CN108755794B - Hydraulic excavator based on hydraulic-electric composite drive - Google Patents

Abstract

The invention discloses a hydraulic excavator based on hydraulic-electric composite drive. The stick driving circuit of the hydraulic excavator includes at least one electric cylinder, at least one hydraulic-pneumatic auxiliary cylinder, at least one frequency converter, DC/DC converter, and super capacitor. Group, controller, solenoid directional valve, fuel tank, pressure sensor, hydraulic accumulator. The stick drive circuit uses an electric cylinder as the main drive cylinder, which has high control accuracy, energy saving, environmental protection and no pollution; and a hydraulic-pneumatic auxiliary cylinder is added to balance the stick's dead weight, efficiently recover the potential energy beyond the load, assist the stick lift and The auxiliary stick excavation can be effectively applied to the special four-quadrant working conditions of the stick, and has the advantages of energy saving and environmental protection, high energy storage utilization, multiple functions and high cost performance.

Description

Hydraulic excavator based on hydraulic-electric composite drive

technical field

The invention belongs to the field of hydraulic excavators, in particular to a hydraulic excavator based on hydraulic-electric composite drive.

Background technique

At present, more than 95% of excavators have adopted hydraulic control technology, which is characterized by high power density and good operability. However, in actual work, due to the harsh working environment, complex working conditions and drastic changes in load, the working range of the engine changes greatly, resulting in only 35% of the energy utilization rate of the whole system. Especially for the excavator stick, the working conditions are complex, and it needs to work in four quadrants, and the magnitude and direction of the load force change frequently, resulting in a large throttling loss on the control valve, and the energy loss exceeds 30%; The kinetic energy and potential energy are often converted into heat energy and consumed by the throttling of the control valve, which increases the temperature of the oil, shortens the service life of the components, and causes serious energy waste.

In order to improve the energy efficiency of the system, kinetic and potential energy recovery and reuse and direct flow regeneration methods are often used. The Chinese patent with application number CN 101435451A discloses a method and device for recovering potential energy of a hydraulic excavator arm. A hydraulic accumulator is used to recover the potential energy of the excavator arm, and the recovered high-pressure oil is used to drive hydraulic pressure. The motor rotates, thereby driving the generator coaxially connected to the hydraulic motor to generate electricity, and finally the generated electricity is stored in the supercapacitor bank or battery for reuse. In this recycling method, the potential energy needs to be converted into electrical energy many times before it can be finally used, and the energy utilization rate is low. The Chinese patent with the application number CN 108104183 A discloses a hydraulic excavator stick regeneration device and a hydraulic excavator, which communicates the rod cavity and the rodless cavity of the stick hydraulic cylinder. The oil in the rod cavity flows directly to the rodless cavity, realizing the regeneration of the hydraulic oil and reducing the fuel consumption of the system. However, in the process of stick flow regeneration, it is necessary to control the multi-way valve to adjust the back pressure of the stick cavity, and there is still a large throttling loss, and this method has a narrow application range and is not suitable for the four-quadrant working condition of the stick. Regenerating the flow of the stick-less cavity of the stick, the regenerated flow can only be used to drive the stick to descend, and cannot be used to assist excavation, which has great limitations.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides a hydraulic excavator based on hydraulic-electric composite drive. The driving circuit of the stick adopts an electric cylinder as the main drive cylinder, and a hydraulic-pneumatic auxiliary cylinder is added to balance the dead weight of the stick and efficiently recover the overrun. The load potential energy, auxiliary stick lifting and auxiliary stick excavation can be applied to the four-quadrant working condition of the stick. It has the advantages of high energy storage utilization, multiple functions, high cost performance, energy saving and environmental protection.

In order to achieve the above purpose, the present invention adopts the following technical scheme: a hydraulic excavator based on hydraulic-electric composite drive, comprising a traveling body (1), a revolving body (2), the revolving body is installed on the traveling body, and the connection with the revolving body will carry out The boom (4) that rotates in the up and down direction, the boom drive circuit (3) for driving the boom to work, the stick (6) installed at the front end of the boom, the stick drive circuit (5) for driving the stick to work ), a bucket (8) installed at the front end of the stick and a bucket drive circuit (7) used to drive the bucket to work;

