US20160122980A1 - Construction machine energy regeneration apparatus - Google Patents
Construction machine energy regeneration apparatus Download PDFInfo
- Publication number
- US20160122980A1 US20160122980A1 US14/895,081 US201414895081A US2016122980A1 US 20160122980 A1 US20160122980 A1 US 20160122980A1 US 201414895081 A US201414895081 A US 201414895081A US 2016122980 A1 US2016122980 A1 US 2016122980A1
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- United States
- Prior art keywords
- movable weight
- construction machine
- operating part
- hydraulic
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- 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
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/14—Energy-recuperation means
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- 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
- E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
-
- 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
- E02F9/18—Counterweights
-
- 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
-
- 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
- E02F9/2296—Systems with a variable displacement pump
-
- 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
- E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
- E02F3/30—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom
- E02F3/32—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom working downwardly and towards the machine, e.g. with backhoes
Definitions
- the present invention relates to a construction machine energy regeneration apparatus included in a construction machine that includes an operating part including a boom, a turning unit, or a running unit driven by a drive unit.
- a hydraulic excavator that causes an electric motor to regenerate electric power when, for example, reducing the speed of a turning unit, stores the regenerative electric power in a capacitor, uses the regenerative electric power stored in the capacitor to operate the electric motor via a controller and an inverter when turning the turning unit, and assists the rotation of a hydraulic motor with the torque of the electric motor (see Patent Literature 1, for example).
- the fuel consumption can be reduced.
- the above-described conventional hydraulic excavator needs to include the capacitor and the inverter as equipment for storing the regenerative electric power and utilizing the stored regenerative electric power when turning the turning unit. This causes an increase in cost, a high possibility of the occurrence of a failure, and in addition, size and weight increase.
- the above-described conventional hydraulic excavator goes through multiple steps including: converting mechanical energy of the turning unit into electrical energy; temporarily storing the electrical energy; and then converting the electrical energy into mechanical energy again. Therefore, the overall energy regenerative ratio is not very high, which is another problem.
- the above-described conventional hydraulic excavator is unable to regenerate potential energy when the hydraulic excavator is in a motion different from turning (i.e., boom lowering, arm crowding, or bucket crowding).
- An object of the present invention is to provide a construction machine energy regeneration apparatus and a construction machine including the same, which make it possible to eliminate the capacitor and the inverter, thereby reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in weight.
- a construction machine energy regeneration apparatus is an 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 includes: 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.
- the movable weight can be moved (e.g., swung) upward by utilizing energy that is generated when the boom or the like moves in the gravitational direction or energy that is generated when a brake is applied to bring the turning unit or the like to a stop.
- This makes it possible to store the potential energy of the boom or the like or the kinetic energy of the turning unit or the like as the potential energy of the movable weight.
- the boom, the turning unit, or the like can be driven by utilizing the potential energy of the movable weight.
- the potential energy of the boom or the like or the kinetic energy of the turning unit or the like can be stored as the potential energy of the movable weight and utilized as described above, the fuel consumption of the construction machine can be reduced compared to conventional art.
- the construction machine energy regeneration apparatus may include: 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.
- the switching valve may be configured to shift 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 may be configured to shift 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.
- the switching valve which switches the flow direction of the hydraulic fluid in the communication passage, is provided on the communication passage, through which the circuit of the first operating part or the circuit of the second operating part communicates with the circuit of the movable weight. Therefore, potential energy or kinetic energy of the first operating part or the second operating part can be regenerated, and the regenerative energy can be utilized for driving the first operating part or the second operating part.
- the construction machine energy regeneration apparatus may be configured such that the movable weight and a part of the power-transmitting hydraulic circuit have a function as a counter weight of the construction machine, and such that 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.
- the total mass of the hydraulic excavator can be made not to exceed the total mass of the hydraulic excavator that does not include the energy regeneration apparatus. This makes it possible to prevent an increase in power for operating the turning unit or the running unit, which is an operating part, as well as an increase in fuel consumption. Consequently, energy can be regenerated and utilized more effectively.
- the movable weight may be supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder.
- the moving distance of the center of gravity of the movable weight in the vertical direction can be made relatively great, and in addition, the stroke of the hydraulic cylinder for vertically swinging the movable weight by a predetermined angle can be set to be relatively small.
- the movable weight may be configured to be movable in a linear direction.
- the movable weight may be supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder.
- the hydraulic cylinder may include 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 may be 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 may be configured to operate 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 may be configured to operate the assisting cylinder when the movable weight swings downward to drive the first operating part or the second operating part.
- the distance between the fulcrum and the connection where the lifting cylinder is connected to the movable weight is set to be greater than the distance between the fulcrum and the connection where the assisting cylinder is connected to the movable weight. Accordingly, the pressure discharged from the assisting cylinder to lower the movable weight can be made higher than the pressure supplied to the lifting cylinder to raise the movable weight. Therefore, the pressure of the hydraulic fluid for driving the first operating part or the second operating part can be made high, which makes it possible to widen a pressure range within which the potential energy of the movable weight is utilized.
- the construction machine energy regeneration apparatus may include: 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.
- the controller performs control of opening the switching valve via the solenoid pilot valve. This makes it possible to efficiently regenerate the potential energy or kinetic energy of the boom, the turning unit, or the like as the potential energy of the movable weight.
- the construction machine energy regeneration apparatus is configured to regenerate the potential energy of an operating part or kinetic energy based on inertial force, and utilize the regenerative energy for driving an operating part. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art.
- the construction machine energy regeneration apparatus makes it possible to eliminate, for example, a capacitor and an inverter for regenerating the potential energy of an operating part or kinetic energy based on inertial force, thereby reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in the weight of the construction machine
- FIG. 1 is a side view showing a hydraulic excavator including a construction machine energy regeneration apparatus according to Embodiment 1 of the present invention.
- FIG. 2 is a schematic diagram showing, in an exaggerated manner, a movable weight of the construction machine energy regeneration apparatus of FIG. 1 .
- FIG. 3 shows a hydraulic circuit of the hydraulic excavator of FIG. 1 .
- FIG. 4 shows a control circuit of a weight switching valve of FIG. 3 .
- FIG. 5 shows the state of the hydraulic circuit of the hydraulic excavator of FIG. 3 at the time of boom raising.
- FIG. 6 shows the state of the hydraulic circuit of the hydraulic excavator of FIG. 3 when energy is regenerated at the time of boom lowering.
- FIG. 7 shows the state of the hydraulic circuit of the hydraulic excavator of FIG. 3 when regenerative energy is utilized for arm pushing.
- FIG. 8 shows a hydraulic circuit of a hydraulic excavator according to Embodiment 2 in a state where regenerative energy is utilized for bucket pushing.
- FIG. 9 shows a hydraulic circuit of a hydraulic excavator according to Embodiment 3 in a state where regenerative energy is utilized for operating an engine-assisting hydraulic motor and arm pushing.
- FIG. 10 shows a hydraulic circuit of a hydraulic excavator according to Embodiment 4 in a state where energy is regenerated when a brake is applied to bring a turning unit to a stop.
- FIG. 11 shows the state of the hydraulic circuit of the hydraulic excavator of FIG. 10 when regenerative energy is utilized for arm pushing.
- FIG. 12 is a schematic diagram showing, in an exaggerated manner, a movable weight of a construction machine energy regeneration apparatus according to Embodiment 5.
- FIG. 13 is a schematic diagram showing, in an exaggerated manner, a movable weight of a construction machine energy regeneration apparatus according to Embodiment 6.
- a construction machine energy regeneration apparatus 11 is included in a construction machine such as a hydraulic excavator 15 , whose operating part includes, for example, a boom 12 , a turning unit 13 , and a running unit 14 shown in FIG. 1 and FIG. 2 and is driven by a hydraulic fluid discharged from a hydraulic pump 28 (drive unit) shown in FIG. 3 .
- the construction machine energy regeneration apparatus 11 includes a movable weight 16 movable vertically and a power-transmitting hydraulic circuit 17 A (see FIG. 3 ).
- the boom 12 , the turning unit 13 , or the running unit 14 is referred to as a first operating part, and an arm 19 , a bucket 20 , or an engine-assisting hydraulic motor 52 (see FIG. 9 ) is referred to as a second operating part.
- the power-transmitting hydraulic circuit 17 A shown in FIG. 3 is configured to move the movable weight 16 upward by utilizing, for example, energy that is generated when the boom 12 , the arm 19 , or the bucket 20 moves in the gravitational direction or energy that is generated when a brake is applied to bring the turning unit 13 or the running unit 14 to a stop, and utilize the potential energy of the movable weight 16 as energy for driving the first operating part such as the boom 12 or the second operating part such as the arm 19 .
- the turning unit 13 is turnably mounted on the running unit 14 via a turning mechanism 18 .
- the boom 12 is mounted to the front central part of the turning unit 13 , such that the boom 12 is swingable up and down.
- the arm 19 is mounted to the distal end of the boom 12 , such that the arm 19 is rotatable in a vertical plane.
- the bucket 20 is mounted to the distal end of the arm 19 , such that the bucket 20 is rotatable in a vertical plane.
- FIG. 2 is a schematic diagram showing, in an exaggerated manner, the movable weight 16 , which is provided at the rear of the turning unit 13 of the hydraulic excavator 15 .
- the movable weight 16 has a function of storing the gravitational force of the boom 12 or the like as potential energy, and has a function as a counter weight of the hydraulic excavator 15 .
- the movable weight 16 and a part of the power-transmitting hydraulic circuit 17 A have a function as a counter weight of the hydraulic excavator 15 , and the total mass of the movable weight 16 and the part of the power-transmitting hydraulic circuit 17 A is set to be substantially equal to the mass of a counter weight required by the hydraulic excavator 15 .
- the shape and the material of the movable weight 16 shown in FIG. 2 are equivalent to those of a conventional counter weight.
- the movable weight 16 is provided at the rear of the turning unit 13 , and is positioned at the opposite side to the boom 12 with respect to the turning mechanism 18 .
