JPH076068B2 - Vane for rotary compressor - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to a vane for a rotary compressor, and more particularly to a vane for a rotary compressor made of a sintered member having high wear resistance.

(Prior Art) Conventional rotary compressors have been used in air conditioners and showcases, and are composed of, for example, a cylinder, a rotor that eccentrically rotates inside the cylinder, and a vane that is coupled to the cylinder and slides with the rotor. In this rotary compressor, the vane is constantly pressed against and contacts the rotating rotor, and reciprocates in accordance with the rotation of the rotor, thereby partitioning the inside of the cylinder by pressure. For this reason, the vane is of course airtight,
High wear resistance is required because the parts that are in sliding contact with the rotor and the parts that are in contact with the cylinder are significantly worn.

Conventionally, most of the vanes of this rotary compressor are manufactured by using a melting material having high wear resistance such as high speed steel or eutectic graphite cast iron. Recently, a sintered body made of an iron-based powder has been developed by subjecting it to steam treatment to improve wear resistance and airtightness.

(Problems to be solved by the invention) In recent air conditioners, however, there are some that require severe operating conditions such as use in a tropical region such as the Middle East or installation of an inverter. The rotary compressor used in the machine is required to have more severe operating conditions than before, that is, high speed operation and variable speed operation. Along with this, the vanes provided in the rotary compressor are also required to have higher wear resistance than in normal cases because they operate at high speed.

In view of the above-mentioned points, it is an object of the present invention to provide a vane for a rotary compressor, which is made of a sintered member having high wear resistance capable of withstanding severe usage conditions.

[Structure of the Invention] (Means and Actions for Solving the Problems) The vane for a rotary compressor of the present invention is based on trivalent chromium oxide (Cr ₂ O ₃ ) produced by a thermochemical reaction from a hexavalent chromium compound. It is characterized by comprising a sintered member having on the surface of.

The hexavalent chromium compound is preferably impregnated or chemically bonded to the substrate. In this case, the chromium compound is liquid, and chromate, dichromate, etc. can be applied. In addition, you may contain zinc oxide, silicon oxide, aluminum oxide etc. as needed.

Note that the substrate can be sufficiently impregnated with the chromium compound reaction liquid as long as it has 60% or more, preferably 80% or more of communication holes (open pores) of the sintered pores of the sintered body. In order to obtain such communication holes, in the process of obtaining a sintered body from a molded body, the molding pressure is 5 to 10 tons / cm ² , preferably 4 to 8 tons / cm ² , and the sintering temperature is 1000 to 1500 ° C. , Preferably 1100 ~ 1300 ℃, sintering atmosphere is hydrogen, vacuum, non-oxidizing,
A hydrogen atmosphere is preferably used. The base material is preferably made of a material having excellent wear resistance and corrosion resistance, such as Cr
Or stainless steel containing Ni or W, M
A sintered body containing o, Cu, C, etc. is preferable.

In order to obtain a vane for a rotary compressor of the present invention, for example, a sintered member having a predetermined shape is immersed in an impregnating solution containing a hexavalent chromium compound as a main component, and then subjected to heat treatment to obtain a thermochemical property. Trivalent chromium oxide (Cr
₂ O ₃ ). Then, by repeating this cycle a plurality of times, a vane for a rotary compressor made of a sintered member having a desired surface state is obtained.

The vane for a rotary compressor made of the sintered member thus obtained has a Vickers hardness Hv of 500 or more, and since the adhesion between the surface layer and the substrate is good, it has excellent wear resistance and corrosion resistance.

(Example) -Example 1 40% of iron alloy powder containing 10 to 30% of chromium and 1.5 of graphite powder
%, The balance iron-nickel-copper-molybdenum powder is mixed, chromium 4-12%, nickel 0.1-2%, copper
A raw material powder consisting of 0.1 to 2%, molybdenum 0.1 to 1%, carbon 0.8 to 1.5% and the balance iron was obtained. This raw material powder has a molding pressure of 4
By pressing at -8 ton / cm ² , a 16 × 10 × 5 (cm) molded body was produced. This compact was sintered in a hydrogen atmosphere at a temperature of 1100 to 1250 ° C. and then rapidly cooled to obtain a quenched structure. The ratio of communicating holes at this time is 80 to 90
%Met.

