Search International and National Patent Collections

1. (WO2018180323) HYDRAULIC DRIVE DEVICE FOR WORKING VEHICLE

Pub. No.:    WO/2018/180323    International Application No.:    PCT/JP2018/008864
Publication Date: Fri Oct 05 01:59:59 CEST 2018 International Filing Date: Thu Mar 08 00:59:59 CET 2018
IPC: F15B 11/02
E02F 9/22
F15B 11/028
Applicants: KCM CORPORATION
株式会社KCM
Inventors: TANAKA Shinichiro
田中 真一郎
Title: HYDRAULIC DRIVE DEVICE FOR WORKING VEHICLE
Abstract:
Provided is a hydraulic drive device for a working vehicle, the hydraulic drive device being configured to reduce impact on an operator who operates an actuator. This hydraulic drive device for a working vehicle comprises: a variable displacement or fixed displacement main pump (1) for discharging pressurized oil; a main flow passage (F1) for supplying to an actuator the pressurized oil discharged from the main pump; a fixed displacement sub-pump (5) for discharging pressurized oil; a sub-flow passage (F2) for causing the pressurized oil discharged from the sub-pump to flow into the main flow passage and supplying the oil to an actuator (2); a flow combining switching valve (6A) for connecting or disconnecting the main flow passage and the sub-flow passage; a controller (30) for controlling the operation of the flow combining switching valve; and a relief valve (7A) provided in the sub-flow passage. The relief valve has pressure override characteristics which tend to cause a relief pressure to increase from a cracking pressure to a set pressure as a relief flow rate increases.