JPH06136486A - Vane - Google Patents

Abstract

PURPOSE:To obtain a vane combining seizure resistance, corrosion resistance, and wear resistance and used mainly for a compressor using HFC type fluorocarbon as refrigerant. CONSTITUTION:A vane having a composition consisting of, by weight, 2.0-4.0% C, 1.0-3.0% Si, <=0.8% Mn, >2.0-15% Co and/or Ni, <=3.0% W and/or Mo, and the balance Fe with inevitable impurities and also having a structure where crystallized or precipitated graphite grains are dispersed in a matrix is formed. Further, <=1.0% of Cr and/or V can be incorporated into the above composition, if necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane used in a compressor such as a rotary compressor and a vane pump.

[0002]

2. Description of the Related Art As shown in FIG. 1, an example of a compressor using a vane, a vane 1 is always provided with a rotor 4 by a spring 4.
Is pressed against the eccentric rotation of the rotor 2,
The refrigerant is compressed by the volume change of the space formed by the rotor and the cylinder 3. Freon gas is used as the refrigerant. Since the tip of the vane always slides in contact with the rotor and the side surface of the vane slides in contact with the cylinder, the characteristic required for the vane is that the vane itself does not wear, and at the same time, the other rotor or cylinder does not wear. is there. What is commonly used as a vane material is SKH51 equivalent high-speed molten steel containing no cobalt and nickel, and the rotor material is FC25. Further, an Fe-based sintered material described in JP-A-62-120465 has been proposed for the purpose of dispersing graphite particles in a vane material and improving self-lubricity.

[0003]

The refrigerant used in the above compressor is a chlorofluorocarbon (hereinafter referred to as CFC).
The CFCs are CFCs, but after reaching the stratosphere, these CFCs are decomposed by ultraviolet rays, and the ozone layer is destroyed by the released chlorine. For this reason, CFC
It is planned to be completely abolished by the year 2000, and development of refrigerants to replace it is underway. As an alternative refrigerant, hydrofluorocarbon (hereinafter referred to as HFC) -based CFC containing no chlorine is a promising candidate. This type of chlorofluorocarbon has little harm to the environment. However, vane pumps and rotary compressors using HFC-based CFCs have the following problems as compared with those using conventional CFC-based CFCs.

1 Lubricity of the refrigerant is poor. 2 In order to obtain the same refrigerating capacity, it is necessary to increase the compression ratio, and the load applied to the vane becomes high. 3 High hygroscopicity of the refrigerant. 4 The lubricity of the lubricating oil changed according to the refrigerant is inferior. 5 Hygroscopicity of lubricating oil is increased. 6 Lubricating oil and refrigerant decompose into carboxylic acid and hydrofluoric acid, respectively.

Due to the above reasons, when an HFC-based alternative CFC is used as a refrigerant, a corrosive wear effect is also caused to cause abnormal wear of the vane, and in a remarkable case, seizure with the rotor may occur, which may cause a compressor It has become clear that it is not possible to obtain a practical life as. This is because the seizure occurred due to microscopic adhesion involving the corrosive wear of the base. Although the rotor material is FC25 in which flake graphite with excellent seizure resistance is dispersed, when using an HFC-based alternative CFC as a refrigerant, the effect of preventing seizure by graphite in the combination of conventional vane material and FC25 There was a problem that could not be fully exerted. On the other hand, if the vanes themselves are made of graphite, the wear characteristics are dramatically improved, but the strength of the graphite is insufficient and there is a problem in reliability. The purpose of the present invention is mainly H
It is an object of the present invention to provide a novel vane material used in a compressor using FC-based CFC as a refrigerant.

