KR101121705B1 - Apparatus And Method For Recovering Potential Energy Of Boom In A Construction Machinery - Google Patents

Abstract

The present invention relates to a boom potential energy regeneration device and method of construction machinery. According to one aspect of the invention, the electric motor driven in the forward, reverse direction in accordance with the control signal input; A bidirectional hydraulic pump driven in both directions by an electric motor; A large chamber line formed between the two-way hydraulic pump and the large chamber of the boom hydraulic cylinder and through which hydraulic fluid flows; A small chamber line formed between the two-way hydraulic pump and the small chamber of the boom hydraulic cylinder and through which hydraulic fluid flows; A boom hydraulic cylinder including a large chamber and a small chamber and being telescopically driven by hydraulic oil in the large chamber and the small chamber; Forming flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively, and forming a return line and an outlet port connected to the tank, block the return line to the tank when the boom is raised, and the small chamber line and the return when the boom is lowered. A direction control valve unit forming a flow path between lines; A return line through which hydraulic oil is returned to the tank from the outlet port of the directional control valve; A generator that is generated by driving a hydraulic pump reversely driven by hydraulic oil flowing from the high pressure large chamber line to the low pressure small chamber line when the boom is lowered; A battery storing electrical energy generated by a generator; And a main controller for outputting a control signal to drive the electric motor, the generator, and the direction control valve unit according to a user's operation signal. It is made, including, here it proposes a boom potential energy regeneration device for a construction machine, characterized in that to use the electrical energy stored in the battery when the boom rises.

Construction machinery, boom, potential energy, regeneration, two-way hydraulic pump, electric motor, directional control valve, excavation

Description

Apparatus And Method For Recovering Potential Energy Of Boom In A Construction Machinery}

The present invention relates to a boom potential energy regeneration device and method of construction machinery. Specifically, the hydraulic cylinder of the boom is raised and lowered by controlling the forward and reverse rotation direction and speed of the electric motor in place of the direction change valve of the existing hydraulic system, and the electric pressure is applied by the hydraulic pressure according to the position energy during the lowering operation of the boom cylinder. The present invention relates to a boom potential energy regeneration device and method for construction machinery capable of generating energy and charging energy.

In general, the hydraulic system has a high output per unit area and simple and accurate overload protection. In addition, the force adjustment is easy, accurate, low vibration, smooth operation, etc. are used in a field that requires a large force, for example, heavy construction equipment such as excavators, cranes. On the other hand, in the heavy construction equipment, the hydraulic system is driven even when not operated by a driving device (engine, motor, etc.) that drives a hydraulic pump that supplies hydraulic oil to an actuator such as a hydraulic cylinder. have. In the case of excavators, especially, even when the engine power is maximized, only about 20% is effectively used, which requires more energy efficiency.

Recently, many researches and developments for applying energy-saving actuators to various fields have been conducted. Published Patent Publication No. 2008-0006667 of Doosan Infracore Co., Ltd. relates to a method of controlling a hydraulic pump in a construction machine, and sets a target rotational speed of an engine according to a pressure change amount of a fluid discharged from a hydraulic pump. The electronic pressure reduction proportional valve is controlled according to the difference value obtained by subtracting the actual rotational speed from the target rotational speed of the engine.In this way, the electronic pressure reduction proportional valve is controlled to adjust the discharge flow rate of the hydraulic pump, and the engine is driven at the rated rotational speed. To start.

Japanese Laid-Open Patent Publication No. 2002-330554 of Kobelco Construction Equipment relates to a power control device for a hybrid vehicle equipped with an engine and an electric motor, and a hybrid construction machine with the corresponding power control device. The power output from the generator is converted into direct current. The generator power conversion circuit outputs the direct current to the DC line, the chopper circuit converts the power output from the battery and the condenser into direct current and outputs the direct current to the DC line, and the motor drive circuit drives the motor based on the power supplied through the DC line. The generator power conversion circuit and the chopper circuit are designed so that the voltage of the DC line is maintained almost constant regardless of a change in the required power from the load so that DC power corresponding to the power required from the load can be output through the motor. A power control circuit for controlling is provided.

The present invention is provided with an electric motor and a two-way hydraulic pump integrated driving unit in place of the conventional direction change valve of the hydraulic device, and controls the forward and reverse rotation direction and speed of the electric motor to raise and lower the hydraulic cylinder of the boom, The generator is operated during the descent operation to generate electrical energy to charge the battery boom potential energy regenerative apparatus and method of construction machinery.

In addition, instead of having a separate hydraulic motor on the conventional return line for power generation, an electric motor connected to the hydraulic pump by a hydraulic pump operated by a hydraulic oil flowing from a high pressure line to a low pressure line when the boom descends through a bidirectional hydraulic pump. An object of the present invention is to provide an apparatus and a method for regenerating a boom potential energy of a construction machine to drive a generator by rotating in a reverse direction.

In addition, the contraction of the boom hydraulic cylinder is judged by distinguishing the boom lowering and the excavation, and during excavation, the hydraulic pressure is passed after passing through the hydraulic pump, and the generator does not operate even in the reverse rotation of the electric motor. It is intended to improve the efficiency.

