JP5199728B2 - Rotary compressor - Google Patents

Description

  The present invention relates to a rotary compressor used in a refrigerator or an air conditioner, and more particularly to a small and high performance rotary compressor.

A rotary compressor used in a normal refrigerator or air conditioner includes a compression mechanism and an electric motor that drives the compression mechanism in a sealed container. One end of the crankshaft is connected and fixed to the rotor of the electric motor, and the other end of the crankshaft is provided with a rolling piston that rotates eccentrically in the cylinder of the compression mechanism.
The crankshaft is supported by a first bearing and a second bearing installed with a cylinder of the compression mechanism interposed therebetween.

As a bearing structure for supporting a crankshaft in a rotary compressor, there is a journal bearing in which the crankshaft is supported via a lubricating oil film. The crankshaft rotates while being strongly pressed against the inner surface of the journal bearing by a large load generated by the compression of the refrigerant.
At this time, if the contact surface between the crankshaft and the journal bearing is completely smooth, a fluid film having a film thickness according to the theory of fluid lubrication is formed, and lubrication with a continuous fluid film is performed until the film thickness is about the molecular layer. However, actual crankshafts and journal bearings have irregularities and undulations on the surface. If the surfaces with irregularities and undulations come close to each other, even if the average film thickness of the lubricating oil is quite large, the transition from fluid lubrication to mixed lubrication, and further to boundary lubrication occurs. There was a problem that the frictional resistance and the amount of wear increased.

  In order to evaluate the lubrication (bearing characteristics) on the contact surface between the crankshaft and the journal bearing, the oil film thickness parameter Λ (the oil film thickness h obtained as a smooth surface and the synthetic roughness) expressed by the following equation (1) Is a ratio to σ). In this oil film thickness parameter Λ, boundary lubrication occurs completely in the region of Λ ≦ 1, and fluid lubrication can be expected from mixed lubrication when Λ> 1.

  Therefore, as a rotary compressor that solves the problem of increased frictional resistance and wear between the journal bearing and crankshaft, the main shaft (corresponding to the crankshaft) is made of gray cast iron FC250 and steel materials S45C and SCM415, and the main shaft is supported. The journal bearing provided in the bearing component (equivalent to the second bearing) uses a carbon bush material, polyimide bush material, resin composite bearing material with backing metal, etc., and the oil film thickness of the bearing characteristics of the main shaft and journal bearing The parameter Λ is set to Λ> 3.3, the surface roughness Ra of the main shaft in the journal bearing portion is set to Ra ≦ 0.2, and the surface roughness Ra of the journal bearing is set to Ra ≦ 0.3. (For example, refer to Patent Document 1).

In addition, the rotary compressor has a problem that, as the refrigerant is highly compressed due to high performance, the load applied to the crankshaft increases, and the crankshaft is greatly bent.
In order to prevent this increase in the deflection of the crankshaft, it is necessary to increase the rigidity of the crankshaft. One way to increase the rigidity of the crankshaft is to increase the shaft diameter.
However, in this method, the material used increases due to the increase in the size of the compressor, the contact speed between the crankshaft and the bearing increases, the friction increases and the sliding loss increases. There was a problem that the amount of wear increased.

  As a rotary compressor that solves this problem and increases the crankshaft rigidity without increasing the shaft diameter, an upper bearing (corresponding to the first bearing) and a lower bearing (corresponding to the second bearing) are used. Using a simple bearing structure of a sliding bearing type, the shaft (equivalent to a crankshaft) is made of steel pipe to increase rigidity, and a wear-resistant layer such as pearlite, martensite, and bainite is provided on the surface. A shaft that has been subjected to manganese phosphate treatment or molybdenum disulfide treatment as a final surface treatment after grinding and finishing the shaft is disclosed (for example, see Patent Document 2).

