JPS583963Y2 - piston pin - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piston pin that is attached to an engine or the like to connect a piston and a connecting rod.

Conventional engine piston pins, for example, have been hollow as shown in FIG. 1 or solid as shown in FIG. 2.

However, the piston pin receives a large compressive load via the piston boss during engine operation.

FIG. 3 shows the strain situation when the hollow piston pin shown in FIG. 1 receives this compressive load.

Since this hollow piston pin exhibits such strain behavior, cracks often occur in the boss portion of the piston pin.

In order to prevent this, a solid piston pin with high rigidity as shown in FIG. 2 has been devised in the past.

However, this solid piston pin inevitably causes an increase in overlap, which increases piston slap and accelerates cavitation damage to the cylinder liner.

The present invention has been developed in view of the above, and it is possible to obtain a completely integrated piston pin in which both ends that fit into the boss part of the piston are solid and the middle part of the housing is hollow. Therefore, both ends that receive compressive loads have high rigidity, are lighter than conventional solid ones, and more rigid than hollow ones, and have excellent strength. Moreover, they prevent piston slap and cavitation damage to the cylinder liner. The object of the present invention is to provide a piston pin that can prevent the above problems and also achieve dimensional accuracy that is exactly equivalent to that of a solid piston pin.

The configuration will be explained below based on the embodiment shown in FIG. 4 and below.

A hole 2at2b is made in the axial direction in the end face of each of the two solid rods 1atlb.

Then, these are welded together by friction welding with the surfaces having the holes 2at2b facing each other.

After welding, it is machined to the specified dimensions.

By doing so, both ends of the piston that fit into the boss portion are solid, and the middle portion where the connecting rod fits is hollow.

The piston pin according to the present invention is as detailed above, and consists of two solid rods 1 a t 1 b with holes 2 at 2 b drilled in the axial direction on one end surface, and a surface with holes 2 a t 2 b. Since they are opposed and welded together by friction welding, it is possible to obtain a completely integrated piston pin with both ends that fit into the piston boss part being solid and the middle part being hollow. The rigidity of both ends that receive compressive loads is high, and it is lighter than conventional solid ones, yet more rigid than hollow ones, and has excellent strength, and prevents piston slap and cavitation of the cylinder liner. Damage can be prevented.

Further, the dimensional accuracy can be obtained exactly the same as that of a solid piston pin.

[Brief explanation of the drawing]

Figures 1 and 2 are sectional views showing the conventional example, Figure 3 is an explanatory view showing the strain situation of the hollow piston pin, Figure 4,
5 and 6 are cross-sectional views showing an example of the manufacturing process of the piston pin according to the present invention.

Claims (1)

[Scope of utility model registration request] It is characterized by being made by welding two solid rods 1 a t 1 b with a hole 2 a t 2 b in the axial direction on one end surface by friction welding with the surfaces with the holes 2 at 2 b facing each other. piston pin.