U.S. patent application number 13/377771 was filed with the patent office on 2012-04-12 for scroll fluid machine.
This patent application is currently assigned to Sanden Corporation. Invention is credited to Jiro Iizuka, Kiyoshi Terauchi.
Application Number | 20120087818 13/377771 |
Document ID | / |
Family ID | 43308905 |
Filed Date | 2012-04-12 |
United States Patent
Application |
20120087818 |
Kind Code |
A1 |
Iizuka; Jiro ; et
al. |
April 12, 2012 |
Scroll Fluid Machine
Abstract
Disclosed is a scroll fluid machine configured from inexpensive
materials and provided with a rotation prevention mechanism with
excellent durability. In the scroll fluid machine, a fixed scroll,
the spiral body of which has been vertically disposed on one end
surface of an endplate, and a movable scroll, the spiral body of
which has been vertically disposed on one end surface of the
endplate, are arranged eccentrically to and out of phase with each
other such that the spiral bodies engage with each other and the
movable scroll turns relative to the fixed scroll. The scroll fluid
machine is characterized by being provided with a rotation
prevention mechanism comprising a movable-side pin that protrudes
from the other surface of the endplate of the movable scroll, a
fixed-side pin that protrudes from the housing side towards the
other surface of the endplate of the movable scroll, and a rotation
prevention member held from both sides by the movable-side pin and
the fixed-side pin.
Inventors: |
Iizuka; Jiro; (Gunma,
JP) ; Terauchi; Kiyoshi; (Gunma, JP) |
Assignee: |
Sanden Corporation
Gunma
JP
|
Family ID: |
43308905 |
Appl. No.: |
13/377771 |
Filed: |
June 9, 2010 |
PCT Filed: |
June 9, 2010 |
PCT NO: |
PCT/JP2010/059753 |
371 Date: |
December 12, 2011 |
Current U.S.
Class: |
418/55.1 |
Current CPC
Class: |
F01C 1/0215 20130101;
F01C 17/06 20130101; F04C 18/0253 20130101; F01C 17/063 20130101;
F01C 1/0246 20130101 |
Class at
Publication: |
418/55.1 |
International
Class: |
F04C 18/00 20060101
F04C018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 11, 2009 |
JP |
2009-140211 |
Claims
1. A scroll-type fluid machine, wherein a fixed scroll, which is
provided with a scroll body standing on an end surface of an end
plate, and a movable scroll, which is provided with a scroll body
standing on an end surface of an end plate, are provided
eccentrically out of phase by engaging scroll bodies with each
other so that said movable scroll is rotated relative to said fixed
scroll, wherein the machine comprises a rotation-preventing
mechanism comprising a movable-side pin protruding from another end
surface of said end plate of said movable scroll, a fixed-side pin
protruding from a housing-side toward another side of said end
surface of said end plate of said fixed scroll, and a
rotation-preventing member which is supported between both sides of
said movable-side pin and said fixed-side pin.
2. The scroll-type fluid machine according to claim 1, wherein said
rotation-preventing member has a movable-side depressed part which
engages said movable-side pin and a fixed-side depressed part which
engages said fixed-side pin.
3. The scroll-type fluid machine according to claim 2, wherein at
least one of said movable-side depressed part and said fixed-side
depressed part is formed as a part of a hole in said
rotation-preventing member.
4. The scroll-type fluid machine according to claim 2, wherein
either or both depths of said movable-side depressed part and said
fixed-side depressed part
5. The scroll-type fluid machine according to claim 4, wherein a
difference between said minimum value (Lor) of said center distance
(L) between said movable-side pin and said fixed-side pin, and said
swing radius (AOR) of said movable scroll is within 0.1 mm.
6. The scroll-type fluid machine according to claim 4, wherein a
difference between said minimum value (Lor) of said center distance
(L) between said movable-side pin and said fixed-side pin, and said
swing radius (AOR) of said movable scroll is set smaller than a
difference between a depth (B1) of said movable-side depressed part
and an axial radius (R1) of said movable-side pin.
7. The scroll-type fluid machine according to claim 4, wherein a
difference between said minimum value (Lor) of said center distance
(L) between said movable-side pin and said fixed-side pin, and said
swing radius (AOR) of said movable scroll is set smaller than a
difference between a depth (B2) of said fixed-side depressed part
and an axial radius (R2) of said fixed-side pin.
