Patent Application
20130111888
The present disclosure relates to a pump associated with a hydraulic swing motor, and more particularly to a controller configured to adjust a torque output of the pump.
Top-swinging machines, for example, excavators, material handlers, and other types of heavy equipment used in mining and construction industry typically include an upper structure and a base. The upper structure is swingably attached to the base and includes an implement system having a boom, an arm and a bucket/shovel is pivotally mounted on the arm.
United State Published Application US20110020146A1 titled “Rotation Drive Controlling System For Construction Machine” published on Jan. 27, 2011 and assigned to Komatsu, Ltd. discloses a variable displacement hydraulic pump supplying a flow of the pressurized hydraulic fluid to a hydraulic motor. The hydraulic motor is configured to rotate the upper structure relative to the base of a top-swinging machine. A controller associated with the variable displacement hydraulic pump adjusts the displacement of the pump, when a pump discharge pressure exceeds a first limit. Moreover, the controller also cancels the adjustment when the pump discharge pressure falls below a second limit.
The present disclosure is directed to overcoming one or more of the problems as set forth above.
In one aspect, the present disclosure provides a hydraulic circuit configured to rotate an upper structure about a base. The hydraulic circuit includes a hydraulic swing motor, a pump, and a controller. The hydraulic swing motor has a first port and a second port, such that, a first motor conduit connected to the first port of the hydraulic swing motor and a second motor conduit connected to the second port of the hydraulic swing motor. The pump selectively supplies a flow of pressurized hydraulic fluid to the hydraulic swing motor through the first and the second motor conduits. Moreover, the controller electrically connected to the pump to adjust a torque output of the pump based on a swing speed of the hydraulic swing motor
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
As illustrated in
The operator station 26 may be configured to receive input from the operator to move the implement 20 and/or the upper structure 12. The operator station 26 may include one or more operator interface devices 28 embodied as single or multi-axis joysticks or levers or pedals located proximal an operator seat. The operator interface devices 28 may be proportional-type controllers configured to position and orient the implement 20 and/or the upper structure 12.
A first motor conduit 210 and a second motor conduit 212 originating from the control valve 206 may be connected to opposite sides of the hydraulic swing motor 16. The pump 202 may selectively supply a flow of pressurized hydraulic fluid to the hydraulic swing motor 16 through one of the first and the second motor conduits 210, 212 via the control valve 206. The hydraulic swing motor 16 may include a first port 214 and a second port 216. The first motor conduit 210 is hydraulically connected to the control valve 206 and to the first port 214 of the hydraulic swing motor 16. The second motor conduit 212 is hydraulically connected to the control valve 206 and to the second port 216 of the hydraulic swing motor 16. The pressurized hydraulic fluid flow from pump 202 may be also supplied to one or more control valves of various other hydraulic actuators associated with implement 20, the boom 18, and the like.
Hydraulic swing motor 16 may rotate in a first direction when the flow of pressurized hydraulic fluid supplies into the hydraulic swing motor 16 through the first port 214. Alternatively, the hydraulic swing motor 16 may rotate in a second direction when a flow of hydraulic fluid flows into the hydraulic swing motor 16 through the second port 216. The second direction is in opposing relationship to the first direction. Further, the hydraulic swing motor 16 may move the upper structure 12 (see
Control valve 206 may include a solenoid-operated direction control valve and movable between a first open position, wherein a flow path between the pump 202 and the first port 214 of the hydraulic swing motor 16 is defined, a second open position, wherein a flow path between the pump 202 and the second port 216 of the hydraulic swing motor 16 is defined, and a closed position, wherein the pump 202 and the hydraulic swing motor 16 are hydraulically blocked from each other. Alternatively, the control valve 206 may include an independent metering valve (IMV) system that includes plurality of independently-operated valves. Further, a tank conduit 223 may be provided between the control valve 206 and the tank 204. The pump conduit 208 and the tank conduit 223 may include a one-way check valve disposed therein to define a one-way flow of the hydraulic fluid. A pair of cross-line pressure relief valves 218, 220 may be provided to interconnect the first and the second motor conduits 210, 212. The pressure relief valves 218, 220 may allow an excessive pressure above a predetermined value in one of the first and second motor conduits 210, 212 to relieve to the other of the first and the second motor conduits 210, 212.
Still referring to
The controller 222 may include a signal input unit 228, a system memory 230, and a processor 232. The signal input unit 228 may be configured to receive a voltage or current signals from the speed sensors 227 and 229 corresponding to the engine speed and the swing speed, respectively. The system memory 230 may include for example, but not limited to, a Random Access Memory (RAM), a Read Only Memory (ROM), flash memory, a data structure, and the like. The system memory 230 may include a computer executable code to output the command signal based on the engine speed, the swing speed, the operator's input, and the pressure of the hydraulic fluid across the hydraulic swing motor 16. Moreover, the system memory 230 may also store a computer executable code to output a control signal to control a flow of the pressurized hydraulic fluid via the control valve 206. The system memory 230 may be operable on the processor 232 to output the command signal and the control signal to adjust the displacement of the swash plate 203 and also control the flow of the pressurized hydraulic fluid via the control valve 206.
As described above, the hydraulic swing motor 16 is configured to rotate the upper structure 12 of the machine 10. The hydraulic circuit 200 controls the flow of the pressurized hydraulic fluid to the hydraulic swing motor 16. According to an aspect of the present disclosure, the controller 222 may adjust the torque output of the pump 202 based on the real-time swing speed of the hydraulic swing motor 16. During operation, based on the signal from the operator interface device 28, the pump 202 may supply the flow of the pressurized hydraulic fluid to the hydraulic swing motor 16. The flow of the pressurized hydraulic fluid may accelerate the upper structure 12 and rise to a level which opens one of the cross-line pressure relief valves 218 or 220. The flow of the pressurized hydraulic fluid across one of the cross-line pressure relief valves 218 or 220 may flow back to the tank 204 via the tank conduit 223 or to one of the first port 214 and the second port 216 through one of the first and the second motor conduits 210, 212 depending on which of the port 214 or 216 is at the lower pressure.
The torque output of the pump 202 may be optimized to reduce any excess flow of the pressurized hydraulic fluid to the hydraulic swing motor 16. It may be apparent to a person skilled in the art that, by dynamically adjusting the torque output of the pump 202, more hydraulic energy may be available to the other hydraulic actuators associated with the boom 18, the implement 20, and the like.
Although various aspects of the present disclosure as described herein may be incorporated without departing from the scope of the following claims, it will be apparent to those skilled in the art that other modifications and variations can be made. Other variations will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
