CN104613055A - Hydraulic type energy recovery system for potential energy of boom of excavator - Google Patents

Abstract

An excavator arm potential energy hydraulic energy recovery system includes a variable variable motor, a two variable pump, an accumulator, a control valve, an ECU control unit, a pressure sensor, a rotational speed sensor, a hydraulic cylinder, an oil tank and an engine. Aiming at the waste of a large amount of potential energy of the boom under the drastic change of working conditions of the hydraulic excavator, the invention does not change the hydraulic system and operating performance of the existing excavator, and connects a set of hydraulic energy recovery system in parallel to recover the boom when it is lowered. The released potential energy and the regeneration of the boom flow can improve the fuel consumption of the hydraulic excavator and achieve the purpose of saving energy and reducing consumption.

Description

An excavator arm potential energy hydraulic energy recovery system

【Technical field】

The invention relates to the technical field of energy saving of hydraulic excavators, in particular to an excavator arm potential energy hydraulic energy recovery system using a hydraulic accumulator as an energy storage element and a variable variable motor-variable pump as an energy conversion element.

【Background technique】

During the working process of the hydraulic excavator, the boom swings up and down frequently. The working device of the hydraulic excavator is heavy and has a large inertia. However, during deceleration and braking, a large amount of potential energy of the working device is mostly converted into heat energy at the main valve orifice, which not only causes energy waste, but also leads to an increase in system temperature and a reduction in the life of hydraulic components.

At present, the research on energy recovery is mainly concentrated in the field of automobiles, and the research on energy recovery in the field of construction machinery, especially hydraulic excavators, is still in its infancy, and generally uses electric energy recovery (using supercapacitors or batteries as energy storage components), but due to Battery technologies such as supercapacitors are not yet mature, and excavators with electric energy recovery have not been recognized by the market for a long time; and hydraulic energy recovery using hydraulic accumulators as energy storage components reduces the energy conversion process compared with electric energy recovery. And the power density is high, and the whole is reliable and compact.

Prior art, for example, Chinese invention patent: excavator energy recovery system (application number: CN200910306447.0), it comprises hydraulic cylinder, oil tank, quantitative pump, valve and engine. The key technology is that the quantitative pump is coaxial with the first variable pump and the speed measuring photoelectric encoder. One end of the quantitative pump is connected to the hydraulic cylinder through a reversing valve, and the other end of the quantitative pump is connected to the fuel tank and the hydraulic cylinder in two ways; the first variable pump One end is connected to the fuel tank, and the other end is connected to the accumulator through a reversing valve; the second variable pump is installed coaxially with the engine, one end of the second variable pump is connected to the fuel tank, and the other end is connected to the check valve, and the oil outlet of the check valve is divided into three parts. The first way is connected to the accumulator through the reversing valve, the second way is connected to the hydraulic cylinder through the reversing valve, and the third way is connected to the hydraulic cylinder through the reversing valve. This scheme combines flow regeneration and potential energy recovery, and can realize flow regeneration and energy recovery and reuse at the same time. However, there are three aspects that need to be further improved in this scheme: ① Problems in speed controllability: when the boom begins to descend, the fixed motor-variable pump speed is low, and the response time for the outlet pressure of the variable pump to be established is relatively long. In the interior, the load of the motor is close to 0, and the moment of inertia of the fixed motor-variable pump is very small, and the speed of the fixed motor cannot be controlled by adjusting the displacement of the variable pump, resulting in poor speed stability when it starts; ② In terms of energy recovery efficiency Problems in the aspect: the rotational speed of the energy conversion unit composed of quantitative motor-variable pump depends on the speed at which the boom is lowered. When the speed is low, the rotational speed of the energy conversion unit is low so that its volumetric efficiency is low. The speed of the conversion unit also fluctuates accordingly, resulting in the quantitative motor-variable pump not working in the high-efficiency area, and the system efficiency needs to be further improved; Unstable outlet pressure will cause excessive suction or throttling loss. In addition, the system requires major changes to the traditional excavator hydraulic system, and the operating performance is different from the original system.

In view of this, the inventor conducted in-depth research on the defects of the prior art, and this case was produced.

【Content of invention】

The technical problem to be solved by the present invention is to provide an excavator arm potential energy hydraulic energy recovery system to improve the fuel consumption of the excavator and achieve the purpose of saving energy and reducing consumption.

