CN104747544B - Engineering machinery movable arm potential energy variable amplitude energy recovery device - Google Patents

Abstract

The invention relates to an energy recovery device for potential energy and variable amplitude of an engineering machinery boom, comprising a boom oil cylinder, a pressure sensor, a balance valve, a two-position two-way electromagnetic valve, an overflow valve, a three-position four-way electromagnetic reversing valve, and a one-way valve , hydraulic pump, electric motor, oil tank, accumulator, proportional flow valve and controller, the electric motor is connected to the hydraulic pump by mechanical transmission; the hydraulic pump is connected to the oil tank and the one-way valve respectively; The valve, the oil tank, the boom cylinder and the balance valve are connected; the balance valve is connected with the large cavity oil port of the boom cylinder and the two-position two-way solenoid valve; the two-position two-way solenoid valve is connected with the three-position four-way electromagnetic reversing valve; The first relief valve is connected with the three-position four-way electromagnetic reversing valve; the proportional flow valve is connected with the one-way valve, and the oil port of the proportional flow valve is connected with the one-way valve; the third one-way valve is connected with the fourth one-way valve and the accumulator respectively. The pressure sensor is connected with the large chamber oil port of the boom oil cylinder and the accumulator respectively; the second overflow valve is connected with the check valve and the fuel tank respectively; the present invention has energy-saving features, realizes amplitude-changing energy recovery, and has fast dynamic response specialty.

Description

Potential Energy Luffing Energy Recovery Device for Construction Machinery Boom

technical field

The invention relates to a potential energy recovery and regeneration device of a construction machinery boom, in particular to a construction machinery boom potential energy amplitude-changing energy recovery device using an accumulator, which belongs to the technical field of construction machinery.

Background technique

Construction machinery is a kind of engineering and construction machinery products that are widely used. With the continuous increase in the number of construction machinery, the energy consumed by a large number of construction machinery and the pollutants discharged have a serious impact on the environment. Energy-saving and efficient new construction machinery products have become the research and development goals of construction machinery at home and abroad.

During the operation of construction machinery, the mass and inertia of the on-load working device are large, and most of the gravitational potential energy during the lowering process is converted into heat energy, which not only wastes energy, but also increases the temperature of the hydraulic oil, requiring a special hydraulic oil cooler for cooling Hydraulic oil. At the same time, in order to prevent the boom from descending too fast, a throttling speed regulating circuit is usually set up, and a throttle valve is used to adjust the descending speed of the boom cylinder. In this process, more energy is consumed on the throttle valve port, which not only causes energy waste, but also converts a large amount of potential energy into heat energy, which increases fuel consumption, and easily causes the hydraulic system to heat up, reducing the life of the components.

In order to improve the energy saving and reduce emissions of the system, energy recovery and regeneration technology should be considered for the hydraulic system. This can not only save energy and reduce emissions, but also effectively protect the parts and prolong the maintenance and service life of the whole machine. At present, the energy recovery methods of construction machinery mainly include electric type, hydraulic type and electro-hydraulic type combining the two.

Electric energy recovery draws on the concept of the energy recovery system of hybrid vehicles: the remaining potential energy in each action cycle of construction machinery and the remaining kinetic energy of the slewing platform are converted into electrical energy and stored for secondary use through hydraulic motors and generators. application, the utilization rate of energy is further improved, and the purpose of energy saving is achieved. For example, the patent CN1830750A utilizes the motor to recover gravitational potential energy and kinetic energy, and recovers the energy to the battery through the regenerative braking function of the motor connected to the motor. Another example is patent CN102182730A, which converts pressure energy into mechanical energy through a hydraulic motor, and converts mechanical energy into electrical energy through a generator connected to the hydraulic motor, and stores it in a super capacitor to realize potential energy recovery.

However, electrical energy recovery systems have many problems. The first is the high cost of electrical energy storage units such as high-performance batteries and supercapacitors, which limits the practical application of this solution. The second is that the lowering process of the boom takes a very short time, and in the process of a large change in the rotational speed, the power generation of the generator and the charging efficiency of the battery or capacitor are relatively low. The third is that the repeated conversion of mechanical energy, pressure energy, and electrical energy greatly reduces the utilization rate of energy recovery.

