JPS61157871A - Cam shaft - Google Patents

Abstract

PURPOSE:To produce a cam shaft which is lubricated enough with oil and has excellent shock resistant property by carrying out diffusion joining of a hollow shaft made of dissolved material to a cam composed of a sintered body fitted on the shaft. CONSTITUTION:A cam shaft is formed of a shaft 21 made of metallic tube and a cam 22 composed of a sintered body fitted eccentrically on the shaft 21, and the shaft 21 is firmly fixed to the cam 22 by diffusion joining. In the case of the cam shaft composed as described above, since lubricating oil flowed into a casing 4 also flows through the inside of the cam 22, it can flow effectively in the inside of the casing 4. In addition, as the shaft 21 is treated by case hardening method, its wear caused by revolution can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a camshaft used for driving a rotor in, for example, a four-tary compressor.

[Technical background of the invention and its problems]

In rotary compressors used in air conditioning equipment, etc., a camshaft equipped with an eccentric cam is used to rotate a rotor installed in a casing. Oil lubrication is applied between the two to prevent wear.

Conventionally, this camshaft was made of cast iron.
A cast product is used that integrates the head and cam. However, when this cast camshaft is used, a problem arises in that the effect of oil lubrication on the camshaft cannot be fully utilized.

1 and 2 show a rotary compressor using a conventional camshaft. The camshaft is formed of a cast product in which a shaft 1 and a cam 2 eccentric to the shaft 1 are integrally cast, and the shaft 2 has an oil hole 3 formed in the axial direction through which lubricating oil passes. be. The shaft 1 is connected to a motor (not shown) and supported by a bearing 5 provided in a casing 4 constituting a compression chamber, and a rotor 6 provided in the casing 4 is rotatably fitted to the cam 3. be done. In addition, in the figure, 2 is a partition vane, 8 is a suction port,
9 is a discharge port. Then, as the shaft 1 is rotated by the motor and the cam 2 rotates together, the rotor 6 rotates inside the casing 4, so gas is sucked into the inside of the casing 5 via the suction tube 8 and compressed. After that, it is discharged from the discharge port 9. Further, in order to lubricate the camshaft, an oil reservoir 12 for storing lubricating oil J1 is provided inside the outer case 10 housing the rotary compressor. The lubricating oil 11 is passed from the oil reservoir 12 to the oil hole 3 of the shaft 1.
Due to the action of an impeller (not shown) provided inside, oil flows from one end of the shaft 1 through the inside of the oil hole 3 to the other end, and then passes between the shaft 1 and the bearing 5 before entering the casing 4. The oil flows between the shaft 2 and the rotor 6, then flows between the shaft 2 and the bearing 5, and flows again from one end of the shaft 1 to the oil sump 12, thereby coming into contact with the shaft 2 and the cam 2. Oil lubrication between the mating member and the mating member is performed.

However, problems with oil lubrication caused by using a camshaft made of a cast product are as follows. Since the cam 2 in the camshaft and shaft is a cast product, it does not permeate lubricating oil by itself. For this reason, the lubricating oil that has flowed into the casing 4 flows only through the contact portion between the cam 2 and the rotor 6, so the flow of the lubricating oil inside the casing 4 is poor. Therefore, the cam 2 and the rotor 6 have insufficient lubrication and are prone to wear, and as a result, the rotor 4 cannot rotate smoothly. Furthermore, the inner surface of the oil hole 3 of the shaft 1 is in the state of a cast surface, and it is not a smooth surface with many unevenness.

There is also a problem in that the flow of lubricating oil in the oil hole 3 is poor and lubrication of the camshaft is inhibited.

[Purpose of the invention]

The present invention was made based on the above-mentioned circumstances, and an object of the present invention is to provide a camshaft which is provided with sufficient oil lubrication and has high wear resistance.

[Summary of the invention]

The camshaft of the present invention is characterized in that it comprises a hollow shaft made of a molten material and a cam made of a sintered body fitted into the shaft, and the shaft and the cam are diffusion bonded. It is something.

That is, the shaft and the cam can be firmly joined by diffusion bonding, and the cam is made of a sintered body to allow lubricating oil to pass through, thereby increasing the lubricity between the cam and the mating member. This improves the flow of lubricating oil.

Hereinafter, a case in which the camshaft of the present invention is applied to a rotary drive in a rotary compressor will be explained with reference to FIGS. 3 and 4. In FIGS. 3 and 4, the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and explanations thereof will be omitted. The camshaft of the present invention is composed of a shaft 21 made of a metal tube and a cam 22 made of a sintered body eccentrically fitted to the shaft 21, and the shaft 21 and the cam 22 are fixed together by diffusion bonding. It is [there]. The metal tube forming the shaft 21 is made of Cr-M in consideration of strength and rigidity.

Uses steel pipes such as steel.

The sintered body forming the cam 22 has a weight ratio of 0.0 nickel.
5-2%, copper 0.05-2t, Mo 0.05-0.7
%, one or more paddy with less than 1% phosphorus, and car? N0.
A sintered alloy consisting of 5 to 3.5 inches and the remainder substantially iron is used. This iron-based sintered alloy has excellent strength and wear resistance. In addition, the sintered body has a porosity of more than 10% in order to allow good permeation of lubricating oil.

