure abuts on a flat portion at the outer periphery of the eccentric pin
53
, so that the eccentric bush
54
rotates integrally with the eccentric pin
53
. The lubricating oil discharged from the oil supply hole
52
is supplied to an oil supply path
57
defined between the flat portion formed at the outer periphery of the eccentric bush
54
as shown in the figure and the orbiting bearing
73
. Some of the lubricating oil is also supplied to a gap
58
formed between the outer periphery of the eccentric pin
53
necessary for the orbiting scroll
2
to perform orbital motion and the inner periphery of the eccentric bush
54
, and is introduced from the gap
58
to the oil reservoir
61
.
In the above-described scroll-type compressor, the lubricating oil discharged from the oil supply hole
52
in the eccentric pin
53
is distributed to the oil supply path
57
and the gap
58
. The lubricating oil going out from the oil supply hole
52
on the top end face of the eccentric pin
53
enters a concave
53
a
defined between the upper outer peripheral surface of the eccentric pin
53
and the inner peripheral edge of the eccentric bush
54
. From the concave
53
a,
some of the lubricating oil flows toward the oil supply path
57
, and some thereof enters the gap
58
. The oil distributed to the oil supply path
57
is supplied to the orbiting bearing
73
having a high sliding speed, and the oil distributed to the gap
58
is supplied to the flat portion of the eccentric pin having a low sliding speed; however, most of the lubricating oil drops into the oil reservoir
61
. Therefore, for the orbiting bearing
73
having a high sliding speed, the amount of oil in the oil supply path
57
is smaller than the necessary amount, so that there is a possibility for seizure of the bearing
73
to occur.
OBJECT AND SUMMARY OF THE INVENTION
The present invention was made in view of the above situation, and accordingly an object thereof is to provide a scroll-type compressor which solves the above problem and can supply sufficient lubricating oil without the occurrence of seizure of bearing.
To achieve the above object, the present invention provides a scroll-type compressor comprising a closed housing having a gas inlet and outlet; a
Hirooka Katsumi
Kobayashi Hiroyuki
Matsuda Susumu
Alston & Bird LLP
Vrablik John J.
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