JPH04203282A - Scroll fluid machine - Google Patents

Abstract

PURPOSE:To make a uniform gap between each of laps and each of end plates by a method wherein each of the laps of a circulating scroll and a fixed scroll is formed from both side laps having different thermal expansion coefficient into an axial two-layered structure and a rate of one side lap is increased from a central side to an outer circumferential side. CONSTITUTION:A circulating scroll 21 is comprised of an end plate 22, a swirled lap part 25 vertically arranged at a tooth bottom part 22A of the end plate 22 and a hub part 24. In this case, the lap part 23 is formed such that a base end part 23A acting as an one side lap part integrally formed with the end plate 22 of cast iron having a low thermal expansion coefficient and an extremity end part 23B acting as the other side lap part formed from aluminum alloy having a high thermal expansion coefficient are applied to form a two-layer structure in respect to a height direction of the lap part 23. Then, the lap part 23 is set such that a rate of the extremity end 23B occupying the lap part 23 is gradually increased. The fixed scroll 25 is also formed in the same manner as that of the circulating scroll 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll-type fluid machine suitable for use in, for example, an air compressor or a vacuum pump.

[Prior Art] An oil-free air compressor will be described as an example of a conventional scroll fluid machine with reference to FIGS. 3 and 4.

In the figure, 1 is a casing, and 2 is a casing body that constitutes the casing 1 together with a front casing 3 (described later). It is formed into a bottomed cylindrical shape including a bearing portion 2B extending inward and a cylindrical portion 2C extending from the outer circumferential side of the bottom portion 2A toward the front casing 3.

Reference numeral 3 denotes a stepped cylindrical front casing fixed to the tip of the cylindrical portion 2C of the casing body 2, and an annular portion 3A is integrally provided on the inner peripheral side of the front casing 3 to protrude radially inward. An orbiting scroll 6, which will be described later, is provided on the inner peripheral side of the annular portion 3A.
A thrust receiving portion 3B is formed to receive a load in the thrust direction by slidingly contacting the back surface of the thrust receiving portion 3B.

Reference numeral 4 denotes a drive shaft rotatably supported by bearings 5, 5 around the axis O-0 in the bearing portion 2B of the casing body 2, and the tip side of the drive shaft 4 extends into the casing 1 to form a crank. The axis 4A is the axis 0. of the crankshaft 4A.
-0. is eccentric by a predetermined dimension d with respect to the axis O-0 of the drive shaft 4. The base end side of the drive shaft 4 is connected to an electric motor (not shown) outside the casing 1, and is rotationally driven by the electric motor.

Reference numeral 6 indicates an orbiting scroll located between a thrust receiving part 3B of the front casing 3 and a thrust receiving part 15A of a fixed scroll 11, which will be described later, and rotatably mounted on the crankshaft 4A with a Zandwich clearance of a predetermined dimension δ. As shown in FIG. 4, the orbiting scroll 6 has a disk-shaped end plate 7, and is erected on the tooth bottom 7A side of the end plate 7, with the center side being the winding start end and the outer circumferential side being the winding end end. It is composed of a spiral wrap portion 8 and a boss portion 9 provided at the center of the back side of the end plate 7, and a crankshaft 4A is mounted within the boss portion 9 via a swing bearing 10.

For reasons described later, the height of the wrap portion 8 is assumed to be H1 at the beginning of winding, H2 at the middle, and H3 at the end of winding, H+ < H2 < H3... ( 1) It is formed by the following relationship.

Here, key grooves (not shown) are formed at predetermined intervals in the circumferential direction on the outer peripheral side of the back surface of the end plate 7, and an Oldham joint as a rotation prevention mechanism is provided between each key groove and the thrust receiving part 3B of the front casing 3. (not shown) is provided.

When the orbiting scroll 6 rotates the drive shaft 4, it is given a circular motion with a turning radius of dimension d by the crankshaft 4A, and is prevented from rotating by the Oldham joint, and the axis O- Rotate (revolution) around 0
It seems that they continue to do so.

