JP3729954B2 - Rotary compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary compressor, and more particularly to a rotary compressor with improved vane wear resistance.
[0002]
[Prior art]
In recent years, there has been an increasing need for a rotary compressor to increase the proof stress of a sliding portion, for example, due to the response to NON-CFC having poor lubricity. As an example, FIG. 8 shows a rotary compressor described in JP-A-64-63692. 1 is an airtight container, 2 is an electric motor part, 3 is a compressor part. Reference numeral 4 denotes a vane, 5 denotes a roller, 6 denotes a cylinder, and 7 denotes a shaft. On the surface layer of the vane 4, a skin covering layer in which a metal nitride such as Cr is diffused is formed by ion plating.
[0003]
In the rotary compressor configured as described above, when the compressor unit 3 is driven by the electric motor unit 2, the roller 5 attached to the eccentric part of the shaft 7 is eccentric along the inner wall of the cylinder 6. The vane 4 that rotates and is in contact with the outer peripheral surface of the roller 5 partitions the compression chamber into a high-pressure chamber and a low-pressure chamber and performs compression. At this time, the tip of the vane that is in contact with the outer periphery of the roller is in a severe sliding contact state with line contact. However, the vane is strengthened by forming a skin covering layer on the vane and increasing the surface hardness.
[0004]
After that, surface treatment such as nitriding treatment is further performed before coating, and the hardness of the base is increased to further improve the proof stress, and those described in JP-A-6-93990 are known. FIG. 9 shows a cross-sectional structure of the vane, and the content of nitriding the base material will be described below. Reference numeral 8 denotes a nitriding layer of the vane 4 in which nitrogen is diffused in the base material. Reference numeral 9 denotes a skin covering layer of the vane 4, and a skin covering layer in which a metal nitride such as Cr is diffused is formed on the nitriding layer 8 by ion plating. Prior to the ion plating treatment, ion bombardment treatment is performed for the purpose of improving the adhesion of the skin covering layer. The ion bombardment process and the ion plating process are normally performed continuously in a vacuum vessel. Next, specific processing contents and purposes will be described. The first is ion bombardment, which removes the surface contaminants of the vane using a sputtering effect of gas ions such as argon in a vacuum vessel that has been sucked to a predetermined degree of vacuum, and simultaneously heats the vane to be covered. To do. Next, in the ion plating process, nitrogen gas is introduced into the vacuum container to cause the reaction between the evaporated metal ions and nitrogen to form a skin covering layer on the surface of the vane fixed in the vacuum container.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, in order to improve the adhesion of the skin covering layer, if the ion bombarding time is sufficiently long, the vane temperature is abnormally increased by the sputtering effect and the next ion plating process is started. As for the structure of the skin layer formed by ion plating, the columnar structure has the highest wear resistance, but when the vane temperature becomes abnormally high, crystals of different orientations are generated in the columnar structure. . Since this incomplete columnar structure is easily peeled off in the sliding direction when viewed microscopically, the ceramic layer subjected to such treatment has a problem that wear progresses quickly and wear resistance varies. It was.
[0006]
Further, when a high load is applied to the vane, there is a problem that the skin covering layer is easily cracked and the skin covering layer is missing.
[0007]
On the other hand, in the case where the nitride layer is formed on the base material and the ion plating cover layer is further provided thereon, the nitrogen of the nitride layer is exceeded when the temperature of the ion plating process exceeds the temperature of the nitriding process. Diffuses and the hardness decreases. When the hardness of the nitride layer as the base is lowered, there is also a problem that, when a high load is applied to the vane, the ion plating skin covering layer is easily deformed and at the same time is easily chipped and wear resistance is lowered.
[0008]
The present invention is intended to solve the above-described conventional problems, and an object thereof is to stabilize the durability of the vane at a high level.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is such that the temperature of the vane for ion plating treatment or the like is set to 550 ° C. or less, and the durability of the vane can be stabilized at a high level.
[0010]
Further, the vane temperature during the ion plating treatment is set to be equal to or lower than the temperature during the nitride layer treatment, and the durability of the vane can be stabilized at a higher level.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, the vane forms a CrN coating layer by ion plating after ion bombarding on the nitride layer formed on the surface of the base material. The plating process is performed at a temperature of the vane of 550 ° C. or less and a temperature of the nitride layer or less, and the kinetic energy of evaporated metal atoms and nitrogen atoms reaching the vane surface is low, so that a film is formed. Nuclei of the initial structure are easily formed, and a uniform columnar structure in which the columns are aligned in a certain direction can be generated. In addition, since the hardness of the nitriding layer that is the base of the skin covering layer can be kept high, even when a high load is applied to the vane, the nitride layer supports the skin covering layer to prevent the occurrence of chipping of the skin covering layer, It has the effect of stabilizing the wear resistance of the vane at a higher level.
