JPH05113181A - Scroll fluid compressor - Google Patents

Abstract

(57) [Summary] [Purpose] The machine work can be facilitated and productivity can be improved, the centrifugal force of the drive unit can be reduced during high-speed operation, and the durability is excellent and sliding loss is low. Provide a reliable scroll fluid compressor. In a scroll fluid compressor, a fixed scroll is formed of an iron-based material, and an orbiting scroll is prepared by a powder metallurgy method using aluminum powder containing 20 wt% to 35 wt% of silicon. Particle size of silicon crystals dispersed in 10 μm
It is formed by a forging method using an aluminum alloy base material of m or less, or at least an orbiting scroll containing 1 wt% to 3 wt% of phosphorus in which 1 wt% to 20 wt% of a silicon compound is dispersed. It is formed using an aluminum alloy having a surface layer made of a nickel alloy containing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll fluid compressor having excellent durability.

[0002]

2. Description of the Related Art A conventional scroll fluid compressor has a structure in which a spiral wrap is fixed to an end plate and a fixed scroll and an orbiting scroll are meshed with each other. By orbiting the orbiting scroll so that both wraps come into contact with each other, the compression chamber formed by both scrolls gradually decreases toward the center, and the fluid sucked from the outer peripheral portions of both wraps is compressed to the central portion. Is discharged from the discharge port.

As a material for the fixed scroll and the orbiting scroll which constitute such a compression mechanism of the scroll fluid compressor, an iron system mainly composed of cast iron or an iron system for the fixed scroll is cast for the orbiting scroll. There is one using an aluminum system.

[0004]

However, when the compression mechanism section is formed by the combination of such materials, the following problems occur.

1) When both the fixed / orbiting scroll and the iron-based material are combined, if the iron-based material having a large specific gravity is used for the orbiting scroll,
Since the centrifugal force during operation is too large, the bearing load increases and sliding loss also increases. In particular, during high-speed operation, the centrifugal force becomes extremely large, so that the main shaft and the bearing are heavily worn and lack durability. In order to improve the accuracy of the scroll blade, it is necessary to perform precision machining of the mounting surface, sliding surface, etc., but because iron-based materials have low machinability, the machining is extremely difficult and it is difficult to improve productivity. Met.

2) When an iron-based material is combined with a fixed scroll and an orbiting scroll is combined with an aluminum-based material produced by a casting method, the aluminum-based material produced by the casting method and the iron-based material have remarkably different thermal expansion coefficients. Had to be increased in clearance, resulting in performance degradation. To improve the accuracy of the scroll blade, it is necessary to perform precision machining of the mounting surface, sliding surface, etc., but aluminum-based materials produced by the casting method, especially aluminum alloys containing silicon, are difficult to cut, so It has been difficult to improve the mass productivity of scroll fluid compressors due to shortened life and reduced cutting accuracy due to tool wear. Among aluminum-based materials, aluminum-based alloys have inferior hardness compared to cast iron-based materials. Therefore, when the load is high, the mating material is abraded while silicon particles in the aluminum-based alloy float, and the critical PV value is small. There was a problem of becoming.

The present invention has been made in order to solve the above-mentioned problems, and can facilitate the machining and improve the productivity, and can reduce the centrifugal force of the drive unit during high-speed operation, and An object of the present invention is to provide a highly reliable scroll fluid compressor having excellent durability and low sliding loss.

[0008]

In the scroll fluid compressor of the present invention, a spiral wrap of an orbiting scroll is engaged with a spiral wrap of a fixed scroll, and the orbiting scroll is rotated with respect to the fixed scroll. In a scroll fluid compressor configured to move,
The fixed scroll is formed of an iron-based material, and the orbiting scroll is prepared by powder metallurgy using an aluminum powder containing 20% by weight to 35% by weight of silicon, and at least the silicon crystals dispersed on the surface are prepared. Is formed by forging method using an aluminum alloy base material having a particle diameter of 10 μm or less,
Or at least 1% by weight of the orbiting scroll
~ 1% by weight with 20% by weight of silicon compound dispersed ~
It is characterized by being formed using an aluminum alloy having a surface layer made of a nickel alloy containing 3% by weight of phosphorus.

The iron-based material used for the fixed scroll relating to the first scroll fluid compressor of the present invention includes:
Those used in ordinary hermetic fluid compressors are suitable. For example, there is a material such as FC25 (JIS standard, G5501).

The orbiting scroll relating to the first scroll fluid compressor of the present invention uses, as a base material, an aluminum alloy prepared by powder metallurgy from an aluminum powder containing 20% by weight to 35% by weight of silicon. The content of silicon in the aluminum alloy is set to 20% by weight to 35% by weight,
This is because if it is less than 20% by weight, the thermal expansion coefficient becomes too large, and if it exceeds 35% by weight, the machinability becomes extremely difficult.

