To improve durability of a valve having a high rigidity area and a low rigidity area.
A hydraulic draft gear of the present invention comprises: a valve body formed with a second hydraulic passage; and a second valve 33 in which a central axis CL is fixed against the valve body, an opening end of the second hydraulic passage of the valve body is covered by the second valve, the second valve can be deformed in such a direction as one where it may be moved away from the valve body when a certain force is received from the valve body, a first through hole 33A is formed in a circumferential direction and a second through hole 33B has a lower rigidity against a force applied from the valve body as compared with that of a third through hole 33C against a virtual center line IL connecting a middle point CC of the first through hoe 33A in its circumferential direction and the center axis CL. The second valve 33 has a higher rigidity of a first corner part C1 of the first through hole 33A positioned at the second through hole 33B as compared with that a second corner part C2 of the first through hole 33A positioned at the third through hole 33C.
ITSUBO NORIYUKI
TANABE YASUYUKI
Fumio Ogata
Takeshi Senda