- the movable weight 16 is provided such that the movable weight 16 is movable vertically in a linear direction along guides 25 .
- a weight hydraulic cylinder 21 is provided under the movable weight 16 .
- the weight hydraulic cylinder 21 supports the movable weight 16 such that the movable weight 16 is movable vertically in the linear direction.
- the weight hydraulic cylinder 21 is provided between the lower part of the movable weight 16 and a frame 13 a of the turning unit 13 .
- the weight hydraulic cylinder 21 includes: a cylinder portion 21 a whose proximal end is fixed to the frame 13 a of the turning unit 13 ; and a piston rod 21 b whose distal end is swingably connected to the lower part of the movable weight 16 via a connection 26 .
- FIG. 3 shows a hydraulic circuit 27 including the power-transmitting hydraulic circuit 17 A of the hydraulic excavator 15 .
- the hydraulic circuit 27 includes communication passages 22 ( 22 a, 22 b, and 22 c ) and a weight switching valve 24 . It should be noted that, in FIG. 3 , circuits other than those of the boom 12 and the arm 19 are omitted.
- the communication passages 22 are passages through which the circuits of the first operating part and the second operating part, including boom communication passages 53 ( 53 a and 53 b ) and arm communication passages 54 ( 54 a and 54 b ), communicate with movable weight communication passages 55 ( 55 a and 55 b ).
- the weight switching valve 24 is connected to the communication passages 22 , and serves to switch the flow direction of the hydraulic fluid in the communication passages 22 .
- the weight switching valve 24 shifts to a first position (II) when the boom 12 , the arm 19 , or the bucket 20 moves in the gravitational direction or when a brake is applied to bring the turning unit 13 or the running unit 14 to a stop, such that the hydraulic fluid flows through the communication passages 22 and the weight switching valve 24 , and thereby the movable weight 16 can be moved upward.
- the weight switching valve 24 shifts to a second position (III) when the movable weight 16 moves in the gravitational direction, such that the hydraulic fluid flows through the communication passages 22 and the weight switching valve 24 , and thereby the first operating part including the boom 12 or the second operating part including the arm 19 can be driven.
- ports A and B of the weight switching valve 24 shown in FIG. 3 are connected to a head-side port of the weight hydraulic cylinder 21 and a rod-side port of the weight hydraulic cylinder 21 via the movable weight communication passages 55 a and 55 b .
- Ports B and C of the weight switching valve 24 are connected to each other.
- a port T of the weight switching valve 24 is connected to a tank 32
- a port P of the weight switching valve 24 is connected to a discharge port of the hydraulic pump 28 via the communication passage 22 .
- a port D of the weight switching valve 24 is connected to the arm communication passage 54 a via the communication passage 22 a.
- the communication passage 22 a is provided with a check valve.
- the hydraulic circuit 27 shown in FIG. 3 includes control valves for the first operating part including the boom 12 and control valves for the second operating part including the arm 19 . Each of these control valves serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to the first operating part or the second operating part.
- FIG. 3 shows an arm control valve 56 and a boom control valve 57 .
- the arm control valve 56 serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to an arm hydraulic cylinder 37 .
- Ports A and B of the arm control valve 56 are connected to two ports (rod-side and head-side ports) of the arm hydraulic cylinder 37 via the arm communication passages 54 a and 54 b.
- a port T of the arm control valve 56 is connected to the tank 32 via a tank communication passage 60
- a port P of the arm control valve 56 is connected to the discharge port of the hydraulic pump 28 via a pump communication passage 61 .
- the boom control valve 57 serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to a boom hydraulic cylinder 39 .
- Ports A and B of the boom control valve 57 are connected to two ports (rod-side and head-side ports) of the boom hydraulic cylinder 39 via the boom communication passages 53 a and 53 b.
- a port T of the boom control valve 57 is connected to the tank 32 via a tank communication passage 62
- a port P of the boom control valve 57 is connected to the discharge port of the hydraulic pump 28 via a pump communication passage 63 .
- FIG. 3 shows remote control valves, each of which serves to supply a pilot pressure liquid to pilot ports of a corresponding one of the above control valves.
- FIG. 3 shows an arm remote control valve 64 and a boom remote control valve 65 .
- the arm remote control valve 64 is operated by an operator and serves to supply the pilot pressure liquid to pilot ports X and Y of the arm control valve 56 through communication passages 64 b and 64 a.
- the boom remote control valve 65 is operated by the operator and serves to supply the pilot pressure liquid to pilot ports X and Y of the boom control valve 57 through communication passage 65 b and 65 a.
- First to tenth pressure sensors PS 1 to PS 10 serve to: measure a supply pressure and a discharge pressure of the hydraulic fluid of the first operating part or the second operating part; measure output pressures of the remote control valves; and generate pressure signals as electrical signals.
- FIG. 3 shows first to sixth pressure sensors PS 1 to PS 6 .
- the first and second pressure sensors PS 1 and PS 2 serve to measure output pressures of the boom remote control valve 65 , which occur in the communication passages 65 a and 65 b , and generate pressure signals as electrical signals.
- the third and fourth pressure sensors PS 3 and PS 4 serve to measure output pressures of the arm remote control valve 64 , which occur in the communication passages 64 a and 64 b , and generate pressure signals as electrical signals.
- the fifth and sixth pressure sensors PS 5 and PS 6 serve to measure output pressures that occur in the boom communication passages 53 b and 53 a, which are connected to the boom hydraulic cylinder 39 , and generate pressure signals as electrical signals.
- the hydraulic circuit 27 shown in FIG. 3 further includes a control circuit 70 shown in FIG. 4 .
- the control circuit 70 shown in FIG. 4 includes first and second solenoid pilot valves 71 and 72 and a controller 73 .
- the first solenoid pilot valve 71 shown in FIG. 4 serves to supply a pilot pressure liquid to a pilot port Pia of the weight switching valve 24 shown in FIG. 3 in accordance with a current flowing through a first signal line 71 a .
- the pressure source of the pilot pressure liquid is a hydraulic pressure discharged from a control hydraulic pump 74 .
- the second solenoid pilot valve 72 serves to supply a pilot pressure liquid to a pilot port Pib of the weight switching valve 24 shown in FIG. 3 in accordance with a current flowing through a second signal line 72 a.
- the pressure source of the pilot pressure liquid is a hydraulic pressure discharged from the control hydraulic pump 74 .
- the controller 73 serves to electrically receive electrical pressure signals outputted from the first to tenth pressure sensors PS 1 to PS 10 , and transmit electrical command signals to the first and second solenoid pilot valves 71 and 72 based on the electrical pressure signals.
- FIG. 5 shows the state of the hydraulic circuit 27 and the control circuit 70 of FIG. 3 and FIG. 4 of the hydraulic excavator 15 at the time of raising of the boom 12 .
- the spool of the boom control valve 57 shifts to the position (III), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the boom hydraulic cylinder 39 as indicated by a bold solid line, and thereby the boom 12 can be raised to a desired height.
- the pressurized oil discharged from the hydraulic pump 28 is supplied also to the weight switching valve 24 .
- the port P is closed at the time, the pressurized oil is not supplied to the weight hydraulic cylinder 21 . Accordingly, the movable weight 16 remains stopped without being raised or lowered.
- FIG. 6 shows the state of the hydraulic circuit 27 and the control circuit 70 of FIG. 3 and FIG. 4 when energy is regenerated at the time of lowering of the boom 12 .
- the spool of the boom control valve 57 shifts to the position (II), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the boom hydraulic cylinder 39 as indicated by a bold solid line, and thereby the boom 12 can be lowered to a desired height.
- pressurized oil discharged from the boom hydraulic cylinder 39 is supplied to the weight switching valve 24 .
- the controller 73 electrically receives electrical pressure signals outputted from the fifth and sixth pressure sensors PS 5 and PS 6 , and transmits an electrical command signal to the second solenoid pilot valve 72 based on the electrical pressure signals.
- the spool of the weight switching valve 24 shifts to the position (II), such that pressurized oil discharged from the boom hydraulic cylinder 39 is, as indicated by a bold one-dot chain line, supplied to the weight hydraulic cylinder 21 through the weight switching valve 24 , and thereby the movable weight 16 can be raised.
- the controller 73 performs control of opening the weight switching valve 24 via the second solenoid pilot valve 72 . This makes it possible to efficiently regenerate the potential energy of the boom 12 as the potential energy of the movable weight 16 .
- FIG. 6 illustrates an example in which the potential energy of the boom 12 is regenerated as the potential energy of the movable weight 16 .
- the potential energy of the arm 19 , the bucket 20 , or the like can be regenerated as the potential energy of the movable weight 16 although it is not shown in the drawings.
- FIG. 7 shows the state of the hydraulic circuit 27 and the control circuit 70 of FIG. 3 and FIG. 4 when regenerative energy is utilized for pushing of the arm 19 .
- the spool of the arm control valve 56 shifts to the position (II), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the arm hydraulic cylinder 37 as indicated by a bold solid line and a bold one-dot chain line, and thereby the arm 19 can be swung in the pushing direction.
- the controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the arm hydraulic cylinder 37 , and transmits an electrical command signal to the first solenoid pilot valve 71 based on the electrical pressure signals.
- the spool of the weight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weight hydraulic cylinder 21 is supplied to the arm hydraulic cylinder 37 through the weight switching valve 24 as indicated by a bold one-dot chain line, and thereby the arm 19 can be swung in the pushing direction. In this manner, regenerative energy can be utilized for pushing of the arm 19 .
- the movable weight 16 can be moved upward by utilizing energy that is generated when the boom 12 moves in the gravitational direction (i.e., when the boom 12 is lowered). In this manner, the potential energy of the boom 12 can be stored as the potential energy of the movable weight 16 .
- the potential energy of the movable weight 16 can be utilized to drive the arm 19 in the pushing direction.
- the potential energy of the boom 12 can be stored as the potential energy of the movable weight 16 and utilized as described above. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art.
