| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a rod for a construction machine, which can extend a service life by preventing problems, such as cracks in a female groove or damage to a coupling pin, as much as possible.SOLUTION: In a drilling rod 30, a female rod 31 having a female cylindrical part 31a and a male rod 32 having a male shaft part 32a are coupled so that they can transmit torque to form an approximately U-shaped female groove 31c that extends in the direction orthogonal to the rod shaft direction on an inner wall surface 31b of the female cylindrical part 31a and to form an approximately U-shaped male groove 32c that extends in the direction orthogonal to the rod shaft direction in a peripheral surface 32b of the male shaft part 32a. A coupling pin 33 is inserted between the female groove 31c and the male groove 32c to restrict the relative displacement of the female rod 31 and the male rod 32 in the rod shaft direction. When looking at a cross section orthogonal to the rod shaft direction at a height of a shaft center O1 of the coupling pin 33, the male groove 32c is formed in a circular arc shape that becomes distant from the coupling pin 33 from a central part 32c1 toward both ends 32c2 and 32c3.</p> |