In order to achieve the above object, according to one aspect of the present invention, the electric motor is driven in the reverse direction, in accordance with the control signal input; Two-way hydraulic pump driven in both directions by the electric motor; A large chamber line formed between the two-way hydraulic pump and the large chamber of the boom hydraulic cylinder and through which hydraulic fluid flows; A small chamber line formed between the two-way hydraulic pump and the small chamber of the boom hydraulic cylinder and through which hydraulic fluid flows; A boom hydraulic cylinder including a large chamber and a small chamber and being telescopically driven by hydraulic oil in the large chamber and the small chamber; Forming flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively, and forming a return line and an outlet port connected to the tank, block the return line to the tank when the boom is raised, and the small chamber line and the return when the boom is lowered. A direction control valve unit forming a flow path between lines; A return line through which hydraulic oil is returned to the tank from the outlet port of the directional control valve; A generator that is generated by driving a hydraulic pump reversely driven by hydraulic oil flowing from the high pressure large chamber line to the low pressure small chamber line when the boom is lowered; A battery storing electrical energy generated by a generator; And a main controller configured to output a control signal to drive the electric motor and the direction control valve unit according to a user's operation signal. It is made, including, here it proposes a boom potential energy regeneration device for a construction machine, characterized in that to use the electrical energy stored in the battery when the boom rises.

Preferably, according to another aspect of the present invention, the boom potential energy regeneration device of the construction machine further comprises a pressure sensor for measuring the pressure of the large chamber and the small chamber, the above-described main controller is a boom hydraulic cylinder If the load of the lower chamber is lower than the pressure of the small chamber according to the signal received from the pressure sensor, it is determined that the boom is lowered. If the pressure of the large chamber is smaller than the pressure of the small chamber, it is judged as excavation. Directional control valve portion is characterized in that when forming the flow path between the large chamber line and the return line.

Further preferably, according to another aspect of the present invention, the above-mentioned direction control valve unit: a three-way switching valve for forming the flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively; And a return line and an outlet port connected to the tank and an inlet port connected to the outlet port side of the three-way switching valve, and blocking the return line to the tank when the boom is raised, and a small chamber line through the three-way switching valve when the boom is lowered. A variable relief valve that forms a flow path between the return lines and a large chamber line through the three-way switching valve and a return line between the return lines when excavating, and the return line is configured to supply hydraulic fluid from the outlet port of the variable relief valve to the tank. It is characterized by recovering.

Preferably, also according to another aspect of the present invention, the boom potential energy regeneration device of the construction machine further comprises a logic valve on the large chamber line, the logic valve is controlled by the main controller, the boom It is turned off when it is raised to maintain the up flow path in the large chamber line, and is operated when the boom is lowered and excavated so that the down flow path is maintained in the large chamber line and recovers a part of the working oil to the tank.

Further preferably, according to another aspect of the present invention, the boom potential energy regenerative device of the construction machine includes: a boom lift, a boom on a flow path branched from each of the large chamber line and the small chamber line to a tank; Check valves installed to prevent backflow during lowering and digging; And a relief valve installed to operate to stabilize the circuit in a case where the pressure is larger than each of the large chamber line and the small chamber line.

Preferably, in addition, according to another aspect of the present invention, the electric motor and the generator of the boom potential energy regenerative devices of the construction machine described above is formed as an integrated unit, characterized in that the integrated unit is a motor combined generator. .

In order to achieve the above object, according to another aspect of the invention, (a) receiving a boom operation signal of the user; (b) determining whether the boom hydraulic cylinder is extended or retracted according to the received operation signal; (c) If it is determined in the above step (b) that the extension signal of the boom hydraulic cylinder, the electric motor is driven forward to drive the two-way hydraulic pump, the large boom hydraulic cylinder through a large chamber line connected to the two-way hydraulic pump Supplying the hydraulic oil to the chamber and simultaneously sucking the small chamber of the boom hydraulic cylinder and the hydraulic oil from the tank with the bidirectional hydraulic pump through the small chamber line to extend the boom hydraulic cylinder to raise the boom; (d) When it is determined that the contraction signal of the boom hydraulic cylinder is determined in step (b), the measured pressure signal of the large chamber and the small chamber of the boom hydraulic cylinder is received, and the pressure of the large chamber is larger than the pressure of the small chamber. Determining that the boom is lowered and determining that the pressure of the large chamber is smaller than the pressure of the small chamber is excavation; (e) If it is determined that the excavation in step (d) described above, the bidirectional hydraulic pump is driven in the reverse direction by driving the electric motor in the reverse direction, the high pressure into the small chamber of the boom hydraulic cylinder through the small chamber line connected to the bidirectional hydraulic pump To supply hydraulic fluid to the boom hydraulic cylinder, and at the same time, a part of the hydraulic oil recovered from the large chamber of the boom hydraulic cylinder is sucked into the bidirectional hydraulic pump through the large chamber line, and the other part is returned to the tank through the branch branched from the large chamber line. Shrinking; (f) If it is determined in step (d) that the boom is lowered, the operation of the electric motor is interrupted and the bidirectional hydraulic pump is driven in reverse by the boom position energy, or the hydraulic pressure is reversed by the reverse driving of the electric motor and the boom position energy. The pump is driven in the reverse direction, and the high pressure hydraulic oil recovered from the large chamber of the boom hydraulic cylinder is sucked into the bidirectional hydraulic pump through the large chamber line, and a part of the hydraulic oil is transferred to the small portion of the boom hydraulic cylinder through the small chamber line connected to the bidirectional hydraulic pump. Contracting the boom hydraulic cylinder and lowering the boom by supplying the chamber and recovering a part of the remaining working oil to the tank through a flow path branched from the small chamber line; (g) generating power by driving the generator according to the reverse driving of the bidirectional hydraulic pump by the boom position energy when the boom lowers in the above-mentioned step (f) and storing the generated electrical energy in the battery; And (h) using the energy stored in step (g) to drive the electric motor in step (c), (e) or (f). It proposes a boom potential energy regeneration method for a construction machine comprising a.

Preferred embodiments of the invention include embodiments according to various possible combinations of the above mentioned technical features.

