Construction machine energy regeneration apparatus

Abstract

A construction machine energy regeneration apparatus includes: a movable weight provided in a construction machine and movable vertically; and a power-transmitting hydraulic circuit, which moves the movable weight upward by utilizing energy that is generated when a boom, an arm, or a bucket moves in a gravitational direction or energy that is generated when a brake is applied to bring a turning unit or a running unit to a stop, and utilizes potential energy of the movable weight as energy for driving the boom or the arm.

1 . A construction machine energy regeneration apparatus of a construction machine, the construction machine including a first operating part and a second operating part, which are driven by a hydraulic fluid, the first operating part including a boom, a turning unit, or a running unit, the second operating part including an arm, a bucket, or an engine-assisting hydraulic motor, the construction machine energy regeneration apparatus comprising:
 a movable weight provided in the construction machine and movable vertically; and   a power-transmitting hydraulic circuit, which moves the movable weight upward by utilizing energy that is generated when the boom, the arm, or the bucket moves in a gravitational direction or energy that is generated when a brake is applied to bring the turning unit or the running unit to a stop, and utilizes potential energy of the movable weight as energy for driving the first operating part or the second operating part.   
     
     
         2 . The construction machine energy regeneration apparatus according to  claim 1 , comprising:
 a communication passage, through which a circuit of the first operating part or a circuit of the second operating part communicates with a circuit of the movable weight; and   a switching valve, which is provided on the communication passage and which switches a flow direction of the hydraulic fluid in the communication passage, wherein the switching valve shifts to a first position when the boom, the arm, or the bucket moves in the gravitational direction or when a brake is applied to bring the turning unit or the running unit to a stop, such that the hydraulic fluid flows through the communication passage and the switching valve to move the movable weight upward, and   the switching valve shifts to a second position when the movable weight moves in the gravitational direction, such that the hydraulic fluid flows through the communication passage and the switching valve to drive the first operating part or the second operating part.   
     
     
         3 . The construction machine energy regeneration apparatus according to  claim 1 , wherein
 the movable weight and a part of the power-transmitting hydraulic circuit have a function as a counter weight of the construction machine, and   a total mass of the movable weight and the part of the power-transmitting hydraulic circuit is substantially equal to a mass of a counter weight required by the construction machine.   
     
     
         4 . The construction machine energy regeneration apparatus according to  claim 1 , wherein
 the movable weight is supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder.   
     
     
         5 . The construction machine energy regeneration apparatus according to  claim 1 , wherein
 the movable weight is configured to be movable in a linear direction.   
     
     
         6 . The construction machine energy regeneration apparatus according to  claim 1 , wherein
 the movable weight is supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder,   the hydraulic cylinder includes a lifting cylinder and an assisting cylinder,   a distance between the fulcrum and a connection where the lifting cylinder is connected to the movable weight is set to be greater than a distance between the fulcrum and a connection where the assisting cylinder is connected to the movable weight,   the power-transmitting hydraulic circuit operates the lifting cylinder when the boom moves in the gravitational direction or when a brake is applied to bring the turning unit or the running unit to a stop, such that the movable weight swings upward, and   the power-transmitting hydraulic circuit operates the assisting cylinder when the movable weight swings downward to drive the first operating part or the second operating part.   
     
     
         7 . The construction machine energy regeneration apparatus according to  claim 1 , comprising:
 a solenoid pilot valve, which supplies a pilot pressure liquid to a pilot port of the switching valve;   a control valve, which controls a pressure and a flow rate of the hydraulic fluid supplied to the first operating part or the second operating part;   a remote control valve, which supplies a pilot pressure liquid to a pilot port of the control valve;   pressure sensors, which measure a supply pressure and a discharge pressure of the hydraulic fluid of the first operating part or the second operating part, or measure output pressures of the remote control valve, and generate pressure signals; and   a controller, which receives the pressure signals and transmits a command signal to the solenoid pilot valve based on the pressure signals.