JP5760608B2 - Crankshaft manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a crankshaft for a compressor or the like used in, for example, an air conditioner or a refrigerator.

  Conventionally, as a method of manufacturing a crankshaft, there has been a method in which the front shaft and the rear shaft of the crankshaft are subjected to quenching treatment to increase hardness and improve wear resistance (Japanese Patent Laid-Open No. 2008-38787). Gazette: see Patent Document 1).

JP 2008-38787 A

  However, in the above conventional crankshaft manufacturing method, the two eccentric portions arranged between the front shaft and the rear shaft of the crankshaft are not quenched, and the resistance of the eccentric portions is not affected. Abrasion was not improved.

  Therefore, in order to improve the wear resistance of the eccentric portion by performing quenching treatment on the eccentric portion of the crankshaft, generally, quenching treatment is performed on the two eccentric portions as shown in FIG. (Step S101), the front shaft and the rear shaft are finished by polishing (Step S102), and then one eccentric portion is finished by polishing (Step S103), and then the other eccentric portion is removed. A finishing process is performed by polishing (step S104).

  Here, as shown in FIG. 6, the crankshaft 100 includes a front shaft 101, a first eccentric portion 103, a connecting shaft portion 105, a second eccentric portion 104, which are sequentially arranged along the axial direction. When the crankshaft 100 is subjected to a quenching process, the ease of heat escape is different between the eccentric side and the anti-eccentric side in each of the first and second eccentric portions 103 and 104. As a result, an imbalance occurs in the quenching depth.

  More specifically, when the quenching process is performed on the first eccentric portion 103, the shaft portion 101 is located in the vicinity of the corner portion (A1 portion in the figure) on the eccentric side of the first eccentric portion 103. , 105 does not exist, the heat of quenching does not escape to the shaft portions 101, 105. For this reason, the hardened layer 103a (shown by hatching) generated by quenching becomes deeper at the corners at the corners on the eccentric side. On the other hand, since the shaft portions 101 and 105 exist in the vicinity of the corner portion (A2 portion in the drawing) of the first eccentric portion 103 on the side opposite to the eccentric portion, Escape to 105. For this reason, the hardened layer 103a generated by quenching becomes shallow at the corner portion on the opposite eccentric side.

  Similarly, when quenching the second eccentric portion 104, the shaft portions 102 and 105 are located in the vicinity of the corner portion (B1 portion in the drawing) of the second eccentric portion 104 near the corner portion. Since it does not exist, the heat of quenching does not escape to the shaft portions 102 and 105. For this reason, the hardened layer 104a (shown by hatching) generated by quenching becomes deeper at the corners at the corners on the eccentric side. On the other hand, in the corner portion (B2 portion in the drawing) of the second eccentric portion 104 on the side opposite to the eccentric portion, there are shaft portions 102 and 105 in the vicinity of the corner portion. Escape to 105. For this reason, the hardened layer 104a generated by quenching becomes shallow at the corner portion on the opposite eccentric side.

  Then, when the first and second eccentric portions 103 and 104 are finished by the procedure shown in FIG. 5, residual stress due to quenching occurs in the first and second eccentric portions 103 and 104 in an unbalanced manner, The first and second eccentric parts 103 and 104 are bent, causing a problem that the rear shaft 102 swings with respect to the front shaft 101 as indicated by the shaft center 100a of the crankshaft 100. When the rear shaft 102 swings, the bearing comes into line contact and the reliability decreases. The inventor of the present application has newly found the phenomenon of the shake of the rear shaft 102.

  Accordingly, an object of the present invention is to provide a method of manufacturing a crankshaft in which the rear shaft does not run out relative to the front shaft when heat treatment is performed on a plurality of eccentric portions of the crankshaft to improve wear resistance.