In accordance with the aspect of the present invention is provided with an electric motor and a two-way hydraulic pump integrated drive unit, controlling the forward and reverse rotation direction and speed of the electric motor to raise and lower the hydraulic cylinder of the boom, the generator is operated during the boom lowering operation As a result, electric energy is generated and can be charged by a battery.

In addition, the boom position energy regeneration device of construction machinery that drives the generator by rotating the electric motor connected to the hydraulic pump in the reverse direction by the hydraulic pump operated by the hydraulic oil flowing from the high pressure line to the low pressure line when the boom is lowered through the bidirectional hydraulic pump. And methods.

In addition, the contraction of the boom hydraulic cylinder is judged to be divided into the boom lowering and the excavation, and during excavation, the hydraulic pressure is passed after passing through the hydraulic pump, and the generator does not operate even in the case of reverse rotation of the electric motor. I can improve it.

In addition, the energy saving electric hydraulic circuit according to the present invention has the following advantages. The electric motor can be driven only when necessary to drive the two-way hydraulic pump, which can dramatically reduce energy savings. When potential energy acts as a load, electric motor and generator can be used to regenerate the potential energy of hydraulic cylinder into electric energy. Therefore, a lot of energy can be saved / recycled for the existing hydraulic equipment.

It is apparent that various effects not directly mentioned in accordance with various embodiments of the present invention may be derived by those skilled in the art from various configurations according to embodiments of the present invention.

Embodiments of the present invention for achieving the above object are described with reference to the accompanying drawings. In describing the embodiments, the same reference numerals refer to the same configuration, and additional descriptions that may overlap or limit the meaning of the invention may be omitted in describing the embodiments of the present invention.

The present invention is a drive unit integrated with an electric motor and a two-way hydraulic pump drive the generator at a flow rate recovered by the lowering operation of the construction machine, for example, the boom hydraulic cylinder of the excavator to convert the hydraulic energy into electrical energy to regenerate the energy of the boom hydraulic cylinder It is an energy regeneration system that uses the regenerated energy in the ascending operation, and can be used for equipment such as excavators, wheel loaders, and cranes that load heavy materials of construction machinery heavy equipment and move up and down.

First, the boom potential energy regeneration device for a construction machine according to an aspect of the present invention will be described with reference to the drawings.

1 is a schematic circuit diagram of a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention. 2 to 4 is a schematic circuit diagram showing when the boom rises, the boom slows down and the booms rapidly lowered in the boom potential energy regeneration device of the construction machine according to an embodiment of the present invention.

Referring to FIG. 1, one embodiment of the present invention includes an electric motor 10, a bidirectional hydraulic pump 20, a large chamber line, a small chamber line, a boom hydraulic cylinder 30, a directional control valve part 40, It includes a return line, a generator 60 and a battery 70. In addition, although not shown, the embodiment of the present invention further includes a main controller. Specifically, it is as follows.

The electric motor 10 is driven in the forward and reverse directions according to the control signal input from the main controller (not shown). Preferably, the control by the main controller of the electric motor 10 may be made by controlling the power supply by the main power supply (power supply) 77 for supplying power to the electric motor 10. The direction and speed of rotation are determined by the control signal. The electric motor 10 is operated by receiving power from the main power source (power supply) 77. When the main power source (power supply) 77 is controlled and driven by the main controller, the electric motor 10 is operated by supplying power to the electric motor 10. When the electric motor 10 is driven in the forward direction, the hydraulic fluid is introduced into the large chamber 31 by the bidirectional hydraulic pump 20, so that the rod 35 of the boom hydraulic cylinder 30 is raised and the hydraulic cylinder 30 is When the boom is extended and the electric motor 10 is driven in the reverse direction, since the hydraulic oil flows into the small chamber 33 by the bidirectional hydraulic pump 20, the rod 35 of the boom hydraulic cylinder 30 Is lowered and the hydraulic cylinder 30 is contracted so that the boom is lowered.

Preferably, in one embodiment, although not shown, the electric motor 10 may be formed integrally with the generator 60, for example, may be a motor combined generator.

The bidirectional hydraulic pump 20 is coupled to the electric motor 10 and is driven in both directions according to the rotation direction of the electric motor 10. In addition, the pump capacity is preferably changed in accordance with the rotational speed of the electric motor (10). By providing the bidirectional hydraulic pump 20 and connected to the electric motor 10, it can be controlled simply by controlling the rotational direction and speed of the electric motor 10.

The boom hydraulic cylinder 30 of the construction machine includes a large chamber 31 and a small chamber 33, and is telescopically driven by hydraulic pressure of the hydraulic fluid in the large chamber 31 and the small chamber 33. The large chamber 31 is a lower chamber of the cylinder rod 35, and the small chamber 33 refers to a chamber in which a part of the rod 35 is included. The hydraulic oil in the large chamber 31 and the small chamber 33 extends and drives the boom hydraulic cylinder 30 according to the driving of the bidirectional hydraulic pump 20.

The large chamber line is formed between the two-way hydraulic pump 20 and the large chamber 31 of the boom hydraulic cylinder 30, and the small chamber line is the small chamber 33 of the two-way hydraulic pump 20 and the boom hydraulic cylinder 30. Formed between). In the large chamber line and the small chamber line, hydraulic oil flows by driving the bidirectional hydraulic pump 20 according to the rotation of the electric motor 10. In addition, when the boom is lowered, hydraulic fluid flows into the small chamber 33 in the small chamber line and out of the large chamber 31 in the large chamber line by the potential energy of the boom.

