JPH01148474A - Manufacture of crank shaft - Google Patents

Abstract

PURPOSE:To eliminate the stage working the oil passage of an oblong hole on a crank shaft and to reduce the production cost by joining each axial part by welding to a crank part respectively in case of providing the crank part not co-axial between a pair of axial parts of the coaxial. CONSTITUTION:In case of forming a crank shaft 10 by the main shaft 11 having the through holes 14, 15, 16 whose inner diameters are equal, a crank 12 and sub-shaft 13, a groove 18 is formed at the tip of the main shaft 11 and also the engaging step difference part 19 in which the groove 18 is fitted is provided at one end opening part of the through hole 15 of the crank 12 as well. This main shaft 11 is held by an electrode 20, the crank 12 is held by an electrode 21, the groove 18 is abutted to the engaging step difference part 19 to adjust so that the through holes 14, 15 become co-axial correctly. An AC current is then passed between the electrodes 20, 21, a resistance heat is generated on the groove 18 and step difference part 19 and the groove 18 is pressed in an arrow mark 22 direction to execute welding. The subshaft 13 and crank 12 are similarly subjected to resistance welding as well. The crank shaft 10 is manufactured without working the oil passage of an oblong hole and the production cost can thus be drastically reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a crankshaft used in a rotary compressor.

(Prior Art) Generally, as shown in FIG. 1, a rotary compressor includes a compressor section (2) and an electric motor section (3) housed in a sealed case (1). A crankshaft (4) is provided across the compressor section (2) and the electric motor section (3), and one end of the crankshaft (4) is fitted and fixed to the rotor (5) of the electric motor section (3).

Moreover, the other end of the crankshaft (4) has a crank part (
6) is formed eccentrically, and a roller (8) provided in the cylinder (7) of the compressor part (2) is rotatably fitted into this crank part (6). Therefore, the roller (8) is moved to the cylinder (7) by the crank part (6).
The cylinder (7) is rotated eccentrically within the cylinder (7) to compress the gas supplied into the cylinder (7). Further, a passage (9) is perforated in the crankshaft (4) along its axial direction, and the closed case (1) is passed through the passage (9).
) is adapted to supply the lubricating oil contained in each sliding part, for example, between the crank part (6) and the roller (8).

Conventionally, the crankshaft (4) having the above structure has been made by forging or casting steel. Since the processing accuracy of products made by casting or forging is extremely low, a crankshaft (4) with sufficient precision cannot be obtained unless the product is rough-machined and then finish-machined after the casting or forging process. Ta. Therefore, there was a drawback that not only was the processing time-consuming, but the incidence of defective products was not high. In addition, a passage (9) must be formed in the crankshaft (4) to supply lubricating oil to the sliding parts, but in order to form this passage (9), a long hole must be machined. However, this processing also had the disadvantage of being time-consuming. Furthermore, casting and forging have the disadvantage that it is difficult to reduce their weight.

(Problems to be Solved by the Invention) This invention has a precision that allows direct finishing machining without rough machining, and also eliminates the need to machining passages for lubricating oil. The object of the present invention is to provide a method for producing a lightweight crankshaft.

[Structure of the invention]

(Means and actions for solving the problem) A pair of shaft parts,
When manufacturing a crankshaft consisting of a crank part that is eccentrically arranged between these shaft parts, the crank part and at least one of the pair of shaft parts are connected by welding to reduce manufacturing costs. It is measured by

(Example) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a crankshaft OQ) manufactured by the crankshaft manufacturing method of this embodiment.

This crankshaft 00) has a cylindrical main shaft aυ, a crank α connected to one end of the main shaft aυ,
This crank consists of a subshaft (13) coaxially connected to the main shaft αυ at the end opposite to the main shaft connection side.

The main shaft αυ, the crank α side, and the sub-shaft α level have through holes Q4), (15, αe
are provided, and when connected, form a coaxial communication hole. Furthermore, the axis of the outer peripheral surface αη of the crank α is eccentric with respect to the axes of the main shaft aυ and the sub-shaft a3. The main shaft αυ and the subshaft 0 are made of steel pipes, and the crank α is a forged product, which are connected by resistance welding.

Next, a method for manufacturing the crankshaft of this embodiment will be described.

First, as shown in Fig. M2, there is a groove a at the tip of the main axis αυ.
Form a barrel. On the other hand, an engagement stepped portion α1 into which the groove QFj engages is also provided at one end opening of the through hole α9 at the crank position. Then, the main shaft aυ is held by the electrode (a), and the crank a is held by the electrode Qυ. Then, the electrode (a) is lowered in the direction of the arrow, and the groove α barrel is brought into contact with the retaining step part (19), and the contact is made with a predetermined pressure.At this time, the through holes (14) and (15) Adjust so that they are exactly coaxial. Next, open the switch @,
Mikoku trout, c! An alternating current is passed between υ. Then, resistance heat is generated due to contact resistance and specific resistance between the groove α barrel and the retaining step α■, and this heat increases the temperature of the joint. Then, when the joint reaches the appropriate welding temperature, strong pressure is applied in the direction of arrow Q to complete butt (butt resistance) welding. On the other hand, the subshaft (131) and the crank (
Resistance welding is similarly performed for IJ.

As described above, in this embodiment, the main shaft (1υ) and the subshaft (13) are made of steel pipes, and the crank (121 is a forged product, so the through hole Q4 is already formed), (1
51, (1 [El) is formed, so there is no need to machine long holes that will become oil passages.Moreover, each material has been machined with kana precision in advance, so the finishing cutting process in the subsequent process is unnecessary. can be significantly reduced, making it possible to significantly reduce manufacturing costs.Furthermore, compared to cast products, the elastic modulus is higher, υ, and the rigidity is improved, contributing to improved compression performance.

Note that the embodiment is not limited to the above embodiment, and as shown in FIG. 3, the subshaft member and the crank 01) are integrally formed by forging, and this integrally formed product is resistance welded to the main shaft Oa. Good too. Further, as the welding method, other welding methods other than resistance welding, such as laser welding, may be used.

〔Effect of the invention〕

In the present invention, the crankshaft is obtained by welding a material formed by plastic working in which a through hole is formed in advance, so that a long process for forming an oil passage can be omitted, and a cutting process for finishing can be omitted. By significantly reducing the number of man-hours, manufacturing costs can be significantly reduced. Furthermore, since the elastic modulus can be increased compared to when the material is cast, it can contribute to improving the performance of the compressor to which this crankshaft is applied.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a crankshaft manufacturing method according to one embodiment of the present invention, FIG. 3 is an explanatory diagram of another embodiment of the present invention, and FIG. 4 is an explanatory diagram of a conventional technique. . a@: crankshaft, αυ: main shaft. (L: crank, α3: secondary shaft. Fig. 1 T12 Fig. 3 Confucian 4 Fig.

Claims (4)

[Claims] (1) In a method for manufacturing a crankshaft comprising a pair of coaxial shaft parts and a crank part eccentrically provided between these shaft parts, at least one of the pair of shaft parts is welded to the crank part. A method for manufacturing a crankshaft, characterized by joining. (2) The method for manufacturing a crankshaft according to claim 1, wherein the shaft portion is a tube formed by plastic working. (3) The method for manufacturing a crankshaft according to claim 1, wherein the crank portion is formed by forging and has a hole communicating with the through hole of the shaft portion. (4) The method for manufacturing a crankshaft according to claim 1, wherein the other of the pair of shaft parts is integrally formed with the crank part by forging.