KR101128579B1 - A manufacturing process of crank shaft for a rotary compressor - Google Patents

Abstract

The present invention relates to a method for manufacturing a crankshaft of a rotary compressor, the method for manufacturing a long shaft in the form of a pipe made of a steel plate having a sufficient hardness, the shaft is drawn to produce a shaft of a certain standard, the shaft is a product By cutting to length to complete the shaft portion 1a, and forming the crank shaft 1 by forming the crank portion 1 by forming the crank 1b through forging operation by using the shaft portion 1a as a raw material, and sequentially In order to communicate with the flow hole of the shaft portion 1a, the flow hole is drilled into the crank portion with the same diameter, and finally, the crank 1b portion is subjected to turning and processing of various keyways, and the crank 1b of the crank shaft 1b. ) The surface is heat treated to increase the surface hardness and coating to protect the surface of the finished product. The productivity of the crankshaft is improved by the batch process of pipe, drawing and forging. By increasing the crankshaft's rigidity and abrasion resistance by heat-treating the crankshaft under specific conditions, the surface hardness of the crank is improved, and the reliability of the crankshaft is improved. Can be.

Rotary compressor, crankshaft, forging, heat treatment

Description

A manufacturing process of crank shaft for a rotary compressor

1 is a longitudinal sectional view showing a rotary compressor according to the prior art;

2 is a state diagram showing a mechanism part of a rotary compressor according to the prior art;

3 is a perspective view showing a crankshaft of a rotary compressor according to the prior art,

4 is a flow chart showing a manufacturing process of the crankshaft using the casting according to the prior art;

Figure 5 is a flow chart showing a manufacturing process of the crankshaft forged after drawing and drawing steel according to the prior art,

6 is a flowchart illustrating a crankshaft manufacturing process of a rotary compressor according to the present invention.

Explanation of symbols on the main parts of the drawings

1: crankshaft

The present invention relates to a method for manufacturing a crankshaft used in a rotary compressor, and in particular, the crankshaft of an air-conditioning rotary compressor is formed by forging a steel plate, drawn out, forged, and then subjected to heat treatment under specific conditions to improve rigidity and wear resistance of the crankshaft. In addition, the present invention relates to a crankshaft manufacturing method of a rotary compressor capable of improving the reliability and productivity of the rotary compressor.

In general, a compressor is a machine that increases the pressure of a working fluid by receiving power from a power generator such as an electric motor or a turbine and applying a compression work to a working fluid such as air or a refrigerant. Such compressors are widely used in general household appliances such as the air conditioner field and the refrigerator field to the plant industry.

Such compressors are classified into positive displacement compressors and dynamic compressors or turbo compressors according to the compression method. Among them, a volume compressor is widely used in the industrial field, and has a compression method of increasing pressure through volume reduction. The volumetric compressor is further classified into a reciprocating compressor and a rotary compressor.

The reciprocating compressor compresses the working fluid by a linear reciprocating piston inside the cylinder, and has an advantage of producing a high compression efficiency with a relatively simple mechanical element. On the other hand, the reciprocating compressor has a limitation in the rotational speed due to the inertia of the piston, there is a disadvantage that a considerable vibration occurs due to the inertia force.

The rotary compressor compresses the working fluid by a roller revolving in the cylinder eccentrically, and can produce a high compression efficiency at a low speed compared to the reciprocating compressor. Thus, the rotary compressor further has the advantage of less vibration and noise.

Here, the conventional structure of the rotary compressor, as shown in Fig. 1, the stator 104 is a motor mechanism inside the casing 103 is filled with a predetermined amount of oil and provided with the suction pipe 101 and the discharge pipe 102 ) And the rotor 105, and a mechanism part 110 for press-fitting the crankshaft 106 to the center of the rotor 105 and suction-compressing refrigerant gas under the crankshaft 106 is installed. It consists of

As shown in FIG. 2, the mechanism 110 is fixed to the inner circumferential surface of the casing 103 so as to be in close contact with both sides of the circular cylinder 111 and the cranks 111. The shaft 106 consists of a main bearing 112 and a sub bearing 113 which are supported therethrough.

That is, in the case of the rotary compressor 120, the rotation of the motor, which is the driving body, is received through the crankshaft 106 to perform the compression of the mechanism unit 110, and the crankshaft 106 rotates the reciprocating motion. As shown in FIG. 3, the crank 106a is coupled to one end of the connecting rod, and the outer side of the crank 106a has a rotating cylindrical shape and rotates sliding friction. The roller is changed into friction to reduce the resistance of the movement, and the flow hole 106b through which the refrigerant flows is formed in the center of the shaft throughout the entire crankshaft 106.

