Standby hydraulic system of excavator and control method of standby hydraulic system

Abstract

The invention provides an excavator standby hydraulic system and a control method thereof, and belongs to the technical field of engineering machinery, the excavator standby hydraulic system comprises a standby hydraulic system, the standby hydraulic system is connected with a hydraulic oil tank and a main valve, the standby hydraulic system comprises a standby pump, and an outlet of the standby pump is connected with an inlet of a diverter valve; a first outlet of the diverter valve is connected with a first inlet of the main valve, and a second outlet of the diverter valve is connected with a first inlet of the shuttle valve. By arranging the standby hydraulic system, normal action of the excavator can be guaranteed when the main hydraulic system breaks down, and the situation that the engineering progress is affected due to the fact that the excavator cannot move is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering machinery, and in particular relates to a backup hydraulic system for an excavator and a control method thereof. Background Art

[0002] Most of the existing excavators are hydraulic excavators, which are driven by an electric motor or engine to drive a hydraulic pump, which drives hydraulic actuators such as hydraulic cylinders and hydraulic motors to drive the excavator to travel, rotate the upper mechanism, and move the boom, dipper and bucket.

[0003] Traditional excavators usually only have a main hydraulic system, i.e., a working hydraulic system. When the excavator is operating, if the engine or hydraulic system fails, it often causes a shutdown. Once a shutdown failure occurs, the excavator cannot move, occupying the construction station and affecting the progress of the project. At the same time, because the excavator cannot move, it can only be repaired on site, resulting in a waste of manpower and material resources. In addition, the construction site environment is harsh, and on-site repairs are likely to contaminate the hydraulic system, increasing the probability of hydraulic system failure. Summary of the invention

[0004] In view of the defects or shortcomings in the prior art, the present invention provides a backup hydraulic system for an excavator and a control method thereof. By setting up a backup hydraulic system, the normal operation of the excavator can be guaranteed when a main hydraulic system fails, thereby avoiding the inability of the excavator to move and affecting the progress of the project.

[0005] To achieve the above object, the present invention adopts the following technical solution: In the first aspect, an embodiment of the present invention provides a backup hydraulic system for an excavator, including a backup hydraulic system, which is connected to a hydraulic oil tank and a main valve. The backup hydraulic system includes a backup pump, wherein the outlet of the backup pump is connected to the inlet of a diverter valve, the first outlet of the diverter valve is connected to the first inlet of the main valve, the second outlet of the diverter valve is connected to the first inlet of a shuttle valve, and the outlet of the shuttle valve is connected to the second inlet of the main valve.

[0006] Furthermore, it also includes a main hydraulic system, which is connected to the hydraulic cylinder and the main valve.

[0007] Furthermore, the main hydraulic system comprises a main pump, an inlet of the main pump is connected to the hydraulic oil tank via an oil pipe, and an outlet of the main pump is connected to the first inlet of the main valve via an oil pipe.

[0008] Furthermore, the main hydraulic system also includes a pilot pump, the inlet of the pilot pump is connected to the hydraulic oil tank through an oil pipe, and the outlet of the pilot pump is connected to the second inlet of the shuttle valve through the oil pipe.

[0009] Furthermore, the outlet of the shuttle valve is also connected to the main pump.

[0010] Furthermore, the backup hydraulic system also includes a backup engine, and the output shaft of the backup engine is connected to the input shaft of the backup pump.

[0011] Furthermore, a pilot throttle valve and a pilot overflow valve are arranged in the diverter valve, wherein the pilot throttle valve is arranged at the inlet of the diverter valve, and the pilot overflow valve is arranged between the pilot throttle valve and the second outlet of the diverter valve.

[0012] Furthermore, a first one-way valve is provided on the pipeline connecting the first outlet of the diverter valve and the main valve, and a second one-way valve is provided on the pipeline between the main pump and the main valve.

[0013] Furthermore, the main valve and the hydraulic oil tank are connected via an oil return pipe.

