JP3554359B2 - Compressor - Google Patents

Description

[0001]
[Industrial applications]
TECHNICAL FIELD The present invention relates to a compressor used for a refrigerator-refrigerator, an air conditioner, and the like.
[0002]
[Prior art]
In recent years, refrigeration units and air conditioners have been used for refrigerants containing chlorine in a molecule, difluorodichloromethane (hereinafter referred to as CFC-12) or difluorochloromethane (hereinafter referred to as HCFC-), which has been conventionally used due to environmental problems such as destruction of the ozone layer. For example, a change to refrigerants 1, 1, 1, and 2 tetrafluoroethane (hereinafter, referred to as HFC-134a) containing no chlorine in the molecule is being studied. However, the refrigerant that does not contain chlorine in the molecule has poor lubrication performance and needs to improve the characteristics of the sliding material of the compressor.
[0003]
Hereinafter, an example of a conventional compressor will be described with reference to FIG. 1 is a compressor. 2 is a rotor, 3 is a stator, and the rotor 2 and the stator 3 form a motor as a pair. 4 is a shaft, 5 is a bearing, 6 is a connecting rod, 7 is a cylinder, 8 is a piston, and 9 is a piston pin. The shaft 4 press-fitted into the rotor 2 is supported by the bearing 5 and rotated by the motor formed by the rotor 2 and the stator 3. At this time, the rotational motion of the shaft 4 is transmitted through the connecting rod 6 attached to the eccentric portion of the shaft 4 and the piston pin 9 attached to the other end of the connecting rod 6 and fixed to the piston 8, and the piston 8 is moved to the cylinder. 7 reciprocate. Then, in the space 10 formed by the piston 8 and the cylinder 7, the refrigerant gas CFC-12 is sucked and compressed.
[0004]
Conventionally, the piston 8 is formed from cast iron (JIS: FC200), and the cylinder 7 is formed from cast iron (JIS: FC200).
[0005]
In recent years, fiber reinforcement has been used in pistons or cylinders of automobile engines to improve wear resistance while maintaining heat dissipation, which is an advantage of aluminum alloy castings. This fiber reinforced metal (FRM) is a composite material in which the metal matrix is reinforced with fibers of high heat resistance and high strength, such as carbon and ceramics, and has high specific strength and high specific elastic modulus (strength and elastic modulus that cannot be satisfied with conventional materials). Divided by the density). As an actual practical example, for example, there is a piston groove wear ring for a 13B-T diesel engine developed by Toyota Motor Industry in Industrial Materials Vol. 36, No. 12. This is made by using an alumina foam or the like, and casting the above-mentioned fibers around the outer periphery of the piston top which exerts a large heat load. The seizure resistance and abrasion resistance of the ring groove are enhanced to achieve high output. Honda Motor also uses fiber-reinforced metal for the connecting rod, and aims to improve wear resistance while maintaining the advantages of the aluminum alloy base material, such as light weight and heat dissipation.
[0006]
[Problems to be solved by the invention]
However, such a configuration is considered on the premise that the conventional refrigerants CFC-12 and HCFC-22 having high lubrication performance are dissolved in the lubricating oil of the compressor.
[0007]
When using refrigerant HFC-134a, which does not contain chlorine in the molecule and has poor lubrication performance, heat is generated by sliding especially at the contact portion between the piston and the cylinder. The temperature rises and the amount of piston and cylinder wear increases. In the worst case, seizure occurs. Therefore, sufficient durability of the compressor cannot be obtained.
[0008]
From the material side, these problems can be solved if the material of the cylinder or piston itself has excellent heat dissipation, that is, if the thermal conductivity is high, but for example, the cost is low and the heat dissipation is low. An excellent material is an aluminum alloy casting. However, although the aluminum alloy casting has almost the same mechanical strength as cast iron (JIS: FC200), which is a conventional material, it has a problem that adhesive wear occurs due to its low melting point. Therefore, when the refrigerant HFC-134a having poor lubricating performance is used, sufficient wear resistance cannot be ensured only with the aluminum alloy casting, and the durability of the compressor itself cannot be improved.
[0009]
In addition, when fiber-reinforced metal is used, such as in automobile engines, the strength of the fiber-reinforced metal part is reduced due to the fact that the fibers are ubiquitous at the time of metal casting and the directions of the respective fibers with respect to the sliding surface are different. There was a problem that a uniform product could not be obtained.
[0010]
Therefore, it is necessary to optimize the sliding material of the compressor for the above-described refrigerant containing no chlorine and having poor lubricity.
[0011]
The present invention has been made in view of the above problems, and aims at optimizing a sliding material for a compressor using refrigerant HFC-134a to improve the durability of the compressor.
