JP2002031055A - Hermetic compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the abrasion of a shaft caused by using a HFCs refrigerant or a natural refrigerant which does not contain chlorine and has a low abrasion resistance or is operated under a high load, and to improve reliability. Provide a high rate compressor. SOLUTION: It is made of a material containing at least one component of Al, Cr, V, Mo, Ti, and Si at 0.2% or more and having a modulus of longitudinal elasticity of 190 GPa or more. By using a shaft having a surface hardness of Hv 1000 or more manufactured by a nitriding process for nitriding, the wear resistance of the shaft is improved, and the reliability of the compressor is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic compressor for refrigeration and air conditioning equipment.

[0002]

2. Description of the Related Art As a closed type electric compressor for refrigeration and air conditioning, there are a reciprocating type, a rolling piston type and a scroll type of a compression mechanism, all of which are used in home and commercial refrigeration and air conditioning fields. It is used. Each type of compressor includes a shaft for driving a compression mechanism, and some other sliding parts. Here, a conventional technology will be described taking a scroll compressor for an air conditioner as an example.

FIG. 5 is a longitudinal sectional view of a conventional scroll compressor. A compression mechanism unit 2 including a fixed scroll 2 a and a movable scroll 3, a shaft 5 for orbiting the movable scroll 3 with respect to the fixed scroll 2 a via an Oldham coupling 4, and a fixed scroll inside the sealed container 1. A bearing member 6 for fixing the shaft 2a and rotatably supporting the shaft 5 is provided.

A rotor 7a of an electric motor 7 is attached to the shaft 5, and is disposed below the bearing member 6 together with a stator 7b shrink-fitted and fixed in the closed casing 1.
The journal bearing 6a is formed by press-fitting an annular main-shaft-side bush member 8a into the bearing member 6, and supports a radial force acting on the shaft 5. The eccentric bearing 3a of the orbiting scroll 3 is also formed by press-fitting the annular eccentric shaft side bushing material 8b.
Radially acting on the eccentric shaft 5a.

An oil reservoir 10 for storing a lubricating oil 9 is provided at a lower bottom portion of the closed container 1. The lubricating oil 9 in the oil reservoir 10 is sucked from the lower end of the through hole 13 of the shaft 5 as the shaft 5 rotates. , Journal bearing 6a, eccentric bearing 3
a, and a supply pipe for the refrigerant gas and a discharge pipe 16 are provided outside the closed casing 1 for supplying to the sliding surfaces.

Next, a refrigerant gas compression cycle will be described. The low-pressure refrigerant gas circulating through a heat exchanger (not shown) of the air conditioner is drawn into the compression mechanism 2 from the suction pipe 11. The sucked refrigerant gas enters a crescent-shaped compression space (not shown) formed between the fixed scroll 2a and the movable scroll 3, and the orbital movement of the movable scroll 3 causes the crescent-shaped compression space to move from the outside to the center. The refrigerant gas is compressed and discharged from the discharge holes 12 by gradually reducing the diameter toward the center. The compressed gas becomes high-pressure gas, and is once discharged into the discharge space 1 a above the fixed scroll 2 a in the closed container 1, flows through the gas passage 14 into the lower space 1 b in which the electric motor 7 is housed, and Flows into the upper space through a gas passage 15 provided separately from the discharge pipe 16
It is discharged to an air conditioning system such as a heat exchanger. Then, a well-known compression cycle that circulates through a heat exchanger of the air conditioner and returns to the compressor from the suction pipe 11 again is configured.

A circulation cycle for supplying the lubricating oil 9 to each sliding portion will be described. Lubricating oil 9 sucked up in oil sump 10
Rises in the through hole 13 of the shaft 5, lubricates and cools the eccentric bearing 6, the journal bearing 6a, and each sliding portion, and the oil is discharged from the lower portion of the journal bearing 6a to the stator 7 through the oil outlet.
b to form a lubrication cycle which returns to the sump 10 through the passage 18 of the stator 7b.

