AU2019225271B2

AU2019225271B2 - Scroll fluid machine

Info

Publication number: AU2019225271B2
Application number: AU2019225271A
Authority: AU
Inventors: Takahide Ito; Yoshiyuki Kimata; Hajime Sato
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2018-02-21
Filing date: 2019-01-11
Publication date: 2022-01-27
Anticipated expiration: 2039-01-11
Also published as: CN111742143A; JP2019143552A; AU2019225271A1; EP3754198A4; JP6679633B2; CN111742143B; WO2019163323A1; EP3754198A1

Abstract

In a scroll compressor (1) provided with a fixed scroll (3) and an orbiting scroll (5), an inclined section is provided in which the facing-surface distance (L) between an end plate (3a) and an end plate (5a) that face each other decreases continuously from the outer peripheral side towards the inner peripheral side. In grooves formed in the tooth tip of walls (3b, 5b), tip seals are provided that seal a fluid by contacting the opposite tooth bottom. Defining ρ as the turning radius of the orbiting scroll 5 and φ as the incline in the swirl direction of the inclined section, the amount of change in the tip clearance (ΔT) is set to ΔT = 2ρ×tanφ, and the amount of change in the tip clearance (ΔT) is less than or equal to 50% of the height dimension of the tip seal.

Description

[DESCRIPTION]

[Title of Invention]

SCROLL FLUID MACHINE

[Technical Field]

[0001]

The present invention relates to a scroll fluid machine.

[Background Art]

[0002]

The discussion of the background to the invention that

follows is intended to facilitate an understanding of the

invention. However, it should be appreciated that the

discussion is not an acknowledgement or admission that any

aspect of the discussion was part of the common general

knowledge as at the priority date of the application.

[0002a]

Generally, there is known a scroll fluid machine in which

a fixed scroll member and an orbiting scroll member provided

with respective spiral walls on respective end plates are

engaged and revolved to compress or expand fluid.

[0003]

As such a scroll fluid machine, a so-called stepped

scroll compressor disclosed in PTL 1 is known. In this

stepped scroll compressor, respective step sections are la provided at positions along the spiral directions of tooth tip surfaces and tooth bottom surfaces of spiral walls of a fixed scroll and an orbiting scroll, and the height of the outer circumferential side of the wall is made higher than the height of the inner circumferential side of the wall with each step section as a boundary. The stepped scroll compressor performs compression not only in the circumferential direction of the walls, but also in the height direction (three dimensional compression), and therefore it is possible to increase displacement and increase compressor capacity compared to a general scroll compressor with no step section

(two-dimensional compression).

[Citation List]

[Patent Literature]

[0004]

[PTL 1] Japanese Unexamined Patent Application, Publication

No. 2015-55173

[Summary of Invention]

[Technical Problem]

[0005]

However, the stepped scroll compressor has a problem that

fluid leakage at the step sections is large. Further, there

is a problem that stress is concentrated on root portions of

the step sections, and strength is reduced.

[0006]

To cope with the above, the inventors are considering

providing continuous inclined sections in place of the step

sections provided on the walls and the end plates.

However, even when the inclined sections are provided, it

is not yet established what is a proper degree of inclination for each inclined section.

[0007]

The present invention has been made in view of such a

circumstance, and it is desirable to provide a scroll fluid

machine having inclined sections in a wall and an end plate

capable of effectively exhibiting performance.

[0008]

A scroll fluid machine according to an aspect of the

present invention is a scroll fluid machine comprising: a

first scroll member provided with a spiral first wall on a

first end plate; and a second scroll member that is provided

with a spiral second wall on a second end plate disposed so as

to face the first end plate, and that relatively revolves by

engagement between the second wall and the first wall, wherein

an inclined section that continuously reduces an inter-facing

surface distance between the first end plate and the second

end plate facing each other, from an outer circumferential

side toward an inner circumferential side of each of the first

wall and the second wall is provided, each of the inclined

sections is provided over a range of 1800 or more around a

spiral center, a groove section formed in a tooth tip of each

of the first wall and the second wall corresponding to the

inclined sections is provided with a tip seal that comes into

contact with a facing tooth bottom to seal fluid the tip seal being pressed from a back surface by compressed fluid entering the groove section while following a change of a tip clearance change amount AT due to orbiting movement, where an orbiting radius of the scroll member that orbits is denoted by p, and an inclination in a spiral direction of the inclined section is denoted by T, the tip clearance change amount AT is defined by an expression as follows:

AT = 2p x tan T, and

the tip clearance change amount AT is 50% or less of a

height dimension of the tip seal in a height direction of the

wall.