Hydraulic energy recovery adopts accumulators as energy storage components. The accumulators can store and release pressure, and its performance is stable, which can meet the requirements of rapid energy saving of construction machinery. For example, patent CN1958972A utilizes an accumulator to directly absorb and directly release gravitational potential energy; patent CN2076972U utilizes an accumulator to indirectly absorb and indirectly release gravitational potential energy through a bidirectional pump/motor. However, the previous hydraulic energy recovery systems have various disadvantages. For example, in the system described in patent CN1958972A, during the process of releasing energy from the accumulator, the pressure drops. The energy in the accumulator cannot be released, resulting in low energy recovery efficiency. As another example, although the system described in the patent CN2076972U can completely release the pressure oil in the accumulator, the direction of rotation of the pump during energy recovery and release is inconsistent. suitable.

Electro-hydraulic energy recovery uses a hybrid energy-saving method of motor regenerative braking and accumulator. For example, the patent CN101408213A uses the accumulator to directly absorb and release energy, and at the same time uses the motor to perform regenerative braking on the bidirectional pump/motor.

Contents of the invention

The purpose of the present invention is to provide an energy recovery device for the potential energy of the boom of construction machinery, which realizes the recovery and utilization of the potential energy of the boom of construction machinery through hydraulic proportional control, improves the efficiency of energy recovery, and protects the hydraulic circuit of the boom of construction machinery. To solve the deficiencies in the above-mentioned background technology.

The technical solution adopted in the present invention is: a device for recovering potential and amplitude-changing energy of the boom of construction machinery, including a boom cylinder 1, a first pressure sensor 2, a second pressure sensor 14, a balance valve 3, and a two-position two-way solenoid valve 4. The first overflow valve 5, the second overflow valve 18, the three-position four-way electromagnetic reversing valve 6, the check valve, the hydraulic pump 8, the electric motor 9, the oil tank 10, the accumulator 13, the proportional flow valve 15 and controller, where:

The motor 9 is mechanically connected to the hydraulic pump 8; the oil inlet of the hydraulic pump 8 is connected to the oil tank 10, and the oil outlet of the hydraulic pump 8 is connected to the oil inlet of the first one-way valve 7; the three-position four-way electromagnetic The P port of the reversing valve 6 is connected with the oil outlet of the first one-way valve 7, the T port of the three-position four-way electromagnetic reversing valve 6 is connected with the oil tank 10, and the A port of the three-position four-way electromagnetic reversing valve 6 is connected with the dynamic The small cavity oil port L of the boom cylinder 1 is connected, the B port of the three-position four-way electromagnetic reversing valve 6 is connected with the I port of the balance valve 3; the H port of the balance valve 3 is connected with the large cavity oil port of the boom cylinder 1 M is connected, the G port of the balance valve 3 is connected with the F port of the two-position two-way solenoid valve 4; the E port of the two-position two-way solenoid valve 4 is connected with the A port of the three-position four-way electromagnetic reversing valve 6; The oil inlet C of the first relief valve 5 is connected with the A port of the three-position four-way electromagnetic reversing valve 6, and the oil outlet D of the first relief valve 5 is connected with the B port of the three-position four-way electromagnetic reversing valve 6. The K oil port of the proportional flow valve 15 is connected with the oil inlet of the second check valve 11 and the third check valve 12 respectively, and the J oil port of the proportional flow valve 15 is connected with the fourth check valve respectively. The valve 16 is connected to the oil outlet of the fifth one-way valve 17; the oil outlet of the second one-way valve 11 is connected with the oil inlet of the fifth one-way valve 17 and the large cavity oil port M of the boom cylinder 1 respectively. connected; the oil outlet of the third one-way valve 12 is respectively connected with the oil inlet of the fourth one-way valve 16 and the oil port N of the accumulator 13; the first pressure sensor 2 is connected with the large The second pressure sensor 14 is connected with the oil port N of the accumulator 13; the oil inlet of the second relief valve 18 is connected with the oil outlet of the first one-way valve 7, and the second pressure sensor 14 is connected with the oil port N of the accumulator 13; The oil outlet of the second relief valve 18 links to each other with the oil tank 10;

The three-position four-way electromagnetic reversing valve 6 has a first on-off electromagnet D1 and a second on-off electromagnet D2, the two-position two-way solenoid valve 4 has a third on-off electromagnet D3, and the proportional flow The valve 15 has a proportional electromagnet B1, and the first on-off electromagnet D1, the second on-off electromagnet D2, the third on-off electromagnet D3 and the proportional electromagnet B1 are respectively connected to the controller.

