A crane luffing debugging hydraulic system

Abstract

The application provides a crane luffing debugging hydraulic system, in a luffing descending process, through a reversing valve, hydraulic oil of a main oil way of an oil pump flows to a second oil way through the reversing valve, and the hydraulic oil flow into the second oil way is adjusted through the reversing valve, since a pressure relief oil way is connected with the main oil way of the oil pump, the pressure of the main oil way of the oil pump supplied to the reversing valve is controlled by adjusting the pressure relief oil way, and then the pressure of the flow from the reversing valve to the second oil way is controlled, so that the opening of a balance valve is controlled through a branch oil way connected with the second oil way, the opening of the balance valve is matched with the flow of the hydraulic oil in a cylinder flowing out through the balance valve, finally, the hydraulic oil flows back to an oil tank through a first oil way, smooth descending is realized, and the oil way design structure is simple and the control is accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cranes, in particular to a crane luffing debugging hydraulic system. BACKGROUND

[0002] In the actual operation process of the crane, different working conditions will occur in different scenes, such as luffing up, static state, luffing down, etc., and in different working conditions, the speed of the crane needs to be controlled to prevent the speed of lifting or lowering the load from being too fast to cause safety accidents. To solve this technical problem, a crane luffing control system and its control method are disclosed in Chinese patent application No. 202310491306.0, published on July 25, 2023, which comprises a luffing cylinder, a luffing handle, a hydraulic oil tank, an oil pump, a balance valve, a pressure sensor and a controller. The rodless cavity of the luffing cylinder is connected with the C port of the balance valve. The A1 port of the balance valve is connected with the oil pump and the hydraulic oil tank in turn. The pressure sensor is connected with the rodless cavity of the luffing cylinder for detecting the oil pressure P of the rodless cavity of the luffing cylinder and sending the collected oil pressure value P to the controller. The controller is used for receiving the working signal transmitted by the luffing handle and the oil pressure value P monitored by the pressure sensor in real time, and realizing real-time control of the oil pump displacement and the balance valve opening degree according to the preset control strategy.

[0003] In the above-mentioned document, the pressure value P of the rodless cavity of the luffing cylinder measured by the pressure sensor is compared with the preset pressure value, and then the maximum opening of the oil pump displacement and the balance valve is controlled, so as to improve the stability and safety of luffing down. However, if the pressure sensor is affected due to unstable factors of the circuit, the measured data will be inaccurate, and the control process needs to be realized by the cooperation of the oil pump displacement and the opening of the balance valve, but it cannot be realized according to the pressure situation. The control method is complex, so that the flow of hydraulic oil cannot be accurately controlled. SUMMARY

[0004] The purpose of the present application is to provide a crane luffing debugging hydraulic system, which can adjust the pressure of the balance valve connected with the main oil circuit of the oil pump by releasing the local pressure in the main oil circuit of the oil pump during the luffing process, so as to realize smooth descent. The oil circuit design structure is simple and the control is accurate.

[0005] To achieve the above object, a crane luffing debugging hydraulic system, comprising a pump main oil circuit, a reversing valve, a pressure relief oil circuit, a first oil circuit, a second oil circuit and a cylinder, the pump main oil circuit is connected with the pressure relief oil circuit and the reversing valve respectively, the P1 valve port of the reversing valve is connected with one end of the first oil circuit, the P2 valve port of the reversing valve is connected with one end of the second oil circuit, the P2 valve port of the reversing valve is communicated with the pump main oil circuit after reversing, the P1 port of the reversing valve is communicated with the A port, a balance valve is arranged between the first oil circuit and the cylinder, the other end of the first oil circuit and one end of the cylinder are connected with the balance valve respectively, the other end of the second oil circuit and the other end of the cylinder are connected, a branch oil circuit is arranged between the second oil circuit and the balance valve, the pump main oil circuit and the pressure relief oil circuit are connected with the oil tank.

[0006] The above arrangement can make the hydraulic oil of the pump main oil circuit flow to the second oil circuit through the reversing valve during luffing descent, and the hydraulic oil flow into the second oil circuit is adjusted through the reversing valve, the pressure of the pump main oil circuit is controlled by adjusting the pressure relief oil circuit due to the connection between the pressure relief oil circuit and the pump main oil circuit, and then the pressure from the reversing valve to the second oil circuit is controlled, the opening of the balance valve is controlled through the branch oil circuit connected with the second oil circuit, and the pressure relief of the pressure relief oil circuit is realized only by controlling the reversing of the reversing valve, so that the opening of the balance valve matches the flow of the hydraulic oil in the cylinder through the balance valve, and finally the hydraulic oil flows back to the oil tank through the first oil circuit, realizing smooth descent, and the control method is simple and reliable.

