Variable-amplitude debugging hydraulic system for crane

Abstract

According to the crane variable-amplitude debugging hydraulic system, in the variable-amplitude descending process, reversing is conducted through the reversing valve, so that hydraulic oil of the oil pump main oil way flows to the second oil way through the reversing valve, and meanwhile the flow of the hydraulic oil flowing into the second oil way is adjusted through the reversing valve; the pressure relief oil way is adjusted to control the pressure distributed to the reversing valve by the oil pump main oil way, and then the pressure flowing out of the reversing valve to the second oil way is controlled, so that the opening degree of the balance valve is controlled through the branch oil way connected with the second oil way, and the opening degree of the balance valve is matched with the flow of hydraulic oil flowing out of the balance valve in the oil cylinder; and stable descending is achieved, the oil way design structure is simple, and control is accurate.

Description

Technical Field

[0001] The invention relates to the technical field of cranes, and in particular to a hydraulic system for adjusting the luffing speed of a crane. Background Art

[0002] In the actual operation of the crane, there will be different working conditions in different scenarios, such as luffing, static state, luffing, etc. In different working conditions, it is necessary to control the speed of the crane rising or falling to avoid lifting or lowering the load too fast and causing safety accidents. In order to solve this technical problem, a patent document with Chinese patent application number 202310491306.0 and publication date 2023.07.25 discloses a crane luffing control system and a control method thereof, including a luffing cylinder, a luffing handle, and a hydraulic oil. The invention relates to a hydraulic cylinder comprising a rodless chamber, an oil pump, a balancing valve, a pressure sensor and a controller; the rodless chamber of the luffing cylinder is connected to the C port of the balancing valve; the A1 port of the balancing valve is connected to the oil pump and the hydraulic oil tank in sequence; the pressure sensor is connected to the rodless chamber of the luffing cylinder to detect the oil pressure P of the rodless chamber of the luffing cylinder, and send the collected oil pressure value P to the controller; the controller is used to receive the working signal transmitted by the luffing handle and the oil pressure value P monitored in real time by the pressure sensor, and realize real-time control of the oil pump displacement and the opening of the balancing valve according to the preset control strategy.

[0003] In the above-mentioned document, the pressure value P of the rodless chamber of the boom cylinder measured by the pressure sensor is compared with the preset pressure value, and then the oil pump displacement and the maximum opening of the balance valve are controlled, so as to improve the stability and safety of the boom drop; but if the pressure sensor is affected by the unstable factors of the circuit, the measured data is likely to be inaccurate, and the control process needs to be controlled by the coordination of the oil pump displacement and the opening of the balance valve, and it is impossible to achieve follow-up control according to the pressure situation. The control method is complicated, and it is impossible to achieve precise control of the flow of hydraulic oil. Summary of the invention

[0004] The purpose of the present invention is to provide a crane luffing debugging hydraulic system. During the luffing process, the local pressure in the main oil circuit of the oil pump is unloaded, thereby adjusting the pressure of the balance valve connected to the main oil circuit of the oil pump, thereby achieving a smooth descent. The oil circuit design structure is simple and the control is accurate.

[0005] To achieve the above-mentioned purpose, a hydraulic system for crane luffing and debugging includes an oil pump main oil circuit, a reversing valve, a pressure relief oil circuit, a first oil circuit, a second oil circuit and an oil cylinder, wherein the oil pump main oil circuit is respectively connected to the pressure relief oil circuit and the reversing valve, the P1 valve port of the reversing valve is connected to one end of the first oil circuit, the P2 valve port of the reversing valve is connected to one end of the second oil circuit, the P2 valve port of the reversing valve is connected to the main oil circuit of the oil pump after reversing, the P1 port of the reversing valve is connected to the A port, a balancing valve is provided between the first oil circuit and the oil cylinder, the balancing valve is respectively connected to the other end of the first oil circuit and one end of the oil cylinder, the other end of the second oil circuit is connected to the other end of the oil cylinder, an oil branch circuit is provided between the second oil circuit and the balancing valve, and the oil pump main oil circuit and the pressure relief oil circuit are both connected to the oil tank.