An aluminum alloy containing 5% by weight or less of a transition metal such as iron, copper or nickel as a usual impurity is also within the permissible range of the present invention.

Further, the powder metallurgy method is suitable for the present invention because the content of silicon can be increased as compared with the casting method. As a method for producing the metal powder, any method of producing from a solid phase, a liquid phase or a gas phase can be used. Using the powder thus obtained, a lumped billet serving as a base material of an aluminum alloy is produced by, for example, an extrusion method.

Then, using this billet, the particle size of silicon crystals dispersed in at least the surface layer was 10 μm.
An orbiting scroll having a diameter of m or less is manufactured by a forging method.

The forging method is used because small hard points made of silicon crystals having a uniform particle size and uniformly dispersed are easily formed on the surface of the aluminum alloy material. The adhesion between the hard point portion made of silicon crystal and the aluminum-silicon matrix is large, and even when sliding with FC25, the small hard point made of silicon crystal falls off from the aluminum-silicon matrix and causes abrasion of the sliding surface. Therefore, a material having a low coefficient of friction and high wear resistance can be obtained by the forging method.

On the other hand, in the aluminum alloy produced by the casting method, the silicon crystals in the aluminum-silicon matrix have a variation in particle diameter, the adhesion between the large particle portion and the aluminum-silicon matrix is small, and the particles fall off by sliding ( That is, it is easy to wear, and in addition, particles that have fallen off enter the sliding surface and often cause secondary wear.

The particle size of the silicon crystal dispersed in at least the surface layer is 10 μm or less when the particle size is 10 μm or less.
This is because the adhesion strength of the aluminum-silicon matrix is reduced if it exceeds.

The orbiting scroll used in the second scroll fluid compressor of the present invention comprises a nickel alloy containing 1% to 3% by weight of phosphorus in which 1% to 20% by weight of a silicon compound is dispersed. It is characterized by being formed using an aluminum alloy having a surface layer.

The nickel alloy containing 1% by weight to 3% by weight of phosphorus may be any method as long as it can add phosphorus to nickel, but the electroless plating method has few pinholes. It is particularly preferable because even a complex shape such as a scroll can be uniformly formed with an arbitrary thickness.

A silicon compound dispersed in a nickel alloy containing phosphorus is added to improve wear resistance and seizure resistance. Particularly preferable silicon compounds include silicon carbide and silicon nitride.

The content of phosphorus in the nickel alloy is 1% to 3% by weight, and the silicon compound to be dispersed is 1% by weight.
The reason why the content is set to 20% by weight is that the wear state of the surface layer was examined when the phosphorus content and the silicon compound content were changed, and the above range showed the best wear state. .. The measurement results are shown in Table 1. The measurement method is
Using a friction wear tester having a blade 13 and a disk 14 shown in FIG. 2 in which a surface layer in which the contents of phosphorus and a silicon compound are changed is formed on an aluminum alloy (AC8C) and the mating material is cast iron (FC25). went. For the evaluation, the surfaces of the surface layer and the mating material were observed with a scanning electron microscope.

[Table 1] Further, the results of examining changes in the surface layer thickness and the seizure value depending on the composition of the optimum range using the above friction and wear tester are shown in FIG.
However, according to this, it is understood that when the surface layer thickness is 2 μm or more, a seizure resistance value sufficient for the design of the scroll fluid compressor can be obtained. Therefore, 1% by weight
~ 1% by weight with 20% by weight of silicon compound dispersed ~
The thickness of the surface layer made of a nickel alloy containing 3% by weight of phosphorus is preferably 2 μm or more.

As the material of the fixed scroll relating to the second scroll fluid compressor of the present invention, the material used for a usual hermetic fluid compressor can be used. For example,
A material such as FC25 (JIS standard, G5501) can be used.

[0022]

With the structure of the first scroll fluid compressor according to the present invention, the orbiting scroll is made of an aluminum base material so that the orbiting scroll can be reduced in weight and the centrifugal force of the orbiting scroll can be reduced. It is possible to suppress wear of sliding parts during high-speed operation.

Moreover, by forming the base material by the powder metallurgy method, the amount of silicon added can be increased as compared with the casting method, and the coefficient of thermal expansion of the base material can be reduced. As a result, the difference in thermal expansion coefficient between the sliding material and the iron-based material becomes small, the clearance between both scrolls can be set small, and the leakage of compressed gas can be minimized.

Further, since the spiral wrap portion is formed by the forging method, it is not necessary to carry out machining and shaping by cutting as in the conventional casting method, and the final dimension can be obtained only by finishing. Therefore, the machining amount can be significantly reduced. That is, in the manufacture of the orbiting scroll, mass productivity can be significantly improved, and in addition, the cost of the orbiting scroll can be reduced by greatly reducing the amount of processing.

