CN102635144B - Hydraulic system for loader - Google Patents

Abstract

The invention discloses a loader hydraulic system, which comprises a hydraulic pump, a low-pressure closed oil tank, a high-pressure accumulator, a medium-pressure accumulator and a hydraulic control unit. Wherein, the hydraulic control unit is integrated with a first one-way valve, a second one-way valve, a third one-way valve, a first safety valve, a second safety valve, a third safety valve, a first pressure sensor, a second pressure sensor , the first electromagnetic directional valve, the second electromagnetic directional valve, the third electromagnetic directional valve, the first electromagnetic proportional directional valve, the second electromagnetic proportional directional valve, the third electromagnetic proportional directional valve and the fourth electromagnetic proportional The reversing valve, the present invention utilizes the high-pressure accumulator and the medium-pressure accumulator to store the kinetic energy during the braking process of the loader and the excess energy of the loader under low-load conditions, and uses the low-pressure closed oil tank to store the potential energy during the lowering process of the boom, The purpose of reducing the fuel consumption of the loader and improving the working efficiency of the loader is achieved.

Description

Loader hydraulic system

technical field

The present invention relates to a hydraulic system, more specifically, the present invention relates to a loader hydraulic system. .

Background technique

Loaders are widely used in construction sites such as mines, infrastructure, and road maintenance, mainly for shoveling bulk materials such as earth, rocks, and minerals. Because of its simple and convenient operation, which can save a lot of manpower and improve work efficiency, loaders have become important construction machinery.

In the prior art, the hydraulic system of the loader includes a hydraulic pump, a boom cylinder, a bucket cylinder, a safety valve, an oil filter, a double-acting safety valve, a manual slide valve for the boom, a manual slide valve for the bucket, and an open fuel tank. . The loading operation process includes driving, digging, lifting the boom, lowering the bucket, lowering the boom, etc. to perform cyclic operations. The digging process requires the largest engine load, while the boom lowering process does not require the engine due to the existence of gravitational potential energy. However, the existing loader is still operated by the engine to drive the hydraulic pump to complete the lowering process of the boom, and the potential energy of the falling boom cannot be recovered, and the kinetic energy of the loader cannot be recovered during the braking process, thus reducing the fuel consumption of the loader. High, low loading efficiency.

Contents of the invention

The purpose of the present invention is to overcome the above defects and provide a loader hydraulic system which reduces the fuel consumption of the loader and improves the efficiency of loading operation.

In order to solve the above-mentioned technical problems, the present invention realizes storage, distribution, recovery and release of hydraulic energy by adopting high-pressure accumulator, medium-pressure accumulator, low-pressure closed oil tank and hydraulic control unit, and its technical scheme is:

A loader hydraulic system, including a hydraulic pump, a low-pressure closed oil tank, a high-pressure accumulator, a medium-pressure accumulator, a hydraulic control unit, a boom cylinder, a bucket cylinder, and an oil filter;

The high pressure accumulator adopts piston type or air bag type accumulator, the working pressure of high pressure accumulator is 16~35MPa, the medium pressure accumulator adopts piston type or air bag type accumulator, the working pressure of medium pressure accumulator is 4~15MPa.

The low-pressure closed fuel tank is a closed inflatable fuel tank, and the working pressure of the low-pressure closed fuel tank is 0.5-3MPa.

The hydraulic control unit is integrated with a first one-way valve, a second one-way valve, a third one-way valve, a first safety valve, a second safety valve, a third safety valve, a first pressure sensor, a second pressure sensor, a One electromagnetic reversing valve, the second electromagnetic reversing valve, the third electromagnetic reversing valve, the first electromagnetic proportional reversing valve, the second electromagnetic proportional reversing valve, the third electromagnetic proportional reversing valve and the fourth electromagnetic proportional reversing valve valve, the first pressure sensor and the second pressure sensor, the hydraulic control unit is provided with an internal oil passage, and the hydraulic control unit is also provided with an oil port 6a, an oil port 6b, an oil port 6c, an oil port 6d, and an oil port connected to an external oil circuit. Port 6e, oil port 6f, oil port 6g, oil port 6h, oil port 6i, oil port 6j;

The first electromagnetic reversing valve, the second electromagnetic reversing valve, and the third electromagnetic reversing valve are two-position two-way electromagnetic reversing valves, the first electromagnetic proportional reversing valve, the second electromagnetic proportional reversing valve, the third electromagnetic proportional reversing valve Both the reversing valve and the fourth electromagnetic proportional reversing valve are two-position four-way electromagnetic proportional reversing valves.