JP 2001-289169 A JP 2000-227083 A

In the rotary compressor described in Patent Document 1, the cast iron material FC250 and the steel materials S45C and SCM415 are shown on the crankshaft. With respect to the increase in load applied to the crankshaft as the performance of the rotary compressor increases. However, the use of steel with a high Young's modulus can be expected to prevent the crankshaft from being bent. However, parts such as carbon bushing, polyimide bushing, and resin composite bearings with backing metal are required as bearing materials, which increases costs. Became a problem.
In addition, the rotary compressor described in Patent Document 2 uses a steel pipe whose surface is heat treated, nitrided or carburized to improve rigidity, so that the shaft diameter of the crankshaft is not increased. Both have sufficient rigidity and small deflection of the crankshaft. In addition, the surface of the crankshaft that has been heat-treated, nitrided or carburized is further ground and buffed, and then treated with solid-lubricated manganese phosphate or molybdenum disulfide to provide sliding bearings. Improves wear resistance.

In an actual operation state of a compressor using a journal bearing, the shaft rotational speed is low at the time of starting and stopping, so that the oil film reaction force in the journal bearing is reduced and the oil film thickness is also reduced. In particular, at the time of start-up, since the supply of the lubricating oil is also delayed, direct contact between the surface of the journal bearing and the surface of the crankshaft occurs.
Therefore, when a journal bearing is used in the rotary compressor described in Patent Document 2, the journal bearing surface and the crankshaft surface are in direct contact at the time of start and stop, so the manganese phosphate coating provided on the surface of the crankshaft or the like is worn molybdenum disulfide film, a surface subjected to heat treatment or nitriding treatment and carburization of the crank shaft is exposed.
The surface of the crankshaft that has been subjected to heat treatment, nitriding treatment, or carburizing treatment has a high hardness and a large hardness difference with the journal bearing, causing wear of the journal bearing to proceed. As a result, the surface roughness of the bearing increases, the fluid lubrication state shifts to the mixed lubrication state or the boundary lubrication state, and there is a problem that the reliability of the compressor is lowered, such as burning of the journal bearing.

  The present invention has been made to solve the above-described problems. Even if the load applied to the crankshaft increases as the performance increases, the crankshaft is not enlarged. In addition, the journal bearing that supports the crankshaft is well lubricated without adding bearing members such as carbon bushing, polyimide bushing, and resin composite bearings with a backing metal to the bearing. It is to obtain a rotary compressor with less wear of the journal bearing.

  A first rotary compressor according to the present invention includes an electric motor and a compression mechanism built in a sealed container, and the compression mechanism is connected and fixed to a cylinder, a rolling piston provided in the cylinder, and a rotor of the electric motor. And a journal bearing for supporting the crankshaft provided on each of the upper surface and the lower surface of the cylinder. The rolling piston is eccentrically attached to the crankshaft, and a part of the outer peripheral surface of the rolling piston is inside the cylinder. A rotary compressor that rotates in a compression chamber in sliding contact with a peripheral surface, wherein the crankshaft is made of steel for machine structural use, and a martensite layer or a surface of a portion of the crankshaft that slides at least on a journal bearing Nitride layer and manganese phosphate skin formed on the surface of martensite layer or nitride layer When, a molybdenum disulfide film formed on the surface of the manganese phosphate film, the surface roughness of the martensitic layer or nitride layer of the crankshaft, is smaller than the surface roughness of the journal bearing.

  In a second rotary compressor according to the present invention, the crankshaft is made of mechanical structural steel, and a martensite layer or a nitride layer is provided on the surface of at least a portion of the crankshaft that slides on the journal bearing. And a molybdenum disulfide film formed on the surface of the layer or nitride layer, and the surface roughness of the martensite layer or nitride layer of the crankshaft is smaller than the surface roughness of the journal bearing.

