Hydraulic system and engineering machinery thereof

Abstract

The utility model discloses a hydraulic system and engineering machinery thereof, and belongs to the technical field of engineering machinery. The defect that in the prior art, two pumps need to be additionally arranged in a traditional lifting system, and consequently cost is high is overcome. The main body structure of the device comprises a pilot oil source valve, a working pump, a first pump, a second pump, a working system, a lifting system, a heat dissipation system and a machine tool rotation system, an oil outlet of the working pump is respectively connected with the pilot oil source valve and the working system, an oil outlet of the first pump is respectively connected with the lifting system and the heat dissipation system, and an oil outlet of the second pump is connected with the machine tool rotation system. The utility model is mainly applied to engineering machinery such as excavators and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of construction machinery, and particularly relates to a hydraulic system and a construction machinery thereof. Background Art

[0002] At present, there are more and more types of differentiated excavator products, and customers have more and more requirements for functions. In order to meet the operation with high vision, for example, the cab needs to have a lifting function, and at the same time the tool needs to have a slewing function, which can be used for a shell bucket, etc.; in order to meet the lifting of the cab and the slewing of the tool, generally two additional pump oil sources are required to meet the demand. Since two additional pumps are added, the main pump system of the excavator needs to be changed. By adding a power take-off port on the pump or adding a power take-off port on the engine, the space requirement for the pump chamber is very large, and the appearance parts need to be adjusted to add 2 additional pumps, so the cost is relatively high. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a hydraulic system and a construction machinery thereof.

[0004] In order to achieve the above purpose, the utility model is realized by adopting the following technical solutions:

[0005] A hydraulic system includes a pilot oil source valve, a working pump, pump one, pump two, a working system, a lifting system, a heat dissipation system and a tool slewing system. The oil outlet of the working pump is respectively connected with the pilot oil source valve and the working system. The oil outlet of pump one is respectively connected with the lifting system and the heat dissipation system. The oil outlet of pump two is connected with the tool slewing system.

[0006] Preferably, the lifting system includes a directional control valve connected to the oil outlet of pump one, a manual lowering valve and a lifting oil cylinder connected to the directional control valve. The oil inlet of the manual lowering valve is connected with the large chamber of the lifting oil cylinder. The oil outlet of the manual lowering valve is respectively connected with the small chamber of the lifting oil cylinder and the hydraulic oil tank.

[0007] Preferably, a balance valve is arranged between the directional control valve and the lifting oil cylinder.

[0008] Preferably, the manual lowering valve includes a check valve, a throttle valve and a switch valve. The oil inlet of the switch valve is connected with the large chamber of the lifting oil cylinder. The oil outlet of the switch valve is respectively connected with the oil inlet of the check valve and the oil inlet of the throttle valve. The oil outlet of the check valve is connected with the small chamber of the lifting oil cylinder. The oil outlet of the throttle valve is connected with the hydraulic oil tank.

[0009] Preferably, the heat dissipation system includes a throttle directional control valve and a heat dissipation motor assembly. The oil inlet of the throttle directional control valve is connected with the oil outlet of pump one. The oil outlet of the throttle directional control valve is connected with the heat dissipation motor assembly.

[0010] Preferably, the implement slewing system includes a reversing valve assembly and a slewing motor. The oil inlet of the reversing valve assembly is connected to the oil outlet of Pump II, and the oil outlet of the reversing valve assembly is connected to the slewing motor through a two-way overflow valve.

[0011] Preferably, the working system includes a main valve connected to the oil outlet of the working pump and a negative flow valve connected to the main valve.

[0012] Preferably, the working pump is a double pump.

[0013] A construction machinery is provided with a hydraulic system as described in any one of the above.

