US20150315768A1 - Construction machine with floating function - Google Patents

Construction machine with floating function Download PDF

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Publication number
US20150315768A1
US20150315768A1 US14/652,012 US201214652012A US2015315768A1 US 20150315768 A1 US20150315768 A1 US 20150315768A1 US 201214652012 A US201214652012 A US 201214652012A US 2015315768 A1 US2015315768 A1 US 2015315768A1
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US
United States
Prior art keywords
dozer
floating
flow path
check valve
cylinder
Prior art date
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Abandoned
Application number
US14/652,012
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English (en)
Inventor
Won-Cheol Jeong
Se-Rib Jee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Volvo Construction Equipment AB
Original Assignee
Volvo Construction Equipment AB
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Filing date
Publication date
Application filed by Volvo Construction Equipment AB filed Critical Volvo Construction Equipment AB
Assigned to VOLVO CONSTRUCTION EQUIPMENT AB reassignment VOLVO CONSTRUCTION EQUIPMENT AB ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: JEE, SE-RIB, JEONG, WON-CHEOL
Publication of US20150315768A1 publication Critical patent/US20150315768A1/en
Abandoned legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E02F3/844—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2285—Pilot-operated systems
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2292—Systems with two or more pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/003—Systems with load-holding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/3051—Cross-check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
    • F15B2211/3127—Floating position connecting the working ports and the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/77—Control of direction of movement of the output member
    • F15B2211/7741—Control of direction of movement of the output member with floating mode, e.g. using a direct connection between both lines of a double-acting cylinder

Definitions

  • the present invention relates to a construction machine having a floating function. More particularly, the present invention relates to such a construction machine having a floating function, which can perform a ground leveling work or a grading work in which the ground is flattened and leveled using a dozer blade.
  • the floating function means a function in which a dozer blade is moved upwardly and downwardly along a rugged ground surface by its own weight or an external force even without a manipulation of a manipulation lever by an operator during the traveling of the construction machine. Even when the construction machine is simply manipulated to be traveled by the floating function, a ground leveling work or a grading work can be performed in which the ground is flattened and leveled by the dozer blade moved upwardly and downwardly.
  • a construction machine having a floating function in accordance with the prior art includes:
  • a hydraulic pump 2 and a pilot pump 3 which are connected to an engine 1 ;
  • a dozer cylinder 4 connected to the hydraulic pump and configured to move a dozer blade (not shown) upwardly and downwardly;
  • a dozer check valve 6 installed in a flow path between the control valve 5 and the dozer cylinder 4 ;
  • a return check valve 8 installed in a flow path between the control valve 5 and a hydraulic tank 7 ;
  • a solenoid valve 9 for floating openably/closably installed in a signal path 13 between the pilot pump 3 and the dozer check valve 6 and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump 3 to the dozer check valve 6 to release a check function of the dozer check valve 6 .
  • a hydraulic fluid discharged from the hydraulic pump 2 is adjusted in flow rate by a dozer spool 5 a of the control valve 5 , and then is supplied to the dozer check valve 6 .
  • the hydraulic fluid supplied to the dozer check valve 6 converts the state of a pair of check valves of the dozer check valve 6 into an open state, and is introduced into a large chamber or a small chamber of the dozer cylinder 4 .
  • the introduced hydraulic fluid drives a piston of the dozer cylinder 4 so that the dozer blade (not shown) can be moved vertically.
  • a hydraulic fluid discharged from the dozer cylinder 4 by the drive of the piston of the dozer cylinder 4 passes through the dozer check valve 6 , the dozer spool 5 a , and the control valve 5 in this order and is returned to a hydraulic tank 7 via the return check valve 8 .
  • a spool of the solenoid valve 9 for floating is shifted to the bottom on the drawing sheet in response to an electrical control signal applied to the solenoid valve 9 for floating.
  • a pair of check valves within the dozer check valve 6 is converted to an open state by a pilot signal pressure discharged from the pilot pump 3 and applied to the dozer check valve 6 via the solenoid valve for floating 9 .
  • the conversion of the dozer check valve 6 releases a check function of restricting the returning of a hydraulic fluid to the dozer cylinder 4 .
  • a piston of the dozer cylinder 4 is driven by the dozer clylinder's own weight or an external force so that the dozer blade can be moved vertically along a rugged ground surface.