- the movable weight 16 has a function as a counter weight of such a construction machine as the hydraulic excavator 15 .
- the total mass of the movable weight 16 and a part of the power-transmitting hydraulic circuit 17 A ( 17 B and 17 C in Embodiments 3 and 4 described below) is set to be substantially equal to the mass of a counter weight required by the construction machine.
- the total mass of the hydraulic excavator 15 can be made not to exceed the total mass of the hydraulic excavator 15 that does not include the energy regeneration apparatus 11 .
- the movable weight 16 is provided such that the movable weight 16 is movable in a linear direction. This makes it possible to provide an inexpensive construction machine energy regeneration apparatus 11 with a simple structure and reduced failures.
- FIG. 8 shows a hydraulic circuit of Embodiment 2 of the present invention in a state where regenerative energy is utilized for driving the bucket 20 .
- a bucket control valve 58 serves to control the pressure and the flow rate of a hydraulic fluid supplied to a bucket hydraulic cylinder 38 . Similar to the above-described configuration, the bucket control valve 58 is connected to the bucket hydraulic cylinder 38 , the tank 32 , and the hydraulic pump 28 .
- a bucket remote control valve 66 is connected to pilot ports X and Y of the bucket control valve 58 via communication passages 66 b and 66 a.
- the seventh and eighth pressure sensors PS 7 and PS 8 shown in FIG. 8 serve to measure output pressures of the bucket remote control valve 66 , which occur in the communication passages 66 a and 66 b, and generate pressure signals as electrical signals.
- FIG. 8 shows the state of the hydraulic circuit 27 and the control circuit 70 of FIG. 3 and FIG. 4 when regenerative energy is utilized for pushing of the bucket 20 .
- the state shown in FIG. 8 is different from the state shown in FIG. 7 in the following point: in the state shown in FIG. 7 , regenerative energy is utilized for pushing of the arm 19 , whereas in the state shown in FIG. 8 , regenerative energy is utilized for pushing of the bucket 20 .
- the spool of the bucket control valve 58 shifts to the position (II), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the bucket hydraulic cylinder 38 as indicated by a bold solid line and a bold one-dot chain line, and thereby the bucket 20 can be swung in the pushing direction.
- the controller 73 operates in the same manner as in the case shown in FIG. 7 , such that pressurized oil discharged from the weight hydraulic cylinder 21 is supplied to the bucket hydraulic cylinder 38 through the weight switching valve 24 as indicated by a bold one-dot chain line, and thereby the bucket 20 can be swung in the pushing direction.
- regenerative energy i.e., potential energy of the movable weight 16
- FIG. 9 shows a hydraulic circuit 75 of Embodiment 3.
- the hydraulic circuit 75 includes the power-transmitting hydraulic circuit 17 B of the hydraulic excavator 15 , and is configured such that the communication passage 22 a for the engine-assisting hydraulic motor 52 is added to the hydraulic circuit 27 shown in FIG. 3 .
- FIG. 9 shows a state where the engine-assisting hydraulic motor 52 is driven by regenerative energy, and regenerative energy is utilized for pushing of the arm 19 .
- the spool of the arm control valve 56 shifts to the position (II), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the arm hydraulic cylinder 37 as indicated by a bold solid line, and thereby the arm 19 can be swung in the pushing direction.
- the controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the arm hydraulic cylinder 37 , and transmits an electrical command signal to the first solenoid pilot valve 71 based on the electrical pressure signals.
- the spool of the weight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weight hydraulic cylinder 21 is supplied to the engine-assisting hydraulic motor 52 through the weight switching valve 24 and the communication passage 22 a as indicated by a bold one-dot chain line.
- the engine-assisting hydraulic motor 52 rotates, and thereby driving of the hydraulic pump 28 , which is connected to the rotary shaft of the engine-assisting hydraulic motor 52 , can be assisted.
- the port D of the weight switching valve 24 is connected to the oil inlet of the engine-assisting hydraulic motor 52 via the communication passage 22 a.
- FIG. 10 shows a hydraulic circuit 76 of Embodiment 4.
- the hydraulic circuit 76 includes the power-transmitting hydraulic circuit 17 C of the hydraulic excavator 15 , and is configured such that turning unit communication passages 69 a and 69 b are added to the hydraulic circuit 27 shown in FIG. 3 instead of the boom communication passages 53 a and 53 b, and also, check valves 78 a and 78 b, which guide oil flowing out of the turning unit communication passages 69 a and 69 b in one direction, are added.
- FIG. 10 shows a turning unit control valve 59 .
- the turning unit control valve 59 serves to control the pressure and the flow rate of a hydraulic fluid supplied to a turning unit hydraulic motor 36 . Similar to the configuration previously described, the turning unit control valve 59 is connected to the turning unit hydraulic motor 36 , the tank 32 , and the hydraulic pump 28 .
- a turning unit remote control valve 67 is connected to pilot ports X and Y of the turning unit control valve 59 via communication passages 67 b and 67 a.
- the ninth and tenth pressure sensors PS 9 and PS 10 shown in FIG. 10 serve to measure output pressures of the turning unit remote control valve 67 , which occur in the communication passages 67 a and 67 b, and generate pressure signals as electrical signals.
- FIG. 10 shows a state where energy is regenerated when a brake is applied to bring the turning unit 13 to a stop.
- the operator operates the turning unit remote control valve 67 in order to apply a brake to bring the turning unit 13 to a stop while the turning unit 13 is turning in a reverse direction.
- the spool of the turning unit control valve 59 shifts from the position (II) to position (I), such that the outlet side of the turning unit hydraulic motor 36 is blocked by the turning unit control valve 59 .
- the controller 73 electrically receives electrical pressure signals outputted from the ninth and tenth pressure sensors PS 9 and PS 10 , and transmits an electrical command signal to the second solenoid pilot valve 72 based on the electrical pressure signals.
- the spool of the weight switching valve 24 shifts to the position II, such that pressurized oil discharged from the turning unit hydraulic motor 36 is supplied to the weight hydraulic cylinder 21 through the weight switching valve 24 as indicated by a bold one-dot chain line, and thereby the movable weight 16 can be raised. It should be noted that, at the time, the turning unit hydraulic motor 36 sucks the pressurized oil from the tank 32 .
- the controller 73 performs control of opening the weight switching valve 24 via the second solenoid pilot valve 72 . This makes it possible to efficiently regenerate the kinetic energy of the turning unit 13 as the potential energy of the movable weight 16 .
- FIG. 10 illustrates an example in which the kinetic energy of the turning unit 13 is regenerated as the potential energy of the movable weight 16 .
- the kinetic energy of the running unit 14 can be regenerated as the potential energy of the movable weight 16 although it is not shown in the drawings.
- the port P of the weight switching valve 24 is connected to the oil inlet port and the oil outlet port of the turning unit hydraulic motor 36 via a communication passage 36 a.
- the reference sign 77 in FIG. 10 indicates relief valves for controlling the discharge pressure of the hydraulic pump 28 .
- FIG. 11 shows the state of the hydraulic circuit 76 of the hydraulic excavator 15 of FIG. 10 when regenerative energy is utilized for pushing of the arm 19 .
- the spool of the arm control valve 56 shifts to the position (II), such that pressurized oil discharged from the hydraulic pump 28 is supplied to the arm hydraulic cylinder 37 as indicated by a bold solid line and a bold one-dot chain line, and thereby the arm 19 can be swung in the pushing direction.
- the controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the arm hydraulic cylinder 37 , and transmits an electrical command signal to the first solenoid pilot valve 71 based on the electrical pressure signals.
- the spool of the weight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weight hydraulic cylinder 21 is supplied to the arm hydraulic cylinder 37 through the weight switching valve 24 and the communication passages 22 a and 54 a as indicated by a bold one-dot chain line, and thereby the arm 19 can be swung in the pushing direction. In this manner, the driving of the hydraulic pump 28 can be assisted.
- regenerative energy potential energy of the movable weight 16
- regenerative energy can be utilized for pushing of the arm 19 .
- the movable weight 16 can be moved upward. In this manner, the kinetic energy of the turning unit 13 can be stored as the potential energy of the movable weight 16 .
- the arm 19 can be driven by utilizing the potential energy of the movable weight 16 .
- the kinetic energy of the turning unit 13 can be stored as the potential energy of the movable weight 16 and utilized as described above. This makes it possible to reduce the fuel consumption of a construction machine compared to conventional art.
- Embodiment 5 of the construction machine energy regeneration apparatus according to the present invention is described with reference to FIG. 12 .
- a construction machine energy regeneration apparatus 43 according to Embodiment 2 shown in FIG. 12 is different from the construction machine energy regeneration apparatus 11 according to Embodiment 1 shown in FIG. 2 in the following point: in Embodiment 1 shown in FIG. 2 , the movable weight 16 is provided such that the movable weight 16 is movable vertically in the linear direction along the guides 25 , whereas in Embodiment 5 shown in FIG. 12 , the movable weight 16 is supported on a predetermined fulcrum 44 , such that the movable weight 16 is vertically swingable about the fulcrum 44 .
- the fulcrum 44 supporting the movable weight 16 as shown in FIG. 12 is provided on the frame 13 a of the turning unit 13 .
- the weight hydraulic cylinder 21 is provided under the movable weight 16 .
- the weight hydraulic cylinder 21 is provided such that the movable weight 16 is vertically swingable about the fulcrum 44 when the cylinder 21 expands and contracts.
- the weight hydraulic cylinder 21 is provided between the lower part of the movable weight 16 and the frame 13 a of the turning unit 13 .
- the proximal end of the cylinder portion 21 a is swingably connected to the frame 13 a of the turning unit 13 via a connection 45 .
- the distal end of the piston rod 21 b is swingably connected to the lower part of the movable weight 16 via the connection 26 .