8. The scroll-type fluid machine according to claim 1, wherein
movable-side pins and fixed-side pins are plurally placed along
circumferences of placement-pitch circles having placement-pitch
angles (Ap), which are equal to each other, and diameters, which
are equal to each other.
9. The scroll-type fluid machine according to claim 8, wherein said
fixed-side pin and said movable-side pin are placed out of phase
with each other by a predetermined angle (.theta.) satisfying
Formula 1 toward a direction to eliminate a distortion of said
movable scroll relative to said fixed scroll.
.theta..ltoreq.2tan-1[(AOR-Lor)/Dp] [Formula 1]
10. The scroll-type fluid machine according to claim 1, wherein
said fixed scroll and said movable scroll are assembled so that an
initial value of a center distance (L) between said fixed-side pin
and said movable-side pin is set to a minimum value (Lor) for one
rotation-preventing member while said initial value of said center
distance (L) between said fixed-side pin and said movable-side pin
is set to a swing radius (AOR) of said movable scroll for another
rotation-preventing member.
11. The scroll-type fluid machine according to claim 1, wherein a
thickness of said rotation-preventing member in an axial direction
is set to a maximum value under a condition where an axial interval
between said movable scroll and a housing is kept equal to or
greater than an oil film thickness as not interfering within a
dimensional tolerance.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a scroll-type fluid
machine, and specifically relates to a rotation-preventing
mechanism of a movable scroll which is provided to constitute a
compression mechanism of a scroll-type fluid machine.
BACKGROUND ART OF THE INVENTION
[0002] A compression mechanism and an expansion mechanism of
scroll-type compressors or expanders generally consist of a
combination of fixed scroll and movable scroll. The movable scroll
is provided so as to freely revolve but not to rotate, relative to
the fixed scroll. Some kinds of mechanisms are known as a
rotation-preventing mechanism which makes it impossible to rotate a
movable scroll.
[0003] For example, Patent document 1 discloses a scroll-type fluid
machine where a swing pin, which is provided on a swing scroll as
protruding, and a housing pin, which is provided on a fixed scroll
as protruding, are contacted slidably with inner peripheral
surfaces of 2 holes which are formed in a protrusion binding member
for regulating a relative distance between both pins, in order to
prevent the swing scroll from rotating.
[0004] In addition, Patent document 2 discloses a scroll-type
compressor where a movable pin member, which is provided on a
movable scroll as protruding, and a fixed pin member, which is
provided on a fixed scroll as protruding, are engaged to be
contacted in pairs, in order to prevent the movable scroll from
rotating.
Prior Art Documents
Patent Documents
Patent Document 1: JP-4088392-B
Patent Document 2: JP-3337831-B
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] In the rotation-preventing mechanism of the scroll-type
fluid machine disclosed by Patent document 1, the protrusion
binding member rotates as sweeping a larger area because the swing
radius is held at the side of the swing pin of the protrusion
binding member, and therefore a thrust bearing cannot be easily
extended. In addition, because the protrusion binding member is
subject to tensile stress, materials, such as various resins, light
metals and sintered materials, which are fragile with low tension
strength cannot be utilized, and therefore the cost has not been
able to reduce. Further, a complicated work for fitting the pin
into the hole is required when the swing scroll and the fixed
scroll are assembled. Therefore it has been difficult to improve
the productivity, as well as to form a flow path for lubricating
oil between the pin and the protrusion binding member.
[0006] Furthermore, in the rotation-preventing mechanism of the
scroll-type compressor disclosed by Patent document 2, because
surface pressure increases because of contact between the movable
pin member and the fixed pin member, oil film tends to be made
imperfect so as to cause abrasion of members.
[0007] Accordingly, an object of the present invention is to
provide a scroll-type fluid machine which is made by inexpensive
members and which is provided with a rotation-preventing mechanism
having excellent durability.
Means for Solving the Problems
[0008] To achieve the above-described object, a scroll-type fluid
machine according to the present invention is a scroll-type fluid
machine, wherein a fixed scroll, which is provided with a scroll
body standing on an end surface of an end plate, and a movable
scroll, which is provided with a scroll body standing on an end
surface of an end plate, are provided eccentrically out of phase by
engaging scroll bodies with each other so that the movable scroll
is rotated relative to the fixed scroll, characterized in that a
rotation-preventing mechanism, which comprises a movable-side pin
protruding from another end surface of the end plate of the movable
scroll, a fixed-side pin protruding from a housing-side toward
another side of the end surface of the end plate of the fixed
scroll, and a rotation-preventing member which is supported between
both sides of the movable-side pin and the fixed-side pin, is
provided.