When manufacturing a camshaft, powder with a predetermined composition is pressurized to form a cam-shaped powder compact, a steel pipe is cut to a predetermined length, and the powder compact is fitted into the steel pipe. The powder compact is sintered in a furnace. During this sintering, the sintered body contracts with the powder compact and tightens the steel pipe, and at the same time, the sintered body and the steel pipe are mutually diffused and joined. Therefore, the shaft 2 is made of a steel pipe and the cam 22 is made of a sintered body.
and can be firmly joined together.

Further, the surface of the shaft 21 that comes into contact with the bearing 5 is subjected to a surface hardening treatment to provide wear resistance. Surface hardening treatments include ceramic coating, carburizing, and nitriding. The ceramic coating forms a coachin layer of Cr2O5+F@,04.

The outer peripheral surface of the cam 22 that comes into contact with the rotor 6 generates oxides. The oxide is produced by steam treatment. By producing the oxide, the outer circumferential surface of the sic cam 22 can be impregnated with oil retention, that is, lubricating oil.

However, the camshaft configured in this way has the cam 22
is made of a sintered body, so that the lubricating oil flowing into the casing 4 passes through the contact area between the cam 22 and the rotor 6, and also passes through the inside of the cam 22. Flow of lubricating oil is improved. Therefore, the cam 22 and the rotor 6 can be sufficiently lubricated to suppress wear. The steel pipe forming the shaft 21 is manufactured by a process such as drawing, and the inner hole surface thereof is a smooth surface. The inner hole 23 of this steel pipe becomes an oil hole through which lubricating oil flows.

Therefore, the lubricating oil is in the inner hole 2S of the steel pipe, that is, the shaft 21.
can flow smoothly and can be sufficiently supplied to the contact area between the camshaft and the mating member. Further, since the shaft 21 has been subjected to surface hardening treatment, wear caused by rotation can be suppressed. Further, since the outer circumferential surface of the cam 22 is formed with an oxide layer so as to be impregnated with lubricating oil, the contact portion between the cam 22 and the rotor 6 can be lubricated more reliably. .

[Embodiments of the invention]

A camshaft for a rotary compressor was manufactured using the method described below.

(1) Fe-Ni-Cu-Mo powder 96.9% by weight
A material powder was obtained by mixing 0.6% graphite, 2.5% Fe-12P, and 1 x zinc stearate, and this powder was pressed at a molding pressure of 5 tons/cm2 to form a cam-shaped powder compact. Shape. Cut the steel pipe to the specified length.

The outer diameter of this steel pipe is sized to have a clearance of approximately 60μ from the inner diameter of the cam.The powder compact is fitted into the steel pipe and sintered at a temperature of 1200°C for 30 minutes in a hydrogen atmosphere. The sintered body (cam) and steel pipe (
The camshaft was manufactured by diffusion bonding the camshaft.

(2) For the camshaft manufactured in Example (1),
After immersing in Cr 20s solution, drying and firing (550℃
x30 minutes) is repeated 10 times or more to form a coating layer of Cr2O3+Fe3O4 on the shaft.

(3) The shaft of the camshaft manufactured in Example (1) was subjected to carbonitriding treatment at a temperature of 780°C for 1 hour, followed by oil quenching, and then tempered at a temperature of 180°C for 1 hour. administer.

(4) The cam of the camshaft manufactured in Example (1) was subjected to steam treatment at a temperature of about 600° C. for 3 hours to form an oxide layer.

As a result of incorporating and operating the camshafts manufactured in Examples (1) to (4) in a rotary compressor, it was possible to lubricate the contact area between the camshaft and the mating member by supplying sufficient lubricating oil. I was able to use it for a long time.

〔Effect of the invention〕

As explained above, the camshaft of the present invention can perform good oil lubrication and can obtain excellent wear resistance.

[Brief explanation of the drawing]

1 and 2 are longitudinal and cross-sectional views respectively showing a rotary compressor equipped with a conventional camshaft, and FIGS. 3 and 4 are respectively a rotary compressor using a camshaft according to the present invention. FIG. 1...Shaft, 2...Cam, 4...Casing, 5...Bearing, 6...Rotor, 21...Shaft, 22...Cam. Applicant's agent Patent attorney Takeshi Suzue Phoneme 1 Figure 2

Claims (9)

[Claims] (1) A camshaft comprising a hollow shaft made of a melted material and a cam made of a sintered body fitted into the shaft, the shaft and the cam being diffusion bonded. (2) The camshaft according to claim 1, wherein the shaft is made of a steel tube. (3) The sintered body forming the cam has a composition of 0.05 to 2% nickel, 0.05 to 2% copper, 0.05 to 0.7% molybdenum, and 1% or less phosphorus by weight. Claim 1 is a sintered alloy consisting of one or more species, 0.5 to 3.5% carbon, and the balance substantially iron, and has a porosity exceeding 10%. Camshaft listed. (4) The camshaft according to claim 1 or 2, wherein the shaft is surface-treated. (5) The camshaft according to claim 4, wherein the surface treatment is a ceramic coating. (6) The camshaft according to claim 4, wherein the surface treatment is carburizing treatment. (7) The camshaft according to claim 4, wherein the surface treatment is nitriding treatment. (8) The camshaft according to claim 1 or 3, wherein the surface of the cam is subjected to oxidation treatment. (9) The camshaft according to any one of claims 1 to 8, which is used for driving a rotor of a rotary compressor.