- the construction machine energy regeneration apparatus 43 according to Embodiment 5 shown in FIG. 12 provides technical advantages as follows. For example, in order to obtain great potential energy of the movable weight 16 , it is necessary to move the movable weight 16 vertically by a great moving distance. For this reason, it is necessary that the stroke of the weight hydraulic cylinder 21 be great. However, considering the structure of the weight hydraulic cylinder 21 , it is desirable that the stroke thereof be relatively small so that stable operation of the weight hydraulic cylinder 21 will be realized, and the hydraulic pressure for raising and lowering of the movable weight 16 can be set to be relatively high.
- the moving distance of the center of gravity of the movable weight 16 in the vertical direction can be made relatively great, and also, the stroke of the weight hydraulic cylinder 21 for vertically swinging the movable weight 16 by a predetermined angle can be set to be relatively small, and in addition, the hydraulic pressure for raising and lowering of the movable weight 16 can be set to be relatively high.
- Embodiment 5 is the same as Embodiment 1 shown in FIG. 2 .
- Common components between Embodiment 1 and Embodiment 5 are denoted by the same reference signs, and the description of such components is omitted.
- Embodiment 6 of the construction machine energy regeneration apparatus according to the present invention is described with reference to FIG. 13 .
- a construction machine energy regeneration apparatus 48 according to Embodiment 6 shown in FIG. 13 is different from the construction machine energy regeneration apparatus 43 according to Embodiment 5 shown in FIG. 12 in the following point: in Embodiment 5 shown in FIG. 12 , one weight hydraulic cylinder 21 is provided between the movable weight 16 and the frame 13 a of the turning unit 13 , whereas in Embodiment 6 shown in FIG.
- one lifting hydraulic cylinder (weight hydraulic cylinder) 21 and one assisting hydraulic cylinder 49 are provided between the movable weight 16 and the frame 13 a of the turning unit 13 .
- the movable weight 16 shown in FIG. 13 is supported on a predetermined fulcrum 44 .
- the movable weight 16 is provided such that the movable weight 16 is vertically swingable about the fulcrum 44 .
- the lifting hydraulic cylinder 21 and the assisting hydraulic cylinder 49 are connected to the movable weight 16 via two connections 26 and 50 , respectively.
- the lifting and assisting hydraulic cylinders 21 and 49 include piston rods 21 b and 49 b, respectively.
- the distal ends of the piston rods 21 b and 49 b are provided with the connections 26 and 50 , respectively.
- the connections 26 and 50 are swingably connected to the movable weight 16 .
- a distance L 2 between the fulcrum 44 and the connection 26 and a distance L 3 between the fulcrum 44 and the connection 50 are set such that the distance L 2 of the lifting hydraulic cylinder 21 is greater than the distance L 3 of the assisting hydraulic cylinder 49 .
- the reference sign G shown in FIG. 13 indicates the position of the center of gravity of the movable weight 16 .
- the power-transmitting hydraulic circuit is configured to guide pressurized oil to the weight hydraulic cylinder 21 to expand the weight hydraulic cylinder 21 at the time of swinging the movable weight 16 upward, and discharge pressurized oil from the assisting hydraulic cylinder 49 to contract the assisting hydraulic cylinder 49 at the time of swinging the movable weight 16 downward.
- the lifting and assisting hydraulic cylinders 21 and 49 include cylinder portions 21 a and 49 a, respectively.
- the proximal ends of the cylinder portions 21 a and 49 a are swingably connected to the frame 13 a of the turning unit 13 via connections 45 and 51 , respectively.
- the pressure of pressurized oil discharged from the assisting cylinder 49 to lower the movable weight 16 can be made higher than the pressure of pressurized oil supplied to the lifting hydraulic cylinder 21 to raise the movable weight 16 . Accordingly, the pressure of the hydraulic fluid for driving the first operating part or the second operating part can be made high, which makes it possible to effectively utilize the potential energy of the movable weight.
- Embodiment 6 is the same as Embodiment 1 shown in FIG. 2 . Therefore, the description of the other features of Embodiment 6 is omitted.
- the present invention is applied to a hydraulic excavator in the above-described embodiments, the present invention is also applicable to other construction machines, for example, a crane.
- hydraulic oil is taken as an example of the hydraulic fluid in the above-described embodiments, a liquid different from hydraulic oil may be used as the hydraulic fluid.
- FIG. 7 , FIG. 8 , FIG. 9 , and FIG. 11 show examples in which the regenerated energy is utilized for driving the arm 19 or the bucket 20 , the regenerated energy can also be utilized for driving the boom 12 , for example.
- the construction machine energy regeneration apparatus and the construction machine including the same make it possible to eliminate the capacitor and the inverter, thereby providing excellent advantages of reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in weight.
- the present invention is suitably applicable to a construction machine energy regeneration apparatus and a construction machine including the same.
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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.
Description
- The present invention relates to a construction machine energy regeneration apparatus included in a construction machine that includes an operating part including a boom, a turning unit, or a running unit driven by a drive unit.
- As one example of a conventional hydraulic excavator, there is a hydraulic excavator that causes an electric motor to regenerate electric power when, for example, reducing the speed of a turning unit, stores the regenerative electric power in a capacitor, uses the regenerative electric power stored in the capacitor to operate the electric motor via a controller and an inverter when turning the turning unit, and assists the rotation of a hydraulic motor with the torque of the electric motor (see
Patent Literature 1, for example). - By thus using the regenerative electric power stored in the capacitor to assist the rotation of the hydraulic motor, the fuel consumption can be reduced.
- PTL 1: Japanese Laid-Open Patent Application Publication No. 2005-290882
- However, the above-described conventional hydraulic excavator needs to include the capacitor and the inverter as equipment for storing the regenerative electric power and utilizing the stored regenerative electric power when turning the turning unit. This causes an increase in cost, a high possibility of the occurrence of a failure, and in addition, size and weight increase. Moreover, the above-described conventional hydraulic excavator goes through multiple steps including: converting mechanical energy of the turning unit into electrical energy; temporarily storing the electrical energy; and then converting the electrical energy into mechanical energy again. Therefore, the overall energy regenerative ratio is not very high, which is another problem. Furthermore, the above-described conventional hydraulic excavator is unable to regenerate potential energy when the hydraulic excavator is in a motion different from turning (i.e., boom lowering, arm crowding, or bucket crowding).
- The present invention has been made to solve the above-described problems. An object of the present invention is to provide a construction machine energy regeneration apparatus and a construction machine including the same, which make it possible to eliminate the capacitor and the inverter, thereby reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in weight.
- A construction machine energy regeneration apparatus according to the present invention is an 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 includes: 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.
- According to the construction machine energy regeneration apparatus of the present invention, the movable weight can be moved (e.g., swung) upward by utilizing energy that is generated when the boom or the like moves in the gravitational direction or energy that is generated when a brake is applied to bring the turning unit or the like to a stop. This makes it possible to store the potential energy of the boom or the like or the kinetic energy of the turning unit or the like as the potential energy of the movable weight.
- Then, the boom, the turning unit, or the like can be driven by utilizing the potential energy of the movable weight.
- Since the potential energy of the boom or the like or the kinetic energy of the turning unit or the like can be stored as the potential energy of the movable weight and utilized as described above, the fuel consumption of the construction machine can be reduced compared to conventional art.
- The construction machine energy regeneration apparatus according to the present invention may include: 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. The switching valve may be configured to shift 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 may be configured to shift 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.
- According to the above power-transmitting hydraulic circuit, the switching valve, which switches the flow direction of the hydraulic fluid in the communication passage, is provided on the communication passage, through which the circuit of the first operating part or the circuit of the second operating part communicates with the circuit of the movable weight. Therefore, potential energy or kinetic energy of the first operating part or the second operating part can be regenerated, and the regenerative energy can be utilized for driving the first operating part or the second operating part.
- The construction machine energy regeneration apparatus according to the present invention may be configured such that the movable weight and a part of the power-transmitting hydraulic circuit have a function as a counter weight of the construction machine, and such that 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.
- By adopting the above configuration, even though the hydraulic excavator includes the energy regeneration apparatus, the total mass of the hydraulic excavator can be made not to exceed the total mass of the hydraulic excavator that does not include the energy regeneration apparatus. This makes it possible to prevent an increase in power for operating the turning unit or the running unit, which is an operating part, as well as an increase in fuel consumption. Consequently, energy can be regenerated and utilized more effectively.
- In the construction machine energy regeneration apparatus according to the present invention, the movable weight may be supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder.
- By adopting the above configuration, the following technical advantages are provided. For example, in order to obtain great potential energy of the movable weight, it is necessary to move the movable weight vertically by a great moving distance. For this reason, it is necessary that the stroke of the hydraulic cylinder be great. However, considering the structure of the hydraulic cylinder, it is desirable that the stroke thereof be relatively small so that stable operation of the hydraulic cylinder will be realized. Accordingly, by providing the movable weight such that the movable weight is vertically swingable about the fulcrum, and setting a distance between the fulcrum and a connection where the hydraulic cylinder is connected to the movable weight to be suitably short, the moving distance of the center of gravity of the movable weight in the vertical direction can be made relatively great, and in addition, the stroke of the hydraulic cylinder for vertically swinging the movable weight by a predetermined angle can be set to be relatively small.
- In the construction machine energy regeneration apparatus according to the present invention, the movable weight may be configured to be movable in a linear direction.
- This makes it possible to provide an inexpensive construction machine energy regeneration apparatus with a simple structure and reduced failures.
- In the construction machine energy regeneration apparatus according to the present invention, the movable weight may be supported on a predetermined fulcrum and vertically swingable about the fulcrum by operation of a hydraulic cylinder. The hydraulic cylinder may include 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 may be 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 may be configured to operate 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 may be configured to operate the assisting cylinder when the movable weight swings downward to drive the first operating part or the second operating part.
- By adopting the above configuration, the following technical advantages are provided. As described above, the distance between the fulcrum and the connection where the lifting cylinder is connected to the movable weight is set to be greater than the distance between the fulcrum and the connection where the assisting cylinder is connected to the movable weight. Accordingly, the pressure discharged from the assisting cylinder to lower the movable weight can be made higher than the pressure supplied to the lifting cylinder to raise the movable weight. Therefore, the pressure of the hydraulic fluid for driving the first operating part or the second operating part can be made high, which makes it possible to widen a pressure range within which the potential energy of the movable weight is utilized.