  A first rotary compressor according to the present invention includes an electric motor and a compression mechanism built in a sealed container, and the compression mechanism is connected and fixed to a cylinder, a rolling piston provided in the cylinder, and a rotor of the electric motor. And a journal bearing for supporting the crankshaft provided on each of the upper surface and the lower surface of the cylinder. The rolling piston is eccentrically attached to the crankshaft, and a part of the outer peripheral surface of the rolling piston is inside the cylinder. A rotary compressor that rotates in a compression chamber in sliding contact with a peripheral surface, wherein the crankshaft is made of steel for machine structural use, and a martensite layer or a surface of a portion of the crankshaft that slides at least on a journal bearing Nitride layer and manganese phosphate skin formed on the surface of martensite layer or nitride layer And a molybdenum disulfide film formed on the surface of the manganese phosphate film, and the surface roughness of the martensite layer or nitride layer of the crankshaft is smaller than the surface roughness of the journal bearing. Even if the applied load increases, it is possible to prevent an increase in crankshaft deflection without increasing the size of the crankshaft, and to provide a rotary compressor with good lubrication and low wear on the journal bearing that supports the crankshaft. Can be obtained.

  In a second rotary compressor according to the present invention, the crankshaft is made of mechanical structural steel, and a martensite layer or a nitride layer is provided on the surface of at least a portion of the crankshaft that slides on the journal bearing. And a molybdenum disulfide film formed on the surface of the layer or nitride layer, the surface roughness of the martensite layer or nitride layer of the crankshaft is smaller than the surface roughness of the journal bearing, and is applied to the crankshaft Even if the load increases, without increasing the size of the crankshaft, an increase in crankshaft deflection can be prevented, and a journal compressor supporting the crankshaft is lubricated with good wear and a rotary compressor with low wear. be able to.

Embodiment 1 FIG.
FIG. 1 is a schematic sectional view of a rotary compressor according to Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram of the AA cross section in the schematic cross-sectional view shown in FIG. 1 of the rotary compressor according to the first embodiment of the present invention.
As shown in FIGS. 1 and 2, the rotary compressor 100 according to the present embodiment includes an electric motor 11 and a compression mechanism 9 in a sealed container 21 formed by an upper shell 19 and a lower shell 20. . The upper shell 19 is provided with a discharge pipe 10 for discharging the refrigerant.
The compression mechanism 9 includes a first bearing 13, a U cylinder 15, a middle plate 16, an L cylinder 17, and a second bearing 18, which are formed by the first bearing 13 and the middle plate 16. A compression chamber 25 and a second compression chamber 26 formed by the second bearing 18 and the middle plate 16 are provided.

A rolling piston 14 is installed in each of the first compression chamber 25 and the second compression chamber 26. Each rolling piston 14 is connected and fixed to the rotor of the electric motor 11 and is eccentrically attached to the crankshaft 12 supported by the first bearing 13 and the second bearing 18. The rotation of the crankshaft 12 causes each rolling piston 14 to rotate while being in sliding contact with the inner peripheral surfaces of the U cylinder 15 and the L cylinder 17 corresponding to a part of the outer peripheral surface thereof.
In addition, the U cylinder 15 and the L cylinder 17 are provided with vanes 23 that can appear and disappear from the inside in grooves formed in the radial direction. The vane 23 is in sliding contact with the outer circumferential surface of the rolling piston 14 even when the rolling piston 14 is rotated by the action of a spring 24 provided in the groove.
The U cylinder 15 and the L cylinder 17 are each provided with a suction pipe 22 for sucking refrigerant.
In the rotary compressor 100 of the present embodiment, there are two compression chambers, but the present invention is not limited to this.

  In the rotary compressor 100 of the present embodiment, journal bearings are used for the first bearing 13 and the second bearing 18, and the crankshaft 12 is replaced with the conventional spheroidal graphite cast iron DCD550 having a Young's modulus of about 160 GPa. For example, chrome molybdenum steel SCM435, which is an alloy for mechanical structures having a Young's modulus of 210 GPa, is used. Since the SCM material has high hardness and has a relatively small elongation that serves as a measure of toughness, the conformability due to wear is relatively good.

FIG. 3 is a schematic cross-sectional view showing the configuration of the surface of the crankshaft used in the rotary compressor according to Embodiment 1 of the present invention.
As shown in FIG. 3, the surface of the crankshaft 12 in the present embodiment is surface-treated to form a plurality of layers made of different materials.
That is, a nitride layer 42 whose surface is superfinished with a polishing film is provided on the surface of the metal base material 43, and a manganese phosphate coating 41 that is buffed on the surface of the nitride layer 42. And a molybdenum disulfide film 40 is provided on the surface of the manganese phosphate film 41.