The P1 oil port of the first electromagnetic reversing valve communicates with the P2 oil inlet of the first check valve and the 6a oil port of the hydraulic control unit through the internal oil passage of the hydraulic control unit, and the T1 oil port of the first electromagnetic reversing valve Through the internal oil passage of the hydraulic control unit and the 6b oil port of the hydraulic control unit, the T14 oil outlet of the first safety valve, the T12 oil port of the fourth electromagnetic proportional directional valve, and the T4 oil port of the first electromagnetic proportional directional valve , T11 oil port of the third electromagnetic proportional directional valve, T5 oil port of the second electromagnetic proportional directional valve, T10 oil outlet of the second safety valve, P9 oil inlet of the second one-way valve, third safety valve The T8 oil outlet of the third check valve and the P7 oil inlet of the third check valve are connected to each other;

The T2 oil outlet of the first check valve communicates with the P3 oil port of the second electromagnetic directional valve, the P13 oil port of the third electromagnetic directional valve, and the P14 oil port of the first safety valve through the internal oil passage of the hydraulic control unit. connected;

The T3 oil port of the second electromagnetic directional control valve passes through the internal oil passage of the hydraulic control unit and the P4 oil port of the first electromagnetic proportional directional control valve, the P11 oil port of the third electromagnetic proportional directional directional valve, and the 6g oil port of the hydraulic control unit , The 6h oil ports of the hydraulic control unit are connected to each other;

The T13 oil port of the third electromagnetic directional control valve passes through the internal oil passage of the hydraulic control unit and the P12 oil port of the fourth electromagnetic proportional directional directional valve, the P5 oil port of the second electromagnetic proportional directional directional valve, and the 6e oil port of the hydraulic control unit , The 6f oil ports of the hydraulic control unit are connected to each other;

The A4 oil port of the first electromagnetic proportional directional control valve communicates with the B5 oil port of the second electromagnetic proportional directional directional valve and the 6j oil port of the hydraulic control unit through the internal oil passage of the hydraulic control unit, and the B4 oil port of the first electromagnetic proportional directional directional valve The oil port communicates with the A5 oil port of the second electromagnetic proportional directional valve and the 6i oil port of the hydraulic control unit through the internal oil passage of the hydraulic control unit;

The A12 oil port of the fourth electromagnetic proportional reversing valve is connected with the B11 oil port of the third electromagnetic proportional reversing valve, the P8 oil inlet of the third safety valve, and the T7 outlet of the third one-way valve through the internal oil passage of the hydraulic control unit. The oil port and the 6c oil port of the hydraulic control unit are connected with each other, and the B12 oil port of the fourth electromagnetic proportional directional valve is connected with the A11 oil port of the third electromagnetic proportional directional valve and the second safety valve through the internal oil passage of the hydraulic control unit. The P10 oil port, the T9 oil outlet of the second check valve, and the 6d oil port of the hydraulic control unit are connected to each other;

The 6a oil port of the hydraulic control unit communicates with the oil outlet of the hydraulic pump through the hydraulic pipeline, the 6b oil port of the hydraulic control unit communicates with the oil return port of the low-pressure closed oil tank through the hydraulic pipeline, and the 6c oil port of the hydraulic control unit passes through The hydraulic pipeline is connected with the small cavity of the bucket cylinder, the 6d oil port of the hydraulic control unit is connected with the large cavity of the bucket cylinder through the hydraulic pipeline, and the 6e oil port of the hydraulic control unit is connected with the hydraulic detection port of the second pressure sensor , the 6f oil port of the hydraulic control unit communicates with the medium pressure accumulator through the hydraulic pipeline, the 6g oil port of the hydraulic control unit communicates with the hydraulic pressure detection port of the first pressure sensor, and the 6h oil port of the hydraulic control unit communicates with the hydraulic pipeline It communicates with the high-pressure accumulator, the 6i oil port of the hydraulic control unit communicates with the small cavity of the boom cylinder through the hydraulic pipeline, and the 6j oil port of the hydraulic control unit communicates with the large cavity of the boom cylinder through the hydraulic pipeline.

The oil inlet of the hydraulic pump communicates with the oil outlet of the oil filter through the hydraulic pipeline, and the oil inlet of the oil filter communicates with the oil outlet of the low-pressure closed oil tank through the hydraulic pipeline.

Compared with the prior art, the present invention has the advantages of using the high-pressure accumulator and the medium-pressure accumulator to store the excess energy of the loader under low-load conditions, and recovering energy during the lowering of the boom and the unloading of the bucket. The potential energy of boom lowering and bucket unloading is driven by the combination of hydraulic pump and high-pressure accumulator when the boom is rising and the bucket is turning up, which improves the working efficiency of the loader; During the process, the working hydraulic pressure is provided by the medium-pressure accumulator, which can reduce the fuel consumption of the engine and improve the working efficiency of the loader; during the braking process of the loader, the braking energy of the loader is recovered and stored in the high-pressure accumulator; When the operation is intermittent and the forward gear is running without load, the hydraulic energy generated by the engine-driven hydraulic pump is stored in the medium-pressure accumulator, and after the high-pressure accumulator and the medium-pressure accumulator reach the set maximum energy storage pressure, The hydraulic pump is unloaded through the first solenoid directional valve. This can reduce the fuel consumption of the loader and improve the working efficiency of the loader.

