Title:
WORK VEHICLE
Document Type and Number:
WIPO Patent Application WO/2019/182090
Kind Code:
A1
Abstract:
This work vehicle is provided with a loading and unloading hydraulic circuit (A) including at least a main hydraulic pump (31), a lifting arm cylinder (8), and a control valve (32), an auxiliary hydraulic pump (31), a negative-type parking brake device (PB), and a parking brake release hydraulic circuit (B2), and includes a loading and unloading operation hydraulic circuit (B1) provided upstream of the parking brake release hydraulic circuit, an emergency flow passage (80) for supplying hydraulic oil discharged from the auxiliary hydraulic pump during an emergency to the parking brake device via the loading and unloading operation hydraulic circuit, and a valve device (81) provided in the emergency flow passage, wherein the valve device is switched to a communicating position if the pressure in the parking brake release hydraulic circuit is lower than a brake release pressure for releasing a braked state of the parking brake device.
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Inventors:
MIZUTANI KEISHI (JP)
MATSUTANI RYOUSUKE (JP)
TANAKA SHINICHIRO (JP)
MATSUTANI RYOUSUKE (JP)
TANAKA SHINICHIRO (JP)
Application Number:
PCT/JP2019/012008
Publication Date:
September 26, 2019
Filing Date:
March 22, 2019
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
E02F9/22; B60T13/22; B60T13/68; B60T17/18; F15B11/028; F15B11/08; F15B20/00
Foreign References:
| JPH04133850A | 1992-05-07 | |||
| JP2008137561A | 2008-06-19 | |||
| JP2001158342A | 2001-06-12 | |||
| JPS5143311B2 | 1976-11-20 |
Other References:
See also references of EP 3660230A4
Attorney, Agent or Firm:
THE PATENT BODY CORPORATE TAKEWA INTERNATIONAL PATENT OFFICE (JP)
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