Synchronous hydraulic lifting system of unloading platform

Abstract

The invention relates to the technical field of synchronous hydraulic lifting, in particular to a synchronous hydraulic lifting system of an unloading platform, which is characterized in that a three-phase asynchronous motor is started to drive a gear hydraulic pump to operate, hydraulic oil enters a synchronous shunting motor after being preliminarily regulated and controlled by a control valve group, and the synchronous shunting motor distributes the hydraulic oil into two groups of lifting hydraulic cylinders at equal flow; during lifting of the lifting hydraulic cylinders, a stay wire displacement sensor and a tilt angle sensor are used for collecting displacement data of the two sets of lifting hydraulic cylinders in real time, electric signals are transmitted to a PLC, and the PLC compares signals of the two kinds of sensors and compares the signals with a preset displacement deviation threshold value for cross validation; the PLC controls the load-sensitive proportional valves to adjust the hydraulic oil pressure and flow of the corresponding hydraulic cylinders, so that the extension lengths of piston rods of the two sets of lifting hydraulic cylinders are consistent, and synchronous control over the lifting height of the unloading platform is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of synchronous hydraulic lifting, in particular to a synchronous hydraulic lifting system of a unloading platform. BACKGROUND

[0002] In logistics, warehousing and industrial unloading operations, the unloading platform is a commonly used device for efficient unloading and transfer of goods. Among them, the hydraulic lifting system is the core actuator of the unloading platform, and the lifting synchronization directly affects the stability, safety and efficiency of the unloading operation. The traditional hydraulic lifting system of the unloading platform often has the problem of lifting asynchronization due to uneven hydraulic circuit pressure and response differences of the execution element, which increases the risk of platform tilting and goods sliding, and also aggravates the mechanical wear of the equipment, shortens the service life, and cannot meet the needs of large-scale and high-precision unloading operations. Therefore, it is urgent to provide an unloading platform hydraulic lifting system that can accurately realize synchronous control of lifting height.

[0003] Therefore, in view of the deficiencies of the prior art, it is very necessary to provide an unloading platform synchronous hydraulic lifting system to solve the deficiencies of the prior art. SUMMARY

[0004] The purpose of the present application is to provide an unloading platform synchronous hydraulic lifting system to avoid the deficiencies of the prior art. The three-phase asynchronous motor starts to drive the gear hydraulic pump to operate. The hydraulic oil is preliminarily regulated by the control valve group, then enters the synchronous split-flow motor, and the synchronous split-flow motor distributes the hydraulic oil to two groups of lifting hydraulic cylinders at equal flow. The lifting hydraulic cylinders use the wire displacement sensor and the inclination sensor to collect the displacement data of the two groups of lifting hydraulic cylinders in real time and transmit the electrical signals to the PLC controller. The PLC controller compares the signals of the two types of sensors and cross-verifies them with the pre-set displacement deviation threshold module. If there is a deviation, the PLC controller controls the load-sensitive proportional valve to adjust the hydraulic oil pressure and flow of the corresponding hydraulic cylinder, so that the extension lengths of the piston rods of the two groups of lifting hydraulic cylinders are consistent, and the synchronous control of the lifting height of the unloading platform is realized.

[0005] The above-mentioned purpose of the present application is realized by the following technical means.

[0006] The present application provides an unloading platform synchronous hydraulic lifting system, which comprises an unloading platform, two groups of A-shaped beams installed at both ends of the unloading platform, a pump station installed on one side of the unloading platform, a hydraulic power mechanism provided on the unloading platform, a control valve group connected to the hydraulic power mechanism, a control unit provided in the pump station, a synchronous control mechanism and two groups of lifting hydraulic cylinders connected to the control unit, and the lifting hydraulic cylinders performing lifting operation on the unloading platform on the two groups of A-shaped beams. The synchronous control mechanism comprises a synchronous split-flow motor, a wire displacement sensor and a load-sensitive proportional valve, the synchronous split-flow motor has a plurality of oil outlets connected to the lifting hydraulic cylinder through high-pressure oil pipes, the wire displacement sensor is installed between the lifting hydraulic cylinder piston rod and the A-shaped beam, and the load-sensitive proportional valve is arranged on an oil circuit between the synchronous split-flow motor and the lifting hydraulic cylinder. The control unit is a PLC controller, which is electrically connected with the wire displacement sensor, the control valve group and the load-sensitive proportional valve, receives the displacement signal and adjusts the hydraulic oil parameters.