[0008] In the above-mentioned conventional configuration, the shaft 5 is made of a gray cast iron material or S45C, and the surface of the sliding portion is subjected to a surface hardening treatment by induction hardening so that the surface hardness becomes about Hv60.
It was 0. Further, a gray cast iron material is used for the bearing member 6, and an annular bush material 8a of the journal bearing 6a is
Metal bearing material with back metal was used. The metal bearing material with a back metal is a steel plate having a thickness of about 1.3 to 1.8 mm used as a back metal, and a bearing metal layer is formed on the upper surface of the steel sheet. The bearing metal layer includes a copper alloy, an aluminum alloy,
Lead-based white metals and those containing hard substances such as carbon dispersed therein have been used.

[0009]

In the above-mentioned conventional configuration,
A radial load acts on the orbiting scroll due to gas pressure, inertia, and the like in the compression chamber. This load rotates in a direction substantially the same as the rotation of the shaft 5, and is supported from the eccentric bearing 3 a to the eccentric shaft 5 a and via the shaft 5 by the journal bearing 6 a. That is, when rotating, the shaft 5 made of cast iron material is slid while being pressed against the inner peripheral surface of the journal bearing 6a by an extremely large load generated by gas compression or the like when the shaft 5 is rotated.

Therefore, under severe operating conditions or operating conditions of high differential pressure with a refrigerant gas (HFC410A, carbon dioxide, etc.) as a substitute for the conventional chlorofluorocarbon HCFC, an excessive load is generated by gas compression, and the journal bearing 6a and the shaft 5
Between them, the lubricating oil film becomes very thin, and a boundary lubrication state in which the lubricating oil film partially contacts. When the boundary lubrication state continues, there has been a problem that the hard material contained in the bearing metal layer causes abrasion of the hardened layer on the induction hardened surface of the shaft 5. In addition, there has been a problem that the sliding loss is large and the efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and provides a hermetic compressor having a high wear resistance and a low sliding loss, and using the same and having high reliability and efficiency. The purpose is to do.

[0012]

According to a first aspect of the present invention, there is provided an electric motor comprising a stator and a rotor in a closed container, and a motor driven by a shaft to which the rotor is fixed. In the hermetic compressor accommodating the compression mechanism section, the shaft is made of Al, Cr, V, Mo, Ti,
Manufactured from a material containing at least one component of Si of 0.2% or more and having a modulus of longitudinal elasticity of 190 GPa or more, manufactured by a finishing process and a nitriding process of nitriding the finished surface, and having a surface hardness of Hv 1000 or more A hermetic compressor characterized by the following.

According to a second aspect of the present invention, there is provided a hermetic compressor including an electric motor including a stator and a rotor in a closed container and a compression mechanism driven by a shaft to which the rotor is fixed. The shaft is made of Al, Cr, Mo,
A finishing process, a nitriding process for nitriding the finished surface, and a surface layer having a thickness of 2 μm containing a material containing at least one component of V, Ti, and Si in an amount of 0.2% or more and having a modulus of longitudinal elasticity of 190 GPa or more. A hermetic compressor manufactured by a surface polishing step of polishing in the following range and having a surface hardness of Hv1000 or more.

The invention according to claim 3 is characterized in that the surface is induction hardened in a quenching step, and then the finishing step and the nitriding step are performed. It is a hermetic compressor of the description.

[0015] The invention according to claim 10 is characterized in that HFC, HC,
The hermetic compressor according to any one of claims 1 to 9, wherein the refrigerant has one of carbon dioxide as a main component.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

In the structure of the scroll compressor used in one embodiment of the present invention, the same functional parts as those of the prior art described with reference to FIG. 6 are denoted by the same reference numerals, and the same structure and operation will not be described. I will omit it.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the vicinity of a sliding surface of a compressor shaft according to the present invention. Similarly, FIG. 2 is a manufacturing process diagram of the compressor shaft of the first embodiment, and FIG. FIG. 4 is a diagram used to describe the hardness distribution of the shaft section afterward, and FIG.