In order to solve the above-mentioned problem, a manufacturing method of a crankshaft of the present invention includes
A front shaft and a rear shaft disposed concentrically to each other, have a plurality of eccentric portions which are disposed between the front shaft and the rear shaft, the front shaft and said rear shaft and the plurality of eccentric portions Is a manufacturing method of a crankshaft formed integrally ,
A step of subjecting only the plurality of eccentric portions to surface modification treatment;
Polishing at least the front shaft;
Polishing the plurality of eccentric portions in order from the front shaft side to the rear shaft side;
And a step of polishing the rear shaft in order.

According to the crankshaft manufacturing method of the present invention, after the surface modification treatment is performed only on the plurality of eccentric portions, the step of polishing at least the front shaft, and the plurality of eccentric portions are arranged on the front shaft side. In order to improve the wear resistance of the eccentric portion by the surface modification process, the surface modification process is performed in order from the process of polishing to the rear shaft side in order and the process of polishing the rear shaft. It is possible to cancel the distortion generated by releasing the residual stress due to the above, and to manufacture a crankshaft in which the rear shaft does not run out of the front shaft.

In the crankshaft manufacturing method of one embodiment,
Applying a surface modification treatment to the plurality of eccentric parts;
Polishing only the front shaft,
Polishing the plurality of eccentric portions in order from the front shaft side to the rear shaft side;
A process of polishing the rear shaft is sequentially performed.

  According to the crankshaft manufacturing method of this embodiment, after the surface modification treatment is performed on the plurality of eccentric portions, the step of polishing only the front shaft, and the plurality of eccentric portions are arranged on the front shaft side. From the front shaft to the rear shaft side, the polishing process and the rear shaft polishing process are sequentially performed. Distortion caused by opening can be canceled.

  Therefore, when the wear resistance of the eccentric portion is improved by the surface modification treatment, a crankshaft without the rear shaft swinging with respect to the front shaft can be manufactured.

  In the crankshaft manufacturing method of one embodiment, the surface modification treatment is any one of induction hardening, nitriding, carburizing and quenching, or carbonitriding and quenching.

  In the crankshaft manufacturing method of one embodiment, the material of the crankshaft is any one of gray cast iron, spheroidal graphite cast iron, carbon steel, or alloy steel.

In the crankshaft manufacturing method of one embodiment,
Applying a surface modification treatment to the plurality of eccentric parts;
Polishing the front shaft and the rear shaft at the same time;
Polishing the plurality of eccentric portions in order from the front shaft side to the rear shaft side;
A process of polishing the rear shaft again is sequentially performed.

  According to the crankshaft manufacturing method of this embodiment, after the surface modification treatment is performed on the plurality of eccentric portions, the step of simultaneously polishing the front shaft and the rear shaft, and the plurality of eccentric portions The polishing process is sequentially performed from the front shaft side to the rear shaft side, and the rear shaft polishing process is performed again. Distortion caused by stress release can be canceled. In addition, when the front shaft and the rear shaft are simultaneously processed as the first finishing process, the machining time for the final finishing of the rear shaft can be shortened by leaving a rear shaft allowance of about 20 to 60 μm, for example.

  Therefore, when the wear resistance of the eccentric portion is improved by the surface modification treatment, a crankshaft free from runout of the rear shaft relative to the front shaft can be manufactured.

  According to the crankshaft manufacturing method of the present invention, after the surface modification treatment is performed on the plurality of eccentric portions, at least the step of polishing the front shaft, and the plurality of eccentric portions from the front shaft side. Since the polishing process and the polishing process of the rear shaft are sequentially performed on the rear shaft side, when the wear resistance of the eccentric portion is improved by the surface modification process, A crankshaft with no rear shaft runout can be manufactured.

It is sectional drawing which shows one Embodiment of the compressor of this invention. It is a flowchart which shows 1st Embodiment of the manufacturing method of the crankshaft of this invention. It is an enlarged view of a crankshaft. It is a flowchart which shows 2nd Embodiment of the manufacturing method of the crankshaft of this invention. It is a flowchart which shows the manufacturing method of the conventional crankshaft. It is an enlarged view of a crankshaft.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a sectional view showing a first embodiment of a compressor according to the present invention. The compressor includes a hermetic container 1, a motor 3 disposed in the hermetic container 1, and a first compression element 2 </ b> A and a second compression element 2 </ b> B that are disposed in the hermetic container 1 and arranged in the order close to the motor 3. And a crankshaft 12 that connects the motor 3 to the first compression element 2A and the second compression element 2B.