- The construction machine energy regeneration apparatus according to the present invention may include: 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.
- As described above, based on an operation amount of the remote control valve for operating the boom, the turning unit, or the like and the supply pressure and the discharge pressure of the hydraulic fluid of the boom, the turning unit, or the like, the controller performs control of opening the switching valve via the solenoid pilot valve. This makes it possible to efficiently regenerate the potential energy or kinetic energy of the boom, the turning unit, or the like as the potential energy of the movable weight.
- The construction machine energy regeneration apparatus according to the present invention is configured to regenerate the potential energy of an operating part or kinetic energy based on inertial force, and utilize the regenerative energy for driving an operating part. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art.
- Moreover, the construction machine energy regeneration apparatus according to the present invention makes it possible to eliminate, for example, a capacitor and an inverter for regenerating the potential energy of an operating part or kinetic energy based on inertial force, thereby reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in the weight of the construction machine
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FIG. 1 is a side view showing a hydraulic excavator including a construction machine energy regeneration apparatus according toEmbodiment 1 of the present invention. -
FIG. 2 is a schematic diagram showing, in an exaggerated manner, a movable weight of the construction machine energy regeneration apparatus ofFIG. 1 . -
FIG. 3 shows a hydraulic circuit of the hydraulic excavator ofFIG. 1 . -
FIG. 4 shows a control circuit of a weight switching valve ofFIG. 3 . -
FIG. 5 shows the state of the hydraulic circuit of the hydraulic excavator ofFIG. 3 at the time of boom raising. -
FIG. 6 shows the state of the hydraulic circuit of the hydraulic excavator ofFIG. 3 when energy is regenerated at the time of boom lowering. -
FIG. 7 shows the state of the hydraulic circuit of the hydraulic excavator ofFIG. 3 when regenerative energy is utilized for arm pushing. -
FIG. 8 shows a hydraulic circuit of a hydraulic excavator according to Embodiment 2 in a state where regenerative energy is utilized for bucket pushing. -
FIG. 9 shows a hydraulic circuit of a hydraulic excavator according to Embodiment 3 in a state where regenerative energy is utilized for operating an engine-assisting hydraulic motor and arm pushing. -
FIG. 10 shows a hydraulic circuit of a hydraulic excavator according toEmbodiment 4 in a state where energy is regenerated when a brake is applied to bring a turning unit to a stop. -
FIG. 11 shows the state of the hydraulic circuit of the hydraulic excavator ofFIG. 10 when regenerative energy is utilized for arm pushing. -
FIG. 12 is a schematic diagram showing, in an exaggerated manner, a movable weight of a construction machine energy regeneration apparatus according to Embodiment 5. -
FIG. 13 is a schematic diagram showing, in an exaggerated manner, a movable weight of a construction machine energy regeneration apparatus according to Embodiment 6. - Hereinafter,
Embodiment 1 of a construction machine energy regeneration apparatus according to the present invention is described with reference toFIG. 1 toFIG. 11 . A construction machineenergy regeneration apparatus 11 is included in a construction machine such as ahydraulic excavator 15, whose operating part includes, for example, aboom 12, a turningunit 13, and a runningunit 14 shown inFIG. 1 andFIG. 2 and is driven by a hydraulic fluid discharged from a hydraulic pump 28 (drive unit) shown inFIG. 3 . The construction machineenergy regeneration apparatus 11 includes amovable weight 16 movable vertically and a power-transmittinghydraulic circuit 17A (seeFIG. 3 ). - In the description herein, the
boom 12, the turningunit 13, or the runningunit 14 is referred to as a first operating part, and anarm 19, abucket 20, or an engine-assisting hydraulic motor 52 (seeFIG. 9 ) is referred to as a second operating part. - The power-transmitting
hydraulic circuit 17A shown inFIG. 3 is configured to move themovable weight 16 upward by utilizing, for example, energy that is generated when theboom 12, thearm 19, or thebucket 20 moves in the gravitational direction or energy that is generated when a brake is applied to bring theturning unit 13 or the runningunit 14 to a stop, and utilize the potential energy of themovable weight 16 as energy for driving the first operating part such as theboom 12 or the second operating part such as thearm 19. - In the
hydraulic excavator 15 shown inFIG. 1 , the turningunit 13 is turnably mounted on the runningunit 14 via aturning mechanism 18. Theboom 12 is mounted to the front central part of the turningunit 13, such that theboom 12 is swingable up and down. Thearm 19 is mounted to the distal end of theboom 12, such that thearm 19 is rotatable in a vertical plane. Thebucket 20 is mounted to the distal end of thearm 19, such that thebucket 20 is rotatable in a vertical plane. -
FIG. 2 is a schematic diagram showing, in an exaggerated manner, themovable weight 16, which is provided at the rear of the turningunit 13 of thehydraulic excavator 15. Themovable weight 16 has a function of storing the gravitational force of theboom 12 or the like as potential energy, and has a function as a counter weight of thehydraulic excavator 15. - Specifically, the
movable weight 16 and a part of the power-transmittinghydraulic circuit 17A have a function as a counter weight of thehydraulic excavator 15, and the total mass of themovable weight 16 and the part of the power-transmittinghydraulic circuit 17A is set to be substantially equal to the mass of a counter weight required by thehydraulic excavator 15. - The shape and the material of the
movable weight 16 shown inFIG. 2 are equivalent to those of a conventional counter weight. Themovable weight 16 is provided at the rear of the turningunit 13, and is positioned at the opposite side to theboom 12 with respect to theturning mechanism 18. Themovable weight 16 is provided such that themovable weight 16 is movable vertically in a linear direction along guides 25. A weighthydraulic cylinder 21 is provided under themovable weight 16. - The weight
hydraulic cylinder 21 supports themovable weight 16 such that themovable weight 16 is movable vertically in the linear direction. The weighthydraulic cylinder 21 is provided between the lower part of themovable weight 16 and aframe 13 a of the turningunit 13. The weighthydraulic cylinder 21 includes: acylinder portion 21 a whose proximal end is fixed to theframe 13 a of the turningunit 13; and apiston rod 21 b whose distal end is swingably connected to the lower part of themovable weight 16 via aconnection 26. -
FIG. 3 shows ahydraulic circuit 27 including the power-transmittinghydraulic circuit 17A of thehydraulic excavator 15. Thehydraulic circuit 27 includes communication passages 22 (22 a, 22 b, and 22 c) and aweight switching valve 24. It should be noted that, inFIG. 3 , circuits other than those of theboom 12 and thearm 19 are omitted. - The
communication passages 22 are passages through which the circuits of the first operating part and the second operating part, including boom communication passages 53 (53 a and 53 b) and arm communication passages 54 (54 a and 54 b), communicate with movable weight communication passages 55 (55 a and 55 b). - The
weight switching valve 24 is connected to thecommunication passages 22, and serves to switch the flow direction of the hydraulic fluid in thecommunication passages 22. - The
weight switching valve 24 shifts to a first position (II) when theboom 12, thearm 19, or thebucket 20 moves in the gravitational direction or when a brake is applied to bring theturning unit 13 or the runningunit 14 to a stop, such that the hydraulic fluid flows through thecommunication passages 22 and theweight switching valve 24, and thereby themovable weight 16 can be moved upward. - The
weight switching valve 24 shifts to a second position (III) when themovable weight 16 moves in the gravitational direction, such that the hydraulic fluid flows through thecommunication passages 22 and theweight switching valve 24, and thereby the first operating part including theboom 12 or the second operating part including thearm 19 can be driven. - Specifically, for example, ports A and B of the
weight switching valve 24 shown inFIG. 3 are connected to a head-side port of the weighthydraulic cylinder 21 and a rod-side port of the weighthydraulic cylinder 21 via the movableweight communication passages weight switching valve 24 are connected to each other. A port T of theweight switching valve 24 is connected to atank 32, and a port P of theweight switching valve 24 is connected to a discharge port of thehydraulic pump 28 via thecommunication passage 22. A port D of theweight switching valve 24 is connected to thearm communication passage 54 a via thecommunication passage 22 a. Thecommunication passage 22 a is provided with a check valve. - The
hydraulic circuit 27 shown inFIG. 3 includes control valves for the first operating part including theboom 12 and control valves for the second operating part including thearm 19. Each of these control valves serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to the first operating part or the second operating part. -
FIG. 3 shows anarm control valve 56 and aboom control valve 57. - The
arm control valve 56 serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to an armhydraulic cylinder 37. Ports A and B of thearm control valve 56 are connected to two ports (rod-side and head-side ports) of the armhydraulic cylinder 37 via thearm communication passages arm control valve 56 is connected to thetank 32 via atank communication passage 60, and a port P of thearm control valve 56 is connected to the discharge port of thehydraulic pump 28 via apump communication passage 61. - The
boom control valve 57 serves to control the pressure and the flow rate of the hydraulic fluid that is supplied to a boomhydraulic cylinder 39. Ports A and B of theboom control valve 57 are connected to two ports (rod-side and head-side ports) of the boomhydraulic cylinder 39 via theboom communication passages boom control valve 57 is connected to thetank 32 via atank communication passage 62, and a port P of theboom control valve 57 is connected to the discharge port of thehydraulic pump 28 via apump communication passage 63. -
FIG. 3 shows remote control valves, each of which serves to supply a pilot pressure liquid to pilot ports of a corresponding one of the above control valves. -
FIG. 3 shows an armremote control valve 64 and a boomremote control valve 65. - The arm
remote control valve 64 is operated by an operator and serves to supply the pilot pressure liquid to pilot ports X and Y of thearm control valve 56 throughcommunication passages - The boom
remote control valve 65 is operated by the operator and serves to supply the pilot pressure liquid to pilot ports X and Y of theboom control valve 57 throughcommunication passage - First to tenth pressure sensors PS1 to PS10 serve to: measure a supply pressure and a discharge pressure of the hydraulic fluid of the first operating part or the second operating part; measure output pressures of the remote control valves; and generate pressure signals as electrical signals.