The major difference between this embodiment and the conventional example lies in the shaft used. That is, the surface hardness of the shaft,
Materials and manufacturing process to realize it. Hereinafter, a manufacturing method and a form of the shaft will be described.

FIG. 1 is a cross-sectional view showing the vicinity of the surface of the manufactured shaft 5. The material used is a nitrided steel containing Al, which is JIS-specified SACM645. As shown in FIG. 1, a thickness δ1 (for example, about 8 μ
m), a dense nitrogen compound layer is formed thereon, and a nitrogen diffusion layer having a thickness of δ2 (for example, about 300 μm) is further formed thereunder. The surface hardness is Hv1000 or more (see (Table 1)). . FIG. 3 shows the hardness distribution of the cross section (process specification 1).
(See the curve of).

According to the manufacturing process shown in FIG. 2, the shaft material subjected to heat treatment such as annealing is roughly processed into a shape of a design drawing in a roughing process, and then finished in a shape of a design drawing in a finishing process. Then, the shaft is completed by nitriding the finished surface.

In the nitriding treatment, it is better to carry out the nitriding temperature as low as possible so as not to cause distortion, etc.
It is necessary to form a nitrogen compound in the surface layer so as to be not less than v1000. In this embodiment, the pretreatment gas is FN
3 (nitrogen trifluoride) is used to reduce the oxide film on the nitrided surface to perform gas nitriding, and the nitriding is performed at a low temperature of 410 ° C.

In this embodiment, since the compound surface after the nitriding step is used as it is for the sliding surface, the surface roughness after finishing is important. Therefore, after finishing to the surface roughness (for example, Ra0.2) specified in the design drawing by grinding or the like in the finishing process, nitriding is performed.

Table 1 shows the surface hardness of the shaft and the amount of wear of the shaft after the compressor was operated under severe test conditions when the material was manufactured by the above-mentioned method while changing the material and the presence or absence of nitriding. The table shows that S4 which was induction hardened without nitriding
5C and the surface hardness of SCM415 which is carburized induction hardened,
Looking at the wear amount, the surface hardness is 613 and 824, respectively, and the wear amount is large.

[0025]

[Table 1]

In addition, S manufactured by nitriding in the above process is manufactured.
In the case of 45C, the surface hardness is Hv1000 or less (Hv8
04) and the amount of wear is large.
In the case of 5, the surface hardness is Hv1000 or more (Hv1077).
The wear amount was remarkably small, and the wear resistance was improved.

This is because Al contained in SACM 645,
This is because Cr and Mo easily form a nitrogen compound having high hardness. Fig. 4 shows the relationship between the amount of elements that easily form nitride compounds and hardness (Lubrication Handbook, P546, 1987, Yokendo)
It shows. The effects of Al and Cr are very large.
It can be seen that Mo, V, Mn, and Si also have a relatively large effect on improving the surface hardness. Although not shown in FIG. 4, Ti has the same effect. With carbon steel such as S45C, which hardly contains these elements, the surface hardness could not be increased to Hv1000 or more by nitriding.
Further, the maximum surface hardness only by quenching with carbon steel is about Hv830, and cannot exceed Hv1000. However, Al, Cr, Mo, V, M
Hv 1000 or more is possible by nitriding an alloy containing elements such as n, Si, and Ti.

There is also a difference in the surface hardness due to nitriding depending on the combination of the contents of these elements. Due to the ease of nitriding and productivity, overseas (Germany, UK, etc.) (Table 2), (Table 3) The nitriding steels having the compositions shown in the following are produced. By selecting the optimal nitriding conditions using these nitriding steels, a shaft having a surface hardness of Hv 1000 or more can be manufactured. The element composition of SACM645 is included in 1) in (Table 2).