Description of drawings

Figure 1 is a diagram of the hydraulic system of the existing loader.

Fig. 2 is a hydraulic system diagram of the loader according to the embodiment of the present invention.

In the figure: 1. The first electromagnetic directional valve, 2. The first one-way valve, 3. The second electromagnetic directional valve, 4. The first electromagnetic proportional directional valve, 5. The second electromagnetic proportional directional valve, 6 .Hydraulic control unit, 7. The third one-way valve, 8. The third safety valve, 9. The second one-way valve, 10. The second safety valve, 11. The third electromagnetic proportional directional valve, 12. The fourth electromagnetic Proportional reversing valve, 13. Third electromagnetic reversing valve, 14. First safety valve, 15. Boom cylinder, 16. High pressure accumulator, 17. First pressure sensor, 18. Medium pressure accumulator, 19 .Second pressure sensor, 20. Bucket oil cylinder, 21. Low pressure closed oil tank, 22. Oil filter, 23. Hydraulic pump, 24. Open oil tank, 25. Bucket joint slide valve, 26. Boom joint slide valve.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is the hydraulic system of the existing loader, including hydraulic pump 23, boom cylinder 15, bucket cylinder 20, first safety valve 14, oil filter 22, bucket manual slide valve 25, boom manual slide valve 26. The second one-way valve 9, the second safety valve 10, the third one-way valve 7, the third safety valve 8 and the open oil tank 24. When the loader is working, the hydraulic pump 23 is driven by the engine, and the bucket oil cylinder 20 is controlled to work by manipulating the bucket manual slide valve 25 to realize bucket shoveling and unloading, and the boom is controlled by manipulating the boom manual slide valve 26 Oil cylinder 15 works to realize the lifting and descending of boom. During the loading operation of the loader, the bucket shovel, unloading, and the lifting and lowering of the boom are completely dependent on the operation of the engine-driven hydraulic pump, which can neither recycle the potential energy during the lowering of the boom, nor recycle the loader. Kinetic energy during braking.

The hydraulic system of the loader according to the embodiment of the present invention shown in Fig. 2 includes a hydraulic pump 23, a low-pressure closed oil tank 21, a high-pressure accumulator 16, a medium-pressure accumulator 18, a hydraulic control unit 6, a boom cylinder 15, and a bucket Oil cylinder 20, oil filter 23, wherein the hydraulic control unit 6 is integrated with the first electromagnetic reversing valve 1, the second electromagnetic reversing valve 3, the third electromagnetic reversing valve 13, the first electromagnetic proportional reversing valve 4, the second electromagnetic reversing valve Second electromagnetic proportional reversing valve 5, third electromagnetic proportional reversing valve 11, fourth electromagnetic proportional reversing valve 12, first check valve 2, second check valve 9, third check valve 7, first safety valve Valve 14, the second safety valve 10, the third safety valve 8, the first pressure sensor 17, the second pressure sensor 19, the hydraulic control unit 6 is provided with an internal oil passage, and the hydraulic control unit 6 is also provided with a connection with the external oil passage. Oil port 6a, oil port 6b, oil port 6c, oil port 6d, oil port 6e, oil port 6f, oil port 6g, oil port 6h, oil port 6i, oil port 6j;

The high-pressure accumulator 16 adopts a piston-type accumulator. The working pressure of the high-pressure accumulator 16 is 18-31.5MPa. _{The maximum} working pressure Pmax of the high-pressure accumulator 16 is 31.5MPa. 17 for testing;

The medium-pressure accumulator 18 adopts an airbag-type accumulator. The working pressure of the medium-pressure accumulator 18 is _5-12MPa . Sensor 19 detects;

The low-pressure closed fuel tank 21 adopts a closed inflatable fuel tank, and the working pressure of the low-pressure closed fuel tank is 0.5-2.5 MPa;

The effect of the first safety valve 14 is to limit the maximum working pressure of the hydraulic pump, and its maximum working pressure is 31.5MPa;

The function of the second safety valve 10 is to prevent the impact of the external load of the bucket during the loading operation, and limit the maximum working pressure of the large cavity of the bucket cylinder 20;

The function of the third safety valve 8 is to prevent the impact of the external load of the bucket during the loading operation, and limit the maximum working pressure of the small chamber of the bucket cylinder 20;

The function of the first one-way valve 2 is to prevent the oil from the high-pressure accumulator 16 and the medium-pressure accumulator 18 from flowing backward to the hydraulic pump 23;

The function of the second one-way valve 9 is: when the boom is lifted to a certain position during the lifting of the boom, the piston rod of the bucket cylinder 20 is pulled out to increase the pressure in the small chamber of the bucket cylinder 20 , the pressure in the small cavity of the bucket oil cylinder 20 is released through the second safety valve, and the large cavity of the bucket oil cylinder 20 can be filled with oil through the second check valve to eliminate the vacuum in the large cavity of the bucket oil cylinder 20;