1] shows a fixed scroll provided in abutment with the end face of the front casing 3 so as to cover the front end side of the casing 1, and the center of the fixed scroll 11 is aligned with the axis o - o of the drive shaft 4. An end plate 12 is arranged on the center side so as to coincide with the end plate 12, and a spiral-shaped end plate 12 is provided on the bottom 12A side of the end plate 12 with the relationship of the above formula (1) in the same way as the wrap part 8 of the orbiting scroll 6. Wrap portion] 3, and a cylindrical support portion 1 located on the outer peripheral side of the end plate 12 and formed with a U-shaped cross section.
4, and an annular plate 15 that abuts the front casing 3 is integrally formed on the distal end side of the support portion 14. Further, on the inner peripheral side of the annular plate 15, an annular thrust receiving part 15A that receives the load in the thrust direction from the orbiting scroll 6 is arranged on the thrust receiving part 3B of the front casing 3.
It is formed opposite to.

Here, the wrap portion] 3 of the fixed scroll 11 is arranged so as to overlap the wrap portion 8 of the orbiting scroll 6 at a predetermined angle C, and when the orbit scroll 6 rotates, the wrap portion] 3 overlaps the wrap portion 8 of the orbiting scroll 6. A plurality of compression chambers 16, 16 . It is designed to define...

Reference numerals 17 and 18 indicate a suction port and a discharge port formed in the fixed scroll 11, and the suction port 17 is connected to the outermost compression chamber 1.
A discharge port 18 is bored in the center of the end plate 2 so as to communicate with the compression chamber 6 located at the centermost side.

Reference numeral 19 indicates a counterweight located within the casing body 2 and fitted and fixed to the drive shaft 4, and the counterweight 19 is configured to balance the rotation of the drive shaft 4.

A scroll type air compressor according to the prior art has the above-described configuration, and when the drive shaft 4 is rotationally driven by an electric motor, this rotation is transmitted from the crank shaft 4A to the orbiting scroll 6 via the orbiting bearing 10. , the orbiting scroll 6 orbits around the axis O-0 of the drive shaft 4 with a radius of revolution of dimension d. Compression chambers 1.6, 16. and 1.6, 1.6, . ... is continuously reduced in size, and while the air sucked in from the suction port 17 is sequentially compressed in each compression chamber 16, this compressed air is discharged from the discharge port 18 to an external air tank (not shown), etc. Performs a compressive action.

Here, during compression, the orbiting scroll 6 is moved by the pressure in the high-pressure compression chamber 16 to cause the front casing 3 to slide.
・Since it is pressed by the receiving part 3B, a part of the compressed air discharged from the discharge I] 18 is introduced into the casing 1 through a back pressure introduction hole (not shown), and is introduced into the back side of the orbiting scroll 6. Back pressure is applied, thereby ensuring an appropriate thrust direction gap δ1 between each wrap portion 8.13 of the orbiting scroll 6 and the fixed scroll 11 and each end plate 7.12 as shown in the figure, and each compression chamber 16 This prevents pressure leaks and increases compression efficiency.

[Problem to be solved by the invention]

By the way, in the conventional technology described above, the pressure increases sequentially from the compression chamber 16 on the outer peripheral side to the compression chamber 16 on the center side. ) The temperature of the compression chamber 16 on the outer circumferential side (the winding end side) rises faster than that of the compression chamber 16 on the outer peripheral side (the winding end side). Not only does the thrust direction gap δ1 change between the outer peripheral side and the lap portion 8. ] 3 tooth tip surface is each mirror plate 7°12
There is a problem in that a galling phenomenon occurs due to contact with the bottoms 7A, 1.2A of the teeth, and the reliability, durability, compression efficiency, etc. of the compressor are significantly reduced.

