JPS58138552A - Production of shaft member - Google Patents

Abstract

PURPOSE:To produce a lightweight shaft member having excellent hardness and abrasion resistant of surfaces, by mixing small steel pieces which are beforehand thermally hardened into a molten aluminum alloy, and casting the same centrifugally at the primary transformation point of iron or below. CONSTITUTION:An aluminum alloy contg. Al, Si, etc. is used as a base material, and is kept melted at about 580-700 deg.C lower than the primary transformation point (about 730 deg.C) of iron. Small steel pieces produced by subjecting, for example, carbon steel to high frequency hardening and grinding the same are used for said alloy, and the max. directional sizes are kept at about 0.5-3mm.. The small steel pieces are added at about 20-30wt% based on the total weight of the composite material. When the composite material is cast centrifugally, the samll steel pieces in a nonmolten state are distributed concentrically in the outside circumferential part, whereby sufficient hardness and abrasion resistance are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft member and a method for manufacturing a shaft member which is desired to have a hard surface and wear resistance, such as a camshaft for an internal combustion engine.

For example, a camshaft 1 for an internal combustion engine as shown in FIGS. 1 and 2 has a cam portion 2, a journal portion 3, and a shaft shaft 4 integrally formed by casting or forging. , normal cast iron is made entirely of iron-based materials such as special hook iron, and the surface is particularly hardened.
The nose part 2 of the cam part 2 where IL is approved is chill hardened. In addition, in the case of forging, we use carbon steel, chromium-based iron materials, and after forging the north part! JI for turtles! 11-wave quenching improves abrasion resistance.

In general, the FC, which is entirely made of iron-based material, is heavy and has the disadvantage of hindering the engine's performance. For this reason, attempts have been made to form the camshaft from 7" aluminum gold in the past, but in this case, the bearing (not shown) in the cam part 2, which has a thin line on the rocker arm 5, etc., has been tried. Since the dIJ conformability of the journal portion 3 is inferior to that of iron-based materials, it has not been put into practical use.

This invention addresses the above points and provides a method for manufacturing shaft members such as camshafts that are mainly made of aluminum alloy and are good, lightweight, and have excellent surface hardness and wear resistance. It is something.

That is, the method for manufacturing a shaft member according to the present invention includes:
A small piece of 11IIIO that has been thermally hardened in advance is mixed into a molten Al-1 alloy, and using this composite material,
Casting is performed using the centrifugal casting method at a casting temperature below the first east line point of steel, and due to the difference in specific gravity between the steel and the aluminum alloy, small pieces of copper are distributed throughout the 11km outer circumference of the shaft member. Once this is done, it is possible to easily obtain a shaft member with extremely high wear resistance and high movement.

Hereinafter, a first example of a dormitory in which this generation is applied to the above-mentioned internal combustion 1all camshaft will be explained.

First of all, as the aluminum alloy that becomes the base material, M is 81
and some other amounts of Ml, Mg,
The first transformation point of iron (approximately 7
The temperature is lower than the melting point of the m alloy (depending on the 81 content).
m) Bring the metal to a molten state, and mix small pieces of copper into it to form a mating material. The small pieces of this plow are thermally hardened, for example, by means of carbon steel t & frequency - philtral chill value, carburizing, etc., and then pulverized and good 1 or pre-pulverized t hardened by induction hardening, etc. The maximum dimension is 0.5 to 3-1!11 degrees.

In addition, it is important to ensure that the inside of this Kokatasha is sufficiently hardened.
11. Moreover, the mixing ratio line of this small piece is approximately 4 to 4 to 50% of the total amount of the composite material.

As mentioned above, a composite material company made by mixing a small piece of steel tube, the underarm is made of Al-8, and the #N1 order change of the original alloy is 580, which is less than 1 point.
By maintaining the temperature at ~700°C, t pieces of unmolten steel are mixed into the molten aluminum alloy, and the pieces of steel that have been thermally unified in advance are It is not annealed and maintains its aft.

Casting using the upper bale fitting material is carried out by a centrifugal casting method in which a cast #1 having a camshaft-shaped cavity is surrounded by a shaft 9 and cooled. Toward, -
In order to avoid annealing of the small pieces of ore, it is necessary to minimize the time that the small pieces are exposed to high temperatures. Therefore, it is desirable to pour and cool the metal quickly after the small pieces are mixed in.

The cast camshaft is completed by polishing the ** surfaces of the maximum IK force section 2 and journal section 3, and performing the necessary machining to bias the gears.

Now, according to the centrifugal casting described above, small pieces of copper, which have a higher specific gravity than the aluminum alloy that is the base material,
The polished cam portion 2 and journal portion 3 are concentrated on the outer periphery of the camshaft 1 and are in good condition with small copper pieces exposed on their outer surfaces. Therefore, it can be expected to have sufficient hardness and wear resistance as m class N with the rocker arm 5 and the bearing.

In particular, in the cam part 2, small pieces of steel 6 are collected relatively densely in the nose part 21 by centrifugal casting as shown in Figure 3Im, so the steel pieces increase as the valve lift increases. Worth the load! A hardness of 4t1 equivalent to 1Ijll can be obtained, and sufficient wear resistance ta can be maintained in the nose portion 2& without having to harden parts as in the conventional case.

Therefore, according to the above embodiment, it is possible to obtain a camshaft mainly made of aluminum alloy, which is lightweight and has high hardness and wear resistance on the surface of the force section 2 and journal section 3. .

If the mixing ratio of small pieces of - direction or - is too high, the bonding force of the aluminum alloy, which is the base material, will be weakened and it will become a web, and if it is too small, the effect of these small pieces of - will be negligible. Nine pieces that are not ground, as mentioned above, I-(capital) weight-
The best results can be obtained with a mixing ratio of IlIIL.

As is clear from the above description, according to the method for manufacturing a shaft member according to the present invention, it is possible to obtain a shaft member that is lightweight and has excellent surface hardness and wear resistance, such as a camshaft for an internal combustion engine. As shown in FIG. 1, since the surface is required to have a surface weight of 100 mm, it is suitable to use light metal for conventional steels, and it is possible to reduce the weight without reducing the wear resistance.

[Brief explanation of the drawing]

Is the first #A oblique indicating the general shape of the camshaft? ll
Fig. 3 is a cross-sectional view of the shaft due to the force caused by the koji-making method κ invented by Hitoshi Sono. 2... Force ▲ part, 3... Journal part, 6... Small piece of steel.

Claims (1)

[Claims] (1) A small piece of steel that has been thermally hardened in advance is mixed into a molten aluminum alloy, and using this material, centrifugation is performed at a casting temperature below the first transformation point of iron. 1. A method for manufacturing a shaft member, characterized by casting using a base method.