  • the supply and discharge of the hydraulic fluid to and from the dozer cylinder 4 is not performed smoothly in the floating mode, thus leading to a decrease in the vertical movement speed of the dozer cylinder 4 . That is, if the downward movement speed or the descending speed of the dozer blade is decreased, the dozer blade will ascend and will be kept for a long period of time in a state in which the dozer blade is spaced apart from the ground surface.
  • the dozer blade in the process in which the dozer blade is moved upwardly or ascends in the floating mode, if a back pressure is formed in the flow path along which the hydraulic fluid discharged from the dozer cylinder 4 is returned, the dozer blade cannot ascend easily along the rugged ground surface.
  • the hydraulic fluid discharged from the dozer cylinder 4 by the drive of the dozer cylinder 4 is returned to the hydraulic tank 7 via the control valve 5 , the dozer spool 5 a , and the return check valve 8 in this order.
  • the ascending of the dozer blade is interfered by the back pressure formed in the flow path along which the hydraulic fluid discharged from the dozer cylinder 4 is returned.
  • the conventional construction machine having a floating function entails a problem in that because the vertical movement speed of the dozer blade is relatively decreased as compared the traveling speed of the construction machine, the dozer blade does not ascend or descend smoothly along the rugged ground surface, resulting in a deterioration of workability in the ground leveling work.
  • the present invention has been made to solve the aforementioned problems occurring in the prior art, and it is an object of the present invention to provide a construction machine having a floating function in which when a ground leveling work or a grading work is performed by a floating function of a dozer blade, the vertical movement speed of the dozer blade can be increased, thereby improving workability.
  • a construction machine having a floating function including:
  • a dozer cylinder connected to the hydraulic pump and configured to move a dozer blade upwardly and downwardly;
  • control valve installed in a flow path between the hydraulic pump and the dozer cylinder and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder;
  • a dozer check valve installed in a flow path between the control valve and the dozer cylinder
  • a return check valve installed in a flow path between the control valve and a hydraulic tank
  • a solenoid valve for floating openably/closably installed in a signal path between the pilot pump and the dozer check valve and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump to the dozer check valve to release a check function of the dozer check valve;
  • check valve installed in the flow path for floating, the check valve being configured to allow a hydraulic fluid to be supplied from the hydraulic tank to the dozer cylinder through the flow path for floating in a floating mode and to block the flow path for floating when the floating mode is released.
  • a construction machine having a floating function including:
  • a dozer cylinder connected to the hydraulic pump and configured to move a dozer blade upwardly and downwardly;
  • control valve installed in a flow path between the hydraulic pump and the dozer cylinder and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder;
  • a dozer check valve installed in a flow path between the control valve and the dozer cylinder
  • a return check valve installed in a flow path between the control valve and a hydraulic tank
  • a solenoid valve for floating openably/closably installed in a signal path between the pilot pump and the dozer check valve and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump to the dozer check valve to release a check function of the dozer check valve;
  • pilot check valve installed in the flow path for floating to open or close the flow path for floating, the pilot check valve being configured to be shifted to an open state by a pilot signal pressure supplied to the dozer check valve to supply a hydraulic fluid from the hydraulic tank to the dozer cylinder through the flow path for floating or to allow the hydraulic fluid discharged from the dozer cylinder to be returned to the hydraulic tank through the flow path for floating in a floating mode, and shifted to a closed state by interruption of the supply of the pilot signal pressure to the dozer check valve to block the flow path for floating when the floating mode is released.
  • a construction machine having a floating function including:
  • a dozer cylinder connected to the hydraulic pump and configured to move a dozer blade upwardly and downwardly;
  • control valve installed in a flow path between the hydraulic pump and the dozer cylinder and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder;
  • a dozer check valve installed in a flow path between the control valve and the dozer cylinder
  • a return check valve installed in a flow path between the control valve and a hydraulic tank
  • a solenoid valve for floating openably/closably installed in a signal path between the pilot pump and the dozer check valve and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump to the dozer check valve to release a check function of the dozer check valve;
  • a 3-way valve installed at a crossing point of the flow path for floating and the flow path on the control valve side, the 3-way valve being configured to be shifted to a first position by a pilot signal pressure supplied to the dozer check valve to replenish a hydraulic fluid from the hydraulic tank to the dozer cylinder through the flow path for floating in a floating mode and shifted to a second position, in which the supply of the pilot signal pressure to the dozer check valve is interrupted to connect the flow path between the control valve and the dozer cylinder when the floating mode is released.