[0009] Because a fixed-side pin and a movable-side pin support a
rotation-preventing member from both sides in a scroll-type fluid
machine, the rotation-preventing member is not subject to tensile
stress but is only subject to compressive stress basically, so that
the rotation-preventing member can be manufactured at a low cost by
sintering, etc. In addition, the rotation-preventing member can be
formed as extremely small, so as to suppress centrifugal force and
reduce noise generated by device vibration.
[0010] In the scroll-type fluid machine according to the present
invention, it is preferable that the rotation-preventing member has
a movable-side depressed part which engages the movable-side pin,
and has a fixed-side depressed part which engages the fixed-side
pin. Because the rotation-preventing member is not subject to
tensile stress, it becomes unnecessary that the movable-side pin
and the fixed-side pin are holes. Therefore, the
rotation-preventing member can be downsized and lightweight, by
forming the rotation-preventing member having a depressed part at
least.
[0011] In the scroll-type fluid machine according to the present
invention, it is possible that at least one of the movable-side
depressed part and the fixed-side depressed part is formed as a
part of a hole in the rotation-preventing member. When at least one
of the depressed parts is formed as a part of the hole, simplified
can be a working to fit the rotation-preventing member with the
movable-side depressed part or the fixed-side depressed part.
[0012] In the scroll-type fluid machine according to the present
invention, it is preferable that either or both depths of the
movable-side depressed part and the fixed-side depressed part are
set as making minimum value (Lor) of a center distance (L) between
the movable-side pin and the fixed-side pin smaller than a swing
radius (AOR) of the movable scroll. When the depths of the
depressed parts are set as satisfying the formula (Lor<AOR),
operations such as engaging and sliding of the pins can be smoothly
performed even if the accuracy of component parts is somewhat bad
and sizes have some errors. Therefore, the rotation-preventing
mechanism is ensured in durability as preventing excessive load
generation, even when troubles, such as liquid compression and
foreign substance bite, are caused. Further, it is preferable that
a difference between the minimum value (Lor) of the center distance
(L) between the movable-side pin and the fixed-side pin, and the
swing radius (AOR) of the movable scroll is within 0.1 mm. Namely,
when the rotation-preventing mechanism is designed to satisfy the
magnitude relation (Lor<AOR.ltoreq.Lor+0.1 mm), the scroll can
be smoothly operated without being affected by dimensional
precision of component parts. Therefore a low-noise scroll-type
fluid machine, which is excellent in durability even in an abnormal
condition, can be achieved.
[0013] In the scroll-type fluid machine according to the present
invention, it is preferable that a difference between the minimum
value (Lor) of the center distance (L) between the movable-side pin
and the fixed-side pin, and the swing radius (AOR) of the movable
scroll is set smaller than a difference between a depth (B1) of the
movable-side depressed part and an axial radius (R1) of the
movable-side pin. Namely, when the rotation-preventing member is
designed to satisfy the magnitude relation (AOR-Lor.ltoreq.B1-R1),
the rotation-preventing member can be surely supported between the
movable-side pin and the fixed-side pin thereby. In addition,
because the depth of the movable-side depressed part becomes
sufficiently greater than the axial radius of the movable-side pin,
the contact area between the movable-side pin and the movable-side
depressed part can be set wider, so as to suppress surface pressure
as preventing oil film from being made imperfect.
[0014] In addition, the fixed side is similar to the movable side.
Namely in the scroll-type fluid machine according to the present
invention, it is preferable that a difference between the minimum
value (Lor) of the center distance (L) between the movable-side pin
and the fixed-side pin, and the swing radius (AOR) of the movable
scroll is set smaller than a difference between a depth (B2) of the
fixed-side depressed part and an axial radius (R2) of the
fixed-side pin. Namely, when the rotation-preventing member is
designed to satisfy the magnitude relation (AOR-Lor.ltoreq.B2-R2),
the rotation-preventing member can be surely supported between the
movable-side pin and the fixed-side pin. In addition, because the
depth of the fixed-side depressed part becomes sufficiently greater
than the axial radius of the fixed-side pin, the contact area
between the fixed-side pin and the fixed-side depressed part can be
set wider, so as to suppress surface pressure as preventing oil
film from being made imperfect.