The present invention is achieved like this:

Excavator arm potential energy hydraulic energy recovery system, including a variable motor (8), two variable pumps (71, 72), accumulators (10), control valves (2, 31, 32, 33, 51, 52, 53, 9, 131, 132, 14, 15), ECU control unit (18), pressure sensor (61, 62, 63, 64), speed sensor (4), hydraulic cylinder (11), fuel tank (1), engine (16);

The variable variable motor (8) is coaxially installed with the first variable pump (71) and the rotational speed sensor (4), the inlet of the variable variable motor (8) is connected in series with the control valve (52), and the variable variable motor (8) ) and the other end is connected to the control valve (51) and the control valve (9) in two ways;

The other end of the control valve (52) is connected to the control valve (9), and the two working oil chambers of the control valve (9) are respectively connected to the upper and lower chambers of the hydraulic cylinder (11);

The inlet of the first variable pump (71) is connected to the oil tank (1), and the other end is divided into two circuits after passing through the control valve (31), the first circuit is connected to the accumulator (10), and the second circuit is connected to the control valve (2) connected to the fuel tank (1);

The engine (16) is coaxially equipped with a second variable pump (72), one end of the second variable pump (72) is connected to the fuel tank (1), and the other end is connected to the control valve (32), and the outlet of the control valve (32) is divided into two channels , the first path is connected to the control valve (33), the second path is connected to the hydraulic cylinder (11) through the control valve (14); the inlet of the control valve (33) is connected to the control valve (53), and the other end of the control valve (53) is connected to the accumulator energy device (10);

The left hydraulic control port of the control valve (14) is connected to the control valve (131), the right hydraulic control port is connected to one end of the control valve (15), and the other end of the control valve (15) is respectively connected to the oil tank (1) and the control valve (132) ;

The control valves (131, 132) are controlled by an operating handle (12), on which an angular displacement sensor (17) is installed, and the angular displacement signal is fed back to the ECU control unit (18);

Pressure sensors (62, 63) are arranged at the inlet and outlet of the control valve (52), pressure sensors (61) are arranged at the outlet of the variable motor (8), and pressure sensors (64) are arranged at the outlet of the accumulator (10);

The pressure signals of the pressure sensors (61, 62, 63, 64) are fed back to the ECU control unit (18), and the ECU control unit (18) controls the variable motor (8), the first variable Pump (71), control valve (9), control valves (51, 52, 53).

Further, the control valves (51, 52, 53) are throttle valves.

Further, the control valve (2) is a relief valve.

Further, the control valves (31, 32, 33) are one-way valves.

Further, the control valves (9, 14, 15) are reversing valves.

Further, the control valves (131, 132) are pilot valves.

The present invention has the advantages of: 1. Coordinated control of the displacement and rotational speed of the variable variable motor-variable pump, making it work in a high-efficiency zone to improve the recovery efficiency of the energy recovery system; 2. Using a pressure sensor to measure the inlet and outlet of the throttle valve Pressure, through the ECU to control the variable motor-the inlet pressure of the motor in the variable pump to compensate the outlet pressure of the throttle valve, so that the pressure difference between the inlet and outlet of the throttle valve remains basically unchanged, and the lowering of the boom is only related to the opening of the throttle valve ;3. Connect a pressure sensor to the outlet of the variable motor, and install a throttle valve in the bypass; when the flow fluctuates, the opening of the throttle valve is automatically adjusted by the ECU, so that the pressure at the motor outlet is basically stable, and all the oil in the upper chamber of the hydraulic cylinder comes from the Based on the motor, flow regeneration can be realized and cavitation in the upper cavity of the hydraulic cylinder can be avoided.

【Description of drawings】

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Fig. 1 is a flowchart of the energy recovery system of the present invention.

Fig. 2 is a schematic diagram of the hydraulic system of the energy recovery system of the present invention.

Fig. 3 is a functional block diagram of the energy recovery system of the present invention.

【Detailed ways】

Please refer to Fig. 1 to Fig. 3, the excavator arm potential energy hydraulic energy recovery system includes a variable variable motor 8, two variable variable pumps 71, 72, accumulator 10, control valves 2, 31, 32, 33, 51 , 52, 53, 9, 131, 132, 14, 15, ECU control unit 18, pressure sensor 61, 62, 63, 64 speed sensor 4, hydraulic cylinder 11, and fuel tank 1, engine 16;