The thickness of the layer and the film constituting the surface of the crankshaft 12 of the present embodiment are 10 μm to 20 μm for the nitride layer 42, 2 μm to 5 μm for the manganese phosphate film 41, and about 1 μm for the molybdenum disulfide film 40. .
Further, in the crankshaft 12 of the present embodiment, the surface roughness of the surface of the metal base material after grinding processing is about 1.5 μm, but the surface roughness of the surface of the nitride layer 42 immediately after nitriding is As shown in the measurement result example of FIG. 4, it was about 2.5 μm. Therefore, the nitride layer 42 was superfinished, and the surface roughness after the superfinishing was smaller than about 0.7 μm as shown in the measurement result example of FIG.
That is, the surface of the nitride layer 42 of the crankshaft 12 including the nitride layer 42 subjected to the superfinishing process was considerably smooth as shown in the schematic cross-sectional view of the crankshaft in FIG.
Therefore, as shown in FIG. 3, the manganese phosphate film 41 formed on the surface of the nitride layer 42 and the molybdenum disulfide film 40 formed on the surface of the manganese phosphate film 41 also have a surface roughness. Is very small.

Next, a method for forming a layer and a film constituting the surface of the crankshaft 12 in the present embodiment will be described.
The metal base material of the crankshaft 12, that is, the SCM435 material, which is an alloy for machine structure, is subjected to a grinding finish to smooth the surface.
Formation of the nitride layer 42 for improving the wear resistance of the metal base material surface of the crankshaft 12 is performed by salt bath nitriding treatment of the crankshaft 12 at a treatment temperature of 480 ° C. to 580 ° C. Since this processing temperature is sufficiently lower (480 ° C.) than the transformation temperature (900 ° C. or higher) of the steel material, the shape accuracy of the crankshaft 12 is hardly deteriorated, and the surface hardness of the crankshaft 12 is Vickers hardness Hv. = 800 or so.

As described above, since the surface roughness of the nitride layer 42 formed by the salt bath nitriding process is as large as about 2.5 μm, the nitride layer 42 is superfinished. Specifically, the crankshaft 12 as a workpiece is attached to a lathe and rotated, and the lapping film on which the abrasive grain layer is formed is pressed against the crankshaft 12 by a resin roller or the like to polish the surface of the crankshaft 12. To do. As abrasive grains for polishing film, No. 2000 with coarse processing abrasive grains (abrasive grain size 9 μm), No. 2000 film with abrasive grains for finishing (abrasive grain size 9 μm), No. 4000 film with abrasive grains for finishing (abrasive) Three types of wrapping films having a particle diameter of 3 μm) are used stepwise.
The polishing amount of the nitride layer 42 by the superfinishing process is about 1 μm to about 2 μm in radius, and the thickness of the nitride layer 42 is 10 μm to 20 μm. Remaining.
In the present embodiment, the superfinishing method using a wrapping film has been described, but other superfinishing methods can be used as long as the surface roughness can be reduced to a predetermined surface roughness, which is limited to the superfinishing method using a wrapping film. is not.

Formation of the manganese phosphate coating 41 on the smoothed nitride layer 42 surface involves immersing the crankshaft 12 in a manganese phosphate bath, etching the iron on the surface of the crankshaft 12, and forming manganese phosphate crystals. Precipitate and perform. Since the deposited manganese phosphate crystal has a size of about 1 μm to about 2 μm, the surface immediately after the formation of the manganese phosphate film 41 becomes uneven. Therefore, after forming the manganese phosphate film 41, the surface irregularities are smoothed by buffing or the like.

The molybdenum disulfide film 40 is formed by spraying molybdenum disulfide powder onto the surface of the manganese phosphate film 41 by shot blasting. The formed molybdenum disulfide film 40 does not contain a binder component such as a resin. Further, the molybdenum disulfide coating 40 is formed only at two locations on the crankshaft 12, a portion supported by the first bearing 13 and a portion supported by the second bearing 18.

  Next, the rotary compressor of this embodiment will be described in detail by way of examples.