[0015] In the scroll-type fluid machine of the present invention,
it is preferable that movable-side pins and fixed-side pins are
plurally placed along circumferences of placement-pitch circles
having placement-pitch angles (Ap), which are equal to each other,
and diameters, which are equal to each other. When a pair of
rotation-preventing elements composed of the movable-side pin, the
fixed-side pin and the rotation-preventing member is provided on
circumferences along circumferences of the scrolls, the movable
scroll can be effectively and smoothly prevented from rotating.
Particularly, the movable scroll can be further effectively
prevented from rotating when the fixed-side pin and the
movable-side pin are placed out of phase with each other by a
predetermined angle (.theta.) satisfying Formula 1 toward a
direction to eliminate a distortion of the movable scroll relative
to the fixed scroll. Actually in scroll-type fluid machine, there
is a tolerance to each set of the fixed-side pin, the movable-side
pin and the rotation-preventing member, so .theta. is determined so
as not to interfere, as considering the tolerance.
.theta..ltoreq.2tan.sup.-1[(AOR-Lor)/Dp] [Formula 1]
[0016] In the scroll-type fluid machine according to the present
invention, it is preferable that the fixed scroll and the movable
scroll are assembled so that an initial value of a center distance
(L) between the fixed-side pin and the movable-side pin is set to a
minimum value (Lor) for one rotation-preventing member while the
initial value of the center distance (L) between the fixed-side pin
and the movable-side pin is set to a swing radius (AOR) of the
movable scroll for another rotation-preventing member. The
supported condition of the rotation-preventing member supported
between the movable-side pin and the fixed-side pin thereby
progresses as being passed on to adjacent rotation-preventing
element with swing of the movable scroll, so as to repeat a cycle.
As described above, the fixed scroll and the movable scroll are
assembled in such a condition that the initial value of the center
distance (L) between the fixed-side pin and the movable-side pin is
set to the minimum value (Lor) for one rotation-preventing member
while the initial value of the center distance (L) between the
fixed-side pin and the movable-side pin is set equal to the swing
radius (AOR) of the movable scroll for another rotation-preventing
member. The movable scroll starts to rotate from such an initial
condition, so that the rotation-preventing member is smoothly
transited between supported conditions. And, as a result, the
movable scroll can be smoothly rotated.
[0017] In the scroll-type fluid machine according to the present
invention, it is preferable that a thickness of the
rotation-preventing member in an axial direction is set to a
maximum value under a condition where an axial interval between the
movable scroll and a housing is kept equal to or greater than an
oil film thickness as not interfering within a dimensional
tolerance. Thus the scroll-type fluid machine according to the
present invention makes it possible that the rotation-preventing
member is easily enhanced in durability because the axial thickness
of the rotation-preventing member can be maximized, as far as the
movable scroll swings without any problem.
EFFECT ACCORDING TO THE INVENTION
[0018] Thus a scroll-type fluid machine according to the present
invention makes it possible that a rotation-preventing member is
manufactured by sintering, etc. as reducing a cost because the
rotation-preventing member has a configuration which is subject
only to compressive stress. Further, the rotation-preventing member
can be designed to be extremely small, so as to achieve a
scroll-type fluid machine which generates little centrifugal force
and which has been improved in vibration noise. Furthermore, a
counterweight can be easily ensured in weight because the
rotation-preventing member is downsized so as to extend an area in
which the rotation-preventing member does not interfere.
[0019] In the scroll-type fluid machine according to the present
invention, the contact area of the rotation-preventing member to
the movable-side pin or the fixed-side pin can be easily broaden,
so that a durable rotation-preventing mechanism which is suppressed
from imperfect oil film with low surface pressure can be easily
achieved. Further, when the movable-side depressed part of the
rotation-preventing member to engage with the movable-side pin is
formed as opening outward, the work to assemble the movable scroll
to the fixed scroll can be simplified.
[0020] In the scroll-type fluid machine according to the present
invention, because the minimum swing radius is determined only by a
structure of the rotation-preventing mechanism, a protrusion of the
eccentric bush can be abolished. Furthermore, when the dimension of
the rotation-preventing member is designed within a predetermined
range, achieved can be a scroll-type fluid machine which can
operate smoothly without being affected by dimensional accuracy of
component parts and which is ensured to be durable without
generating excessive load even when troubles, such as liquid
compression and foreign substance bite, are caused.