[0012]
[Means for solving the problem]
In order to solve the above problems, a compressor of the present invention has a configuration in which a gas to be compressed is a refrigerant HFC-134a, a piston is formed of cast iron (JIS: FC200), and a cylinder is formed of an aluminum alloy casting. A preform of a ceramic foam having a porosity of 70 to 90% is cast on the sliding inner peripheral surface.
[0013]
In order to solve the above-mentioned problems, a compressor of the present invention has a configuration in which a gas to be compressed is a refrigerant HFC-134a and a piston is formed of cast iron (JIS: FC200). A preform of a foamed metal body of a nickel-chromium alloy having a porosity of 80 to 98% is cast on an inner peripheral surface that slides.
[0014]
In order to solve the above-mentioned problems, a compressor of the present invention has a configuration in which a gas to be compressed is a refrigerant HFC-134a and a piston is formed of cast iron (JIS: FC200). A hollow cylindrical part made of iron is cast on the sliding inner peripheral surface.
[0015]
[Action]
The present invention uses a structure in which a piston is formed of cast iron (JIS: FC200), a cylinder is formed of an aluminum alloy casting, and a preform of a ceramic foam is cast on an inner peripheral surface sliding with the piston. By doing so, the mechanical strength of the cylinder is uniformly improved while the heat radiation property equivalent to that of an aluminum alloy casting is ensured, and the amount of wear at the contact portion between the piston and the cylinder is reduced. As a result, the durability of the compressor is improved.
[0016]
Further, in a configuration in which the piston is formed of cast iron (JIS: FC200), a cylinder is formed of an aluminum alloy casting, and a metal foam of a nickel-chromium alloy having a porosity of 80 to 98% is formed on an inner peripheral surface sliding with the piston. By using a cast product of the above preform, the hardness of the cylinder is uniformly improved while the heat radiation property of an aluminum alloy casting is secured, and the amount of wear at the contact portion between the piston and the cylinder is reduced. As a result, the durability of the compressor is improved.
[0017]
Further, in a configuration in which the piston is formed of cast iron (JIS: FC200), a cylinder is formed of an aluminum alloy casting, and a hollow cylindrical component made of iron is cast on an inner peripheral surface that slides with the piston. Thereby, the melting point of the cylinder is maintained at the same level as that of the conventional cast iron (JIS: FC200), and the amount of wear at the contact portion between the piston and the cylinder is reduced, while ensuring the heat radiation property of the aluminum alloy casting. As a result, the durability of the compressor is improved.
[0018]
【Example】
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 shows a sectional view of the compressor of the present invention. 1 is a compressor. 2 is a rotor, 3 is a stator, and the rotor 2 and the stator 3 form a motor as a pair. 4 is a shaft, 11 is a bearing, 6 is a connecting rod, 7 is a cylinder, 8 is a piston, and 9 is a piston pin. The shaft 4 press-fitted into the rotor 2 is supported by the bearing 5 and rotated by the motor formed by the rotor 2 and the stator 3. At this time, the rotational motion of the shaft 4 is transmitted through the connecting rod 6 attached to the eccentric portion of the shaft 4 and the piston pin 9 attached to the other end of the connecting rod 6 and fixed to the piston 8, and the piston 8 is moved to the cylinder. 7 reciprocate. Then, in the space 10 formed by the piston 8 and the cylinder 7, the refrigerant gas CFC-12 is sucked and compressed.
[0020]
Here, FIG. 2 shows an enlarged sectional view of the cylinder 11 of the present embodiment. FIG. 3 is an enlarged cross-sectional view of the inner peripheral surface composite layer 11a taken along the line AA ′ of the present embodiment. The cylinder base 11b is made of an aluminum alloy, and constitutes most of the cylinder 11. The cylinder 11 forms an alumina foam preform 11c having a wire diameter of 3 μm and a length of 500 μm, and impregnates the aluminum alloy 11d by casting to form a composite. This inner peripheral surface composite layer contains 10% by volume of an alumina foam.
[0021]
Here, the thermal conductivity of alumina is about 1/5 to 1/3 of that of an aluminum alloy casting, but in this embodiment, a preform of an alumina foam having a porosity of 90% is placed near the inner peripheral surface. Since it is applied only to the aluminum alloy casting, it can be said that the thermal conductivity is almost the same as that of the aluminum alloy casting. As a result, the thermal conductivity can be as high as that of an aluminum alloy casting, and is two to three times the thermal conductivity of the conventional cast iron (JIS: FC200), and the heat dissipation is improved.
[0022]
In addition, by using an alumina foam having high rigidity and high-temperature strength near the inner peripheral surface of the cylinder, the strength does not decrease to near the melting point of the base material (about 600 ° C.), so that adhesive wear can be prevented. . Moreover, the fatigue strength is about 4 to 5 × 10 ² , which is 10 times or more as compared with that of the conventional material, cast iron (JIS: FC200), so that the long-term durability of the cylinder can be maintained.