[0029]

[Table 2]

[0030]

[Table 3]

Further, even if it is not the above-mentioned dedicated nitriding steel, an alloy steel containing a large amount of Cr from the viewpoint of nitriding in FIG. 4, for example, a die alloy tool steel tool containing 2.00% to 15.00% Even with steel, martensitic steel containing 11.50% to 18.00% of Cr and precipitation hardening stainless steel containing 15.00% to 18.00%, a hard compound layer can be formed under nitriding conditions, and the surface hardness is Hv 1000 or more. Shafts can be manufactured. These materials have the advantage of being relatively readily available. However, in terms of cost and ease of nitriding, the aforementioned nitriding steel is more advantageous. In addition, the use of steel for nitriding is advantageous in that Hv1
A surface hardness of more than 000 can be obtained. Therefore, it is possible to suppress deformation in the nitriding process such as bending, deflection, and dimensional change of the shaft, and it is possible to obtain a shaft with high accuracy and high wear resistance.

Table 4 shows the surface hardness and the amount of wear when the thickness of the nitrogen compound layer shown in FIG. 1 was changed. When the film thickness δ1 of the compound layer is 8 μm and 3 μm, even if the surface hardness is almost the same, if the film thickness is small, the amount of wear increases. Therefore, the film thickness must be at least 5 μm or more. However, even if the film thickness is too large, cracks are likely to occur because the surface hardness is hard. Therefore, the film thickness should be at most 20 μm or less.

[0033]

[Table 4]

The shaft materials described above are made of Al, Cr, V, Mo, Ti, Si, which easily form a compound with nitrogen.
Containing at least one component of 0.2% or more,
Further, the modulus of longitudinal elasticity containing 0.1 to 0.45% of C is 19
It is an alloy steel having 0 GPa or more. By manufacturing the shaft 5 from a material having a modulus of longitudinal elasticity of 190 GPa or more higher than that of the cast iron material as described above, it is possible to reduce the deflection generated in the shaft 5 even under severe operating conditions, etc. As a result, it is possible to prevent the deterioration of the sliding conditions due to the above-mentioned factors, to improve the reliability, and to reduce the loss in the bearings.

According to the present embodiment, it is possible to prevent the wear of the surface of the shaft 5 which has conventionally occurred under severe operating conditions and the like, and it is possible to reduce the sliding loss. A high scroll compressor can be realized.

(Embodiment 2) Next, Embodiment 2 will be described.
This will be described with reference to FIGS. FIG. 3 is a hardness distribution of a cross section of the shaft after the nitriding process, and FIG.

The difference from the second embodiment is that an induction hardening process is added before the finishing process in the shaft manufacturing process as in the process specification 2 shown in FIG. In FIG.
The curve of the cross-sectional hardness distribution produced in the process specification 2 shows the results of the surface hardness of the shaft prepared in Table 4 and the amount of wear of the shaft after the compressor was operated under severe test conditions.

By adding this induction hardening step, the hardness distribution of the shaft changes as shown in FIG. 3, and higher hardness can be obtained to a deeper part than in the case of the process specification 1. By adopting such a hardness distribution, it becomes possible to receive the load during the operation of the compressor not only on the extreme surface of the shaft but also on the entire thickness direction including the deeper portion, thereby improving the wear resistance. Can be done.

Referring to Table 4, although the surface hardnesses of the process specifications 1 and 2 are almost the same, the wear amount is smaller in the process specification 2 and the wear resistance is improved.

In this embodiment, the same effect as in the embodiment can be obtained by using the alloy steel material described in the first embodiment, and a high hardness distribution can be obtained to a deep portion. A shaft with higher wear resistance, that is, a highly reliable shaft can be obtained. By using this shaft, a highly reliable and efficient scroll compressor can be realized.

(Embodiment 3) Next, Embodiment 3
Will be described with reference to FIGS. FIG. 5 shows a third embodiment.
FIG.

The difference from the first and second embodiments is that, as shown in the process specification 3 shown in FIG.
The point is that a polishing process is added after the nitriding process.

Table 5 shows the results of the wear amount of the shaft.

