Telescopic control system of crane

Abstract

The utility model discloses a telescopic control system of a crane, which comprises an oil cylinder provided with a first oil cavity and a second oil cavity, the first oil cavity is connected with a first oil way, and the second oil cavity is connected with a second oil way; the oil tank is selectively connected with the first oil way or the second oil way through the reversing valve. The balance valve is arranged on the first oil way, oil from the oil tank to the first oil cavity can freely pass through the balance valve, the oil from the first oil cavity to the oil tank is controlled by pressure of a pilot port of the balance valve to flow, and the pilot port is connected with the second oil way through a third oil way. The third oil way is provided with a first proportional directional valve and a second proportional directional valve, and the first proportional directional valve and the second proportional directional valve are further connected with the oil tank through a fourth oil way. The telescopic control system of the crane further comprises a damper, the damper is connected with the third oil way and the fourth oil way through a fifth oil way, and the joint of the fifth oil way and the third oil way is closer to the pilot port than the first proportional reversing valve. The telescopic safety can be improved.

Description

Technical Field

[0001] The utility model belongs to a hydraulic system in the technical field of lifting equipment, in particular to a crane telescopic control system. Background Art

[0002] After the development in recent years, infrastructure construction has been moving towards high efficiency. The market has higher and higher requirements for crane lifting performance, work efficiency and safety. How to quickly and safely improve lifting efficiency has become the key to crane design.

[0003] At present, large-tonnage cranes generally use single-cylinder latches to control the extension and retraction of the main arm. The extension and retraction of the arm must be carried out in a specific order. At present, the main arm of the crane is generally extended without considering the load. This requires that the main arm must be extended to the selected working position in a specific order before the lifting task is carried out. In addition, during the lifting of heavy objects, the length of the main arm is not allowed to be changed. If you want to change the length of the main arm, you need to put the heavy object down and then extend and retract the main arm, which will cause extra time waste and affect the efficiency of the lifting. There are special requirements for the lifting of special objects, that is, the heavy object is not allowed to fall to the ground after leaving the ground. If you want to change the arm length, the main arm must be able to be extended and retracted with load.

[0004] The existing crane telescopic control system is roughly as follows Figure 1 As shown, the large cavity of the telescopic cylinder is connected to a balancing valve, the P port is connected to the A port, the cylinder extends outward, the P port is connected to the B port, the pressure oil directly acts on the balancing valve pilot port, the balancing valve is switched, the oil in the large cavity of the cylinder returns to the oil tank through the balancing valve, the cylinder retracts, and the extension and retraction of the telescopic cylinder are controlled by the reversing valve.

[0005] This system has the following main disadvantages:

[0006] The pilot port of the balancing valve is directly connected to the working oil port, the solenoid reversing valve is stuck, the P port and the B port are connected, and there will be a certain pressure in the oil port. The pressure acts on the pilot oil port of the balancing valve, causing the balancing valve to open, causing the telescopic cylinder to retract, especially when retracted with load. The main arm is in a state without the arm pin inserted, and the telescopic cylinder is in a suspended state with load. The back pressure causes the balancing valve to fail to close in time, which will bring certain hidden dangers.

[0007] When the oil cylinder retracts, the balance valve always remains in the maximum opening state and cannot effectively control the retraction speed of the main arm.

[0008] After searching, some existing design schemes, such as CN114412855A, control the opening of the telescopic balancing valve by grouping the telescopic balancing valve group and utilizing the external control oil circuit, thereby achieving the purpose of accurately controlling the retraction speed of the boom. This structural design is relatively complicated and cannot effectively solve the problem that the balancing valve cannot be closed in time due to back pressure. Summary of the invention

[0009] In order to overcome the deficiencies of the above background technologies, the utility model provides a crane telescopic control system, which can improve safety.

[0010] The utility model is realized through the following technical solutions:

[0011] A crane telescopic control system, comprising:

[0012] The oil cylinder is provided with a first oil chamber and a second oil chamber, the first oil chamber is connected to the first oil circuit, and the second oil chamber is connected to the second oil circuit;

[0013] An oil tank, selectively connected to the first oil circuit or the second oil circuit through a reversing valve;

[0014] A balancing valve is provided in the first oil circuit, so that the oil from the oil tank to the first oil chamber can pass freely, and the oil from the first oil chamber to the oil tank is controlled by the pressure of the pilot port of the balancing valve, and the pilot port is connected to the second oil circuit through the third oil circuit;

[0015] The third oil circuit is provided with a first proportional reversing valve and a second proportional reversing valve, the first proportional reversing valve is closer to the pilot port than the second proportional reversing valve, and the first proportional reversing valve and the second proportional reversing valve are also connected to the oil tank through the fourth oil circuit respectively;

[0016] The crane telescopic control system also includes a damper, which is connected to the third oil circuit and the fourth oil circuit through a fifth oil circuit, and the connection between the fifth oil circuit and the third oil circuit is closer to the pilot port than the first proportional reversing valve.