The function of the third one-way valve 7 is: when the bucket oil cylinder 20 is unloading, when the bucket crosses the lower twist point, it quickly replenishes oil to the lower cavity of the bucket cylinder 20, and hits the limit block to realize bucket unloading;

The first electromagnetic reversing valve 1 is a two-position two-way electromagnetic reversing valve, which is used for unloading control of the hydraulic pump 23;

The second electromagnetic reversing valve 3 is a two-position two-way electromagnetic reversing valve, which is used for energy storage control of the high-pressure accumulator 16 and supply control of working hydraulic oil;

The third electromagnetic reversing valve 13 is a two-position, two-way electromagnetic reversing valve, which is used for energy storage control of the medium pressure accumulator 18;

The first electromagnetic proportional reversing valve 4 is a two-position four-way electromagnetic proportional reversing valve, which is used for lifting control of the boom cylinder 15;

The second electromagnetic proportional reversing valve 5 is a two-position four-way electromagnetic proportional reversing valve, which is used for lowering control of the boom cylinder 15;

The third electromagnetic proportional reversing valve 11 is a two-position four-way electromagnetic proportional reversing valve, which is used for the shoveling control of the boom arm oil cylinder 20;

The fourth electromagnetic proportional reversing valve 12 is a two-position four-way electromagnetic proportional reversing valve, which is used for the unloading control of the boom arm oil cylinder 20;

The P1 oil port of the first electromagnetic reversing valve 1 communicates with the P2 oil inlet of the first check valve 2 and the 6a oil port of the hydraulic control unit 6 through the internal oil passage of the hydraulic control unit 6. The first electromagnetic reversing valve The T1 oil port of 1 passes through the internal oil passage of the hydraulic control unit 6 and the 6b oil port of the hydraulic control unit 6, the T14 oil outlet of the first safety valve 14, the T12 oil port of the fourth electromagnetic proportional reversing valve 12, the first The T4 oil port of the electromagnetic proportional directional control valve 4, the T11 oil port of the third electromagnetic proportional directional directional valve 11, the T5 oil port of the second electromagnetic proportional directional directional valve 5, the T10 oil port of the second safety valve 10, the second single The P9 oil port of the directional valve 9, the T8 oil port of the third safety valve 8, and the P7 oil port of the third one-way valve 7 are connected to each other;

The T2 oil port of the first check valve 2 passes through the internal oil passage of the hydraulic control unit 6 and the P3 oil port of the second electromagnetic reversing valve 3, the P13 oil port of the third electromagnetic reversing valve 13, and the first safety valve 14. The P14 oil ports are connected to each other;

The T3 oil port of the second electromagnetic reversing valve 3 passes through the internal oil passage of the hydraulic control unit 6 and the P4 oil port of the first electromagnetic proportional reversing valve 4, the P11 oil port of the third electromagnetic proportional reversing valve 11, and the hydraulic control unit The 6g oil port of 6 and the 6h oil port of the hydraulic control unit 6 are connected to each other;

The T13 oil port of the third electromagnetic reversing valve 13 passes through the internal oil passage of the hydraulic control unit 6 and the P12 oil port of the fourth electromagnetic proportional reversing valve 12, the P5 oil port of the second electromagnetic proportional reversing valve 5, and the hydraulic control unit The 6e oil port of 6 and the 6f oil port of the hydraulic control unit 6 are connected to each other;

The A4 oil port of the first electromagnetic proportional directional valve 4 communicates with the B5 oil port of the second electromagnetic proportional directional valve 5 and the 6j oil port of the hydraulic control unit 6 through the internal oil passage of the hydraulic control unit 6. The B4 oil port of the directional valve 4 communicates with the A5 oil port of the second electromagnetic proportional directional control valve 5 and the 6i oil port of the hydraulic control unit 6 through the internal oil passage of the hydraulic control unit 6;

The A12 oil port of the fourth electromagnetic proportional reversing valve 12 passes through the internal oil passage of the hydraulic control unit 6 and the B11 oil port of the third electromagnetic proportional reversing valve 11, the P8 oil inlet of the third safety valve 8, the third one-way The T7 oil outlet of the valve 7 and the 6c oil port of the hydraulic control unit 6 are connected to each other, and the B12 oil port of the fourth electromagnetic proportional reversing valve 12 is connected to the third electromagnetic proportional reversing valve 11 through the internal oil passage of the hydraulic control unit 6. The A11 oil port, the P10 oil port of the second safety valve 10, the T9 oil outlet of the second check valve 9, and the 6d oil port of the hydraulic control unit 6 are connected to each other;

