A lubrication control system and control method for a crane luffing mechanism

Abstract

This invention discloses a lubrication control system and method for a crane luffing mechanism. Based on a conventional crane luffing mechanism and lubrication oil pump station, a control system is established. This control system includes flow meters, single-channel solenoid valves, multi-channel solenoid valve groups, tilt sensors, a PLC controller, a frequency converter, and a lubrication oil pump control circuit, as well as a remote control handle. During luffing operation, the control system automatically controls the lubrication oil pump station to achieve synchronous lubrication of the luffing mechanism. During lubrication, flow meters on corresponding return oil lines are used to automatically detect blockages at different tilt angles, and clearing blockages when necessary. Furthermore, a delay control circuit ensures continuous lubrication during intermittent operation of the luffing mechanism, effectively reducing the number of start-stop cycles of the lubrication oil pump station, ensuring continuous lubrication of the luffing mechanism during operation, reducing oil spillage and leakage, and further lowering the failure rate of the luffing mechanism.

Description

Technical Field

[0001] This invention belongs to the field of crane technology, and in particular relates to a lubrication control system and control method for a crane luffing mechanism. Background Technology

[0002] Gantry cranes are widely used in shipbuilding and port loading and unloading, and the luffing mechanism is one of their main moving mechanisms. Currently, conventional lubrication systems are manually controlled, which cannot effectively coordinate with the luffing action. After prolonged operation, oil leaks and blockages occur, failing to provide effective lubrication. During high-frequency lifting, the lack of lubrication leads to severe wear and poor heat dissipation of transmission components, shortening the service life of the luffing mechanism. Furthermore, because the main load-bearing components of the luffing mechanism are enclosed within the telescopic sleeve, timely visual inspection is impossible, posing a significant safety risk.

[0003] Therefore, we consider developing an effective lubrication control system and control method for a crane luffing mechanism by combining a PLC controller with a tilt sensor.

[0004] A search revealed that Chinese invention document CN103629175B discloses a hydraulic control system for a work bucket and an engineering vehicle. The document states that "this invention discloses a hydraulic control system for a work bucket and an engineering vehicle. The control system includes a leveling cylinder and a leveling control circuit, a luffing cylinder and a luffing control circuit, and a booster cylinder and a booster oil circuit. The rod chamber oil circuit of the booster cylinder is connected to the main oil inlet circuit; the booster oil circuit is equipped with a first switch control valve and has a first bypass oil circuit hydraulically connected to the rod chamber of the luffing cylinder and a second bypass oil circuit hydraulically connected to the system oil tank and equipped with a second switch control valve." Although this invention also uses a tilt sensor, the tilt angle is only used as a condition for controlling the electro-proportional control valve to adjust the hydraulic oil flow to the leveling cylinder, which has certain limitations. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a lubrication control system and method for a crane luffing mechanism. This system automatically activates lubrication during luffing operations, synchronously linking with the luffing mechanism to achieve effective lubrication. Furthermore, the lubricating oil enhances heat dissipation in the transmission mechanism, further reducing wear. The system also features automatic start / stop functionality, ensuring high safety, effectively reducing crane downtime, and saving costs.

[0006] To achieve the above and other related objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a lubrication control system for a crane luffing mechanism. The luffing mechanism is connected to a lubricating oil pump station via an oil inlet pipe and an oil return pipe. The lubricating oil in the lubricating oil pump station is transported to the gearbox and drive components of the luffing mechanism via the oil inlet pipe, and returns to the lubricating oil pump station via the oil return pipe to form an oil supply pipeline. The oil return pipe includes a first oil return pipe, a second oil return pipe, and a third oil return pipe. The inlets of the first oil return pipe, the second oil return pipe, and the third oil return pipe are connected to the luffing mechanism and are distributed sequentially from the near end to the far end of the luffing mechanism. The luffing mechanism includes a drive motor, a gearbox, and a drive component. The lubrication control system includes a flow meter, a single-channel solenoid valve, a multi-channel solenoid valve group, a tilt sensor, a PLC controller, a frequency converter, and a lubricating oil pump control circuit.

[0008] The flow meter is installed on each return oil pipe; the single-channel solenoid valve is installed on each return oil pipe and the inlet oil pipe. The single-channel solenoid valve is electrically connected to the PLC controller and is controlled by the PLC controller to open or close the oil circuit in the pipeline.

