Hydraulic system for work machine

A hydraulic system for a work machine, comprising:

• a prime mover;
• a setup member via which a target revolution speed of the prime mover is set;
• a hydraulic pump to be operated by the prime mover to output an operation fluid;
• an operation valve to receive the operation fluid outputted from the hydraulic pump to set a pressure of the operation fluid outputted from the hydraulic pump to be a first pressure;
• a hydraulic device to be operated by the operation fluid passing through the operation valve;
• a memory to store first control characteristics indicating relations between the first pressure and an actual revolution speed of the prime mover, the relations each being defined by different slopes;
• and
• a controller to set the first pressure based on the first control characteristics when a load equal to or more than a threshold value is applied to the prime mover.

A hydraulic system for a work machine, comprising:

• a prime mover;
• a setup member via which a target revolution speed of the prime mover is set;
• a hydraulic pump to be operated by the prime mover to output an operation fluid;
• an operation valve to receive the operation fluid outputted from the hydraulic pump to set a pressure of the operation fluid outputted from the hydraulic pump to be a first pressure;
• a hydraulic device to be operated by the operation fluid passing through the operation valve;
• a memory to store
• first control characteristics indicating relations between the first pressure and an actual revolution speed of the prime mover, the relations being defined by lines each having parallel or different slopes, and
• a second control characteristic indicating a relation between the first pressure and the actual revolution speed of the prime mover;
• and
• a controller to set the first pressure based on the second control characteristic when a dropping amount of the actual revolution speed from the target revolution speed is less than a threshold value and to set the first pressure based on the first control characteristics determined corresponding to the target revolution speed when the dropping amount of the actual revolution speed from the target revolution speed is the threshold value or more.

A hydraulic system for a work machine comprising:

• a prime mover;
• a setup member via which a target revolution speed of the prime mover is set;
• a hydraulic pump to be operated by the prime mover to output an operation fluid;
• an operation valve to receive the operation fluid outputted from the hydraulic pump to set a pressure of the operation fluid outputted from the hydraulic pump to be a first pressure;
• a hydraulic device to be operated by the operation fluid passing through the operation valve;
• a memory to store first control characteristics indicating relations between the first pressure and an actual revolution speed of the prime mover, the relations each being defined by different slopes;
• and
• a controller to set the first pressure based on the first control characteristics determined corresponding to the target revolution speed when the dropping amount of the actual revolution speed from the target revolution speed is a threshold value or more.