[0014] In a second aspect, an embodiment of the present invention provides a control method for an excavator backup hydraulic system, using the excavator backup hydraulic system as described above, comprising the following steps: When the main hydraulic system is working normally and the standby engine is not working, the hydraulic oil in the hydraulic oil tank is converted into high-pressure hydraulic oil by the main pump, providing a high-pressure oil source for the main valve. At this time, the second inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the hydraulic oil in the hydraulic oil tank is converted into low-pressure hydraulic oil by the pilot pump. The low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve, providing a low-pressure oil source for the main valve and the main pump; When the main hydraulic system cannot work normally, the standby engine starts to drive the standby pump to rotate. The diverter valve diverts the hydraulic oil output by the standby pump into high-pressure hydraulic oil and low-pressure hydraulic oil. The high-pressure hydraulic oil enters the main valve to provide a high-pressure oil source for the main valve. At this time, the first inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve to provide a low-pressure oil source for the main valve and the main pump.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention sets up a backup hydraulic system. When the main hydraulic system fails to work normally, the backup hydraulic system provides high-pressure oil source and low-pressure oil source for the main valve to ensure the normal operation of the excavator and avoid affecting the progress of the project due to the inability of the excavator to move.

[0016] 2. The present invention can divide a small part of the hydraulic oil from the standby oil circuit to the pilot oil circuit by setting a pilot throttle valve. At the same time, a pilot pressure relief valve is set in the diverter valve to ensure the low-pressure demand of the pilot system, so that the standby hydraulic system does not need to be equipped with a pilot pump, thereby simplifying the structure of the standby hydraulic system while ensuring normal operation.

[0017] 3. The present invention provides a shuttle valve to connect the main pilot oil circuit and the spare pilot oil circuit through the shuttle valve. When the main hydraulic system fails, the spare pilot oil circuit can be connected in time through the shuttle valve to control the operation of the entire vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of a hydraulic system in Embodiment 1 of the present invention; Among them, 1. hydraulic oil tank; 2. main valve; 3. main pump; 4. pilot pump; 5. shuttle valve; 6. spare pump; 7. spare engine; 8. diverter valve; 9. first one-way valve; 10. second one-way valve. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0020] The high-pressure hydraulic oil mentioned in the present invention is used in the high-pressure environment of the excavator, such as various working cylinders on the excavator, to drive the excavator to move, and the low-pressure hydraulic oil is used in the low-pressure environment of the excavator, such as various control valves on the excavator to control the movement of the excavator.

[0021] Embodiment 1 A typical implementation of the present invention is as follows Figure 1 As shown, an excavator backup hydraulic system includes a main hydraulic system and a backup hydraulic system. Both the main hydraulic system and the backup hydraulic system are connected to a hydraulic oil tank 1, and hydraulic oil is provided to the main hydraulic system and the backup hydraulic system through the hydraulic oil tank 1. The main hydraulic system and the backup hydraulic system are also connected to a main valve 2. The main hydraulic system and the backup hydraulic system deliver hydraulic oil of set pressure to the main valve 2, and the main valve 2 controls the flow direction and flow of the hydraulic oil, thereby realizing the control of various operations and actions of the excavator.

[0022] The main valve 2 is connected to the hydraulic oil tank 1 through an oil return pipe, thereby realizing the circulation of hydraulic oil in the entire hydraulic system.

[0023] Under normal circumstances, the backup hydraulic system does not work, and the main hydraulic system provides hydraulic oil with a set pressure to the main valve 2, thereby controlling the normal operation of the excavator. When the main hydraulic system fails and cannot work, the backup hydraulic system is started, and the backup hydraulic system provides hydraulic oil with a set pressure to the main valve 2 to ensure the normal operation of the excavator.

[0024] The main hydraulic system includes a main circuit and a main pilot circuit, wherein the main circuit can generate a high-pressure oil source, which is transported to the working cylinders and travel cylinders located in various parts of the excavator through the main valve 2, thereby realizing various actions of the excavator, and the pilot circuit can generate a low-pressure oil source, which is transported to the control valves located in various parts of the excavator through the main valve 2, thereby controlling various actions of the excavator.

[0025] The main circuit includes a main pump 3, the inlet of the main pump 3 is connected to the hydraulic oil tank 1 through an oil pipe, and the outlet of the main pump 3 is connected to the first inlet of the main valve 2 through an oil pipe. The hydraulic oil in the hydraulic oil tank 1 is converted into high-pressure hydraulic oil by the main pump 3, thereby providing a high-pressure oil source for the main valve 2.

