JPH10115296A - Refrigerant compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a friction coefficient and improve a wear resistance by using a rotary shaft applied a plasma sulfonitriding process on the surface. SOLUTION: A refrigerant poured from a suction pipe 19 in a cylinder 7 is discharged in a discharge muffler 17 and discharged from the discharge pipe 20 to the outside of an air-tight vessel 1 through an electric element 2. An oil 18 poured in the bottom of the air-tight vessel 1 is sucked up through the hollow hole 21 of the rotary shaft 8 by a vacuum phenomenon by the high speed rotation of the rotary shaft 8 and supplied to the slide surface of the slide member of the roller 10 and vane 12 of the rotation compression element 3 and the slide surface between the rotary shaft 8 and upper/lower bearings 13, 14 and a lubrication is carried out. The refrigerant compressed in the cylinder 7 prevents the leak to a low pressure side. The rotary shaft 8 is made by high elastic FCD and the plasma sulfonitriding process is applied on its surface and a front layer part contained sulphur is formed by the chemical reaction of iron and sulphur on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant compressor, and more particularly, to a refrigerant compressor used in a refrigeration system using an HFC-based refrigerant or the like which does not have a risk of destructing an ozone layer. The present invention relates to a refrigerant compressor having improved wear resistance of a sliding surface of a rotating shaft.

[0002]

2. Description of the Related Art Conventionally, dichlorodifluoromethane (R-12) or R-502 composed of azeotropic refrigerant R-22 and monochloropentafluoroethane (R-115a) has been used as a refrigerant for a refrigerator. , These refrigerants
A refrigeration cycle that is suitable for ordinary refrigeration equipment and uses refrigeration oil such as mineral oil or alkylbenzene-based oil that is compatible with the refrigerant has reached high quality levels such as reliability and durability.

[0003] However, the above-mentioned refrigerant has high ozone depletion, and when released into the atmosphere and reaches the ozone layer above the earth, the ozone layer is destroyed. This destruction of the ozone layer is caused by chlorine groups (Cl) in the refrigerant. Therefore, a refrigerant having a low chlorine group content, such as chlorodifluoromethane (HCFC-22, R-22), a refrigerant containing no chlorine group, such as difluoromethane (HFC-32,
R-32), pentafluoroethane (HFC-125,
R-125) and 1,1,1,2-tetrafluoroethane (HFC-134a, R-134a) are considered as these alternative refrigerants (hereinafter referred to as HFC-based refrigerants). Refrigeration oils used for HFC-based refrigerants include mineral oils and alkylbenzene-based oils that are not compatible with HFC-based refrigerants, ester-based refrigeration oils that are compatible with HFC-based refrigerants, and ether-based refrigeration oils. And mixed oils.

Conventionally, the surface of the rotating shaft of a compressor such as a rotary compressor or a reciprocating compressor has been subjected to salt bath nitrocarburizing treatment, ion nitriding treatment, and salt bath in order to improve the wear resistance of the sliding surface. Surface treatments such as nitrosulphurizing and electrolytic sulphonitriding were performed, but when the refrigerant was replaced by HFC-based refrigerants and the refrigerating machine oil was transferred to ester-based or ether-based refrigerating machine oils, these conventional treatments Compound layer [Nitride (ε-F
e ₃ N) as a main component], the friction coefficient is high, the wear resistance is insufficient, and stable operation cannot be performed for a long period of time. Therefore, a rotary compressor with an improved rotary shaft, a reciprocating type There is a strong demand for compressors such as compressors.