The stick drive circuit includes at least one electric cylinder (9), at least one hydraulic-pneumatic auxiliary cylinder (14), at least one frequency converter (10), a DC/DC converter (11), and a super capacitor group (12) , controller (13), electromagnetic reversing valve (15), oil tank (16), pressure sensor (17), hydraulic accumulator (18); the power supply end E of the electric cylinder is connected to the power output stage of the inverter through the power cord Connection, the frequency converter is connected with the DC/DC converter through the DC bus, and the DC/DC converter is connected with the super capacitor group; the rodless cavity of the hydraulic auxiliary cylinder is connected with the B port of the electromagnetic reversing valve through the hydraulic pipeline, and there is a rod. The cavity is connected with the A port of the electromagnetic reversing valve, the C port of the electromagnetic reversing valve is connected with the oil inlet of the hydraulic accumulator and the pressure end of the pressure sensor, and the D port of the electromagnetic reversing valve is connected with the fuel tank; Frequency converter, DC/DC converter, signal terminal F of electric cylinder, signal terminal of pressure sensor, electromagnetic reversing valve connection; the cylinder blocks of electric cylinder and hydraulic-pneumatic auxiliary cylinder are hinged on the boom, and electric cylinder and hydraulic-pneumatic auxiliary cylinder are hinged on the boom. The piston rod of the cylinder is hinged to the stick.

The electric cylinder is powered by the grid or the battery.

The drive motor of the electric cylinder is one of an AC asynchronous motor, a stepping motor, a switched reluctance motor, a DC motor or a servo motor.

The electric cylinder adopts any form of transmission among planetary ball screws, roller screws or trapezoidal screws.

The liquid-pneumatic auxiliary cylinder is a piston-type hydraulic cylinder or a plunger-type hydraulic cylinder.

The hydraulic accumulator is a hydraulic accumulator, or a hydraulic accumulator group composed of two or more hydraulic accumulators.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention adopts an electric cylinder driven by electricity as the main driving cylinder of the stick, which has the advantages of fast response speed, high control precision and high reliability, stable operation and no pollution emission;

2. The present invention adopts the liquid-gas auxiliary cylinder communicated with the hydraulic accumulator to balance the gravitational potential energy of the stick itself, which can significantly reduce the installed power of the electric cylinder and the energy consumption during operation, saving energy and protecting the environment;

3. The present invention adopts the electric cylinder and the hydraulic-pneumatic auxiliary cylinder to efficiently recover the potential energy exceeding the load in the operation of the stick, and directly convert it into electric energy and hydraulic energy, which are respectively stored in the super capacitor bank and the hydraulic accumulator, thereby avoiding excessive energy. The loss caused by the conversion, the energy storage and utilization rate are high;

4. The present invention adopts the electromagnetic reversing valve to control the working chamber of the liquid-gas auxiliary cylinder, and the rod chamber or the rodless chamber of the liquid-gas auxiliary cylinder can be selected as the working chamber to assist the work of the arm according to different working conditions, which can be effectively applied to the arm. Special four-quadrant working conditions;

5. The present invention has various functions, adopts the same set of devices, and realizes the integrated control of balancing the self-weight of the stick, recovering the potential energy beyond the load, assisting the stick lifting and assisting the stick excavation based on the same physical quantity, and has high cost performance.

Description of drawings

Fig. 1 is the appearance structure diagram of the hydraulic excavator of the present invention;

Fig. 2 is the system principle diagram of the stick drive circuit of the present invention;

3 is a system schematic diagram of Embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of a system according to Embodiment 3 of the present invention.

In the figure: 1- Traveling body, 2- Rotary body, 3- Boom drive circuit, 4- Boom, 5- Stick drive circuit, 6- Stick, 7- Bucket drive circuit, 8- Bucket, 9 -Electric cylinder, 10-frequency converter, 11-DC/DC converter, 12-super capacitor bank, 13-controller, 14-hydraulic-pneumatic auxiliary cylinder, 15-electromagnetic reversing valve, 16-fuel tank, 17-pressure sensor , 18 - hydraulic accumulator.

Detailed ways

The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings.

As shown in Fig. 1 and Fig. 2, the hydraulic excavator based on the hydraulic-electric hybrid drive includes a traveling body 1 and a revolving body 2. The revolving body 2 is mounted on the traveling body 1, and is connected to the revolving body 2 to rotate in the vertical direction. The boom 4, the boom drive circuit 3 used to drive the boom 4 to work, the stick 6 installed at the front end of the boom 4, the stick drive circuit 5 used to drive the stick 6 to work, the stick drive circuit 5 installed at the front end of the stick 6 The bucket 8 and the bucket drive circuit 7 for driving the bucket 8 to work; the stick drive circuit 5 includes at least one electric cylinder 9, at least one hydraulic-pneumatic auxiliary cylinder 14, at least one frequency converter 10, DC/ DC converter 11, super capacitor group 12, controller 13, electromagnetic reversing valve 15, fuel tank 16, pressure sensor 17, hydraulic accumulator 18; The inverter 10 is connected with the DC/DC converter 11 through the DC bus, and the DC/DC converter 11 is connected with the super capacitor group 12; the rodless cavity of the hydraulic auxiliary cylinder 14 is connected with the electromagnetic directional valve 15 through the hydraulic pipeline The B port of the electromagnetic reversing valve is connected with the B port, the rod cavity is connected with the A port of the electromagnetic reversing valve 15, the C port of the electromagnetic reversing valve 15 is connected with the oil inlet of the hydraulic accumulator 18 and the pressure end of the pressure sensor 17, and the electromagnetic reversing valve is connected. The D port of 15 is communicated with the oil tank 16; the controller 13 is respectively connected with the frequency converter 10, the DC/DC converter 11, the signal end F of the electric cylinder 9, the signal end of the pressure sensor 17, and the electromagnetic reversing valve 15; The cylinder body of the hydraulic-pneumatic auxiliary cylinder 14 is hinged on the boom 4 , and the electric cylinder 9 and the piston rod of the hydraulic-pneumatic auxiliary cylinder 14 are hingedly connected to the stick 6 .

