Steel piston for integral internal combustion engine, internal combustion engine, vehicle and manufacturing method

Abstract

The invention relates to a steel piston for an integral internal combustion engine, the internal combustion engine, a vehicle and a manufacturing method. A piston part mainly comprises a first piston body and a second piston body. A piston ring groove and an oil returning hole are formed in the upper portion of the second piston body, and a piston skirt part is arranged at the lower portion of the second piston body. The second piston body is provided with a piston pin hole. The inner side of the upper portion of the second piston body is fixedly connected with the first piston body. A cavity between the inner side of the upper portion of the second piston body and the first piston body is a cooling oil cavity, and the interior of the first piston body is a piston combustion chamber. The second piston body and the first piston body comprise a first matching area located at the upper portion and a second matching area located at the lower portion. The first matching area comprises a welding column face downwards extending from the top of the first piston body, and a welding cylinder face extending downwards from the top of the second piston body and corresponding to the welding cylinder face downwards extending from the top of the first piston body. The two extending faces both extend to the cooling oil cavity.

Description

technical field [0001] The invention relates to the technical field related to the manufacture of internal combustion engines, in particular to a steel piston for an integral internal combustion engine, an internal combustion engine, a vehicle and a manufacturing method. Background technique [0002] In recent years, the engine is constantly developing in the direction of high strength and light weight. The volume of the engine is getting smaller and smaller, but the pressure and temperature in the cylinder are constantly increasing; this requires that the compression height of the piston should be short enough and the structural strength should be sufficient High, able to withstand higher mechanical and thermal loads. The importance of the compact arrangement of the overall piston structure as well as the cooling function and structural strength becomes more apparent at this time. [0003] At present, the ratio of compression height to bore diameter of diesel engine piston...

AI Technical Summary

Problems solved by technology

Since the weld position is arranged above the piston pin hole, it needs a sufficiently long piston compression height for arrangement, so the overall height of the piston is limited to a certain extent, and weld flash is easy to form after friction welding, especially for internal cooling oil. After the weld flash is formed in the cavity, it will inevitably affect the flow of cooling oil in the cooling oil cavity and affect the cooling effect

[0005] Chinese patent ZL200820021937.7 discloses a laser-welded forged steel integral piston with a closed inner cooling oil cavity, which includes a piston body and a piston ring body, which are integrated by laser welding, and an inner cooling oil is formed between the two after welding cavity, the cooling oil cavity communicates with the inner cavity of the piston through at least two oil inlet and outlet holes; this patent solves the problem of weld flash, but the arrangement of the weld on the piston skirt requires that the piston skirt must be reserved The groove of the weld seam, the height of this part will inevitably increase the overall height of the piston, and the volume of the piston cannot be further reduced

[0006] Chinese patent ZL201020144349.X discloses a new type of laser welded forged steel piston, which includes a forged piston ring and piston body. The piston ring and piston body are first combined through the welding area and the matching area, and then laser welded It is formed by welding in the welding area; the piston body between the ring groove and the combustion chamber forms a closed cooling oil chamber, and the cooling oil chamber communicates with the outside through the oil inlet and outlet holes; this patent can also solve the problem of weld flash , but there is also the problem of reserving the matching area and increasing the overall height of the piston

However, the fitting area below it is almost a Z-shaped structure with three fitting faces. However, in engineering applications, it is basically difficult to achieve the interference fit of the three faces at the same time, so one or two of them often appear. The non-interference fit of the surface, so that the strength required by the design cannot be achieved, and there are serious quality risks

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