[0009] The multi-way solenoid valve group adopts a one-in-three-out valve. The oil inlet pipe is connected to each oil return pipe through the multi-way solenoid valve group. The oil inlet of the multi-way solenoid valve group is connected to the oil inlet pipe and is located between the lubricating oil pump station and the single-way solenoid valve at the oil inlet pipe. The three oil outlets of the multi-way solenoid valve group are respectively connected to each oil return pipe and are located between the corresponding single-way solenoid valve and flow meter on each oil return pipe. The multi-way solenoid valve group is electrically connected to the PLC controller and is adjusted by the PLC controller switching the on and off of the oil outlets to adjust the lubricating oil circuit.

[0010] The tilt sensor is connected to the PLC controller via signal, and the frequency converter is electrically connected to the drive motor and the PLC controller respectively. The PLC controller collects the tilt signal measured by the tilt sensor in real time and processes the tilt signal into a control signal for output. The frequency converter receives the control signal sent by the PLC controller and controls the drive motor to rotate forward or reverse, so that the amplitude-changing mechanism can perform amplitude-increasing or amplitude-decreasing operations.

[0011] The lubricating oil pump control circuit includes a start relay and a delay control circuit connected in series. The delay control circuit includes an amplification relay, a deamping relay, and a delay disconnect relay. The amplification relay and the deamping relay are connected in parallel and then connected in series with the delay disconnect relay.

[0012] As a preferred technical solution, the control system further includes a remote control handle, which is electrically connected to the PLC controller. The remote control handle is used to control the start of the luffing mechanism and to control the luffing mechanism to perform luffing actions to change the angle of inclination.

[0013] A second aspect of the present invention provides a control method for any of the above-described lubrication control systems for a crane luffing mechanism, comprising the following steps:

[0014] S1. Determine if the luffing mechanism is in the starting state: When it is in the starting state, start the lubricating oil pump station simultaneously to provide lubrication for the luffing mechanism;

[0015] S2. During the operation of the luffing mechanism, the tilt angle is detected by the tilt sensor to determine the return oil pipe to be inspected. The tilt angle is the angle between the luffing mechanism and the horizontal plane. Then, the return oil status in the return oil pipe is detected by the flow meter. When there is no return oil in the return oil pipe, the return oil pipe is cleared. When clearing different return oil pipes, the lubricating oil circuit is adjusted by switching the on / off state of each oil outlet of each single solenoid valve and multi-way solenoid valve group.

[0016] S3. Determine whether the luffing mechanism is still in the starting state. When the luffing mechanism changes from starting to closing, delay shutting down the lubricating oil pump station.

[0017] As a preferred technical solution, in step S2, the specific steps of detecting the tilt angle using a tilt sensor and determining the return oil pipe to be inspected include:

[0018] When the tilt angle is ≤10°, check whether there is return oil in the third return oil pipe;

[0019] When 10° < tilt angle ≤ 20°, check whether there is return oil in the second return oil pipe;

[0020] When the tilt angle is greater than 20°, check whether there is return oil in the first return oil pipe.

[0021] As a preferred technical solution, in step S2, the specific steps for detecting the return oil status in the return oil pipe by means of a flow meter, and performing the unblocking operation of the return oil pipe when there is no return oil in the return oil pipe include: real-time monitoring of the flow value of the flow meter; when the flow value of the flow meter = 0, it indicates that there is no return oil in the return oil pipe where the flow meter is located, and it is determined that the current return oil pipe is blocked, and the unblocking operation of the current return oil pipe is performed.

[0022] As a preferred technical solution, in step S2, the specific steps of the unblocking operation of the return oil pipe include:

[0023] S2-1. Control the luffing mechanism to perform luffing action through the PLC controller until the specified tilt angle is reached and then stop.

[0024] S2-2. Adjust the lubricating oil circuit by switching the on / off state of each oil outlet of each single-way solenoid valve and multi-way solenoid valve group. After adjustment, start the lubricating oil pump station to supply oil for unblocking.

[0025] S2-3. Check the flow rate using a flow meter to determine if it is normal and assess the patency of the return oil pipe.

[0026] As a further preferred technical solution, in steps S2-3, when the flow rate of the flow meter continuously exceeds 10L / min for at least 3 seconds, it is determined that the flow rate at the current flow meter is normal and the current return oil pipe is successfully unblocked.

[0027] As a further preferred technical solution, in step S2, when 10° < tilt angle ≤ 20° or tilt angle > 20°, the specific steps of the unblocking operation of the return oil pipe further include: S2-4, by comparing the flow value of the flow meter at the current return oil pipe with the flow value of the flow meter at the other return oil pipe, it is determined whether the other return oil pipe located at the lower position of the current return oil pipe is blocked during the unblocking operation in step S2-2; if a blockage occurs, the other return oil pipe is unblocked.