The basic principle of the energy recovery of the potential energy of the swing arm of the present invention is:

1. In the initial stage of boom lowering, the boom cylinder 1 shrinks by its own weight; the controller controls the second switch type electromagnet D2 to be energized, the first switch type electromagnet D1 to be de-energized, and the three-position four-way electromagnetic reversing valve 6 Working in the right position, the oil in the main circuit enters the small chamber of the boom cylinder 1; the controller controls the third switch type electromagnet D3 to lose power, and the two-position two-way solenoid valve 4 is closed, so that the balance valve 3 is closed, and the controller Control the proportional electromagnet B1 to open the proportional flow valve 15 according to a certain opening, so that the oil in the large chamber of the boom cylinder 1 enters the accumulator 13 through the proportional flow valve 15, which is the energy storage process.

2. When the boom is lowered to a certain level, the gravity is gradually blocked and balanced, and the lowering of the boom cylinder is also blocked. At this time, the controller controls the third switch type electromagnet D3 to be energized, and the two-position two-way solenoid valve 4 is opened, so that The balance valve 3 is opened, the energy storage process of the accumulator 13 ends, and the boom oil cylinder 1 descends to the bottom according to the normal hydraulic circuit.

3. In the initial stage of boom rising, the controller controls the third switching electromagnet D3 to lose power, and the two-position two-way solenoid valve 4 is closed, so that the balance valve 3 is closed. According to the first pressure sensor 2 and the second pressure, the controller The pressure value of the sensor 14 controls the opening time and opening degree of the proportional electromagnet B1. The oil is released from the accumulator 13 and enters the large cavity of the boom cylinder 1 after passing through the proportional flow valve 15 to make the boom rise. This is energy discharge Process; the controller controls the electromagnet D1 to be energized and D2 to be de-energized, the three-position four-way electromagnetic reversing valve 6 works in the left position, and the hydraulic pump 10 can also supply oil to the large chamber of the boom cylinder 1 at the same time.

4. After the boom rises to a certain level, the release capacity of the accumulator will be weakened with the increase of the discharge time. When the pressure value of the second pressure sensor 14 is slightly greater than the value of the first pressure sensor 2, the control The device controls the proportional electromagnet B1 to lose power, closes the proportional flow valve 15, and the energy discharge process of the accumulator 13 ends, and the boom oil cylinder continues to rise to the required position according to the normal hydraulic circuit.

The beneficial effects of the present invention are:

1. Energy-saving effect. The present invention effectively recovers the potential energy of the boom of the construction machinery through the hydraulic accumulator, and releases the recovered energy at the beginning stage of the boom raising, so the energy required for the raising of the boom no longer depends entirely on the hydraulic pump, saving the main hydraulic system energy supply, to achieve the purpose of energy saving.

2. Realized energy recovery of variable amplitude. The present invention mainly adds a proportional flow valve and two pressure sensors to the original circuit, and controls the opening of the proportional flow valve by comparing the pressure values of the two pressure sensors, so as to realize energy recovery of variable amplitude by proportional control. Luffing energy recovery can reduce the system impact caused by large changes in boom speed.

3. Realize system protection. Firstly, the controller controls the flow in the system by controlling the opening of the proportional electromagnet in the proportional flow valve, which can limit the lowering speed of the boom when the cylinder is retracted to avoid excessive lowering speed of the boom; when extending the cylinder, it can also limit the The ascent speed of the boom avoids the too fast rise of the boom due to the strong discharge capacity of the accumulator at the beginning of discharge. Secondly, the pressure in the small cavity of the boom cylinder is limited by the first relief valve 5 , and the outlet pressure of the hydraulic pump is limited by the second relief valve 18 . Finally, the balance valve has an overflow function, and the protection of the large chamber and the accumulator is determined by the setting of the overflow function of the balance valve 3 .

4. High energy recovery efficiency. In terms of energy recovery and utilization, the accumulator is used to directly recover and release energy. Compared with the electric energy recovery method described in the background technology, the potential energy of the boom is converted into pressure energy and stored in the accumulator, which can be directly used without being converted into the kinetic energy of the hydraulic motor and the electric energy of the battery. Less, and the reusable potential energy of the construction machinery boom is recovered to the greatest extent.