In particular, in an oil-free compressor, each wrap portion 8, 1
3, the temperature gradient that occurs from the center side to the outer circumference side is significant, and the difference in the thrust direction gap δ between the center side and the outer circumference side becomes large.
The height dimensions H, , H2, and I(3 of each wrap portion 8, 13 are sequentially shortened in advance from the outer circumferential side to the center side according to the relationship of equation (1) above by the amount that is thermally expanded according to the temperature gradient,
The thrust direction gap δ is increased from the outer periphery to the center, so that during rated operation of the compressor,
The thrust direction gap δ1 of each wrap portion 8, 13 is configured to be substantially constant from the center side to the outer circumferential side. However, in this case, it takes time for each wrap portion 8, 13 to thermally expand from the winding start end to the winding end end to have the same height dimension. In particular, when the compressor is operated at a low pressure below the rated pressure, it takes a long time until the thrust direction gap δ becomes almost uniform due to thermal expansion of each wrap part 8.13, and during that time the compression efficiency only decreases. Furthermore, since the temperature rise in each wrap portion 8.13 changes depending on operating conditions such as air temperature, operating time, load condition, etc., there is a problem that the start-up performance and compression efficiency become unstable as the operating conditions change.

The present invention has been made in view of the problems of the prior art described above, and the present invention can equalize the thrust direction gap between each wrap portion and the end plate from the center side to the outer circumferential side of each wrap portion, and widen it. The object of the present invention is to provide a scroll type fluid machine in which the uniform thrust direction gap can be adjusted to be substantially constant over a temperature range.

[Means for Solving the Problems] A feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that each wrap portion of the orbiting scroll and the fixed scroll has one side wrap portion made of a material with a small coefficient of thermal expansion. and the other side wrap part made of a material with a large coefficient of thermal expansion to form a two-layer structure in the axial direction, and the proportion of the other side wrap part in each wrap part is varied from the center side to the outer periphery of each wrap part. This is because it is configured so that it increases towards the sides.

Further, either the casing or the fixed scroll includes a cylinder chamber, a liquid filled in the cylinder chamber, and a piston that is slidably provided in the cylinder chamber and receives the load in the thrust direction. It is preferable to provide a thrust receiving portion.

[Effect]

With the above configuration, a temperature gradient is generated in each lap part of the orbiting scroll and the fixed scroll from the center side to the outer circumferential side due to the compression heat of the compression chamber, and the m
Since the individual lug portion and the other side wrap portion thermally expand, each wrap portion as a whole expands thermally almost equally in the axial direction from the center side to the outer circumferential side, and the distance between each wrap portion and the opposing end plate increases. The thrust direction gap can be made substantially uniform from the center side to the outer circumferential side of each wrap portion.

In addition, as the temperature of each lap increases, the liquid in the cylinder chamber thermally expands, and the piston slides within the cylinder due to the thermal expansion of the liquid, so the orbiting scroll moves in the axial direction according to the thermal expansion of each lap. The thrust direction gap between each wrap portion and the opposing end plate can be adjusted to be substantially constant.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.
An example in which the present invention is used as an oil-free air compressor will be explained. In the embodiment, the same elements as those in the prior art described above are given the same reference numerals, and their explanations will be omitted.

In the figure, reference numeral 21 indicates an orbiting scroll according to the present embodiment, and the orbiting scroll 21 is substantially similar to the orbiting scroll 6 described in the prior art, and includes an end plate 22 and a thin winding provided upright on the bottom 22A of the end plate 22. The wrap portion 23 is formed integrally with the mirror plate 22 from cast iron or the like as a material with a small coefficient of thermal expansion, as shown in FIG. A proximal end portion 23A as a lug portion, and a wrap portion on the other side that is fixed to the distal end side of the proximal end portion 23Δ over the entire circumference and made of an aluminum alloy or the like as a material with a large coefficient of thermal expansion. The wrap portion 23 is formed in a two-layer structure in the height direction of the wrap portion 23 with the tip portion 23B.For reasons described later, the portion of the tip portion 23B in the wrap portion 23 increases from the center side to the outer circumferential side. is gradually increasing.