  • a construction machine having a floating function including:
  • a dozer cylinder connected to the hydraulic pump and configured to move a dozer blade upwardly and downwardly;
  • control valve installed in a flow path between the hydraulic pump and the dozer cylinder and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder;
  • a dozer check valve installed in a flow path between the control valve and the dozer cylinder
  • a return check valve installed in a flow path between the control valve and a hydraulic tank
  • a solenoid valve for floating openably/closably installed in a signal path between the pilot pump and the dozer check valve and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump to the dozer check valve to release a check function of the dozer check valve;
  • a 3-way valve installed at a crossing point of the flow path for floating and the flow path on the control valve side, the 3-way valve being configured to be shifted to a first position by a pilot signal pressure supplied to the dozer check valve to allow the dozer cylinder, the control valve, and the hydraulic tank to fluidically communicate with one another in a floating mode and shifted to a second position in which the supply of the pilot signal pressure to the dozer check valve is interrupted to connect the flow path between the control valve and the dozer cylinder when the floating mode is released.
  • the flow path for floating may be connected at the other end thereof to a large chamber of the dozer cylinder.
  • the flow path for floating may be connected at the other end thereof to a small chamber of the dozer cylinder.
  • the construction machine having a floating function in accordance with the present invention as constructed above has the following advantages.
  • the hydraulic fluid is replenished to the dozer cylinder or the discharge of the hydraulic fluid from the dozer cylinder is promoted to increase the drive speed of the piston so that the dozer blade can be smoothly moved vertically along the rugged ground surface, thereby improving workability in the ground leveling work or the grading work.
  • FIG. 1 is a hydraulic circuit diagram of a construction machine in accordance with the prior art
  • FIG. 2 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a first preferred embodiment of the present invention
  • FIG. 3 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a second preferred embodiment of the present invention
  • FIG. 4 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a third preferred embodiment of the present invention.
  • FIG. 5 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a fourth preferred embodiment of the present invention.
  • FIG. 2 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a first preferred embodiment of the present invention.
  • the construction machine having a floating function includes a normal mode in which a dozer blade is moved vertically by the manipulation of a manipulation lever and a floating mode in which the dozer blade is moved vertically along a rugged ground surface by its own weight or an external force during the traveling of the construction machine.
  • the construction machine having a floating function in accordance with a first preferred embodiment of the present invention includes:
  • a hydraulic pump 2 and a pilot pump 3 which are connected to an engine 1 ;
  • a dozer cylinder 4 connected to the hydraulic pump and configured to move a dozer blade (not shown) upwardly and downwardly;
  • control valve 5 installed in a flow path between the hydraulic pump 2 and the dozer cylinder 4 and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder 4 ;
  • a dozer check valve 6 installed in a flow path between the control valve 5 and the dozer cylinder 4 ;
  • a return check valve 8 installed in a flow path between the control valve 5 and a hydraulic tank 7 ;
  • a solenoid valve 9 for floating openably/closably installed in a signal path 13 between the pilot pump 3 and the dozer check valve 6 and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump 3 to the dozer check valve 6 to release a check function of the dozer check valve 6 ;
  • a flow path 12 for floating connected at one end thereof to the hydraulic tank 7 and connected at the other end thereof to a flow path for connecting the control valve 5 to the dozer cylinder 4 ;
  • check valve 10 installed in the flow path 12 for floating, the check valve being configured to allow a hydraulic fluid to be supplied from the hydraulic tank 7 to the dozer cylinder 4 through the flow path 12 for floating in a floating mode and to block the flow path for floating when the floating mode is released.
  • the flow path 12 for floating may be connected at the other end thereof to a large chamber of the dozer cylinder 4 .
  • the flow path 12 for floating may be connected at the other end thereof to a small chamber of the dozer cylinder 4 .
  • a configuration of the construction machine having a floating function in accordance with a first preferred embodiment of the present invention is the same as that of the construction machine having a floating function in accordance with the prior art shown in FIG. 1 , except the check valve 10 installed in the flow path 12 for floating.
  • the check valve 10 installed in the flow path 12 for floating.
