JP2000110749A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll compressor capable of setting a pseudo variable compression ratio to the low compression ratio during low revolution so as to reduce excessive compression, and to a high compression ratio during high revolution by increasing the revolution speed to the set value. SOLUTION: A scroll compressor is provided with a fixed scroll having a spiral lap formed of involute curve stood on an end plate, a rotary scroll having a spiral lap formed of involute curve stood on the end plate engaged with the fixed scroll face to face, and a compression chamber defined by the inner peripheral surface of the rotary scroll lap 6b and the outer peripheral surface of the fixed scroll lap 4b. The scroll compressor compresses gas by causing both scrolls to perform relative motions such that the capacity is reduced as it moves toward the center of the scroll. Involutes 4f, 6g offset with each other are formed in one of involutes engaged with either the fixed scroll lap 4b or rotary scroll lap 6b along inner radial direction, forming very small gap between those laps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor, and more particularly, to a structure of a wrap of a fixed scroll and an orbiting scroll capable of preventing overcompression.

[0002]

2. Description of the Related Art A scroll compressor has two compression chambers as shown in FIGS.
b 'inner wall 6d' and fixed scroll wrap 4b 'outer wall 4
c ', a second compression chamber 5b' formed by the outer wall surface 6e 'of the orbiting scroll wrap 6b' and the inner wall surface 4d 'of the fixed scroll wrap 4b'.
And two compression chambers 5a 'and 5
The gas in the compression chamber is compressed by performing a relative movement between the two scrolls so that the volume decreases as b ′ moves toward the center of the scroll, and is discharged from the discharge holes 11.

The spiral curves forming the first and second compression chambers 5a 'and 5b' generally use an involute curve, and the ratio of the volume of the compression chamber at the start of compression to the volume of the compression chamber at the start of discharge determined by the involute curve. Is the specific compression ratio. That is, the specific compression ratio is determined by the winding angle at the beginning and end of winding of the involute curve. When a scroll compressor is used as a refrigerant compressor for air conditioning, the suction pressure and discharge pressure of the refrigerant change due to variable speed operation and fluctuations in air conditioning load. Then, due to the difference between the actual compression ratio and the specific compression ratio (set compression ratio), when the compressor is running at a low speed, the power loss due to overcompression increases, and the compression efficiency decreases.

After the second compression chamber 5b 'reaches the set compression ratio, it communicates with the discharge hole 11 (arrow A in FIG. 7), so that a sufficient discharge passage can be secured. On the other hand, the first compression chamber
5a 'passes through between the inner wall surface 6d' of the orbiting scroll wrap 6b 'and the outer wall surface 4c' of the fixed scroll wrap 4b '(arrow B in FIG. 7) before communicating with the discharge hole 11. The gap between the scroll wrap wall surfaces immediately after the start of the discharge is narrow, and becomes a resistance when the discharge gas passes, which increases the gas pressure and causes overcompression.

As a measure for reducing such over-compression, there is a method described in Japanese Patent Publication No. 5-41839 shown in FIGS. 8 and 9. Orbiting scroll head plate 6
a ′ is provided with a concave groove portion (counterbore) 6A having a sectional shape substantially the same as that of the discharge hole 11. The gas in the first compression chamber 5a '
It flows to the discharge hole 11 via the concave groove 6A (arrow C in FIG. 8).
Therefore, a sufficient discharge passage can be secured, and excessive compression can be reduced.

However, in this method, the gas is discharged after passing through the groove 6A (arrow D in FIG. 9).
There is a problem that a loss due to the turbulence may occur instead of a smooth gas flow, and the number of processing steps increases due to the provision of the concave groove 6A.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and comprises an involute offset at the beginning of winding of an inner involute of a scroll wrap. It is another object of the present invention to provide a scroll compressor capable of achieving a pseudo variable compression ratio that increases to a set number of revolutions at the time of high rotation.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a fixed scroll in which a spiral wrap having an involute curve is erected on a head plate having a discharge hole in the center, An orbiting scroll in which a spiral wrap having an involute curve is erected on a head plate meshing opposite to the fixed scroll, and a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap. A scroll compressor configured to compress the gas by performing a relative motion between the two scrolls so as to reduce the volume as the scroll moves toward the center of the scroll, and discharge the compressed gas from the discharge hole to a discharge chamber. In the involute throat, the fixed scroll wrap and the orbiting scroll wrap mesh with each other. Et or one, constitutes an involute which is predetermined width offset along the radially inwardly and has a configuration of forming the minute gap between the wraps meshing with each other.

A fixed scroll in which a spiral wrap made of an involute curve is erected on a head plate having a discharge hole in the center, and a spiral wrap made of an involute curve are mounted on a head plate which meshes with the fixed scroll facing the fixed scroll. An orbiting scroll provided upright; a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap; In a scroll compressor that compresses gas by performing relative motion and discharges the compressed gas from the discharge hole to the discharge chamber, the fixed scroll wrap and the orbiting scroll wrap may have one of the involutes that mesh with each other. A predetermined width offset along the radial outside Configure volute has a structure obtained by forming the minute gap between the wraps meshing with each other.