[0005] Further, when the refrigerant is replaced with an HFC-based refrigerant and the refrigerating machine oil is changed to an ester-based refrigerating machine oil or an ether-based refrigerating machine oil, it is necessary to use a highly elastic FCD (ductile cast iron) for the material of the rotating shaft. High elasticity material, especially F
When a CD is used, the center hole of the rotating shaft (the hole for circulating the refrigerating machine oil from the oil reservoir at the lower part of the refrigerant compressor to the upper part of the refrigerant compressor) has been opened by conventional machining. It becomes difficult. There is a strong need for a refrigerant compressor having a high elasticity rotating shaft whose center hole is easily made economically.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a refrigerating machine oil that uses an ester-based refrigerating machine oil, an ether-based refrigerating machine oil, or an HFC-based refrigerant. To provide a refrigerant compressor having a rotating shaft having a low coefficient of friction and high wear resistance, and to provide a refrigerant compressor having a high-elastic rotating shaft having a center hole easily and economically formed. That is.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems, and as a result, by subjecting the surface of the rotating shaft to plasma sulphiditriding, the friction coefficient is low and the wear resistance is low. The present invention has been found to be improved and that the above problem can be solved by creating a center hole using a vanishing model or a shell core at the stage of casting the rotating shaft, thereby completing the present invention.

That is, the invention of claim 1 of the present invention comprises a compression element driven by a rotary shaft,
A refrigerant compressor in which a refrigerant mainly composed of a C-based refrigerant or an HFC-based refrigerant is compressed and discharged by the compression element, and uses a rotating shaft having a surface subjected to a plasma nitrosulphurizing process as the rotating shaft. It is a refrigerant compressor characterized by the above-mentioned.

According to a second aspect of the present invention, in the refrigerant compressor according to the first aspect, an FCD rotary shaft is used as the rotary shaft.

According to a third aspect of the present invention, there is provided the refrigerant compressor according to the second aspect, wherein a center hole is formed using a vanishing model or shell core in the casting step of the rotating shaft.
It is characterized by using a rotating shaft made of CD.

According to a fourth aspect of the present invention, in the refrigerant compressor according to any one of the first to third aspects, the refrigerating machine oil is an ester lubricating oil, an ether lubricating oil, or a mixture thereof. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. FIG. 1 shows a refrigerant compressor a of the present invention which compresses an evaporated HFC-based refrigerant and discharges the refrigerant to a condenser, a condenser b which condenses and liquefies the refrigerant, a capillary tube c which reduces the pressure of the refrigerant, and a liquefied refrigerant. 3 shows a refrigeration cycle of a refrigeration apparatus in which evaporators d and the like for evaporating are sequentially connected by a refrigerant pipe.

FIG. 2 is a longitudinal sectional view of an example of the refrigerant compressor of the present invention. FIG. 3 is a cross-sectional view of the refrigerant compressor of the present invention shown in FIG. 2 and 3, reference numeral 1 denotes a closed container, in which an electric element 2 is accommodated on the upper side, and a rotary compression element 3 driven by the electric element is accommodated on the lower side. The electric element 2 includes a stator 5 having a winding 4 insulated with an organic material and a rotor 6 provided inside the stator. The rotary compression element 3 includes a cylinder 7, a roller 10 that rotates along an inner wall of the cylinder 7 by an eccentric portion 9 of a rotation shaft 8, and a pressure contact with a peripheral surface of the roller to move the inside of the cylinder 7 into a suction side and a discharge side. It is composed of a vane 12 pressed by a spring 11 so as to be partitioned, and an upper bearing 13 and a lower bearing 14 that seal the opening of the cylinder 7 and support the rotating shaft 8.

The upper bearing 13 is provided with a discharge hole 15 communicating with the discharge side of the cylinder 7. A discharge valve 16 for opening and closing the discharge hole 15 and a discharge muffler 17 are attached to the upper bearing 13 so as to cover the discharge valve.

An HFC-based refrigerant, for example, a refrigerant mixture of three kinds of R134a, R32 and R125 or a refrigerant mixture of two kinds of R32 and R125 is sealed in the bottom of the closed vessel 1.

An oil 18 such as an ester-based refrigerating machine oil or an ether-based refrigerating machine oil as a refrigerating machine oil lubricates a sliding surface between the roller 10 and the vane 12 which are sliding members of the rotary compression element 3.

As described above, the refrigerant flowing into the cylinder 7 of the rotary compression element 3 and compressed by the cooperation of the roller 10 and the vane 12 is, for example, R407C [R134a and R32C].
Refrigerant mixture of R32 and R125] or R410A [R32 and R1
25 mixed refrigerant].