  • a spool of the solenoid valve 9 for floating is shifted to the bottom on the drawing sheet in response to an electrical control signal applied to the solenoid valve 9 for floating.
  • a pair of check valves within the dozer check valve 6 is converted to an open state by a pilot signal pressure discharged from the pilot pump 3 and applied to the dozer check valve 6 via the solenoid valve for floating 9 .
  • the conversion of the dozer check valve 6 releases a check function of restricting the supply of a hydraulic fluid to the dozer cylinder 4 .
  • a piston of the dozer cylinder 4 is driven by the dozer clylinder's own weight or an external force so that the dozer blade can be moved vertically along a rugged ground surface.
  • the vertical movement speed of the dozer blade can be increased in the floating mode of the dozer blade. That is, a dozer spool 5 a of the control valve 5 is maintained in a neutral state in the floating mode so that the hydraulic fluid from the hydraulic tank 7 can be supplied to the large chamber of the dozer cylinder 4 via the check valve 10 installed in the flow path 12 for floating in a state in which the supply of the hydraulic fluid from the hydraulic pump 2 to the dozer cylinder 4 is interrupted. For this reason, the hydraulic fluid from the hydraulic tank 7 is replenished to the large chamber of the dozer cylinder 4 via the flow path 12 for floating upon the descending of the dozer blade, thus leading to an increase in the downward movement speed or the descending speed of the dozer blade.
  • the hydraulic fluid from the hydraulic tank 7 is replenished to the large chamber of the dozer cylinder 4 through the check valve 10 installed in the flow path 12 for floating so that the downward movement speed or the descending speed of the dozer blade can be increased.
  • FIG. 3 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a second preferred embodiment of the present invention.
  • the construction machine having a floating function includes a normal mode in which a dozer blade is moved vertically by the manipulation of a manipulation lever and a floating mode in which the dozer blade is moved vertically along a rugged ground surface by its own weight or an external force during the traveling of the construction machine.
  • the construction machine having a floating function in accordance with a second preferred embodiment of the present invention includes:
  • a hydraulic pump 2 and a pilot pump 3 which are connected to an engine 1 ;
  • a dozer cylinder 4 connected to the hydraulic pump and configured to move a dozer blade (not shown) upwardly and downwardly;
  • control valve 5 installed in a flow path between the hydraulic pump 2 and the dozer cylinder 4 and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder 4 ;
  • a dozer check valve 6 installed in a flow path between the control valve 5 and the dozer cylinder 4 ;
  • a return check valve 8 installed in a flow path between the control valve 5 and a hydraulic tank 7 ;
  • a solenoid valve 9 for floating openably/closably installed in a signal path 13 between the pilot pump 3 and the dozer check valve 6 and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump 3 to the dozer check valve 6 to release a check function of the dozer check valve 6 ;
  • a flow path 12 for floating connected at one end thereof to the hydraulic tank 7 and connected at the other end thereof to a flow path for connecting the control valve 5 to the dozer cylinder 4 ;
  • pilot check valve 11 installed in the flow path 12 for floating to open or close the flow path for floating, the pilot check valve being configured to be shifted to an open state by a pilot signal pressure supplied to the dozer check valve 6 to supply a hydraulic fluid from the hydraulic tank 7 to the dozer cylinder 4 through the flow path 12 for floating or to allow the hydraulic fluid discharged from the dozer cylinder 4 to be returned to the hydraulic tank 7 through the flow path 12 for floating in a floating mode, and shifted to a closed state by interruption of the supply of the pilot signal pressure to the dozer check valve 6 to block the flow path 12 for floating when the floating mode is released.
  • the flow path 12 for floating may be connected at the other end thereof to a large chamber of the dozer cylinder 4 .
  • the flow path 12 for floating may be connected at the other end thereof to a small chamber of the dozer cylinder 4 .
  • a configuration of the construction machine having a floating function in accordance with a second preferred embodiment of the present invention is the same as that of the construction machine having a floating function in accordance with the first embodiment of the present invention, except the pilot check valve 11 installed in the flow path 12 for floating and shifted to an open or closed state by the pilot signal pressure supplied to the dozer check valve 6 .
  • the pilot check valve 11 installed in the flow path 12 for floating and shifted to an open or closed state by the pilot signal pressure supplied to the dozer check valve 6 .
