Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1999-12-14
2001-08-21
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S100000
Reexamination Certificate
active
06276910
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll-type compressor, and, more specifically, to a scroll-type compressor in which oil is introduced from a suction port into the interior of a housing when the compressor is assembled.
2. Description of Related Art
A scroll-type compressor is a fluid displacement apparatus wherein a pair of spiral elements are engaged to each other at an angular and radial offset. Orbital movement between the pair of spiral elements creates fluid pockets that are moved inwardly and change in volume to compress a fluid sucked from a suction chamber to the fluid pockets. The compressed fluid is discharged from the fluid pockets to a discharge chamber.
For example, as depicted in
FIG. 3
, a known scroll-type compressor has a housing
10
. Housing
10
includes a rear housing
101
and a front housing
100
. Front housing
100
includes a large-diameter cylindrical portion
103
fixed to an open end of rear housing
101
, and a small-diameter cylindrical portion
105
. Rear housing
101
and front housing
100
are aligned coaxially.
Drive shaft
11
is provided on a center axis X of housing
10
. Drive shaft
11
extends to the interior of housing
10
through small-diameter cylindrical portion
105
of front housing
100
. Drive shaft
11
includes a small-diameter portion
11
a
surrounded by small-diameter cylindrical portion
105
of front housing
100
, and a large-diameter portion
11
b
surrounded by large-diameter cylindrical portion
103
of front housing
100
. Drive pin
12
is fixed to the end of large-diameter portion
11
b
. Drive pin
12
extends in parallel to axis X and at a position eccentric from axis X. Large-diameter portion
11
b
is rotatably supported in cylindrical portion
103
via needle bearing
13
. Small-diameter portion
11
a
is rotatably supported in cylindrical portion
105
via ball bearing
14
.
An electromagnetic clutch
15
is supported on the outer surface of small-diameter cylindrical portion
105
, and rotates via bearing
15
d
. Electromagnetic clutch
15
has a pulley
15
a
that is connected to an external drive source (not shown) by a V-type belt (not shown), and a rotation transmitting plate
15
c
that is fixed to the end of small-diameter portion
11
a
. Drive shaft
11
is driven by the external drive source via the clutch mechanism.
A first scroll member
16
, known as a fixed scroll member, and a second scroll member
20
, known as an orbital scroll member, are disposed within rear housing
101
. First scroll member
16
has a disc-like first end plate
16
a
that is disposed coaxially along axis X and fitted into rear housing
101
, and a first spiral element
16
b
that axially extends into an interior of rear housing
101
a surface of first end plate
16
a
. A leg portion
16
c
is formed an opposite surface of first end plate
16
a
. The top surface of leg portion
16
c
is in contact with the inner surface of bottom portion
101
a
. First scroll member
16
is fixed to rear housing
101
by bolt
17
inserted into leg portion
16
c
through bottom portion
101
a
. The interior of rear housing
101
is partitioned into a suction chamber
18
and a discharge chamber
19
by first end plate
16
a
of first scroll member
16
.
Second scroll member
20
is disposed adjacent to first scroll member
16
in rear housing
101
. Second scroll member
20
has a disc-like second end plate
20
a
disposed along axis Y that is radially offset from axis x by an amount of rs, and a second spiral element
20
b
that axially extends into the interior of rear housing
101
on a surface of second end plate
20
a
. Further, second scroll member
20
has a ring-shaped boss
20
c
formed on an opposite surface of second end plate
20
a
. Axis Y of second end plate
20
a
is positioned eccentric from axis X by an amount of rs. Second spiral element
20
b
of second scroll member
20
engages first spiral element
16
b
of first scroll member
16
at an angular offset of 180 degrees.
A suction port
18
a
that communicates with suction chamber
18
, and a discharge port
19
a
that communicates with discharge chamber
19
are provided within rear housing
101
. Referring to
FIG. 3
, suction port
18
a
opens foward second spiral element
20
b
of second scroll member
20
. Although second scroll member
20
moves according to an orbital motion, as depicted in
FIG. 3
, second spiral element
20
b
is located at a position near suction port
18
a
, such that suction port
18
a
is almost closed by the outer surface of second spiral element
20
b
. Such an alignment may be employed in a compressor for an air conditioner for vehicles so that the compressor size is reduced. Typically, oil is introduced initially into suction chamber
18
through suction port
18
a
and enclosed in housing
100
when the compressor is assembled.
An eccentric bush
21
is disposed rotatably in boss
20
c
via needle bearing
22
. Eccentric bush
21
is formed as a cylindrical body having a relatively large thickness, and disposed coaxially with second end plate
20
a
. An eccentric through hole
21
a
extends in parallel to axis X, and is defined in eccentric bush
21
. A counter weight
23
is fixed to eccentric bush
21
. Counter weight
23
extends in the radial direction of eccentric bush
21
. Drive pin
12
is fixed to the end of large-diameter portion
11
b
of drive shaft
11
, and is inserted slidably into through hole
21
a
of eccentric bush
21
. Pin
21
b
is fixed to eccentric bush
21
and connects eccentric bush
21
and counter weight
23
.
A race
24
is formed as a ring plate, and is fixed to the end surface of large-diameter cylindrical portion
103
of front housing
100
. A race
25
is formed as a ring plate and is positioned to face race
24
. Race
25
is fixed to the side surface of second end plate
20
a
of second scroll member
20
. A plurality of balls
26
are interposed between races
24
and
25
. Races
24
and
25
, and balls
26
form a ball coupling mechanism for preventing rotation of second scroll member
20
while allowing revolution of second scroll member
20
.
In such a scroll-type compressor, balls
26
roll along a circular route as defined between races
24
and
25
that has about the same radius as the radius of revolution rs of second scroll member
20
. Balls
26
may roll while being pressed against races
24
and
25
. Consequently, second scroll member
20
revolves while maintaining a predetermined angular relationship relative to front housing
100
and relative to first scroll member
16
.
When the scroll-type compressor initially is assembled, oil is introduced into suction chamber
18
through suction port
18
a
. However, if oil is introduced into suction chamber
18
when second spiral element
20
b
of second scroll member
20
is located at a position near suction port
18
a
, such that suction port
18
a
is about closed by the outer surface of second spiral element
20
b
, then oil may overflow from suction port
18
a
to the outside of the compressor. This overflow may occur because the oil does not completely enter into suction chamber
18
through suction port
18
a
. In particular, when oil is introduced at an increased flow rate, oil may overflow from suction port
18
a
to the outside of the compressor. In order to avoid overflows, oil is introduced into suction chamber
18
after the position of second spiral element
20
b
of second scroll member
20
is shifted away from suction port
18
a
by hand rotating drive shaft
11
. Such a procedure consumes time, thereby reducing the productivity of the compressor assembling operations.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved structure for a scroll-type compressor that allows the introduction of oil at an increased flow rate regardless the position of a scroll member when the compressor is assembled, thereby increasing the productivity of the compressor assembling operations.
To achieve the foregoing and other objects,
Baker & Botts L.L.P.
Sanden Corporation
Vrablik John J.
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