[00091

The inclined section that continuously reduces the inter

facing-surface distance between the first end plate and the

second end plate from the outer circumferential side toward

the inner circumferential side of each wall is provided, and

therefore fluid sucked from the outer circumferential side is

not only compressed by reduction of compression chambers in

accordance with the spiral shape of the wall, but also further

compressed by reduction of the inter-facing-surface distance

between the end plates, toward the inner circumferential side.

The inclined sections are provided, and therefore the tip

clearance between the tooth tip and the tooth bottom changes in accordance with orbiting movement. Where the orbiting radius of the scroll member that orbits is denoted by p, and the inclination in the spiral direction of the inclined section is denoted by T, the tip clearance change amount AT in accordance with this orbiting movement is obtained by the expression as follows:

AT = 2p x tan p.

The tip seal advances and retreats in the height

direction from the groove section by an amount in accordance

with this tip clearance change amount AT. Therefore, when the

tip clearance change amount AT is large, the tip seal may be

detached from the groove section.

To cope with the above, the tip clearance change amount

AT is made to be 50% or less of the height dimension of the

tip seal, so that drop of the tip seal is prevented.

More preferably, the tip clearance change amount AT is

made to be 20% of less of the height dimension of the tip

seal.

[0010]

A scroll fluid machine according to an aspect of the

present invention is a scroll fluid machine including: a first

scroll member provided with a spiral first wall on a first end

plate; and a second scroll member that is provided with a

spiral second wall on a second end plate disposed so as to

face the first end plate, and that relatively revolves by engagement between the second wall and the first wall, wherein an inclined section that continuously reduces an inter-facing surface distance between the first end plate and the second end plate facing each other, from an outer circumferential side toward an inner circumferential side of each of the first wall and the second wall is provided, each of the inclined sections is provided over a range of 1800 or more around a spiral center, where an orbiting radius of the scroll member that orbits is denoted by p, and an inclination in a spiral direction of the inclined section is denoted by T, a tip clearance change amount AT is defined by an expression as follows:

AT = 2p x tan T, and

a value obtained by dividing the tip clearance change

amount AT by a height of an outermost circumference of the

wall is 0.01 or less.

[0011]

The inclined section that continuously reduces the inter

facing-surface distance between the first end plate and the

second end plate from the outer circumferential side toward

the inner circumferential side of each wall is provided, and

therefore fluid sucked from the outer circumferential side is

not only compressed by reduction of compression chambers in

accordance with the spiral shape of the wall, but also further

compressed by reduction of the inter-facing-surface distance between the end plates, toward the inner circumferential side.

The inclined sections are provided, and therefore the tip

clearance between the tooth tip and the tooth bottom changes

in accordance with orbiting movement. Where the orbiting

radius of the scroll member that orbits is denoted by p, and

the inclination in the spiral direction of the inclined

section is denoted by T, the tip clearance change amount AT in

accordance with this orbiting movement is obtained by the

expression as follows:

AT = 2p x tan p.

An oil film seal by lubricating oil is formed between the

tooth tip and the tooth bottom. However, when the tip

clearance change amount AT is increased, the oil film seal

between the tooth tip and the tooth bottom may be broken, seal

performance of a compression chamber may be deteriorated, and

efficiency may be reduced.

As a result of keen examination by the present inventors,

it is found that when the value obtained by dividing the tip

clearance change amount AT by the height of the outermost

circumference of the wall is 0.01 or less, the oil film seal

is maintained, significant performance deterioration does not

appear, and expected efficiency can be maintained.

[0012]

A scroll fluid machine according to an aspect of the

present invention is a scroll fluid machine including: a first scroll member provided with a spiral first wall on a first end plate; and a second scroll member that is provided with a spiral second wall on a second end plate disposed so as to face the first end plate, and that relatively revolves by engagement between the second wall and the first wall, wherein an inclined section that continuously reduces an inter-facing surface distance between the first end plate and the second end plate facing each other, from an outer circumferential side toward an inner circumferential side of each of the first wall and the second wall is provided, each of the inclined sections is provided over a range of 1800 or more around a spiral center, and a tip clearance between a tooth tip of the wall and a tooth bottom of the end plate is set larger than a tip clearance reduction amount based on a torsion angle around a center of the scroll member due to an assembly error.