[0006]

The first aspect of the present invention is to provide C2.0-4.0% by weight and Si1.0-3.0.
%, Mn 0.8% or less, Co and Ni 1 type or 2 types exceeding 2.0% and 15% or less, W and Mo 1 type or 2 types 3.0% or less, balance Fe and unavoidable impurities. The composition is a vane characterized in that graphite particles crystallized or precipitated in a matrix are dispersed in the matrix.
Of the present invention, C2.0-4.0% by weight%, Si1.0-
3.0%, Mn 0.8% or less, Co and Ni 1 type or 2 types over 2.0% and 15% or less, W and Mo 1 type or 2 types 3.0% or less, balance Fe and A vane characterized by comprising an inevitable composition of impurities, the structure of which is dispersed graphite particles crystallized or precipitated in a matrix, and further containing 0.1 to 5.0% by weight of graphite particles. Is.

A third aspect of the present invention is C2.0-3.5% by weight.
%, Si 1.5 to 2.5%, Mn 0.8% or less, Co or Ni 1 type or 2 types 7.0 to 12%, W and Mo 1%
3.0% or less of two kinds or two kinds, and the composition of the balance Fe and unavoidable impurities, and the structure thereof has crystallized or precipitated graphite particles dispersed in a matrix. The present invention is a vane characterized by being added by 2.0% to 2.0%, and a fourth invention is the composition described in any one of the first to third inventions, wherein one or two kinds of Cr and V are added. 0
% Or less, the fifth invention is a base having the composition according to any one of the first to fourth inventions,
Co and Ni are solid-dissolved, the area ratio of the graphite particles uniformly dispersed in the matrix is 2 to 20%, and the matrix hardness is H.
RC55-67, first to fourth characterized in that
The vane according to any one of the inventions.

[0008]

The function of each element and the reason for limiting the numerical values in the present invention will be described below. As described later, C is an important element added mainly for finely crystallizing graphite in the matrix by the rapid solidification method. The rest partly forms a solid solution in the matrix to increase the hardness and forms carbides and cementite. When C is less than 2.0%, the amount of crystallized graphite is at the same level as that of the current graphite steel, and there is no improvement in wear resistance and sliding characteristics. On the contrary, when it exceeds 4.0%, the mechanical properties are Since it deteriorates and cannot be practically used as a mechanical structural part, the range of C is limited to 2.0 to 4.0%. The range of C in which desirable characteristics are obtained is 2.0 to 3.5%.

Si is a ferrite stabilizing element that prevents crystallization of cementite and is an element that promotes crystallization of graphite. 1.0
%, The crystallization effect of graphite is insufficient, and conversely 3.0
%, The base becomes brittle, so the range of Si is 1.
It is limited to 0 to 3.0%. Desirable Si range is 1.5
~ 2.5%. Mn has an effect of improving the steel quality as a deoxidizing element and an effect of precipitating it as MnS to suppress the harmfulness of S. The addition of more than 0.8% has no effect corresponding to the added amount and embrittles the material. Therefore, the range of Mn is set to 0.8% or less.

Co and Ni are elements that have important effects in the present invention. That is, when a Co- and Ni-free Fe-based material in which only graphite particles are dispersed is used as a vane material for a compressor using an HFC-based alternative CFC as a refrigerant, graphite is excellent in self-lubricating property. Although not abraded, the base itself is inferior in wear resistance and microscopically seizes with the mating material, making it unsuitable as a vane material. In addition, Co and Ni
Since no base metal is added, the base is inferior in corrosion resistance to the non-additive material. In order to solve this, in the present invention, it was found that the base is strengthened by adding Co and Ni alone or in combination, and seizure resistance and corrosion resistance are provided. In particular, with regard to corrosion resistance, it has an action of suppressing corrosion caused by an acid generated by the decomposition of the refrigerant and the lubricating oil, that is, hydrofluoric acid or carboxylic acid.

