| 摘要 |
<p>PURPOSE:To improve durability by a method wherein oil is fed to a crank chamber arranged in the housing of a variable capacity pump in the non-cargo handling state of a hydraulic system to replace oil in the crank chamber, lowering of a cooling effect and viscosity is suppressed, and lubrication of a slide part is promoted. CONSTITUTION:A relief valve 26 is arranged in the delivery passage 22a of a variable capacity pump 21. A delivery passage 22a arranged upper stream from the relief valve 26 is communicated to the crank chamber 4 of the pump 21 through a bypass passage 36, and an electromagnetic on-off valve 37 is located in the passage 36. In a non-cargo handling state, the bypass passage 36 is released by means of the on-off valve 37, and a small amount of oil delivered with the aid of the pump 21 is introduced in a crank chamber 4 through the bypass passage 36 to replace oil in the crank chamber 4.</p> |