[0007] Further, the pump main oil circuit comprises a pump and a third oil circuit connected with the pump, one end of the third oil circuit is connected with the oil outlet of the pump, the oil inlet of the pump is connected with the oil tank, and the pump is connected with the output end of a motor arranged outside the pump.

[0008] The above arrangement can control the work of the pump through the motor to extract the hydraulic oil in the oil tank into the third oil circuit.

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

[0010] The above arrangement can adjust the pressure flowing through the reversing valve through the stroke of the valve core.

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

[0012] The above arrangement can make the first pressure valve open and communicate with the return filter when pressure relief is performed through the pressure relief oil circuit, and then make part of the hydraulic oil in the pump main oil circuit flow back to the oil tank through the first pressure valve and the return filter.

[0013] Further, a pressure valve group is arranged at the A valve port of the reversing valve and the B valve port of the reversing valve, the pressure valve group comprising a second pressure valve and a third pressure valve, one end of the second pressure valve being connected with the A valve port of the reversing valve, one end of the third pressure valve being connected with the B valve port of the reversing valve, the other end of the second pressure valve and the other end of the third pressure valve being connected with the oil return 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 released by the pressure valve group, so that the local hydraulic oil flows to the oil return filter through the pressure valve group, preventing the damage of the reversing valve caused by excessive pressure.

[0015] Further, the oil return filter comprises a pressure gauge, a filter and a one-way valve, the one-way valve being connected in parallel at both ends of the filter, the rear end of the filter being connected with the oil tank, and the pressure gauge being connected at the front end of the filter.

[0016] With the above arrangement, the oil pressure entering the filter can be monitored by the pressure gauge, and the local hydraulic oil can be shunted by the one-way valve, thereby avoiding the damage of the filter caused by excessive oil pressure.

[0017] Further, the oil cylinder is a single piston rod oil cylinder, the single piston rod oil cylinder being internally provided with a single piston rod, the single piston rod dividing the oil cylinder into a first chamber and a second chamber, the first chamber being in communication with the balance valve, and the second chamber being in communication with the other end of the second oil circuit.

[0018] With the above arrangement, the first oil circuit is connected with the first chamber through the balance valve, and the second oil circuit is connected with the second chamber, so as to push the single piston rod to move in the oil cylinder, thereby realizing the amplitude lifting. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure is a schematic diagram of the hydraulic system of the present application.

[0020] Figure 2 The figure is a schematic diagram of the hydraulic system of the present application. Figure 1 The figure is an enlarged view of E in the middle.

[0021] Figure 3 The figure is an enlarged view of E in the middle. Figure 1 The figure is an enlarged view of F in the middle. DETAILED DESCRIPTION

[0022] The present application will be further described in detail below in combination with the drawings and specific embodiments.

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

[0024] The pressure relief oil circuit 3 includes a first pressure valve 31 and an oil return filter, one end of the first pressure valve 31 is connected with the other end of the third oil circuit 13, the other end of the first pressure valve 31 is connected with the A valve port of the reversing valve 2, the B valve port of the reversing valve 2 and the oil return filter respectively, the oil return filter is connected with the oil tank 6, a pressure valve group is arranged at the A valve port of the reversing valve 2 and the B valve port of the reversing valve 2, in this embodiment, the pressure of the flow 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, so that when the hydraulic oil pressure through the reversing valve 2 reaches a fixed value, the pressure relief through the pressure relief oil circuit 3 can be carried out, the first pressure valve 31 can be opened to communicate with the oil return filter, and then the local hydraulic oil in the oil pump main oil circuit 1 can flow back to the oil tank 6 through the first pressure valve 31 and the oil return 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 with the A valve port of the reversing valve 2, one end of the third pressure valve 43 is connected with the B valve port of the reversing valve 2, the other end of the second pressure valve 42 and the other end of the third pressure valve 43 are connected with the oil return filter, so that 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 relieved through the pressure valve group, so that the local hydraulic oil flows to the oil return filter through the pressure valve group and finally flows back to the oil tank 6, preventing the reversing valve 2 from being damaged due to excessive pressure.

[0025] The oil return 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 with the oil tank 6, and the pressure gauge 7 is connected at the front end of the filter 8, so as to facilitate monitoring the oil pressure entering the filter 8 through the pressure gauge 7, and the local hydraulic oil can be shunted through the one-way valve 9, thereby avoiding damage to the filter 8 due to excessive oil pressure.