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0015] 1. When in the initial position, the large chamber and the small chamber of the lifting cylinder are not connected. When the solenoid valve a4 of the manual lowering valve is energized, pressure is generated in the large chamber of the lifting cylinder under the action of the gravity of the cab. Part of the pressure is introduced into the small chamber of the lifting cylinder through a check valve, and part of the pressure is connected to the hydraulic oil tank through a throttle valve. During the falling process, oil can be replenished to the small chamber of the lifting cylinder to prevent the small chamber of the lifting cylinder from sucking air. At the same time, the excess oil is slowly released through the throttle orifice of the throttle valve to achieve the slow descent function. By adjusting the size of the throttle orifice, the time and comfort of the emergency descent can be adjusted;

[0016] 2. Through the throttle reversing valve, Pump I can be used for the cooling motor assembly when the throttle reversing valve is not working. When the throttle reversing valve works, the oil can be used for the lifting of the cab and at the same time keep the fan running at a certain speed, saving one pump;

[0017] 3. The oil source is led out from the working pump, and the throttling pressure of the negative flow valve is used as the oil source of the pilot oil source valve. When the pressure of the working pump is high, the pressure reducing and energy storage function of the pilot oil source valve is utilized, saving one pump source;

[0018] 4. The present utility model saves two pumps compared with the prior art, making the layout of the pump chamber system convenient and enabling rapid implementation of system changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the hydraulic system diagram of the present utility model;

[0020] Figure 2 is the connection schematic diagram of the manual lowering valve in the present utility model.

[0021] In the figure: 1. Pilot oil source valve; 2. Working pump; 3. Main valve; 4. Negative flow valve; 5. Relief valve; 6. Pump 1; 7. Pump 2; 8. Throttle reversing valve; 9. Cooling motor assembly; 10. Reversing valve assembly; 11. Swing motor; 12. Two-way relief valve; 13. Reversing valve; 14. Balance valve; 15. Manual lowering valve; 16. Lifting cylinder; 17. Pilot oil source; 18. Pump 3; 19. Pump 4; 20. Check valve; 21. Throttle valve; 22. Switch valve. Specific embodiments

[0022] The present utility model will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0023] Embodiment 1:

[0024] As Figure 1 shown, a hydraulic system includes a pilot oil source valve 1, a working pump 2, a pump 1 6, a pump 2 7, a working system, a lifting system, a cooling system, and a tool swing system. The oil outlet of the working pump 2 is respectively connected to the pilot oil source valve 1 and the working system. The oil outlet of the pump 1 6 is respectively connected to the lifting system and the cooling system. The oil outlet of the pump 2 7 is connected to the tool swing system. Among them, the working pump 2 is a double pump.

[0025] Under the premise of not changing the existing pump hydraulic system, this embodiment realizes that the whole machine obtains an additional oil source, can realize the lifting of the cab and the swing function of the front tool, and at the same time is equipped with an emergency lowering function to meet the emergency lowering function when the oil source fails; at the same time, the oil source (i.e., the pilot oil source valve 1) is led out from the main pump port of the negative flow hydraulic system and used as the pilot oil source. Since there is only throttling pressure when the working pump 2 is in the non-working state, it can meet the driving pressure of the pilot. When the main valve 3 starts to work, the pump port pressure is very high. Since the pilot pressure is relatively low, the pressure reducing valve and accumulator in the pilot oil source valve 1 are used for energy storage and used as the pilot pump.

[0026] Embodiment 2:

[0027] A hydraulic system, different from Embodiment 1, is that the lifting system includes a reversing valve 13 connected to the oil outlet of the pump 1 6, a manual lowering valve 15, and a lifting cylinder 16 connected to the reversing valve 13. The oil inlet of the manual lowering valve 15 is connected to the large chamber of the lifting cylinder 16. The oil outlet of the manual lowering valve 15 is respectively connected to the small chamber of the lifting cylinder 16 and the hydraulic oil tank. A balance valve 14 is provided between the reversing valve 13 and the lifting cylinder 16. When the cab is lifted, the hydraulic system does not work. By utilizing the characteristic that the cooling pump and the lifting cab do not work at the same time, the cooling pump (the pump 1 6 is the cooling pump) is used to control the lifting of the cab through a reversing valve 13 to solve the oil source problem and serve as the lifting oil source of the whole machine.