Referring to FIG. 1, the direction control valve unit 40 forms flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively, and forms a return line and an outlet port connected to the tank 50. The operation of the direction control valve unit 40 is controlled by the main controller. Referring to FIG. 2, the direction control valve unit 40 blocks the return line to the tank 50 when the boom is raised, that is, when the boom hydraulic cylinder 30 is extended. 3 and 4, a flow path between the small chamber line and the return line is formed when the boom is lowered, that is, when the boom hydraulic cylinder 30 is contracted.

Preferably, as shown in FIGS. 1 to 4, the direction control valve unit 40 includes a three-way switching valve 41 and a variable relief valve 43. As shown in FIG. 1, the three-way switching valve 41 forms flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively. An inlet port of the variable relief valve 43 is connected to the outlet port side of the three-way switching valve 41, and a return line connected to the tank 50 is connected to the outlet port side of the variable relief valve 43. Accordingly, the operation of the three-way switching valve 41 and the variable relief valve 43 blocks the return line to the tank 50 when the boom is raised, and the three-way switching valve 41 and the variable relief valve when the boom is lowered. A flow path is formed between the small chamber line and the return line through 43).

The return line is formed between the tank 50 from the outlet port of the directional control valve unit 40, and is a flow path for recovering hydraulic oil to the tank 50.

The generator 60 generates power by using potential energy of the boom when the boom is lowered. Specifically, as shown in Figures 3 and 4, the hydraulic pump 20 is driven in the reverse direction by the hydraulic oil flowing from the high pressure large chamber line to the low pressure small chamber line when the boom is lowered. The generator 60 is driven and generated by reverse driving of the hydraulic pump 20. Preferably, at this time, the electric motor 10 connected to the hydraulic pump 20 is driven axially with the power supply cut off, so that the generator 60 connected to the electric motor 10 can generate power, or the hydraulic pump 20 The electric motor 10 connected to the power generator 10 may be accelerated by the flow of the hydraulic oil to be driven by the reverse driving of the hydraulic pump 20 in excess of the reverse driving force by the power source. 3 is a shaft of the electric motor 10 is driven in the reverse direction as the hydraulic pump 20 is driven in the reverse direction by the potential energy due to the boom load without the reverse drive of the electric motor 10 by the power supply when the boom is lowered As the 60 is generated, the regeneration of the potential energy is large, and FIG. 4 shows the reverse direction driving of the hydraulic pump 20 by the boom potential energy in addition to the reverse driving of the electric motor 10 by the power source when the boom is lowered. According to this, the electric motor 10 is accelerated and driven in the reverse direction, indicating that the generator 60 is generated. 3 and 4, the driving of the generator 60 and the driving of the electric motor 10 are determined by the main controller.

Preferably, according to one embodiment of the present invention, although not shown, the electric motor 10 and the generator 60 may be formed as an integrated unit, in which case the integrated unit may be a combined motor generator.

The battery 70 stores electrical energy generated by the generator 60. Referring to FIG. 1, electrical energy generated by the generator 60 is converted into direct current by the AC / DC converter 73 and stored in the battery 70. The electrical energy stored in the battery 70 may be supplied to the main power source 77 through the inverter 75 to be used when the boom is raised, for example. Unlike in FIG. 1, the generated electricity may be directly charged to the battery 70 without the converter 73 by using a DC generator. In addition, in the case of using a DC motor as the electric motor 10, unlike in FIG. 1, the electric energy stored in the battery 70 without the inverter 75 may be directly supplied to the main power (power supply) 77.

Although not shown, the main controller outputs a control signal to drive the electric motor 10, the generator 60, and the direction control valve unit 40 according to a user's manipulation signal, for example, a joystick manipulation signal.

5 is a schematic circuit diagram illustrating an excavation of a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention, Figure 6 is a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention Flow chart showing how to operate.

5 and 6, another preferred embodiment of the present invention will be described. Although not shown, the boom potential energy regeneration device of the construction machine further includes a pressure sensor (not shown) for measuring the pressure of the large chamber 31 and the small chamber 33. The main controller (not shown) receives a signal from a pressure sensor (not shown). When the rod 35 of the boom hydraulic cylinder 30 descends, that is, at the time of contraction of the hydraulic cylinder 30, the main controller (not shown) digging whether the contraction of the hydraulic cylinder 30 is caused by the boom lowering. In order to determine whether or not), the received pressure signal is compared and judged. In this case, when the pressure of the large chamber 31 is higher than the pressure of the small chamber 33, it is determined that the boom is lowered, and when the pressure of the large chamber 31 is smaller than the pressure of the small chamber 33, the digging is performed. To judge.

The rise of the hydraulic cylinder rod 35 in the present invention is the same as the extension of the hydraulic cylinder 30 and the lowering of the hydraulic cylinder rod 35 is used in the same sense as the contraction of the hydraulic cylinder (30). On the other hand, the boom lowering does not correspond to the lowering of the hydraulic cylinder rod 35, that is, the contraction of the hydraulic cylinder 30, or all contractions of the hydraulic cylinder 30 corresponds to the term 'boom lowering' in the present invention, It should be noted that even when the hydraulic cylinder 30 is contracted. In FIG. 6, boom down means lowering of the hydraulic cylinder rod 35, and boom up means raising of the hydraulic cylinder rod 35.

In addition, in the present embodiment, the direction control valve unit 40 forms a flow path between the large chamber line and the return line during excavation. Thus, a portion of the hydraulic oil is recovered to the tank 50 to lower the pressure of the large chamber line.

With reference to Figures 1 to 6 look at another embodiment of the present invention.

Preferably, referring to FIG. 1, the direction control valve unit 40 includes a three-way switching valve 41 and a variable relief valve 43. The three-way switching valve 41 is preferably a three port three position solenoid valve. The three-way switching valve 41 forms flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively, and the variable relief valve 43 is connected to the outlet port side. The outlet port of the variable relief valve 43 is connected to a return line connected to the tank 50. Hydraulic oil is recovered from the outlet port of the variable relief valve 43 to the tank 50 through the return line.