[0017] Furthermore, a proportional relief valve and a throttle valve are arranged in parallel on the second oil circuit.

[0018] Furthermore, the third oil circuit is further provided with a filter, and the filter is closer to the second oil circuit than the second proportional reversing valve.

[0019] Furthermore, the fifth oil circuit is also provided with a one-way valve, and the one-way valve restricts the oil from flowing from the third oil circuit to the fourth oil circuit.

[0020] Furthermore, the fourth oil circuit is also provided with a one-way valve, and the one-way valve prevents the oil from flowing to the first proportional reversing valve.

[0021] Further, the first oil chamber is a rodless chamber, and the second oil chamber is a rodless chamber.

[0022] Furthermore, the first oil chamber and the second oil chamber are respectively provided with oil pressure sensors.

[0023] The beneficial effects of the utility model are:

[0024] 1. The main arm is in a loaded and suspended state, which effectively avoids the problem of high oil return back pressure, causing the balance valve to open and the cylinder to retract.

[0025] 2. The balancing valve control oil port adopts triple protection to ensure that the balancing valve pilot oil port can return oil in time, effectively ensuring the safety of load extension and retraction.

[0026] 3. When the cylinder retracts, the opening of the balance valve is controlled by electric proportional control to adjust the load-bearing retraction speed.

[0027] 4. When the cylinder is extended, the extension speed is controlled by adjusting the current value of the electric proportional relief valve. When the main arm is loaded, it can be extended slowly, and when the main arm is unloaded, it can be extended quickly. It is suitable for various lifting needs and improves efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the hydraulic connection of the crane telescopic control system according to an embodiment of the present application.

[0029] Reference numerals:

[0030] 1. Reversing valve; 2. Filter; 3. Electric proportional reversing valve; 4. Electric proportional reversing valve, 5. Electric proportional overflow valve; 6. Throttle valve; 7. Oil pressure sensor for large chamber of oil cylinder; 8. Oil pressure sensor for small chamber; 9. Check valve; 10. Damping; 11. Balance valve; 12. Oil cylinder. DETAILED DESCRIPTION

[0031] The utility model is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and cannot be used to limit the protection scope of the utility model.

[0032] A crane telescopic control system, comprising:

[0033] The oil cylinder 12 is provided with a first oil chamber and a second oil chamber, the first oil chamber is connected to the first oil circuit, and the second oil chamber is connected to the second oil circuit;

[0034] The oil tank is selectively connected to the first oil circuit or the second oil circuit through the reversing valve 1;

[0035] The balancing valve 11 is arranged in the first oil circuit, so that the oil from the oil tank to the first oil chamber can pass freely. The oil from the first oil chamber to the oil tank is controlled by the pressure of the pilot port of the balancing valve 11, and the pilot port is connected to the second oil circuit through the third oil circuit;

[0036] The third oil circuit is provided with a first proportional reversing valve 4 and a second proportional reversing valve 3, the first proportional reversing valve 4 is closer to the pilot port than the second proportional reversing valve 3, and the first proportional reversing valve 4 and the second proportional reversing valve 3 are also connected to the oil tank through a fourth oil circuit respectively;

[0037] The crane telescopic control system further includes a damper 10 , which is connected to the third oil circuit and the fourth oil circuit via a fifth oil circuit. The connection between the fifth oil circuit and the third oil circuit is closer to the pilot port than the first proportional reversing valve 4 .

[0038] Furthermore, a proportional relief valve 5 and a throttle valve 6 are arranged in parallel on the second oil circuit.

[0039] Furthermore, the third oil circuit is further provided with a filter 2 , and the filter 2 is closer to the second oil circuit than the second proportional reversing valve 3 .

[0040] Furthermore, the fifth oil circuit is also provided with a one-way valve 9, and the one-way valve restricts the oil from flowing from the third oil circuit to the fourth oil circuit.

[0041] Furthermore, the fourth oil circuit is also provided with a one-way valve, and the one-way valve prevents the oil from flowing to the first proportional reversing valve.

[0042] Furthermore, the first oil chamber is a rodless chamber (large chamber), and the second oil chamber has a rodless chamber (small chamber).

[0043] Furthermore, the first oil chamber and the second oil chamber are respectively provided with oil pressure sensors.