The 6a oil port of the hydraulic control unit 6 communicates with the oil outlet of the hydraulic pump 23 through the hydraulic pipeline, the 6b oil port of the hydraulic control unit 6 communicates with the oil return port of the low-pressure closed oil tank 21 through the hydraulic pipeline, and the hydraulic control unit 6 The 6c oil port of the hydraulic control unit 6 communicates with the small chamber of the bucket cylinder 20 through the hydraulic pipeline, the 6d oil port of the hydraulic control unit 6 communicates with the large cavity of the bucket cylinder 20 through the hydraulic pipeline, and the 6e oil port of the hydraulic control unit 6 communicates with the first The hydraulic pressure detection ports of the two pressure sensors 21 are connected, the 6f oil port of the hydraulic control unit 6 is connected with the medium pressure accumulator 18, the 6g oil port of the hydraulic control unit 6 is connected with the hydraulic pressure detection port of the first pressure sensor 17, and the hydraulic pressure The 6h oil port of the control unit 6 communicates with the high-pressure accumulator 16 through the hydraulic pipeline, the 6i oil port of the hydraulic control unit 6 communicates with the small cavity of the boom cylinder 15 through the hydraulic pipeline, and the 6j oil port of the hydraulic control unit 6 passes through The hydraulic pipeline communicates with the large cavity of the boom oil cylinder 15 .

The oil inlet of the hydraulic pump 23 communicates with the oil outlet of the oil filter 22 through the hydraulic pipeline, and the oil inlet of the oil filter 22 communicates with the oil outlet of the low-pressure closed oil tank 21 through the hydraulic pipeline.

The working process of the loader hydraulic system of this embodiment of the invention will be further described below:

The working process of boom lifting is: control the energization of the electromagnet of the first electromagnetic proportional reversing valve 4 and adjust the size of its energized current. The flow out of the energy device 16 passes through the 6h oil port of the hydraulic control unit 6, the P4 oil port of the first electromagnetic proportional reversing valve 4, the A4 oil port, the internal oil passage of the hydraulic control unit 6, and the 6j oil port of the hydraulic control unit 6. , enter the large cavity of the boom cylinder 15 through the hydraulic pipeline to lift the boom, and the lifting speed of the boom can be adjusted by changing the energizing current of the first electromagnetic proportional reversing valve 4, while the small cavity of the boom cylinder 15 Under the action of the oil cylinder piston, the oil passes through the 6i oil port of the hydraulic control unit 6, the B4 oil port, the T4 oil port of the first electromagnetic proportional reversing valve 4, and the 6b oil port of the hydraulic control unit 6, and passes through the hydraulic pipeline. Enter the low-pressure closed oil tank 21; at the same time, the electromagnet of the second electromagnetic reversing valve 3 is energized, and after the electromagnet of the second electromagnetic reversing valve 3 is energized, the high-pressure hydraulic oil from the hydraulic pump 23 passes through the check valve 2, After the P3 and T3 oil ports of the second electromagnetic reversing valve 3, it merges with the high-pressure hydraulic oil flowing out of the high-pressure accumulator 16, and enters the boom cylinder 15 through the P4 and A4 oil ports of the first electromagnetic proportional reversing valve 4. The large cavity enables the lifting speed of the boom to be accelerated without increasing the engine load and the rotating speed of the hydraulic pump 23 during the lifting of the boom.

The working process of boom lowering is: control the energization of the electromagnet of the second electromagnetic proportional reversing valve 5 and adjust the size of its energized current. The flow out of the energy device 18, through the 6f oil port of the hydraulic control unit 6, and the P5 and A5 oil ports of the second electromagnetic proportional reversing valve 5, enters the small cavity of the boom cylinder 15, so that the boom is lowered, and the lowering speed of the boom can be adjusted by changing The size of the electromagnet energizing current of the second electromagnetic proportional reversing valve 5 is adjusted, and the oil in the large chamber of the boom oil cylinder 15 passes through the 6j oil port of the hydraulic control unit 6 and the second electromagnetic proportional oil under the action of the oil cylinder piston. After the B5 oil port of the reversing valve 5, the T5 oil port, and the 6b oil port of the hydraulic control unit 6, it enters the low-pressure closed oil tank 21 through the hydraulic pipeline; After passing through the B5 oil port and T5 oil port of the second electromagnetic proportional reversing valve 5, it enters the low-pressure closed oil tank 21, and the low-pressure closed oil tank 21 is a closed air-filled oil tank, so that the inflation pressure of the low-pressure closed oil tank 21 rises High, so that the gravitational potential energy in the process of lowering the boom can be stored in the low-pressure closed oil tank 21 in the form of gas pressure potential energy. At the same time, the second electromagnetic reversing valve 3 is energized, and the high-pressure hydraulic oil from the hydraulic pump 23 enters the high-pressure accumulator 16 through the check valve 2 and the P3 and T3 oil ports of the second electromagnetic reversing valve 3, and the hydraulic pump The high-pressure hydraulic oil produced at 23 is stored in the high-pressure accumulator 16 to store the energy of the engine and the hydraulic pump. In this way, not only the gravitational potential energy during the lowering of the boom can be recovered and stored in the low-pressure closed oil tank 21 , but also the energy during the operation of the engine and the hydraulic pump 23 can be stored in the high-pressure accumulator 16 .

