reciprocating internal combustion engine

Abstract

Reciprocating internal combustion engine with a connecting rod (100), a piston and a piston pin (200) for connecting the connecting rod (100) to the piston, wherein the connecting rod (100) comprises a small connecting rod eye (104) for receiving the piston pin (200), wherein no bushing is provided between the connecting rod (100) and the piston pin (200) and the piston pin (200) is nitrided, characterized in that the small connecting rod eye (104) is not hardened.

Description

[0001] The invention relates to a reciprocating piston internal combustion engine with a connecting rod, a piston and a piston pin for connecting the connecting rod to the piston, wherein the connecting rod comprises a small connecting rod eye for receiving the piston pin.

[0002] Typically, a connecting rod's small end bearing features a liner and a nitrided piston pin. A known alternative omits the liner, but hardens the small end bearing surface, and pairs the connecting rod with a piston pin with a DLC (diamond-like carbon) coating. This type of connecting rod is also used with a nitrided piston pin.

[0003] Using a cylinder liner results in additional costs due to the additional component and additional machining steps. A DLC-coated piston pin is expensive due to its coating and its higher-quality base material. Hardening the small connecting rod eye also results in higher costs.

[0004] From the document DE 10 2004 018 921 A1 a method is known for producing a connecting rod for a reciprocating piston engine comprising a crankshaft and piston, with a first connecting rod eye assigned to a piston and a second connecting rod eye assigned to the crankshaft, wherein in the first connecting rod eye a functional support is formed by heat treatment and in the second connecting rod eye a functional support is formed by coating the inner surface of the connecting rod eye, wherein the heat treatment and the coating are carried out in successive steps and the heat introduced in the first step is used for preheating in the second step.

[0005] The object of the invention is therefore to provide a reciprocating piston internal combustion engine as mentioned above, in the manufacture of which production steps can be omitted, a cheaper piston pin can be used and whose mass is reduced, so that the oscillating masses are reduced.

[0006] The problem is solved with a reciprocating piston internal combustion engine having the features of claim 1, in that the small connecting rod eye is not hardened, no bushing is provided between the connecting rod and the piston pin, and the piston pin is nitrided.

[0007] A particularly preferred embodiment of the invention is explained in more detail below with reference to the single figure, which shows a connecting rod according to the invention with a small connecting rod eye.

[0008] A reciprocating piston internal combustion engine (not shown in detail here), particularly for a motorcycle, comprises one or more cylinders. Each cylinder comprises a piston connected to a crankshaft of the internal combustion engine by means of a connecting rod 100, transmitting force and motion.

[0009] The connecting rod 100 has a shaft 102 and a large connecting rod eye (not shown) for connection to the crankshaft and a small connecting rod eye 104 for connection to the piston. According to the invention, the small connecting rod eye 104, in particular its running surface, is not hardened.

[0010] The small connecting rod eye 104 serves to accommodate a nitrided piston pin 200 for connection to the piston.

[0011] No liner is provided between the small connecting rod eye 104 and the piston pin 200, which means that the outer side of the piston pin 200 runs directly onto the inner surface of the small connecting rod eye 104 during operation of the internal combustion engine.

[0012] With the invention, production steps involving the tempering of the small connecting rod eye 104 or a cylinder liner can be eliminated, and it also provides the possibility of using a conventional nitrided piston pin 200. By eliminating the cylinder liner in the small connecting rod eye 104, weight is also saved, which leads to a reduction in the oscillating masses.

Claims

[1] Reciprocating piston internal combustion engine with a connecting rod (100), a piston and a piston pin (200) for connecting the connecting rod (100) to the piston, wherein the connecting rod (100) comprises a small connecting rod eye (104) for receiving the piston pin (200), wherein no bushing is provided between the connecting rod (100) and the piston pin (200) and the piston pin (200) is nitrided, characterized by that the small connecting rod eye (104) is not hardened.

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