One or two kinds of Co and Ni are added to 2.0%.
By dissolving in the matrix in the range of more than 15% and less than 15%, abnormal wear accompanied by corrosion can be reduced. If the total amount of Co + Ni exceeds 15%, the toughness decreases, so the upper limit was made 15%. Further, if the content is 2.0% or less, the above effect cannot be obtained. Therefore, the range is set to more than 2.0% and 15% or less. Note that Co has the effect of increasing the hardness of the matrix, suppressing seizure with the rotor that is the mating material, and suppressing vane wear. Further, Ni suppresses coarsening of crystallized graphite due to Si and promotes graphitization of cementite. Co also has an effect of promoting graphitization of cementite. The desirable range of Co and Ni is 7.0 to 12%. Both Mo and W are strong carbide-forming elements, and while carbide is precipitated, some of them have the effect of forming a solid solution in the matrix to increase the matrix hardness. Further, Mo solid-dissolved in the matrix also has an effect of suppressing corrosion due to carboxylic acid. However, Mo
When the total amount of W and W exceeds 3.0%, the amount of precipitated as carbide becomes larger than that of solid solution in the matrix, which is not desirable for the vane of the present invention. Therefore, one or two kinds of Mo and W are set to 3.0% or less.

Cr and V are both carbide-forming elements, and some of them have the effect of increasing the hardness of the matrix by forming a solid solution in the matrix. Further, Cr solid-dissolved in the matrix has an effect of suppressing corrosion due to carboxylic acid. However, if the total amount of Cr and V exceeds 1.0%, the amount of precipitation as a carbide becomes larger than that of solid solution in the matrix, so that sufficient matrix hardness cannot be obtained or the corrosion resistance is deteriorated. Not desirable for vanes. Therefore, the upper limit of one or two of Cr and V added as necessary is set to 1.0%.

As described above, the graphite particles have excellent self-lubricating properties, do not wear the mating material, and have a large amount of graphite, the friction characteristics are improved. A large amount of C is required to uniformly disperse many graphite particles only by the method of crystallization or precipitation, but this results in deterioration of formability and sinterability. Therefore, it is effective to add graphite powder prior to sintering in order to further improve the friction characteristics. If the amount of graphite powder added is less than 0.1% by weight, this effect is not sufficient because it may not obtain sufficient matrix hardness or deteriorates corrosion resistance. If it exceeds 5%, a large amount of stable quality vanes will be produced. Since it cannot be produced, it was set to 0.1 to 5%.
A desirable amount of graphite powder added is 0.1 to 2.0%.

Further, it is desirable that the graphite particles uniformly dispersed in the matrix have a spherical shape in order to improve wear resistance and sliding characteristics. If the area ratio of graphite is less than 2%, the effect of preventing seizure is not sufficient, and if it exceeds 20%, stable quality vanes cannot be mass-produced.
-20%. In the sintered material of the present invention, it is desirable to subject the base hardness to HRC55 to 67 by performing a predetermined heat treatment in order to improve the wear resistance of the vane itself. HRC55
If it is less than 1, the matrix hardness is insufficient and the wear resistance is insufficient. Further, if it exceeds HRC67, mechanical properties such as toughness are deteriorated and the wear of the mating material is increased.
And

[0015]

EXAMPLES Examples of the present invention will be shown below. (Example 1) Alloy powders having the compositions shown in Table 1 were produced by a water atomizing method. However, the symbols X and Y are conventional steels, the symbol X is a molten high speed tool steel made of SKH51, and the symbol Y is graphite steel. Of these alloy powders, powders having a particle size of 150 μm or less were used, and 0.7% of zinc stearate was added and mixed after the reduction treatment. After press-molding at a molding pressure of 6 t / cm2 and degreasing, 1210-1240 ° C under vacuum
And sintered for 1 hour. In the vane of the present invention, the symbols A to Q were under the above conditions, and the symbols R to T were the same as above, except that graphite particles were added to the alloy powder.

[0016]

[Table 1]

In Table 2, quenching of the vane material shown in Table 1-
The tempering hardness, the area ratio of graphite contained in this state, the seizure surface pressure by the abrasion test, and the corrosion weight loss by the corrosion test are shown. The abrasion test was carried out by the pin / disk method in the following manner. The vane material is a round rod-shaped pin, the FC25 corresponding to the rotor material is a disk, and it is immersed in an ester-based lubricating oil compatible with HFC134a, which is a representative of HFC-based CFCs, and slid at a speed of 2 m / s to obtain an initial surface pressure. Was set to 10 kgf / cm ² and a pressure of 5 kgf / cm ^{2 was} applied every 3 minutes to determine the seizure surface pressure. The corrosion weight loss was calculated from the weight change after each corrosion solution was kept at 60 ° C. for 5 hours.