Further, by adopting the structure of the second scroll fluid compressor of the present invention, the surface of the orbiting scroll is made to disperse a silicon compound such as silicon carbide or silicon nitride in a nickel alloy containing phosphorus. By using the surface layer having high hardness, wear resistance and apparent hardness are increased, and seizure resistance of the orbiting scroll is improved.
Therefore, it is possible to suppress wear of the sliding portion during high-speed operation.

Since the surface layer of the nickel alloy containing phosphorus can be formed by the electroless plating method or the like, it is possible to form a film having a uniform thickness on the surface of the orbiting scroll having a small number of pinholes and a complicated shape. ..

[0027]

Embodiments of the present invention will now be described in detail with reference to the longitudinal sectional view showing the structure of the scroll fluid compressor shown in FIG. Example 1 The inside of the closed container 1 is divided into two spaces communicated by a frame 2. A circular opening 2a is formed in the center of the frame 2, and the main shaft 3 is rotatably supported in the opening 2a. A rotor 4 is attached to the lower part of the main shaft 3, and a stator 5 is press-fitted into the hermetically sealed container 1 at the outer peripheral portion thereof.

Crankshaft portion 3 formed on the upper portion of the main shaft 3
The orbiting scroll 6 is rotatably supported on a,
A fixed scroll 7 is fixed to the outer peripheral protrusion 2b of the frame 2. The orbiting scroll 6 and the fixed scroll 7 used here have a structure in which spiral wraps 6b and 7b are provided upright on opposite plate surfaces of the end plates 6a and 7a, and fixed to the wrap 6b of the orbiting scroll 6. When the wraps 7b of the scroll 7 are engaged with each other, the compression chamber 12
Is formed. Between the orbiting scroll 6 and the frame 2, for example, an Oldham ring 8 is provided as a mechanism for preventing rotation of the orbiting scroll 6 during the orbiting motion.

A discharge port 9 for discharging the compressed gas into the closed container 1 is formed at the center of the fixed scroll 7. In addition, the suction gas is supplied to both scroll wraps 6b,
A suction pipe 10 leading to the outer peripheral portion of 7b and a discharge pipe 11 guiding the compressed gas to the outside are attached to penetrate the sealed container 1.

The orbiting scroll 6 according to the first embodiment is formed of an aluminum alloy material on which a base material is formed by a powder metallurgy method and a vortex blade is formed by a forging method.

The orbiting scroll 6 is formed by an air atomizing method, and powder of aluminum and silicon containing 20% by weight to 35% by weight of silicon is extruded to form a lumped billet, and then the billet is spirally wrapped. After being inserted into a scroll-shaped metal mold having, a forging method was formed into a scroll shape. After forming into a scroll shape, the sliding surface was cut to improve accuracy. By molding the aluminum alloy material by a forging method, a large number of small hard points made of silicon crystals having a uniform particle diameter of about 7 μm are uniformly dispersed and formed. The above surface metallographic structure is shown in FIG. 4 in comparison with an aluminum alloy material (JIS.AC8C) produced by a casting method.

In Example 1, the orbiting scroll 6 was formed with the base material by the powder metallurgy method and the vortex blade was formed by the forging method.
An aluminum alloy material containing 30 wt% of silicon was used, and the fixed scroll 7 was made of cast iron FC25.

The orbiting scroll 6 and the fixed scroll 7
As a result of constructing a scroll fluid machine with a compression function by using the PC and performing actual machine tests, good wear resistance and low vibration were obtained under the conditions of high load (high load) operation and high speed operation (150 Hz). ..

Using the friction and wear tester shown in FIG. 2, the material combination of Example 1 and the iron-based material / iron-based material (FC2
5 to FC25) (Comparative Example 1) and aluminum alloy-based material / iron-based material (AC8C to FC25) by the casting method.
When the relationship between the dynamic friction coefficient and the load (contact pressure) of the comparative example including the combination of (Comparative example 2) was evaluated at three levels of sliding speed, the results shown in FIG. 5 were obtained. Here, it was found that in Example 1, the value of the dynamic friction coefficient was kept small even under a high load, and seizure did not occur even under a high load. on the other hand,
The comparative example has a larger coefficient of dynamic friction than the low load region, and
It was found that seizure occurs at a lower load than that of.

Therefore, according to the structure of the first embodiment, it is possible to adopt the aluminum alloy type material for the orbiting scroll, and because of its light weight, low linear expansion coefficient and low processing cost, it is It is possible to obtain a scroll fluid compressor having a small sliding loss, high-speed operation, small leakage of compressed gas between sliding surface portions, high efficiency, excellent mass productivity, and an inexpensive orbiting scroll.