  • the dozer spool 5 a of the control valve 5 is maintained in a neutral state in the floating mode so that the hydraulic fluid from the hydraulic tank 7 can be supplied to the large chamber of the dozer cylinder 4 via the pilot check valve 11 installed in the flow path 12 for floating in a state in which the supply of the hydraulic fluid from the hydraulic pump 2 to the dozer cylinder 4 is interrupted. For this reason, it is possible to increase the downward movement speed or the descending speed of the dozer blade that is moved along the rugged ground surface in the floating mode.
  • the hydraulic fluid discharged from the dozer cylinder 4 by the drive of the piston of the dozer cylinder 4 can be promptly returned to the hydraulic tank 7 .
  • the pilot check valve 11 installed in the flow path 12 for floating is changed to an open state by the pilot signal pressure supplied to the dozer check valve 6 so that the hydraulic fluid discharged from the dozer cylinder 4 can be returned to the hydraulic tank 7 via the pilot check valve 11 upon the ascending of the dozer blade.
  • the hydraulic fluid discharged from the dozer cylinder 4 can be directly returned to the hydraulic tank 7 via the pilot check valve 11 without passing through the control valve 5 upon the ascending of the dozer blade.
  • the generation of the back pressure in the flow path can be minimized to increase the ascending speed of the dozer blade.
  • the hydraulic fluid discharged from the dozer cylinder 4 is returned to the hydraulic tank 7 via the control valve 5 , the dozer spool 5 a , and return check valve 8 in this order.
  • the back pressure is generated in the flow path, leading to a restriction of the ascending of the dozer blade.
  • the hydraulic fluid from the hydraulic tank 7 is replenished to the large chamber of the dozer cylinder 4 through the pilot check valve 11 installed in the flow path 12 for floating so that the downward movement speed or the descending speed of the dozer blade can be increased.
  • the hydraulic fluid discharged from the dozer cylinder 4 is promptly returned to the hydraulic tank 7 via the pilot check valve 11 so that the generation of the back pressure in the flow path along which the hydraulic fluid discharged from the dozer cylinder 4 is returned can be minimized to increase the ascending speed of the dozer blade.
  • FIG. 4 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a third preferred embodiment of the present invention.
  • the construction machine having a floating function includes a normal mode in which a dozer blade is moved vertically by the manipulation of a manipulation lever and a floating mode in which the dozer blade is moved vertically along a rugged ground surface by its own weight or an external force during the traveling of the construction machine.
  • the construction machine having a floating function in accordance with a third preferred embodiment of the present invention includes:
  • a hydraulic pump 2 and a pilot pump 3 which are connected to an engine 1 ;
  • a dozer cylinder 4 connected to the hydraulic pump and configured to move a dozer blade (not shown) upwardly and downwardly;
  • control valve 5 installed in a flow path between the hydraulic pump 2 and the dozer cylinder 4 and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder 4 ;
  • a dozer check valve 6 installed in a flow path between the control valve 5 and the dozer cylinder 4 ;
  • a return check valve 8 installed in a flow path between the control valve 5 and a hydraulic tank 7 ;
  • a solenoid valve 9 for floating openably/closably installed in a signal path 13 between the pilot pump 3 and the dozer check valve 6 and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump 3 to the dozer check valve 6 to release a check function of the dozer check valve 6 ;
  • a flow path 12 for floating connected at one end thereof to the hydraulic tank 7 and connected at the other end thereof to a flow path for connecting the control valve 5 to the dozer cylinder 4 ;
  • a 3-way valve installed at a crossing point of the flow path 12 for floating and the flow path on the control valve 5 side, the 3-way valve being configured to be shifted to a first position (I) by a pilot signal pressure supplied to the dozer check valve 6 to replenish a hydraulic fluid from the hydraulic tank 7 to the dozer cylinder 4 through the flow path 12 for floating in a floating mode and shifted to a second position (II), in which the supply of the pilot signal pressure to the dozer check valve 6 is interrupted to connect the flow path between the control valve 5 and the dozer cylinder 4 when the floating mode is released.
  • the flow path 12 for floating may be connected at the other end thereof to a large chamber of the dozer cylinder 4 .