Reference numeral 19 denotes a suction pipe which is attached to the closed vessel 1 and guides the refrigerant to the suction side of the cylinder 7. Reference numeral 20 denotes a suction pipe which is attached to the upper wall of the closed vessel 1 and is compressed by the rotary compression element 3 via the electric element 2. This is a discharge pipe for discharging the refrigerant to the outside of the closed container 1.

The refrigerant flowing from the suction pipe 19 to the suction side in the cylinder 7 is compressed by the cooperation of the roller 10 and the vane 12, is discharged through the discharge hole 15, opens the discharge valve 16, and is discharged into the discharge muffler 17. Is done. The refrigerant in the discharge muffler is discharged from the discharge pipe 20 to the outside of the closed container 1 via the electric element 2. Then, the oil 1 put in the bottom of the closed container 1
8 is sucked up through the hollow hole 21 of the rotating shaft 8 by a vacuum phenomenon caused by a vortex generated at the upper open end by the high speed rotation of the rotating shaft 8, and slides on sliding members such as the roller 10 and the vane 12 of the rotating compression element 3. Moving surface, rotating shaft 8 and upper bearing 1
3. The lubrication is performed by being supplied to a sliding surface with the lower bearing 14. Further, the refrigerant compressed in the cylinder 7 is prevented from leaking to the low pressure side.

The rotating shaft 8 is made of a high elasticity FCD.
Since the surface has been subjected to the plasma sulphonitriding treatment, the surface has a low coefficient of friction and a high abrasion resistance. Therefore, even if the refrigerant is replaced with an HFC-based refrigerant and the refrigerating machine oil is shifted to an ester-based refrigerating machine oil or an ether-based refrigerating machine oil, the coating is peeled off at the sliding surface between the rotating shaft 8 and the upper bearing 13 and the lower bearing 14. There is no. The surface with low friction coefficient and high wear resistance is obtained by plasma sulphiditriding.
Iron and sulfur on the surface of the rotating shaft 8 undergo a chemical reaction (generate iron sulfide) due to the plasma sulphidizing and nitriding treatment, so that a sulfur-containing surface layer is formed, thereby lowering the friction coefficient. It is considered that a layer having high wear resistance can be obtained because a layer (FeN, Fe ₃ N _4, etc. is formed) is obtained, but the present invention is not limited to this concept.

The conditions for the plasma sulphidizing and nitriding used in the present invention are not particularly limited. As a specific example of the processing conditions, for example, the rotating shaft 8 is heated to 540 to 570 ° C. in a furnace for 1 to 2 hours, and is heated in an atmosphere of N ₂ / H ₂ = 1: 1 for about 2 hours.
And then N ₂ / H ₂ S at 540-570 ° C.
After the treatment in a mixed gas atmosphere for about 3 hours, a method of cooling in a furnace (3 Torr) for about 2 hours can be given. In addition, since the rotary shaft 8 has the center hole 21 formed by using the disappearing model or the shell core at the casting stage, there is no need to drill the hole by post-machining.

The type of the refrigerant compressor of the present invention may be a closed type compressor as described above, or may be an open type compressor, and is not particularly limited. Specifically, for example, a rotary compressor, a reciprocating compressor, a vibration compressor, a multi-vane rotary compressor, a scroll compressor and the like can be exemplified.

[0023]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (Embodiment 1) A rotating shaft 8 having a center hole 21 formed by using a vanishing model shell core in a casting stage is put into a furnace, and the core is put into a furnace.
The rotary shaft 8 is heated to 570 ° C. over time, and N ₂ / H ₂
= 1: 1 gas was 2 hours in an atmosphere supplying, N ₂ / H ₂ = 1 at subsequently 570 ° C.: 1 and N ₂ / H ₂ S = 9
After treating for 3 hours in an atmosphere supplying a 9: 1 mixed gas, the furnace was cooled (3 torr) for 2 hours to perform plasma sulphiditriding. A durability test was performed under the following test conditions using a bench stand test apparatus in which a rotary compressor, a condenser, an expansion valve, and an evaporator equipped with the rotary shaft 8 having been subjected to the plasma sulphiditriding process were connected by piping. The degree of wear of the sliding part of the rotary shaft of the rotary compressor was measured.