BRIEF EXPLANATION OF THE DRAWINGS
[0021] FIG. 1 is a longitudinal section view showing a compressor
according to an embodiment of the present invention.
[0022] FIG. 2 is a cross section view showing a rotation-preventing
mechanism of the compressor in FIG. 1.
[0023] FIG. 3 is an explanation diagram for explaining discordant
placement angle of the movable scroll, which is caused by rotation
power applied to the movable scroll in FIG. 1.
[0024] FIG. 4 is a plan view showing a rotation-preventing member
for preventing a movable scroll in FIG. 1 from rotating, where (A)
is an example in which both depressed parts are not a part of a
hole, and (B) is an example in which one of depressed parts is a
part of a hole.
[0025] FIG. 5 is a cross section view showing a rotation-preventing
mechanism of a scroll-type compressor according to another
embodiment of the present invention.
[0026] FIG. 6 is a cross section view showing a rotation-preventing
mechanism of a scroll-type compressor according to yet another
embodiment of the present invention.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0027] Hereinafter, desirable embodiments of the present invention
will be explained as referring to figures.
[0028] FIG. 1 shows a whole of a scroll-type compressor 1 according
to an embodiment of the present invention. In FIG. 1, compression
mechanism 2 comprises fixed scroll 3 consisting of a scroll body
and movable scroll 4 consisting of a scroll body and end plate 5.
Movable scroll 4 is swung relative to fixed scroll 3 as being
prevented from rotating by rotation-preventing elements 36
comprised of rotation-preventing members 31, fixed-side pins 34 and
movable-side pins 35. Main shaft 8 (rotational axis) is driven to
rotate while compressor 1 operates, and a rotational motion of main
shaft 8 is converted into a swing motion of movable scroll 4,
through eccentric pin 9 provided at one side of main shaft 8 and
through eccentric bush 10 rotatably engaged therewith. The
refrigerant sucked as fluid to be compressed is led to compression
mechanism 2 so as to be compressed, and is delivered outside
compressor 1 from casing 6 through discharge hole 13 and discharge
chamber 14.
[0029] FIG. 2 is a cross section view showing a rotation-preventing
mechanism of compressor 1 in FIG. 1. Inside compressor housing 6,
fixed scroll 3 and movable scroll 4 are assembled to be engaged by
scroll bodies with each other as forming compression mechanism 2.
Movable scroll 4 swings by a predetermined swing radius (AOR),
around the center axis of fixed scroll 3 which is always standing
still. Accompanying such a swing motion of movable scroll 4, fluid,
such as refrigerant, to be compressed is compressed.
[0030] Movable scroll 4 is prevented from rotating by movable-side
pins 35 (35a-35d) protruding on the surface which is opposite to
fixed scroll 3 of end plate 5 of movable scroll 4, fixed-side pins
34 (34a-34d) protruding toward movable-side pins 35 (35a-35d) in
housing 6, and rotation-preventing members 31 (31a-31d).
Rotation-preventing members 31 (31a-31d) of which planar shapes are
formed in a schematic H-shape are provided with fixed-side
depressed parts 32 (32a-32d) engaging fixed-side pins 34 (34a-34d)
and with movable-side depressed parts 33 (33a-33d) engaging
movable-side pins 35 (35a-35d), and are supported between
movable-side pins 35 (35a-35d) and fixed-side pins 34 (34a-34d)
thereby.
[0031] In this embodiment, fixed-side pins 34 and movable-side pins
35 are placed on end plate 5 of movable scroll 4 along
placement-pitch circles, which have placement-pitch angles of 90
degrees each and diameters (Dp) which are equal to each other. Thus
placed fixed-side pins 34 and movable-side pins 35 constitute
rotation-preventing elements 36 (36a-36d) together with
rotation-preventing members 31 supported between them. Such
combinations of rotation-preventing elements 36 constitute
rotation-preventing mechanism of movable scroll 4.
[0032] In this embodiment, the distance between fixed-side pin 34
and movable-side pin 35 in one rotation-preventing element 36 is
not completely constant but is provided with some looseness. For
example, some gaps are formed between movable-side pins 35b-35d and
rotation-preventing members 31b-31d, as shown in FIG. 2.