  • a configuration of the construction machine having a floating function in accordance with a third preferred embodiment of the present invention is the same as that of the construction machine having a floating function in accordance with the first embodiment of the present invention, except the 3-way valve installed at the crossing point of the flow path 12 for floating and the flow path on the control valve 5 side and configured to replenish the hydraulic fluid from the hydraulic tank 7 to the dozer cylinder 4 in the floating mode, and the flow path 12 for floating connected at the other end thereof to a large chamber of the dozer cylinder 4 .
  • the detailed description of the same configuration and operation thereof will be omitted to avoid redundancy, and the same hydraulic parts are denoted by the same reference numerals.
  • the dozer spool 5 a of the control valve 5 is maintained in a neutral state in the floating mode so that the hydraulic fluid from the hydraulic tank 7 can be replenished to the dozer cylinder 4 by the shift of the 3-way valve 14 in a state in which the supply of the hydraulic fluid from the hydraulic pump 2 to the dozer cylinder 4 is interrupted.
  • a spool of the 3-way valve 14 is shifted to the bottom on the drawing sheet, i.e., is shifted to the first position (I).
  • the hydraulic fluid from the hydraulic tank 7 can be supplied to a large chamber of the dozer cylinder 4 via the flow path 12 for floating and the 3-way valve 14 .
  • the hydraulic fluid from the hydraulic tank 7 can be replenished to the large chamber of the dozer cylinder 4 via the flow path 12 for floating and the 3-way valve 14 upon the descending of the dozer blade so that the downward movement speed or the descending speed of the dozer blade that is moved along a rugged ground surface can be increased.
  • the supply of the pilot signal pressure to the dozer check valve 6 is interrupted and thus the supply of the pilot signal pressure to the 3-way valve 14 is also interrupted.
  • the 3-way valve 14 returns to its initial position by a valve spring thereof, i.e., the spool of the 3-way valve 14 is shifted to the second position (II).
  • the hydraulic fluid from the hydraulic tank 7 is replenished to the large chamber of the dozer cylinder 4 through the 3-way valve 13 via the flow path 12 for floating so that the downward movement speed or the descending speed of the dozer blade can be increased.
  • the dozer blade when the floating mode of the dozer blade is released, the dozer blade can be moved vertically by the hydraulic fluid supplied from the hydraulic pump 2 to the large chamber of the dozer cylinder 4 via the control valve 5 and the 3-way valve 14 .
  • FIG. 5 is a hydraulic circuit diagram of a construction machine having a floating function in accordance with a fourth preferred embodiment of the present invention.
  • the construction machine having a floating function includes a normal mode in which a dozer blade is moved vertically by the manipulation of a manipulation lever and a floating mode in which the dozer blade is moved vertically along a rugged ground surface by its own weight or an external force during the traveling of the construction machine.
  • the construction machine having a floating function in accordance with a fourth preferred embodiment of the present invention includes:
  • a hydraulic pump 2 and a pilot pump 3 which are connected to an engine 1 ;
  • a dozer cylinder 4 connected to the hydraulic pump and configured to move a dozer blade (not shown) upwardly and downwardly;
  • control valve 5 installed in a flow path between the hydraulic pump 2 and the dozer cylinder 4 and configured to be shifted to control a start, a stop, and a direction change of the dozer cylinder 4 ;
  • a dozer check valve 6 installed in a flow path between the control valve 5 and the dozer cylinder 4 ;
  • a return check valve 8 installed in a flow path between the control valve 5 and a hydraulic tank 7 ;
  • a solenoid valve 9 for floating openably/closably installed in a signal path 13 between the pilot pump 3 and the dozer check valve 6 and configured to be shifted to an open state to supply a pilot signal pressure from the pilot pump 3 to the dozer check valve 6 to release a check function of the dozer check valve 6 ;
  • a flow path 12 for floating connected at one end thereof to the hydraulic tank 7 and connected at the other end thereof to a flow path for connecting the control valve 5 to the dozer cylinder 4 ;
  • a 3-way valve 15 installed at a crossing point of the flow path 12 for floating and the flow path on the control valve 5 side, the 3-way valve being configured to be shifted to a first position (I) by a pilot signal pressure supplied to the dozer check valve 6 to allow the dozer cylinder 4 , the control valve 5 , and the hydraulic tank 7 to fluidically communicate with one another in a floating mode and shifted to a second position in which the supply of the pilot signal pressure to the dozer check valve 6 is interrupted to connect the flow path between the control valve 5 and the dozer cylinder 4 when the floating mode is released.
