JPH09119382A - Scroll member for compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll member which improves a baking property of an anode oxide film and flattens the surface thereof. SOLUTION: A fixed scroll member 10 and a movable scroll member 20 are made of aluminum containing Si and an anode oxide film 23 is formed on the surfaces of the scroll members 10, 20 by electrolytic solution comprising a compound containing anion having complexing characteristic, organic acid containing an oxygen acid anion, and a halide. The halide selectively dissolves inclusions such as Si, other additive metals and intermetallic composite with the oxygen acid anion and removes them from the anode oxide film 23. The compound containing anion having complexing characteristic flattens the anode oxide film 23.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a scroll member for a compressor used in a compressor such as an air conditioner.

[0002]

2. Description of the Related Art Conventionally, scroll compressors are provided with a pair of spiral scroll members that slide in contact with each other, and the sliding surfaces of the spiral scroll members are protected from seizure and scratches. In order to prevent this, various surface treatment methods have been proposed. For example, Japanese Patent Publication No. 63-3299
In the surface treatment method proposed in Japanese Unexamined Patent Publication No. 2 (1994) "Scroll type compressor for automobile air conditioning", an anodic oxide film is formed on only one sliding surface of a pair of spiral scroll members, and the scroll member of the other scroll member is formed. The sliding surface is the aluminum base.

Thus, by forming the anodic oxide film on only one sliding surface, the sliding surface of one scroll member and the sliding surface of the other scroll member slide while contacting each other. When doing, the other scroll member can be deformed and escaped. As a result, it is possible to prevent the seizure of the sliding surface that occurs when both the pair of scroll members are left as the base materials. Further, it is possible to eliminate scratches on the anodic oxide film that occur when both the pair of scroll members are subjected to the anodic oxide film treatment.

On the other hand, Japanese Unexamined Patent Publication No. 6-167243, "Sliding member for engine cylinder", discloses an invention whose purpose is to treat Si contained in an aluminum base material. In this method, when an aluminum material containing 8 to 12% of Si is anodized by an ordinary direct current electrolysis in sulfuric acid, Si inhibits the passage of plating current, resulting in only a thin and soft film. This is to solve the problem of not being able to do so, and employs a current reversal method to crush Si, improve current flow, and obtain a thick hard film.

[0005]

By the way, in recent years, from the viewpoint of the global environment, there has been a demand for a substitute for the refrigerant CFCs used in air conditioners for automobiles. Therefore, the output of scroll type compressors for air conditioning has to be increased. There is a demand for higher strength of the scroll member. Further, according to the above, it is disclosed that Si can be crushed, electric current can be improved, and a thick hard coating can be obtained. However, in this method, acicular Si can be crushed to be finer. , Si particles remain in the base material and the anodic oxide film. Therefore, the oxide film has a problem of seizure, which is not preferable.

Therefore, an object of the present invention is to provide a technique of a scroll member for a compressor which has high strength and is excellent in seizure property.

[0007]

In order to solve the above-mentioned problems, the first aspect of the present invention is directed to a scroll member for a compressor, which compresses fluid by relatively rotating a pair of spiral scroll members. The scroll member of Si
And an anodized film is formed on the surface of the spiral scroll member with an electrolyte solution containing a compound containing a complexing anion, an organic acid containing an oxygenate anion, and a halide. Is characterized by. The “complexing ability” means the ability to form a complex by coordinating with a metal ion as a ligand. The term "complex" means that when an atom of a metal or a metal-like element is a central atom and another atom or atomic group, that is, a ligand is bonded to form a single atomic group, the atomic group is called a complex. "Anion" means an anion.

The compound containing an anion having a complexing property is at least one selected from sodium hydrogen phosphate and trisodium phosphate, and the organic acid containing the oxygen acid anion is sodium citrate. , Sodium tartrate and sorbitol, and the halide is at least one selected from potassium fluoride and sodium fluoride.

As described above, when anodization is performed using the electrolytic solution consisting of the above, a desired anodized film can be formed on the surface of the scroll member made of aluminum containing Si by the following action. That is, in the electrolyte ~
Have the following effects. Oxygen acid anions supply OH − ions to the anode and improve the efficiency of film formation. The halide selectively dissolves inclusions such as Si, other added metals, and intermetallic compounds together with the oxygenate anion, and removes them from the anodic oxide film. The compound containing a complexing anion serves to flatten the anodized film. That is, if the outer surface of the anodic oxide film is uneven during formation, the compound containing the anion is thickly attached to the concave portion and thinly attached to the convex portion. Apparently
The elution rate of Al ions is slow in the concave portion and high in the convex portion, so that the outer surface of the anodic oxide film becomes flat.