[0013]

The inclined section that continuously reduces the inter

facing-surface distance between the first end plate and the

second end plate from the outer circumferential side toward

the inner circumferential side of each wall is provided, and

therefore fluid sucked from the outer circumferential side is

not only compressed by reduction of compression chambers in

accordance with the spiral shape of the wall, but also further

compressed by reduction of the inter-facing-surface distance

between the end plates, toward the inner circumferential side.

In the scroll fluid machine, when the first scroll member

and the second scroll member are assembled, an assembly error

inevitably occurs due to dimensional accuracy of an Oldham

ring, or location accuracy of a centering pin or the like.

When the assembly error occurs, the scroll member is twisted

around the center, and the tip clearance between the tooth tip

and the tooth bottom of the inclined sections is reduced on

the basis of the torsion angle.

To cope with the above, the tip clearance between the

tooth tip and the tooth bottom is set larger than the tip

clearance reduction amount based on the torsion angle around

the center of the scroll member due to the assembly error, and

interference between the tooth tip and the tooth bottom is

avoided.

[Advantageous Effects of Invention]

[0014]

The tip clearance change amount AT (= 2p x tan T) is made

to be 50% or less of the height dimension of the tip seal, so

that it is possible to prevent drop of the tip seal.

Consequently, even when the wall and the end plate have the

inclined sections, it is possible to exhibit performance.

[0015]

The value obtained by dividing the tip clearance change

amount AT (= 2p x tan T) by the height of the outermost circumference of the wall is 0.01 or less, so that the oil film seal is maintained, significant performance deterioration does not appear, and expected efficiency can be maintained.

[0016]

The tip clearance between the tooth tip and the tooth

bottom is set larger than the tip clearance reduction amount

based on the torsion angle around the center of the scroll

member due to an assembly error, so that it is possible to

avoid interference between the tooth tip and the tooth bottom.

[0016a]

Where any or all of the terms "comprise", "comprises",

"comprised" or "comprising" are used in this specification

(including the claims) they are to be interpreted as

specifying the presence of the stated features, integers,

steps or components, but not precluding the presence of one or

more other features, integers, steps or components.

[Brief Description of Drawings]

[0017]

[Fig. 1A] Fig. 1A is a longitudinal sectional view

illustrating a fixed scroll and an orbiting scroll of a scroll

compressor according to one embodiment of the present

invention.

[Fig. 1B] Fig. 1B is a plan view of the fixed scroll of Fig.

1A viewed from a wall side.

10a

[Fig. 2] Fig. 2 is a perspective view illustrating the

orbiting scroll of Fig. 1.

[Fig. 3] Fig. 3 is a plan view illustrating end plate flat

sections provided in the fixed scroll.

[Fig. 4] Fig. 4 is a plan view illustrating a wall flat

section provided in the fixed scroll.

[Fig. 5] Fig. 5 is a schematic diagram illustrating a wall represented so as to extend in the spiral direction.

[Fig. 61 Fig. 6 is a partially enlarged view illustrating an

enlarged region of reference symbol Z in Fig. 1B.

[Fig. 7A] Fig. 7A is a side view illustrating a tip seal

clearance of a portion illustrated in Fig. 6, and illustrating

a state in which the tip seal clearance is relatively small.

[Fig. 7B] Fig. 7B is a side view illustrating the tip seal

clearance of the portion illustrated in Fig. 6, and

illustrating a state in which the tip seal clearance is

relatively large.

[Fig. 81 Fig. 8 is a graph illustrating an efficiency change

rate to a tip clearance change amount, according to a second

embodiment of the present invention.

[Fig. 9A] Fig. 9A is a partially enlarged sectional view

illustrating a portion between a tooth tip and a tooth bottom,

and illustrating a state in which an oil film seal is formed.

[Fig. 9B] Fig. 9B is a partially enlarged sectional view

illustrating a portion between the tooth tip and the tooth

bottom, and illustrating a state in which the oil film seal is

destroyed.

