| 摘要 |
<p>PURPOSE:To reduce weight and obtain a simple constitution by installing a closed center system direction control valve in which all the posts are closed at a neutral position and a neutral bypass valve on the upstream side of the direction control valve and permitting the bypassing of the upstream side oil. CONSTITUTION:Neutral bypass valves ENV1 and ENV2 are arranged on the upstream side of the closed center system direction control valves VS, VA1-VA4, VA51, VA52, and VA6. When the closed system direction control valve is at a neutral position, the neutral bypass valve operates to drain the working oil in an upstream circuit of the direction control valve into an oil reservoir, and the hydraulic circuit is prevented from being broken. Therefore, the simple constitution is realized, and the precision and yield in manufacture can be improved, and weight can be reduced.</p> |