[0006] With the above arrangement, during the variable amplitude descending process, the reversing valve is used to reverse the direction, so that the hydraulic oil in the main oil circuit of the oil pump can flow to the second oil circuit through the reversing valve, and the hydraulic oil flow flowing into the second oil circuit is adjusted by the reversing valve. Since the pressure relief oil circuit is connected to the main oil circuit of the oil pump, the pressure of the main oil circuit of the oil pump distributed to the reversing valve can be controlled by adjusting the pressure relief oil circuit, and then the pressure flowing from the reversing valve to the second oil circuit can be controlled, so as to control the opening of the balancing valve through the oil branch circuit connected to the second oil circuit. It is only necessary to control the reversing of the reversing valve to realize the pressure relief oil circuit to relieve the pressure, so that the opening of the balancing valve matches the flow rate of the hydraulic oil in the cylinder flowing out through the balancing valve, and finally flows back to the oil tank through the first oil circuit to achieve a smooth descent. The control method is simple and reliable.

[0007] Furthermore, the main oil circuit of the oil pump includes an oil pump and a third oil circuit connected to the oil pump, one end of the third oil circuit is connected to the oil outlet of the oil pump, the oil inlet of the oil pump is connected to the oil tank, and the oil pump is connected to the output end of the motor arranged outside the oil pump.

[0008] The above arrangement can control the oil pump to work through the motor, and draw the hydraulic oil from the oil tank into the third oil circuit.

[0009] Furthermore, the stroke of the valve core of the reversing valve is adjusted by moving a handle arranged outside the reversing valve.

[0010] With the above arrangement, the pressure flowing through the reversing valve can be adjusted by the valve core stroke.

[0011] Furthermore, the pressure relief oil circuit includes a first pressure valve and a return oil filter, one end of the first pressure valve is connected to the other end of the third oil circuit, the other end of the first pressure valve is respectively connected to the A valve port of the reversing valve, the B valve port of the reversing valve and the return oil filter, and the return oil filter is connected to the oil tank.

[0012] The above arrangement enables the first pressure valve to be opened and connected to the return oil filter when the pressure is relieved through the pressure relief oil circuit, thereby allowing the local hydraulic oil in the main oil circuit of the oil pump to flow back to the oil tank through the first pressure valve and the return oil filter.

[0013] Furthermore, a pressure valve group is provided at the valve port A of the reversing valve and the valve port B of the reversing valve, and the pressure valve group includes a second pressure valve and a third pressure valve, one end of the second pressure valve is connected to the valve port A of the reversing valve, one end of the third pressure valve is connected to the valve port B of the reversing valve, and the other end of the second pressure valve and the other end of the third pressure valve are both connected to the return oil filter.

[0014] With the above arrangement, when the hydraulic oil in the first oil circuit flows back to the reversing valve, the local pressure of the reversing valve can be relieved through the pressure valve group, so that the local hydraulic oil flows through the pressure valve group to the return oil filter, thereby preventing the reversing valve from being damaged by excessive pressure.

[0015] Furthermore, the oil return filter includes a pressure gauge, a filter and a one-way valve, the one-way valve is connected in parallel at both ends of the filter, the rear end of the filter is connected to the oil tank, and the pressure gauge is connected to the front end of the filter.

[0016] The above arrangement facilitates monitoring of the oil pressure entering the filter through a pressure gauge, and can simultaneously divert local hydraulic oil through a one-way valve, thereby preventing the filter from being damaged by excessive oil pressure.

[0017] Furthermore, the oil cylinder is a single-piston rod oil cylinder, and a single piston rod is provided inside the single-piston rod oil cylinder. The single piston rod divides the interior of the oil cylinder into a first chamber and a second chamber. The first chamber is connected to the balance valve, and the second chamber is connected to the other end of the second oil circuit.

[0018] The above arrangement enables the first oil circuit to be connected to the first chamber through the balance valve, and the second oil circuit to be connected to the second chamber, thereby pushing the single piston rod to move in the oil cylinder, thereby achieving variable amplitude lifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the connection of the hydraulic system of the present invention.

[0020] Figure 2 for Figure 1 Enlarged view of point E in the middle.