FIG. 3 shows first to sixth pressure sensors PS1 to PS6. - The first and second pressure sensors PS1 and PS2 serve to measure output pressures of the boom
remote control valve 65, which occur in thecommunication passages - The third and fourth pressure sensors PS3 and PS4 serve to measure output pressures of the arm
remote control valve 64, which occur in thecommunication passages - The fifth and sixth pressure sensors PS5 and PS6 serve to measure output pressures that occur in the
boom communication passages hydraulic cylinder 39, and generate pressure signals as electrical signals. - The
hydraulic circuit 27 shown inFIG. 3 further includes acontrol circuit 70 shown inFIG. 4 . Thecontrol circuit 70 shown inFIG. 4 includes first and secondsolenoid pilot valves 71 and 72 and acontroller 73. - The first
solenoid pilot valve 71 shown inFIG. 4 serves to supply a pilot pressure liquid to a pilot port Pia of theweight switching valve 24 shown inFIG. 3 in accordance with a current flowing through afirst signal line 71 a. The pressure source of the pilot pressure liquid is a hydraulic pressure discharged from a controlhydraulic pump 74. - The second solenoid pilot valve 72 serves to supply a pilot pressure liquid to a pilot port Pib of the
weight switching valve 24 shown inFIG. 3 in accordance with a current flowing through asecond signal line 72 a. The pressure source of the pilot pressure liquid is a hydraulic pressure discharged from the controlhydraulic pump 74. - The
controller 73 serves to electrically receive electrical pressure signals outputted from the first to tenth pressure sensors PS1 to PS10, and transmit electrical command signals to the first and secondsolenoid pilot valves 71 and 72 based on the electrical pressure signals. - Next, functions of the construction machine
energy regeneration apparatus 11 are described with reference toFIG. 5 toFIG. 11 .FIG. 5 shows the state of thehydraulic circuit 27 and thecontrol circuit 70 ofFIG. 3 andFIG. 4 of thehydraulic excavator 15 at the time of raising of theboom 12. When the operator operates the boomremote control valve 65 for raising of theboom 12, the spool of theboom control valve 57 shifts to the position (III), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the boomhydraulic cylinder 39 as indicated by a bold solid line, and thereby theboom 12 can be raised to a desired height. - At the time, the pressurized oil discharged from the
hydraulic pump 28 is supplied also to theweight switching valve 24. However, since the port P is closed at the time, the pressurized oil is not supplied to the weighthydraulic cylinder 21. Accordingly, themovable weight 16 remains stopped without being raised or lowered. -
FIG. 6 shows the state of thehydraulic circuit 27 and thecontrol circuit 70 ofFIG. 3 andFIG. 4 when energy is regenerated at the time of lowering of theboom 12. When the operator operates the boomremote control valve 65 for lowering of theboom 12, the spool of theboom control valve 57 shifts to the position (II), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the boomhydraulic cylinder 39 as indicated by a bold solid line, and thereby theboom 12 can be lowered to a desired height. At the time, pressurized oil discharged from the boomhydraulic cylinder 39 is supplied to theweight switching valve 24. - Then, the
controller 73 electrically receives electrical pressure signals outputted from the fifth and sixth pressure sensors PS5 and PS6, and transmits an electrical command signal to the second solenoid pilot valve 72 based on the electrical pressure signals. In response, the spool of theweight switching valve 24 shifts to the position (II), such that pressurized oil discharged from the boomhydraulic cylinder 39 is, as indicated by a bold one-dot chain line, supplied to the weighthydraulic cylinder 21 through theweight switching valve 24, and thereby themovable weight 16 can be raised. - At the time, based on an operation amount of the boom
remote control valve 65 for operating theboom 12, and the supply pressure and the discharge pressure of the hydraulic fluid of the boom 12 (i.e., electrical pressure signals from the fifth and sixth pressure sensors PS5 and PS6), thecontroller 73 performs control of opening theweight switching valve 24 via the second solenoid pilot valve 72. This makes it possible to efficiently regenerate the potential energy of theboom 12 as the potential energy of themovable weight 16. -
FIG. 6 illustrates an example in which the potential energy of theboom 12 is regenerated as the potential energy of themovable weight 16. However, alternatively, the potential energy of thearm 19, thebucket 20, or the like can be regenerated as the potential energy of themovable weight 16 although it is not shown in the drawings. -
FIG. 7 shows the state of thehydraulic circuit 27 and thecontrol circuit 70 ofFIG. 3 andFIG. 4 when regenerative energy is utilized for pushing of thearm 19. When the operator operates the armremote control valve 64 for pushing of thearm 19, the spool of thearm control valve 56 shifts to the position (II), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the armhydraulic cylinder 37 as indicated by a bold solid line and a bold one-dot chain line, and thereby thearm 19 can be swung in the pushing direction. - At the time, the
controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the armhydraulic cylinder 37, and transmits an electrical command signal to the firstsolenoid pilot valve 71 based on the electrical pressure signals. In response, the spool of theweight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weighthydraulic cylinder 21 is supplied to the armhydraulic cylinder 37 through theweight switching valve 24 as indicated by a bold one-dot chain line, and thereby thearm 19 can be swung in the pushing direction. In this manner, regenerative energy can be utilized for pushing of thearm 19. - That is, as shown in
FIG. 6 , themovable weight 16 can be moved upward by utilizing energy that is generated when theboom 12 moves in the gravitational direction (i.e., when theboom 12 is lowered). In this manner, the potential energy of theboom 12 can be stored as the potential energy of themovable weight 16. - Then, as shown in
FIG. 7 , the potential energy of themovable weight 16 can be utilized to drive thearm 19 in the pushing direction. - Thus, the potential energy of the
boom 12 can be stored as the potential energy of themovable weight 16 and utilized as described above. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art. - Further, as shown in
FIG. 2 , themovable weight 16 has a function as a counter weight of such a construction machine as thehydraulic excavator 15. The total mass of themovable weight 16 and a part of the power-transmittinghydraulic circuit 17A (17B and 17C inEmbodiments 3 and 4 described below) is set to be substantially equal to the mass of a counter weight required by the construction machine. - Accordingly, even though the
hydraulic excavator 15 includes theenergy regeneration apparatus 11, the total mass of thehydraulic excavator 15 can be made not to exceed the total mass of thehydraulic excavator 15 that does not include theenergy regeneration apparatus 11. This makes it possible to prevent an increase in power for operating the turningunit 13 or the runningunit 14, which is an operating part, as well as an increase in fuel consumption. Consequently, energy can be regenerated and utilized more effectively. - Further, as shown in
FIG. 2 , themovable weight 16 is provided such that themovable weight 16 is movable in a linear direction. This makes it possible to provide an inexpensive construction machineenergy regeneration apparatus 11 with a simple structure and reduced failures. -
FIG. 8 shows a hydraulic circuit of Embodiment 2 of the present invention in a state where regenerative energy is utilized for driving thebucket 20. - A
bucket control valve 58 serves to control the pressure and the flow rate of a hydraulic fluid supplied to a buckethydraulic cylinder 38. Similar to the above-described configuration, thebucket control valve 58 is connected to the buckethydraulic cylinder 38, thetank 32, and thehydraulic pump 28. - A bucket
remote control valve 66 is connected to pilot ports X and Y of thebucket control valve 58 via communication passages 66 b and 66 a. - The seventh and eighth pressure sensors PS7 and PS8 shown in
FIG. 8 serve to measure output pressures of the bucketremote control valve 66, which occur in the communication passages 66 a and 66 b, and generate pressure signals as electrical signals. -
FIG. 8 shows the state of thehydraulic circuit 27 and thecontrol circuit 70 ofFIG. 3 andFIG. 4 when regenerative energy is utilized for pushing of thebucket 20. The state shown inFIG. 8 is different from the state shown inFIG. 7 in the following point: in the state shown inFIG. 7 , regenerative energy is utilized for pushing of thearm 19, whereas in the state shown inFIG. 8 , regenerative energy is utilized for pushing of thebucket 20. - Referring to
FIG. 8 , when the operator operates the bucketremote control valve 66 for pushing of thebucket 20, the spool of thebucket control valve 58 shifts to the position (II), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the buckethydraulic cylinder 38 as indicated by a bold solid line and a bold one-dot chain line, and thereby thebucket 20 can be swung in the pushing direction. - At the time, the
controller 73 operates in the same manner as in the case shown inFIG. 7 , such that pressurized oil discharged from the weighthydraulic cylinder 21 is supplied to the buckethydraulic cylinder 38 through theweight switching valve 24 as indicated by a bold one-dot chain line, and thereby thebucket 20 can be swung in the pushing direction. - In this manner, regenerative energy (i.e., potential energy of the movable weight 16) can be utilized for pushing of the
bucket 20. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art. -
FIG. 9 shows ahydraulic circuit 75 of Embodiment 3. In Embodiment 3, thehydraulic circuit 75 includes the power-transmittinghydraulic circuit 17B of thehydraulic excavator 15, and is configured such that thecommunication passage 22 a for the engine-assistinghydraulic motor 52 is added to thehydraulic circuit 27 shown inFIG. 3 .FIG. 9 shows a state where the engine-assistinghydraulic motor 52 is driven by regenerative energy, and regenerative energy is utilized for pushing of thearm 19. - When the operator operates the arm
remote control valve 64 for pushing of thearm 19, the spool of thearm control valve 56 shifts to the position (II), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the armhydraulic cylinder 37 as indicated by a bold solid line, and thereby thearm 19 can be swung in the pushing direction. - At the time, the
controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the armhydraulic cylinder 37, and transmits an electrical command signal to the firstsolenoid pilot valve 71 based on the electrical pressure signals. In response, the spool of theweight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weighthydraulic cylinder 21 is supplied to the engine-assistinghydraulic motor 52 through theweight switching valve 24 and thecommunication passage 22 a as indicated by a bold one-dot chain line. As a result, the engine-assistinghydraulic motor 52 rotates, and thereby driving of thehydraulic pump 28, which is connected to the rotary shaft of the engine-assistinghydraulic motor 52, can be assisted. - In this manner, regenerative energy (potential energy of the movable weight 16) can be utilized for pushing of the
arm 19. This makes it possible to reduce the fuel consumption of the construction machine compared to conventional art. - It should be noted that, as shown in
FIG. 9 , the port D of theweight switching valve 24 is connected to the oil inlet of the engine-assistinghydraulic motor 52 via thecommunication passage 22 a. -
FIG. 10 shows ahydraulic circuit 76 ofEmbodiment 4. InEmbodiment 4, thehydraulic circuit 76 includes the power-transmitting hydraulic circuit 17C of thehydraulic excavator 15, and is configured such that turningunit communication passages hydraulic circuit 27 shown inFIG. 3 instead of theboom communication passages check valves unit communication passages FIG. 10 shows a turningunit control valve 59. - The turning