The present invention is not limited to the above-described first embodiment, and various modifications can be carried out. For example, in the first embodiment, the product of the present invention is applied to the scroll fluid machine having the compression function, but the product of the present invention can also be applied to the scroll fluid machine having the expansion function. Example 2 and Example 3 FIG. 6 is a vertical cross-sectional view showing a schematic configuration of the orbiting scroll of Example 2 and Example 3.

Surface layer 1 containing 15% by weight of silicon carbide and a nickel alloy having a phosphorus content of 2% by weight as a main component
A scroll fluid compressor identical to that of Example 1 was produced except that the orbiting scroll 5 made of aluminum alloy 16 (AC8C) formed by electroless plating was used as Example 5 (Example 2).

Further, a surface layer 15 containing nickel nitride having a phosphorus content of 2% by weight as a main component in which 5% by weight of silicon nitride is dispersed is formed by an electroless plating method on an aluminum alloy 16 ( The same scroll fluid compressor as in Example 1 was produced except that the orbiting scroll 6 made of AC8C) was used (Example 3).

A scroll fluid machine having a compression function was constructed using the orbiting scroll 6 and the same actual machine test as in Example 1 was conducted. As a result, in both Examples 2 and 3, high load (high load) operation and high speed operation were performed. Good wear resistance and low vibration were obtained under the operating condition (150 Hz).

Further, the relationship between the dynamic friction coefficient and the load (contact pressure) of the material combinations of Examples 2 and 3 and the above-mentioned Comparative Examples 2 and 3 was evaluated using the friction and wear tester shown in FIG. The result shown in FIG. 5 was obtained. From FIG. 5, it can be seen that according to Examples 2 and 3, the frictional force is small and the seizure value is high.

Therefore, according to the structure of the embodiment, it is possible to adopt the aluminum alloy material for the orbiting scroll, and because of its light weight, low linear expansion coefficient, and low processing cost, it is more slidable than the conventional one. It is possible to obtain a scroll fluid compressor that has a low dynamic loss, enables high-speed operation, has a small leak of compressed gas between sliding surface portions, has high efficiency, is excellent in mass productivity, and has an inexpensive orbiting scroll.

[0042]

In the scroll fluid compressor of the present invention, the fixed scroll is formed of an iron-based material, and the orbiting scroll is formed by a forging method using an aluminum alloy base material prepared by a powder metallurgy method. Processing was easy and productivity could be improved, and the influence of centrifugal force of the drive unit could be suppressed. Further, since the orbiting scroll is formed by using an aluminum alloy having a surface layer formed by dispersing a silicon compound in a nickel alloy containing phosphorus,
The wear resistance and seizure resistance were also improved.

As a result, a scroll fluid compressor having excellent durability, low drive loss, high reliability, and low cost was obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a scroll fluid compressor according to a first embodiment.

FIG. 2 is a diagram showing a friction and wear tester.

FIG. 3 is a diagram illustrating changes in surface layer thickness and seizure value in Example 2.

4 is a metallographic photograph showing the metallographic structure of Example 1. FIG.

FIG. 5 is a diagram showing a relationship between a dynamic friction coefficient and a surface pressure (load) in Examples and Comparative Examples.

FIG. 6 is a vertical cross-sectional view showing the structure of an orbiting scroll according to Embodiments 2 and 3.

[Explanation of symbols]

1 ...... closed container, 2 ......... frame, 2a ......... circular opening, 2b ......... peripheral protrusion, 3 ......... main shaft, 3a ...
...... Crankshaft part, 4 ......... Rotor, 5 ......... Stator, 6 ......... Orbiting scroll, 7 ......... Fixed scroll, 6a and 7a ......... End plate, 6b and 7b ...
Swirl-shaped wrap, 8 ... Oldham ring, 9 ... Discharge port, 10 ... Suction pipe, 11 ... Discharge pipe, 12
……… Compression chamber, 13 …… Blade, 14 …… Disk,
15 ... Surface layer, 16 ... Aluminum alloy.

Claims (2)

[Claims] 1. A spiral scroll wrap of a fixed scroll,
In a scroll fluid compressor configured to engage a spiral wrap of an orbiting scroll and to orbit the orbiting scroll with respect to the fixed scroll, the fixed scroll is formed of an iron-based material, and An orbiting scroll was prepared by a powder metallurgical method using aluminum powder containing 20% by weight to 35% by weight of silicon, and an aluminum alloy base material having at least 10 μm or less of silicon crystals dispersed on the surface was used. And a scroll fluid compressor formed by a forging method. 2. A spiral wrap of a fixed scroll,
In a scroll fluid compressor configured to engage a spiral wrap of an orbiting scroll and to orbit the orbiting scroll with respect to the fixed scroll, at least 1 to 20% by weight of the orbiting scroll.
A scroll fluid compressor formed by using an aluminum alloy having a surface layer made of a nickel alloy containing 1% by weight to 3% by weight of phosphorus in which the silicon compound is dispersed.