[0023]
As described above, in the present embodiment, in the configuration in which the gas to be compressed is HFC-134a and the piston 8 of the actual compressor is formed of cast iron (JIS: FC200), the cylinder 11 is made of an alumina foam preform. By using an aluminum alloy casting into which the aluminum alloy is cast, heat dissipation can be maintained at the same level as the aluminum alloy casting, wear of the cylinder and the piston can be prevented, and the durability of the compressor can be improved.
[0024]
Although the preform of the alumina foam having a porosity of 90% is used according to this embodiment, the same effect can be obtained even if the porosity is 70 to 90%.
[0025]
Further, according to this embodiment, the inner peripheral surface composite layer is made of an alumina foam, but the same effect can be obtained by using a silicon carbide foam or an alumina / silica foam.
[0026]
Further, according to the present embodiment, after forming the preform 11c of the alumina foam, the aluminum alloy 11d is impregnated by casting to form a composite. However, the same effect can be obtained by using the die casting method.
[0027]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
[0028]
FIG. 4 shows a sectional view of the compressor of the present invention.
Here, FIG. 5 shows an enlarged sectional view of the cylinder 12 of the present embodiment. FIG. 6 is an enlarged cross-sectional view of the inner peripheral surface composite layer taken along line AA ′ of the present embodiment. The cylinder base 12b is made of an aluminum alloy as a raw material, and constitutes most of the cylinder 12. The cylinder 12 forms a metal foam preform 12c containing 35% by weight of chromium and having a porosity of 82% of a nickel-chromium alloy, and impregnated with an aluminum alloy 12d to form a composite.
[0029]
Here, the thermal conductivity of the nickel-chromium alloy is about 1/2 to 2/3 of that of the aluminum alloy casting, but in this embodiment, the metal foam having a porosity of 82% is placed only near the inner peripheral surface. Therefore, it can be said that the thermal conductivity is substantially equal to that of the aluminum alloy casting. As a result, the thermal conductivity can be as high as that of an aluminum alloy casting, and is about two to three times the thermal conductivity of the conventional cast iron (JIS: FC200), and the heat dissipation is improved.
[0030]
Further, the hardness in the vicinity of the inner peripheral surface of the cylinder is HV200 to 400, which is about twice as large as that of the conventional cast iron (JIS: FC200), and the wear resistance is improved. As the hardness increases, the compressive strength also increases, so that it can be used for a high-output compressor.
[0031]
As described above, in the present embodiment, in the configuration in which the compressed gas is HFC-134a and the piston 8 of the actual compressor is formed of cast iron (JIS: FC200), the cylinder 12 is made of metal foam of nickel-chromium alloy. By using an aluminum alloy casting in which a body is cast, heat dissipation can be as high as that of an aluminum alloy casting, wear of cylinders and pistons can be prevented, and durability of the compressor can be improved.
[0032]
According to the present embodiment, the nickel chromium alloy metal foam 12c is molded and then impregnated with the aluminum alloy 12d to form a composite. However, the same effect can be obtained by using the die casting method. .
[0033]
According to this embodiment, the same effect can be obtained even if the porosity of the nickel-chromium alloy metal foam is 80 to 98%.
[0034]
The nickel-chromium alloy in this embodiment contains 35% by weight of chromium, but the same effect can be obtained with a nickel-chromium alloy containing 25 to 45% of chromium.
[0035]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Note that the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
[0036]
FIG. 7 shows a sectional view of the compressor of the present invention.
Here, FIG. 8 shows an enlarged vertical sectional view of the cylinder 13 of this embodiment. The cylinder base 13 b is made of an aluminum alloy as a raw material and constitutes most of the cylinder 13. The cylinder 13 is formed by molding a hollow cylindrical 13a made of cast iron (JIS: FC200), and joining an aluminum alloy by casting.
[0037]
Here, since the thermal conductivity of the cast iron (JIS: FC200) is about 1/3 to 1/2 compared to the aluminum alloy casting, in this embodiment, the cast iron (JIS: FC200) is placed only near the inner peripheral surface. Therefore, it can be said that the thermal conductivity is substantially equal to that of the aluminum alloy casting. As a result, the thermal conductivity can be as high as that of an aluminum alloy casting, and is about two to three times the thermal conductivity of the conventional cast iron (JIS: FC200), and the heat dissipation is improved.
[0038]
Further, by using a cast iron (JIS: FC200) in the vicinity of the inner peripheral surface, the inner peripheral surface, that is, the sliding surface has a melting point (1420 to 1550 ° C.) without lowering the melting point (140 to 1550 ° C.). To a high degree and adhesive wear is suppressed.