[0026] The pilot oil circuit includes a pilot pump 4, the inlet of the pilot pump 4 is connected to the hydraulic oil tank 1 through an oil pipe, the outlet of the pilot pump 4 is connected to the second inlet of the shuttle valve 5 through an oil pipe, and the outlet of the shuttle valve 5 is connected to the second inlet of the main valve 2 and the main pump 3 through an oil pipe. The hydraulic oil in the hydraulic oil tank 1 is converted into low-pressure hydraulic oil through the pilot pump 4, thereby providing a low-pressure oil source for the main valve 2 and the main pump 3.

[0027] When the main hydraulic system fails, the backup hydraulic system is started to provide high-pressure oil source and low-pressure oil source to ensure the normal operation of the excavator.

[0028] The backup hydraulic system includes a backup pump 6 and a backup engine 7. The output shaft of the backup engine 7 is connected to the input shaft of the backup pump 6. The backup pump 6 is driven to rotate by the backup engine 7. When the main hydraulic system fails, the backup engine 7 is started and the backup pump 6 is driven to run by the backup engine 7, thereby starting the backup hydraulic system.

[0029] The inlet of the standby pump 6 is connected to the hydraulic oil tank 1 through an oil pipe, and oil is supplied to the standby pump 6 through the hydraulic oil tank 1. The outlet of the standby pump 6 is connected to the inlet of the diverter valve 8 through an oil pipe. The diverter valve 8 diverts the standby oil circuit into a standby main oil circuit and a standby pilot oil circuit. The standby main oil circuit replaces the main oil circuit to provide a high-pressure oil source, and the standby pilot oil circuit replaces the pilot oil circuit to provide a low-pressure oil source, thereby ensuring the normal operation of the excavator.

[0030] Specifically, a pilot throttle valve and a pilot overflow valve are provided in the diverter valve 8, wherein the pilot throttle valve is provided at the inlet of the diverter valve 8, and the pilot overflow valve is provided between the pilot throttle valve and the second outlet of the diverter valve 8. The pilot throttle valve can separate a part of the hydraulic oil from the high-pressure hydraulic oil generated by the standby pump 6 as a standby pilot oil circuit, and the pilot overflow valve converts the separated hydraulic oil from high-pressure hydraulic oil into low-pressure hydraulic oil, thereby ensuring the low-pressure requirement of the standby pilot oil circuit.

[0031] By setting a pilot throttle valve, a small part of the hydraulic oil in the standby oil circuit can be diverted to the pilot oil circuit. At the same time, a pilot pressure relief valve is set in the diverter valve 8 to ensure the low-pressure requirement of the pilot system, so that the standby hydraulic system does not need to be equipped with a pilot pump, thereby simplifying the structure of the standby hydraulic system while ensuring normal operation.

[0032] High-pressure hydraulic oil flows out from the first outlet of the diverter valve 8 to form a backup main oil circuit. The first outlet of the diverter valve 8 is connected to the first inlet of the main valve 2 through an oil pipe. When the main hydraulic system fails, a high-pressure oil source is provided to the main valve 2.

[0033] The low-pressure hydraulic oil flows out from the second outlet of the diverter valve 8 to form a backup pilot oil circuit. The second outlet of the diverter valve 8 is connected to the first inlet of the shuttle valve 5 through an oil pipe. When the main hydraulic system fails, a low-pressure oil source is provided for the main valve 2 and the main pump 3.

[0034] The first inlet of the shuttle valve 5 is connected to the second outlet of the diverter valve 8, and the second inlet of the shuttle valve 5 is connected to the outlet of the pilot pump 4. The shuttle valve 5 is used to select the main pilot oil circuit and the backup pilot oil circuit. When the main hydraulic system is working and the backup hydraulic system is not working, the second inlet of the shuttle valve 5 is connected to the outlet of the shuttle valve 5. At this time, the main pilot oil circuit is selected to provide a low-pressure oil source to control the operation of the entire vehicle. When the main hydraulic system is not working and the backup hydraulic system is working, the first inlet of the shuttle valve 5 is connected to the outlet of the shuttle valve 5. At this time, the backup pilot oil circuit is selected to provide a low-pressure oil source to control the operation of the entire vehicle.

[0035] A first one-way valve 9 is arranged on the pipeline connecting the first outlet of the diverter valve 8 and the main valve 2, and a second one-way valve 10 is arranged on the pipeline between the main pump 3 and the main valve 2. By arranging the first one-way valve 9 and the second one-way valve 10, the hydraulic oil of the main pump 3 and the backup pump 6 can only flow into the main valve 2 in one direction, thereby preventing the backflow of high-pressure hydraulic oil from causing malfunction of the main pump 3 or the backup pump 6.