[0028] Further, the specific steps of steps S2-4 include: first reading the flow value of the flow meter at the current return oil pipe and the flow value of the flow meter at the other return oil pipe; if the flow value of the flow meter at the other return oil pipe is less than the flow value of the flow meter at the current return oil pipe * 50%, the PLC controller is used to control the unblocking operation of the other return oil pipe; if the flow value of the flow meter at the other return oil pipe is greater than the flow value of the flow meter at the current return oil pipe * 50%, the unblocking operation of the current return oil pipe is terminated.

[0029] As a preferred technical solution, in step S3, when the start enable signal of the luffing mechanism is detected to change from active to disconnected, the lubricating oil pump station is kept in the start state and continues to supply oil for a set time before the lubricating oil pump station is shut down.

[0030] As described above, the present invention has the following beneficial effects:

[0031] (1) The lubrication control system and control method of the crane luffing mechanism of the present invention can automatically start the lubricating oil pump when the luffing action is started, and automatically shut down the lubricating oil pump after the luffing is completed and the luffing mechanism stops; no manual operation of the lubrication system is required, preventing the operator from forgetting to start or shut down the lubricating oil pump.

[0032] (2) The lubrication control system and control method of the crane luffing mechanism of the present invention can achieve continuous oil supply during luffing action, reduce the start and stop frequency of the lubricating oil pump, and increase its service life.

[0033] (3) The lubrication control system and control method of the crane luffing mechanism of the present invention can automatically determine the smoothness of the oil circuit. After the blockage of the pipeline is detected, the pipeline is unblocked by performing luffing action and adjusting the lubricating oil circuit to achieve reverse flushing, thereby preventing the oil circuit blockage from causing excessive internal oil pressure and oil leakage. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the signal output points of the PLC controller in this invention.

[0035] Figure 2 This is the inverter terminal control circuit diagram in this invention.

[0036] Figure 3 This is the control circuit diagram of the lubricating oil pump in this invention.

[0037] Figure 4 This is a schematic diagram of the control system in this invention.

[0038] The specific reference numerals in the attached drawings are explained as follows: 1. Amplitude adjustment mechanism; 2. Oil inlet pipe; 3. First return oil pipe; 4. Second return oil pipe; 5. Third return oil pipe; 6. First solenoid valve; 7. Second solenoid valve; 8. Third solenoid valve; 9. Fourth solenoid valve; 10. First flow meter; 11. Second flow meter; 12. Third flow meter; 13. Tilt sensor; 14. Solenoid valve assembly; 15. Frequency converter; 16. PLC controller; 17. Remote control handle; 18. Lubricating oil pump station; 100. Drive motor; 101. Gearbox; 102. Drive component; 19. Amplification relay; 20. Decrease relay; 21. Amplification signal output point; 22. Decrease signal output point; 23. Start relay; 24. Lubricating oil pump station motor; 25. Delay control circuit; 26. Delay disconnect relay. Detailed Implementation

[0039] To better understand the purpose, structure, and function of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0040] In the description of this invention, it should be noted that the positional relationships indicated by terms such as "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" are based on the positional relationships shown in the accompanying drawings and are only for the purpose of facilitating the description of the embodiments of this invention and simplifying the description. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific direction, and therefore should not be construed as a limitation of this invention.

[0041] Example 1

[0042] like Figure 4As shown, this embodiment provides a lubrication control system for a crane luffing mechanism. The luffing mechanism 1 is connected to a lubricating oil pump station 18 via an oil inlet pipe 2 and an oil return pipe. The lubricating oil in the lubricating oil pump station 18 is transported to the gearbox 101 and drive component 102 of the luffing mechanism 1 via the oil inlet pipe 2, and then returns to the lubricating oil pump station 18 via the oil return pipe loop, forming an oil supply pipeline. The oil return pipe includes a first oil return pipe 3, a second oil return pipe 4, and a third oil return pipe 5. The inlets of the first oil return pipe 3, the second oil return pipe 4, and the third oil return pipe 5 are connected to the luffing mechanism 1 and are distributed sequentially from the near end to the far end of the luffing mechanism 1. The luffing mechanism 1 includes a drive motor 100, a gearbox 101, and a drive component 102. In this embodiment, the drive component 102 is a drive 100 nut.