[0044] The specific control method of the crane telescopic control system is as follows:

[0045] The solenoid valve is energized and de-energized to control the reversing of the reversing valve 1, switching the extension and retraction state of the oil cylinder 12. After the solenoid valve is energized, the P port and the B port of the reversing valve 1 are connected, and the oil passes through the balance valve 11 and enters the large cavity of the oil cylinder 12, so that the piston rod of the oil cylinder 12 extends outward.

[0046] The throttle valve 6 and the electric proportional relief valve 5 are connected to the main oil return line (second oil line) of the oil cylinder 12. When the main arm needs to be extended slowly with load, the electric proportional relief valve 5 gives a large current value, and the oil returns slowly from the throttle port. When the main arm needs to be extended quickly without load, the electric proportional relief valve 5 gives a small current value, and the oil returns from the throttle port and the relief valve 5. The extension speed of the oil cylinder 12 is controlled by adjusting the current of the electric proportional relief valve 5.

[0047] The solenoid valve of reversing valve 1 is energized, so that the P port and A port of reversing valve 1 are connected, and oil enters the piston rod chamber of oil cylinder 12 to control the retraction of the main arm. The oil on the main oil circuit (second oil circuit) is supplied to the pilot port of the balance valve 11 through the filter 2, and the opening of the balance valve 11 is controlled by the dual electric proportional valves 3 and 4, so that the retraction speed of the main arm under load can be controlled.

[0048] The double proportional solenoid valves 3 and 4 can effectively protect the state of the oil cylinder 12 retracting and hovering. When the oil cylinder 12 stops retracting, the oil return from the pilot port of the balance valve 11 has multiple protection states. When the electric proportional valve 4 is stuck, the control oil of the pilot port of the balance valve 11 returns from valve 3, the electric proportional valve 3 is stuck, the control oil returns from valve 4, valves 4 and 5 are stuck, and the pilot oil returns from damping 6 and check valve 9. The multiple oil return protection methods can effectively ensure the safety of the oil cylinder 12 when it is retracted, especially the safety of the retraction of the main arm under load.

[0049] The crane telescopic control system can achieve the following effects:

[0050] 1. The dual proportional solenoid valve can effectively protect the cylinder from retracting and hovering;

[0051] 2. The balancing valve control oil port adopts triple protection to ensure that the balancing valve pilot oil port can return oil in time, effectively ensuring the safety of load extension and retraction.

[0052] 3. When the cylinder retracts, the opening of the balance valve is controlled by electric proportion to adjust the retraction speed under load. When the cylinder extends, the extension speed is controlled by adjusting the current value of the electric proportion relief valve. When the main arm is loaded, it can be extended slowly, and when the main arm is unloaded, it can be extended quickly, which is suitable for various lifting needs and improves efficiency.

[0053] The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A crane telescopic control system, comprising: The oil cylinder is provided with a first oil chamber and a second oil chamber, the first oil chamber is connected to the first oil circuit, and the second oil chamber is connected to the second oil circuit; An oil tank, selectively connected to the first oil circuit or the second oil circuit through a reversing valve; A balancing valve is provided in the first oil circuit, so that the oil from the oil tank to the first oil chamber can pass freely, and the oil from the first oil chamber to the oil tank is controlled by the pressure of the pilot port of the balancing valve, and the pilot port is connected to the second oil circuit through the third oil circuit; It is characterized in that the third oil circuit is provided with a first proportional reversing valve and a second proportional reversing valve, the first proportional reversing valve is closer to the pilot port than the second proportional reversing valve, and the first proportional reversing valve and the second proportional reversing valve are also connected to the oil tank through the fourth oil circuit respectively; The crane telescopic control system also includes a damper, which is connected to the third oil circuit and the fourth oil circuit through a fifth oil circuit, and the connection between the fifth oil circuit and the third oil circuit is closer to the pilot port than the first proportional reversing valve.

2. The crane telescopic control system according to claim 1, characterized in that: A proportional relief valve and a throttle valve are also arranged in parallel on the second oil circuit.

3. The crane telescopic control system according to claim 1, characterized in that: The third oil circuit is further provided with a filter, and the filter is closer to the second oil circuit than the second proportional reversing valve.

4. The crane telescopic control system according to claim 1, characterized in that: The fifth oil circuit is also provided with a one-way valve, and the one-way valve restricts the oil from flowing from the third oil circuit to the fourth oil circuit.

5. The crane telescopic control system according to claim 4, characterized in that: The fourth oil circuit is also provided with a one-way valve, which prevents oil from flowing to the first proportional reversing valve.

6. The crane telescopic control system according to claim 1, characterized in that: The first oil chamber is a rodless chamber, and the second oil chamber is a rodless chamber.

7. The crane telescopic control system according to claim 6, characterized in that: The first oil chamber and the second oil chamber are respectively provided with oil pressure sensors.

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