The variable relief valve 43 in this embodiment blocks the return line to the tank 50 when the boom is raised, and forms a flow path between the small chamber line and the return line in cooperation with the three-way switching valve 41 when the boom is lowered. Let's do it. And during excavation, in conjunction with the three-way switching valve 41 to form a flow path between the large chamber line and the return line.

Preferably, also looks at another embodiment of the present invention. 1 to 5, the boom potential energy regeneration device of the construction machine of the present embodiment further comprises a logic valve 80 on the large chamber line. The logic valve 80 is controlled by a main controller (not shown) and is turned off when the boom is raised to maintain the up flow path in the large chamber line, and is operated during the boom lower and excavation to maintain the down flow path in the large chamber line. Ha ha. When the boom is lowered and excavated, a part of the working oil is recovered to the tank 50 through the logic valve 80.

Furthermore, referring to another embodiment of the present invention with reference to Figs. 1 to 5, the boom potential energy regenerative device of a construction machine is a check valve 90 and a relief valve that operates to stabilize the circuit in the case of more than a set pressure. It further comprises 95. Check valves 90 are installed on the flow path connected to the tank 50 branched from the large chamber line and the small chamber line to prevent the reverse flow during the rise of the boom, the lowering of the boom, and the excavation. The relief valve 95 is installed to operate for the stability of the circuit in the case of a pressure higher than each of the large chamber line and the small chamber line. As shown in FIGS. 1 to 5, check valves 90 are installed on the flow path branched from the large chamber line and the small chamber line to the relief valve 95 to prevent backflow in different lines.

Next, a look at the boom potential energy regeneration method of the construction machine according to another aspect of the present invention with reference to the drawings. In describing the specific embodiment of the present invention, the same reference numerals as the reference numerals in the embodiment of the boom potential energy regeneration device of the construction machine refer to the same configuration, and the detailed description thereof refers to the above embodiments.

7 is a flowchart showing a boom potential energy regeneration method of a construction machine according to another embodiment of the present invention, Figure 6 is a method of operating a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention Or a boom potential energy regeneration method for a construction machine.

6 and 7, the method for regenerating boom potential energy of a construction machine according to an embodiment includes the following steps (a) to (h) (S100 to S800).

First, in step (a) (S100), the user receives a boom operation signal. For example, the operation signal of the boom operation lever is received by the main controller (not shown).

In step (S200), it is determined whether the boom hydraulic cylinder 30 extends or contracts according to the operation signal input in step (a).

And in step (c) (S300), if it is determined that the extension signal of the boom hydraulic cylinder 30 in step (b) (S200), the electric motor 10 is driven in a forward direction so that the two-way hydraulic pump 20 is driven. . Accordingly, hydraulic oil is supplied to the large chamber 31 of the boom hydraulic cylinder 30 through the large chamber line connected to the bidirectional hydraulic pump 20 and at the same time, the small chamber 33 and the tank (of the boom hydraulic cylinder 30) are supplied. The hydraulic oil from 50 is sucked into the bidirectional hydraulic pump 20 through the small chamber line. Thus, in step (c) S300, the boom hydraulic cylinder 30 is extended to raise the boom. The bidirectional hydraulic pump 20 here is preferably variable.

Preferably, the return flow path to the tank 50 is blocked by the direction control valve part 40 connected to the flow path and the inlet port branched from the large chamber line and the small chamber line, respectively, in the case of the boom rising. More preferably, the variable relief valve 43 is provided with a variable relief valve 43 connected to an outlet port of a three-way switching valve 41 connected to a flow path and an inlet port branched from the large chamber line and the small chamber line, respectively. By controlling the block the return flow path to the tank (50).

On the other hand, in step (d) (S400), when it is determined that the contraction signal of the boom hydraulic cylinder 30 in step (b) (S200), the large chamber 31 and the small chamber 33 of the boom hydraulic cylinder 30 When the pressure of the large chamber 31 is greater than the pressure of the small chamber 33 when the pressure signal of the large chamber 33 is received, it is determined that the boom is lowered, and the excavation is performed when the pressure of the large chamber 31 is smaller than the pressure of the small chamber 33. Judging by.

And in step (e) (S500), if it is determined that the excavation in step (d) (S400), the electric motor 10 is driven in a reverse direction so that the bidirectional hydraulic pump 20 is driven in the reverse direction. Accordingly, the high pressure hydraulic oil is supplied to the small chamber 33 of the boom hydraulic cylinder 30 through the small chamber line connected to the bidirectional hydraulic pump 20 and simultaneously recovered from the large chamber 31 of the boom hydraulic cylinder 30. A part of the working oil is sucked into the bidirectional hydraulic pump 20 through the large chamber line and the other part is recovered to the tank 50 through a flow path branched from the large chamber line. Thus, the boom hydraulic cylinder 30 is contracted.

