| 摘要 |
PROBLEM TO BE SOLVED: To heighten a seal connecting pressure to a ram shank, while securing an accurate ram shank forward/backward movement, and prevent a seal from damaging with a work being caused by a joint. SOLUTION: Inner diameter measurement of a recessed portion 23a is set slightly larger than an outer measurement of a seal ring 26, and an inner diameter measurement of a recessed portion 23b is set slightly larger than an outer measurement of a seal ring 28 and the like so that each ring 26 and the like is followed against the forward, backward movements of the ram shank 12. A processing oil and a gear oil being infiltrated between the recessed portions 23a, 23b and the seal ring 26 and the like branch off an air purge from an introduction route 20 into introduction routes 25a and 25b so as to be discharged from oil recovery routes 22a, 22 and 22b respectively. Even when a work W being caused by a joint and fastened around the ram shaft 12, is retreated, movement of the work W is restricted with a protruded stripe 16a of the seal ring 16 which has a smaller inner diameter than the outer shape measurement and, an encroachment of the work W into a seal 26b and the like can be prevented. |
