Landing leg stretching control system and crane

Abstract

The invention provides a supporting leg stretching and retracting control system and a crane. The supporting leg stretching and retracting control system comprises a controller, a hydraulic source module and an execution module. The hydraulic source module is connected with the controller and the execution module and used for providing power hydraulic flow for the execution module according to instructions of the controller. The execution module is used for executing the telescopic action of the supporting legs; the hydraulic source module comprises a servo motor, a high-pressure small-displacement pump, a large-displacement pump and a switching valve; the servo motor is connected with the high-pressure small-displacement pump and the large-displacement pump and used for driving the high-pressure small-displacement pump and the large-displacement pump. The switching valve is communicated with the execution module, the high-pressure small-displacement pump and the large-displacement pump and used for switching the working state of the high-pressure small-displacement pump or the working state of the large-displacement pump. The control precision of the horizontal supporting leg is improved, noise in the using process and pressure and flow fluctuation in a hydraulic system are reduced, and the using reliability of the hydraulic system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicles, and in particular relates to a leg extension and retraction control system and a crane. Background Art

[0002] The outrigger hydraulic system of the crane is one of the important components of the crane chassis.

[0003] The outrigger hydraulic system controls the extension of the outriggers in both horizontal and vertical directions, and is used for rigid support of the crane and the supporting surface, thereby improving the crane's working capacity and stability. By operating the outriggers, the crane can be switched between the driving state and the construction state.

[0004] In the existing technical solution, the engine directly provides power to the pump through the power take-off port. Due to the instability of the engine speed, the uncertainty of manual throttle operation and the influence of the engine working state, the speed of the pump is not constant (refer to patent CN 112855650 A). It mainly has the following problems: 1. For example CN 115959586 A, Although proportional valves and pump speed control devices are used, the speed variables introduced by the engine cannot be eliminated. The adjustment lag of the variable pump displacement control mechanism can only improve the accuracy of flow control, but cannot completely solve the interference introduced by the engine. 2. Loud noise during use; 3. For example CN 114909350 A, The suspension hydraulic system introduces a load-sensitive pump and a multi-way valve to form a load-sensitive system. Since the load-sensitive pump is regulated by a mechanical structure and its dynamic response is greatly affected by factors such as processing and assembly, it cannot accurately provide the required pressure for the suspension cylinder, and the pressure fluctuation is small; 4. For example Patent CN 112855650 A, The movement of the horizontal cylinder or the vertical cylinder cannot be accurately controlled. If the horizontal outrigger is in a semi-extended condition, it is inconvenient to align the outrigger pin control and the frame pin control. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a leg extension and retraction control system and a crane to improve the control accuracy of the horizontal legs, reduce the noise during use and the pressure and flow fluctuations in the hydraulic system, and improve the reliability of the hydraulic system.

[0006] In order to achieve the above purpose / solve the above technical problems, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a leg extension and retraction control system, comprising: a controller, a hydraulic source module and an execution module; The hydraulic source module is connected to the controller and the execution module respectively, and is used to provide power hydraulic flow to the execution module according to the instructions of the controller; The execution module is used to execute the leg extension and retraction action; The hydraulic source module includes a servo motor, a high-pressure small-displacement pump, a large-displacement pump and a switching valve; The servo motor is connected to the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to drive the high-pressure small-displacement pump and the large-displacement pump; The switching valve connects the execution module with the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to switch the working state of the high-pressure small-displacement pump or the large-displacement pump, thereby providing power hydraulic flow for the execution module.

[0007] The effect of the above settings is: the hydraulic source module uses a servo motor to drive a high-pressure small-displacement pump and a large-displacement pump to replace the original engine direct adjustment solution, avoiding pump flow fluctuations caused by the engine torque, thereby improving control accuracy.

[0008] If fine flow regulation is required, it can be adjusted by adjusting the speed of the servo motor. If a larger flow regulation is required, a switching valve is used.

[0009] Furthermore, the switching valve is a three-position four-way reversing valve, comprising two input ports, one output port and a control end; The two input ports of the switching valve are connected to a high-pressure small-displacement pump and a large-displacement pump respectively; The output port of the switching valve is connected to the execution module; The control end of the switching valve is connected to the controller. According to the instruction of the controller, the switching valve only connects the high-pressure small-displacement pump to the execution module, only connects the large-displacement pump to the execution module, or connects both the high-pressure small-displacement pump and the large-displacement pump to the execution module.