Example 1.
In the rotary compressor 100 of the present embodiment, the diameter of the crankshaft 12 is maintained at 16 mm of the conventional rotary compressor, the heights of the U cylinder 15 and the L cylinder 17 are increased, and the capacity of the compression chamber is increased. This is an increase of about 13% from 172cc to 194cc.
In order to cope with an increase in load on the crankshaft 12 due to high compression of the rotary compressor 100, the crankshaft 12 has a Young's modulus of about 210 GPa instead of the conventional spheroidal graphite cast iron FCD550 of about 160 GPa. The chromium-molybdenum steel SCM435, which is about 31% higher in mechanical structure, is used.
In the rotary compressor 100 of the present embodiment, since a material having a higher Young's modulus increase rate than the increase rate of the compression chamber capacity is used for the crankshaft 12, bending of the crankshaft 12 Can be smaller than the deflection of the crankshaft.

  In this embodiment, the effective length of the first bearing 13, which is a journal bearing, is 30 mm, and the effective length of the second bearing 18 is 19.6 mm. The distance between the center of gravity of the first bearing 18 and the center of gravity of the second bearing 13 is 76.2 mm, and the distance from the center of gravity of the second bearing 18 to the load point of the L cylinder 17 is 22.9 mm. The distance from the center of gravity of the second bearing 18 to the load point of the U cylinder 15 is 48.2 mm. Moreover, the clearance gap between the crankshaft 12 and each bearing 13 and 18 is 0.019 mm. The journal bearing material is gray cast iron FC250, and its surface has a maximum roughness σb of 1 μm.

  For journal bearings of this size, the load on the crankshaft and the minimum oil film thickness hs at that time were determined based on Patir & Cheng's modified Reynolds equation and Greenwood & Williams solid contact theory. As a result, 1.2 μm was obtained as the minimum oil film thickness hs under the rated operating conditions of the rotary compressor of this example.

  The crankshaft 12 of the rotary compressor 100 of the present embodiment is provided with a surface treatment layer formed by the above method. The surface treatment layer is provided on the surface of the metal base material 43, and the surface is superfinished with a polishing film so that the surface roughness is less than about 0.7 μm, and on the surface of the nitride layer 42. It is formed by a provided manganese phosphate film 41 that has been buffed, and a smooth molybdenum disulfide film 40 provided on the surface of the manganese phosphate film 41.

In order for the journal bearing to operate in the state of fluid lubrication to mixed lubrication, the oil film thickness parameter Λ in the above equation (1) needs to be larger than 1. That is, in the rotary compressor of the present embodiment, the minimum oil film thickness hs in the journal bearing is larger than the combined roughness σc.
That is, in the rotary compressor of this embodiment, in order for the journal bearing to operate while maintaining the state of fluid lubrication to mixed lubrication, the surface roughness σa of the crankshaft satisfies the relationship of the following equation (2). is there.

  By substituting 1.2 μm as the minimum oil film thickness hs and 1 μm as the maximum roughness σb of the journal bearing surface into the above equation (2), the crankshaft surface roughness σa <0.7 μm is obtained. If the crankshaft has a surface roughness of less than 0.7 μm, the journal bearing of this rotary compressor is considered to operate while maintaining the state of fluid lubrication to mixed lubrication.

In the rotary compressor of the present embodiment, the outermost surface of the crankshaft is smooth and the surface roughness can be made smaller than 0.7 μm, and the journal bearing operates while maintaining the state from fluid lubrication to mixed lubrication. .
Further, in the rotary compressor of the present embodiment, even if the surface roughness of the outermost surface of the crankshaft is 0.7 μm or more, for example, the outermost surface layer is a molybdenum disulfide film. Since it is soft with respect to FC250, it adapts to the shape of the bearing by contact and can maintain a fluid lubrication state in a steady state. In particular, the molybdenum disulfide film does not contain a binder component such as resin, so it has a high function as a solid lubricant.In actual operation of a rotary compressor, the shaft rotation speed becomes low at startup and stop, and the oil film in the journal bearing The reaction force becomes smaller and the oil film thickness becomes smaller. In particular, at the time of start-up, since the supply of lubricating oil is also delayed, direct contact between the surface of the journal bearing and the surface of the crankshaft occurs, and the molybdenum disulfide film and the manganese phosphate film wear.
Thus, even if the molybdenum disulfide film and the manganese phosphate film are worn, the surface of the crankshaft becomes a nitride layer surface having wear resistance and a surface roughness of less than 0.7 μm. In this state, the rotary compressor can be operated in a state of fluid lubrication to mixed lubrication.