[0043] The control system includes a flow meter, a single-channel solenoid valve, a multi-channel solenoid valve group 14, a tilt sensor 13, a PLC controller 16, a frequency converter 15, and a lubricating oil pump control circuit.

[0044] The flow meters are installed on each return oil pipe and are used to detect whether there is return oil in the oil circuit of the corresponding return oil pipe. The single-channel solenoid valves are installed on each return oil pipe and the inlet oil pipe 2. The single-channel solenoid valves are electrically connected to the PLC controller 16 and are controlled by the PLC controller 16 to open and close the oil circuit of their respective pipes. A first flow meter 10 and a first solenoid valve 6 are installed on the first return oil pipe 3; a second flow meter 11 and a second solenoid valve 7 are installed on the second return oil pipe 4; a third flow meter 12 and a third solenoid valve 8 are installed on the third return oil pipe 5; and a fourth solenoid valve 9 is installed on the inlet oil pipe 2. The fourth solenoid valve 9 is used to control the opening and closing of the oil circuit from the lubricating oil pump station 18 to the luffing mechanism 1. The multi-way solenoid valve assembly 14 adopts a one-inlet, three-outlet valve design. The oil inlet pipe 2 is connected to the first return oil pipe 3, the second return oil pipe 4, and the third return oil pipe 5 through the multi-way solenoid valve assembly 14. The multi-way solenoid valve assembly 14 includes an oil inlet, a first oil outlet, a second oil outlet, and a third oil outlet. The oil inlet of the multi-way solenoid valve assembly 14 is connected to the oil inlet pipe 2 and is located between the lubricating oil pump station 18 and the fourth solenoid valve 9. The three oil outlets of the multi-way solenoid valve assembly 14 are respectively connected to the first... The first return oil pipe 3, the second return oil pipe 4, and the third return oil pipe 5 are connected and located between the corresponding single-way solenoid valves and flow meters on each return oil pipe. The first oil outlet is connected to the oil line of the first return oil pipe 3, the second oil outlet is connected to the oil line of the second return oil pipe 4, and the third oil outlet is connected to the oil line of the third return oil pipe 5. The multi-way solenoid valve group 14 is electrically connected to the PLC controller 16 and is adjusted by the PLC controller 16 switching the on and off of the oil outlets to adjust the lubricating oil circuit.

[0045] The tilt sensor 13 is connected to the PLC controller 16 for measuring the angle between the luffing mechanism 1 and the horizontal plane. The frequency converter 15 is electrically connected to the drive motor 100 and the PLC controller 16. During operation, the PLC controller 16 acquires the tilt signal measured by the tilt sensor 13 in real time and processes the tilt signal into a control signal for output. The control signal includes an amplification enable signal and a reduction enable signal. The frequency converter 15 receives the control signal from the PLC controller 16 and controls the drive motor 100 to rotate forward or backward, thereby controlling the luffing mechanism 1 to perform amplification or reduction operations, realizing the luffing adjustment action of the luffing mechanism 1.

[0046] like Figures 1 to 3As shown, the lubricating oil pump control circuit includes a start relay 23 and a delay control circuit 25. The start relay 23 is connected in series with the delay control circuit 25. The delay control circuit 25 includes an amplification relay 19, a reduction relay 20, and a delay disconnection relay 26. The amplification relay 19 and the reduction relay 20 are connected in parallel and then connected in series with the delay disconnection relay 26. The PLC controller 16 has an amplification signal output point 21 and a reduction signal output point 22. The amplification signal output point 21 outputs an amplification enable signal to control the amplification relay 19 to switch on and off. The frequency converter 15 receives and responds to the amplification enable signal, thereby controlling the drive motor 100 of the luffing mechanism 1 to rotate forward, realizing the extension amplification action of the luffing mechanism 1. The reduction signal output point 22 outputs a reduction enable signal to control the reduction relay 20 to switch on and off. The frequency converter 15 receives and responds to the reduction enable signal, thereby controlling the drive motor 100 of the luffing mechanism 1 to rotate in reverse, realizing the retraction reduction action of the luffing mechanism 1. The control system also includes a remote control handle 17, which is located at the control console and is electrically connected to the PLC controller 16. The remote control handle 17 controls the start of the luffing mechanism 1 and controls the luffing action of the luffing mechanism 1 to change the tilt angle. During operation, the remote control handle 17 starts and controls the luffing mechanism 1 to perform luffing action, generating a start enable signal. During the luffing operation, the PLC controller 16 receives the start enable signal and automatically controls the lubricating oil pump station motor 24 to start synchronously, realizing the lubrication of the luffing mechanism 1. At the same time, during the lubrication process, the flow meter on the corresponding return oil line is used to automatically determine the blockage of the return oil line under different tilt angles. When the return oil line is determined to be blocked, the return oil line is cleared. In addition, during the lubrication process, the delay control circuit 25 in the system can realize the continuous lubrication of the luffing mechanism 1 by jogging, which can effectively reduce the number of start and stop of the lubricating oil pump station 18, ensure the continuous lubrication of the luffing mechanism 1 during operation, reduce the occurrence of oil overflow and leakage of the luffing mechanism 1, and further reduce the failure rate of the luffing mechanism 1.