[0018]

[Table 2]

(Embodiment 2) The vanes were actually formed using the materials of the symbols B and G of the present invention shown in Table 1 and the conventional molten high speed tool steel SKH51 (symbol X). It was made, and the rotor was made of FC25 (HRC50), and HF
A life evaluation test was carried out by incorporating it into an actual rotary compressor using C134a as a refrigerant. In the evaluation of the actual machine test, the wear and damage of the vane was estimated by the pressure of the pressure gauge installed in the rotary compressor. As a result of the actual machine test, the pressure of the test machine using the conventional material SKH51 for the vane suddenly changed 125 hours after the start of the operation, so the operation was stopped and the condition of the vane was observed. As a result, the SKH51 vane was partially seized on the surface sliding on the rotor. On the other hand, scratches due to seizure were also observed on the rotor sliding surface. On the other hand, in the rotary compressor using the vanes made of the symbols B and G of the present invention, the pressure change was not observed even after 1000 hours of operation, and the test was stopped.

[0020]

EFFECTS OF THE INVENTION According to the present invention, in a compressor using a CFC alternative to HFC CFC as a refrigerant, seizure resistance and corrosion resistance, which were insufficient in the conventional vane material SKH51 class, are remarkably improved. In addition, the vane of the present invention,
The solid solution of Co and Ni in the matrix and the uniform dispersion of graphite in the matrix not only have a great effect of suppressing wear and seizure of the rotor or cylinder, which is the mating material, but also Co and Ni are used for the HFC-based CFC compressor. It has a high corrosion resistance against the acid generated by the decomposition of the lubricating oil and the refrigerant. Therefore, the vane of the present invention having excellent seizure resistance, corrosion resistance, and wear resistance can cope with a refrigerant having poor lubricity, so that a compressor that complies with CFC regulations can be put to practical use.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a rotary compressor.

[Explanation of symbols]

 1 vane 2 rotor 3 cylinder 4 spring

Claims (5)

[Claims] 1. C2.0-4.0% by weight%, Si1.
0-3.0%, Mn 0.8% or less, Co and Ni 1 or 2 more than 2.0% and 15% or less, W and Mo 1 or 2 3.0% or less, balance A vane comprising a composition of Fe and unavoidable impurities, the structure of which is a matrix in which crystallized or precipitated graphite particles are dispersed. 2. C2.0-4.0% by weight%, Si1.
0-3.0%, Mn 0.8% or less, Co and Ni 1 or 2 more than 2.0% and 15% or less, W and Mo 1 or 2 3.0% or less, balance The composition is composed of Fe and unavoidable impurities, and the structure is such that crystallized or precipitated graphite particles are dispersed in the matrix, and the graphite particles are added in an amount of 0.1 to 5.0% by weight. Vane to do. 3. C2.0-3.5% by weight, Si1.
5 to 2.5%, Mn 0.8% or less, Co and Ni 1 type or 2 types 7.0 to 12%, W and Mo 1 type or 2 types 3.0% or less, balance Fe and unavoidable The composition of the impurities is such that the crystallized or precipitated graphite particles are dispersed in the matrix, and the graphite particles are contained in a weight ratio of 0.1 to 0.1.
A vane characterized by being added at 2.0%. 4. A vane containing 1.0% or less of one or two of Cr and V in the composition according to any one of claims 1 to 3. 5. Co and Ni are solid-dissolved in the matrix having the composition according to claim 1, and the area ratio of the graphite particles uniformly dispersed in the matrix is 2 to 20%. Is HRC55-67. The vane of claims 1-4.