[Fig. 10] Fig. 10 is a plan view illustrating a fixed scroll

and an orbiting scroll according to a third embodiment of the

present invention, viewed from a wall side of a fixed scroll.

[Fig. 11A] Fig. 11A is a longitudinal sectional view

illustrating a modified example, and illustrating combination of scrolls having no step section.

[Fig. 11B] Fig. 11B is a longitudinal sectional view

illustrating a modified example, and illustrating combination

of stepped scrolls.

[Description of Embodiments]

[0018]

[First Embodiment]

Hereinafter, a first embodiment according to the present

invention will be described with reference to the drawings.

Fig. 1 illustrates a fixed scroll (first scroll member) 3

and an orbiting scroll (second scroll member) 5 of a scroll

compressor (scroll fluid machine) 1. The scroll compressor 1

is used as a compressor that compresses a gas refrigerant

(fluid) for performing refrigerating cycle of an air

conditioner or the like, for example.

[0019]

The fixed scroll 3 and the orbiting scroll 5 are a

compression mechanism made of metal such as aluminum alloy and

iron, and are housed in a housing (not illustrated). The

fixed scroll 3 and the orbiting scroll 5 suck, from the outer

circumferential side, fluid guided into the housing, and

discharge the compressed fluid from a discharge port 3c at the

center of the fixed scroll 3 to the outside.

[0020]

The fixed scroll 3 is fixed to the housing, and includes

a substantially disk-shaped end plate (first end plate) 3a,

and a spiral wall (first wall) 3b erected on a side surface of

the end plate 3a, as illustrated in Fig. 1A. The orbiting

scroll 5 includes a substantially disk-shaped end plate

(second end plate) 5a, and a spiral wall (second wall) 5b

erected on a side surface of the end plate 5a. The respective

spiral shapes of the walls 3b, 5b are each defined by using,

for example, an involute curve or an Archimedes curve.

[0021]

The center of the fixed scroll 3 and the center of the

orbiting scroll 5 are separated by an orbiting radius p, are

engaged such that the phases of the walls 3b, 5b are shifted

by 1800, and are assembled so as to have slight clearances

(tip clearances) in the height direction between tooth tips

and tooth bottoms of the walls 3b, 5b of both the scrolls at

normal temperature. Consequently, a plurality of pairs of

compression chambers formed so as to be surrounded by the end

plates 3a, 5a and the walls 3b, 5b are formed between the

scrolls 3, 5 so as to be symmetrical with respect to the

scroll centers. The orbiting scroll 5 revolves around the

fixed scroll 3 by a rotation prevention mechanism such as an

Oldham ring (not illustrated).

[0022]

As illustrated in Fig. 1A, inclined sections that continuously reduce an inter-facing-surface distance L between the facing end plates 3a, 5a from the outer circumferential sides toward the inner circumferential sides of the spiral walls 3b, 5b are provided.

[0023]

As illustrated in Fig. 2, a wall inclined section 5bl

having a height that continuously reduces from the outer

circumferential side toward inner circumferential side is

provided in the wall 5b of the orbiting scroll 5. An end

plate inclined section 3al (see Fig. 1A) that inclines in

accordance with inclination of the wall inclined section 5bl

is provided in a tooth bottom surface of the fixed scroll 3

facing a tooth tip of this wall inclined section 5bl. The

continuous inclined section is formed by these wall inclined

section 5bl and end plate inclined section 3al. Similarly, a

wall inclined section 3bl having a height that continuously

inclines from the outer circumferential side toward inner

circumferential side is provided in the wall 3b of the fixed

scroll 3, and an end plate inclined section 5al facing a tooth

tip of this wall inclined section 3bl is provided in the end

plate 5a of the orbiting scroll 5.

[0024]

The meaning of "continuously" in the inclined section

mentioned in this embodiment is not limited to smoothly

connected inclination, but includes inclination that is formed by stepwisely connecting small steps inevitably generated in machining, and that is an inclined section continuously inclined as a whole. However, the above meaning does not include a large step such as a so-called stepped scroll.

[0025]

The wall inclined sections 3bl, 5bl and/or the end plate

inclined sections 3al, 5al are coated. Examples of the

coating include manganese phosphate treatment, and nickel

phosphorus plating.

[0026]

As illustrated in Fig. 2, wall flat sections 5b2, 5b3

each having a constant height are provided on the innermost

circumferential side and the outermost circumferential side of

the wall 5b of the orbiting scroll 5, respectively. These

wall flat sections 5b2, 5b3 are each provided over a region of

1800 around the center 02 (see Fig. 1A) of the orbiting scroll

5. Wall inclined connecting sections 5b4, 5b5 serving as bent

sections are provided at respective positions where the wall

flat sections 5b2, 5b3 and the wall inclined section 5bl are

connected.

Similarly, end plate flat sections 5a2, 5a3 each having a

constant height are provided on a tooth bottom of the end

plate 5a of the orbiting scroll 5. These end plate flat

sections 5a2, 5a3 are also each provided over a region of 1800

around the center of the orbiting scroll 5. End plate inclined connecting sections 5a4, 5a5 serving as bent sections are provided at respective positions where the end plate flat sections 5a2, 5a3 and the end plate inclined section 5al are connected.

[0027]

As illustrated by hatching in Fig. 3 and Fig. 4, end

plate flat sections 3a2, 3a3, wall flat sections 3b2, 3b3, end

plate inclined connecting sections 3a4, 3a5, and wall inclined

connecting sections 3b4, 3b5 are provided in the fixed scroll

3, like the orbiting scroll 5.

[0028]

Fig. 5 illustrates the walls 3b, 5b represented so as to

extend in the spiral direction. As illustrated in Fig. 5, the

wall flat sections 3b2, 5b2 on the innermost circumferential

sides are each provided so as to extend over a distance D2,

and the wall flat sections 3b3, 5b3 on the outermost

circumferential sides are each provided so as to extend over a

distance D3. The distance D2 and the distance D3 are

equivalent to the lengths of the regions of 1800 (1800 or more

and 3600 or less, preferably 2100 or less) around the centers

01, 02 of the scrolls 3, 5. The wall inclined sections 3bl,

5bl are provided between the wall flat sections 3b2, 5b2 on

the innermost circumferential sides and the wall flat sections

3b3, 5b3 on the outermost circumferential sides so as to

extend over a distance Dl. Where each of height differences between the wall flat sections 3b2, 5b2 on the innermost circumferential sides and the wall flat sections 3b3, 5b3 on the outermost circumferential sides is denoted by h, the inclination T of each of the wall inclined sections 3bl, 5bl is expressed by the following expression.

0 = tan-' (h/D1) ... (1)

Thus, the inclination T in the inclined section is

constant with respect to the circumferential direction in

which each of the spiral walls 3b, 5b extends. The distance

Dl is longer than the distance D2, and is longer than the

distance D3.

For example, in this embodiment, the specifications of

the scrolls 3, 5 are as follows.

(1) Orbiting radius p [mm]: 2 or more and 15 or less,

preferably 3 or more and 10 or less

(2) The number of turns of each of the walls 3b, 5b: 1.5 or

more and 4.5 or less, preferably 2.0 or more and 3.5 or less

(3) Height difference h [mm]: 2 or more and 20 or less,

preferably 5 or more and 15 or less

(4) h/Lout (wall height on outermost circumferential side):

0.05 or more and 0.35 or less, preferably 0.1 or more and 0.25

or less

(5) Angular range of inclined section (angular range

equivalent to distance Dl) [°]: 180 or more and 1080 or less,

preferably 360 or more and 720 or less

(6) Angle 0 [°] of inclined section: 0.2 or more and 4 or

less, preferably 0.5 or more and 2.5 or less

[0029]

In Fig. 6, an enlarged view of a region indicated by

reference symbol Z in Fig. 1B is illustrated. As illustrated

in Fig. 6, a tip seal 7 is provided on the tooth tip of the

wall 3b of the fixed scroll 3. The tip seal 7 is made of

resin, and comes into contact with the tooth bottom of the end

plate 5a of the facing orbiting scroll 5 to seal fluid. The

tip seal 7 is housed in a tip seal groove 3d formed in the

circumferential direction of the tooth tip of the wall 3b.

Compressed fluid enters this tip seal groove 3d, and the tip

seal 7 is pressed from a back surface, and pressed out to the

tooth bottom side to be brought into contact with the facing

tooth bottom. Similarly, a tip seal is provided on the tooth

tip of the wall 5b of the orbiting scroll 5.

[0030]

When both the scrolls 3, 5 relatively revolve, the

respective positions of the tooth tip and the tooth bottom

relatively shift by an orbiting diameter (orbiting radius p x

2). In the inclined section, a tip clearance between the

tooth tip and the tooth bottom changes due to this position

shift between the tooth tip and the tooth bottom. A tip

clearance change amount Ah [mm] is, for example, 0.05 or more

and 1.0 or less, preferably 0.1 or more and 0.6 or less. For example, the tip clearance T is small in Fig. 7A, and the tip clearance T is large in Fig. 7B. Even when this tip clearance

T changes due to the orbiting movement, the tip seal 7 is

pressed to the tooth bottom side of the end plate 5a from the

back surface by compressed fluid, and therefore can seal

following this pressing.

[0031]

As illustrated in Fig. 7, a tip clearance change amount

AT in which the tip clearance T changes during a single orbit

can be expressed by the following expression.

AT = 2p x tan T ... (2)

Herein, p denotes an orbiting radius.

[0032]

The tip clearance change amount AT is 50% or less of the

height dimension Hc of the tip seal in the height direction of

each of the walls 3b, 5b.

[0033]

The aforementioned scroll compressor 1 is operated as

follows.

The orbiting scroll 5 revolves around the fixed scroll 3

by a driving source such as an electric motor (not

illustrated). Consequently, fluid is sucked from the outer

circumferential sides of the scrolls 3, 5, and is taken in the

compression chambers surrounded by the walls 3b, 5b and the

end plates 3a, 5a. The fluid in the compression chambers is sequentially compressed in accordance with movement from the outer circumferential side to the inner circumferential side, and the compressed fluid is finally discharged from the discharge port 3c formed in the fixed scroll 3. When the fluid is compressed, the fluid is compressed also in the height direction of the walls 3b, 5b in the inclined sections formed by the end plate inclined sections 3al, 5al and the wall inclined sections 3bl, 5bl, and is three-dimensionally compressed.

[0034]

According to this embodiment, the following working

effects are exhibited.

To cope with the above, the tip clearance change amount

AT is made to be 50% or less of the height dimension Hc of the

tip seal 7. Consequently, even when the tip seal 7 advances

and retreats in the height direction from the tip seal groove

3d by an amount in accordance with the tip clearance change

amount AT, it is possible to avoid detachment of the tip seal

7 from the tip seal groove 3d, and prevent drop of the tip

seal 7.

The tip clearance change amount AT may be 20% or less of

the height dimension Hc of the tip seal 7.

[0035]

[Second Embodiment]

Now, a second embodiment of the present invention will be described.

This embodiment is different in a way of thinking about

setting an upper limit of a tip clearance change amount AT,

and other configurations are similar. Therefore, in the

following description, only differences from the first

embodiment will be described. Other configurations are

similar, and therefore description thereof will be omitted.

[00361

In this embodiment, AT/Lout which is a value obtained by

dividing a tip clearance change amount AT by the height of an

outermost circumference of each of walls 3b, 5b (see reference

symbol Lout of Fig. 2) is 0.01 or less. The reason will be

described with reference to Fig. 8 and Fig. 9.

In Fig. 8, a horizontal axis indicates AT/Lout, and a

vertical axis indicates an efficiency change rate. The

efficiency change rate indicates a rate of efficiency at

predetermined AT/Lout in a case where the tip clearance change

amount AT is zero, that is, in a case where efficiency in a

case of no inclination in a wall height, a so-called two

dimensional scroll is 1. As illustrated in Fig. 8, when

AT/Lout is 0.01, reduction of the efficiency change rate is

less than 1%. Therefore, when AT/Lout is 0.01 or less, the

reduction of the efficiency change rate can be limited to be

less than 1%.

[0037]

As illustrated in Fig. 9A, it is considered that in a

range where AT/Lout is 0.01 or less, each tip clearance T is

made to be a predetermined value or less, so that oil film

seals OS by lubricating oil are formed between tooth tips of

the walls 3b, 5b and tooth bottoms of facing end plates 5a,

3a. Thus, since the oil film seal OS in each tip clearance T

is secured, fluid leakage in compression chambers is reduced,

and reduction of the efficiency change rate becomes small.

