Scroll type fluid machinery

Details Scroll type fluid machinery Scroll type fluid machinery

2000-08-09

2001-12-18

Denion, Thomas (Department: 3748)

Rotary expansible chamber devices

Working member has planetary or planetating movement

Helical working member, e.g., scroll

C418S057000, C464S102000

Reexamination Certificate

active

06331102

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll type fluid machine to be used as a compressor or an expander, particularly, relates to a mechanism preventing rotation of a swiveling scroll.
This application is based on Japanese Patent Application Nos. Hei 10-350262 and Hei 11-203922 the contents of which are incorporated herein by reference.
2. Discussion of the Background
A mechanism preventing rotation of a swiveling scroll, for example, as shown in Japanese Unexamined Patent Application, First Publication, Nos. Sho 58-20401 (Kokai) and Sho 59-68585 (Kokai), having a swiveling scroll
1
comprising an end plate
1
a
and a swivel pin
1
b
provided projectingly from the end plate
1
a,
a housing
2
comprising a housing pin
2
a
provided projectingly from the housing
2
, and a pin engaging member
3
through which the swivel pin
1
b
and the housing pin
2
a
are connected (see FIGS.
10
and
11
), is known.
In the pin engaging member
3
, two holes
4
are formed at a distance of e and the swivel pin
1
b
and the housing pin
2
a
are inserted into the holes
4
respectively in order to form the mechanism preventing rotation. In this mechanism preventing rotation, a crank
5
having an eccentricity distance &rgr; which is the same as the distance e is combined with a bearing
6
at the side of the swiveling scroll
1
, then, a quadric link L as shown in
FIG. 11
is formed, so that only rotation is prevented without preventing its revolution in the swiveling scroll
1
.
The mechanism preventing rotation makes it possible to decrease a number of components and thus simplify the mechanism in comparison with a mechanism preventing rotation with a conventional Oldham ring or ball coupling, so that the mechanism preventing rotation can have advantages of miniaturization and lightening of the mechanism. Furthermore, the pin engaging member
3
and the like composing the mechanism preventing rotation can be easily prepared, therefore, cost can be reduced.
In the mechanism preventing rotation, since a relative distance between the swivel pin
1
b
and the housing pin
2
a
maintains the constant value (=e), a swivel diameter of the swiveling scroll
1
also keeps a constant value. Accordingly, if there is an engaging position error in the engagement of the swiveling scroll
1
and a stationary scroll (not shown), a gap occurs by the position error and liquid leaks through the gap, so that a volumetric efficiency may decrease or disperse.
On the other hand, a mechanism preventing rotation having a ring-shape pin engaging member
7
of which a swivel pin
1
b
and a housing pin
2
a
are inserted into an inner space portion
7
a,
as shown a principal portion thereof in
FIGS. 12 and 13
, is disclosed in Japanese Examined Patent Application, Second Publication, No. 6-68276 (Kokoku).
In this composition, variation of the relative distance between the swivel pin
1
b
and the housing pin
2
a
is accepted, so that the swivel diameter of the swiveling scroll
1
is variable and the engaging position error in the engagement between both scrolls can be offset.
However, the mechanism preventing rotation has the pin engaging member
7
which rolls according to the revolutional swivel movement of the swiveling scroll
1
and the swivel pin
1
b
and the housing pin
2
a
rolling-contact with the inside surface of the pin engaging member
7
, and therefore, this mechanism preventing rotation has the disadvantage that each of these pins
1
b
and
2
a,
and the pin engaging member
7
has short fatigue life.
Moreover, by reason of design, when the pin diameters of the swivel pin
1
b
and the housing pin
2
a
are changed, a difference occurs among each relative rolling velocity of the pin
1
b,
2
a,
and the pin engaging member
7
in the rolling contact, and accordingly, a relative slip occurs between one pin
1
b
(or
2
a
) and the pin engaging member
7
, and thus partial wearing may occur. Therefore, there is a disadvantage that it is difficult to respond to design changes.
SUMMARY OF THE INVENTION
The present invention was achieved in view of the above circumstances, and the object of the present invention is to provide a swiveling scroll having variable swivel diameter in order to effectively prevent liquid from leaking.
Furthermore, another object of the present invention is to provide a mechanism for preventing rotation having long life and easily corresponding to a design change.
In order to solve the above-described problems, the present invention employs the following construction.
The present invention provides a scroll type fluid machine comprising a stationary scroll and a swiveling scroll each containing an involute wrap at a first end surface of an end plate in a standing state, wherein the stationary scroll and the swiveling scroll are mutually decentered, their phases are shifted, shifted scrolls are engaged with each other, and engaged scrolls are arranged in a housing, and the swiveling scroll performs a revolution swivel movement about the stationary scroll engaged in the housing; comprising a mechanism preventing rotation having: a swivel side pin projecting from a second end surface of the end plate of the swiveling scroll, a stationary side pin projecting from the housing to the second end surface side, a pin engaging member sliding these swivel side pin and stationary side pin at sliding contact portion with admitting radial variation and controlling maximum variation.
In the scroll type fluid machine, since the engaging position error between both scrolls is offset and the radial maximum displacement is limited by the stationary side pin and the swivel side pin slide-contacting the sliding contact portion of the pin engaging member, the fatigue life of each of the pin engaging member and both pins is longer than that of those members if they were rolling-contacted.
Moreover, by sliding-contacting both pins and the pin engaging member, a lubrication oil film can support a load as a sliding bearing, and even if outside diameters of both pins cannot have the same size, localized relative rolling cannot occur as in the case of rolling contact, therefore, it is partial wear cannot occur.
Furthermore, the scroll type fluid machine may have the pin engaging member comprising holes in which the swivel side pin and the stationary side pin is each engaged with free movement and inner surfaces of the holes are defined as the sliding contact portions.
In the above constructions, the swivel side pin and the stationary side pin is each inserted in the holes formed in the pin engaging member with free movement and relative interval variation between these pins in the holes is admitted, so that a swivel diameter can be variable as a matter of course, since these pins and the inner surfaces of the pin engaging members sliding-contact while the swiveling scroll performs the revolution swivel movement, as similar to the above, a load supported by lubrication oil film, longer fatigue life, and prevention of partial wear can be actualized.
The scroll type fluid machine may have the pin engaging member comprising a narrow hole in which the swivel side pin and the stationary side pin is each engaged at an interval with free movement and inner surfaces of the hole is defined as the sliding contact portion.
This narrow hole is obtained, for example, by connecting tangents with each hole enclosing the swivel side pin and the stationary side pin without crossing each other.
In these constructions, the swivel side pin performs circular motion with the swivel diameter that varies within the predetermined range to the predetermined swivel diameter around the stationary side pin. The inner surface of the pin engaging member engages a radial motion by sliding-contacting the outer surface of both pins. In the inner surface of the pin engaging member, the part to the outside of the centers of the pins engaged in the narrow hole with free movement effectively performs this engagement.
Therefore, the inner surface of the pin engaging membe

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