[0021] Figure 3 for Figure 1 Enlarged view of point F in the middle. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-3As shown, a hydraulic system for crane luffing commissioning includes an oil pump main oil circuit 1, a reversing valve 2, a pressure relief oil circuit 3, a first oil circuit 4, a second oil circuit 5 and an oil cylinder 60. The oil pump main oil circuit 1 is connected to the pressure relief oil circuit 3 and the reversing valve 2 respectively, and the oil pump main oil circuit 1 and the pressure relief oil circuit 4 are both connected to the oil tank 6. The oil pump main oil circuit 1 includes an oil pump 11 and a third oil circuit 13 connected to the oil pump 11, one end of the third oil circuit 13 is connected to the oil outlet C of the oil pump 11, and the oil inlet D of the oil pump 11 is connected to the oil tank 6. The oil pump 11 is connected to the output end of a motor 12 arranged on the outside of the oil pump 11, so that the oil pump 11 can be controlled to work through the motor 12, and the hydraulic oil of the oil tank 6 is drawn into the third oil circuit 13.

[0024] The pressure relief oil circuit 3 includes a first pressure valve 31 and a return oil filter. One end of the first pressure valve 31 is connected to the other end of the third oil circuit 13. The other end of the first pressure valve 31 is respectively connected to the valve port A of the reversing valve 2, the valve port B of the reversing valve 2 and the return oil filter. The return oil filter is connected to the oil tank 6. A pressure valve group is provided at the valve port A of the reversing valve 2 and the valve port B of the reversing valve 2. In this embodiment, the pressure flowing through the reversing valve 2 can be adjusted by moving the handle arranged outside the reversing valve 2 to adjust the stroke of the valve core of the reversing valve 2. When the pressure of the hydraulic oil passing through the reversing valve 2 reaches a fixed value, the pressure is relieved through the pressure relief oil circuit 3, so that the first pressure valve 31 can be opened and connected to the return oil circuit. The filter is connected, so that the local hydraulic oil in the main oil circuit 1 of the oil pump flows back to the oil tank 6 through the first pressure valve 31 and the return oil filter; the pressure valve group includes a second pressure valve 42 and a third pressure valve 43, one end of the second pressure valve 42 is connected to the valve port A of the reversing valve 2, one end of the third pressure valve 43 is connected to the valve port B of the reversing valve 2, and the other end of the second pressure valve 42 and the other end of the third pressure valve 43 are both connected to the return oil filter. In this way, when the hydraulic oil in the first oil circuit 4 flows back to the reversing valve 2, the local pressure of the reversing valve 2 can be unloaded through the pressure valve group, so that the local hydraulic oil flows to the return oil filter through the pressure valve group, and finally flows back to the oil tank 6, so as to prevent the reversing valve 2 from being damaged by excessive pressure.

[0025] The return oil filter includes a pressure gauge 7, a filter 8 and a one-way valve 9. The one-way valve 9 is connected in parallel at both ends of the filter 8. The rear end of the filter 8 is connected to the oil tank 6, and the pressure gauge 7 is connected to the front end of the filter 8, so that the oil pressure entering the filter 8 can be monitored by the pressure gauge 7. At the same time, the local hydraulic oil can be diverted through the one-way valve 9 to avoid damage to the filter 8 due to excessive oil pressure.

[0026] The P1 valve port of the reversing valve 2 is connected to one end of the first oil circuit 4, and the P2 valve port of the reversing valve 2 is connected to one end of the second oil circuit 5. A balancing valve 10 is provided between the first oil circuit 4 and the oil cylinder 60, and a branch oil circuit 20 is provided between the second oil circuit 4 and the balancing valve 10. The balancing valve 10 is connected through the branch oil circuit 20. The balancing valve 10 is respectively connected to the other end of the first oil circuit 4 and one end of the oil cylinder 60, and the other end of the second oil circuit 5 is connected to the other end of the oil cylinder 60. After the reversing, the P2 valve port of the reversing valve 2 is connected to the main oil circuit 1 of the oil pump, and the P1 port of the reversing valve is connected to the A port. In this embodiment, the oil cylinder 60 is A single-piston rod cylinder, a single piston rod 603 is provided inside the single-piston rod cylinder, the single piston rod 603 divides the inside of the cylinder 60 into a first chamber 601 and a second chamber 602, the first chamber 601 is connected to the balance valve 10, and the second chamber 602 is connected to the other end of the second oil circuit 5, so that the first oil circuit 4 can be connected to the first chamber 601 through the balance valve 10, and the second oil circuit 5 is connected to the second chamber 602, thereby pushing the single piston rod 603 to move in the cylinder 60, thereby realizing variable amplitude lifting. In this embodiment, the first chamber 601 and the second chamber 602 are filled with hydraulic oil.

