| 摘要 |
<p>Front (E) and rear (B) oil chambers in a clamping cylinder (18) are connected by a connecting path (22) provided in a piston section (21) of a clamping ram (20) for oil flow, when the ram (20) moves for mold opening or mold closure, to prevent generating negative pressure in the clamping cylinder (18). Oil then also passes between the clamping cylinder (18) and a charge tank (19) via open-close valve (41). Thereafter this valve (41) is closed to move a further open-close valve (25) to close the connecting path (22) of the piston section clamping ram for tight clamping. The front oil chamber (E) of the clamping cylinder is kept at low pressure by a relief valve (40). During mold opening, oil is supplied to an oil chamber for valve opening (F) from an oil chamber for mold opening (C) via a through-hole (32) bored in the clamping ram (21) to open the connecting path (22). The front oil chamber (E) of the clamping cylinder (18) and the charge tank (19) are kept at low pressure throughout cycle, so they need not be pressure proof. The oil circuit for operating the further open-close valve (25) can be simple.</p> |