The electric cylinder 9 is powered by the grid or the battery.

The drive motor of the electric cylinder 9 is one of an AC asynchronous motor, a stepping motor, a switched reluctance motor, a DC motor or a servo motor.

The electric cylinder 9 is driven by any one of a planetary ball screw, a roller screw or a trapezoidal screw.

The liquid-pneumatic auxiliary cylinder 14 is a piston-type hydraulic cylinder or a plunger-type hydraulic cylinder.

The hydraulic accumulator 18 is a hydraulic accumulator, or a hydraulic accumulator group composed of two or more hydraulic accumulators.

Example 1

As shown in FIG. 2 , the stick drive circuit 5 in the hydraulic excavator based on the hydraulic-electric composite drive in this embodiment includes a hydraulic-pneumatic auxiliary cylinder 14 and two electric cylinders 9; the hydraulic-pneumatic auxiliary cylinder 14 is arranged in the In the middle, two electric cylinders 9 are symmetrically arranged on both sides of the hydraulic-pneumatic auxiliary cylinder 14 . The cylinder body end of the hydraulic-pneumatic auxiliary cylinder 14 and the cylinder body ends of the two electric cylinders 9 are coaxially hinged on the boom 4, and the piston rod end of the hydraulic-pneumatic auxiliary cylinder 14 and the piston rod ends of the two electric cylinders 9 are coaxially hinged. Stick 6 on. The rodless cavity of the liquid-gas auxiliary cylinder 14 is communicated with the B port of the electromagnetic reversing valve 15 through the hydraulic pipeline, the rod cavity is communicated with the A port of the electromagnetic reversing valve 15, and the C port of the electromagnetic reversing valve 15 is connected with the hydraulic energy storage. The oil inlet of the valve 18 is communicated with the pressure end of the pressure sensor 17 , and the D port of the electromagnetic reversing valve 15 is communicated with the oil tank 16 . The power supply terminals E of the two electric cylinders 9 are respectively connected with the power output stages of the two frequency converters 10 through the power lines. The capacitor bank 12 is connected. The controller 13 is respectively connected with the signal terminals F of the two electric cylinders 9 , the two frequency converters 10 , the DC/DC converter 11 , the signal terminals of the pressure sensor 17 , and the electromagnetic reversing valve 15 .

Example 2

As shown in FIG. 3 , the stick drive circuit 5 in this embodiment includes two hydraulic and pneumatic auxiliary cylinders 14 and one electric cylinder 9 ; the electric cylinder 9 is arranged in the middle, and the two hydraulic and pneumatic auxiliary cylinders 14 are symmetrically arranged in the electric cylinder On both sides of 9, the cylinder ends of the two hydraulic and pneumatic auxiliary cylinders 14 and the electric cylinder 9 are coaxially hinged on the boom 4, and the piston rod ends of the two hydraulic and pneumatic auxiliary cylinders 14 and the electric cylinder 9 are coaxially hinged on the stick. 6 on. The rodless chambers of the two liquid-gas auxiliary cylinders 14 are connected to the B port of the electromagnetic reversing valve 15 through the hydraulic pipeline, the rod chambers are connected to the A port of the electromagnetic reversing valve 15, and the C port of the electromagnetic reversing valve 15 is connected to the hydraulic valve 15. The oil inlet of the accumulator 18 is communicated with the pressure end of the pressure sensor 17 , and the D port of the electromagnetic reversing valve 15 is communicated with the oil tank 16 . The power supply terminal E of the electric cylinder 9 is connected to the power output stage of the inverter 10 through the power cable. The controller 13 is respectively connected with the signal terminal F of the electric cylinder 9 , the frequency converter 10 , the DC/DC converter 11 , the signal terminal of the pressure sensor 12 , and the electromagnetic reversing valve 15 .