Conventionally, the crankshaft 106 as described above is entirely manufactured by a casting operation, as shown in FIG. 4, in which a molten metal is cast into a mold and solidified for a predetermined time to be manufactured in the form of a crankshaft 106. In order to make the turning work easier by fixing both ends of the shaft manufactured through this casting process, it is necessary to machine the grooves at both ends of the shaft, and to turn the shaft to lathe, and to the round bar shaft after the turning process. A grinding process for drilling the flow hole 106b in accordance with the inner diameter standard using a gun drill and processing the shaft portion 106c, and a surface for coating to protect the surface of the crankshaft 106 completed through the grinding process. It is manufactured through a coating process.

However, in the above-described method for manufacturing the crankshaft 106, impurities are contained therein and a large number of pores are generated due to the characteristics of the casting, and the wear resistance is degraded, while the wear resistance is degraded, leading to deterioration in quality.

In addition, due to the casting production, drilling and drilling work, turning process takes a lot of time, the productivity is lowered, the cost increase due to the productivity is emerging as a serious problem inevitable.

On the other hand, as another method for manufacturing the crankshaft 106 is a method using forging bar as shown in Figure 5, a long shaft in the form of a pipe through a pipe forming process using a steel plate with a sufficient hardness After shaping, it is manufactured into a shaft having a predetermined standard through a drawing process, and the shaft is cut to fit the length of the product to complete the shaft portion 106c, and the crank 106a is formed by forging work using a round bar or a pipe. The crank portion is completed, and the shaft portion 106c and the crank portion are integrally welded to complete the form of the crank shaft 106, while the crank portion has the same diameter so as to communicate with the flow hole 106b of the shaft portion 106c sequentially. After drilling the flow hole 106b and finally machining the crank 106a portion and processing various keyways, the surface coating is performed to protect the surface of the finished product.

However, when the crankshaft 106 is manufactured by using forging as described above, there is a problem in that the reliability of the product is lowered because of problems in processing accuracy and surface hardness.

Accordingly, the present invention has been made in view of the above-mentioned circumstances, and the rigidity and wear resistance of the crankshaft are improved by pipe forming the crankshaft of the air-conditioning rotary compressor by iron plate, drawing and forging, and performing heat treatment under specific conditions. In addition, the object of the present invention is to provide a method for manufacturing a crankshaft of a rotary compressor that can improve the reliability and productivity of the rotary compressor.

The present invention for achieving the above object is a tube manufacturing process for forming a long shaft in the form of a pipe from a steel plate having a sufficient hardness, and a drawing process for drawing the shaft through the tube manufacturing process to the axis of a certain standard And a cutting step of cutting the shaft in accordance with the product length to complete the shaft portion, a forging step of forming the crank shaft by forming a crank by forging work using the shaft portion as a material, and the shaft portion sequentially. The processing process of drilling the flow hole in the crank part with the same diameter so as to communicate with the flow hole, and finally turning the crank part and processing various key grooves, and heat-treating the crank surface of the crankshaft manufactured by this processing step Heat treatment process to increase hardness and coating treatment to protect surface of finished product It is manufactured through a surface coating process.

In the heat treatment process, the hardness of the surface is maintained at 600 HmV or more through quenching and tempering heat treatment.

In addition, in the heat treatment process, nitriding treatment such as carburization heat treatment and gas nitriding or distillation nitriding is performed to maintain the surface hardness of 600 HmV or more at the surface layer of 0.05 mm and to make the surface hardened layer account for at least 0.001% of the total area. will be.

That is, the crankshaft of the rotary compressor manufactured through the manufacturing process as described above is forged steel to process the shape of the crankshaft, carburizing heat treatment, nitriding treatment or quenching and tempering, etc. to the crank surface of the processed crankshaft surface It is intended to increase the hardness.

Therefore, the productivity of the crankshaft is improved by the collective process of pipe making, drawing and forging, and the heat treatment of the crankshaft of the rotary compressor is performed under specific conditions to improve the rigidity and wear resistance of the crankshaft, and the surface hardness of the crank increases to improve reliability. By replenishing the shortcomings in the conventional crankshaft manufacturing process, the reliability of the rotary compressor can be improved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

6 is a flowchart illustrating a crankshaft manufacturing process of a rotary compressor according to the present invention. The method for manufacturing a crankshaft (1) of a rotary compressor used for air conditioning includes a long shaft in the form of a pipe using an iron plate having sufficient hardness. Molding, drawing the shaft to produce a shaft of a predetermined standard, cutting the shaft to the length of the product to complete the shaft portion (1a), and forming the crank (1b) through a forging operation using the shaft portion (1a) as a material By completing the crank part, the molded part is molded into the shape of the crank shaft 1, while the flow hole is drilled into the crank part with the same diameter so as to communicate with the flow hole of the shaft part 1a, and finally the crank part 1b is turned. And various key grooves, and the like to heat-treat the surface of the crank 1b of the crankshaft 1 to increase surface hardness and to protect the surface of the finished product. To.