That is, during operation of the compressor, the heat of compression in the compression chamber 6 on the center side is higher than that in the compression chamber 16 on the outer circumference side, and the heat of compression from the center side (winding start end) to the wrap part 23, etc. 1] on the outer circumference side ( Since a temperature gradient occurs in the radial direction toward the end of the winding, the temperature rise ΔT1 on the center side of the wrap portion 23 increases by the temperature rise ΔT1 on the outer peripheral side depending on the distance from the center side to the outside in the radial direction.
Therefore, for example, if the thermal expansion Δh1 on the center side of the wrap portion 23 and the thermal expansion Δh2 on the outer peripheral side, Δh+ = (h+A・αA+hlB・αB)・△T1
...(2) △h2-(h2A・α+)'12[l・all)・△
T2...(3) However, α Thermal expansion coefficient α6 of the proximal end 23A, Thermal expansion coefficient h of the distal end 23B IA: Height dimension h111 of the proximal end 23A on the center side:
Height dimension h2A of the center side tip portion 23B: Height dimension h2a of the outer circumference side proximal end portion 23A: Outer circumference side tip portion 23B
is calculated as the height dimension. Therefore, in this embodiment, each thermal expansion Δh1. The relationship of Δ1]2 is determined as follows: Δh,=Δ11□ (4) By determining the ratio of the tip portion 23B to the wrap portion 23 from the temperature gradient that occurs depending on the distance from the center. During compression, the wrap portion 23 thermally expands almost equally as a whole from the center side to the outer circumference side, so that the thrust direction gap δ becomes almost uniform from the center side to the outer circumference side of the wrap portion 23. It's happening.

Reference numeral 25 indicates a fixed scroll according to the present embodiment, and the fixed scroll 25, like the end plate 26 and the wrap portion 23 of the orbiting scroll 21, has the relationship of equations (2), (3), and (4) above, and is heat-resistant. Although it is composed of a wrap portion 27 that stands up in a spiral shape from a base end portion 27A with a small coefficient of expansion and a tip portion 27B with a large coefficient of thermal expansion, a support plate 28 and an annular plate 29, the annular plate 29 A cylinder chamber 31, which will be described later, is formed around the entire circumference on the inner peripheral side.

Reference numeral 30 denotes a thrust receiving portion, and the thrust receiving portion 30 includes a cylinder chamber 31 formed in a bottomed annular shape located on the inner peripheral side of the annular plate 29, and an injection port 31. Silicon oil 32 as a liquid filled through A, and an annular piston 3 slidably provided in the cylinder chamber 31.
It is composed of 3. And the thrust receiving part 30
Due to the reason explained later, during the compression action, the orbiting scroll 2
1 while receiving the load in the thrust direction of the wrap portion 23.
27 thermally expands, the orbiting scroll 21 is forced toward the thrust receiving portion 3B of the front casing 3, and the thrust direction gap δ1 is adjusted to be substantially constant.

34,. 34 is a seal member such as an O-ring that is fitted to the inner and outer circumference of the annular piston 33 to keep the inside of the cylinder chamber 31 liquid-tight; 35 is fitted to the injection hole [131A] of the cylinder chamber 31, and the silicone oil 32 is This is a plug member that prevents leakage.

Here, the thrust receiving part 30, each wrap part 23.2
When thermal expansion △1] (△h = △1] 1 - Δh2) occurs in 7, the silicone oil 32 thermally expands by this thermal expansion △h, slides the piston 33, and moves the orbiting scroll 21 to the front side. In order to keep the thrust direction gap δ1 almost constant on the side of the thrust receiving part 3B of the casing 3, however, ■: Initial volume S of the silicone oil 32 Cross-sectional area αC of the cylinder chamber 31: Thermal expansion of the silicone oil 32 Rate △11 Thermal expansion △T3 of the tube part 23.27: From the relationship of the temperature rise of the silicone oil 32, the initial volume of the silicone oil 32 (filling amount),
Thermal expansion coefficient α. etc. to be determined.