[0013]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to FIGS. The same parts as those in the conventional example are denoted by the same reference numerals and detailed description thereof is omitted.
[0014]
FIG. 1 shows the structure of the rotary compressor of the present invention, and FIG. 2 shows the sectional structure of the vane of the present invention according to claim 1. 10 is a vane and 11 is a CrN coating layer formed by ion plating. The temperature of the vane during the ion plating process is 550 ° C. Chromium and nitrogen atoms that reach the vane surface at the start of ion plating have high energy and move on the surface. This atom gradually loses energy and is captured in an energetically stable place. At this time, they meet and merge with other atoms. The combined group of atoms continues to grow, and this forms the core of the structure and forms a columnar structure. FIG. 3 (a) shows the cross-sectional structure of the CrN skin layer of this example, and since it is processed at 550 ° C., the kinetic energy is originally low and it is easy to stabilize. Therefore, in order to generate nuclei quickly and continue stable growth, it is formed with a uniform columnar structure in which columns are dense and aligned in a certain direction.
[0015]
FIG. 3 (b) shows a cross-sectional structure of a conventional CrN skin layer. Since the CrN coating process is performed in a state where the vane temperature is abnormally high, the kinetic energy of atoms reaching the vane surface is very high. Unstable state continues and nucleation is slow. As a result, the structure is rough, and crystals with different orientations are formed in the columnar structure, and the structure is formed with a non-uniform structure.
[0016]
FIG. 4 shows the results of comparative evaluation of the progress of time series wear under the same conditions for this example and the conventional CrN coating vane. From this result, the conventional CrN coating vane progresses in wear of the vane with the test time, whereas the CrN coated vane of this example shows almost no progress in wear, and the wear resistance of the vane is high. Understand.
[0017]
FIG. 5 shows a sectional structure of the vane according to the first aspect of the present invention. 10 is a vane and 12 is an ion nitride layer processed at 530 ° C. Reference numeral 13 denotes a CrN coating layer formed by ion plating, and the temperature of the vane at the time of the treatment is 530 ° C. which is the same as that of the ion nitriding treatment.
[0018]
FIG. 6 (a) shows the etching cross-sectional structure of the nitride layer of this example. Since the work temperature during ion plating is 530 ° C. which is the same as the nitriding temperature, nitrogen in the nitride layer diffuses. The nitrogen-rich layer on the surface is recognized even after etching. FIG. 6 (b) shows an etching cross-sectional structure of a conventional nitride layer. Since the workpiece temperature during the ion plating process is processed at a temperature equal to or higher than the nitriding temperature, nitrogen in the nitride layer diffuses and etching causes the nitride layer to form. Corroded and discolored black.
[0019]
FIG. 7 shows the results of comparative evaluation of time series wear progress under the same conditions for the present example and the conventional CrN coating vane. From this result, while the conventional CrN coating vane progresses in vane wear with the test time, this example CrN coated vane shows almost no progress in wear and the vane has very high wear resistance. I understand.
[0020]
【The invention's effect】
As described above, according to the first aspect of the present invention, by forming the ion plating skin covering layer processed at a vane temperature of 550 ° C. or less on the surface of the vane, the wear resistance of the vane is always stabilized at a high level. An advantageous effect is obtained.
[0021]
According to the first aspect of the present invention, the ion plating skin covering layer is formed on the nitride layer formed on the surface of the vane base material. By being done below the temperature at which the layers were processed, the wear resistance of the vanes can be stabilized at a higher level.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a rotary compressor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a vane of the rotary compressor according to claim 1. FIG. FIG. 4 is a diagram showing a cross-sectional structure of a vane CrN skin layer of the same rotary compressor. FIG. 4B is a diagram showing a cross-sectional structure of a vane CrN skin layer of a conventional rotary compressor according to claim 1. sectional view of the vane of the rotary compressor described in Figure [5] and which exhibits a wear test results of the vane of the rotary compressor as described in claim 1 6 (a) in claim 1 the described diagram illustrating an etching sectional structure of the vane nitride layer of the same rotary compressor (b) Figure 7 showing the etching cross-sectional structure of the vane nitride layer of a conventional rotary compressor as set forth in claim 1 claim shows the wear test results of the vane of the rotary compressor described in 1 [8] conventional rotary pressure Sectional view of the machine Figure 9 is a cross-sectional view of the vane of the conventional rotary compressor EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric motor part 3 Compressor part 5 Roller 6 Cylinder 7 Shaft 10 Vane 11 Vane CrN coating skin layer 12 Vane ion nitride layer 13 Vane CrN coating skin layer

Claims (1)

The vane having a shaft, a roller attached to the eccentric portion of the shaft, a cylinder that houses the roller, and a vane that is housed in a groove of the cylinder and that has a tip portion that is in sliding contact with the outer periphery of the roller. The ion bombarding process is performed on the nitride layer formed on the surface of the base material, and then a CrN coating layer is formed by the ion plating process. In the ion plating process, the temperature of the vane is 550 ° C. or less. The rotary compressor is made at a temperature equal to or lower than the temperature at which the nitride layer is treated .

Images