[0044]

[Table 5]

Here, after the nitriding step, the surface of the compound layer 21 (see FIG. 1) is polished using polishing cloth to improve the roughness of the surface of the compound layer 21.
The surface roughness of the compound layer formed by the nitriding treatment is roughly the same as the surface roughness at the time of finishing when the thickness is small, but the surface roughness tends to become worse as the compound layer becomes thicker. is there. Therefore, the compound layer 21 is polished.
By smoothing the minute projections on the surface layer of the above and improving the surface roughness, the amount of wear of the shaft can be further reduced. At the same time, damage to the bearing on which the shaft slides can be reduced, so that the sliding loss can be reduced. The polishing allowance of the compound layer in this polishing is at most about 2 μm, which is a sufficient effect.

As described above, according to the third embodiment, the surface roughness can be improved after the nitriding treatment and a highly reliable shaft having high wear resistance can be obtained as compared with the first and second embodiments. Further, the scroll compressor using this shaft can realize higher reliability and higher efficiency than the first and second embodiments.

Before the finishing process of process specification 3,
By adding the induction hardening step as in the second embodiment, it is possible to further improve the wear resistance and reduce the sliding loss, so that the scroll compressor using this shaft can realize high reliability and efficiency.

Although all of the above embodiments have been described with reference to the case of a scroll compressor, similar effects can be obtained when the shaft is used as a shaft of another compressor such as a reciprocating compressor or a rotary compressor. .

In all of the above embodiments, the nitriding method is not limited to the above embodiment, and the surface hardness Hv is not limited to other gas nitriding methods, gas nitrocarburizing methods, salt bath nitriding methods, oxynitriding methods, and the like.
It is needless to say that reliability and efficiency can be improved by forming more than 1000 nitride compound layers as in the embodiment.

In all of the above embodiments, H
FC134a, HFC410A, hydrocarbon (H
C) and other chlorine-free refrigerants, carbon dioxide and conventional H
Even when a refrigerant such as the CFC 22 is used in a refrigeration and air-conditioning cycle device, it is needless to say that the reliability and efficiency can be improved by adopting the shaft of the present embodiment similarly to the embodiment.

In all of the above-described embodiments, even when an ester oil or an ether oil compatible with the HFCs refrigerant is used as the refrigerating machine oil, the embodiment of the present invention can be applied by adopting the shaft of the present embodiment. It goes without saying that reliability and efficiency can be improved in the same manner as described above.

In all of the above embodiments, when HC refrigerant is used as the refrigerant and mineral oil or alkylbenzene oil having high solubility in the HC refrigerant is used as the refrigerating machine oil, the viscosity of the refrigerating machine oil decreases remarkably, and Although the sliding conditions of the bearing become more severe, the use of the shaft of the present embodiment makes it possible to improve the wear resistance and obtain high reliability. When a carbon dioxide refrigerant is used as the refrigerant, the load applied to the bearing becomes extremely large, so that the sliding conditions of the journal bearing become more severe. It goes without saying that the reliability and efficiency can be improved as in the case of the embodiment.

In all of the above embodiments, as the bearing that slides with the shaft, for example, carbon is used for the bush material, a resin composite bearing material with a back metal, a metal bearing material with a back metal, or Even when a cast iron bearing material is used, reliability and efficiency can be improved as in the embodiment. Further, the resin composite bearing material with a back metal may of course be a material in which a resin layer is impregnated in a porous sintered layer formed on the back metal.

[0054]

As is clear from the above embodiment, according to the first aspect of the present invention, the formation of a dense and hard nitrogen compound allows the sliding portion to have a surface hardness exceeding Hv1000. Thus, a shaft having high wear resistance can be manufactured, and abrasion of the surface of the shaft 5 which has conventionally occurred under severe operating conditions and the like can be prevented, and deflection can be reduced. Therefore, the reliability and efficiency of the hermetic compressor can be improved by using the shaft.

According to the second aspect of the present invention, by adding the induction hardening step, a higher hardness can be obtained even deeper. By adopting such a hardness distribution, it becomes possible to receive the load during the operation of the compressor not only on the extreme surface of the shaft but also on the entire thickness direction including the deeper portion, thereby improving the wear resistance. And a more reliable and efficient hermetic compressor and its shaft can be realized.