  The compressor is a high-pressure dome type rotary compressor, in which the compression elements 2A and 2B are disposed below and the motor 3 is disposed above. Gaseous high-pressure fluid is discharged from the compression elements 2A and 2B. The high-pressure fluid fills the inside of the sealed container 1, cools the motor 3, and is then discharged from the discharge pipe 13 to the outside of the sealed container 1.

  The compressor constitutes a refrigerant circuit together with a condenser, an expansion mechanism and an evaporator (not shown). The fluid such as the refrigerant compressed by the compressor flows in order through the condenser, the expansion mechanism, and the evaporator, and returns to the compressor.

  The motor 3 includes a rotor 6 and a stator 5 disposed on the outer side in the radial direction of the rotor 6 via an air gap. A crankshaft 12 is attached to the rotor 6.

  The rotor 6 includes, for example, a rotor core made of laminated electromagnetic steel plates and a magnet embedded in the rotor core. The stator 5 has a stator core made of, for example, iron and a coil wound around the stator core.

  The motor 3 causes the rotor 6 to rotate together with the crankshaft 12 by electromagnetic force generated in the stator 5 by passing an electric current through the coil, and drives the compression elements 2A and 2B via the crankshaft 12.

  The crankshaft 12 is made of, for example, any one of gray cast iron, spheroidal graphite cast iron, carbon steel, and alloy steel. The crankshaft 12 includes a front shaft 140 and a rear shaft 240 that are arranged concentrically with each other, and a first eccentric portion 126 and a second eccentric portion 226 that are arranged in series between the front shaft 140 and the rear shaft 240. Have

  The front shaft 140, the first eccentric portion 126, the second eccentric portion 226, and the rear shaft 240 are sequentially arranged from the motor 3 side. The first eccentric portion 126 is disposed in the first compression element 2A. The 2nd eccentric part 226 is arrange | positioned in the 2nd compression element 2B. The first eccentric part 126 and the second eccentric part 226 are connected by a connecting shaft 340.

  The first compression element 2A is disposed above the second compression element 2B. The first compression element 2 </ b> A includes a first cylinder 121 and a first roller 127 disposed in the first cylinder 121.

  The first cylinder 121 is sandwiched between the upper end plate member 50 and the intermediate end plate member 70 to form a first cylinder chamber 122. A first pipe 111 connected to an accumulator (not shown) is connected to the first cylinder 121.

  The first roller 127 is fitted in the first eccentric portion 126 of the crankshaft 12 disposed in the first cylinder chamber 122. The first roller 127 is disposed in the first cylinder chamber 122 so as to be able to revolve, and eccentrically rotates in the first cylinder 121 to perform a compression action. The fluid compressed in the first cylinder chamber 122 is discharged to the outside of the first cylinder chamber 122 through the muffler.

  The second compression element 2 </ b> B has a second cylinder 221 and a second roller 227 disposed in the second cylinder 221.

  The second cylinder 221 is sandwiched between the intermediate end plate member 70 and the lower end plate member 60 to form a second cylinder chamber 222. A second pipe 211 connected to an accumulator (not shown) is connected to the second cylinder 221.

  The second roller 227 is fitted to the second eccentric portion 226 of the crankshaft 12 disposed in the second cylinder chamber 222. The second roller 227 is disposed in the second cylinder chamber 222 so as to be able to revolve, and eccentrically rotates in the second cylinder 221 to perform a compression action. The fluid compressed in the second cylinder chamber 222 is discharged to the outside of the second cylinder chamber 222 through the muffler.

  Next, a method for manufacturing the crankshaft 12 will be described.