The sintered body thus obtained was subjected to the following three treatments.

The sintered body is dipped in a solution containing chromic acid as the main component with a specific gravity of 1.6 to 1.7, and the thermochemical reaction is repeated multiple times (3 to 10 times) while gradually increasing the temperature between 310 and 700 ° C. went. By this treatment, a dark green chromium oxide (Cr ₂ O ₃ ) layer was obtained on the surface of the sintered body and around the sintered holes (communication holes).

Temperature of sintered body is 500-650 ℃, pressure is 1.1-3 atmospheres, time
Conventional steam treatment was performed under the condition of 0.5 to 3 hours.

The conventional tempering treatment was performed on the sintered body under the conditions of a temperature of 500 to 650 ° C. and a time of 0.5 to 3 hours.

Abrasion resistance of the treated material subjected to these treatments was evaluated by an Amsler type abrasion test. The conditions at this time were a load of 25 kg, one drop of oil applied before the test, a wear rate of 2 m / sec, and a test time of 2 hours. As a result, 0.6m after processing
The wear of 0.7 mm was obtained with the treatment of m, and 1.1 mm with the treatment of m.

Example 2 Graphite powder 0.3 to 0.8%, the balance iron-nickel-copper-molybdenum powder mixed powder, nickel 0.1-10%, copper
A raw material powder consisting of 0.1 to 10%, molybdenum 0.1 to 1%, carbon 0.2 to 0.8%, and the balance iron was obtained. This raw material powder has a molding pressure of 4
By pressing at -8 ton / cm ² , a 16 × 10 × 5 (cm) molded body was produced. This compact was sintered in a hydrogen atmosphere at a temperature of 1100-1250 ° C. The ratio of the communicating holes at this time was 75 to 85% of the whole sintered holes.

The above three treatments were applied to the thus obtained sintered body.

The treated materials subjected to these treatments were evaluated for wear resistance by the Amrasler wear test under the same conditions as in Example 1. As a result, it was found that the wear of 1.2 mm was carried out by the treatment of 1, the wear of 1.4 mm was carried out by the treatment of 2.1 mm, and the wear of 2.1 mm was carried out by the treatment carried out.

Example 3 Chromium 4-12%, molybdenum 4-12%, tungsten 4
A raw material powder consisting of ~ 12%, cobalt 0.1-4%, vanadium 0.1-4%, carbon 0.8-1.5%, and the balance iron was prepared. This raw material powder is pressed at a molding pressure of 4 to 8 ton / cm ² to produce 16 × 10
A molded product of × 5 (cm) was manufactured. This compact was sintered in a hydrogen atmosphere at a temperature of 1100-1250 ° C. The ratio of the communicating holes at this time was 80 to 90% of the whole sintered holes. The above three treatments were applied to the thus obtained sintered body.

The treated material subjected to these treatments was evaluated for abrasion resistance by the Amsler abrasion test under the same conditions as in Example 1. As a result, the wear was 0.5 mm for the treatment, 0.6 mm for the treatment, and 0.8 mm for the treatment.

As is clear from these examples, when the same sintered body is treated, the present invention has excellent wear resistance as compared with the conventional ones which are subjected to tempering treatment or steam treatment.

[Effects of the Invention] As described above, the vane for a rotary compressor of the present invention has a hardness higher than that of the conventional vane and has excellent wear resistance, and can withstand severe usage conditions. Is.

Claims (2)

[Claims] 1. A vane for a rotary compressor, comprising a sintered member having a trivalent chromium oxide (Cr ₂ O ₃ ) produced by a thermochemical reaction from a hexavalent chromium compound on the surface of a substrate. 2. The vane for a rotary compressor according to claim 1, wherein the base is a sintered body having 60% or more of communicating holes among the sintering holes.