The specific compounds (1) to (3) and their preferable concentration ranges are as follows. Compound containing anion having complexing property; preferred compound; sodium hydrogen phosphate, trisodium phosphate preferred concentration; sodium hydrogen phosphate is 0.2 to 0.5 mol, trisodium phosphate is 0.2 to If it is less than 0.4 mol lower limit, the rate of formation of the anodic oxide film is, for example, 0.
It becomes as slow as 01 μm / min and the productivity deteriorates. Also, if it exceeds the upper limit, it becomes supersaturated and precipitates freely and becomes meaningless.

Organic acids containing oxygenate anions; preferred compounds; sodium citrate, sodium tartrate,
Sorbitol suitable concentration; sodium citrate is 0.1 to 0.75 mol Sodium tartrate is 0.1 to 0.55 mol Sorbitol is 0.25 to 0.75 mol If the upper limit is exceeded, burning will occur and the film growth will stop.

Halides; preferred compounds; potassium fluoride, sodium fluoride suitable concentrations; potassium fluoride is 0.1 to 0.75 mol; sodium fluoride is 0.1 to 0.75 mol; If the remaining amount of the alloy component becomes excessive and if the upper limit is exceeded, the growth of the film will stop.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a partial sectional view of a compressor incorporating a scroll member for a compressor according to the present invention.
The casing 2, the fixed scroll member 10 fixed in the casing 2, the rotating scroll member 20 slidably engaged with the fixed scroll member 10, the eccentric shaft 30 rotatably connected to the movable scroll member 20, and the like. Consists of. The casing 2 includes a suction port 3 and a discharge port 4. The suction port 3 and the discharge port 4 are formed at the ends of the casing 2. Further, 35 is a pulley provided at the left end of the eccentric shaft 30, and 36 is a bearing.

FIG. 2 is an exploded view of the scroll member for a compressor according to the present invention. The fixed scroll member 10 comprises a spiral scroll portion 11 and a disk portion 12. The movable scroll member 20 is composed of a spiral scroll portion 21 and a disk portion 22, and an anodized film 23 described later is formed on the surface of the spiral scroll portion 21 and the surface of the disk portion 22, respectively. As a result, an oxide film is formed on the sliding surface between the fixed scroll member 10 and the movable scroll member 20.

The movable scroll member 20 has a bearing portion 24 formed on the eccentric shaft 30 side of the disk portion 22,
The eccentric shaft 30 via the bearing 36 in the bearing portion 24
The eccentric part 31 is rotatably supported. The eccentric portion 31 has a center C ₂ from the center C ₁ of the main shaft portion 32 of the eccentric shaft 30 to L
It is offset only. Then, the center C ₁ of the main shaft portion 32 is supported coaxially with the fixed scroll member 10,
The center C ₂ of the eccentric portion 31 is supported coaxially with the movable scroll member 20. The disk portion of the fixed scroll member 10 has a suction port 14 and a discharge port 15.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1, showing a state in which the fixed scroll member 10 and the movable scroll member 20 are slidably engaged. In this case, the scroll unit 1
1 and the scroll portion 21 are engaged with each other to form a hermetically sealed space 28, 28.
To form Further, the casing 2 and the scroll member 1
A suction space 29 is formed with the outer peripheral surfaces of 0 and 20, and the suction hole 14 for sucking air into the suction space 29 is formed in the disk portion 12.

The operation of the compressor scroll member described above will be described below. First, the pulley 35 shown in FIG. 1 is rotated to rotate the eccentric shaft 30 about the main shaft portion 32, and the eccentric portion 31 and the movable scroll member 20 are connected to the main shaft portion 32.
Rotate about the center C ₁ (see FIG. 2) as an axis. FIG.
(A) ~ (d) is an operation explanatory view of a scroll member for a compressor according to the present invention. In the figure, the movable scroll member 20 revolves around C ₁ to the axis. (A) is a suction space 29
2 shows a state in which the air introduced from the above is sealed in the sealed spaces 28, 28.

[0018] (b) it is in the clockwise direction as an axis center C ₁ of the center C ₂ of the movable scroll member 20 from (a) 00
° Indicates a revolved state. As a result, the center C ₂ of the movable scroll member 20 moves to a position above the center C ₁ to reduce the volume of the closed spaces 28, 28 and compress the air in the closed spaces 28, 28.

