Cylinder, cylinder device, and working vehicle

Abstract

Provided is a hydraulic cylinder using oil pressure, etc., the hydraulic cylinder being configured so that the thickness of a head cover, etc. is reduced so that the hydraulic cylinder is lighter and has a small overall length. A head cover (3) which constitutes an end of a cylinder (1) and a cylinder tube (2) which constitutes the cylindrical portion of the cylinder (1) are welded together by a laser beam applied from the outside radially of the cylinder tube (2) toward the inside radially of the cylinder tube (2).

Description

technical field [0001] The present invention relates to cylinders, cylinder devices and work vehicles. More specifically, it relates to a cylinder welded by laser, a cylinder device, and a work vehicle including the cylinder device. Background technique [0002] Patent Document 1 discloses a fluid pressure cylinder in which a cylinder tube and a cylinder head constituting the cylinder are joined together by welding. [0003] Unlike pneumatic cylinders, hydraulic cylinders that use oil pressure, etc., as hydraulic cylinders, have a high-pressure internal working fluid. Therefore, in order to obtain a predetermined fatigue strength, it is necessary to deepen the fusion zone in the welding of the cylinder barrel and the cylinder head. The commonly used welding method is MAG welding (METAL ACTIVE GAS WELDING), which uses a mixture of inert gas and carbon dioxide as a shielding gas in arc welding, and implements a slope on the mating part of the cylinder barrel and cylinder head...

AI Technical Summary

Problems solved by technology

Here, when the fusion zone is deepened in order to ensure the fatigue strength, it is necessary to increase the heat input for welding, but in order to suppress the thermal deformation caused by the heat input, it is necessary to sufficiently thicken the thickness of the cylinder head of the hydraulic cylinder ( Image 6 Mark b), therefore, there is a problem that the cylinder becomes longer and the cylinder as a whole becomes heavier

[0006] In addition, by adding the welding repair material used in MAG welding, there is a problem that impurities adhere to the outside of the fusion zone, and cracks are generated starting from the impurities.

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