[0026] The P1 valve port of the reversing valve 2 is connected with one end of the first oil path 4, the P2 valve port of the reversing valve 2 is connected with one end of the second oil path 5, the balance valve 10 is arranged between the first oil path 4 and the oil cylinder 60, the oil distribution path 20 is arranged between the second oil path 4 and the balance valve 10, the balance valve 10 is connected with the other end of the first oil path 4 and one end of the oil cylinder 60, the other end of the second oil path 5 and the other end of the oil cylinder 60 respectively, the P2 valve port of the reversing valve 2 is communicated with the oil pump main oil path 1 after reversing, the P1 valve port of the reversing valve is communicated with the A port, in the embodiment, the oil cylinder 60 is a single piston rod oil cylinder, the single piston rod oil cylinder is internally provided with a single piston rod 603, the single piston rod 603 divides the oil cylinder 60 into a first chamber 601 and a second chamber 602, the first chamber 601 is communicated with the balance valve 10, the second chamber 602 is communicated with the other end of the second oil path 5, so that the first oil path 4 is connected with the first chamber 601 through the balance valve 10, the second oil path 5 is connected with the second chamber 602, and then the single piston rod 603 can be pushed to move in the oil cylinder 60, so that the amplitude lifting is realized, in the embodiment, the first chamber 601 and the second chamber 602 are filled with hydraulic oil.

[0027] The working principle of the present application is as follows: in the amplitude descending process, the reversing valve 2 is reversed, so that the hydraulic oil of the oil pump main oil path 1 is reversed to the B valve port through the reversing valve 2, the oil pump main oil path 1 flows to the second oil path 5, the hydraulic oil flow entering the second oil path 2 is adjusted through the reversing valve 2, the first oil path 4 enters the second pressure valve 42 through the A port, so that the second pressure valve 42 is opened and then pressure relief, since the pressure relief oil path 3 is connected with the oil pump main oil path 1, the pressure entering the pressure relief oil path 3 is adjusted by adjusting the pressure value of the first pressure valve 31 in the pressure relief oil path 3, so as to control the pressure of the oil pump main oil path 1 supplied to the reversing valve 2, and then control the pressure flowing out from the reversing valve 2 to the second oil path 5, so as to control the opening degree of the balance valve 10 through the oil distribution path connected with the second oil path 5, so that the opening degree of the balance valve 10 matches the flow of the hydraulic oil in the oil cylinder flowing out through the balance valve 10, and finally flows back to the oil tank through the first oil path 4, so as to realize smooth descending.

Claims

1. A hydraulic system for adjusting the luffing speed of a crane, 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. The P1 port of the reversing valve is connected to one end of the first oil circuit, and the P2 port of the reversing valve is connected to one end of the second oil circuit. After reversing, the P2 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 port A. A balance valve is provided between the first oil circuit and the oil cylinder. The balance valve is 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. A branch oil circuit is provided between the second oil circuit and the balance valve. The main oil circuit of the oil pump and the pressure relief oil circuit are both connected to the oil tank. The pressure entering the pressure relief oil circuit is adjusted by adjusting the pressure value of the first pressure valve in the pressure relief oil circuit, and the pressure distributed by the main oil circuit of the oil pump to the reversing valve is controlled to control the pressure flowing out of the reversing valve to the second oil circuit. The opening of the balance valve is controlled by the branch oil circuit connected to the second oil circuit, so that the opening of the balance valve matches the flow rate of the hydraulic oil in the oil cylinder flowing out of the balance valve. Finally, the oil flows back to the oil tank through the first oil circuit.

2. The hydraulic system for adjusting the luffing angle of a crane 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 a motor located outside the oil pump.

3. The hydraulic system for adjusting the luffing speed of a crane according to claim 1, characterized in that: The stroke of the directional valve spool is adjusted by moving a handle located outside the directional valve.

4. The hydraulic system for adjusting the luffing speed of a crane according to claim 1, characterized in that: 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 connected to the A port of the reversing valve, the B port of the reversing valve, and the return oil filter, respectively. The return oil filter is connected to the oil tank.

5. The hydraulic system for adjusting the luffing angle of a crane according to claim 1, characterized in that: A pressure valve assembly is provided at the A port and the B port of the directional valve. The pressure valve assembly includes a second pressure valve and a third pressure valve. One end of the second pressure valve is connected to the A port of the directional valve, and one end of the third pressure valve is connected to the B port of the directional valve. The other ends of the second and third pressure valves are both connected to the return oil filter.

6. The hydraulic system for adjusting the luffing speed of a crane according to claim 5, characterized in that: The return oil filter includes a pressure gauge, a filter, and a check valve. The check valve is connected in parallel to 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 adjusting the luffing angle of a crane according to claim 1, characterized in that: The cylinder is a single-piston rod cylinder. The single-piston rod is provided inside the cylinder, which divides the 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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