Hydraulic control device for v-belt type stepless speed change gear

Abstract

Abstract PURPOSE:To control the line pressure to conform to the minimum value, by setting a spring constant in a line pressure relief valve down to a non-linear characterstic one, while varying the setting length of a spring in accordance with a change gear ratio. CONSTITUTION:A line pressure relief valve 102 regulates the line pressure so as to cause it to balance the force produced by each of springs 152 and 154 and another force by throttle pressure in a port 146b. When a change gear ratio is small, a movable conical plate of a driving pulley moves in a direction where it should open, and a lever 158 rotates counterclockwise, while a sleeve 150 is in a state of being shifted toward the left, and the spring 154 which is short in its free length is in a state of incompressibility. Since the force of the spring 152 only acts on a spool 148, a spring constant is small whereby a variation in the line pressure to the travel of the sleeve 150 is as well small. When the sleeve 150 shifts toward the left beyond the specified value, the spring 154 gets compressed, and the spring constant becomes such one that is added by spring constants of these springs 152 and 154 whereby it grows large as well as a variation in the line pressure to the travel of the sleeve 150 becomes large.

Inventors

• 👤 Yoshihisa Anpo
• 👤 安保　佳寿
• 👤 Shigeaki Yamamuro
• 👤 重明 山室
• 👤 Yoshikazu Tanaka
• 👤 芳和 田中
• 👤 Haruyoshi Hisamura
• 👤 春芳 久村
• 👤 Hiroyuki Hirano
• 👤 弘之 平野

Bibliographic Details