Specifically the distance between fixed-side pin 34c and
movable-side pin 35c is comparatively great. In contrast, as to
fixed-side pin 34a or movable-side pin 35a, there is no gap between
it and rotation-preventing member 31a. Thus, the depth (B) of
rotation-preventing member 31 is determined appropriately, so as to
determine the minimum value (Lor) of the center distance (L)
between fixed-side pin 34 and movable-side pin 35. Such a center
distance (L) between fixed-side pin 34 and movable-side pin 35 is
preferably set as being provided with some looseness as described
above. Specifically, the depth (B) of rotation-preventing member 31
is preferably designed as making the minimum value (Lor) of the
center distance (L) smaller than the swing radius (AOR) of movable
scroll 4. However, movable scroll 4 cannot swing smoothly if the
difference between Lor and AOR is too big. Therefore the difference
is preferably within 0.1 mm.
[0033] Further, as shown in FIG. 2, it is preferable that fixed
scroll 3 and movable scroll 4 are assembled in such an initial
condition that the value of the center distance (L) is set to the
minimum value (Lor) for rotation-preventing element 36a and is set
equal to the swing radius (AOR) of movable scroll 4 for
rotation-preventing element 36c located the furthest from
rotation-preventing member 36a. If the looseness of the center
distance (L) is scattered over rotation-preventing elements 36a-36d
in an initial condition, the looseness of the center distance (L)
assumed by the depth (B) of rotation-preventing member 31 may not
work during swing motion of movability scroll 4 sufficiently.
Accordingly, it is preferable to assemble them as making angle
.alpha. which satisfies Formula 2, between a line segment
(length=Dp) extending from movable-side pin 35a to movable-side pin
35c and another line segment (length=Dp) extending from fixed-side
pin 34a to fixed-side pin 34c. Movable-side pins 35a-35d and
fixed-side pins 34a-34d are placed as satisfying such a relational
formula, so that the cycle of supporting conditions of
rotation-preventing members 31a-31d is smoothly progressed.
Besides, because rotation-preventing member 31 of this embodiment
can be easily made extremely compact, counterweight 37, even if it
is comparatively large, is unlikely to interfere
rotation-preventing member 31.
tan .alpha.=(AOR-Lor)/Dp [Formula 2]
[0034] In Formula 2, angle .alpha. is a small angle such as being
less than 0.2 degrees. When compressor 1 is operating, movable
scroll 4 is subject to a rotation power. Utilizing this rotation
power, fixed-side pin 34 and movable-side pin 35 support
rotation-preventing member 32 therebetween at one or more places
each on the circumference of each placement-pitch circle so as to
prevent movable scroll 4 from rotating. Under such a rotation
power, fixed-side pin 34 and movable-side pin 35 are placed out of
phase with each other by a predetermined angle (.theta.) toward a
direction to eliminate a distortion of movable scroll 4 relative to
fixed scroll 3. Such a condition will be explained by referring to
FIG. 3.
[0035] FIG. 3 is an explanation diagram for explaining discordant
placement angle of the movable scroll, which is caused by rotation
power applied to the movable scroll in FIG. 1. When the scroll wall
of movable scroll 4 swings as contacting the scroll wall of fixed
scroll 3 while movable scroll 4 is prevented from rotating, movable
scroll 4 is reciprocated with the amplitude equal to the swing
radius (AOR) in axis-Y direction. In this case, the distance from
the center O of placement-pitch circle 38 of movable-side pin 35 to
the center of another placement-pitch circle of fixed-side pin 34
is not less than the minimum value (Lor) of the center distance (L)
between fixed-side pin 34 and movable-side pin 35 because of the
presence of rotation-preventing members 31a-31d. The
placement-pitch circle of fixed-side pin 34 has approximately the
same diameter (Dp) of the placement-pitch circle 38 of movable-side
pin 35. The condition to be satisfied by the predetermined angle
(.theta.) by which movable scroll 4 rotates under the rotation
power applied to movable scroll 4 is as shown in Formula 1. Here
the predetermined angle (.theta.) links to angle .alpha. in Formula
2 by the relation between a central angle and an inscribed angle,
and therefore the relation .theta.=2.alpha. is satisfied obvious
from FIG. 3.