Pressure conditions: high pressure 27-28 kg / cm ² ·
G, Low pressure: 4.6 kg / cm ² · G Operating frequency: 100 HZ, Operating time: 1000 hr, Refrigerant: DuPont R407C [52:23:25 mixed refrigerant of R134a, R32 and R125] Upper case temperature: 95 １００100 ° C. Each material of the sliding portion is as follows. Vane: High Speed Tool Steel
e) Roller: Cast iron composition (wt%): T.I. C (total carbon): 3.0 to 3.7 Si: 1.5 to 2.5, Mn: 0.5 to 1.0, P: 0.2 to 0.3, S: 0.15 or less Ni : 0.15 to 0.4, Cr: 0.5 to 1.2 MO: 0.15 to 0.4 The balance is iron

Lubricating oil composition (oil): A polyol ester-based oil (Freol α68S, manufactured by Japan Energy Co., Ltd.) is used as a base oil, and 0.1 to 2.0% by weight of tricresyl phosphate based on the base oil. (TCP) and 0.01
One containing an additive (EP) with epoxy of 10 to 10% by weight. Further, 0.05 to 0.5% by weight of 2,6-di-t-butyl-paracresol is added to the base oil.

As a result of the test, the degree of wear of the rotating shaft 8 was 1. The numbers represent the degree of abrasion on a five-point scale.
Is bad, 3 is an acceptable range, and 1 is good.

(Comparative Example 1) A test was performed in the same manner as in Example 1 except that the rotating shaft 8 subjected to ion nitriding was used instead of the plasma sulphating and nitriding. As a result of the test, the degree of wear of the rotating shaft 8 was 4.

[0028]

According to the present invention, as described above, even if an ester-based refrigerant oil or an ether-based refrigerant oil is used as the refrigerating machine oil or an HFC-based refrigerant is used, the surface of the rotating shaft slides. Coefficient of friction in the part is low,
The refrigerant compressor having high wear resistance and having this rotating shaft can be operated stably for a long period of time. In addition, the center hole of the rotating shaft can be easily created economically.

[Brief description of the drawings]

FIG. 1 is a refrigeration circuit diagram of a refrigeration apparatus.

FIG. 2 is a longitudinal sectional view of an example of the refrigerant compressor of the present invention.

FIG. 3 is a cross-sectional view of the refrigerant compressor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Electric element 3 Rotary compression element 4 Winding 5 Stator 6 Rotor 7 Cylinder 8 Rotation axis 9 Eccentric part 10 Roller 11 Spring 12 Vane 13 Upper bearing 14 Lower bearing 15 Discharge hole 16 Discharge valve 17 Discharge muffler 18 Oil 19 suction pipe 20 discharge pipe 21 hollow hole

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhisa Ishikawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Takeo Komatsubara 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Masahiko Kamada 281-2-2, Aihara-cho, Machida-shi, Tokyo (72) Inventor Sachicho Suga 1-2-15, Miyashita-honmachi, Sagamihara-shi, Kanagawa (72) Inventor Suma Hiroyuki 362-1-405 Oi, Tsukui-cho, Tsukui-gun, Kanagawa Prefecture (72) Inventor Kyoji Ito 900-56-606

Claims (4)

[Claims] 1. A refrigerant compressor comprising a compression element driven by a rotating shaft, wherein a compressed HFC-based refrigerant or a refrigerant mainly composed of an HFC-based refrigerant is compressed by the compression element and discharged. A refrigerant compressor characterized by using a rotating shaft having a surface subjected to a plasma sulphonitriding process as the rotating shaft. 2. The refrigerant compressor according to claim 1, wherein an FCD rotary shaft is used as the rotary shaft. 3. The refrigerant compressor according to claim 2, wherein a hollow FCD rotary shaft having a central hole formed by using a vanishing model or a shell core is used in the step of casting the rotary shaft. 4. The refrigerant compressor according to claim 1, wherein the refrigerating machine oil is an ester lubricating oil, an ether lubricating oil, or a mixture thereof.