[0007] Preferably, the hydraulic power mechanism comprises a three-phase asynchronous motor, a gear hydraulic pump and an oil supply tank, the output shaft end of the three-phase asynchronous motor is rigidly connected with the input shaft of the hydraulic pump through a shaft coupling, and the oil supply tank is internally provided with an oil suction filter and an oil return filter.

[0008] Specifically, the control valve group comprises an electromagnetic reversing valve and an electrically-controlled overflow valve, the electromagnetic reversing valve is a three-position four-way type, and the electrically-controlled overflow valve is connected in series on the oil circuit.

[0009] Specifically, the PLC controller is internally provided with a data cross-verification module, a displacement deviation threshold module and a receiving module.

[0010] Specifically, the receiving module receives sensor signals, the data cross-verification module receives two types of sensor signals and performs cross-verification, the displacement deviation threshold module is self-defined, and the data cross-verification module controls the load-sensitive proportional valve by comparing the displacement deviation threshold module.

[0011] Preferably, the synchronous split-flow motor is a gear type split-flow motor, and the flow error of the hydraulic oil output by the oil outlet of the synchronous split-flow motor is not more than ±1 Specifically, the synchronous control mechanism further comprises an inclination sensor, the inclination sensor is installed at the geometric center of the unloading platform bearing surface, the inclination sensor and the wire displacement sensor jointly constitute a synchronous error detection unit, and the PLC controller receives two types of sensor signals and performs cross-verification.

[0012] Further, an operating handle is installed on the load-sensitive proportional valve, and the operating handle manually controls the load-sensitive proportional valve.

[0013] The application drives the gear hydraulic pump to run through the three-phase asynchronous motor, the hydraulic oil enters the synchronous split-flow motor after being preliminarily regulated through the control valve group, the synchronous split-flow motor distributes the hydraulic oil to two groups of lifting hydraulic cylinders at equal flow, the lifting hydraulic cylinder uses the wire displacement sensor and the inclination sensor to collect the displacement data of the two groups of lifting hydraulic cylinders in real time and transmits the electric signals to the PLC controller, the PLC controller compares the two types of sensor signals and compares and cross- verifies with the pre-set displacement deviation threshold value, if the deviation occurs, the PLC controller controls the load-sensitive proportional valve to adjust the hydraulic oil pressure and flow of the corresponding hydraulic cylinder, so that the piston rod extension lengths of the two groups of lifting hydraulic cylinders are consistent, and the synchronous control of the lifting height of the unloading platform is realized. BRIEF DESCRIPTION OF DRAWINGS

[0014] The application is further described by using the drawings, but the content in the drawings does not constitute any limitation on the application.

[0015] Fig. 1 It is the overall structure perspective view of the synchronous hydraulic lifting system of the unloading platform of the application.

[0016] Fig. 2 It is the hydraulic structure schematic view of the synchronous hydraulic lifting system of the unloading platform of the application.

[0017] Fig. 3 It is the structure schematic view of the internal module of the PLC controller in the synchronous hydraulic lifting system of the unloading platform of the application.

[0018] From Figs. 1-3 , including: 1. unloading platform; 2. A-shaped beam; 3. pump station; 4. lifting hydraulic cylinder; 5. synchronous split-flow motor; 6. load-sensitive proportional valve; 7. PLC controller; 8. three-phase asynchronous motor; 9. gear hydraulic pump; 10. oil supply tank; 11. electromagnetic reversing valve; 12. overflow valve; 13. data cross-verification module; 14. displacement deviation threshold value module; 15. receiving module; 16. inclination sensor; 17. wire displacement sensor. DETAILED DESCRIPTION

[0019] The application will be further described in conjunction with the following examples.