unit control valve 59 serves to control the pressure and the flow rate of a hydraulic fluid supplied to a turning unithydraulic motor 36. Similar to the configuration previously described, the turningunit control valve 59 is connected to the turning unithydraulic motor 36, thetank 32, and thehydraulic pump 28. - A turning unit
remote control valve 67 is connected to pilot ports X and Y of the turningunit control valve 59 viacommunication passages - The ninth and tenth pressure sensors PS9 and PS10 shown in
FIG. 10 serve to measure output pressures of the turning unitremote control valve 67, which occur in thecommunication passages FIG. 10 shows a state where energy is regenerated when a brake is applied to bring theturning unit 13 to a stop. - For example, the operator operates the turning unit
remote control valve 67 in order to apply a brake to bring theturning unit 13 to a stop while the turningunit 13 is turning in a reverse direction. In response, the spool of the turningunit control valve 59 shifts from the position (II) to position (I), such that the outlet side of the turning unithydraulic motor 36 is blocked by the turningunit control valve 59. - In parallel with the above operation, the
controller 73 electrically receives electrical pressure signals outputted from the ninth and tenth pressure sensors PS9 and PS10, and transmits an electrical command signal to the second solenoid pilot valve 72 based on the electrical pressure signals. In response, the spool of theweight switching valve 24 shifts to the position II, such that pressurized oil discharged from the turning unithydraulic motor 36 is supplied to the weighthydraulic cylinder 21 through theweight switching valve 24 as indicated by a bold one-dot chain line, and thereby themovable weight 16 can be raised. It should be noted that, at the time, the turning unithydraulic motor 36 sucks the pressurized oil from thetank 32. - In this manner, energy generated at the time of applying a brake to bring the
turning unit 13 to a stop can be stored as the potential energy of themovable weight 16. - Then, at the time, based on the operation amount of the turning unit
remote control valve 67 for operating the turningunit 13, and the supply pressure and the discharge pressure of the hydraulic fluid of the turning unit 13 (i.e., signals from the ninth and tenth pressure sensors PS9 and PS10), thecontroller 73 performs control of opening theweight switching valve 24 via the second solenoid pilot valve 72. This makes it possible to efficiently regenerate the kinetic energy of the turningunit 13 as the potential energy of themovable weight 16. -
FIG. 10 illustrates an example in which the kinetic energy of the turningunit 13 is regenerated as the potential energy of themovable weight 16. However, alternatively, the kinetic energy of the runningunit 14 can be regenerated as the potential energy of themovable weight 16 although it is not shown in the drawings. - It should be noted that, as shown in
FIG. 10 , the port P of theweight switching valve 24 is connected to the oil inlet port and the oil outlet port of the turning unithydraulic motor 36 via acommunication passage 36 a. Thereference sign 77 inFIG. 10 indicates relief valves for controlling the discharge pressure of thehydraulic pump 28. -
FIG. 11 shows the state of thehydraulic circuit 76 of thehydraulic excavator 15 ofFIG. 10 when regenerative energy is utilized for pushing of thearm 19. - When the operator operates the arm
remote control valve 64 for pushing of thearm 19, the spool of thearm control valve 56 shifts to the position (II), such that pressurized oil discharged from thehydraulic pump 28 is supplied to the armhydraulic cylinder 37 as indicated by a bold solid line and a bold one-dot chain line, and thereby thearm 19 can be swung in the pushing direction. - At the time, the
controller 73 electrically receives electrical pressure signals outputted from pressure sensors (not shown) connected to the armhydraulic cylinder 37, and transmits an electrical command signal to the firstsolenoid pilot valve 71 based on the electrical pressure signals. In response, the spool of theweight switching valve 24 shifts to the position (III), such that pressurized oil discharged from the weighthydraulic cylinder 21 is supplied to the armhydraulic cylinder 37 through theweight switching valve 24 and thecommunication passages arm 19 can be swung in the pushing direction. In this manner, the driving of thehydraulic pump 28 can be assisted. - As described above, regenerative energy (potential energy of the movable weight 16) can be utilized for pushing of the
arm 19. - That is, as shown in
FIG. 10 , by utilizing the kinetic energy that is generated when a brake is applied to bring theturning unit 13 to a stop, themovable weight 16 can be moved upward. In this manner, the kinetic energy of the turningunit 13 can be stored as the potential energy of themovable weight 16. - Then, the
arm 19 can be driven by utilizing the potential energy of themovable weight 16. - Thus, the kinetic energy of the turning
unit 13 can be stored as the potential energy of themovable weight 16 and utilized as described above. This makes it possible to reduce the fuel consumption of a construction machine compared to conventional art. - Next, Embodiment 5 of the construction machine energy regeneration apparatus according to the present invention is described with reference to
FIG. 12 . A construction machineenergy regeneration apparatus 43 according to Embodiment 2 shown inFIG. 12 is different from the construction machineenergy regeneration apparatus 11 according toEmbodiment 1 shown inFIG. 2 in the following point: inEmbodiment 1 shown inFIG. 2 , themovable weight 16 is provided such that themovable weight 16 is movable vertically in the linear direction along theguides 25, whereas in Embodiment 5 shown inFIG. 12 , themovable weight 16 is supported on apredetermined fulcrum 44, such that themovable weight 16 is vertically swingable about thefulcrum 44. - The fulcrum 44 supporting the
movable weight 16 as shown inFIG. 12 is provided on theframe 13 a of the turningunit 13. The weighthydraulic cylinder 21 is provided under themovable weight 16. - The weight
hydraulic cylinder 21 is provided such that themovable weight 16 is vertically swingable about the fulcrum 44 when thecylinder 21 expands and contracts. - The weight
hydraulic cylinder 21 is provided between the lower part of themovable weight 16 and theframe 13 a of the turningunit 13. The proximal end of thecylinder portion 21 a is swingably connected to theframe 13 a of the turningunit 13 via aconnection 45. The distal end of thepiston rod 21 b is swingably connected to the lower part of themovable weight 16 via theconnection 26. - The construction machine
energy regeneration apparatus 43 according to Embodiment 5 shown inFIG. 12 provides technical advantages as follows. For example, in order to obtain great potential energy of themovable weight 16, it is necessary to move themovable weight 16 vertically by a great moving distance. For this reason, it is necessary that the stroke of the weighthydraulic cylinder 21 be great. However, considering the structure of the weighthydraulic cylinder 21, it is desirable that the stroke thereof be relatively small so that stable operation of the weighthydraulic cylinder 21 will be realized, and the hydraulic pressure for raising and lowering of themovable weight 16 can be set to be relatively high. - Accordingly, by providing the
movable weight 16 such that themovable weight 16 is vertically swingable about thefulcrum 44, and setting a distance L1 between the fulcrum 44 and theconnection 26 where the weighthydraulic cylinder 21 is connected to themovable weight 16 to be suitably short, the moving distance of the center of gravity of themovable weight 16 in the vertical direction can be made relatively great, and also, the stroke of the weighthydraulic cylinder 21 for vertically swinging themovable weight 16 by a predetermined angle can be set to be relatively small, and in addition, the hydraulic pressure for raising and lowering of themovable weight 16 can be set to be relatively high. - Other than the above-described features, Embodiment 5 is the same as
Embodiment 1 shown inFIG. 2 . Common components betweenEmbodiment 1 and Embodiment 5 are denoted by the same reference signs, and the description of such components is omitted. - Next, Embodiment 6 of the construction machine energy regeneration apparatus according to the present invention is described with reference to
FIG. 13 . A construction machineenergy regeneration apparatus 48 according to Embodiment 6 shown inFIG. 13 is different from the construction machineenergy regeneration apparatus 43 according to Embodiment 5 shown inFIG. 12 in the following point: in Embodiment 5 shown inFIG. 12 , one weighthydraulic cylinder 21 is provided between themovable weight 16 and theframe 13 a of the turningunit 13, whereas in Embodiment 6 shown inFIG. 13 , for example, one lifting hydraulic cylinder (weight hydraulic cylinder) 21 and one assisting hydraulic cylinder 49, i.e., a total of two cylinders, are provided between themovable weight 16 and theframe 13 a of the turningunit 13. - Similar to Embodiment 5 shown in
FIG. 12 , themovable weight 16 shown inFIG. 13 is supported on apredetermined fulcrum 44. Themovable weight 16 is provided such that themovable weight 16 is vertically swingable about thefulcrum 44. The liftinghydraulic cylinder 21 and the assisting hydraulic cylinder 49 are connected to themovable weight 16 via twoconnections - The lifting and assisting
hydraulic cylinders 21 and 49 includepiston rods piston rods connections connections movable weight 16. A distance L2 between the fulcrum 44 and theconnection 26 and a distance L3 between the fulcrum 44 and theconnection 50 are set such that the distance L2 of the liftinghydraulic cylinder 21 is greater than the distance L3 of the assisting hydraulic cylinder 49. It should be noted that the reference sign G shown inFIG. 13 indicates the position of the center of gravity of themovable weight 16. - Although not shown in the drawings, the power-transmitting hydraulic circuit is configured to guide pressurized oil to the weight
hydraulic cylinder 21 to expand the weighthydraulic cylinder 21 at the time of swinging themovable weight 16 upward, and discharge pressurized oil from the assisting hydraulic cylinder 49 to contract the assisting hydraulic cylinder 49 at the time of swinging themovable weight 16 downward. - The lifting and assisting
hydraulic cylinders 21 and 49 includecylinder portions 21 a and 49 a, respectively. The proximal ends of thecylinder portions 21 a and 49 a are swingably connected to theframe 13 a of the turningunit 13 viaconnections - As described above, by setting the distance L2 between the fulcrum 44 and the
connection 26 of the liftinghydraulic cylinder 21 connected to themovable weight 16 and the distance L3 between the fulcrum 44 and theconnection 50 of the assisting hydraulic cylinder 49 connected to themovable weight 16, such that the distance L2 of the weighthydraulic cylinder 21 is greater than the distance L3 of the assisting hydraulic cylinder 49, the pressure of pressurized oil discharged from the assisting cylinder 49 to lower themovable weight 16 can be made higher than the pressure of pressurized oil supplied to the liftinghydraulic cylinder 21 to raise themovable weight 16. Accordingly, the pressure of the hydraulic fluid for driving the first operating part or the second operating part can be made high, which makes it possible to effectively utilize the potential energy of the movable weight. - Other than the above-described features, Embodiment 6 is the same as
Embodiment 1 shown inFIG. 2 . Therefore, the description of the other features of Embodiment 6 is omitted. - Although the present invention is applied to a hydraulic excavator in the above-described embodiments, the present invention is also applicable to other construction machines, for example, a crane.