In one preferred embodiment, the amount of hydraulic oil recovered to the tank 50 through the branched passage in the large chamber line and the amount of hydraulic oil sucked into the bidirectional hydraulic pump 20 through the large chamber line is determined by the large chamber line and the small chamber line. It can be adjusted by controlling the direction control valve portion 40 is connected to each of the flow path and the inlet port branched from each other, more preferably a three-way switch connected to the flow path and the inlet port branched from the large chamber line and the small chamber line, respectively The hydraulic oil and hydraulic pump 20 having a variable relief valve 43 connected to an outlet port of the valve 41 to control the three-way switching valve 41 and the variable relief valve 43 to be recovered to the tank 50. Adjust the flow rate of hydraulic oil drawn into the

In addition, in step (f) (S600), when it is determined that the boom lowers in step (d) (S400) described above, the bidirectional hydraulic pump 20 is driven backward by the boom position energy by blocking the operation of the electric motor 10. Or the hydraulic pump 20 is reverse driven by reverse driving of the electric motor 10 and boom potential energy. In addition, the high pressure hydraulic oil recovered from the large chamber 31 of the boom hydraulic cylinder 30 is sucked into the two-way hydraulic pump 20 through the large chamber line and a part of the hydraulic oil through the small chamber line connected to the two-way hydraulic pump 20. Is supplied to the small chamber 33 of the boom hydraulic cylinder 30 and a part of the remaining hydraulic oil is recovered to the tank 50 through a flow path branched from the small chamber line. Thus, the boom hydraulic cylinder 30 is contracted and the boom is lowered.

In one preferred embodiment, the hydraulic oil and the small chamber line of the hydraulic oil sucked into the bi-directional hydraulic pump 20 through the large chamber line and discharged to the small chamber line is recovered to the tank 50 through the flow path branched from the small chamber line The amount of the hydraulic oil supplied to the small chamber 33 through the control can be adjusted by controlling the direction control valve unit 40 connected to the inlet port and the flow path branched from the large chamber line and the small chamber line, respectively, more preferably. A three-way switching valve 41 and a variable relief are provided with a variable relief valve 43 connected to an outlet port of a three-way switching valve 41 connected to a flow path and an inlet port branched from the large chamber line and the small chamber line, respectively. The valve 43 is controlled to adjust the flow rates of the hydraulic oil recovered to the tank 50 and the hydraulic oil supplied to the small chamber 33.

And in step (g) (S700) in accordance with the reverse drive of the two-way hydraulic pump 20 by the boom position energy when the boom is lowered in step (f) (S600), the generator 60 is driven to generate and generate electric energy Store at 70. In a preferred embodiment, the electric motor 10 and the generator 60 may be composed of one integrated unit, in this case may be a motor combined generator.

Finally, in step (h) (S800), the electric motor 10 in step (c), (e) or (f) (S300, S500 or S600) using the energy stored in step (g) (S700). Reuse the regenerated boom potential energy.

In a preferred embodiment, the boom potential energy regeneration method of the construction machine may comprise a feature according to each operation of the components of the embodiments of the boom potential energy regeneration device of the construction machine described above.

Embodiments disclosed in the drawings of the present invention will be described in detail.

1 is an electrohydraulic circuit for boom energy regeneration, in which the hydraulic cylinder 30 of the boom is raised and lowered by controlling the forward and reverse rotation direction and speed of the electric motor 10 in place of the directional valve of the conventional hydraulic system. , The generator 60 is operated during the boom lowering operation to generate electrical energy is an electro-hydraulic circuit that can be charged by the battery (70).

2 is a schematic circuit diagram illustrating a boom raising time of a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention, and FIG. 3 is a boom potential energy regeneration of a construction machine according to an embodiment of the present invention. 4 is a schematic circuit diagram illustrating a boom slow lowering time of the apparatus, and FIG. 4 is a schematic circuit diagram illustrating a boom fast lowering time of the boom potential energy regeneration device of a construction machine according to an exemplary embodiment of the present invention.

The present invention is an energy saving and regenerative system applied to construction equipment heavy equipment or hydraulic equipment, in this embodiment, the bidirectional hydraulic pump 20, preferably variable bidirectional hydraulic pump 20 to supply the flow rate and drive it An electric motor 10 constitutes one drive unit. When the hydraulic pump 20 is driven in the right direction (forward direction), the boom hydraulic cylinder 30 is extended. In FIG. 1, a check valve 90 is installed between flow paths branched between the large chamber line and the small chamber line to the tank 50 or flowing out of the tank 50 to prevent backflow when the boom is raised and lowered. When the boom is raised or lowered, the relief valve 95 is installed for the safety of the entire circuit when the large chamber or the small chamber line is above a certain pressure. When the hydraulic pump 20 is driven in the right direction, the boom hydraulic cylinder 30 extends, and when the hydraulic pump 20 is driven in the left direction, the boom hydraulic cylinder 30 contracts. As the boom hydraulic cylinder 30 extends and contracts, the boom is raised and lowered. In the case of contraction of the boom hydraulic cylinder 30, the contraction of the hydraulic cylinder 30 for the boom lowering or excavation is made. The logic valve 80 is installed to raise and lower the boom. The logic valve 80 is turned off when the boom is raised, and the logic valve 80 is turned on when the boom is lowered or excavated. A 3 / 3-way solenoid valve 41 is installed for digging of construction machinery such as excavators and for raising / lowering the boom. The variable relief valve 43 is installed for lowering and digging the boom. The variable relief valve 43 serves to open and close the valve variably according to the pressure. When the boom is raised, the motor 10 is used, and when the boom is lowered, regeneration is performed through potential energy.

The function and operation of the 'boom potential energy regenerative apparatus (system)' of FIG. 1 will be described with reference to FIGS. 1 to 6.

When a signal is applied from the main controller (not shown) to the electric motor 10 by the power supplied from the power supply (main power source) 77, the bidirectional hydraulic pump 20 rotates forward / reversely of the electric motor 10. It works according to the signal. Preferably, the pressure of the joystick lever (not shown) is measured prior to the operation of the electric motor 10, and the measured amount of pressure is proportionally calculated to apply a signal to the electric motor 10. Reset the boom up and down criteria to zero.