.theta..ltoreq.tan.sup.-1[(AOR-Lor)/Dp] [Formula 1]
[0036] FIG. 4 is a plan view showing rotation-preventing member 31
for preventing movable scroll 4 in FIG. 1 from rotating, where (A)
is an example in which both fixed-side depressed part 32 and
movable-side depressed part 33 are not a part of a hole, and (B) is
an example in which only movable-side depressed part 33 is a part
of a hole. As shown in FIG. 4 (A), because rotation-preventing
member 31 is not subject to tensile stress in this embodiment,
rotation-preventing member 31 can be supported between fixed-side
pin 34 and movable-side pin 35 even if both ends of depressed parts
of fixed-side depressed part 32 and movable-side depressed part 33
are open. Specifically the depth (B) of the depressed part is set
greater than the axial radius (R) of fixed-side pin 34 or
movable-side pin 35, so that rotation-preventing member 31 is
further surely supported between fixed-side pin 34 and movable-side
pin 35 thereby. Further, when the difference between the minimum
value (Lor) of the center distance (L) and the swing radius (AOR)
of movable scroll 4 is set smaller than the difference between the
depth (B1) of movable-side depressed part 33 and the axial radius
(R1) of movable-side pin 35, movable-side pin 35 can be more surely
engaged with movable-side depressed part 33 of rotation-preventing
member 31 while movable scroll 4 swings. The fixed side is similar
to the movable side. When the difference between the minimum value
(Lor) of the center distance (L) and the swing radius (AOR) of
movable scroll 4 is set smaller than the difference between the
depth (B2) of fixed-side depressed part 32 and the axial radius
(R2) of fixed-side pin 34, fixed-side pin 34 can be more surely
engaged with fixed-side depressed part 32 of rotation-preventing
member 31 while movable scroll 4 swings.
[0037] Further, rotation-preventing member 41 can be provided with
a hole by closing both depressed parts of fixed-side depressed part
32 as shown in FIG. 4 (B). Thus, if either fixed-side depressed
part 34 or movable-side depressed part 33 becomes a part of a hole,
fixed-side pin 34 can be put through the hole when movable scroll 4
is assembled together with fixed scroll 3, so that the assembling
work is simplified.
[0038] FIG. 5 is a cross section view showing a rotation-preventing
mechanism of a scroll-type compressor according to another
embodiment of the present invention, where rotation-preventing
members 31 (31a-31d) in FIG. 2 have been replaced by rotation
members 41 (41a-41d) in FIG. 4 (B). The other aspects are the same
as FIG. 2, so the explanation of the embodiment is omitted as
giving the same symbols. When fixed-side depressed part 32 is a
part of the hole, a scroll-type compressor can be improved in
assembly easiness.
[0039] FIG. 6 is a cross section view showing a rotation-preventing
mechanism of a scroll-type compressor according to yet another
embodiment of the present invention. Rotation-preventing members 51
(51a-51d) in this embodiment are formed in a modified shape of
rotation-preventing member 41 shown in FIG. 4(B), where fixed-side
depressed part 32 is replaced by the movable-side depressed part.
Namely, just like being opposite to rotation-preventing member 41
in FIG. 4(B), both ends of a depressed part of fixed-side depressed
part 32 are opened while both ends of a depressed part of
movable-side depressed part 33 are closed. Thus, even if
movable-side depressed part 33 is a part of a hole, the assembly
easiness of a scroll-type compressor can be improved similarly to a
case where fixed-side depressed part 32 is a part of a hole.
INDUSTRIAL APPLICATIONS OF THE INVENTION
[0040] A scroll-type compressor according to the present invention
is applicable to all types of scroll-type compressor having a
rotation-preventing mechanism with a rotation-preventing
member.
EXPLANATION OF SYMBOLS
[0041] 1: compressor [0042] 2: compression mechanism [0043] 3:
fixed scroll [0044] 4: movable scroll [0045] 5: end plate [0046] 6:
casing [0047] 7: housing [0048] 8: main shaft [0049] 9: eccentric
pin [0050] 10: eccentric bush [0051] 13: discharge hole [0052] 14:
discharge chamber [0053] 31, 41, 51, 31a, 31b, 31c, 31d:
rotation-preventing member [0054] 32: fixed-side depressed part
[0055] 33: movable-side depressed part [0056] 34, 34a, 34b, 34c, a
34d: fixed-side pin [0057] 35, 35a, 35b, 35c, 35d: movable-side pin
[0058] 36, 36a, 36b, 36c, 36d: rotation-preventing element [0059]
37: counterweight [0060] 38: placement-pitch circle
* * * * *