The scroll type air compressor according to this embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, each wrap portion 23,27 of the orbiting scroll 21 and the fixed scroll 25 has a small thermal expansion coefficient α.
Base end portions 23A and 27A having □ and a large coefficient of thermal expansion α
8.

27B to form a two-layer structure in the height direction of each wrap portion 23.27, as described in (2) and (3) above.

The wrap portion 23.2 has the relationship shown in equation (4).
7, the ratio of the tip portions 23B and 27B to 7 is determined according to the temperature gradient that occurs during the compression action. Therefore, during the compression action, each wrap portion 23, 27 is axially moved as a whole from the center side to the outer circumferential side. Thermal expansion is approximately equal, thereby reducing the thrust direction gap δ1 to the lap portion 23.2.
7 can be almost uniform from the center side to the outer circumference side, and not only can the galling phenomenon be reliably prevented, but also the pressure leakage in the compression chamber 16 can be prevented even when the compressor is operated at a low pressure below the rated pressure. This can be effectively prevented and the start-up performance and compression efficiency can be improved without being affected by changes in temperature or operating conditions.

In addition, since the thrust receiving part 30 is constituted by the cylinder chamber 31, silicone oil 32, and piston 33, which have a relationship as shown in equation (5) above with respect to the thermal expansion Δh of the wrap part 23.27, the wrap Thermal expansion of part 23.27 △
The orbiting scroll 21 can be biased toward the thrust receiver 3B side of the front casing 3 according to h, and this thermal expansion Δh can be absorbed to adjust the thrust direction gap δ1 to be almost constant, thereby widening the compression efficiency, durability, etc. In addition to being stable over a temperature range, by adjusting the amount of silicone oil 32 filled into the cylinder chamber 31, the thrust direction gap δ in the initial state can be finely adjusted. The efficiency of compressor assembly and adjustment work can be greatly improved.

In the above embodiment, the wrap portions 23.27 are made of base end portions 23A, 2 made of cast iron or the like as a material with a small coefficient of thermal expansion.
7A, and is fixed to the distal side of the base end portions 23A and 27A,
The tip portion 23B is made of an aluminum alloy or the like as a material with a large coefficient of thermal expansion.

27B, but the present invention is not limited to this. For example, ceramics or other alloys may be used as a material with a small coefficient of thermal expansion, and a heat-resistant resin material may be used as a material with a large coefficient of thermal expansion. Alternatively, the proximal end portion may be formed from a material with a high coefficient of thermal expansion as the other side wrap portion, and the distal end portion may be formed from a material with a low coefficient of thermal expansion as the one side rubber portion.

Further, in the embodiment, the proximal end 2 of the wrap portion 23.27
3A and 27A have been described as being formed integrally with the head plate 22.26 from cast iron or the like, but instead of this, the lap portion 23
．． 27 and the end plates 22 and 26 may be formed as separate members, and the two may be fixed using a fixing means such as welding.

Further, in the embodiment described above, the thrust receiving part 30 is provided on the annular plate 29 of the fixed scroll 25, but the present invention is not limited to this. , a thrust receiver made of a piston may be provided.

Furthermore, in the embodiment, the cylinder chamber 31 is formed by the annular plate 29.
Although the cylinder chamber 31 has been described as having an annular piston 33 slidably provided within the cylinder chamber 31, for example, a cylinder chamber having a bottomed cylindrical shape may be formed in an annular manner. Two or more pistons may be formed on the inner peripheral side of the plate 29, spaced apart in the circumferential direction, and a piston may be slidably provided in each cylinder chamber.