On the other hand, when AT/Lout becomes larger than 0.01,

the tip clearance T increased, and as illustrated in Fig. 9B,

an oil film in each tip clearance T is separated, and the oil

film seal OS (see Fig. 9A) disappears, and fluid leakage in

the compression chambers occurs. Consequently, the efficiency

change rate is significantly reduced.

[0038]

As described above, according to this embodiment, AT/Lout

is made to be 0.01 or less, so that the oil film seal OS in

each tip clearance T is maintained. Consequently, it is

possible to maintain expected efficiency.

[0039]

[Third Embodiment]

Now, a third embodiment of the present invention will be

described.

In this embodiment, setting of a lower limit of a tip

clearance T will be described. Other configurations are similar to those of each of the aforementioned embodiments.

Therefore, in the following description, only differences from

each of the aforementioned embodiments will be described.

Other configurations are similar, and therefore description

thereof will be omitted. This embodiment can be used by

combination with the first embodiment or the second

embodiment.

[0040]

In this embodiment, as to setting of tip clearances T

between tooth tips of walls 3b, 5b and tooth bottoms of end

plates 5a, 3a, a torsion angle 50 around the center of each of

scrolls 3, 5 due to an assembly error is considered. As

illustrated in Fig. 10, when the scrolls 3, 5 are assembled to

be operated, an assembly error inevitably occurs due to

dimensional accuracy of an Oldham ring, or location accuracy

of a centering pin or the like, and the torsion angle 50 is

generated due to backlash generated around the centers of the

scrolls 3, 5. Fig. 10 is a diagram similar to Fig. 1B. Gas

pressure inside compression chambers is added during

operation, and therefore the tooth tips of the inclined

sections of the walls 3b, 5b, and the tooth bottoms of the end

plates 5a, 3a approach each other due to the backlash around

the centers of the scrolls 3, 5, so that the tip clearances T

reduce. Each of these tip clearance reduction amounts 5T is

expressed by the following expression.

5T = r x 50 x tan P ... (3)

Herein, r denotes a radius on an outer circumferential

side where an inclined section starts, that is, a radius at

each of wall inclined connecting sections 3b5, 5b5 (see Figs.

2 and 5) on the outer circumferential sides of the walls 3b,

5b. T denotes an inclination of the inclined section (see

Fig. 5). The torsion angle 50 can be obtained by measurement

of an actual object. The dimensions of portions that cause

torsion of the scrolls such as the dimensional accuracy of the

Oldham ring and the location accuracy of the centering pin are

individually measured, and the torsion angle 50 can be also

obtained by calculation from these dimension.

[0041]

In this embodiment, when the scrolls 3, 5 are assembled,

each tip clearance T is made larger than the tip clearance

reduction amount 5T obtained from the aforementioned

expression (3) obtained by considering the radius on the outer

circumferential side where the inclined section starts, the

tip clearance reduction amount, and the inclination T of the

inclined section. Consequently, it is possible to avoid

interference between the tooth tips and the tooth bottoms.

[0042]

The end plate inclined sections 3al, 5al and the wall

inclined sections 3bl, 5bl are provided in both the scrolls 3,

5 in each of the aforementioned embodiments, but may be provided in either one.

Specifically, as illustrated in Fig. 11A, in a case where

a wall inclined section 5bl is provided in a first wall (for

example, an orbiting scroll 5), and an end plate inclined

section 3al is provided in a second end plate 3a, a second

wall and a first end plate 5a may be flat.

As illustrated in Fig. 11B, a shape formed by combination

with a conventional stepped shape, that is, a shape, in which

while an end plate inclined section 3al is provided in an end

plate 3a of a fixed scroll 3, a step section is provided in an

end plate 5a of an orbiting scroll 5, may be combined.

[0043]

In each of the aforementioned embodiment, the wall flat

sections 3b2, 3b3, 5b2, 5b3 and the end plate flat sections

3a2, 3a3, 5a2, 5a3 are provided. However, the flat sections

on the inner circumferential sides and/or the outer

circumferential sides may be omitted, and the inclined

sections may be provided so as to extend over the entire walls

3b, 5b.

[0044]

The present invention is applied to a scroll compressor

in each of the aforementioned embodiments, but can be also

applied to a scroll expander used as an expander.

