Construction machine having hydraulic circuit
First Claim
1. A construction machine comprising:
- a lower propelling body;
an upper slewing body slewably mounted on the lower propelling body;
a working attachment attached to the upper slewing body, the working attachment including a boom raisable and lowerable with respect to the upper slewing body, an arm swingable with respect to the boom, a boom cylinder which is a hydraulic actuator for driving the boom, and an arm cylinder which is a hydraulic actuator for driving the arm;
right and left travel motors which are hydraulic actuators for driving the lower propelling body to make the lower propelling body travel;
a slewing motor which is a hydraulic actuators for driving the upper slewing body to slew the upper slewing body;
a hydraulic actuator circuit for operating the hydraulic actuators, the hydraulic actuator circuit including a first circuit connected to a first travel motor which is one of the right and left travel motors and to the boom cylinder, a second circuit connected to a second motor which is the other of the right and left travel motors and to the arm cylinder, and a third circuit connected to the slewing motor, and each of the first to third circuits having a control valve associated with a corresponding one of the hydraulic actuators to control an operation of the hydraulic actuator;
a first pump for discharging hydraulic fluid toward the first circuit;
a second pump for discharging hydraulic fluid toward the second circuit;
and a third pump for discharging hydraulic fluid toward the third circuit, wherein;
the first travel motor is disposed on an upstreammost side in the first circuit so as to give the first travel motor a priority to be driven;
the second travel motor is disposed on an upstreammost side in the second circuit so as to give the second travel motor a priority to be driven; and
the hydraulic actuator circuit further includes a merging valve for merging hydraulic fluid discharged from the third pump toward the third circuit into each of the first and second circuits, the first merging valve having a first position for unloading the hydraulic fluid discharged from the third pump through the second circuit when none of the hydraulic actuators other than the first and second travel motors is operated, a second position for merging the hydraulic fluid discharged from the third pump into each of the first and second circuits when a double travel operation, which is an operation for simultaneously operating the first and second travel motors, and an operation on at least one of the remaining hydraulic actuators except for a boom raising operation which is an operation for raising the boom are performed, and a third position for merging the hydraulic fluid discharged from the third pump into the first circuit while blocking the hydraulic fluid from the second circuit when the boom raising operation is performed.
1 Assignment
0 Petitions
Accused Products
Abstract
A construction machine includes a hydraulic actuator circuit including: a first circuit connected to one of travel motors and a boom cylinder; a second circuit connected to the other travel motor and arm cylinder; and a third circuit connected to a slewing motor; control valves for hydraulic actuators; and a merging valve having a first position for unloading hydraulic fluid discharged from a third pump upon no operation except for two travel motors; a second position for merging the hydraulic fluid into the first and second circuits upon a simultaneous operation of the travel motors and an operation of at least one remaining hydraulic actuator except for a boom raising operation; and a third position for merging the hydraulic fluid into the first circuit while blocking it from the second circuit upon the boom raising operation.
6 Citations
9 Claims
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1. A construction machine comprising:
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a lower propelling body; an upper slewing body slewably mounted on the lower propelling body; a working attachment attached to the upper slewing body, the working attachment including a boom raisable and lowerable with respect to the upper slewing body, an arm swingable with respect to the boom, a boom cylinder which is a hydraulic actuator for driving the boom, and an arm cylinder which is a hydraulic actuator for driving the arm; right and left travel motors which are hydraulic actuators for driving the lower propelling body to make the lower propelling body travel; a slewing motor which is a hydraulic actuators for driving the upper slewing body to slew the upper slewing body; a hydraulic actuator circuit for operating the hydraulic actuators, the hydraulic actuator circuit including a first circuit connected to a first travel motor which is one of the right and left travel motors and to the boom cylinder, a second circuit connected to a second motor which is the other of the right and left travel motors and to the arm cylinder, and a third circuit connected to the slewing motor, and each of the first to third circuits having a control valve associated with a corresponding one of the hydraulic actuators to control an operation of the hydraulic actuator; a first pump for discharging hydraulic fluid toward the first circuit; a second pump for discharging hydraulic fluid toward the second circuit; and a third pump for discharging hydraulic fluid toward the third circuit, wherein; the first travel motor is disposed on an upstreammost side in the first circuit so as to give the first travel motor a priority to be driven; the second travel motor is disposed on an upstreammost side in the second circuit so as to give the second travel motor a priority to be driven; and the hydraulic actuator circuit further includes a merging valve for merging hydraulic fluid discharged from the third pump toward the third circuit into each of the first and second circuits, the first merging valve having a first position for unloading the hydraulic fluid discharged from the third pump through the second circuit when none of the hydraulic actuators other than the first and second travel motors is operated, a second position for merging the hydraulic fluid discharged from the third pump into each of the first and second circuits when a double travel operation, which is an operation for simultaneously operating the first and second travel motors, and an operation on at least one of the remaining hydraulic actuators except for a boom raising operation which is an operation for raising the boom are performed, and a third position for merging the hydraulic fluid discharged from the third pump into the first circuit while blocking the hydraulic fluid from the second circuit when the boom raising operation is performed. - View Dependent Claims (2, 3, 4)
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5. A construction machine comprising:
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a lower propelling body; an upper slewing body slewably mounted on the lower propelling body; a working attachment attached to the upper slewing body, the working attachment including a boom raisable and lowerable with respect to the upper slewing body, an arm swingable with respect to the boom, a boom cylinder which is a hydraulic actuator for driving the boom, and an arm cylinder which is a hydraulic actuator for driving the arm; right and left travel motors which are hydraulic actuators for driving the lower propelling body to make the lower propelling body travel; a slewing motor which is a hydraulic actuators for driving the upper slewing body to slew the upper slewing body; a hydraulic actuator circuit for operating the hydraulic actuators, the hydraulic actuator circuit including a first circuit connected to a first travel motor which is one of the right and left travel motors and to the boom cylinder, a second circuit connected to a second motor which is the other of the right and left travel motors and to the arm cylinder, and a third circuit connected to the slewing motor, and each of the first to third circuits having a control valve associated with a corresponding one of the hydraulic actuators to control an operation of the hydraulic actuator; a first pump for discharging hydraulic fluid toward the first circuit; a second pump for discharging hydraulic fluid toward the second circuit; and a third pump for discharging hydraulic fluid toward the third circuit, wherein; the first travel motor is disposed on an upstreammost side in the first circuit so as to give the first travel motor a priority to be driven; the second travel motor is disposed on an upstreammost side in the second circuit so as to give the second travel motor a priority to be driven; and the hydraulic actuator circuit further includes a merging valve for merging hydraulic fluid discharged from the third pump toward the third circuit into each of the first and second circuits, the merging valve having a first position for unloading the hydraulic fluid discharged from the third pump through the second circuit when none of the hydraulic actuators other than the first and second travel motors is operated, a second position for merging the hydraulic fluid discharged from the third pump into each of the first and second circuits when a double travel operation, which is an operation for simultaneously operating the first and second travel motors, and an operation on at least one of the remaining hydraulic actuators except for a boom raising operation which is an operation for raising the boom are performed, and a third position for merging hydraulic fluid discharged from the third pump into the first circuit while blocked the hydraulic fluid from the second circuit only when both of the boom raising operation and a slewing operation by the slewing motor are performed. - View Dependent Claims (6, 7, 8, 9)
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Specification