If the pressure of the boom operation joystick lever (not shown) is greater than zero, it rises, if it is small, it descends. In the case of rising, as shown in Figure 2, s1 = on, s2 & s3 = off and s4 (variable reel valve) is closed. s1 and s2 are signals applied to operate in the opposite direction from the 3/3 solenoid valve 41, s3 is an operating signal applied to the logic valve 80, and s4 is an operating signal applied to the variable relief valve 43. to be. In so doing, a high pressure hydraulic fluid flows into the large chamber line, a low pressure hydraulic oil flows in the small chamber line, and a check valve 90 from the tank 50 through a flow path connected to the small chamber line side to maintain the high pressure state of the large chamber line. The hydraulic oil is sucked through the hydraulic pump 20 and supplied to the hydraulic pump 20. Set the gain value for the boom rise and control the speed of the electric motor 10 in accordance with the signal of the joystick lever. Since the pressure of the large chamber 31 must be increased when the boom is raised, the speed of the electric motor 10 must be raised. In order to prevent flow from flowing from the large chamber line with the high pressure to the small chamber line with the low pressure, the check valve 90 state of FIG. 1, the on state of s1, and the off state of the logic valve 80 are preferably maintained. . The large chamber 31 needs a large flow rate when the boom is raised, thereby closing the variable relief valve 43 in the small chamber line.

In order to determine the lowering and digging of the boom, the pressure of the small chamber 33 and the large chamber 31 is measured, and when the pressure of the large chamber 31 is high, the pressure is lowered. The case is judged by the excavation work of the excavator.

5 and 6, when excavating s1 = off, s2 & s3 = on and s4 (variable relief valve) is opened. 5 shows the flow rate in the excavation operation. Since the large chamber 31 discharges a large amount of flow, the remaining flow flows into the small chamber 33 and the tank 50. That is, a part of the flow rate exiting from the large chamber 31 flows through the small chamber line via the hydraulic pump 20, and the other part is the 3/3 solenoid valve 41 through the flow path branched from the large chamber line side. ) Is recovered to the tank 50 through the variable relief valve 43. At this time, by adjusting the s4 (variable relief valve), it functions to appropriately adjust the amount flowing to the small chamber 33 and the tank 50. In this case, the variable relief valve 43 is controlled by the main controller (not shown).

Referring to FIG. 5, when the excavation is performed, the pressure of the hydraulic fluid of the small chamber line is high, and the pressure of the small chamber line is kept high by the reverse driving of the electric motor 10, and the generator 60 is not driven.

With reference to FIGS. 3 and 4 and 6 will be described in detail when the boom is lowered. The speed at which the boom is lowered depends on the pressure on the joystick lever. It can be expressed as 'speed when the boom descends = motor speed + speed due to potential energy'. If you want to lower the boom quickly increase the speed of the electric motor 10, so the potential energy regenerative part is less, if you want to lower the boom slowly, the speed of the electric motor 10 is slowed or disappeared, so the potential energy regenerative part is Increases. When the boom is lowered, open s1 & s3 = on, s2 = off, s4 (variable relief valve) a little and set the boom lower gain. The large chamber 31 discharges a large amount of discharged water through the large chamber line to the small chamber line side and flows from the small chamber line side to the small chamber 33 and the tank 50. That is, a part of the flow rate discharged from the hydraulic pump 20 is supplied to the small chamber 33 through the small chamber line and the other part is passed through the 3/3 solenoid valve 41 through the flow path branched from the small chamber line side. The tank 50 is recovered to the tank 50 through the variable relief valve 43. Also in this case, by adjusting the variable relief valve 43, it is possible to appropriately adjust the amount flowing to the small chamber 33 and the tank 50.

3 shows a case of slowly lowering the boom at the time of boom down, and FIG. 4 shows a case of rapidly lowering the boom. In FIG. 3, the boom slowly descends and there is little or no portion by the electric motor 10, and the hydraulic pump 20 is circulated from the large chamber line to the small chamber line by the potential energy of the boom. Since the generator 60 is driven by the reverse driving of 20, the amount of power generation is large. In FIG. 4, in order for the boom to descend quickly, reverse driving by the electric motor 10 is required. Accordingly, the amount of power generated by the generator 60 by the reverse driving of the hydraulic pump 20 is generated in FIG. 3. It becomes smaller than the case.

In the above, the present invention has been described with reference to the preferred embodiments with reference to the accompanying drawings. The accompanying drawings and the foregoing embodiments are described by way of example to help those skilled in the art to understand the present invention. Therefore, various embodiments of the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention, the foregoing embodiments are to be considered as illustrative and not restrictive. Therefore, the scope of the present invention should be interpreted according to the invention described in the appended claims rather than the above-described embodiments, and various modifications, alternatives, and equivalents described by those skilled in the art are described above. It is obvious that it is included in the scope of the.

1 is a schematic circuit diagram of a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention.

2 is a schematic circuit diagram illustrating a boom raising time of a boom potential energy regeneration device of a construction machine according to an exemplary embodiment of the present invention.

Figure 3 is a schematic circuit diagram showing the boom slow down time of the boom potential energy regeneration device of the construction machine according to an embodiment of the present invention.

Figure 4 is a schematic circuit diagram showing the boom rapid lowering time of the boom potential energy regeneration device of the construction machine according to an embodiment of the present invention.

5 is a schematic circuit diagram illustrating an excavation of a boom potential energy regeneration device of a construction machine according to an embodiment of the present invention.

6 is a flowchart illustrating a method of operating a boom potential energy regeneration device for a construction machine according to an embodiment of the present invention.