Here, the crankshaft (1) manufactured as described above is formed by forming a forging after drawing and forging a steel, the surface of the crankshaft (1) of the formed crankshaft (1) by heat treatment under a specific condition It is characterized by raising the surface hardness of the crankshaft 1 through curing.

In other words, the crankshaft (1) of the rotary compressor is forged steel to process the shape of the crankshaft (1), carburizing heat treatment, nitriding treatment or quenching on the crank (1b) surface of the processed crankshaft (1) and By tempering and the like, the surface hardness is increased.

That is, the crankshaft (1) is a tube forming process for forming a long shaft in the form of a pipe, a drawing process for drawing the shaft passed through the tube forming process to produce a shaft of a predetermined standard, and by cutting the shaft in accordance with the product length shaft portion (1a) ) And a forging step of forming the crankshaft 1 by completing the crank portion formed by forming the crank 1b through the forging operation using the shaft portion 1a as a raw material, and the crankshaft. The crankshaft 1 is completed by forging through a machining process completed in the form of (1), and quenching and tempering heat treatment or surface hardening heat treatment (carburizing and nitriding) on the crank 1b of the crankshaft 1 thus completed. Etc.) to increase the surface hardness.

Therefore, the tubing process is to form a disk cut to fit a predetermined standard in the form of a pipe and then welded to the edge surface, the drawing process is drawn to the longitudinal direction of the long-shape steel pipe through the tubing process for use According to the roughing step, the cutting process is to cut the steel pipe completed through the drawing process to a certain length in accordance with the specifications of the crankshaft (1) to complete the shaft portion (1a), the forging process is constant The crank portion of the round bar or pipe cut to length is locally heated to a constant temperature and then pressurized to form a crank 1b of a desired specification and shape to complete the crank portion.

Then, by coating the surface of the crank (1b) heat treatment is completed as described above to reduce the surface friction by the manganese disulfide it is to be able to protect the surface during operation of the crankshaft (1).

On the other hand, the crankshaft (1) of the rotary compressor to increase the surface hardness by forging the steel and then carburizing heat treatment, nitriding treatment (nitridation treatment such as gas nitriding, carburizing nitriding) or quenching and tempering to the crank (1b) It is made of structure.

In addition, the crank 1b maintains the surface hardness of 600HmV or more through quenching and tempering, and the surface hardening heat treatment of the crank 1b maintains 600HmV or more in the surface layer of 0.05mm after nitriding or immersion nitriding. In contrast to the total area of the crank 1b, the surface hardened layer occupies 0.001% or more.

That is, when the surface layer is 0.05 mm or less, the hardened layer is thin, and after the surface hardened layer of the crank 1b is only slightly worn, the wear of the crank 1b proceeds rapidly and the life of the crank 1b is shorter than the rotary state. This is to make the endurance life similar.

When the hardness is less than 600 HmV, the area of the crank 1b is relatively smaller than the contact area of the rotary, so that the crank 1b is easily worn out, so that the component life is short. When the surface hardened layer is 0.001% or less, the effect of heat treatment is small. .

Here, the heat treatment will be described in more detail as follows.

The gas nitriding is a nitriding treatment, abrasion resistance is high, high temperature hardness, low hardness decrease by reheating, quenching is not necessary.

The crankshaft 1 carries out partial nitriding of the crank 1b part, and washes out the prevention of nitriding parts other than the crank 1b part, that is, the part that does not perform nitriding, and deposits soot in molten iron.

The crank 1b portion is arranged to remove oil from the surface and not to hit each other in the nitriding box, and to inject the ammonia into Ni and Cu steels in the bottom and one row, and then raise the furnace temperature.

The amount of ammonia supplied during nitriding is adjusted so that the exhaust from the furnace contains 20-80% of ammonia and the pressure is 50-80mm. The nitriding treatment is followed by heating to 500-550 ° C. for 20-100 hours in the ammonia stream.                     