  • the flow path 12 for floating may be connected at the other end thereof to a large chamber of the dozer cylinder 4 .
  • the flow path 12 for floating may be connected at the other end thereof to a small chamber of the dozer cylinder 4 .
  • a configuration of the construction machine having a floating function in accordance with a fourth preferred embodiment of the present invention is the same as that of the construction machine having a floating function in accordance with the third embodiment of the present invention, except the 3-way valve installed at a crossing point of the flow path 12 for floating and the flow path on the control valve 5 side and configured to be shifted to allow the dozer cylinder 4 , the control valve 5 , and the hydraulic tank 7 to fluidically communicate with one another in a floating mode and to supply the hydraulic fluid from the hydraulic pump 2 to the dozer cylinder 4 when the floating mode is released, and the flow path 12 for floating connected at the other end thereof to a large or small chamber of the dozer cylinder 4 .
  • the detailed description of the same configuration and operation thereof will be omitted to avoid redundancy, and the same hydraulic parts are denoted by the same reference numerals.
  • the dozer spool 5 a of the control valve 5 is maintained in a neutral state in the floating mode so that the hydraulic fluid from the hydraulic tank 7 can be replenished to the dozer cylinder 4 by the shift of the 3-way valve 15 in a state in which the supply of the hydraulic fluid from the hydraulic pump 2 to the large chamber of the dozer cylinder 4 is interrupted.
  • a spool of the 3-way valve 15 is shifted to the bottom on the drawing sheet, i.e., is shifted to the first position (I).
  • the hydraulic fluid from the hydraulic tank 7 can be supplied to the large chamber of the dozer cylinder 4 via the flow path 12 for floating and the 3-way valve 15 .
  • the hydraulic fluid from the hydraulic tank 7 can be replenished to the large chamber of the dozer cylinder 4 via the flow path 12 for floating and the 3-way valve 15 upon the descending of the dozer blade so that the downward movement speed or the descending speed of the dozer blade that is moved along a rugged ground surface can be increased.
  • the hydraulic fluid discharged from the dozer cylinder 4 by the drive of the piston of the dozer cylinder 4 can be promptly returned to the hydraulic tank 7 .
  • a spool of the 3-way valve 15 is shifted to the first position (I) by the pilot signal pressure supplied to the dozer check valve 6 so that the hydraulic fluid discharged from the large chamber of the dozer cylinder 4 can be returned to the hydraulic tank 7 via the 3-way valve 15 upon the ascending of the dozer blade.
  • the hydraulic fluid discharged from the dozer cylinder 4 can be directly returned to the hydraulic tank 7 via the 3-way valve 15 without passing through the control valve 5 upon the ascending of the dozer blade.
  • the generation of the back pressure in the flow path can be minimized to increase the ascending speed of the dozer blade.
  • the 3-way valve 15 returns to its initial position by a valve spring thereof, i.e., the spool of the 3-way valve 15 is shifted to the second position (II)(see a state shown in FIG. 5 ).
  • the hydraulic fluid from the hydraulic tank 7 is replenished to the large chamber of the dozer cylinder 4 through the 3-way valve 15 via the flow path 12 for floating so that the downward movement speed or the descending speed of the dozer blade can be increased.
  • the hydraulic fluid discharged from the dozer cylinder 4 can be promptly returned to the hydraulic tank 7 without passing through the control valve 5 so that the generation of the back pressure in the flow path along which the hydraulic fluid discharged from the dozer cylinder 4 is returned to the hydraulic tank can be minimized to increase the ascending speed of the dozer blade.
  • the floating mode of the dozer blade is released, the dozer blade can be moved vertically by the hydraulic fluid supplied from the hydraulic pump 2 to the dozer cylinder 4 via the control valve 5 and the 3-way valve 15 .