The working process of turning the bucket up is: control the energization of the solenoid valve iron of the third electromagnetic proportional reversing valve 11 and adjust the size of its energized current. The high-pressure accumulator 16 flows out, passes through the 6h oil port of the hydraulic control unit 6, the P11 oil port of the third electromagnetic proportional reversing valve 11, and the A11 oil port and enters the large chamber of the bucket oil cylinder 20, so that the bucket rotates upwards and turns The speed of bucket upward rotation can be adjusted by changing the electromagnet energizing current of the third electromagnetic proportional reversing valve 11, and the oil in the small chamber of the bucket oil cylinder 20 passes through the 6c oil of the hydraulic control unit 6 in sequence under the action of the piston of the oil cylinder. port, the B11 oil port of the third electromagnetic proportional reversing valve 11, the T11 oil port, and the 6b oil port of the hydraulic control unit 6 enter the low-pressure closed oil tank 21; at the same time, the electromagnet that controls the second electromagnetic reversing valve 3 is energized , when the electromagnet of the second electromagnetic reversing valve 3 is energized, the high-pressure hydraulic oil from the hydraulic pump 23 passes through the check valve 2, the P3 oil port and the T3 oil port of the second electromagnetic reversing valve 3, and the high-pressure energy storage The high-pressure hydraulic oil flowing out of the device 16 merges into the large cavity of the bucket oil cylinder 20, so that the speed of the bucket's upward rotation can be accelerated without increasing the engine load during the upward rotation of the bucket.

The working process of the bucket turning down is to control the energization of the electromagnet of the fourth electromagnetic proportional reversing valve 12 and adjust the size of its energized current. The accumulator 18 flows out, passes through the 6f oil port of the hydraulic control unit 6, the P12 and A12 oil ports of the fourth electromagnetic proportional reversing valve 12, and the 6c oil port of the hydraulic control unit 6, and enters the bucket oil cylinder 20 through the hydraulic pipeline. The small cavity of the rotary bucket makes the bucket turn down to unload, and the oil in the large cavity of the bucket cylinder 20, under the action of the cylinder piston, passes through the 6d oil port of the hydraulic control unit 6 and the B12 of the fourth electromagnetic proportional reversing valve 12 in sequence. The oil port, the T12 oil port, and the 6b oil port of the hydraulic control unit 6 enter the low-pressure closed oil tank 21. Since the low-pressure closed oil tank 21 is a closed air-filled oil tank, the low-pressure closed oil tank 21 is The inflation pressure increases, so that the gravitational potential energy in the process of turning the bucket down can be stored in the low-pressure closed oil tank 21 in the form of gas pressure potential energy; The high-pressure hydraulic oil enters the high-pressure accumulator 16 through the P3 and T3 oil ports of the check valve 2 and the second electromagnetic reversing valve 3, and stores the high-pressure hydraulic oil generated by the hydraulic pump 23 in the high-pressure accumulator 18 to store the engine and hydraulic pump energy. In this way, not only the gravitational potential energy in the process of turning the bucket down can be recovered and stored in the low-pressure closed oil tank 21 , but also the energy during the operation of the engine and hydraulic pump 23 can be stored in the high-pressure accumulator 18 .

The working process of the medium-pressure accumulator 18 energy storage is: when the loader loader is intermittently loading and traveling with no load in the forward gear, when the pressure detected by the second pressure sensor 19 is less than the maximum working pressure _Pmax of the medium-pressure accumulator 18 =12MPa, control the electromagnet of the third electromagnetic reversing valve 13 to be energized, after the electromagnet of the third electromagnetic reversing valve 13 is energized, the hydraulic oil is pumped from the oil outlet of the hydraulic pump 23, and passes through the check valve 2, The P13 and T12 oil ports of the third electromagnetic reversing valve 13 enter the medium-pressure accumulator 18 to increase the pressure of the medium-pressure accumulator 18 and store pressure energy in the medium-pressure accumulator 18 .

The working process of braking energy recovery is: when the loader brakes, the electromagnet that controls the second electromagnetic reversing valve 3 is energized, and after the electromagnet of the second electromagnetic reversing valve 3 is energized, the hydraulic oil is discharged from the hydraulic pump 23 Port pumped out, through the check valve 2, the P3 and T3 oil ports of the second electromagnetic reversing valve 3 into the high-pressure accumulator 18, so that the pressure of the high-pressure accumulator 18 increases, and the kinetic energy of the loader is converted into air pressure potential energy Stored in the high-pressure accumulator 18; when the detection pressure of the first pressure sensor 17 is equal to the highest working pressure _Pmax =31.5MPa of the high-pressure accumulator 16 and the pressure detected by the second pressure sensor 19 is less than that of the medium-pressure accumulator 18 When _{max=12MPa in} the highest working pressure P, the electromagnet controlling the third electromagnetic reversing valve 13 is energized, and after the electromagnet of the third electromagnetic reversing valve 13 is energized, the hydraulic oil flows out from the oil outlet of the hydraulic pump 23, followed by Through the P13 oil port and T13 oil port of the first one-way valve 2 and the third electromagnetic reversing valve 13 , it enters the medium-pressure accumulator 18 and stores part of the braking energy in the medium-pressure accumulator 18 .