[0028] As Figure 2As shown in the figure, the manual lowering valve 15 includes a check valve 20, a throttle valve 21, and a switching valve 22. The oil inlet of the switching valve 22 is connected to the large chamber of the lifting cylinder 16. The oil outlet of the switching valve 22 is respectively connected to the oil inlet of the check valve 20 and the oil inlet of the throttle valve 21. The oil outlet of the check valve 20 is connected to the small chamber of the lifting cylinder 16. The oil outlet of the throttle valve 21 is connected to the hydraulic oil tank. By means of the manual lowering valve 15, while the large chamber can be lowered, it is ensured that the small chamber does not suck air, and at the same time, the emergency lowering speed can be adjusted by the throttle valve 21.

[0029] Further, the heat dissipation system includes a throttle reversing valve 8 and a heat dissipation motor assembly 9. The oil inlet of the throttle reversing valve 8 is connected to the oil outlet of the first pump 6. The oil outlet of the throttle reversing valve 8 is connected to the heat dissipation motor assembly 9.

[0030] Further, the machine tool slewing system includes a reversing valve assembly 10 and a slewing motor 11. The oil inlet of the reversing valve assembly 10 is connected to the oil outlet of the second pump 7. The oil outlet of the reversing valve assembly 10 is connected to the slewing motor 11 through a two-way overflow valve 12.

[0031] Further, the working system includes a main valve 3 connected to the oil outlet of the working pump 2 and a negative flow valve 4 connected to the main valve 3.

[0032] Embodiment 3:

[0033] A construction machinery is provided with a hydraulic system as described in Embodiment 1 or Embodiment 2.

[0034] The working principle of the present utility model is as follows:

[0035] Without adding a pump, two oil sources can be achieved: the first oil source is the cab lifting oil source. Utilizing the characteristics that when the cab is lifted, the working device system does not work and the heat dissipation system can work at a low speed or not work, the heat dissipation pump (the first pump 6 is the heat dissipation pump) is used as the lifting oil source. When one of the a2 end and the b2 end of the reversing valve 13 is energized, the a1 end of the throttle reversing valve 8 is also energized simultaneously; when the reversing valve 13 does not work, the oil fluid passes through the throttle reversing valve 8 to reach the heat dissipation motor assembly 9. When the solenoid valve a2 or b2 of the reversing valve 13 is energized, the a1 end of the throttle reversing valve 8 starts to work, and the throttle reversing valve 8 starts to function, ensuring that the first pump 6 can build pressure. A part of the oil fluid is used for lifting, and a part reaches the heat dissipation motor assembly 9. At the same time, a balance valve 14 is arranged on the lifting cylinder 16 to ensure the smooth lifting and lowering of the cylinder.

[0036] The pilot pump in the prior art (i.e., the second pump 7 is connected to the pilot oil source 17) is changed to the second pump 7 to provide oil source for the slewing of the slewing motor 11. The maximum pressure during operation is controlled by the overflow valve 5. The reversing valve assembly 10 controls the left and right slewing of the slewing motor 11, and the two-way overflow valve 12 controls the overload overflow of the slewing motor 11.

[0037] At this time, the system lacks a pilot oil source. When the main valve 3 is not working, the working pump 2 has a minimum displacement to provide a negative flow signal for the system. The negative flow valve 4 has a throttling effect, which can ensure that the oil drawn from the working pump 2 to the pilot oil source valve 1 has a certain working pressure and can be used as the pilot pressure. The pressure oil is filled into the pilot oil source valve 1 and can drive the main valve 3 to work. When the main valve 3 is working, the high-pressure oil in the system passes through the pilot oil source valve 1 for pressure reduction and energy storage for pilot use, solving the problem of the pilot pump.