According to the third aspect of the present invention, by adding the polishing step, the surface roughness of the shaft after the nitriding treatment can be improved, so that the wear resistance can be further improved and the reliability can be improved. A highly efficient and efficient compressor and its shaft can be realized.

According to the tenth aspect, the HFC1
34a, HFC410A, chlorine-free refrigerants such as hydrocarbons (HC), carbon dioxide, and conventional HCFCs.
Even when a refrigerant such as No. 22 is used in a refrigeration and air conditioning cycle device, or under severe operating conditions, wear of the shaft can be prevented. Therefore, the reliability and efficiency of the hermetic compressor can be improved by using the shaft.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view near a sliding surface of a shaft.

FIG. 2 is a manufacturing process diagram of a compressor shaft according to the first embodiment.

FIG. 3 is a diagram showing a hardness distribution of a cross section of a shaft after a nitriding process.

FIG. 4 is an explanatory view of a shaft material.

FIG. 5 is a manufacturing process diagram of a compressor shaft according to the second and third embodiments.

FIG. 6 is a longitudinal sectional view of a conventional scroll compressor.

[Explanation of symbols]

 5 Shaft 21 Compound layer 22 Diffusion layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22C 38/00 302 C22C 38/00 302Z 38/18 38/18 (72) Inventor Hiroshi Hasegawa Kadoma-shi, Osaka 1006 Oaza Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Fumitoshi Nishiwaki 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Inside the company (72) Inventor Hideto Oka 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Mototaka Ezumi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. 3H003 AA05 AB03 AD01 CA01 3H02 9 AA02 AA04 AA14 AB03 BB31 BB44 CC16 CC38 3H039 AA03 AA06 AA12 BB04 BB05 BB07 CC12 CC35 CC36

Claims (10)

[Claims] 1. A hermetic compressor in which an electric motor including a stator and a rotor is housed in a closed container and a compression mechanism section driven by a shaft to which the rotor is fixed, wherein the shaft is made of Al, Cr, V, Mo, Ti, Si at least one component of 0.2% or more, the longitudinal elastic modulus is 1
Manufactured from a material of 90 GPa or more,
A hermetic compressor manufactured by a nitriding process for nitriding the finished surface and having a surface hardness of Hv1000 or more. 2. A hermetic compressor containing an electric motor including a stator and a rotor in a closed container and a compression mechanism driven by a shaft to which the rotor is fixed, wherein the shaft is made of Al, Cr, Mo, V, Ti, Si at least one component of 0.2% or more, the longitudinal elastic modulus is 1
A finishing step, a nitriding step for nitriding the finished surface, and a surface layer of 2 μm with a material of 90 GPa or more.
A hermetic compressor manufactured by a surface polishing step of polishing in the following range and having a surface hardness of Hv1000 or more. 3. The hermetic compression machine according to claim 1, wherein the surface is induction-hardened by a quenching process, and then is manufactured through a finishing process and a nitriding process. Machine. 4. The hermetic compressor according to claim 1, which has a compound layer having a thickness of 5 μm to 20 μm on the surface. 5. A nitride steel containing 0.70% to 1.30% of Al, 1.00% to 1.80% of Cr, and 0.10% to 0.5 of Mo. The hermetic compressor according to any one of claims 1 to 4. 6. A martensitic stainless steel containing 11.50% to 18.00% of Cr.
5. The hermetic compressor according to any one of 4. 7. The hermetic compressor according to claim 1, wherein the hermetic compressor is made of precipitation hardening stainless steel containing 15.00% to 18.00% of Cr. 8. The hermetic compressor shaft according to claim 1, wherein said shaft is made of alloy tool steel for a mold containing 2.00% to 15.00% of Cr. 9. The hermetic compressor according to claim 1, wherein the compression mechanism is a scroll type. 10. The hermetic compressor according to any one of claims 1 to 9, wherein the hermetic compressor is used as a refrigerant mainly containing any one of HFC, HC, and carbon dioxide.