Patent ID: 7581392
Filing Date: 2009-09-01
Classification: B62D,E02F,F15B

Abstract:
1. A straight traveling hydraulic circuit comprising: first and second variable hydraulic pumps; a left traveling motor and a first working device connected to the first hydraulic pump; a plurality of switching valves installed in a flow path of the first hydraulic pump, and shifted to control hydraulic fluid fed to the left traveling motor and the first working device; a right traveling motor and a second working device connected to the second hydraulic pump; a plurality of switching valves installed in a flow path of the second hydraulic pump, and shifted to control the hydraulic fluid fed to the right traveling motor and the second working device; a straight traveling valve installed in the flow path of the second hydraulic pump, and shifted to supply the hydraulic fluid fed from the first hydraulic pump to the left traveling motor and the right traveling motor and to supply the hydraulic fluid fed from the second hydraulic pump to the first working device and the second working device, respectively; and a control valve installed in a branch flow path, which is branched from the flow path of the second hydraulic pump and connects an inlet part with an outlet part of the straight traveling valve, and shifted, when a combined operation in which the traveling and working devices are simultaneously driven is performed, to intercept a supply of the hydraulic fluid from the second hydraulic pump to the traveling motor via the straight traveling valve.