  As shown in FIG. 2, first, the first and second eccentric portions 126 and 226 are subjected to high-frequency quenching (step S11). Then, after polishing only the front shaft 140 (step S12), the first eccentric portion 126 is polished (step S13), and then the second eccentric portion 226 is polished (step S14). Then, the rear shaft 240 is polished (step S15).

  Here, as shown in FIG. 3, when the crankshaft 12 is quenched, heat is easily escaped on the eccentric side and the anti-eccentric side in each of the first and second eccentric portions 126 and 226. Is different, the imbalance occurs in the quenching depth.

  More specifically, when quenching the first eccentric portion 126, a corner 140 on the eccentric side of the first eccentric portion 126 (portion A1 in the figure) has a shaft 140, Since 340 does not exist, the heat of quenching does not escape to the shafts 140 and 340. For this reason, the hardened layer 126a (shown by hatching) generated by quenching is deepened at the corners on the eccentric side. On the other hand, since the shafts 140 and 340 exist in the vicinity of the corner portion (A2 portion in the drawing) of the first eccentric portion 126 on the opposite eccentric side, the heat of quenching is transferred to the shafts 140 and 340. escape. For this reason, the hardened layer 126a generated by quenching becomes shallow at the corner portion on the opposite eccentric side.

  Similarly, when quenching the second eccentric portion 226, the shafts 240 and 340 are present in the vicinity of the corner portion on the eccentric side of the second eccentric portion 226 (B1 portion in the figure). Therefore, the heat of quenching does not escape to the shafts 240 and 340. Therefore, the hardened layer 226a (shown by hatching) generated by quenching is deepened at the corners on the eccentric side. On the other hand, since the shafts 240 and 340 are present in the vicinity of the corner portion on the opposite eccentric side of the second eccentric portion 226 (B2 portion in the figure), the heat of quenching is transferred to the shafts 240 and 340. escape. For this reason, the hardened layer 226a generated by quenching becomes shallow at the corner portion on the opposite eccentric side.

  In the crankshaft 12 manufacturing method, after the first and second eccentric portions 126 and 226 are quenched, the front shaft 140, the first eccentric portion 126, the second eccentric portion 226, and the rear shaft 240 are moved. Since the polishing process is performed sequentially, the finishing process is performed in order from the front shaft 140 that is easy to use as a processing standard. For this reason, the distortion which generate | occur | produces by the residual stress release by hardening processing can be canceled.

  Therefore, when the wear resistance of the eccentric portions 126 and 226 is improved by the quenching process, the crankshaft 12 in which the rear shaft 240 does not shake with respect to the front shaft 140 can be manufactured. That is, the axis 12a of the crankshaft 12 can be made without bending.

  In addition to the induction hardening process, the eccentric parts 126 and 226 are subjected to a surface modification process such as a nitriding process, a carburizing and quenching process, or a carbonitriding and quenching process, thereby improving the resistance of the eccentric parts 126 and 226. Even when the wearability is improved, an unbalance occurs in the depth of surface modification between the eccentric side and the anti-eccentric side of the eccentric parts 126 and 226. However, depending on the manufacturing method of the crankshaft 12, the crankshaft 12 The shaft center 12a can be made without bending. Further, in the quenching process, it is usual to perform tempering after quenching, but the method of manufacturing the crankshaft 12 has the same effect even when only quenching is performed without tempering. It goes without saying that it is obtained.

  In addition, when the crankshaft has three or more eccentric portions, the plurality of eccentric portions are polished in order from the front shaft side to the rear shaft side in step S13 and step S14 in FIG. The axis can be made unbent.

(Second Embodiment)
FIG. 4 shows a second embodiment of the crankshaft manufacturing method of the present invention. The method for manufacturing the crankshaft will be described. As shown in FIG. 4, first, the first and second eccentric parts 126 and 226 are subjected to a high-frequency quenching process (step S21).

  Then, after polishing the front shaft 140 and the rear shaft 240 simultaneously (step S22), the first eccentric portion 126 is polished (step S23), and then the second eccentric portion 226 is polished (step). S24) Finally, the rear shaft 240 is polished again (step S25). Note that the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and thus description thereof is omitted.

