JPH0229427B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a piston pin.

In order to improve the fuel consumption rate, it is preferable to reduce the weight of the internal combustion engine, and in particular, reducing the weight of the reciprocating rotating portion of the piston is extremely effective in improving the fuel consumption rate. In order to reduce the weight of the reciprocating rotating portion of the piston, piston pins have been known in which the outer peripheral surface of fiber-reinforced metal is surrounded by a thin-walled hollow tube. This piston pin is made by first manufacturing a cylindrical fiber-reinforced metal piece,
Next, this metal piece is press-fitted into the thin-walled hollow tube, or inserted into the thin-walled hollow tube and bonded to form the metal piece. However, when a piston pin is manufactured using this method, if the thickness of the thin-walled hollow tube is reduced, the thin-walled hollow tube may buckle when a fiber-reinforced metal piece is press-fitted or inserted into the thin-walled hollow tube. There is a problem in that the thickness of the hollow tube cannot be reduced because the thin-walled hollow tube may no longer be a perfect circle after being press-fitted or inserted. Furthermore, such a conventional piston pin has the problem that the contact interface between the thin-walled hollow tube and the fiber-reinforced metal piece peels off.

The present invention provides a piston pin that prevents peeling at the contact interface between a thin-walled hollow tube and a cylindrical fiber-reinforced metal layer filled therein, and further reduces the weight of the thin-walled hollow tube by reducing the thickness of the thin-walled hollow tube. The purpose is to provide a manufacturing method.

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

FIG. 1 shows a cylindrical thin-walled hollow tube 1 made of metal that forms the outer peripheral wall surface of a piston pin. This thin-walled hollow tube 1 is formed from a steel tube whose outer peripheral surface has been subjected to boron infiltration treatment. As shown in FIG. 2, a large number of reinforcing fibers 2 oriented in the longitudinal axis direction of the thin-walled hollow tube 1 are inserted into the thin-walled hollow tube 1. Next, thin-walled hollow tube 1 filled with reinforcing fiber 2
is inserted into the pressure casting chamber 4 of the high pressure casting apparatus 3 (FIG. 3). As shown in FIG. 3, the pressure casting chamber 4 has a bottom portion 4a and a circular inner peripheral surface 4b, and the thin-walled hollow tube 1 is placed on the bottom portion 4a. Then,
A molten metal 5 of a metal such as aluminum or magnesium or an alloy such as an aluminum alloy or a magnesium alloy is poured into the pressure casting chamber 4 . Next, the molten metal 5 in the pressurized casting chamber 4 is pressurized, for example, by a piston 6. At this time, the molten metal 5 penetrates between the reinforcing fibers 2, and then the molten metal 5
When solidified, a fiber-reinforced metal layer 7 having a matrix of aluminum, magnesium, or an alloy thereof is formed inside the thin-walled hollow tube 1. Next, as shown in FIG. 4, the thin-walled hollow tube 1 is taken out from the pressure casting chamber 4, and the molten metal 5 solidified on the outer peripheral wall surface of the thin-walled hollow tube 1 is removed, for example, by cutting. In this way, a piston pin having the fiber-reinforced metal layer 7 formed inside is formed.

As can be seen from FIG. 3, according to the present invention, the same pressure is applied to the inner and outer peripheral surfaces of the thin-walled hollow tube 1 during pressure casting, so even if the thickness of the thin-walled hollow tube 1 is reduced, the thin-walled hollow tube 1 is not deformed, and the thin-walled hollow tube 1 of the piston pin thus manufactured has a perfect circle and is lightweight. In addition, by manufacturing the piston pin by the pressure casting method, the outer circumferential surface of the fiber-reinforced metal 7 is tightly joined to the inner circumferential surface of the thin-walled hollow tube 1. It is possible to prevent the contact interface with the inner circumferential surface of the hollow tube 1 from peeling off.

[Brief explanation of drawings]

Figure 1 is a side sectional view of a thin-walled hollow tube, Figure 2 is a side sectional view of a thin-walled hollow tube filled with reinforcing fibers, and Figure 3 is a side sectional view of a thin-walled hollow tube filled with reinforcing fibers.
The figure is a side cross-sectional view of the high-pressure casting apparatus, and FIG. 4 is a side cross-sectional view of the high-pressure cast thin-walled hollow tube and fiber-reinforced metal layer. DESCRIPTION OF SYMBOLS 1... Thin-walled hollow tube, 2... Reinforced fiber, 3... High pressure casting device, 4... Pressure casting chamber, 5... Molten metal, 7... Fiber reinforced metal layer.

Claims (1)

[Claims] 1 Fill the inside of a metal thin-walled hollow tube with reinforcing fibers, insert the thin-walled hollow tube filled with the fibers into a pressure casting chamber of a high-pressure casting device, and pour molten metal into the pressure casting chamber. The molten metal is poured into the inside of the thin-walled hollow tube and around the entire outer peripheral surface of the thin-walled hollow tube,
A fiber-reinforced metal layer containing the metal as a matrix inside the thin-walled hollow tube by pressurizing the molten metal in the pressurized casting chamber that is fed into the inside of the thin-walled hollow tube and around the entire outer peripheral surface of the thin-walled hollow tube. 1. A method for manufacturing a piston pin, which comprises forming a thin-walled hollow tube, and then removing an adhered metal layer on the outer wall of the thin-walled hollow tube.