5. Fast dynamic response. On the one hand, compared with the electrical energy recovery method, the present invention does not have generator power generation and battery or capacitor charging and discharging process, so energy recovery and release are not restricted by generator power generation and battery or capacitor charging efficiency, even Frequent lifting and lowering of the boom can also effectively realize rapid energy recovery and utilization; Solenoid valves respond quickly, and proportional solenoid valves also have very sensitive opening and closing characteristics. These can effectively ensure the response speed of the boom and the response speed of charging and discharging energy of the accumulator.

6. Good controllability and high degree of automation. The controller judges when the accumulator is charged and when it is discharged according to the movement of the boom and the pressure value of the pressure sensor; the hydraulic circuit can choose to use the accumulator or not, and work according to the ordinary hydraulic circuit . The system function is completely realized by the program control solenoid valve in the controller, the control technology is simple and mature, and it is easy to realize. Therefore, the system has good controllability and high degree of automation.

7. Low system cost. The main components used in the present invention include pressure sensors, balance valves, two-position two-way solenoid valves, overflow valves, three-position four-way electromagnetic reversing valves, one-way valves, accumulators, proportional flow valves, etc., all of which are common Mature hydraulic components not only have high reliability, but also reduce the cost of the whole system. At the same time, because the number of components used is small and the integration degree is high, the energy loss caused by the complexity of the system is reduced.

Description of drawings

Fig. 1 is a schematic diagram of the system schematic diagram of the potential energy luffing energy recovery device of the construction machinery boom.

Fig. 2 is a system schematic diagram of a double-boom oil cylinder excavator arm potential energy luffing energy recovery device system, which is an application example of the present invention on an excavator. Fig. 2 uses an excavator as an example to illustrate the present invention, but the present invention is not limited to use on excavators, and is also applicable to other engineering machinery, such as loaders and the like. The number of boom oil cylinders in the present invention is usually 1 to 2, and for loaders, the number of boom oil cylinders is usually 2; for excavators, the number of boom oil cylinders may be 1 or 2 depending on the model, and a certain double-moving cylinder is used here The boom cylinder excavator is used as an example for illustration, so Fig. 2 includes two identical boom cylinders.

Labels in the figure: 1—boom oil cylinder; 2, 14—respectively the first and second pressure sensors; 3—balance valve; 4—two-position two-way solenoid valve; 5, 18—respectively the first and second overflow flow valve; 6—three-position four-way electromagnetic reversing valve; 7, 11, 12, 16, 17—respectively the first, second, third, fourth and fifth one-way valve; 8—hydraulic pump; 9 —motor; 10—fuel tank; 13—accumulator; 15—proportional flow valve, D1—first switch electromagnet, D2—second switch solenoid, D3—third switch solenoid, B1—proportional solenoid iron.

detailed description

The details of the present invention are given below by describing the embodiments in conjunction with the accompanying drawings.

Example 1:

A kind of typical type of engineering machinery is excavator, has designed the excavator arm potential energy variable amplitude energy recovery system shown in Figure 2 according to the technical scheme provided by the invention, this system is an example of the present invention, but implement the present invention The example of the technical solution is not only this one.

The excavator arm potential energy luffing energy recovery system shown in Figure 2 includes two boom cylinders, two pressure sensors, a balance valve, a two-position two-way solenoid valve, two overflow valves, and a three-position four-way electromagnetic reversing valve , five check valves, hydraulic pump, electric motor, oil tank, accumulator, proportional flow valve and controller.

As shown in Figure 2, two boom cylinders 1, a first pressure sensor 2 and a second pressure sensor 14, a balance valve 3, a two-position two-way solenoid valve 4, a first relief valve 5 and a second relief valve 18 , three-position four-way electromagnetic reversing valve 6, first to fifth check valves, hydraulic pump 8, electric motor 9, oil tank 10, accumulator 13, proportional flow valve 15 and controller (not shown in the figure) .