Example 3

As shown in FIG. 4 , the stick drive circuit 5 in this embodiment includes: a hydraulic-pneumatic auxiliary cylinder 14 and an electric cylinder 9; The gas assist cylinder 14 is at the rear. The cylinder end of the electric cylinder 9 and the cylinder end of the hydraulic-pneumatic auxiliary cylinder 14 are hinged front and rear on the boom 4 , and the piston rod end of the electric cylinder 9 and the piston rod end of the hydraulic-pneumatic auxiliary cylinder 14 are hinged front and rear on the arm 6 . The rodless cavity of the liquid-gas auxiliary cylinder 14 is communicated with the B port of the electromagnetic reversing valve 15 through the hydraulic pipeline, the rod cavity is communicated with the A port of the electromagnetic reversing valve 15, and the C port of the electromagnetic reversing valve 15 is connected with the hydraulic energy storage. The oil inlet of the valve 18 is communicated with the pressure end of the pressure sensor 17 , and the D port of the electromagnetic reversing valve 15 is communicated with the oil tank 16 . The power supply terminal E of the electric cylinder 9 is connected to the power output stage of the inverter 10 through the power cable. The controller 13 is respectively connected with the signal terminal F of the electric cylinder 9 , the frequency converter 10 , the DC/DC converter 11 , the signal terminal of the pressure sensor 17 , and the electromagnetic reversing valve 15 .

The above only shows several embodiments of the present invention, and the description is more specific and detailed, but does not limit the protection scope of the present invention. For those skilled in the art, some modifications and improvements made without departing from the concept of the present invention belong to the protection scope of the present invention. Therefore, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be included within the scope of the present invention.

Claims (6)

1. A hydraulic excavator based on a hydraulic-electric composite drive, comprising a traveling body (1) and a revolving body (2), the revolving body is mounted on the traveling body, and a boom (4) that is connected to the revolving body to rotate in an up-down direction, The boom drive circuit (3) used to drive the boom to work, the stick (6) installed at the front end of the boom, the stick drive circuit (5) used to drive the stick to work, the bucket installed at the front end of the stick (8) and the bucket drive circuit (7) used to drive the bucket work, it is characterized in that: The stick drive circuit includes at least one electric cylinder (9), at least one hydraulic-pneumatic auxiliary cylinder (14), at least one frequency converter (10), a DC/DC converter (11), and a super capacitor group (12) , controller (13), electromagnetic reversing valve (15), oil tank (16), pressure sensor (17), hydraulic accumulator (18); the power supply end E of the electric cylinder is connected to the power output stage of the inverter through the power cord Connection, the frequency converter is connected with the DC/DC converter through the DC bus, and the DC/DC converter is connected with the super capacitor group; the rodless cavity of the hydraulic auxiliary cylinder is connected with the B port of the electromagnetic reversing valve through the hydraulic pipeline, and there is a rod. The cavity is connected with the A port of the electromagnetic reversing valve, the C port of the electromagnetic reversing valve is connected with the oil inlet of the hydraulic accumulator and the pressure end of the pressure sensor, and the D port of the electromagnetic reversing valve is connected with the fuel tank; Frequency converter, DC/DC converter, signal terminal F of electric cylinder, signal terminal of pressure sensor, electromagnetic reversing valve connection; the cylinder blocks of electric cylinder and hydraulic-pneumatic auxiliary cylinder are hinged on the boom, and electric cylinder and hydraulic-pneumatic auxiliary cylinder are hinged on the boom. The piston rod of the cylinder is hinged to the stick. 2 . The hydraulic excavator based on hydraulic-electric composite drive according to claim 1 , wherein the electric cylinder is powered by a power grid or a battery. 3 . 3. The hydraulic excavator based on hydraulic-electric composite drive according to claim 1, wherein the drive motor of the electric cylinder is an AC asynchronous motor, a stepping motor, a switched reluctance motor, a DC motor or a servo motor one of the. 4 . The hydraulic excavator based on hydraulic-electric composite drive according to claim 1 , wherein the electric cylinder adopts any one form of planetary ball screw, roller screw or trapezoidal screw for transmission. 5 . 5 . The hydraulic excavator based on hydraulic-electric composite drive according to claim 1 , wherein the hydraulic-pneumatic auxiliary cylinder is a piston-type hydraulic cylinder or a plunger-type hydraulic cylinder. 6 . 6 . The hydraulic excavator based on hydraulic-electric composite drive according to claim 1 , wherein the hydraulic accumulator is one hydraulic accumulator, or two or more hydraulic accumulators. 7 . hydraulic accumulator group.

Images