[0020] Example 1. As Figs. 1-3 shown, a synchronous hydraulic lifting system of a car unloading platform includes a car unloading platform 1, two groups of A-shaped beams 2 installed at both ends of the car unloading platform 1, a pump station 3 installed on one side of the car unloading platform 1, a hydraulic power mechanism arranged on the car unloading platform 1, the hydraulic power mechanism providing hydraulic power, a control valve group connected to the hydraulic power mechanism, a control unit arranged in the pump station 3, a synchronous control mechanism and two groups of lifting hydraulic cylinders 4 connected to the control unit, and the lifting hydraulic cylinders 4 lifting the car unloading platform 1 on the two groups of A-shaped beams 2.

[0021] The hydraulic power mechanism includes a three-phase asynchronous motor 8, a gear hydraulic pump 9, and an oil supply tank 10, the output shaft of the three-phase asynchronous motor 8 is rigidly connected to the input shaft of the hydraulic pump through a shaft coupling, and the oil supply tank 10 is internally provided with an oil suction filter and an oil return filter.

[0022] The hydraulic power unit serves as the power source of the entire system during the lifting of the car unloading platform 1, and is composed of the three-phase asynchronous motor 8, the gear hydraulic pump 9, and the oil supply tank 10. The motor is selected to be a three-phase asynchronous motor 8 with appropriate power, the output shaft of which is rigidly connected to the input shaft of the gear hydraulic pump 9 through a high-precision shaft coupling to ensure the efficiency and stability of power transmission. The gear hydraulic pump 9 has the advantages of compact structure, reliable operation, and good self-priming performance, and can stably extract hydraulic oil from the oil tank and output it after pressurization. The oil supply tank 10 is made of stainless steel and has good corrosion resistance. The oil supply tank 10 is internally provided with an oil suction filter and an oil return filter. The oil suction filter is installed at the bottom of the oil supply tank 10 and can effectively filter out large particles in the hydraulic oil to prevent them from entering the gear hydraulic pump 9 and causing wear to the gear hydraulic pump 9. The oil return filter is installed in the oil return pipeline and performs secondary filtration on the hydraulic oil returned to the oil supply tank 10 to ensure that the cleanliness of the hydraulic oil always meets the system operation requirements.

[0023] The control valve group is a key control component of the hydraulic power unit, which includes an electromagnetic reversing valve 11 and a relief valve 12. The electromagnetic reversing valve 11 is selected to be a three-position four-way type. By controlling the power-on and power-off of the electromagnetic coil, the flow direction of the hydraulic oil can be accurately changed to control the lifting, lowering, and stopping of the lifting hydraulic cylinders 4. The relief valve 12 is connected in series in the system oil circuit, and its set pressure value is adjusted according to the maximum working pressure of the system. When the system pressure exceeds the set value of the relief valve 12, the relief valve 12 opens to overflow the excess hydraulic oil back to the oil tank, thereby limiting the maximum working pressure of the system and preventing the system from being damaged due to excessive pressure.

[0024] The synchronous control mechanism comprises a synchronous split-flow motor 5, a wire displacement sensor 17 and a load-sensitive proportional valve 6, the synchronous split-flow motor 5 has multiple oil outlets connected to the lifting hydraulic cylinders 4 through high-pressure oil pipes, the wire displacement sensor 17 is installed between the piston rod of the lifting hydraulic cylinder 4 and the A-shaped beam 2, and the load-sensitive proportional valve 6 is arranged on the oil circuit between the synchronous split-flow motor 5 and the lifting hydraulic cylinder 4, and the synchronous control mechanism further comprises an inclination sensor 16 installed on the unloading platform 1.

[0025] The synchronous split-flow motor 5 adopts a high-precision gear structure, the gear engagement precision inside the synchronous split-flow motor 5 is strictly controlled, the flow error of each oil outlet can be stably controlled within ±1%, the oil inlet of the synchronous split-flow motor 5 is connected to the oil outlet of the gear hydraulic pump 9 through a high-pressure oil pipe, and the multiple oil outlets are respectively connected to the oil inlets of the lifting hydraulic cylinders 4 through high-pressure oil pipes, so that the hydraulic oil output by the gear hydraulic pump 9 can be uniformly distributed to each lifting hydraulic cylinder 4, thereby providing guarantee for realizing preliminary synchronous lifting.

[0026] The load-sensitive proportional valve 6 is arranged on the oil circuit between the synchronous split-flow motor 5 and the lifting hydraulic cylinder 4, and is a highly integrated hydraulic element with special pressure and flow regulation characteristics, the valve cooperates with the internal pressure compensator and flow control valve to realize real-time sensing of the change of the load pressure of the lifting hydraulic cylinder 4 and automatic adjustment of the flow passing through the valve according to the load demand, specifically, when the load borne by a certain lifting hydraulic cylinder 4 changes, the load-sensitive proportional valve 6 can quickly adjust the opening degree thereof, so that the hydraulic oil flow entering the hydraulic cylinder changes correspondingly, thereby ensuring that each lifting hydraulic cylinder 4 can still keep synchronous movement under different load conditions.

[0027] When the wire displacement sensor 17 is installed, the fixed end of the sensor is firmly installed at the bottom of the cylinder barrel of the lifting hydraulic cylinder 4, and the wire end is connected to the top end of the piston rod, the wire displacement sensor has the characteristics of high measurement precision and long measurement stroke, and the measurement stroke can completely cover the maximum lifting height range of the lifting hydraulic cylinder 4, in the lifting process, as the piston rod extends or retracts, the wire is pulled or loosened synchronously, the wire displacement sensor 17 can monitor the change of the extension length of the piston rod in real time and accurately through the internal precision measurement mechanism, and transmit the displacement signal to the PLC controller 7 in the form of an electric signal.

[0028] The newly added high-precision inclination sensor 16 is installed at the geometric center position of the bearing surface of the unloading platform 1, is used for detecting the inclination angle of the whole platform, and constitutes a synchronous error detection unit together with the wire displacement sensor, and the PLC controller 7 receives the signals of the two types of sensors and performs cross verification.

[0029] The control unit is a PLC controller 7, which is electrically connected with the stay cable displacement sensor, the control valve group and the load-sensitive proportional valve 6 respectively, receives the displacement signals and adjusts the parameters of the hydraulic oil.

[0030] The PLC controller 7 is internally provided with a data cross-verification module 13, a displacement deviation threshold module 14 and a receiving module 15.

[0031] The receiving module 15 receives the displacement sensor signals, the data cross-verification module 13 receives two types of sensor signals and performs cross-verification, the displacement deviation threshold module 14 is self-defined, and the data cross-verification module 13 compares the displacement deviation threshold module 14 to control the load-sensitive proportional valve 6.

[0032] The control unit adopts the PLC controller 7 as the core control element, which has powerful data processing capacity and logic control function. The PLC controller 7 is electrically connected with the stay cable displacement sensor 17, the inclination sensor 16, the electromagnetic reversing valve 11 in the control valve group and the control end of the load-sensitive proportional valve 6 through data lines and telecommunication methods respectively.

[0033] In the working process, the PLC controller 7 simultaneously receives the signals fed back by the stay cable displacement sensor 17 and the inclination sensor 16, establishes a “single-cylinder displacement deviation-platform inclination” double-threshold judgment model, firstly, the PLC controller 7 identifies the self-defined displacement deviation threshold, which is taken as the reference value of synchronous lifting; then, the actual displacement value of each hydraulic cylinder is compared with the displacement deviation threshold, and at the same time, the overall inclination angle of the platform detected by the inclination sensor 16 is combined, if it is found that the displacement deviation of a certain hydraulic cylinder exceeds the pre-set threshold, and the platform inclination angle is out of standard, the PLC controller 7 immediately sends corresponding control instructions to the electromagnetic reversing valve 11 in the control valve group and the load-sensitive proportional valve 6 according to the size and direction of the deviation.

[0034] For the electromagnetic reversing valve 11, by adjusting its power-on state, the flow direction of the hydraulic oil is changed to finely adjust the movement direction of the hydraulic cylinder; for the load-sensitive proportional valve 6, by changing the size of the control signal, the valve opening is accurately adjusted, and then the hydraulic oil flow and pressure entering the hydraulic cylinder are adjusted, so that the piston rod extension lengths of the lifting hydraulic cylinders 4 are quickly restored to be consistent, and high-precision synchronous lifting control is realized.

[0035] The load-sensitive proportional valve 6 can be connected with the PLC controller 7 to realize electric control, and at the same time, the operation handle installed on the load-sensitive proportional valve 6 can be manually controlled. The operation handle includes “lifting” and “oil supplementing”, the control unit automatically triggers the “oil supplementing” operation prompt, the operator switches the handle to the “oil supplementing” gear, the load-sensitive proportional valve 6 starts according to the above-mentioned “low-pressure oil supplementing” logic, and the control unit automatically triggers the “lifting” operation prompt in the same way as the automatic triggering of the “oil supplementing” operation.

[0036] The application drives the gear hydraulic pump 9 to run by the three-phase asynchronous motor 8. After the hydraulic oil is preliminarily regulated by the control valve group, the hydraulic oil is distributed to the two groups of lifting hydraulic cylinders 4 at the same flow rate by the synchronous split-flow motor 5. The lifting hydraulic cylinders 4 lift the middle part. The displacement data of the two groups of lifting hydraulic cylinders 4 are collected in real time by using the pull wire displacement sensor and the inclination sensor 16 and are transmitted to the PLC controller in the electrical signal. The PLC controller compares the two types of sensor signals and compares and cross- verifies with the pre-set displacement deviation threshold module 14. If there is a deviation, the PLC controller controls the load-sensitive proportional valve 6 to adjust the hydraulic oil pressure and flow rate of the corresponding hydraulic cylinder, so that the piston rod extension lengths of the two groups of lifting hydraulic cylinders 4 are consistent, and the synchronous control of the lifting height of the unloading platform 1 is realized.

[0037] It should be noted finally that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A synchronous hydraulic lifting system for a railcar unloading platform, the system comprising: The unloading platform is provided with two groups of A-shaped beams at both ends, a pump station at one side, a hydraulic power mechanism, a control valve group, a control unit, a synchronous control mechanism and two groups of lifting hydraulic cylinders, and the lifting hydraulic cylinders lift the unloading platform on the two groups of A-shaped beams; The synchronous control mechanism includes a synchronous split-flow motor, a wire displacement sensor and a load-sensitive proportional valve, the synchronous split-flow motor has a plurality of oil outlets connected to the lifting hydraulic cylinders through high-pressure oil pipes, the wire displacement sensor is installed between the lifting hydraulic cylinder piston rod and the A-shaped beam, and the load-sensitive proportional valve is located on the oil circuit between the synchronous split-flow motor and the lifting hydraulic cylinder. The control unit is a PLC controller electrically connected with the wire displacement sensor, the control valve group and the load-sensitive proportional valve, receives displacement signals and adjusts hydraulic oil parameters.

2. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 1, wherein: The hydraulic power mechanism includes a three-phase asynchronous motor, a gear hydraulic pump and an oil supply tank, the three-phase asynchronous motor output shaft end is rigidly connected with the input shaft of the hydraulic pump through a shaft coupling, and the oil supply tank is internally provided with an oil suction filter and an oil return filter.

3. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 2, wherein: The control valve group includes an electromagnetic reversing valve and an electric control overflow valve, the electromagnetic reversing valve is a three-position four-way type, and the electric control overflow valve is connected in series on the oil circuit.

4. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 3 wherein: The PLC controller is internally provided with a data cross-validation module, a displacement deviation threshold module and a receiving module.

5. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 4 wherein: The receiving module receives sensor signals, the data cross-validation module receives two types of sensor signals and performs cross-validation, the displacement deviation threshold module is self-defined, and the data cross-validation module controls the load-sensitive proportional valve by comparing the displacement deviation threshold module.

6. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 5, wherein: The synchronous split-flow motor is a gear split-flow motor, and the flow error of the hydraulic oil output by the oil outlet of the synchronous split-flow motor is not more than ±1%.

7. A synchronous hydraulic lifting system for a railcar unloading platform as defined in claim 6 wherein: The synchronous control mechanism further includes an inclination sensor installed at the geometric center of the unloading platform bearing surface, and the inclination sensor and the wire displacement sensor jointly constitute a synchronous error detection unit, and the PLC controller receives two types of sensor signals and performs cross-validation.

8. A synchronous hydraulic lifting system for a railcar unloading platform according to claim 7, wherein: The load-sensitive proportional valve is provided with an operating handle, and the operating handle manually controls the load-sensitive proportional valve.

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