[0047] Example 2

[0048] This embodiment provides a control method for a crane luffing mechanism lubrication control system based on Embodiment 1, including the following steps:

[0049] S1. The control system detects the enable signal to determine whether the amplitude transformer 1 is in the start state.

[0050] When the PLC controller 16 detects that the start enable signal of the luffing mechanism 1 is valid, it synchronously controls the start of the lubricating oil pump station motor 24 through the start relay 23. At this time, the lubricating oil is sent to the gearbox 101 and drive unit 102 of the luffing mechanism 1 through the oil inlet pipe 2 via the lubricating oil pump station 18, continuously providing lubrication for the luffing mechanism 1.

[0051] S2. During the operation of the luffing mechanism 1, the angle of inclination α is detected by the tilt sensor 13 to determine the return oil pipe to be inspected. The tilt angle α is the angle between the luffing mechanism 1 and the horizontal plane. Then, the return oil status in the return oil pipe to be inspected is detected by the flow meter. When there is no return oil in the return oil pipe, the current return oil pipe is cleared. When clearing different return oil pipes, the lubricating oil circuit is adjusted by switching the on and off of the solenoid valve.

[0052] (1) When the angle of inclination α is less than or equal to 10°, the third flow meter 12 is used to detect whether there is oil return in the third return pipe 5. Specifically, the flow value of the third flow meter 12 is monitored in real time. When the flow value of the third flow meter 12 is 0, it indicates that there is no oil return in the third return pipe 5, and it is determined that the third return pipe 5 is blocked. The third return pipe 5 is then cleared.

[0053] The unblocking operation of the third return oil pipe 5 includes the following specific steps:

[0054] S2-1. The luffing mechanism 1 is controlled by the PLC controller 16 to reduce its amplitude until the tilt angle sensor 13 detects that the tilt angle α of the luffing mechanism 1 is greater than 45°, at which point the luffing action automatically stops. During operation, when the luffing mechanism reduces its amplitude, the reduction relay 20 is energized, the start relay 23 remains energized and engaged, and the lubricating oil pump station 18 begins pumping oil.

[0055] S2-2. Adjust the lubricating oil circuit by switching the on and off of the solenoid valves: First, close the fourth solenoid valve 9 and the lubricating oil pump station 18, cutting off the oil circuit from the lubricating oil pump station 18 to the luffing mechanism 1; then, close the third solenoid valve 8, open the first solenoid valve 6 and the second solenoid valve 7, and at the same time, open the third oil outlet C of the solenoid valve group 14 and close the first oil outlet A and the second oil outlet B of the solenoid valve group 14; finally, start the lubricating oil pump station 18 and wait for the lubricating oil pump station 18 to continuously supply oil for 30 seconds.

[0056] S2-3. Check the flow rate with a flow meter to determine if the return oil pipe is clear. If the flow rate is normal, it means that the return oil pipe is clear. Specifically, if the flow rate of the third flow meter 12 exceeds 10L / min for at least 3 seconds, it can be determined that the flow rate at the third flow meter 12 is normal and the third return oil pipe 5 is clear.

[0057] (2) When the angle of 10° < inclination α ≤ 20°, the second flow meter 11 is used to detect whether there is oil return in the second return pipe 4. Specifically, the reading of the second flow meter 11 is monitored in real time. When the flow value of the second flow meter 11 = 0, it indicates that there is no oil return in the second return pipe 4, and it is determined that the second return pipe 4 is blocked. The second return pipe 4 is then cleared.