The working process of the hydraulic pump unloading is: when the detection pressure of the first pressure sensor 17 is equal to the highest working pressure _Pmax =31.5MPa of the accumulator 16 and the pressure detected by the second pressure sensor 19 is equal to the pressure of the medium pressure accumulator 18 When the maximum working pressure P is _max =12MPa, the solenoid valve controlling the first electromagnetic reversing valve 1 is energized, and the hydraulic oil pumped out by the hydraulic pump 23 passes through the P1 oil port, T1 oil port, and hydraulic control of the first electromagnetic reversing valve 1. The oil passage and 6b oil port of the unit 6 pass through the low-pressure closed oil tank 21 of the hydraulic pipeline to unload the hydraulic pump 23 .

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and can also be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Variations.

Claims (14)

1. a loader hydraulic system, comprise hydraulic pump (23), low pressure sealed reservoir (21), high pressure accumulator (16), intermediate-pressure accumulator (18), hydraulic control unit (6), boom cylinder (15), rotary ink tank (20), oil filter (22), it is characterized in that:

Described hydraulic control unit (6) integrated installation has the first one way valve (2), the second one way valve (9), the 3rd one way valve (7), the first safety valve (14), the second safety valve (10), the 3rd safety valve (8), the first pressure sensor (17), the second pressure sensor (19), the first solenoid operated directional valve (1), the second solenoid operated directional valve (3), the 3rd solenoid operated directional valve (13), the first solenoid-operated proportional reversal valve (4), the second solenoid-operated proportional reversal valve (5), the 3rd solenoid-operated proportional reversal valve (11) and the 4th solenoid-operated proportional reversal valve (12), hydraulic control unit (6) is provided with inner oil duct, and hydraulic control unit (6) is also provided with the hydraulic fluid port 6a being connected with outside oil circuit, hydraulic fluid port 6b, hydraulic fluid port 6c, hydraulic fluid port 6d, hydraulic fluid port 6e, hydraulic fluid port 6f, hydraulic fluid port 6g, hydraulic fluid port 6h, hydraulic fluid port 6i, hydraulic fluid port 6j,

The P1 hydraulic fluid port of described the first solenoid operated directional valve (1) is by the inside oil duct of hydraulic control unit (6) and the P2 oil-in of the first one way valve (2), the 6a hydraulic fluid port of hydraulic control unit (6) is interconnected, the T1 hydraulic fluid port of the first solenoid operated directional valve (1) is by the inside oil duct of hydraulic control unit (6) and the 6b hydraulic fluid port of hydraulic control unit (6), the T14 oil-out of the first safety valve (14), the T12 hydraulic fluid port of the 4th solenoid-operated proportional reversal valve (12), the T4 hydraulic fluid port of the first solenoid-operated proportional reversal valve (4), the T11 hydraulic fluid port of the 3rd solenoid-operated proportional reversal valve (11), the T5 hydraulic fluid port of the second solenoid-operated proportional reversal valve (5), the T10 oil-out of the second safety valve (10), the P9 oil-in of the second one way valve (9), the T8 oil-out of the 3rd safety valve (8), the P7 oil-in of the 3rd one way valve (7) is interconnected,

The T2 oil-out of described the first one way valve (2) is interconnected by the inside oil duct of hydraulic control unit (6) and the P3 hydraulic fluid port of the second solenoid operated directional valve (3), the P13 hydraulic fluid port of the 3rd solenoid operated directional valve (13), the P14 hydraulic fluid port of the first safety valve (14);

The T3 hydraulic fluid port of described the second solenoid operated directional valve (3) is interconnected by the inside oil duct of hydraulic control unit (6) and the P4 hydraulic fluid port of the first solenoid-operated proportional reversal valve (4), the P11 hydraulic fluid port of the 3rd solenoid-operated proportional reversal valve (11), the 6g hydraulic fluid port of hydraulic control unit (6), the 6h hydraulic fluid port of hydraulic control unit (6);

The T13 hydraulic fluid port of described the 3rd solenoid operated directional valve (13) is interconnected by the inside oil duct of hydraulic control unit (6) and the P12 hydraulic fluid port of the 4th solenoid-operated proportional reversal valve (12), the P5 hydraulic fluid port of the second solenoid-operated proportional reversal valve (5), the 6e hydraulic fluid port of hydraulic control unit (6), the 6f hydraulic fluid port of hydraulic control unit (6);