  Further, the rotary compressor of the present embodiment has a compression chamber larger than the capacity of the compression chamber of the conventional rotary compressor, and the crankshaft has an increase rate of Young's modulus larger than that of the compression chamber. Therefore, even if the rotary compressor is highly compressed, the bending of the crankshaft does not increase.

  In other words, the twin rotary compressor of the present embodiment uses the same gray cast iron FC250 as the conventional bearing, and even if the durability test of the small high-performance compressor is performed, problems such as seizure in the journal bearing occur. In addition, there is almost no wear damage on the bearing, and reliability equivalent to that of a conventional compressor can be ensured even in high compression operation.

Embodiment 2. FIG.
The rotary compressor of the present embodiment is the same as that of the first embodiment except that the configuration of the surface layer of the crankshaft is changed.
FIG. 7 is a schematic cross-sectional view showing the structure of the surface of the crankshaft used in the rotary compressor according to Embodiment 2 of the present invention.
As shown in FIG. 7, in the present embodiment, the surface of the metal base material 43 is provided with a nitride layer 42 whose surface is superfinished with a polishing film, and the surface of the nitride layer 42 is provided on the surface. A molybdenum disulfide film 40 is provided.
The method for forming nitride layer 42 and the method for forming molybdenum disulfide film 40 are the same as in the first embodiment. Further, the surface roughness of the nitride layer 42 is made smaller than about 0.7 μm by superfinishing with a polishing film.

FIG. 8 is an example of measurement results of the surface roughness of the molybdenum disulfide film on the crankshaft used in the rotary compressor according to the second embodiment of the present invention. The surface roughness of the crankshaft 12 is about 1.5 μm, which is larger than the surface roughness with which the bearing of the present embodiment operates while maintaining the state of fluid lubrication to mixed lubrication. Contact occurs.
However, since the molybdenum disulfide film 40 is soft with respect to the bearing material FC250, it is adapted to the shape of the bearing by contact and can maintain a fluid lubrication state in a steady state. Further, even when the wear of the molybdenum disulfide film 40 progresses and the nitride layer 42 is exposed, the maximum roughness is smaller than 0.7 μm, so that the lubrication at the journal bearing is in a state of fluid lubrication to mixed lubrication. Thus, the rotary compressor can be operated, and the wear of the bearing can be reduced.

  Actually, even if the crankshaft 12 of the present embodiment is incorporated in a twin rotary compressor having the same design as that of the first embodiment and the durability test of the small high-performance compressor is performed, the crankshaft is not greatly bent. , No problems such as seizure in journal bearings occur, bearing wear is equivalent to that of the conventional model, high efficiency is achieved by high compression, and the reliability of the journal bearing part is equivalent to that of the conventional model. Can do.

  In the first and second embodiments, the case where the nitride layer is formed in order to improve the wear resistance has been described. However, the martensite layer has a thickness of 450 μm or more by performing a quenching process by a processing method such as induction hardening. The same effect can be obtained even when the crankshaft hardness is HRC50-63 (equivalent to Vickers hardness 513 to 772).

  The rotary compressor according to the present invention can be effectively used as a high-performance, high-compression rotary compressor because the crankshaft has a small deflection and is excellent in lubricity in a journal bearing.