[Reference Signs List]

[0045]

1 scroll compressor (scroll fluid machine)

3 fixed scroll (first scroll member)

3a end plate (first end plate)

3al end plate inclined section

3a2 end plate flat section (inner circumferential side)

3a3 end plate flat section (outer circumferential side)

3a4 end plate inclined connecting section (inner

circumferential side)

3a5 end plate inclined connecting section (outer

circumferential side)

3b wall (first wall)

3bl wall inclined section

3b2 wall flat section (inner circumferential side)

3b3 wall flat section (outer circumferential side)

3b4 wall inclined connecting section (inner circumferential

side)

3b5 wall inclined connecting section (outer circumferential

side)

3c discharge port

3d tip seal groove

orbiting scroll (second scroll member)

5a end plate (second end plate)

5al end plate inclined section

5a2 end plate flat section (inner circumferential side)

5a3 end plate flat section (outer circumferential side)

5a4 end plate inclined connecting section (inner

circumferential side)

5a5 end plate inclined connecting section (outer

circumferential side)

5b wall (second wall)

5bl wall inclined section

5b2 wall flat section (inner circumferential side)

5b3 wall flat section (outer circumferential side)

5b4 wall inclined connecting section (inner circumferential

side)

5b5 wall inclined connecting section (outer circumferential

side)

7 tip seal

Hc height dimension of tip seal

L inter-facing-surface distance

OS oil film seal

T tip clearance

AT tip clearance change amount

5T tip clearance reduction amount

p inclination

torsion angle

Claims

[THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:]

1. A scroll fluid machine comprising:

a first scroll member provided with a spiral first wall

on a first end plate; and

a second scroll member that is provided with a spiral

second wall on a second end plate disposed so as to face the

first end plate, and that relatively revolves by engagement

between the second wall and the first wall, wherein

an inclined section that continuously reduces an inter

facing-surface distance between the first end plate and the

second end plate facing each other, from an outer

circumferential side toward an inner circumferential side of

each of the first wall and the second wall is provided,

each of the inclined sections is provided over a range of

1800 or more around a spiral center,

a groove section formed in a tooth tip of each of the

first wall and the second wall corresponding to the inclined

sections is provided with a tip seal that comes into contact

with a facing tooth bottom to seal fluid the tip seal being

pressed from a back surface by compressed fluid entering the

groove section while following a change of a tip clearance

change amount AT due to orbiting movement,

where an orbiting radius of the scroll member that orbits

is denoted by p, and an inclination in a spiral direction of

the inclined section is denoted by T, the tip clearance change amount AT is defined by an expression as follows:

AT = 2p x tan T, and

the tip clearance change amount AT is 50% or less of a

height dimension of the tip seal in a height direction of the

wall.

2. A scroll fluid machine comprising:

a first scroll member provided with a spiral first wall

on a first end plate; and

a second scroll member that is provided with a spiral

second wall on a second end plate disposed so as to face the

first end plate, and that relatively revolves by engagement

between the second wall and the first wall, wherein

an inclined section that continuously reduces an inter

facing-surface distance between the first end plate and the

second end plate facing each other, from an outer

circumferential side toward an inner circumferential side of

each of the first wall and the second wall is provided,

each of the inclined sections is provided over a range of

1800 or more around a spiral center,

where an orbiting radius of the scroll member that orbits

is denoted by p, and an inclination in a spiral direction of

the inclined section is denoted by T, a tip clearance change

amount AT is defined by an expression as follows:

AT = 2p x tan T, and

a value obtained by dividing the tip clearance change amount AT by a height of an outermost circumference of the wall is 0.01 or less.

3. A scroll fluid machine comprising:

a first scroll member provided with a spiral first wall

on a first end plate; and

a second scroll member that is provided with a spiral

second wall on a second end plate disposed so as to face the

first end plate, and that relatively revolves by engagement

between the second wall and the first wall, wherein

an inclined section that continuously reduces an inter

facing-surface distance between the first end plate and the

second end plate facing each other, from an outer

circumferential side toward an inner circumferential side of

each of the first wall and the second wall is provided,

each of the inclined sections is provided over a range of

1800 or more around a spiral center, and

a tip clearance between a tooth tip of the wall and a

tooth bottom of the end plate is set larger than a tip

clearance reduction amount based on a torsion angle around a

center of the scroll member due to an assembly error.