  According to the crankshaft manufacturing method, the rear shaft 240 is ground again, so that distortion generated by releasing residual stress due to quenching can be canceled. Further, when the front shaft 140 and the rear shaft 240 are simultaneously processed as the first finishing process, the machining time for the final finishing of the rear shaft 240 is shortened by leaving the machining allowance of the rear shaft 240 by about 20 to 60 μm, for example. it can.

  Therefore, when the wear resistance of the eccentric portions 126 and 226 is improved by the quenching process, the crankshaft 12 in which the rear shaft 240 does not shake with respect to the front shaft 140 can be manufactured. Further, in the grinding process of the crankshaft 12, the accuracy of the center hole between the front shaft 140 and the rear shaft 240 becomes unnecessary.

  When the crankshaft has three or more eccentric portions, the plurality of eccentric portions are polished in order from the front shaft side to the rear shaft side in step S23 and step S24 in FIG. The axis can be made unbent.

  Further, similarly to the first embodiment, the eccentric portion is subjected to the surface modification treatment such as nitriding treatment, carburizing quenching treatment, carbonitriding quenching treatment, etc. in addition to the induction hardening treatment. The crankshaft manufacturing method allows the crankshaft axis to be free of bending.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the feature points of the first and second embodiments may be variously combined.

  In the crankshaft manufacturing method of the present invention, after the surface modification treatment is performed on the plurality of eccentric portions, the rear shaft is polished so as to cancel the distortion caused by releasing the residual stress due to the surface modification treatment. In the case where the wear resistance of the eccentric portion is improved by the surface modification process, a crankshaft having no runout of the rear shaft relative to the front shaft can be manufactured.

DESCRIPTION OF SYMBOLS 1 Airtight container 2A 1st compression element 2B 2nd compression element 3 Motor 5 Stator 6 Rotor 12 Crankshaft 12a Axis center 121 1st cylinder 126 1st eccentric part 127 1st roller 140 Front shaft 221 2nd cylinder 226 2nd eccentric part 227 Second roller 240 Rear shaft 340 Connecting shaft

Claims (5)

A front shaft (140) and a rear shaft (240) disposed concentrically with each other, and a plurality of eccentric portions (126, 226) disposed between the front shaft (140) and the rear shaft (240). Yes, and the front shaft (140), said rear shaft (240), the plurality of eccentric portions (126, 226) and is a method for producing a crankshaft integrally formed with (12),
A step of subjecting only the plurality of eccentric portions (126, 226) to surface modification;
Polishing at least the front shaft (140);
Polishing the plurality of eccentric portions (126, 226) in order from the front shaft (140) side to the rear shaft (240) side;
A method of manufacturing a crankshaft, comprising sequentially performing a step of polishing the rear shaft (240). In the manufacturing method of the crankshaft of Claim 1,
A step of subjecting the plurality of eccentric portions (126, 226) to a surface modification treatment;
Polishing only the front shaft (140);
Polishing the plurality of eccentric portions (126, 226) in order from the front shaft (140) side to the rear shaft (240) side;
A method of manufacturing a crankshaft, comprising sequentially performing a step of polishing the rear shaft (240). In the manufacturing method of the crankshaft of Claim 1 or 2,
The method for producing a crankshaft, wherein the surface modification treatment is any one of induction hardening, nitriding, carburizing and quenching, or carbonitriding and quenching. In the manufacturing method of the crankshaft as described in any one of Claim 1 to 3,
The crankshaft (12) is made of any one of gray cast iron, spheroidal graphite cast iron, carbon steel, and alloy steel. In the manufacturing method of the crankshaft of Claim 1,
A step of subjecting the plurality of eccentric portions (126, 226) to a surface modification treatment;
Polishing the front shaft (140) and the rear shaft (240) simultaneously;
Polishing the plurality of eccentric portions (126, 226) in order from the front shaft (140) side to the rear shaft (240) side;
A method of manufacturing a crankshaft, comprising sequentially performing a step of polishing the rear shaft (240) again.

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