The motor 9 is connected to the mechanical transmission of the hydraulic pump 8; the oil inlet of the hydraulic pump 8 is connected to the oil tank 10, and the oil outlet of the hydraulic pump 8 is connected to the oil inlet of the first one-way valve 7; the P of the three-position four-way electromagnetic reversing valve 6 The port is connected with the oil outlet of the first one-way valve 7, the T port of the three-position four-way electromagnetic reversing valve 6 is connected with the fuel tank 10, and the A port of the three-position four-way electromagnetic reversing valve 6 is connected with the small cavity of the boom cylinder 1 The oil port L is connected, the B port of the three-position four-way electromagnetic reversing valve 6 is connected with the balance valve I port; the H port of the balance valve 3 is connected with the large cavity oil port M of the boom cylinder 1, and the G port of the balance valve 3 is connected with the The F port of the two-position two-way solenoid valve 4 is connected; the E port of the two-position two-way solenoid valve 4 is connected to the A port of the three-position four-way electromagnetic reversing valve 6; the oil inlet C of the first relief valve 5 is connected to The A port of the three-position four-way electromagnetic reversing valve 6, the oil outlet D of the first relief valve 5 is connected to the B port of the three-position four-way electromagnetic reversing valve 6; the K oil port of the proportional flow valve 15 is connected to the second The one-way valve 11 is connected with the oil inlet of the third one-way valve 12, and the J oil port of the proportional flow valve 15 is connected with the oil outlets of the fourth one-way valve 16 and the fifth one-way valve 17; the second one-way valve The oil outlet of 11 and the oil inlet of the fifth one-way valve 17 are connected with the large chamber oil port M of the boom cylinder 1; the oil outlet of the third one-way valve 12 is connected with the oil inlet of the fourth one-way valve 16 Connected to the oil port N of the accumulator 13; the first pressure sensor 2 is connected to the large chamber oil port M of the boom cylinder 1; the second pressure sensor 14 is connected to the oil port N of the accumulator 13; the second overflow valve The oil inlet of 18 is connected to the oil outlet of the first one-way valve 7, and the oil outlet of the second overflow valve 18 is connected to the oil tank 10.

The three-position four-way electromagnetic reversing valve 6 has two on-off electromagnets, which are the first on-off electromagnet D1 and the second on-off electromagnet D2, which are controlled by the controller; the two-position two-way solenoid valve 4 has a first on-off electromagnet. The three-switch electromagnet D3 is controlled by the controller; the proportional flow valve 15 has a proportional electromagnet B1, which is controlled by the controller.

The working principle of the excavator arm potential energy luffing energy recovery is as follows:

The controller collects the pressure value data of the first pressure sensor 2 and the second pressure sensor 14, and sends a control signal according to the working state of the boom (rising, falling or standing still) to control the first switch type electromagnet D1, the second The on-off of the second switch type electromagnet D2, the third switch type electromagnet D3 and the opening of the proportional electromagnet B1 realize the predetermined movement of the boom, and at the same time realize the charging and discharging of the accumulator, thereby achieving excavation maneuverability. The purpose of arm potential energy luffing energy recovery.

The specific working process is as follows:

1. In the initial stage of excavator boom lowering, the boom cylinder 1 is retracted by its own weight; the controller controls the second switch type electromagnet D2 to be energized, the first switch type electromagnet D1 to be de-energized, and the three-position four-way electromagnetic commutation The valve 6 works in the right position, and the oil in the main circuit enters the small cavity of the boom cylinder 1; the controller controls the third switching electromagnet D3 to lose power, and the two-position two-way solenoid valve 4 is closed, so that the balance valve 3 is closed, and at the same time The controller controls the proportional electromagnet B1 to open the proportional flow valve 15 according to a certain opening degree, so that the oil in the large chamber of the boom cylinder 1 enters the accumulator 13 through the proportional flow valve 15, which is the energy storage process. During this process, the flow path of the oil flowing into the small cavity of the boom cylinder is: oil tank 10 → hydraulic pump 8 → first check valve 7 → three-position four-way electromagnetic reversing valve 6 right position → two boom cylinders 1 small cavity; the flow route of oil flowing into the accumulator is: two boom cylinders 1 large cavity → fifth check valve 17 → proportional flow valve 15 → third check valve 12 → accumulator 13; the energy involved The conversion is mainly to convert the gravitational potential energy of the boom cylinder 1 into the pressure energy of the oil in the accumulator 13 . During this process, the proportional flow valve can act as a speed limiter to prevent the boom from descending too fast.