- Although hydraulic oil is taken as an example of the hydraulic fluid in the above-described embodiments, a liquid different from hydraulic oil may be used as the hydraulic fluid.
- Although
FIG. 7 ,FIG. 8 ,FIG. 9 , andFIG. 11 show examples in which the regenerated energy is utilized for driving thearm 19 or thebucket 20, the regenerated energy can also be utilized for driving theboom 12, for example. - As described above, the construction machine energy regeneration apparatus and the construction machine including the same, according to the present invention, make it possible to eliminate the capacitor and the inverter, thereby providing excellent advantages of reducing the cost to be inexpensive, reducing failures, and reducing the size to suppress an increase in weight. Thus, the present invention is suitably applicable to a construction machine energy regeneration apparatus and a construction machine including the same.
- 11 construction machine energy regeneration apparatus
- 12 boom
- 13 turning unit
- 13 a frame
- 14 running unit
- 15 hydraulic excavator (construction machine)
- 16 movable weight
- 17A, 17B, 17C power-transmitting hydraulic circuit
- 18 turning mechanism
- 19 arm
- 20 bucket
- 21 weight hydraulic cylinder (lifting hydraulic cylinder)
- 21 a cylinder portion
- 21 b piston portion
- 22, 22 a, 22 b, 22 c communication passage
- 24 weight switching valve
- 25 guide
- 26 connection
- 27 hydraulic circuit
- 28 hydraulic pump
- 32 tank
- 36 turning unit hydraulic motor
- 36 a communication passage
- 37 arm hydraulic cylinder
- 38 bucket hydraulic cylinder
- 39 boom hydraulic cylinder
- 43 construction machine energy regeneration apparatus
- 44 fulcrum
- 45 connection
- 48 construction machine energy regeneration apparatus
- 49 assisting hydraulic cylinder
- 49 a cylinder portion
- 49 b piston portion
- 50, 51 connection
- 52 engine-assisting hydraulic motor
- 53, 53 a, 53 b boom communication passage
- 54, 54 a, 54 b arm communication passage
- 55, 55 a, 55 b movable weight communication passage
- 56 arm control valve
- 57 boom control valve
- 58 bucket control valve
- 59 turning unit control valve
- 60, 62 tank communication passage
- 61, 63 pump communication passage
- 64 arm remote control valve
- 64 a, 64 b, 65 a, 65 b, 66 a, 66 b, 67 a, 67 b communication passage
- 65 boom remote control valve
- 66 bucket remote control valve
- 67 turning unit remote control valve
- 68 a, 68 b bucket communication passage
- 69 a, 69 b turning unit communication passage
- 70 control circuit
- 71 first solenoid pilot valve
- 71 a first signal line
- 72 second solenoid pilot valve
- 72 a second signal line
- 73 controller
- 74 control hydraulic pump
- 75, 76 hydraulic circuit
- 77 relief valve
- 78 a, 78 b check valve
Claims (7)
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.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2013-162303 | 2013-08-05 | ||
JP2013162303 | 2013-08-05 | ||
PCT/JP2014/004063 WO2015019594A1 (en) | 2013-08-05 | 2014-08-04 | Energy regeneration device for construction machine |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160122980A1 true US20160122980A1 (en) | 2016-05-05 |
Family
ID=52460950
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US14/895,081 Abandoned US20160122980A1 (en) | 2013-08-05 | 2014-08-04 | Construction machine energy regeneration apparatus |
Country Status (5)
Country | Link |
---|---|
US (1) | US20160122980A1 (en) |
JP (1) | JP6285935B2 (en) |
CN (1) | CN105164347B (en) |
GB (1) | GB2531946A (en) |
WO (1) | WO2015019594A1 (en) |
Cited By (5)
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US20170350094A1 (en) * | 2015-01-06 | 2017-12-07 | Kawasaki Jukogyo Kabushiki Kaisha | Drive control system of operating machine, operating machine including drive control system, and drive control method of operating machine |
CN108180189A (en) * | 2018-02-26 | 2018-06-19 | 太原科技大学 | Storage dirt bucket lifting device and method of a kind of electric cleaning car with energy regenerating |
US20180171652A1 (en) * | 2016-12-16 | 2018-06-21 | International Chimney Corporation | Liner removal apparatus |
CN110616758A (en) * | 2019-10-25 | 2019-12-27 | 董志强 | Energy-saving control system of excavator |
DE102020113815A1 (en) | 2020-05-22 | 2021-11-25 | Marcel Hett | Hydraulic mobile excavator |
Families Citing this family (4)
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JP6816444B2 (en) * | 2016-10-20 | 2021-01-20 | コベルコ建機株式会社 | Vibration damping device for construction machinery |
KR102177815B1 (en) * | 2017-12-14 | 2020-11-11 | 한국오텍 주식회사 | Apparatus for compensating the weight of heavy machinery boom |
CN110409527A (en) * | 2019-06-28 | 2019-11-05 | 三一重机有限公司 | A kind of movable arm potential energy recycling system and excavator |
CN112555207A (en) * | 2020-12-01 | 2021-03-26 | 上海华兴数字科技有限公司 | Hydraulic control system and mechanical equipment |
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US20130133966A1 (en) * | 2010-05-13 | 2013-05-30 | Jinan Jenhang Energy-Saving Technology Co., Ltd. | Traveling hydraulic handling machine of energy-saving type |
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CN100392257C (en) * | 2003-01-14 | 2008-06-04 | 日立建机株式会社 | Hydraulic working machine |
JP2006336844A (en) * | 2005-06-06 | 2006-12-14 | Shin Caterpillar Mitsubishi Ltd | Working machine |
SE531309C2 (en) * | 2006-01-16 | 2009-02-17 | Volvo Constr Equip Ab | Control system for a working machine and method for controlling a hydraulic cylinder of a working machine |
JP2012026245A (en) * | 2010-07-28 | 2012-02-09 | Hitachi Constr Mach Co Ltd | Construction machinery |
JP5604324B2 (en) * | 2011-02-02 | 2014-10-08 | 日立建機株式会社 | Hydraulic drive device for work machine |
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2014
- 2014-08-04 GB GB1519561.3A patent/GB2531946A/en not_active Withdrawn
- 2014-08-04 US US14/895,081 patent/US20160122980A1/en not_active Abandoned
- 2014-08-04 CN CN201480026051.XA patent/CN105164347B/en active Active
- 2014-08-04 WO PCT/JP2014/004063 patent/WO2015019594A1/en active Application Filing
- 2014-08-04 JP JP2015530698A patent/JP6285935B2/en active Active
Patent Citations (1)
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US20130133966A1 (en) * | 2010-05-13 | 2013-05-30 | Jinan Jenhang Energy-Saving Technology Co., Ltd. | Traveling hydraulic handling machine of energy-saving type |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170350094A1 (en) * | 2015-01-06 | 2017-12-07 | Kawasaki Jukogyo Kabushiki Kaisha | Drive control system of operating machine, operating machine including drive control system, and drive control method of operating machine |
US10435866B2 (en) * | 2015-01-06 | 2019-10-08 | Kawasaki Jukogyo Kabushiki Kaisha | Drive control system of operating machine, operating machine including drive control system, and drive control method of operating machine |
US20180171652A1 (en) * | 2016-12-16 | 2018-06-21 | International Chimney Corporation | Liner removal apparatus |
US10890003B2 (en) * | 2016-12-16 | 2021-01-12 | International Chimney Corporation | Liner removal apparatus |
CN108180189A (en) * | 2018-02-26 | 2018-06-19 | 太原科技大学 | Storage dirt bucket lifting device and method of a kind of electric cleaning car with energy regenerating |
CN110616758A (en) * | 2019-10-25 | 2019-12-27 | 董志强 | Energy-saving control system of excavator |
DE102020113815A1 (en) | 2020-05-22 | 2021-11-25 | Marcel Hett | Hydraulic mobile excavator |
Also Published As
Publication number | Publication date |
---|---|
JPWO2015019594A1 (en) | 2017-03-02 |
WO2015019594A1 (en) | 2015-02-12 |
GB2531946A (en) | 2016-05-04 |
CN105164347B (en) | 2017-11-03 |
CN105164347A (en) | 2015-12-16 |
GB201519561D0 (en) | 2015-12-23 |
JP6285935B2 (en) | 2018-02-28 |
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