[0058] The unblocking operation of the second return oil pipe 4 includes the following specific steps:

[0059] S2-1. The luffing mechanism 1 is controlled by the PLC controller 16 to reduce its amplitude until the tilt sensor 13 detects that the tilt angle α of the luffing mechanism 1 is greater than 45°, at which point the luffing action automatically stops. During operation, when the luffing mechanism reduces its amplitude, the reduction relay 20 is energized, and the start relay 23 remains energized, causing the lubricating oil pump station 18 to start pumping oil. The purpose of this operation is to ensure that during the oil pumping process, after the lubricating oil enters the luffing mechanism 1 through the second return oil pipe 4, it flows directly to the first return oil pipe 3 under the action of gravity; this prevents lubricating oil containing impurities from flowing directly to the gearbox 101 and drive component 102 of the luffing mechanism 1, thus avoiding damage to the mechanical structure of the luffing mechanism 1.

[0060] S2-2. Adjust the lubricating oil circuit by switching the on and off of the solenoid valves: First, close the fourth solenoid valve 9 and the lubricating oil pump station 18, cutting off the lubricating oil circuit from the lubricating oil pump station 18 to the luffing mechanism 1; then, close the second solenoid valve 7, open the first solenoid valve 6, and at the same time, open the second oil outlet B of the solenoid valve group 14 and close the first oil outlet A and the third oil outlet C of the solenoid valve group 14; finally, start the lubricating oil pump station 18 and wait for the lubricating oil pump station 18 to continuously supply oil for 30 seconds.

[0061] S2-3. Check the flow rate with a flow meter to determine if the return oil pipe is clear. If the flow rate is normal, it means that the return oil pipe is clear. Specifically, if the flow rate of the second flow meter 11 exceeds 10L / min for at least 3 seconds, it can be determined that the flow rate at the second flow meter 11 is normal and the second return oil pipe 4 is clear.

[0062] S2-4. By comparing the flow rate of the first flow meter 10 and the flow rate of the second flow meter 11, determine whether the first return oil pipe 3 is blocked: Specifically, simultaneously read the flow rate of the first flow meter 10 and the flow rate of the second flow meter 11; if the flow rate of the first flow meter 10 is less than the flow rate of the second flow meter 11 * 50%, it indicates that impurities entered the first return oil pipe 3 during the process of clearing the second return oil pipe 4, causing partial blockage of the first return oil pipe 3, and the PLC controller 16 controls the clearing operation of the first return oil pipe 3; if the flow rate of the first flow meter 10 is greater than the flow rate of the second flow meter 11 * 50%, it indicates that the first return oil pipe 3 is not blocked, and the clearing operation of the second return oil pipe 4 ends.

[0063] (3) When the angle of inclination α is greater than 20°, the first flow meter 10 is used to detect whether there is oil return in the first return oil pipe 3. Specifically, the reading of the first flow meter 10 is monitored in real time. When the flow value of the first flow meter 10 is 0, it indicates that there is no oil return in the first return oil pipe 3, and it is determined that the first return oil pipe 3 is blocked. The first return oil pipe 3 is then cleared.

[0064] The unblocking operation of the first return oil pipe 3 includes the following specific steps:

[0065] S2-1. The luffing mechanism 1 is controlled by the PLC controller 16 to extend and increase its amplitude until the tilt sensor 13 detects that the tilt angle α of the luffing mechanism 1 is less than 10°, at which point the luffing action automatically stops. During operation, when the luffing mechanism is increasing its amplitude, the amplitude relay 19 is energized, the start relay 23 remains energized and engaged, and the lubricating oil pump station 18 begins pumping oil.

[0066] S2-2. Adjust the lubricating oil circuit by switching the on and off of the solenoid valves: First, close the fourth solenoid valve 9 and the lubricating oil pump station 18, cutting off the lubricating oil circuit from the lubricating oil pump station 18 to the luffing mechanism 1; then, close the first solenoid valve 6 and open the second solenoid valve 7. At the same time, open the first oil outlet A of the solenoid valve group 14 and close the second oil outlet B and the third oil outlet C of the solenoid valve group 14; finally, start the lubricating oil pump station 18 and wait for the lubricating oil pump station 18 to continuously supply oil for 30 seconds.

[0067] S2-3. Check the flow rate with a flow meter to determine if the return oil pipe is clear. If the flow rate is normal, it means that the return oil pipe is clear. Specifically, if the flow rate of the third flow meter 12 exceeds 10L / min for at least 3 seconds, it can be determined that the flow rate at the third flow meter 12 is normal and the third return oil pipe 5 is clear.