FIG. 3C shows a state in which the movable scroll member 20 has revolved around the center C ₂ of the movable scroll member 20 in the clockwise direction by 00 ° about the center C ₁ as an axis. As a result, the center C ₂ of the movable scroll member 20 moves to the left side of the center C ₁ , and the volume of the closed spaces 28, 28 is reduced to reduce the closed spaces 28, 28.
The air inside is compressed from the state of (b).

(D) shows a state in which the center C ₂ of the movable scroll member 20 is revolved around the center C ₁ in the clockwise direction by 00 ° from the state of (c). As a result, the center C ₂ of the movable scroll member 20 moves to below the center C ₁ , and the volume of the closed spaces 28, 28 is reduced to reduce the closed spaces 28, 28.
Compress the air inside to a specified pressure. Then, the air compressed to a predetermined pressure is discharged from the discharge hole 15. On the other hand, air is sucked into the suction space 29 through the suction port 14 and introduced into the newly formed spaces 28a, 28a. Then, by changing from the state of (d) to the state of (a), the spaces 28a, 28a become new hermetically sealed spaces 28, 28, and the above-described steps of FIGS. 4 (a) to (d) are sequentially repeated. As a result, compressed air is discharged from the discharge port 4 shown in FIG.

A method of forming the above-mentioned anodic oxide film 23 on the compressor scroll member will be described below. Table 1 shows the conditions of the pretreatment for the first example and the first comparative example described below. That is, a treatment of removing oils and fats from the surface of the base material (aluminum material) is performed in the step before the anodized film step.

[0022]

[Table 1]

First Example and First Comparative Example: The base material in the first example and the first comparative example is AC8C-JISH5202 which is an aluminum alloy die casting material, and its main component is 2 as shown in Table 2. 0.0-4.0 wt% Cu, 8.5
It is an aluminum alloy containing ˜10.5 wt% Si and 1.0 wt% or less Fe.

[0024]

[Table 2]

The first embodiment is AC8C which has been subjected to the above-mentioned pretreatment.
A 5 μm film obtained by applying an anodic oxide film treatment to JIS H5202 using an electrolytic solution containing trisodium phosphate 0.5 wt%, sorbitol 0.9 wt% and potassium fluoride 0.3 wt% as shown in Table 3. Was generated. Liquid temperature is 10 ° C, voltage is 50V (DC), and energization time is 30mi
n.

[0026]

[Table 3]

The first comparative example is AC8C which has been subjected to the pretreatment.
-The JIS material was subjected to anodic oxide film treatment with 15 wt% sulfuric acid as shown in Table 3 to form a film of 20 μm. Liquid temperature is 3 ° C, voltage is 32V (DC), and energization time is 25
min.

In order to compare the seizure characteristics of the first example and the first comparative example, a friction wear test was conducted using the test piece of the first example and the test piece of the first comparative example. In addition, a sliding speed was set to 10 m / s by using Honda Ultra U (trade name) as a lubricant. As a result, seizure did not occur in the film formed in the first example up to a load of 0.45 Kgf / mm ² , but the film formed in the first comparative example was 0.18 Kgf / mm ^2.
Seizure occurred under the load.

FIG. 5 is a graph showing the seizure characteristics of the compressor scroll member according to the present invention in the first embodiment and the first comparative example. The vertical axis represents the load, and the horizontal axis represents the seizure time. Lubricants and sliding speeds are shown in Table 3. As a result, as described above, the film produced in the first example did not cause seizure up to a load of 0.45 Kgf / mm ² , but the film produced in the first comparative example had 0.18 Kgf / mm ^2. Seizure occurred under the load.

Table 4 shows the relationship between the Si content in the anodic oxide film and the pit generation rate.

[0031]

[Table 4]

In the second comparative example of Table 4, the ADC14-JIS material was anodized by the conventional method as in the first comparative example. Therefore, since the Si content in the anodic oxide film did not decrease, the pit generation rate was 5% or more. On the other hand, in the case of the second embodiment, the ADC14-JIS material is anodized in the same manner as in the first embodiment so that the Si content in the anodized film is 10%,
It was reduced by 3 patterns of 8% and 6%, and the pit generation rate of each pattern was examined. As a result, Si content is 10%
In the case of, the pit generation rate is 5% or more, and the Si content is 8
%, The pit generation rate was 3% to 5%, and when the Si content was 6%, the pit generation rate was 3% or less.