The A4 hydraulic fluid port of described the first solenoid-operated proportional reversal valve (4) is communicated with by the 6j hydraulic fluid port of the inside oil duct of hydraulic control unit (6) and the B5 hydraulic fluid port of the second solenoid-operated proportional reversal valve (5), hydraulic control unit (6), and the B4 hydraulic fluid port of the first solenoid-operated proportional reversal valve (4) is interconnected by the 6i hydraulic fluid port of the inside oil duct of hydraulic control unit (6) and the A5 hydraulic fluid port of the second solenoid-operated proportional reversal valve (5), hydraulic control unit (6);

The A12 hydraulic fluid port of described the 4th solenoid-operated proportional reversal valve (12) is by the inside oil duct of hydraulic control unit (6) and the B11 hydraulic fluid port of the 3rd solenoid-operated proportional reversal valve (11), the P8 oil-in of the 3rd safety valve (8), the T7 oil-out of the 3rd one way valve (7), the 6c hydraulic fluid port of hydraulic control unit (6) is communicated with, the B12 hydraulic fluid port of the 4th solenoid-operated proportional reversal valve (12) is by the inside oil duct of hydraulic control unit (6) and the A11 hydraulic fluid port of the 3rd solenoid-operated proportional reversal valve (11), the P10 hydraulic fluid port of the second safety valve (10), the T9 oil-out of the second one way valve (9), the 6d hydraulic fluid port of hydraulic control unit (6) is interconnected,

The 6a hydraulic fluid port of described hydraulic control unit (6) is communicated with the oil-out of hydraulic pump (23) by fluid pressure line, the 6b hydraulic fluid port of hydraulic control unit (6) is communicated with the oil return opening of low pressure sealed reservoir (21) by fluid pressure line, the 6c hydraulic fluid port of hydraulic control unit (6) is communicated with the loculus of rotary ink tank (20) by fluid pressure line, the 6d hydraulic fluid port of hydraulic control unit (6) is communicated with the large chamber of rotary ink tank (20) by fluid pressure line, the 6e hydraulic fluid port of hydraulic control unit (6) is communicated with the signal detecting mouth of second pressure sensor (19), the 6f hydraulic fluid port of hydraulic control unit (6) is communicated with intermediate-pressure accumulator (18), the 6g hydraulic fluid port of hydraulic control unit (6) is communicated with the signal detecting mouth of first pressure sensor (17), the 6h hydraulic fluid port of hydraulic control unit (6) is communicated with high pressure accumulator (16) by fluid pressure line, the 6i hydraulic fluid port of hydraulic control unit (6) is communicated with the loculus of boom cylinder (15) by fluid pressure line, the 6j hydraulic fluid port of hydraulic control unit (6) is communicated with the large chamber of boom cylinder (15) by fluid pressure line.

2. loader hydraulic system as claimed in claim 1, is characterized in that: described high pressure accumulator (16) is piston type or bladder accumulator.

3. loader hydraulic system as claimed in claim 1, is characterized in that: described intermediate-pressure accumulator (18) is piston type or bladder accumulator.

4. loader hydraulic system as claimed in claim 1, is characterized in that: described low pressure sealed reservoir (21) is enclosed gas charging fuel tank.

5. loader hydraulic system as claimed in claim 1, is characterized in that: described the first solenoid operated directional valve (1) is bi-bit bi-pass solenoid operated directional valve.

6. loader hydraulic system as claimed in claim 1, is characterized in that: described the second solenoid operated directional valve (3) is bi-bit bi-pass solenoid operated directional valve.

7. loader hydraulic system as claimed in claim 1, is characterized in that: described the 3rd solenoid operated directional valve (13) is bi-bit bi-pass solenoid operated directional valve.

8. loader hydraulic system as claimed in claim 1, is characterized in that: described the first solenoid-operated proportional reversal valve (4) is two-position four-way solenoid-operated proportional reversal valve.

9. loader hydraulic system as claimed in claim 1, is characterized in that: described the second solenoid-operated proportional reversal valve (5) is two-position four-way solenoid-operated proportional reversal valve.

10. loader hydraulic system as claimed in claim 1, is characterized in that: described the 3rd solenoid-operated proportional reversal valve (11) is two-position four-way solenoid-operated proportional reversal valve.

11. loader hydraulic systems as claimed in claim 1, is characterized in that: described the 4th solenoid-operated proportional reversal valve (12) is two-position four-way solenoid-operated proportional reversal valve.

12. loader hydraulic systems as claimed in claim 1, is characterized in that: the operating pressure of described high pressure accumulator (16) is 16～35MPa.

13. loader hydraulic systems as claimed in claim 1, is characterized in that: the operating pressure of described intermediate-pressure accumulator (18) is 4～15MPa.

14. loader hydraulic systems as claimed in claim 1, is characterized in that: the operating pressure of described low pressure sealed reservoir (21) is 0.5～3 MPa.

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