The variable motor 8 is coaxially installed with the first variable pump 71 and the rotational speed sensor 4, the inlet of the variable motor 8 is connected in series with the throttle valve 52, and the other end of the variable motor 8 is divided into two ways to connect the throttle valve 51 and the reversing valve 9 respectively; the throttle valve 52 The other end is connected to the reversing valve 9, and the two working oil chambers of the reversing valve 9 are respectively connected to the upper and lower chambers of the hydraulic cylinder 11; the inlet of the variable pump 71 is connected to the oil tank 1, and the other end is divided into two circuits after passing through the one-way valve 31, the first The road is connected to the accumulator 10, and the second road is connected to the overflow valve 2; a variable pump 72 is installed coaxially with the engine 16, and one end of the variable pump 72 is connected to the fuel tank 1, and the other end is connected to the check valve 32, and the outlet of the check valve 32 is divided into two The first path is connected to the one-way valve 33, and the second path is connected to the hydraulic cylinder 11 through the reversing valve 14; the inlet of the one-way valve 33 is connected to the throttle valve 53, and the other end of the throttle valve 53 is connected to the accumulator 10. The left hydraulic control port of the reversing valve 14 is connected with the pilot valve 131, the right hydraulic control port is connected with one end of the reversing valve 15, and the other end of the reversing valve 15 is respectively connected with the oil tank 1 and the pilot valve 132; 12 to control, install the angular displacement sensor 17 on the joystick 12, and feed back the angular displacement signal to the ECU control unit 18; A sensor 61 and a pressure sensor 64 are arranged at the outlet of the accumulator 10 . The pressure signals of the pressure sensors 61, 62, 63, 64 are fed back to the ECU control unit 18, and the ECU control unit 18 sends commands to control the reversing valve 9, variable motor 8, first variable pump 71, Throttle valves 51, 52, 53.

The energy-saving working principle of the boom energy recovery system is as follows:

1. The energy recovery system is turned off

Each electromagnetic reversing valve or electro-hydraulic reversing valve is in a power-off state, the energy recovery system does not work, and the original boom circuit is maintained.

2. The energy recovery system is on

(1) decentralization

When the joystick 12 is turned to the right (to control the lowering of the boom), the lowering of the boom is recognized by the angular displacement sensor 17, and the opening of the joystick 12 is fed back to the ECU controller 18, and the ECU sends an instruction to energize the valves 9 and 15, and 15 cut off the pilot pressure oil of the control valve 14 of the original system after energizing, and it is in the neutral position under the action of the return spring. The ECU controls the opening of the throttle valve 52 according to the angular displacement fed back by the sensor 17, and at the same time, according to the inlet and outlet pressure feedback of the throttle valve 52, the ECU automatically controls the displacement of the variable pump 71 and the variable motor 8 in the energy conversion unit to realize throttling The pressure difference between the inlet and outlet of the valve 52 is basically unchanged, so that the output flow of the lower chamber of the hydraulic cylinder is only related to the opening degree of the throttle valve 52, and has nothing to do with the frequently fluctuating load, so that the stable speed control when the boom is lowered is realized. The accumulator 10 is filled with liquid through the variable pump 71 in the energy conversion unit to realize energy recovery; a throttle valve 51 and a pressure sensor 6.1 are installed on the outlet side of the variable motor 8, and the other end of the throttle valve 51 is connected to the fuel tank, and through the ECU The control unit 18 automatically adjusts the opening of the throttle valve 51 so that the outlet pressure of the variable motor 8 is basically stable, so that all the oil in the upper chamber of the hydraulic cylinder 11 comes from the lower chamber of the hydraulic cylinder 11 to realize flow regeneration, that is, the hydraulic cylinder under the boom A part of the oil in the cavity is supplied to the upper cavity through the valve 52 and the motor 8, and a part of the return oil is returned to the oil tank 1 through the throttle valve 51.

(2) up

When the control handle 12 is turned to the left (to control the rise of the boom), the signal fed back by the angular displacement sensor 17 recognizes that the boom is rising, and the ECU control unit sends an instruction to cut off the power of the valves 9 and 15, and adjust the opening of the throttle valve 5.3 to Controlling its output flow, the accumulator 10 releases the pressure oil to provide additional high-pressure oil for the system to accelerate the rise of the boom.

Aiming at the waste of a large amount of potential energy of the boom under the drastic change of working conditions of the hydraulic excavator, the invention does not change the hydraulic system and operating performance of the existing excavator, and connects a set of hydraulic energy recovery system in parallel to recover the boom when it is lowered. The released potential energy and the regeneration of the boom flow can improve the fuel consumption of the hydraulic excavator and achieve the purpose of saving energy and reducing consumption.