[0027] Working principle of the present invention: During the variable amplitude descending process, the reversing valve 2 is used for reversing, so that the hydraulic oil in the main oil circuit 1 of the oil pump is switched to the valve port B through the reversing valve 2, so that the main oil circuit 1 of the oil pump flows to the second oil circuit 5, and at the same time, the hydraulic oil flow flowing into the second oil circuit 2 is adjusted by the reversing valve 2, and at the same time, the first oil circuit 4 enters the second pressure valve 42 through the A port so that the second pressure valve 42 opens and then relieves the pressure. Since the pressure relief oil circuit 3 is connected to the main oil circuit 1 of the oil pump, the pressure entering the pressure relief oil circuit 3 is adjusted by adjusting the pressure value of the first pressure valve 31 in the pressure relief oil circuit 3, so as to control the pressure distributed to the reversing valve 2 by the main oil circuit 1 of the oil pump, and then control the pressure flowing out of the reversing valve 2 to the second oil circuit 5, so as to control the opening of the balance valve 10 through the branch oil circuit connected to the second oil circuit 5, so that the opening of the balance valve 10 matches the flow of the hydraulic oil in the cylinder flowing out through the balance valve 10, and finally flows back to the oil tank through the first oil circuit 4 to achieve a smooth descent.

Claims

1. A hydraulic system for crane luffing and debugging, comprising a main oil circuit of an oil pump, a reversing valve, a pressure relief oil circuit, a first oil circuit, a second oil circuit and an oil cylinder, characterized in that: The main oil circuit of the oil pump is connected to the pressure relief oil circuit and the reversing valve respectively. The P1 valve port of the reversing valve is connected to one end of the first oil circuit, and the P2 valve port of the reversing valve is connected to one end of the second oil circuit. After the reversing, the P2 valve port of the reversing valve is connected to the main oil circuit of the oil pump, and the P1 port of the reversing valve is connected to the A port. A balancing valve is provided between the first oil circuit and the oil cylinder. The balancing valve is respectively connected to the other end of the first oil circuit and one end of the oil cylinder, and the other end of the second oil circuit is connected to the other end of the oil cylinder. An oil branch circuit is provided between the second oil circuit and the balancing valve. The main oil circuit of the oil pump and the pressure relief oil circuit are both connected to the oil tank.

2. A crane luffing adjustment hydraulic system according to claim 1, characterized in that: The main oil circuit of the oil pump includes an oil pump and a third oil circuit connected to the oil pump, one end of the third oil circuit is connected to the oil outlet of the oil pump, the oil inlet of the oil pump is connected to the oil tank, and the oil pump is connected to the output end of the motor arranged outside the oil pump.

3. A crane luffing adjustment hydraulic system according to claim 1, characterized in that: The stroke of the valve core of the reversing valve is adjusted by moving a handle arranged outside the reversing valve.

4. The hydraulic system for crane luffing and debugging according to claim 1 is characterized by: The pressure relief oil circuit includes a first pressure valve and a return oil filter, one end of the first pressure valve is connected to the other end of the third oil circuit, the other end of the first pressure valve is respectively connected to the A valve port of the reversing valve, the B valve port of the reversing valve and the return oil filter, and the return oil filter is connected to the oil tank.

5. The hydraulic system for crane luffing and debugging according to claim 1 is characterized by: A pressure valve group is provided at the valve port A of the reversing valve and the valve port B of the reversing valve, and the pressure valve group includes a second pressure valve and a third pressure valve, one end of the second pressure valve is connected to the valve port A of the reversing valve, one end of the third pressure valve is connected to the valve port B of the reversing valve, and the other end of the second pressure valve and the other end of the third pressure valve are both connected to the return oil filter.

6. A crane luffing adjustment hydraulic system according to claim 5, characterized in that: The oil return filter comprises a pressure gauge, a filter and a one-way valve, the one-way valve is connected in parallel at both ends of the filter, the rear end of the filter is connected to the oil tank, and the pressure gauge is connected to the front end of the filter.

7. The hydraulic system for crane luffing and debugging according to claim 1, characterized in that: The oil cylinder is a single-piston rod oil cylinder, and a single piston rod is arranged inside the single-piston rod oil cylinder. The single piston rod divides the inside of the oil cylinder into a first chamber and a second chamber. The first chamber is connected to the balance valve, and the second chamber is connected to the other end of the second oil circuit.

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