  • the construction machine having a floating function in accordance with the present invention as constructed above has an effect in that when a ground leveling work or a grading work is performed by the floating function of the dozer blade, the vertical movement speed of the dozer blade can be increased, thereby improving workability.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Operation Control Of Excavators (AREA)
US14/652,012 2012-12-20 2012-12-20 Construction machine with floating function Abandoned US20150315768A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/KR2012/011178 WO2014098284A1 (ko) 2012-12-20 2012-12-20 플로팅 기능이 구비된 건설기계

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US (1) US20150315768A1 (ko)
EP (1) EP2937472A4 (ko)
KR (1) KR101741702B1 (ko)
AU (1) AU2012397386B2 (ko)
WO (1) WO2014098284A1 (ko)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150322648A1 (en) * 2013-01-24 2015-11-12 Volvo Construction Equipment Ab Device and method for controlling flow rate in construction machinery
US10407876B2 (en) 2015-06-02 2019-09-10 Doosan Infracore Co., Ltd. Hydraulic system of construction machinery
US10900562B2 (en) * 2015-12-07 2021-01-26 Kubota Corporation Hydraulic system of work machine and work machine
CN113323071A (zh) * 2021-05-14 2021-08-31 安徽铜冠机械股份有限公司 地下铲运机铲斗浮动控制单元

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102491222B1 (ko) * 2015-12-11 2023-01-25 주식회사 대동 작업차용 작업기 승강 및 플로팅 구현을 위한 유압회로
CN110158682B (zh) * 2019-05-06 2021-07-02 广西柳工机械股份有限公司 平地机工作装置液压系统

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4282798A (en) * 1979-10-22 1981-08-11 Ex-Cell-O Corporation Control valve unit for hydraulic linear actuator
US4359931A (en) * 1981-01-19 1982-11-23 The Warner & Swasey Company Regenerative and anticavitation hydraulic system for an excavator
US6092454A (en) * 1998-07-23 2000-07-25 Caterpillar Inc. Controlled float circuit for an actuator

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4166506A (en) * 1975-06-30 1979-09-04 Kabushiki Kaisha Komatsu Seisakusho Controlling apparatus for bulldozer blade
JP3478931B2 (ja) * 1996-09-20 2003-12-15 新キャタピラー三菱株式会社 油圧回路
JP2002088796A (ja) * 2000-09-19 2002-03-27 Kobelco Contstruction Machinery Ltd ドーザ装置
US6892535B2 (en) * 2002-06-14 2005-05-17 Volvo Construction Equipment Holding Sweden Ab Hydraulic circuit for boom cylinder combination having float function
DE10307346A1 (de) * 2003-02-21 2004-09-02 Deere & Company, Moline Ventilanordnung
CN101225845A (zh) * 2006-11-14 2008-07-23 胡斯可国际股份有限公司 用于液压系统的能量回收与再利用方法
KR100849500B1 (ko) * 2006-11-29 2008-07-31 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 플로팅 기능이 구비된 더블 체크밸브
KR101500744B1 (ko) * 2008-11-19 2015-03-09 두산인프라코어 주식회사 건설기계의 붐 실린더 제어회로

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4282798A (en) * 1979-10-22 1981-08-11 Ex-Cell-O Corporation Control valve unit for hydraulic linear actuator
US4359931A (en) * 1981-01-19 1982-11-23 The Warner & Swasey Company Regenerative and anticavitation hydraulic system for an excavator
US6092454A (en) * 1998-07-23 2000-07-25 Caterpillar Inc. Controlled float circuit for an actuator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150322648A1 (en) * 2013-01-24 2015-11-12 Volvo Construction Equipment Ab Device and method for controlling flow rate in construction machinery
US9725882B2 (en) * 2013-01-24 2017-08-08 Volvo Construction Equipment Ab Device and method for controlling flow rate in construction machinery
US10407876B2 (en) 2015-06-02 2019-09-10 Doosan Infracore Co., Ltd. Hydraulic system of construction machinery
US10900562B2 (en) * 2015-12-07 2021-01-26 Kubota Corporation Hydraulic system of work machine and work machine
US11644098B2 (en) 2015-12-07 2023-05-09 Kubota Corporation Hydraulic system of work machine and work machine
CN113323071A (zh) * 2021-05-14 2021-08-31 安徽铜冠机械股份有限公司 地下铲运机铲斗浮动控制单元

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WO2014098284A1 (ko) 2014-06-26
KR101741702B1 (ko) 2017-05-30
AU2012397386B2 (en) 2016-05-19
EP2937472A1 (en) 2015-10-28
KR20150092168A (ko) 2015-08-12
EP2937472A4 (en) 2016-09-07
AU2012397386A1 (en) 2015-07-09

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