[0068] S2-4. By comparing the flow rate of the first flow meter 10 and the flow rate of the second flow meter 11, determine whether the second return oil pipe 4 is blocked: Specifically, simultaneously read the flow rate of the first flow meter 10 and the flow rate of the second flow meter 11; if the flow rate of the second flow meter 11 is less than 50% of the flow rate of the first flow meter 10, it indicates that impurities entered the second return oil pipe 4 during the process of clearing the first return oil pipe 3, causing partial blockage of the second return oil pipe 4, and the PLC controller 16 controls the clearing operation of the second return oil pipe 4; if the flow rate of the second flow meter 11 is greater than 50% of the flow rate of the first flow meter 10, it indicates that the second return oil pipe 4 is not blocked, and the clearing operation of the first return oil pipe 3 ends.

[0069] S3. The control system detects the enable signal to determine whether the luffing mechanism 1 is still in the start state. When the luffing mechanism 1 changes from start to stop, the lubricating oil pump station 18 is shut down after a delay. When the PLC controller 16 detects that the start enable signal of the luffing mechanism 1 changes from active to off, the lubricating oil pump station 18 is kept in the start state and continues to supply oil for 10 seconds. Figure 4 As shown, after 10 seconds of oil supply, the lubricating oil pump station 18 is shut off using the delay control circuit 25 in the dotted section; the delay of the delay disconnect relay 26 is set to 10 seconds, that is, when the amplitude change stops, the lubricating oil pump station 18 is controlled to continue pumping oil for 10 seconds.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art can make various changes or equivalent substitutions to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this invention.

Claims

1. A lubrication control method for a crane luffing mechanism, characterized in that, Includes the following steps: S1. Determine whether the luffing mechanism (1) is in the starting state: When it is in the starting state, start the lubricating oil pump station (18) simultaneously to provide lubrication for the luffing mechanism (1); S2. During the operation of the luffing mechanism (1), the tilt angle is detected by the tilt sensor (13) and the return oil pipe to be inspected is determined. The tilt angle is the angle between the luffing mechanism (1) and the horizontal plane. Then, the return oil condition in the return oil pipe is detected by the flow meter. When there is no return oil in the return oil pipe, the return oil pipe is cleared. When clearing different return oil pipes, the lubricating oil circuit is adjusted by switching the on / off state of each oil outlet of each single solenoid valve and multi-way solenoid valve group (14). S3. Determine whether the luffing mechanism (1) is still in the starting state. When the luffing mechanism (1) changes from starting to closing, delay shutting down the lubricating oil pump station (18); where, In step S2, the specific steps of detecting the tilt angle and determining the return oil pipe to be inspected by the tilt sensor (13) include: When the tilt angle is ≤10°, check whether there is return oil in the third return oil pipe (5); When 10° < tilt angle ≤ 20°, check whether there is return oil in the second return oil pipe (4); When the tilt angle is greater than 20°, check whether there is return oil in the first return oil pipe (3); Furthermore, in step S2, the specific steps for unblocking the return oil pipe include: S2-1. Control the luffing mechanism (1) to perform luffing action through the PLC controller (16) until the specified tilt angle is reached and then stop. S2-2. Adjust the lubricating oil circuit by switching the on / off state of each oil outlet of each single-way solenoid valve and multi-way solenoid valve group (14). After the adjustment is completed, start the lubricating oil pump station (18) to supply oil for unblocking. S2-3. Check the flow rate using a flow meter to determine if it is normal and assess the patency of the return oil pipe.

2. The lubrication control method for a crane luffing mechanism according to claim 1, characterized in that, In step S2, the specific steps for detecting the return oil status in the return oil pipe by means of a flow meter, and performing the unblocking operation of the return oil pipe when there is no return oil in the return oil pipe include: real-time monitoring of the flow value of the flow meter; when the flow value of the flow meter = 0, it indicates that there is no return oil in the return oil pipe where the flow meter is located, and it is determined that the current return oil pipe is blocked, and the unblocking operation of the current return oil pipe is performed.

3. The lubrication control method for a crane luffing mechanism according to claim 1, characterized in that, In steps S2-3, when the flow rate of the flow meter exceeds 10 L / min for at least 3 seconds, it is determined that the flow rate at the current flow meter is normal and the current return oil pipe is successfully unblocked.

4. The lubrication control method for a crane luffing mechanism according to claim 1, characterized in that, In step S2, when 10° < tilt angle ≤ 20° or tilt angle > 20°, the specific steps of the unblocking operation of the return oil pipe also include: S2-4, by comparing the flow value of the flow meter at the current return oil pipe with the flow value of the flow meter at the other return oil pipe, it is determined whether the other return oil pipe located at the lower position of the current return oil pipe is blocked during the unblocking operation in step S2-2; if a blockage occurs, the other return oil pipe is unblocked.