On the other hand, in the embodiment described above, silicone oil was used as an example of the liquid, but other oils or the like may be used as the liquid instead.

Further, in the above embodiments, a non-lubricated air compressor is used as an example of a scroll type fluid gas, but the present invention is not limited to this, and the present invention is not limited to this, but can be applied to other scroll type fluid machines such as a lubricated type or a semi-lubricated type. Alternatively, it can be connected to a vacuum container and used as a vacuum pump, and it can also be applied to a refrigerant compressor.

[Effect of the Invention 1] As detailed above, according to the present invention, each wrap portion of the orbiting scroll and each wrap portion of the fixed scroll includes a one-side wrap portion made of a material with a small coefficient of thermal expansion and a material with a large coefficient of thermal expansion. It is formed into a two-layer structure in the axial direction from the other side wrap part made of material, and the ratio of the other side wrap part to each wrap part increases from the center side to the outer circumferential side of each wrap part. , each wrap part of both scrolls thermally expands in the - side wrap part and the other side wrap part in accordance with the temperature change generated from the center side to the outer circumference side due to the compression heat of the compression chamber, etc., and the temperature increases from the center side to the outer circumference side. As a whole, each wrap section thermally expands almost equally in the axial direction, and the thrust direction gap between each wrap section and each opposing mirror plate is made almost uniform from the center side to the outer circumferential side of each wrap section. This makes it possible to reliably prevent the galling phenomenon and improve the start-up performance, compression efficiency, and durability of the scroll-type fluid machine.

Further, either the casing or the fixed scroll includes a cylinder chamber, a liquid filled in the cylinder chamber, and a piston that is slidably provided in the cylinder chamber and receives the load in the thrust direction. Since a thrust receiving part consisting of The orbiting scroll can be displaced in the axial direction accordingly, and the gap in the thrust direction between each wrap portion and the opposing end plate can be adjusted to be substantially constant over a wide temperature range.

[Brief explanation of the drawing]

1 and 2 relate to an embodiment of the present invention; FIG. 1 is a vertical sectional view showing an enlarged main part of a scroll air compressor according to the present embodiment, and FIG. FIGS. 3 and 4 are longitudinal sectional views showing an enlarged view of the wrap portion, etc., relate to the prior art, FIG. 3 is a longitudinal sectional view showing a scroll type air compressor according to the prior art, and FIG. 4 is the wrap portion, etc. FIG. 1...Casing, 3B...Thrust receiver, 16.
...Compression chamber, 21...Orbiting scroll, 22.26.
...End plate, 23.27...Wrap part, 23A, 27A
... Base end part (- side lap part), 23B, 27B...
Tip part (other side wrap part), 25... fixed scroll,
30... Thrust receiving part, 31... Cylinder chamber, 32
...Silicon oil (liquid), 33...Piston.

Claims (2)

[Claims] (1) A casing, an orbiting scroll that is rotatably provided in the casing and has a spiral wrap portion erected on an end plate, and an orbiting scroll that is fixed to the casing facing the orbiting scroll and that is attached to the end plate. In a scroll-type fluid machine, each of the orbiting scroll and the fixed scroll has a fixed scroll provided with a spiral wrap section that overlaps with the wrap section of the scroll to form a plurality of compression chambers. A two-layer structure is formed in the axial direction by one side wrap made of a material with a small coefficient of thermal expansion and the other side wrap made of a material with a large coefficient of thermal expansion, and the proportion of the other side wrap in each wrap is set as follows. A scroll-type fluid machine characterized in that the number of wraps increases from the center side to the outer circumferential side of each wrap portion. (2) Either the casing or the fixed scroll includes a cylinder chamber, a liquid filled in the cylinder chamber, and a piston that is slidably provided in the cylinder chamber and receives the load in the thrust direction. 2. The scroll fluid machine according to claim 1, further comprising a thrust receiving portion comprising: