Lubrication control system for luffing mechanism of crane and control method of lubrication control system

Abstract

The invention discloses a crane luffing mechanism lubrication control system and a control method thereof, the control system is arranged on the basis of a conventional crane luffing mechanism and a lubricating oil pump station, and the control system comprises a flowmeter, a one-way electromagnetic valve, a multi-way electromagnetic valve group, a tilt angle sensor, a PLC (Programmable Logic Controller), a frequency converter and a lubricating oil pump control circuit, a remote control handle is further included. According to the control method, in the luffing operation process, a lubricating oil pump station is automatically controlled to be started through a control system, and synchronous lubricating and oiling of a luffing mechanism are achieved; in the lubricating and oiling process, under the condition of different inclination angles, the flow meters on the corresponding oil return pipelines are used for automatically judging the blockage condition of the oil return pipelines, and dredging is conducted when blockage occurs; in the lubricating process, inching of the luffing mechanism is achieved through the delay control circuit, oil is not cut off, the starting and stopping frequency of a lubricating oil pump station is effectively reduced, continuous lubrication in the running process of the luffing mechanism is ensured, the oil spilling and leaking conditions are reduced, and the fault rate of the luffing mechanism is further reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of cranes, and in particular relates to a lubrication control system for a crane luffing mechanism and a control method thereof. Background Art

[0002] Portal cranes are widely used in shipbuilding and port loading and unloading, and the luffing mechanism is its main moving mechanism. The conventional lubrication system currently uses manual control and cannot form an effective linkage with the luffing action. After long-term operation, there will be problems such as oil leakage and blockage, and it cannot form an effective lubrication effect. During high-frequency lifting, due to lack of lubrication, the transmission parts are severely worn and the heat dissipation is poor, shortening the service life of the luffing mechanism. In addition, since the main force-bearing parts of the luffing mechanism are enclosed in the telescopic sleeve, they cannot be visually inspected in time, posing a greater safety risk.

[0003] Therefore, it is considered to develop an effective crane luffing mechanism lubrication control system and its control method using a PLC controller combined with an inclination sensor.

[0004] After searching, the Chinese invention document with the existing announcement number CN103629175B discloses a working bucket hydraulic control system and an engineering vehicle. "The present invention discloses a working bucket hydraulic control system and an engineering vehicle. The control system includes a leveling cylinder and a leveling control circuit, a boom cylinder and a boom control circuit, and a boosting cylinder and a boosting oil circuit. The rod chamber oil circuit of the boosting cylinder is connected to the main oil inlet oil circuit; the boosting oil circuit is provided with a first switch control valve and has a first bypass oil circuit hydraulically connected to the rod chamber of the boom cylinder and a second bypass oil circuit hydraulically connected to the system oil tank and provided with a second switch control valve." Although an inclination sensor is also used in the invention, the inclination angle in the invention is only used as a condition for controlling the electric proportional control valve to adjust the hydraulic oil flow to the leveling cylinder, which has certain limitations. Summary of the invention

[0005] In order to solve the problems existing in the prior art mentioned above, the purpose of the present invention is to provide a crane luffing mechanism lubrication control system and a control method thereof, which can automatically start lubrication and oiling during the luffing action, form a synchronous linkage with the luffing mechanism, achieve effective lubrication, and enhance the heat dissipation of the transmission mechanism through lubricating oil, thereby further reducing the wear of the mechanism; the system has an automatic start and stop function, so the method is highly safe, effectively reduces crane downtime, and saves costs.

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

[0007] A first aspect of the present invention provides a lubrication control system for a crane luffing mechanism, wherein the luffing mechanism is connected to a lubricating oil pump station through an oil inlet pipe and an oil return pipe, the lubricating oil in the lubricating oil pump station is transported to a gear box and a driving member of the luffing mechanism through the oil inlet pipe, and returns to the lubricating oil pump station through an oil return pipe loop to form an oil delivery pipeline, the oil return pipe comprises 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 sequentially distributed from the proximal end to the distal end of the luffing mechanism, the luffing mechanism comprises a drive motor, a gear box and a driving member, and the lubrication control system comprises a flow meter, a single-way solenoid valve, a multi-way solenoid valve group, an inclination sensor, a PLC controller, a frequency converter and a lubricating oil pump control circuit;

[0008] The flow meter is arranged on each oil return pipe; the one-way solenoid valve is arranged on each oil return pipe and oil inlet pipe, the one-way solenoid valve is electrically connected to the PLC controller, and the on-off of the oil circuit of the pipeline is controlled by the PLC controller;

[0009] The multi-way solenoid valve group adopts a one-inlet and three-outlet 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 the PLC controller switches the oil outlet on and off to adjust the circuit of the lubricating oil;

[0010] The inclination sensor is connected to the PLC controller by signal, the frequency converter is electrically connected to the drive motor and the PLC controller respectively, the PLC controller collects the inclination signal measured by the inclination sensor in real time and processes the inclination 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 variation mechanism performs an amplitude increase or amplitude decrease operation;

[0011] The lubricating oil pump control circuit includes a starting relay and a delay control circuit connected in series. The delay control circuit includes an amplifying relay, a reducing relay and a delayed disconnecting relay. The amplifying relay and the reducing relay are connected in parallel and then connected in series with the delayed disconnecting relay.

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

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

[0014] S1. Determine whether the luffing mechanism is in the starting state: when in the starting state, start the lubricating oil pump station synchronously to provide lubrication for the luffing mechanism;

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

[0016] S3. Determine whether the luffing mechanism is still in the start-up state. When the luffing mechanism changes from start to close, delay the closure of the lubricating oil pump station.

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

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

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

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

[0021] As a preferred technical solution, in step S2, the return oil situation in the return oil pipe is detected by a flow meter. When there is no return oil in the return oil pipe, the specific steps of unclogging 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 is prompted 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 current return oil pipe is unclogging.

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

[0023] S2-1, control the luffing mechanism through the PLC controller to perform the luffing action until the specified inclination angle is reached and stops;

[0024] S2-2, adjust the lubricating oil circuit by switching on and off each oil outlet of each single-way solenoid valve and multi-way solenoid valve group. After the adjustment is completed, start the lubricating oil pump station to supply oil for dredging;

[0025] S2-3. Use the flow meter to check whether the flow is normal and determine whether the return oil pipe is unobstructed.

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

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

[0028] Furthermore, the specific steps of step S2-4 include: first reading the flow value of the flow meter at the current oil return pipe and the flow value of the flow meter at another oil return pipe; if the flow value of the flow meter at the other oil return pipe is < the flow value of the flow meter at the current oil return pipe * 50%, the unblocking operation of the other oil return pipe is controlled by the PLC controller; if the flow value of the flow meter at the other oil return pipe is > the flow value of the flow meter at the current oil return pipe * 50%, the unblocking operation of the current oil return pipe is ended.

[0029] As a preferred technical solution, in step S3, when it is detected that the start-up enable signal of the amplitude varying mechanism changes from valid to disconnected, the lubricating oil pump station is kept started and continues to supply oil for a set time, and then the lubricating oil pump station is shut down.

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

[0031] (1) A crane luffing mechanism lubrication control system and control method of the present invention can automatically start the lubricating oil pump when the luffing action is started, and automatically turn off the lubricating oil pump after the luffing is completed and the luffing mechanism stops. There is no need to manually operate the lubrication system, which prevents the operator from forgetting to start or turn off the lubricating oil pump.

[0032] (2) A crane luffing mechanism lubrication control system and control method 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) A crane luffing mechanism lubrication control system and control method of the present invention can automatically determine the patency of the oil circuit. After identifying that the pipeline is blocked, the pipeline is unblocked by performing luffing action and adjusting the lubricating oil circuit for reverse flushing, thereby preventing the internal oil pressure from being too high due to oil circuit blockage and oil leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the signal output position of the PLC controller in the present invention.

[0035] Figure 2 This is the inverter end control circuit diagram of the present invention.

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

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

[0038] Among them, the specific descriptions of the accompanying drawings are as follows: 1. variable amplitude mechanism; 2. oil inlet pipe; 3. first oil return pipe; 4. second oil return pipe; 5. third oil return 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. inclination sensor; 14. solenoid valve group; 15. frequency converter; 16. PLC controller; 17. remote control handle; 18. lubricating oil pump station; 100. drive motor; 101. gear box; 102. drive element; 19. amplifier relay; 20. reduction relay; 21. amplifier signal output position; 22. reduction signal output position; 23. start relay; 24. lubricating oil pump station motor; 25. delay control circuit; 26. delay disconnect relay. DETAILED DESCRIPTION

[0039] In order to better understand the purpose, structure and function of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0040] In the description of the present 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”, “inside” and “outside” etc. cited in this specification are based on the positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0041] Example 1

[0042] like Figure 4As shown, this embodiment provides a lubrication control system for a crane luffing mechanism, wherein the luffing mechanism 1 is connected to a lubricating oil pump station 18 through an oil inlet pipe 2 and an oil return pipe, and the lubricating oil in the lubricating oil pump station 18 is transported to the gear box 101 and the driving member 102 of the luffing mechanism 1 through the oil inlet pipe 2, and returns to the lubricating oil pump station 18 through the oil return pipe loop to form an oil delivery pipeline, the oil return pipe comprises 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 in sequence from the proximal end to the distal end of the luffing mechanism 1, the luffing mechanism 1 comprises a driving motor 100, a gear box 101 and a driving member 102, and in this embodiment, the driving member 102 adopts a driving nut 100.

[0043] The 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.

[0044] The flowmeter is arranged on each oil return pipe, and the flowmeter is used to detect whether there is return oil in the oil circuit of the oil return pipe. The single-way solenoid valve is arranged on each oil return pipe and the oil inlet pipe 2, and the single-way solenoid valve is electrically connected to the PLC controller 16, and the on-off of the oil circuit of the pipeline is controlled by the PLC controller 16. The first oil return pipe 3 is provided with a first flowmeter 10 and a first solenoid valve 6, the second oil return pipe 4 is provided with a second flowmeter 11 and a second solenoid valve 7, and the third oil return pipe 5 is provided with a third flowmeter 12 and a third solenoid valve 8; the oil inlet pipe 2 is provided with a fourth solenoid valve 9, and the fourth solenoid valve 9 is used to control the on-off of the oil circuit from the lubricating oil pump station 18 to the amplitude change mechanism 1. The multi-way solenoid valve group 14 adopts a one-inlet and three-outlet valve. The oil inlet pipe 2 is connected to the first oil return pipe 3, the second oil return pipe 4, and the third oil return pipe 5 through the multi-way solenoid valve group 14. The multi-way solenoid valve group 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 group 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 group 14 are respectively connected to the first oil return pipe 3, the second oil return pipe 4, and the third oil return pipe 5. The first oil return pipe 3, the second oil return pipe 4, and the third oil return pipe 5 are connected and are located between the corresponding single-way solenoid valves and flow meters on each oil return pipe. The first oil outlet is connected to the oil circuit of the first oil return pipe 3, the second oil outlet is connected to the oil circuit of the second oil return pipe 4, and the third oil outlet is connected to the oil circuit of the third oil return pipe 5. The multi-way solenoid valve group 14 is electrically connected to the PLC controller 16, and the PLC controller 16 switches the oil outlet on and off to adjust the circuit of the lubricating oil.

[0045] The inclination sensor 13 is signal-connected to the PLC controller 16 for measuring the angle of the amplitude varying mechanism 1 relative to the horizontal plane. The frequency converter 15 is electrically connected to the drive motor 100 and the PLC controller 16, respectively. During operation, the PLC controller 16 collects the inclination signal measured by the inclination sensor 13 in real time and processes the inclination signal into a control signal output. The control signal includes an amplification enable signal and a reduction enable signal. 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 as to control the amplitude varying mechanism 1 to perform an amplification or reduction operation, thereby realizing the amplitude varying adjustment action of the amplitude varying mechanism 1.

[0046] like Figures 1 to 3As shown, the lubricating oil pump control circuit includes a starting relay 23 and a delay control circuit 25. The starting relay 23 is connected in series to the delay control circuit 25. The delay control circuit 25 includes an amplifying relay 19, a reducing relay 20 and a delayed disconnecting relay 26. The amplifying relay 19 and the reducing relay 20 are connected in parallel and then connected in series with the delayed disconnecting relay 26. The PLC controller 16 is provided with an amplification signal output position 21 and a reduction signal output position 22; the amplification signal output position 21 outputs an amplification enable signal to control the switch of the amplification relay 19 to be closed, and the frequency converter 15 receives and responds to the amplification enable signal, thereby controlling the drive motor 100 of the amplitude variable mechanism 1 to rotate forward, thereby realizing the extension amplification action of the amplitude variable mechanism 1; the reduction signal output position 22 outputs a reduction enable signal to control the switch of the reduction relay 20 to be closed, and the frequency converter 15 receives and responds to the reduction enable signal, thereby controlling the drive motor 100 of the amplitude variable mechanism 1 to rotate reversely, thereby realizing the retracting and reduction action of the amplitude variable 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 amplitude variable mechanism 1 to start and controls the amplitude variable mechanism 1 to perform the amplitude change action to change the angle of the inclination. During operation, the remote control handle 17 starts and controls the amplitude variation mechanism 1 to perform the amplitude variation action, and generates a start enable signal. During the amplitude variation operation, the PLC controller 16 automatically controls the lubricating oil pump station motor 24 to start synchronously after receiving the start enable signal, so as to realize the lubrication and refueling of the amplitude variation mechanism 1. At the same time, during the lubrication and refueling process, the flow meter on the corresponding return oil pipeline is used to automatically judge the blockage of the return oil pipeline under different inclination angles. When it is judged that the return oil pipeline is blocked, the return oil pipeline is cleared, and during the lubrication process, the delay control circuit 25 in the system can realize the continuous oil supply of the amplitude variation mechanism 1, which can effectively reduce the start and stop times of the lubricating oil pump station 18, ensure the continuous lubrication of the amplitude variation mechanism 1 during operation, reduce the occurrence of oil overflow and oil leakage of the amplitude variation mechanism 1, and further reduce the failure rate of the amplitude variation mechanism 1.

[0047] Example 2

[0048] This embodiment provides a control method of a crane luffing mechanism lubrication control system using the embodiment 1, comprising the following steps:

[0049] S1. Determine whether the luffing mechanism 1 is in the starting state by detecting the enabling signal through the control system.

[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 gear box 101 and the driving part 102 of the luffing mechanism 1 through the lubricating oil pump station 18 through the oil inlet pipe 2, continuously providing lubrication for the luffing mechanism 1.

[0051] S2. During the operation of the variable-length mechanism 1, the inclination angle α is detected by the inclination sensor 13 and the return oil pipe to be inspected is determined. The inclination angle α is the angle between the variable-length mechanism 1 and the horizontal plane. Then, the return oil condition 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 unblocked. When unblocking different return oil pipes, the lubricating oil circuit is adjusted by switching the on and off of the solenoid valve.

[0052] (1) When the inclination angle α is ≤10°, the third flow meter 12 is used to detect whether there is return oil in the third oil 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 = 0, it is indicated that there is no return oil in the third oil return pipe 5, and it is determined that the third oil return pipe 5 is blocked, and the third oil return pipe 5 is unblocked.

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

[0054] S2-1, the PLC controller 16 controls the luffing mechanism 1 to close and reduce the amplitude until the inclination sensor 13 detects that the inclination angle α of the luffing mechanism 1 is greater than 45°, and the luffing action is automatically stopped. During operation, when the luffing mechanism performs the reduction action, the reduction relay 20 is energized, the start relay 23 remains energized and energized, and the lubricating oil pump station 18 starts 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 to cut off the oil path of the lubricating oil from the lubricating oil pump station 18 to the boom 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. Use a flow meter to detect whether the flow is normal to determine whether the return oil pipe is unblocked successfully. If the flow is normal, it indicates that the current return oil pipe has been unblocked: specifically, when the flow value of the third flow meter 12 exceeds 10L / min for at least 3 seconds, it can be determined that the flow at the third flow meter 12 is normal and the third return oil pipe 5 is unblocked successfully.

[0057] (2) When the angle of inclination α is 10°≤20°, the second flow meter 11 is used to detect whether there is return oil in the second oil 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 is 0, it is indicated that there is no return oil in the second oil return pipe 4, and it is determined that the second oil return pipe 4 is blocked, and the second oil return pipe 4 is cleared.

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

[0059] S2-1, control the luffing mechanism 1 to close and reduce the amplitude through the PLC controller 16, until the inclination sensor 13 detects that the inclination angle α of the luffing mechanism 1 is greater than 45°, and then automatically stops the luffing action. During operation, when the luffing is reducing the amplitude, the amplitude reduction relay 20 is energized, the start relay 23 remains energized and energized, and the lubricating oil pump station 18 starts pumping oil. The purpose of this operation is to allow the lubricating oil to enter the luffing mechanism 1 through the second oil return pipe 4 during the oil dredging process, and then flow directly to the first oil return pipe 3 under the action of gravity; it can prevent the lubricating oil containing impurities from flowing directly to the gear box 101 and the drive member 102 of the luffing mechanism 1, thereby 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 to cut off the oil path from the lubricating oil pump station 18 to the boom mechanism 1; then, close the second solenoid valve 7 and open the first solenoid valve 6. 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. Use the flow meter to detect whether the flow rate is normal to determine whether the return oil pipe is unblocked successfully. If the flow rate is normal, it indicates that the current return oil pipe has been unblocked: specifically, when the flow value 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 unblocked successfully.

[0062] S2-4. Determine whether the first oil return pipe 3 is blocked by comparing the flow value of the first flow meter 10 with the flow value of the second flow meter 11: specifically, read the flow value of the first flow meter 10 and the flow value of the second flow meter 11 at the same time; if the flow value of the first flow meter 10 is less than the flow value of the second flow meter 11*50%, it means that in the process of unblocking the second oil return pipe 4, impurities have entered the first oil return pipe 3, resulting in partial blockage of the first oil return pipe 3, and the unblocking operation of the first oil return pipe 3 is controlled by the PLC controller 16; if the flow value of the first flow meter 10 is greater than the flow value of the second flow meter 11*50%, it indicates that the first oil return pipe 3 is not blocked, and the unblocking operation of the second oil return pipe 4 is terminated.

[0063] (3) When the inclination angle α is greater than 20°, the first flow meter 10 is used to detect whether there is return oil in the first oil return 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 = 0, it is indicated that there is no return oil in the first oil return pipe 3, and it is determined that the first oil return pipe 3 is blocked. The first oil return pipe 3 is unblocked and the unblocking operation of the first oil return pipe 3 is performed.

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

[0065] S2-1, the PLC controller 16 controls the extension of the luffing mechanism 1 until the inclination sensor 13 detects that the inclination angle α of the luffing mechanism 1 is less than 10°, and the luffing action is automatically stopped. During operation, when the luffing mechanism performs an amplification action, the amplification relay 19 is energized, the start relay 23 remains energized, and the lubricating oil pump station 18 starts 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 to cut off the oil path of the lubricating oil from the lubricating oil pump station 18 to the boom 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. Use a flow meter to detect whether the flow is normal to determine whether the return oil pipe is unblocked successfully. If the flow is normal, it indicates that the current return oil pipe has been unblocked: specifically, when the flow value of the third flow meter 12 exceeds 10L / min for at least 3 seconds, it can be determined that the flow at the third flow meter 12 is normal and the third return oil pipe 5 is unblocked successfully.

[0068] S2-4. Determine whether the second oil return pipe 4 is blocked by comparing the flow value of the first flow meter 10 and the flow value of the second flow meter 11: specifically, read the flow value of the first flow meter 10 and the flow value of the second flow meter 11 at the same time; if the flow value of the second flow meter 11 is less than the flow value of the first flow meter 10*50%, it means that in the process of unblocking the first oil return pipe 3, impurities have entered the second oil return pipe 4, resulting in partial blockage of the second oil return pipe 4, and the unblocking operation of the second oil return pipe 4 is controlled by the PLC controller 16; if the flow value of the second flow meter 11 is greater than the flow value of the first flow meter 10*50%, it indicates that the second oil return pipe 4 is not blocked, and the unblocking operation of the first oil return pipe 3 is terminated.

[0069] S3. The control system detects the enable signal to determine whether the luffing mechanism 1 is still in the start-up state. When the luffing mechanism 1 changes from start to close, the lubricating oil pump station 18 is closed with a delay: When the PLC controller 16 detects that the start-up enable signal of the luffing mechanism 1 changes from valid to disconnected, the lubricating oil pump station 18 is kept in the start-up state and continues to supply oil for 10 seconds. Figure 4 As shown, after 10 seconds of oil supply, the delay control circuit 25 in the dotted part is used to shut down the lubricating oil pump station 18; the delay of the delayed disconnection 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 only a preferred embodiment of the present invention and is not intended to limit the present invention. It is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A lubrication control system for a crane luffing mechanism, wherein 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 a gear box (101) and a driving member (102) of the luffing mechanism (1) via the oil inlet pipe (2), and returns to the lubricating oil pump station (18) via the oil return pipe loop to form an oil delivery pipeline, the oil return pipe comprises 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 sequentially distributed from the proximal end to the distal end of the luffing mechanism (1), the luffing mechanism (1) comprises a drive motor (100), a gear box (101), and a driving member (102), characterized in that: The lubrication control system comprises 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 lubrication oil pump control circuit; The flow meter is arranged on each oil return pipe; the single-way solenoid valve is arranged on each oil return pipe and the oil inlet pipe (2); the single-way solenoid valve is electrically connected to the PLC controller (16), and the on-off of the oil circuit of the pipeline is controlled by the PLC controller (16); The multi-way solenoid valve group (14) adopts a one-inlet and three-outlet valve. The oil inlet pipe (2) is connected to each oil return 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 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 (14) is electrically connected to the PLC controller (16) and is controlled by the PLC controller (16) to switch the oil outlet on and off to adjust the circuit of the lubricating oil. The inclination sensor (13) is signal-connected to the PLC controller (16); the frequency converter (15) is electrically connected to the drive motor (100) and the PLC controller (16) respectively; the PLC controller (16) collects the inclination signal measured by the inclination sensor (13) in real time and processes the inclination 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 perform forward or reverse rotation, so that the amplitude variation mechanism (1) performs an amplitude increase or amplitude decrease operation; The lubricating oil pump control circuit comprises a starting relay (23) and a delay control circuit (25) connected in series, wherein the delay control circuit (25) comprises an amplifying relay (19), a reducing relay (20) and a delayed disconnecting relay (26), wherein the amplifying relay (19) and the reducing relay (20) are connected in parallel and then connected in series with the delayed disconnecting relay (26).

2. A crane luffing mechanism lubrication control system according to claim 1, characterized in that: The control system further comprises a remote control handle (17), wherein the remote control handle (17) is electrically connected to the PLC controller (16), and the remote control handle (17) is used to control the luffing mechanism (1) to start and control the luffing mechanism (1) to perform a luffing action to change the angle of the inclination.