2. When the boom of the excavator is lowered to a certain level, the gravity is gradually blocked and balanced, and the lowering of the boom cylinder is also blocked; at this time, the controller controls the third switch type electromagnet D3 to be energized, and the two-position two-way solenoid valve 4 is opened. Thus, the balance valve 3 is opened; the controller controls the proportional electromagnet B1 to lose power, the proportional flow valve is closed, and the energy storage process of the accumulator 13 ends; the boom oil cylinder descends to the bottom according to the normal hydraulic circuit. During this process, the flow path of the oil flowing into the small cavity of the boom cylinder is: oil tank 10 → hydraulic pump 8 → first check valve 7 → three-position four-way electromagnetic reversing valve 6 right position → two boom cylinders 1 small cavity; the flow path of oil flowing back to the fuel tank is: two-boom cylinder 1 large cavity → balance valve 3 → three-position four-way electromagnetic reversing valve 6 right position → fuel tank 10; in this process, the energy conversion involved is mainly The electric energy of the electric motor 9 is transformed into the kinetic energy of the hydraulic pump 8, and then transformed into the pressure energy of the oil, and finally becomes the kinetic energy of the lowering of the boom.

3. In the initial stage of the excavator arm rising, the controller controls the third switching electromagnet D3 to lose power, and the two-position two-way solenoid valve 4 is closed, so that the balance valve 3 is closed; at this stage, the boom cylinder 1 is raised The oil comes from two parts. One is that the controller controls the second switching electromagnet D2 to be de-energized, the first switching electromagnet D1 is energized, the three-position four-way electromagnetic reversing valve 6 works in the left position, and the boom cylinder 1 The oil in the small cavity flows back to the oil tank 10 through the left position of the three-position four-way electromagnetic reversing valve 6, and the hydraulic pump 8 supplies the large cavity of the boom cylinder 1 through the left position of the three-position four-way electromagnetic reversing valve 6 and the balance valve 3. The second is that the controller controls the opening time and opening degree of the proportional electromagnet B1 according to the pressure values of the first pressure sensor 2 and the second pressure sensor 14. The large chamber of the arm oil cylinder makes the boom rise, which is the process of discharging energy. During this process, there are two flow paths for oil flowing into the large chamber of boom cylinder 1, one is: accumulator 13→fourth one-way valve 16→proportional flow valve 15→second one-way valve 11→boom Oil cylinder 1 large chamber; the second is: oil tank 10 → hydraulic pump 8 → first one-way valve 7 → three-position four-way electromagnetic reversing valve 6 left position → balance valve 3 → boom cylinder 1 large chamber; oil flow back to oil tank 10 The liquid flow path is: boom oil cylinder 1 small chamber → three-position four-way electromagnetic reversing valve 6 left position → oil tank 10; in this process, the energy conversion involved is mainly the pressure energy of the oil in the accumulator 13 It is transformed into the rising kinetic energy of the boom cylinder 1, and the electric energy of the motor 9 is transformed into the kinetic energy of the hydraulic pump 8, and then converted into the pressure energy of the oil, and finally becomes the kinetic energy of the boom rising; during this process, the energy of the accumulator The energy discharge capability is very strong, and the controller can limit the oil flow rate by controlling the opening of the proportional flow valve 15, thereby preventing the boom from rising too fast.

4. After the boom of the excavator rises to a certain level, the release capacity of the accumulator will be weakened as the discharge time increases. When the pressure value of the second pressure sensor 14 is slightly greater than the value of the first pressure sensor 2 , the controller controls the proportional electromagnet B1 to lose power, close the proportional flow valve 15, the energy discharge process of the accumulator 13 ends, and the boom cylinder continues to rise to the required position according to the normal hydraulic circuit. During this process, the flow path of the oil flowing into the large chamber of the boom cylinder 1 is: oil tank 10 → hydraulic pump 8 → first check valve 7 → three-position four-way electromagnetic reversing valve 6 left position → balance valve 3 → dynamic Boom oil cylinder 1 large cavity; the flow path of oil flowing back to oil tank 10 is: boom oil cylinder 1 small cavity → three-position four-way electromagnetic reversing valve 6 left position → oil tank 10; in this process, the energy conversion involved is mainly The electric energy of the electric motor 9 is converted into the kinetic energy of the hydraulic pump 8, then converted into the pressure energy of the oil, and finally into the kinetic energy of the boom rising.

