Patent ID: 11885105
Assignee: KOBELCO CONSTRUCTION MACHINERY CO., LTD.
Field: Civil engineering (Other fields)
Classification: CPC E  F | IPC E  F

Claim 0:
1. A hydraulic control apparatus to be provided in a work machine that includes a first traveling body and a second traveling body, which are provided on left and right of the work machine and configured to perform respective traveling motions, and a work attachment configured to perform a work motion, the hydraulic control apparatus comprising:
a first pump that discharges hydraulic fluid;
a second pump that is separately provided from the first pump and discharges the hydraulic fluid;
a first traveling motor that is driven by supply of the hydraulic fluid to make the first traveling body perform the traveling motion;
a second traveling motor that is driven by supply of the hydraulic fluid to make the second traveling body perform the traveling motion;
a work actuator that is driven by supply of the hydraulic fluid to make the work attachment perform a target work motion included in the work motion;
a flow-path selector valve configured to make a flow-path switching motion for switching a flow path of the hydraulic fluid discharged by the first pump and the second pump, the flow-path switching motion shifted between
a first position for forming the flow path for allowing the hydraulic fluid discharged from the first pump to be supplied to the first traveling motor and allowing the hydraulic fluid discharged from the second pump to be supplied to the second traveling motor and the work actuator without being supplied to the first traveling motor, and
a second position for forming a first flow path for allowing the hydraulic fluid discharged from the first pump to be supplied to the work actuator and a second flow path for allowing the hydraulic fluid discharged from the second pump to be supplied to the first traveling motor and the second traveling motor and forming a communication flow path providing communication between the first flow path and the second flow path, the communication flow path having an opening area variable by the flow-path switching motion;

a driving state detector that detects a physical quantity which is an index of a driving state of the work actuator and varied with a variation in a load of the work actuator; and
a flow-path switching control unit that makes the flow-path selector valve perform the flow-path switching motion, the flow-path switching control unit configured to
shift the flow-path selector valve to the first position in a single operation state where only one of a target work operation that is an operation for making the work attachment perform the target work motion and a traveling operation that is an operation for making the first traveling motor and the second traveling motor perform the respective traveling motions, and
shift the flow-path selector valve to the second position in a combined operation state where the target work operation and the traveling operation are simultaneously performed, wherein

the physical quantity is selected from a target work motion speed which is a speed of the target work motion and an actuator thrust which is a thrust of the work actuator, and
the flow-path switching control unit
stores an allowable range of the physical quantity, the allowable range being set in correspondence with a target work operation amount which is a magnitude of the target work operation, and
operates the flow-path selector valve so as to make the opening area of the communication flow path smaller, in a case where the physical quantity detected by the driving state detector in the combined operation state is deviated from the allowable range corresponding to the target work operation amount, than the opening area in a case where the detected physical quantity is within the allowable range.