3. A control method for a crane luffing mechanism lubrication control system according to any one of claims 1 or 2, characterized in that: The following steps are involved: S1, determining whether the luffing mechanism (1) is in the starting state: when in the starting state, synchronously starting the lubricating oil pump station (18) to provide lubrication for the luffing mechanism (1); S2. During the operation of the variable-length mechanism (1), the inclination angle is detected by the inclination sensor (13) and the oil return pipe to be inspected is determined. The inclination angle is the angle between the variable-length mechanism (1) and the horizontal plane. Then, the oil return condition in the oil return pipe is detected by the flow meter. When there is no oil return in the oil return pipe, the oil return pipe is unblocked. When unblocking different oil return pipes, the lubricating oil circuit is adjusted by switching the oil outlets of each single-way solenoid valve and the multi-way solenoid valve group (14) on and off. S3, judging whether the luffing mechanism (1) is still in the start-up state, and when the luffing mechanism (1) changes from the start-up state to the shutdown state, the lubricating oil pump station (18) is shut down with a time delay.

4. The control method of a crane luffing mechanism lubrication control system according to claim 3, characterized in that: In step S2, the specific steps of detecting the inclination angle by the inclination sensor (13) and determining the oil return pipe to be inspected include: When the inclination angle is ≤10°, detect whether there is return oil in the third oil return pipe (5); When the inclination angle is 10°<≤20°, detect whether there is return oil in the second oil return pipe (4); When the inclination angle is greater than 20°, it is detected whether there is return oil in the first oil return pipe (3).

5. A crane luffing mechanism lubrication control system and control method according to claim 4, characterized in that: In step S2, the return oil situation in the return oil pipe is detected by a flow meter. When there is no return oil in the return oil pipe, the specific steps of unclogging 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 is prompted 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 current return oil pipe is unclogging.

6. A crane luffing mechanism lubrication control system and control method according to claim 4, characterized in that: In step S2, the specific steps of the unblocking operation of the oil return pipe include: S2-1, controlling the luffing mechanism (1) through the PLC controller (16) to perform the luffing action until the designated inclination angle is reached and the action stops; S2-2, adjusting the lubricating oil circuit by switching the oil outlets of each single-way solenoid valve and the multi-way solenoid valve group (14) on and off, and after the adjustment is completed, starting the lubricating oil pump station (18) to supply oil for dredging; S2-3. Use the flow meter to check whether the flow is normal and determine whether the return oil pipe is unobstructed.

7. A crane luffing mechanism lubrication control system and control method according to claim 6, characterized in that: In step S2-3, when the flow value of the flow meter exceeds 10 L / min for at least 3 seconds, it is determined that the flow at the current flow meter is normal and the current oil return pipe is unblocked successfully.

8. A crane luffing mechanism lubrication control system and control method according to claim 6, characterized in that: In the step S2, when the inclination angle is 10°<the inclination angle ≤20° or the inclination angle is>20°, the specific steps of the unblocking operation of the oil return pipe also include: S2-4, by comparing the flow value of the flow meter at the current oil return pipe with the flow value of the flow meter at another oil return pipe, it is determined whether the other oil return pipe located at the lower position of the current oil return pipe is blocked during the unblocking operation in step S2-2; if blockage occurs, unblocking operation is performed on the other oil return pipe.

9. A crane luffing mechanism lubrication control system and control method according to claim 8, characterized in that: The specific steps of step S2-4 include: first reading the flow value of the flow meter at the current oil return pipe and the flow value of the flow meter at another oil return pipe; if the flow value of the flow meter at the other oil return pipe is less than the flow value of the flow meter at the current oil return pipe*50%, controlling the dredging operation of the other oil return pipe through the PLC controller (16); if the flow value of the flow meter at the other oil return pipe is greater than the flow value of the flow meter at the current oil return pipe*50%, ending the dredging operation of the current oil return pipe.

10. A crane luffing mechanism lubrication control system and control method thereof according to claim 3, characterized in that: In step S3, when it is detected that the start-up enable signal of the amplitude variable mechanism (1) changes from valid to disconnected, the lubricating oil pump station (18) is kept in the started state and continues to supply oil for a set time, and then the lubricating oil pump station (18) is shut down.

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