5. When the arm of the excavator is stationary, the controller controls the first switch type electromagnet D1 to lose power, the second switch type electromagnet D2 to lose power, and the three-position four-way electromagnetic reversing valve 6 works in the neutral position; the controller Control the power-off of the third switching electromagnet D3, and close the two-position two-way solenoid valve 4, so that the balance valve 3 is closed; the controller controls the power-off of the proportional electromagnet B1, and the proportional flow valve is closed; It falls under its own weight, and the arm of the excavator remains stationary.

In each of the above working processes, the first relief valve 5 plays the role of limiting the oil pressure in the small chamber of the boom cylinder 1; the second relief valve 18 is connected after the first one-way valve 7 and plays the role of limiting the pressure of the power source of the system , to protect the entire oil supply system; the balance valve 3 has an overflow function to protect the large chamber of the boom cylinder 1 and the accumulator 13.

The above description is only an example of the application of the present invention in an excavator. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (1)

1. An energy recovery device for boom potential energy luffing of construction machinery, comprising a boom cylinder (1), a first pressure sensor (2), a second pressure sensor (14), a balance valve (3), a two-position two-way electromagnetic Valve (4), first relief valve (5), second relief valve (18), three-position four-way electromagnetic reversing valve (6), one-way valve, hydraulic pump (8), electric motor (9), Fuel tank (10), accumulator (13), proportional flow valve (15) and controller, are characterized in that: The electric motor (9) is mechanically connected to the hydraulic pump (8); the oil inlet of the hydraulic pump (8) is connected to the oil tank (10), and the oil outlet of the hydraulic pump (8) is connected to the first one-way valve (7) The oil inlet is connected; the P port of the three-position four-way electromagnetic reversing valve (6) is connected with the oil outlet of the first check valve (7), and the T port of the three-position four-way electromagnetic reversing valve (6) is connected with the oil outlet of the first check valve (7). The oil tank (10) is connected, the A port of the three-position four-way electromagnetic reversing valve (6) is connected with the small cavity oil port L of the boom cylinder (1), and the B port of the three-position four-way electromagnetic reversing valve (6) is connected with The I port of the balance valve (3) is connected; the H port of the balance valve (3) is connected with the large cavity oil port M of the boom cylinder (1), and the G port of the balance valve (3) is connected with the two-position two-way solenoid valve (4) is connected to the F port; the E port of the two-position two-way electromagnetic valve (4) is connected to the A port of the three-position four-way electromagnetic reversing valve (6); the first overflow valve (5) The oil inlet C is connected to the A port of the three-position four-way electromagnetic reversing valve (6), and the oil outlet D of the first relief valve (5) is connected to the B port of the three-position four-way electromagnetic reversing valve (6). ; The K oil port of the proportional flow valve (15) is connected with the oil inlets of the second check valve (11) and the third check valve (12) respectively, and the J oil port of the proportional flow valve (15) Link to each other with the oil outlet of the fourth check valve (16) and the fifth check valve (17) respectively; The oil outlet of the second check valve (11) is connected with the oil outlet of the fifth check valve (17) The oil inlet is connected with the large chamber oil port M of the boom oil cylinder (1); the oil outlet of the third check valve (12) is respectively connected with the oil inlet of the fourth check valve (16) and the accumulator (13) The oil port N is connected; the first pressure sensor (2) is connected with the large chamber oil port M of the boom oil cylinder (1); the second pressure sensor (14) is connected with the oil of the accumulator (13) The oil inlet of the second overflow valve (18) is connected with the oil outlet of the first check valve (7), and the oil outlet of the second overflow valve (18) is connected with the oil tank (10) connected; The three-position four-way electromagnetic reversing valve (6) has a first switch type electromagnet (D1) and a second switch type electromagnet (D2), and the two-position two-way solenoid valve (4) has a third switch type electromagnet (D2). An electromagnet (D3), the proportional flow valve (15) has a proportional electromagnet (B1), the first on-off electromagnet (D1), the second on-off electromagnet (D2), the third on-off electromagnet (D3) and proportional solenoid (B1) are respectively connected to the controller.