Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-05-25
2001-11-06
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
Reexamination Certificate
active
06312236
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a scroll compressor for use in air-conditioning apparatuses and the like, and in particular to configurational improvement of an Oldham's ring of a rotation preventing mechanism.
BACKGROUND OF THE TECHNOLOGY
As shown in
FIG. 6
, in a drive mechanism of this type of a scroll compressor in general, a shaft
3
is supported in a housing
1
by a bearing
2
, a boss portion is formed on the central portion of an orbiting scroll end plate
5
a
opposite a fixed scroll
4
, and the shaft
3
is coupled with an orbiting bushing
7
by affixing on the boss portion an orbiting bearing
6
in which the orbiting bushing
7
is inserted, thereby enabling orbiting motion of an orbiting scroll
5
relative to the fixed scroll
4
by the rotation of the shaft
3
. Also, a suction port
8
for sucking a refrigerant as a working fluid is provided on the housing
1
on the side of the low pressure chamber, and a discharge port
10
for discharging compressed refrigerant is provided on a housing
9
on the high pressure side.
In this configuration, a rotation preventing mechanism forces the orbiting scroll
5
to orbit while hampering its rotation. The mechanism includes first engagement means movable between an elliptical Oldham's ring
11
shown in FIGS.
7
(
a
) and
7
(
b
) and the orbiting scroll
5
only in a first radial direction (direction of the X-axis), and second engagement means movable between the housing
1
and the Oldham's ring
11
only in a second radial direction (direction of the Y-axis) perpendicular to the first radial direction.
The first engagement means comprises a pair of key ways (first key ways) provided on the orbiting scroll end plate
5
a
in the first radial direction and a pair of first keys
11
a
provided on the Oldham's ring
11
, each of the first keys respectively fitting with each of the first key ways and slidable along the first key ways and a thrust plate
12
. The second engagement means comprises a pair of key ways (second key ways) provided on the housing
1
in a second radial direction and a pair of second keys
11
b
provided on the Oldham's ring
11
, each of the second keys respectively fitting with each of the second key ways and slidable along the second key ways and the thrust plate
12
. The mechanism is configured in a manner such that the rotation of the orbiting scroll
5
is hampered by the first engagement means and the second engagement means while its orbiting motion is allowed. As another example, there is also a configuration in which a circular ring is used in place of the elliptical ring used in the ring portion of the Oldham's ring
11
.
However, in the above described construction of the rotation hampering mechanism, the Oldham's ring
11
is disposed in a manner such that each of the key pairs
11
a
and
11
b
are opposingly disposed respectively on the x- and y-axes (in the first and second radial directions) of an elliptical ring having major and minor axes. As a result, it suffered a problem of the key portions being damaged because reciprocating force of inertia of the Oldham's ring
11
increases during a high-speed high-pressure operation thus imposing an excessive load on the key portions. In order to secure a sufficient strength of the key portions, it is necessary to make the reciprocating force of inertia of the Oldham's ring
11
small. For this purpose, it is necessary to widen the ring width, ring diameter or the key widths of the Oldham's ring
11
, which will result in an increase in the size of the scroll compressor as a whole thus harming salability of the product.
DISCLOSURE OF THE INVENTION
The present invention addresses the above-described problems and is intended to provide a scroll compressor in which the strength of the key portions is enhanced without increasing the ring width, ring diameter or the key widths of the Oldham's ring.
In order to accomplish the above object, in the scroll compressor of the present invention, an Oldham's ring is provided with first and second keys opposingly disposed on a rotated elliptical ring formed by rotating an elliptical ring having the major axis and the minor axis respectively in a first radial direction (direction of the X-axis) disposed with the first keys and in a second radial direction (direction of the Y-axis) disposed with the second keys by a predetermined angle in the direction reverse to the direction of rotation of the shaft. This shortens the length of arm from the point of stress concentration in the base of the key portion on the side of each key on which a load is imposed without increasing the ring width, ring diameter or the key widths of the Oldham's ring, thus relieving the bending moments of the keys, controlling vibration during high-speed, high-pressure operation as well as enhancing the durability of the key portions.
To describe in detail, in the scroll compressor in accordance with the present invention, a rotation preventing mechanism comprises first engagement means disposed in between an Oldham's ring and an orbiting scroll and reciprocatingly movable only in a first radial direction, and second engagement means disposed between the Oldham's ring and a housing and reciprocatingly movable only in a second radial direction substantially perpendicular to the first radial direction. The first engagement means comprises a pair of key ways (first key ways) provided on an orbiting scroll end plate in the first radial direction and a pair of first keys provided on the Oldham's ring and respectively fitting in each of the first key ways and slidable along the first key ways, and the second engagement means comprises a pair of key ways (second key ways) provided in the housing in a second radial direction and a pair of second keys provided on the Oldham's ring and respectively fitting in each of the second key ways and slidable along the second key ways. The Oldham's ring is disposed in a manner such that the first pair of keys and the second pair of keys are respectively opposingly disposed in the first radial direction and the second radial direction on a rotated elliptical ring formed by rotating an elliptical ring having the major axis and the minor axis respectively in the first radial direction and in the second radial direction by a predetermined angle in the direction reverse to the direction of rotation of the shaft.
Also the Oldham's ring is configured in a manner such that a part of the elliptical curve between the axis of coordinates on the major axis side and axis of coordinates on the minor axis side of the rotated elliptical ring consists of an arc.
By employing the above configuration, on the surface of each key on which a load is imposed, the bending moment of the key can be relieved as the arm length from the point of stress concentration on the base of the key portion is shortened, thereby allowing enhancement of the strength of the key portion without increasing the ring width, ring diameter, or key width as well as miniaturization of the Oldham's ring and downsizing of the scroll compressor as a whole.
REFERENCES:
patent: 4325683 (1982-04-01), Miyazawa
patent: 5342184 (1994-08-01), Comparin et al.
patent: 63-88287 (1988-04-01), None
patent: 3-281996 (1991-12-01), None
patent: 4-219401 (1992-08-01), None
patent: 5-44659 (1993-02-01), None
Abe Yoshifumi
Fujita Takao
Iwasa Makoto
Matsushita Electric - Industrial Co., Ltd.
Vrablik John J.
Wenderoth , Lind & Ponack, L.L.P.
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