[0038] The working principle during emergency descent is as follows:

[0039] In this embodiment, the manual descent valve 15 is the emergency descent valve. When the oil source of the lifting cylinder 16, such as pump one 6, fails, the manual descent valve 15 can be operated to descend. The emergency descent function does not require an additional oil source. The specific working principle is as follows: When the manual descent valve 15 is not operated, the solenoid valve a4 is de-energized, and the large chamber and the small chamber of the lifting cylinder 16 are in an isolated state, and the emergency descent function does not work; when the manual descent valve 15 is pressed, the solenoid valve a4 is energized, causing the large chamber of the lifting cylinder 16 to generate pressure under the action of the gravity of the cab. Part of the oil is introduced into the small chamber of the lifting cylinder 16 through the one-way valve 20, which can supplement the oil in the small chamber of the lifting cylinder 16 during the falling process to prevent the small chamber of the lifting cylinder 16 from sucking air. Part of the oil is connected to the hydraulic oil tank through the throttle valve 21, and the oil returns to the tank to achieve emergency descent. The excess oil is slowly released through the throttle orifice of the throttle valve 21 to achieve the slow descent function. At the same time, by adjusting the size of the throttle orifice, the time and comfort of the emergency descent can be adjusted.

Claims

1. A hydraulic system, characterized in that: The invention comprises a pilot oil source valve (1), a working pump (2), a pump 1 (6), a pump 2 (7), a working system, a lifting system, a heat dissipation system and a machine tool rotation system, wherein the oil outlet of the working pump (2) is respectively connected to the pilot oil source valve (1) and the working system, the oil outlet of the pump 1 (6) is respectively connected to the lifting system and the heat dissipation system, and the oil outlet of the pump 2 (7) is connected to the machine tool rotation system.

2. The hydraulic system according to claim 1, characterized in that: The lifting system comprises a reversing valve (13) connected to the oil outlet of pump 1 (6), a manual descending valve (15) and a lifting cylinder (16) connected to the reversing valve (13); the oil inlet of the manual descending valve (15) is connected to the large chamber of the lifting cylinder (16); and the oil outlet of the manual descending valve (15) is respectively connected to the small chamber of the lifting cylinder (16) and the hydraulic oil tank.

3. The hydraulic system according to claim 2, characterized in that: A balance valve (14) is provided between the reversing valve (13) and the lifting cylinder (16).

4. The hydraulic system according to claim 2, characterized in that: The manual descending valve (15) comprises a one-way valve (20), a throttle valve (21) and a switch valve (22); the oil inlet of the switch valve (22) is connected to the large chamber of the lifting cylinder (16); the oil outlet of the switch valve (22) is respectively connected to the oil inlet of the one-way valve (20) and the oil inlet of the throttle valve (21); the oil outlet of the one-way valve (20) is connected to the small chamber of the lifting cylinder (16); and the oil outlet of the throttle valve (21) is connected to the hydraulic oil tank.

5. The hydraulic system according to any one of claims 1 to 4, characterized in that: The heat dissipation system comprises a throttling reversing valve (8) and a heat dissipation motor assembly (9), wherein the oil inlet of the throttling reversing valve (8) is connected to the oil outlet of the pump 1 (6), and the oil outlet of the throttling reversing valve (8) is connected to the heat dissipation motor assembly (9).

6. The hydraulic system according to any one of claims 1 to 4, characterized in that: The tool rotary system comprises a reversing valve assembly (10) and a rotary motor (11); the oil inlet of the reversing valve assembly (10) is connected to the oil outlet of the second pump (7); and the oil outlet of the reversing valve assembly (10) is connected to the rotary motor (11) via a two-way overflow valve (12).

7. The hydraulic system according to any one of claims 1 to 4, characterized in that: The working system comprises a main valve (3) connected to the oil outlet of the working pump (2) and a negative flow valve (4) connected to the main valve (3).

8. The hydraulic system according to any one of claims 1 to 4, characterized in that: The working pump (2) is a double pump.

9. An engineering machine, characterized in that: The engineering machinery is provided with a hydraulic system as described in any one of claims 1 to 4.

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