| 摘要 |
PURPOSE:To reduce the size of an apparatus, by a method wherein a counterbalance valve is provided with a bypass restriction passage, and opening and closing of the passage are controlled by a poppet operated by a line pressure. CONSTITUTION:The cunterbalance valve 40 is provided with the bypass restriction passage 56, and the poppet 37 is pressed against an opening part of the passage 56 by a control spring 39. When a change-over valve is changed over to apply brake in the condition wherein a motor is driven, the pressure inside a passage 28 is raised so that the poppet 37 is operated to open the passage 56. Even after the inertia body loses its inertia energy due to an action of a crossover relief valve, the bypass restriction passage 56 remains in an opened condition because the force of the control spring 39 is weak, so that the high pressure in the passage 28 is prevented from being confined in the passage 28. Accordingly, since reversion of the inertia body can be prevented without providing any ON-OFF valve separately from the counterbalance valve 10, the apparatus can be made to be small in size. |