In addition, a fixed scroll in which a spiral wrap made of an involute curve is erected on a head plate having a discharge hole in the center, and a spiral wrap made of an involute curve are mounted on a head plate which meshes with the fixed scroll. An orbiting scroll provided upright; a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap; In a scroll compressor that compresses gas by performing relative motion and discharges the compressed gas from the discharge hole to the discharge chamber, the fixed scroll wrap and the orbiting scroll wrap may have one of the involutes that mesh with each other. A predetermined width offset along the radially inner and outer It has been constructed involute, and has a configuration of forming the minute gap between the wraps meshing with each other.

[0011] Further, the offset involute is formed at a winding start portion of the wrap.

Further, the orbiting scroll and the fixed scroll have an asymmetric configuration.

[0013] The involute curve may be changed to an Archimedes curve.

[0014]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a transverse sectional view of a scroll compressor showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a scroll wrap, and FIG. 3 is an enlarged sectional view of a main part showing a first embodiment of the present invention. In the drawing, a compression unit 2 and an electric motor 3 are arranged in a sealed container 1, and the compression unit 2 is swirled to form a plurality of compression chambers 5 by meshing with the fixed scroll 4 and the fixed scroll 4. A scroll 6, an Oldham ring 7 for preventing the orbiting scroll 6 from rotating, and a crankshaft 8 attached to one end of the orbiting scroll 6
, And a bearing 10 that supports the crankshaft 8 constitutes a scroll compressor.

In this configuration, a spiral fixed scroll wrap 4b composed of an involute curve standing upright on the fixed head plate 4a is integrally formed, and the fixed scroll 4 fixed to the bearing 10 and the involute curve standing upright on the orbiting head plate 6a are formed. A plurality of compression chambers 5 are formed by meshing a spiral scroll wrap 6b having a spiral shape and a rotary scroll 6 integrally formed with a rotary drive shaft 6c on the back surface.

Reference numeral 11 denotes a discharge hole. The discharge hole 11 is located near the center of the fixed scroll 4, and although not shown, the suction hole is provided so as to intersect with the end of winding of the outer periphery of the wrap 4b of the fixed scroll 4. .

The compression chamber 5 is provided with the orbiting scroll wrap.
6b inner wall surface 6d and the fixed scroll wrap 4b outer wall surface 4c
And a second compression chamber 5b formed by an outer wall surface 6e of the orbiting scroll wrap 6 and an inner wall surface 4d of the fixed scroll wrap 4b. The gas in the compression chamber is compressed by performing relative movement of the two scrolls so that the volume is reduced as the two compression chambers 5a and 5b move toward the center of the scroll, and the compressed gas is discharged from the discharge hole 11. The liquid is discharged into the chamber 13 and discharged from the discharge pipe 14 to the outside of the sealed container 1.

FIG. 3 shows a first embodiment of the present invention. One of the fixed scroll wrap 4b and the orbiting scroll wrap 6b meshes with one of the involutes 4e, 6f which are engaged with each other along a radially inner side. An involute 4f or 6g offset by a dotted line of width is formed, and a minute gap 4g or 6h is formed between the offset involute 4f or 6g and the involute 4e or 6f indicated by a solid line.

In the above configuration, when the compressor is operated at a low rotation speed, the gas in the first compression chamber 5a and the second compression chamber 5b leaks from the gap 4g and / or 6h in the direction of the discharge hole 11. The compression ratio becomes low, and a reduction in power loss due to overcompression can be prevented. Further, when the compressor is operated at a high rotation speed, the small gap 4g or 6h
The relative leakage amount of gas per unit time from the gas becomes small, the sealing performance of the small gap 4g is improved, and a high compression ratio is obtained. As described above, by forming an involute offset to the inner involute of the scroll wrap and forming a small gap, a pseudo compression to reduce the over-compression to a low compression ratio at low rotation and increase to a set rotation speed at high rotation. A scroll compressor that can have a variable compression ratio and can improve compression efficiency.

FIG. 4 shows a second embodiment of the present invention. One of the fixed scroll wrap 4b and the orbiting scroll wrap 6b meshes with one of the involutes 4e 'and 6f' which engage with each other. To form an involute 4f 'or 6g' offset by a dotted line of a predetermined width, and this offset involute 4f 'or 6g'
A small gap 4g 'or 6h' is formed between g 'and the involute 4e' or 6f 'indicated by a solid line. In the above configuration, the same effect as in the first embodiment can be obtained, a low compression ratio can be set at a low rotation speed to reduce overcompression, and a high rotation speed can be set to a pseudo variable compression ratio that increases to a set rotation speed. The scroll compressor can improve the compression efficiency.

FIGS. 5A and 5B show a third embodiment of the present invention. As shown in FIG. 5A, the inner and outer involutes 4 of the fixed scroll wrap 4b are formed.
e, 4e ′, offset involutes 4f ′, 6g ′ indicated by dotted lines in the radial direction, and a minute gap between the offset involutes 4f, 4f ′ and the involutes 4e, 4e ′ indicated by solid lines. 4g and 4g 'are formed.