In the third comparative example of Table 4, the ADC12-JIS material was anodized by the conventional method as in the first comparative example. Therefore, since the Si content in the anodic oxide film did not decrease, the pit generation rate was 5% or more. On the other hand, in the case of the third embodiment, the ADC12-JIS material is subjected to the anodic oxide film treatment in the same manner as in the first embodiment so that the Si content in the anodic oxide film is 10%,
It was reduced by 3 patterns of 8% and 6%, and the pit generation rate of each pattern was examined. As a result, Si content is 10%
In the case of, the pit generation rate is 5% or more, and the Si content is 8
%, The pit generation rate was 3% to 5%, and when the Si content was 6%, the pit generation rate was 3% or less.

In the fourth comparative example of Table 4, the AC8C-JIS material was anodized by the conventional method as in the first comparative example. Therefore, since the Si content in the anodic oxide film did not decrease, the pit generation rate was 5% or more. On the other hand, in the case of the fourth embodiment, the AC8C-JIS material is anodized in the same manner as in the first embodiment so that the Si content in the anodized film is 8% and 6%.
The pit occurrence rate of each pattern was examined. As a result, the pit generation rate was 3% to 5% when the Si content was 8%, and the pit generation rate was 3% or less when the Si content was 6%.

In the fifth comparative example of Table 4, the AC4C-JIS material was anodized by the conventional method as in the first comparative example.
In this case, the pit generation rate was 3% to 5%. On the other hand, in the case of the fifth embodiment, the AC4C-JIS material is anodized in the same manner as in the first embodiment to reduce the Si content in the anodized film to 6
%, And the pit generation rate was investigated. As a result, Si
When the content was 6%, the pit generation rate was 3% or less.
As described above, it was found from Table 4 that when the Si content in the anodic oxide film was reduced, the pit generation rate of the anodic oxide film was reduced. In particular, when the Si content in the anodic oxide film is 8% or less, the pit generation rate is reduced and the anodic oxide film can be formed flat.

In the first to fifth embodiments, the case where the anodic oxide film is formed on the movable scroll member 20 has been described, but the present invention is not limited to this, and as in the sixth embodiment, electroplating is performed on the anodic oxide film. The treatment may be performed by one kind or a combination selected from dipping plating, electrolytic plating, and electrolytic coloring. Since this treatment is a pore-sealing treatment, the fine pores remaining in the anodic oxide film can be closed. In this case, since the anodic oxide films of the first to fifth embodiments have a low Si content, electrolysis of water using Si as an electrode can be neglected, so that wasteful consumption of current in electroplating or the like is suppressed. You can Further, in the first to fifth embodiments, the case where the anodic oxide film 23 is formed on the movable scroll member 20 has been described, but the same applies when the anodic oxide film is formed on the fixed scroll member 10 instead of the movable scroll member 20. Get the effect of.

[0037]

The present invention has the following effects due to the above configuration. According to a first aspect of the present invention, the scroll member is formed of an aluminum material containing Si, and the surface of the scroll member is formed of an electrolyte solution containing a compound containing an anion having a complexing property + an organic acid containing an oxygenate anion + a halide. It is designed to generate an anodic oxide film.
Since the inclusions such as Si, other added metals and intermetallic compounds are selectively dissolved and removed from the anodic oxide film together with the oxyacid anion, the baking property of the anodic oxide film is improved. Further, by covering the surface of the pair of scroll members with the anodic oxide film, the strength of the surface of the pair of scroll members increases.

Further, the compound containing an anion having a complexing property serves to flatten the anodic oxide film. That is, if the outer surface of the anodic oxide film is uneven during formation, the compound containing the anion is thickly attached to the concave portion and thinly attached to the convex portion. Apparently, the elution rate of Al ions is slow in the concave portions and high in the convex portions, and as a result, the outer surface of the anodic oxide film becomes flat.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a compressor incorporating a scroll member for a compressor according to the present invention.

FIG. 2 is an exploded view of a scroll member for a compressor according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is an operation explanatory view of a scroll member for a compressor according to the present invention.

FIG. 5 is a graph showing seizure characteristics of a scroll member for a compressor according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 10 ... Fixed scroll member (spiral scroll member), 23 ... Anodized film, 20 ... Movable scroll member (spiral scroll member).

Claims (1)

[Claims] 1. A scroll member for a compressor, which compresses a fluid by relatively rotating a pair of spiral scroll members, wherein the spiral scroll member is formed of an aluminum material containing Si, and A scroll member for a compressor, characterized in that an anodic oxide film is formed on the surface with an electrolyte solution containing a compound containing a complexing anion, an organic acid containing an oxygenate anion and a halide.