[0036] Embodiment 2 This embodiment provides a control method for an excavator backup hydraulic system, using an excavator backup hydraulic system as described in the first embodiment, including the following steps: When the main hydraulic system is working normally and the standby engine is not working, the hydraulic oil in the hydraulic oil tank is converted into high-pressure hydraulic oil by the main pump, providing a high-pressure oil source for the main valve. At this time, the second inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the hydraulic oil in the hydraulic oil tank is converted into low-pressure hydraulic oil by the pilot pump. The low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve, providing a low-pressure oil source for the main valve and the main pump; When the main hydraulic system cannot work normally, the standby engine starts to drive the standby pump to rotate. The diverter valve diverts the hydraulic oil output by the standby pump into high-pressure hydraulic oil and low-pressure hydraulic oil. The high-pressure hydraulic oil enters the main valve to provide a high-pressure oil source for the main valve. At this time, the first inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve to provide a low-pressure oil source for the main valve and the main pump.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An excavator backup hydraulic system, characterized in that: The invention comprises a backup hydraulic system, which is connected to a hydraulic oil tank and a main valve. The backup hydraulic system comprises a backup pump, the outlet of the backup pump is connected to the inlet of a diverter valve, the first outlet of the diverter valve is connected to the first inlet of the main valve, the second outlet of the diverter valve is connected to the first inlet of a shuttle valve, and the outlet of the shuttle valve is connected to the second inlet of the main valve.

2. The backup hydraulic system for an excavator according to claim 1, characterized in that: It also includes a main hydraulic system, which is connected to the hydraulic cylinder and the main valve.

3. The backup hydraulic system for an excavator as claimed in claim 2, characterized in that: The main hydraulic system comprises a main pump, the inlet of the main pump is connected to the hydraulic oil tank through an oil pipe, and the outlet of the main pump is connected to the first inlet of the main valve through an oil pipe.

4. The backup hydraulic system for an excavator as claimed in claim 3, characterized in that: The main hydraulic system also includes a pilot pump, the inlet of the pilot pump is connected to the hydraulic oil tank through an oil pipe, and the outlet of the pilot pump is connected to the second inlet of the shuttle valve through the oil pipe.

5. The backup hydraulic system for an excavator as claimed in claim 4, characterized in that: The outlet of the shuttle valve is also connected to the main pump.

6. The backup hydraulic system for an excavator according to claim 1, characterized in that: The backup hydraulic system further comprises a backup engine, wherein an output shaft of the backup engine is connected to an input shaft of the backup pump.

7. The backup hydraulic system for an excavator according to claim 1, characterized in that: A pilot throttle valve and a pilot overflow valve are arranged in the diverter valve, wherein the pilot throttle valve is arranged at the inlet of the diverter valve, and the pilot overflow valve is arranged between the pilot throttle valve and the second outlet of the diverter valve.

8. The backup hydraulic system for an excavator as claimed in claim 3, characterized in that: A first one-way valve is arranged on the pipeline connecting the first outlet of the diverter valve and the main valve, and a second one-way valve is arranged on the pipeline between the main pump and the main valve.

9. The backup hydraulic system for an excavator according to claim 1, characterized in that: The main valve and the hydraulic oil tank are connected through an oil return pipe.

10. The control method of the backup hydraulic system of an excavator according to claim 1, characterized in that: The following steps are involved: When the main hydraulic system is working normally and the standby engine is not working, the hydraulic oil in the hydraulic oil tank is converted into high-pressure hydraulic oil by the main pump, providing a high-pressure oil source for the main valve. At this time, the second inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the hydraulic oil in the hydraulic oil tank is converted into low-pressure hydraulic oil by the pilot pump. The low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve, providing a low-pressure oil source for the main valve and the main pump; When the main hydraulic system cannot work normally, the standby engine starts to drive the standby pump to rotate. The diverter valve diverts the hydraulic oil output by the standby pump into high-pressure hydraulic oil and low-pressure hydraulic oil. The high-pressure hydraulic oil enters the main valve to provide a high-pressure oil source for the main valve. At this time, the first inlet of the shuttle valve is connected to the outlet of the shuttle valve, and the low-pressure hydraulic oil enters the main valve and the main pump through the shuttle valve to provide a low-pressure oil source for the main valve and the main pump.

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