[0039]
As described above, in the present embodiment, a hollow cylindrical cast iron (JIS) is used for the cylinder 13 in a configuration in which the compressed gas is HFC-134a and the piston 8 of the actual compressor is formed of cast iron (JIS: FC200). : FC200), the use of an aluminum alloy casting can ensure the same heat dissipation as an aluminum alloy, prevent cylinder and piston wear, and improve the durability of the compressor. .
[0040]
In this embodiment, the cost is relatively low, and in addition to the above-described casting method, a cylinder is formed by a die casting method or a method of press-fitting a hollow cylindrical cast iron 13a and an aluminum alloy casting 13b and shrink-fitting. A similar effect can be obtained.
[0041]
Further, according to the present embodiment, the hollow cylindrical component is formed from cast iron (JIS: FC200), but the same effect can be obtained by using an iron material having a melting point higher than that of an aluminum alloy casting.
[0042]
【The invention's effect】
As described above, according to the present invention, the cylinder is formed from an aluminum alloy casting, and a preform of a ceramic foam having a porosity of 70 to 90% is cast on the inner peripheral side of the cylinder, whereby the aluminum is cast. Uniformly improved mechanical strength while maintaining heat dissipation comparable to alloy castings, improved piston and cylinder sliding conditions even under severe conditions using refrigerant HFC134a, and as a result, improved compressor durability can do.
[0043]
Further, by using a cylinder formed of an aluminum alloy casting and casting a metal foam of a nickel-chromium alloy having a porosity of 80 to 98% on the inner peripheral side thereof, the heat radiation property of the aluminum alloy casting can be improved. While maintaining the hardness, the hardness is uniformly improved, and the sliding state between the piston and the cylinder can be improved even under severe conditions using the refrigerant HFC134a, and as a result, the durability of the compressor can be improved.
[0044]
In addition, the cylinder is made of an aluminum alloy casting, and the inner peripheral side of the cylinder is cast with a hollow cylindrical part made of iron. Even under severe conditions using the refrigerant HFC134a, the sliding state between the piston and the cylinder can be improved, and as a result, the durability of the compressor can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view of a compressor using a first embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view of a cylinder in the first embodiment of the present invention. FIG. 3 is a first embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of the inner peripheral composite layer taken along line AA ′ in the example. FIG. 4 is a cross-sectional view of a compressor using the second embodiment of the present invention. FIG. 5 is a second embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the inner peripheral surface composite layer taken along the line AA ′ in the second embodiment of the present invention. FIG. 7 is a diagram showing a third embodiment of the present invention. FIG. 8 is an enlarged longitudinal sectional view of a cylinder in a third embodiment of the present invention. FIG. 9 is a sectional view of a conventional compressor.
8 piston 7 cylinder

Claims (3)

The gas to be compressed is refrigerant 1, 1, 1, 2 tetrafluoroethane, and a shaft connected to the electric motor, a bearing at one end thereof is attached to a connecting rod attached to the shaft, and a multi-end bearing of the connecting rod is attached to the shaft. A piston pin, a piston fixed to the piston pin, and a component of a compressor including a cylinder that forms a compression chamber integrally with the piston, wherein the cylinder is formed of an aluminum alloy casting, and the piston is formed. A compressor formed by casting iron and casting a preform of a ceramic foam having a porosity of 70 to 90% on an inner peripheral surface sliding with the piston. The gas to be compressed is refrigerant 1, 1, 1, 2 tetrafluoroethane, and a shaft connected to the electric motor, a bearing at one end thereof is attached to a connecting rod attached to the shaft, and a multi-end bearing of the connecting rod is attached to the shaft. A piston pin, a piston fixed to the piston pin, and a component of a compressor including a cylinder that forms a compression chamber integrally with the piston, wherein the cylinder is formed of an aluminum alloy casting, and the piston is formed. A compressor characterized in that a metal foam of a nickel-chromium alloy having a porosity of 80 to 98% is cast on an inner peripheral surface formed of cast iron and sliding with the piston. The gas to be compressed is refrigerant 1, 1, 1, 2 tetrafluoroethane, and a shaft connected to the electric motor, a bearing at one end thereof is attached to a connecting rod attached to the shaft, and a multi-end bearing of the connecting rod is attached to the shaft. A piston pin, a piston fixed to the piston pin, and a component of a compressor including a cylinder that forms a compression chamber integrally with the piston, wherein the cylinder is formed of an aluminum alloy casting, and the piston is formed. A compressor formed of cast iron and having a hollow cylindrical part made of iron cast on an inner peripheral surface sliding with the piston.

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