As shown in FIG. 5B, the inner and outer involutes 6 of the orbiting scroll wrap 6b are formed.
f, 6f ', constitute an offset involute 6g, 6g' indicated by a dotted line in the radial direction, and a minute gap 6h between the offset involute 6g, 6g 'and the involute 6f, 6f' indicated by a solid line. , 6h '. In the above configuration, the same effect as in the first embodiment can be obtained, a low compression ratio can be set at a low rotation speed to reduce overcompression, and a high rotation speed can be set to a pseudo variable compression ratio that increases to a set rotation speed. The scroll compressor can improve the compression efficiency.

In the above embodiment, the offset involute is formed at the start of winding of the wrap. Further, the shape of the orbiting scroll and the fixed scroll is not limited to the symmetrical shape, and may be applied to an asymmetrical scroll. Furthermore, in addition to the involute curve, an Archimedes curve or the like may be used. If the start position of those curves is delayed, the same effect as described above can be obtained.

[0024]

As described above, according to the present invention, an involute offset at the beginning of the inner involute winding of the scroll wrap is formed to form a small gap, so that a low compression ratio is obtained at a low rotation speed to reduce overcompression. ,
At the time of high rotation, the pseudo variable compression ratio can be increased to the set rotation speed, and the scroll compressor can improve the compression efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a scroll compressor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a scroll wrap, showing an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a main part showing the first embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a main part showing a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a main part showing a third embodiment of the present invention;
(A) shows an involute offset on both sides of the fixed scroll, and (B) shows an involute offset on both sides of the orbiting scroll.

FIG. 6 is an enlarged sectional view of a main part of a scroll wrap according to a conventional example.

FIG. 7 is an enlarged sectional view of a main part of a wrap center according to a conventional example.

FIG. 8 is an enlarged sectional view of a main part of a wrap center according to another conventional example.

FIG. 9 is an enlarged sectional view of the center of a wrap according to another conventional example.

[Description of Signs] 1 Sealed container 2 Compressor 3 Electric motor 4 Fixed scroll 4a Fixed end plate 4b Fixed scroll wrap 4c Fixed scroll wrap outer wall 4d Fixed scroll wrap inner wall 4e, 6f Notch 4f, 6g Offset involute 4g, 6h Micro gap 5a first compression chamber 5b second compression chamber 6 orbiting scroll 6a orbiting head plate 6b orbiting scroll wrap 6c orbiting drive shaft 6d orbiting scroll wrap inner wall surface 6e orbiting scroll wrap outer wall surface 11 discharge hole 13 discharge chamber

Claims (6)

[Claims] 1. A fixed scroll in which a spiral wrap made of an involute curve is erected on a head plate having a discharge hole in the center, and a spiral wrap made of an involute curve is mounted on a head plate meshing opposite to the fixed scroll. An orbiting scroll provided upright; a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap; In a scroll compressor which compresses gas by performing relative motion and discharges the compressed gas from the discharge hole to the discharge chamber, the scroll scroll wrap and the orbiting scroll wrap may be in one of the meshed involutes. , A given width offset along the radial inside Configure chute, scroll compressor, characterized in that by forming a small gap between the wraps meshing with each other. 2. A fixed scroll in which a spiral wrap made of an involute curve is erected on a head plate having a discharge hole in the center, and a spiral wrap made of an involute curve is mounted on a head plate meshing with and facing the fixed scroll. An orbiting scroll provided upright; a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap; In a scroll compressor which compresses gas by performing relative motion and discharges the compressed gas from the discharge hole to the discharge chamber, the scroll scroll wrap and the orbiting scroll wrap may be in one of the meshed involutes. , The inboard offset a predetermined width along the radial outside Configure chute, scroll compressor, characterized in that by forming a small gap between the wraps meshing with each other. 3. A fixed scroll in which a spiral wrap made of an involute curve is erected on a head plate having a discharge hole in the center, and a spiral wrap made of an involute curve is mounted on a head plate meshing opposite to the fixed scroll. An orbiting scroll provided upright; a compression chamber formed by an inner wall surface of the orbiting scroll wrap and an outer wall surface of the fixed scroll wrap; In a scroll compressor which compresses gas by performing relative motion and discharges the compressed gas from the discharge hole to the discharge chamber, the scroll scroll wrap and the orbiting scroll wrap may be in one of the meshed involutes. Offset, predetermined width along radial inside and outside Involute constitute a scroll compressor, characterized in that by forming a small gap between the wraps meshing with each other. 4. The scroll compressor according to claim 1, wherein the offset involute is formed at a winding start portion of a wrap. 5. The scroll compressor according to claim 1, wherein the orbiting scroll and the fixed scroll have asymmetric shapes. 6. The scroll compressor according to claim 1, wherein the involute curve is changed to an Archimedes curve.