It is a cross-sectional schematic diagram of the rotary compressor concerning Embodiment 1 of this invention. It is the schematic diagram of the AA cross section in the cross-sectional schematic diagram shown in FIG. 1 of the rotary compressor concerning Embodiment 1 of this invention. It is a cross-sectional schematic diagram which shows the structure of the surface of the crankshaft used for the rotary compressor concerning Embodiment 1 of this invention. It is a figure which shows the example of a measurement result of the surface roughness of the nitride layer surface immediately after the nitridation process of the crankshaft used for the rotary compressor concerning Embodiment 1 of this invention. It is a figure which shows the example of a measurement result of the surface roughness of the nitride layer surface after the superfinishing process of the crankshaft used for the rotary compressor concerning Embodiment 1 of this invention. It is a figure which shows the cross-sectional schematic diagram of the crankshaft after superfinishing the nitride layer used for the rotary compressor concerning Embodiment 1 of this invention. It is a cross-sectional schematic diagram which shows the structure of the surface of the crankshaft used for the rotary compressor concerning Embodiment 2 of this invention. It is a figure which shows the example of a measurement result of the surface roughness of the molybdenum disulfide film | membrane of the crankshaft used for the rotary compressor concerning Embodiment 2 of this invention.

Explanation of symbols

10 discharge pipe, 11 electric motor, 12 crankshaft, 13 first bearing,
14 rolling piston, 15 U cylinder, 16 middle plate,
17 L cylinder, 18 second bearing, 19 upper shell, 20 lower shell,
21 closed container, 22 suction pipe, 23 vane, 24 spring,
25 first compression chamber, 26 second compression chamber, 40 molybdenum disulfide film,
41 Manganese phosphate coating, 42 Nitride layer, 43 Metal matrix,
100 Rotary compressor.

Claims (6)

An electric motor and a compression mechanism are built in the sealed container, and the compression mechanism includes a cylinder, a rolling piston provided in the cylinder, a crankshaft connected and fixed to the rotor of the electric motor, and the cylinder. A journal bearing for supporting the crankshaft provided on each of an upper surface and a lower surface, the rolling piston is mounted eccentrically on the crankshaft, and a part of an outer peripheral surface of the rolling piston is an inner peripheral surface of the cylinder A rotary compressor that rotates in a compression chamber in sliding contact with
The crankshaft is made of mechanical structural steel, on the surface of the crankshaft that slides at least with the journal bearing, on the surface of the martensite layer or nitride layer, and on the surface of the martensite layer or nitride layer. The surface of the journal bearing is provided with a formed manganese phosphate film and a molybdenum disulfide film formed on the surface of the manganese phosphate film, and the surface roughness of the martensite layer or nitride layer of the crankshaft is A rotary compressor characterized by being smaller in roughness. An electric motor and a compression mechanism are incorporated in the sealed container, and the compression mechanism includes a cylinder, a rolling piston provided in the cylinder, a crankshaft connected and fixed to a rotor of the electric motor, and an upper surface of the cylinder. And a journal bearing for supporting the crankshaft provided respectively on the lower surface, the rolling piston is mounted eccentrically on the crankshaft, and a part of the outer peripheral surface of the rolling piston is on the inner peripheral surface of the cylinder A rotary compressor that is in sliding contact and rotates in the compression chamber,
The crankshaft is made of mechanical structural steel, on the surface of the crankshaft that slides at least with the journal bearing, on the surface of the martensite layer or nitride layer, and on the surface of the martensite layer or nitride layer. A rotary compressor comprising: a formed molybdenum disulfide film, wherein a martensite layer or a nitride layer of the crankshaft has a surface roughness smaller than a maximum surface roughness of the journal bearing. 3. The surface roughness σa of the martensite layer or nitride layer of at least a portion of the crankshaft that slides with the journal bearing satisfies the relationship of the following formula (2): 3. Rotary compressor.

  The surface roughness σb of the journal bearing is 1 μm, and the surface roughness σa of the martensite layer or nitride layer of at least the portion of the crankshaft that slides with the journal bearing is less than 0.7 μm. The rotary compressor according to claim 1 or claim 2. The rotary compressor according to any one of claims 1 to 4, wherein the molybdenum disulfide film does not contain a binder component such as a resin.   The rotary compressor according to any one of claims 1 to 5, wherein steel for mechanical structure having a Young's modulus increase rate larger than a compression chamber capacity increase rate is used for the crankshaft.

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