7 is a flow chart showing a boom potential energy regeneration method of a construction machine according to another embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

10: electric motor 20: bidirectional hydraulic pump

30: boom hydraulic cylinder 31: large chamber

33: small chamber 35: rod

40: direction control valve 41: three-way switching valve

43: variable relief valve 50: tank

60: generator 70: battery

73: converter 75: inverter

77: main power supply 80: logic valve

90: check valve 95: relief valve

Claims (7)

An electric motor driven forward and backward according to a control signal input; A bidirectional hydraulic pump driven in both directions by the electric motor; A large chamber line formed between the hydraulic pump and the large chamber of the boom hydraulic cylinder and through which hydraulic fluid flows; A small chamber line formed between the hydraulic pump and the small chamber of the hydraulic cylinder, through which hydraulic fluid flows; A boom hydraulic cylinder including the large chamber and the small chamber and being stretched and driven by hydraulic oil in the large chamber and the small chamber; Flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively, form a return line and an outlet port connected to the tank, and block the return line to the tank when the boom is raised and the small when the boom is lowered. A direction control valve unit forming a flow path between a chamber line and the return line; A return line through which hydraulic oil recovered from the outlet port flows into the tank; A generator that is driven and generated by the driving of the hydraulic pump reversely driven by hydraulic oil flowing from the large chamber line of high pressure to the small chamber line of low pressure when the boom is lowered; A battery storing electrical energy generated by the generator; A main controller outputting a control signal to drive the electric motor, the generator, and the direction control valve unit according to a user's operation signal; And It comprises a; pressure sensor for measuring the pressure of the large chamber and the small chamber, The electrical energy stored in the battery is used when the boom is raised, The main controller determines that the boom lowers when the pressure of the large chamber is higher than the pressure of the small chamber according to the signal received from the pressure sensor when the load of the hydraulic cylinder is lowered and the pressure of the large chamber is small. If it is less than the pressure in the chamber, it is determined by excavation, And the direction control valve unit forms a flow path between the large chamber line and the return line during excavation. delete The method according to claim 1, The direction control valve unit includes: a three-way switching valve for forming flow paths and inlet ports branched from the large chamber line and the small chamber line, respectively; And an inlet port connected to the outlet port side of the three-way switching valve and a return line and an outlet port connected to the tank, and blocking the return line to the tank when the boom is raised and through the three-way switching valve when the boom is lowered. And a variable relief valve forming a flow path between the small chamber line and the return line and forming a flow path between the large chamber line and the return line through the three-way switching valve when excavating. And the return line recovers hydraulic oil from the outlet port of the variable relief valve to the tank. The regenerative apparatus of claim 1 or 3, wherein It further comprises a logic valve on the large chamber line, The logic valve is controlled by the main controller and is turned off when the boom is raised to maintain the upward flow path in the large chamber line, and is operated when the boom is lowered and excavated to maintain the downward flow path in the large chamber line and a part of the hydraulic oil. The boom potential energy regeneration device of a construction machine, characterized in that for recovering to the tank. The method of claim 1 or 3, wherein the regenerative device is: Check valves which are branched from each of the large chamber line and the small chamber line and installed to prevent a backflow when the boom is raised, the boom is lowered and the excavated on the flow path connected to the tank; And And a relief valve installed to operate for the stability of the circuit when the large chamber line and the small chamber line are each above a set pressure. The method according to claim 1 or 3, The electric motor and the generator is made of an integrated unit, characterized in that the integrated unit is a motor combined generator, boom potential energy regeneration device for a construction machine. (a) receiving a user's boom operation signal; (b) determining whether the boom hydraulic cylinder is extended or retracted according to the received operation signal; (c) If it is determined in step (b) that the extension signal of the boom hydraulic cylinder, the electric motor is driven forward to drive a two-way hydraulic pump, the large of the boom hydraulic cylinder through a large chamber line connected to the hydraulic pump Supplying hydraulic oil to the chamber and simultaneously drawing the small chamber of the boom hydraulic cylinder and the hydraulic oil from the tank with the hydraulic pump through the small chamber line to extend the boom hydraulic cylinder to raise the boom; (d) when it is determined that the contraction signal of the boom hydraulic cylinder is determined in step (b), the measured pressure signal of the large chamber and the small chamber of the hydraulic cylinder is received, and the pressure of the large chamber is greater than the pressure of the small chamber. Determining if the boom is lowered and determining that the pressure of the large chamber is less than the pressure of the small chamber; (e) When it is determined in the step (d) that the excavation, driving the electric motor in a reverse direction to drive the hydraulic pump in the reverse direction, through the small chamber line connected to the hydraulic pump to the small chamber of the boom hydraulic cylinder At the same time, a part of the hydraulic oil recovered from the large chamber of the boom hydraulic cylinder is supplied to the hydraulic pump through the large chamber line and the other portion is recovered to the tank through a flow path branched from the large chamber line. Thereby shrinking the boom hydraulic cylinder; (f) If it is determined in step (d) that the boom is lowered, the operation of the electric motor is interrupted so that the hydraulic pump is driven backward by the boom position energy or by the reverse driving of the electric motor and the boom potential energy. The hydraulic pump is driven in the reverse direction, and the high pressure hydraulic oil recovered from the large chamber of the boom hydraulic cylinder is sucked into the hydraulic pump through the large chamber line and a part of the hydraulic oil through the small chamber line connected to the hydraulic pump Contracting the boom hydraulic cylinder and lowering the boom by supplying a to the small chamber of the boom hydraulic cylinder and recovering a part of the remaining hydraulic fluid to the tank through a flow path branched from the small chamber line; (g) generating power by driving a generator according to the reverse driving of the hydraulic pump by the boom position energy when the boom is lowered in step (f) and storing the generated electrical energy in a battery; And (h) driving the electric motor in step (c), (e) or (f) using the energy stored in step (g); Regeneration method of boom potential energy of construction machinery comprising a.

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