The ECU control unit controls the charging and discharging of the hydraulic accumulator through the control valve assembly, the expansion and contraction of the hydraulic cylinder of the boom, and the pressure sensor, speed sensor and angular displacement sensor in the sensor assembly respectively collect pressure, speed, and angular displacement signals to control the variable motor. -Variable pump and control valve assembly; the boom hydraulic cylinder drives the boom of the excavator to realize the recovery and reuse of the potential energy of the boom of the excavator; thus achieving the purpose of energy saving.

The present invention adopts hydraulic energy recovery, combined with flow regeneration, uses a hydraulic accumulator as an energy storage element, a variable motor-variable pump as an energy conversion unit and a new boom potential energy recovery system with a series throttle valve. When the boom is lowered initially The speed of lowering the boom is controlled by throttling and speed regulation to improve its stability; when the load fluctuates violently, the ECU collects the speed signal to automatically adjust the displacement of the variable motor and the variable pump to control the speed and make it run in the high-efficiency zone ( High-efficiency zone: controlling the variable variable pump and the variable variable motor have higher efficiency in a certain speed and certain displacement range); in addition, through the ECU to adjust the variable motor - the output torque of the variable pump is to control the inlet pressure of the variable motor. The outlet pressure compensation of the throttle valve keeps the inlet and outlet pressure of the throttle valve basically unchanged, and the speed of lowering the boom is only related to the opening area of the throttle valve, that is, the stability of the lowering speed of the boom is improved on the basis of ensuring energy recovery efficiency sex.

The above descriptions are only preferred implementation examples of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. an excavator swing arm potential energy hydraulic type energy-recuperation system, is characterized in that:

Comprise a variable displacement motor (8), two variable displacement pumps (71,72), accumulator (10), control valve (2,31,32,33,51,52,53,9,131,132,14,15), ECU control unit (18), pressure transducer (61,62,63,64), speed probe (4), oil hydraulic cylinder (11), fuel tank (1), motor (16);

Described variable displacement motor (8) coaxially installs described first variable displacement pump (71) and described speed probe (4), described variable displacement motor (8) import is connected with control valve (52), and described variable displacement motor (8) the other end divides two-way connection control valve (51) and control valve (9) respectively;

Described control valve (52) the other end connection control valve (9), two working oil chambers of control valve (9) connect the upper and lower cavity of described oil hydraulic cylinder (11) respectively;

The import of described first variable displacement pump (71) is connected with fuel tank (1), the other end divides two-way after control valve (31), the first via connects accumulator (10), and the second tunnel connects control valve (2) and is connected to fuel tank (1);

Described motor (16) coaxially installs the second variable displacement pump (72), second variable displacement pump (72) one end connects fuel tank (1), the other end connection control valve (32), the outlet of control valve (32) divides two-way, first via connection control valve (33), the second tunnel is connected with oil hydraulic cylinder (11) by control valve (14); Control valve (33) import connection control valve (53), control valve (53) the other end connects accumulator (10);

The left hydraulic control mouth of control valve (14) is connected with control valve (131), right hydraulic control mouth is connected with control valve (15) one end, and control valve (15) the other end connects fuel tank (1) and control valve (132) respectively;

Control valve (131,132) is controlled by a Joystick (12), at upper installation one angular displacement sensor (17) of described Joystick (12), and angular displacement signal is fed back to ECU control unit (18);

Pressure transducer (62,63) is arranged in the import and export of control valve (52), arrange pressure transducer (61) in the outlet of variable displacement motor (8), arrange pressure transducer (64) in accumulator (10) outlet;

The pressure signal of pressure transducer (61,62,63,64) feeds back to ECU control unit (18), ECU control unit (18), according to gathered signal, distinguishes controlled variable motor (8), the first variable displacement pump (71), control valve (9), control valve (51,52,53) by calculating to send instructions.

2. a kind of excavator swing arm potential energy hydraulic type energy-recuperation system as claimed in claim 1, is characterized in that: described control valve (51,52,53) is throttle valve.

3. a kind of excavator swing arm potential energy hydraulic type energy-recuperation system as claimed in claim 1, is characterized in that: described control valve (2) is relief valve.

4. a kind of excavator swing arm potential energy hydraulic type energy-recuperation system as claimed in claim 1, is characterized in that: described control valve (31,32,33) is one-way valve.

5. a kind of excavator swing arm potential energy hydraulic type energy-recuperation system as claimed in claim 1, is characterized in that: described control valve (9,14,15) is selector valve.

6. a kind of excavator swing arm potential energy hydraulic type energy-recuperation system as claimed in claim 1, is characterized in that: described control valve (131,132) is pilot valve.