The longer the nitriding time is, the deeper the nitride layer becomes, and the higher the nitriding temperature, the lower the maximum hardness and the thicker the nitride layer becomes. Therefore, the hardness of the surface layer at 0.01 mm is 600 HmV or more and the area of nitriding is 0.001% or more of the total area. Airflow temperature and heating time are determined.

The solid carburizing is applied to the carburizing prevention part except the crank part 1b, that is, the part which is not subjected to carburization, to be dried by applying a suspension copper powder acceptor or mixed with clay of iron oxide. The crankshaft 1 is charged into a carburizing box, and the carburizing agent uses charcoal and barium carbonate, sodium carbonate as a promoter, and coke as a diluent. Heat to 850-900 ° C. for 5-8 hours and then cool. Therefore, only the crank 1b portion is carburized.

In liquid carburizing, the part which prevents carburizing is dried by applying a suspension copper powder receiver. Salt, soda ash, barium chloride and the like are added to the bath of the liquid carburizing agent mainly composed of sodium cyanide. This is to prevent oxidation and volatilization of sodium cyanide. The liquid carburizing is heat-treated at a temperature of 80-90 ° C. for 80-100 hours.

On the other hand, the quenching is mounted so that the open inductor over the top surface of the crank (1b) and rotate the crank shaft (1) evenly the entire surface of the crank (1b) to the austenitizing temperature Heat. The heating time is 6-60sec to be 3-5mm quenching depth.

That is, in case of cooling the steel after heating the crankshaft (1) to the austenitizing temperature, the cooling rate in quenching is 120-160deg c / sec when the water temperature is 20 ℃, and 80-140deg c / sec when the temperature is 40 ℃. In case of 10% of the brine, the cooling temperature is 160-200deg c / sec when the liquid temperature is 20 ℃, and the cooling rate is 20-80deg c / sec when the oil temperature is 20 ℃.

Then, the tempering is to charge the quenched crankshaft (1) in the upper furnace and heated to a temperature of 400-600 ℃ and then cooled in a salt bath (saline), oil bath (oil) for 5-16 seconds.

Therefore, by performing a heat treatment to increase the surface hardness of the crank (1b) formed by forging as described above, it is possible to improve the axial rigidity and wear resistance of the crankshaft (1), and the crankshaft (manufactured through only forging in the past) By improving the insufficiency of 1) by heat treatment, the reliability of the product can be improved.

As described above, according to the manufacturing method of the crankshaft of the rotary compressor according to the present invention, the rigidity of the crankshaft is improved by improving the productivity of the crankshaft by a batch process of pipe tube, drawing and forging, and heat-treating the crankshaft of the rotary compressor under specific conditions. And wear resistance is improved, reliability is improved by increasing the surface hardness of the crank, and by improving the reliability of the conventional crankshaft manufacturing process, there is an effect that can improve the reliability of the rotary compressor.

Claims (5)

Pipe forming process for forming a long shaft in the form of a pipe from a steel sheet having a sufficient hardness; And A drawing process of drawing a shaft having undergone the tubing process to produce a shaft having a predetermined standard; and Cutting step of cutting the shaft to the product length to complete the shaft portion; And Forging process for forming the eccentric crank through the forging operation using the shaft portion; And A processing step of drilling a flow hole in the crank portion with the same diameter so as to communicate with the flow hole of the shaft portion in order to form a crank shaft, and finally turning the crank portion and processing various key grooves; and A heat treatment step of increasing the surface hardness by heat-treating the crank surface of the crankshaft manufactured by the processing step; and Through the surface coating process of coating to protect the surface of the finished product; The heat treatment step, Cranking of a rotary compressor characterized in that nitriding treatment such as carburization, gas nitridation, or immersion nitriding is carried out to maintain the surface hardness at 600 HmV or more at 0.05 mm of the surface layer and at least 0.001% of the surface hardened layer relative to the total area. Shaft manufacturing method. delete delete The method of claim 1, wherein the solid carburizing of the carburizing, except for the crank (1b) portion of the carburization prevention is applied by drying the suspension copper powder receiving agent or by mixing the clay of iron oxide, etc., liquid carburization to prevent carburization The part is a crankshaft manufacturing method of a rotary compressor, characterized in that the coating by applying a suspended copper powder receiving agent. 2. The gas nitriding method according to claim 1, wherein the gas nitriding is performed by partial nitriding the crank 1b portion of the crankshaft 1 and washing the non-nitridation portion, i.e., the non-nitridation portion, except for the crank 1b portion and depositing in the molten iron. Crankshaft manufacturing method of a rotary compressor, characterized in that the soot is attached.

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