5. The lubrication control method for a crane luffing mechanism according to claim 4, characterized in that, The specific steps of step S2-4 include: first reading the flow value of the flow meter at the current return oil pipe and the flow value of the flow meter at the other return oil pipe; if the flow value of the flow meter at the other return oil pipe is less than the flow value of the flow meter at the current return oil pipe * 50%, the other return oil pipe is cleared by controlling the PLC controller (16); if the flow value of the flow meter at the other return oil pipe is greater than the flow value of the flow meter at the current return oil pipe * 50%, the clearing operation of the current return oil pipe is ended.

6. The lubrication control method for a crane luffing mechanism according to claim 1, characterized in that, In step S3, when the start enable signal of the variable amplitude mechanism (1) is detected to change from active to disconnected, the lubricating oil pump station (18) is kept in the start state and continues to supply oil for a set time, and then the lubricating oil pump station (18) is shut down.

7. A lubrication control system for a crane luffing mechanism, used in the lubrication control method for a crane luffing mechanism as described in any one of claims 1-6, characterized in that... The luffing mechanism (1) is connected to a lubricating oil pump station (18) via an oil inlet pipe (2) and a return oil pipe. The lubricating oil in the lubricating oil pump station (18) is transported to the gearbox (101) and drive unit (102) of the luffing mechanism (1) via the oil inlet pipe (2), and returns to the lubricating oil pump station (18) via the return oil pipe loop, forming an oil delivery pipeline. The return oil pipe includes a first return oil pipe (3), a second return oil pipe (4), and a third return oil pipe (5). The first return oil pipe (3), the second return oil pipe (4), and the third return oil pipe (5) are connected to the lubricating oil pump station (18) via the oil inlet pipe (2). The inlets of pipe (4) and the third return oil pipe (5) are connected to the luffing mechanism (1) and are distributed sequentially from the near end to the far end of the luffing mechanism (1). The luffing mechanism (1) includes a drive motor (100), a gearbox (101) and a drive component (102). The lubrication control system includes a flow meter, a single-way solenoid valve, a multi-way solenoid valve group (14), an inclination sensor (13), a PLC controller (16), a frequency converter (15) and a lubricating oil pump control circuit. The flow meter is installed on each return oil pipe; the single-channel solenoid valve is installed on each return oil pipe and the inlet oil pipe (2). The single-channel solenoid valve is electrically connected to the PLC controller (16) and is controlled by the PLC controller (16) to open and close the oil circuit in the pipeline. The multi-way solenoid valve group (14) adopts a one-in-three-out valve. The oil inlet pipe (2) is connected to each return oil pipe through the multi-way solenoid valve group (14). The oil inlet of the multi-way solenoid valve group (14) is connected to the oil inlet pipe (2) and is located between the lubricating oil pump station (18) and the single-way solenoid valve at the oil inlet pipe (2). The three oil outlets of the multi-way solenoid valve group (14) are respectively connected to each return oil pipe and are located between the corresponding single-way solenoid valve and flow meter on each return oil pipe. The multi-way solenoid valve group (14) is electrically connected to the PLC controller (16) and is adjusted by the PLC controller (16) switching the on and off of the oil outlets to adjust the lubricating oil circuit. The tilt sensor (13) is connected to the PLC controller (16) via signal. The frequency converter (15) is electrically connected to the drive motor (100) and the PLC controller (16) respectively. The PLC controller (16) collects the tilt signal measured by the tilt sensor (13) in real time and processes the tilt signal into a control signal for output. The frequency converter (15) receives the control signal sent by the PLC controller (16) and controls the drive motor (100) to rotate forward or reverse, so that the amplitude mechanism (1) can perform amplitude increase or decrease operations. The lubricating oil pump control circuit includes a start relay (23) and a delay control circuit (25) connected in series. The delay control circuit (25) includes an amplification relay (19), a reduction relay (20), and a delay disconnect relay (26). The amplification relay (19) and the reduction relay (20) are connected in parallel and then connected in series with the delay disconnect relay (26).

8. A lubrication control system for a crane luffing mechanism according to claim 7, characterized in that, The control system also includes a remote control handle (17), which is electrically connected to the PLC controller (16). The remote control handle (17) controls the start of the luffing mechanism (1) and controls the luffing mechanism (1) to perform luffing actions to change the angle of the tilt.

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