Hydraulic system for work machine

A hydraulic system for a work machine comprising:

• an operation member to be moved to one direction and to the other direction;
• a hydraulic pump to output an operation fluid;
• a first fluid tube connected to the hydraulic pump;
• a first operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the one direction of the operation member, a pressure of the operation fluid to be outputted;
• a second operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the other direction of the operation member, a pressure of the operation fluid to be outputted;
• a hydraulic apparatus to be driven by the operation fluid outputted from the first operation valve or from the second operation valve;
• and
• a pressure changer to differentiate a pressure of the operation fluid that is supplied from the first operation valve to the hydraulic apparatus when the operation member is moved to the one direction from a pressure of the operation fluid that is supplied from the second operation valve to the hydraulic apparatus when the operation member is moved to the other direction.

A hydraulic system for a work machine comprising:

• an operation member to be moved to a first direction and to a second direction perpendicular to the first direction;
• a hydraulic pump to output an operation fluid;
• a first fluid tube connected to the hydraulic pump;
• a first operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to one direction in the first direction of the operation member, a pressure of the operation fluid to be outputted;
• a second operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the other direction in the first direction of the operation member, a pressure of the operation fluid to be outputted;
• a third operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to one direction in the second direction of the operation member, a pressure of the operation fluid to be outputted;
• a fourth operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the other direction in the second direction of the operation member, a pressure of the operation fluid to be outputted;
• a hydraulic apparatus to be driven by the operation fluid outputted from at least one of the first operation valve, the second operation valve, the third operation valve, and the fourth operation valve;
• and
• a pressure changer to differentiate a pressure of the operation fluid that is supplied from the first operation valve or the second operation valve to the hydraulic apparatus when the operation member is moved to the first direction from a pressure of the operation fluid that is supplied from the third operation valve or the fourth operation valve to the hydraulic apparatus when the operation member is moved to the second direction.

A hydraulic system for a work machine comprising:

• a hydraulic pump to output an operation fluid;
• a first hydraulic fluid connected to the hydraulic pump;
• a travel device to be activated by the operation fluid;
• a first operation device connected to the travel device, including a first operation member to be moved to one direction and to the other direction,
• a first operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the one direction of the first operation member, a pressure of the operation fluid, and
• a second operation valve connected to the first fluid tube, the first operation valve being configured to control, in accordance with the movement to the other direction of the first operation member, the pressure of the operation fluid;
• a second operation device connected to the travel device, the second operation device being other than the first operation device, including
• a second operation member to be moved to one direction and to the other direction,
• a third operation valve connected to the first fluid tube, the third operation valve being configured to control, in accordance with the movement to the one direction of the second operation member, the pressure of the operation fluid, and
• a fourth operation valve connected to the first fluid tube, the fourth operation valve being configured to control, in accordance with the movement to the other direction of the second operation member, the pressure of the operation fluid;
• a first select valve including
• an output port to output higher any one of the pressure of the operation fluid outputted from the first operation valve and the pressure of the operation fluid outputted from the third operation valve;
• a second select valve including
• an output port to output higher any one of the pressure of the operation fluid outputted from the second operation valve and the pressure of the operation fluid outputted from the fourth operation valve;
• a third select valve including
• an output port to output higher any one of the pressure of the operation fluid outputted from the output port of the first operation valve and the pressure of the operation fluid outputted from the output port of the second operation valve;
• a fourth fluid tube connected to the output port of the third select valve;
• and
• a brake device connected to the fourth fluid tube, the brake device to release a braking state of the travel device when the pressure of the operation fluid is applied to the brake device.