[0010] The effect of the above settings is: the switching valve receives the controller command, and the controller determines the system flow by determining the speed required by the operating mechanism, thereby determining the position of the switching valve and connecting the large and small displacement pumps. When the flow is small, the switching valve only connects the small displacement pump to the system. When the flow is large, the small displacement pump is disconnected and the large displacement pump is connected to the system. When the flow demand is the largest, both pumps are connected to the system at the same time.

[0011] When the system requires less flow, the system is in a condition where the pump outlet pressure needs to be maintained (when the pressure difference on both sides of the servo valve reaches the set value). At this time, the torque load of the motor is high and the speed is low. In order to improve the working efficiency of the system, reduce the oil film between the friction pairs of the hydraulic pump, and increase the stability of the system at low speed of the servo motor, the system only provides a small flow from the high-pressure small-displacement pump to make up for the system leakage, thereby maintaining this pressure. At the same time, the switching valve controls the large-displacement pump to switch to the unloading state.

[0012] When the system requires a larger flow rate and exceeds the flow threshold of the high-pressure and low-flow working mode, the switching valve controls the high-pressure and low-flow pump to unload, and gradually opens the large-displacement metering pump to supply fluid to the system. Closing the small-displacement pump can reduce the wear and tear of the high-pressure and small-displacement pump. Gradual switching can reduce system pressure and flow fluctuations.

[0013] As the system flow demand increases further, the switching valve can control the small-displacement pump to open, allowing the large and small-displacement pumps to work at the same time, providing more flow for the system.

[0014] Furthermore, the system also includes a safety overflow valve, one end of which is connected to the switching valve, and the other end of which is connected to the oil tank.

[0015] The effect of the above settings: The safety relief valve plays a role of safety protection in the system. When the system pressure exceeds the specified value, the safety valve opens and discharges part of the flow in the system into the oil tank, so that the system pressure does not exceed the allowable value, thereby ensuring that the system does not cause accidents due to excessive pressure.

[0016] Furthermore, when the oil inlet pressure obtained by the pump outlet pressure sensor exceeds the set value of the safety relief valve, the controller controls the servo motor to reduce its speed.

[0017] The effect of the above settings is: the controller controls to reduce the speed of the servo motor when the pressure is too high, thereby reducing the overflow loss of the pump and improving the energy consumption performance of the system.

[0018] Further, the execution module includes at least one group of leg units; A group of the outrigger units includes a horizontal oil cylinder, a vertical oil cylinder, a servo valve 1 and a servo valve 2; The horizontal oil cylinder is used to drive the horizontal legs to extend or retract; the vertical oil cylinder is used to drive the vertical legs to extend or retract; The control end of the servo valve 1 is connected to the controller, one side of the servo valve 1 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the vertical oil cylinder; The control end of the servo valve 2 is connected to the controller, one side of the servo valve 2 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the horizontal oil cylinder.

[0019] The effect of the above settings is: through servo valve 1 and servo valve 2, the controller can control the movement of the horizontal cylinder and the vertical cylinder respectively, and the control is convenient, fast, effective and direct.

[0020] Furthermore, a group of the leg units also includes a pressure sensor 1 and a pressure sensor 2; The pressure sensor 1 is connected to the rod chamber of the horizontal oil cylinder and is connected to the controller, and is used to detect the pressure of the rod chamber of the horizontal oil cylinder; The second pressure sensor is connected to the rodless chamber of the horizontal oil cylinder and is connected to the controller, and is used to detect the pressure of the rodless chamber of the horizontal oil cylinder; The controller compares the detected rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder to determine the state of the horizontal oil cylinder at this time: If the rod chamber pressure of the horizontal cylinder is greater than the rodless chamber pressure, the horizontal cylinder is in a retracted state; If the pressure in the rod chamber of the horizontal cylinder is less than the pressure in the rodless chamber, the horizontal cylinder is in the extended state; If the rod chamber pressure of the horizontal cylinder is equal to the rodless chamber pressure, the horizontal cylinder is in a stationary state; The horizontal cylinder control instruction is compared with the current horizontal cylinder state. If they are different, the servo valve 2 is controlled to switch the oil circuit according to the horizontal cylinder control instruction.

[0021] The effect of the above settings: Through the rod chamber pressure and rodless chamber pressure of the horizontal cylinder, the current state of the horizontal cylinder can be directly judged, and the auxiliary controller can make feedback adjustments to accurately control the horizontal cylinder. The pressure sensor obtains the pressure data in the system, which can ensure the normal operation of the hydraulic system and facilitate system fault diagnosis and maintenance of the outriggers.

[0022] Furthermore, a pump outlet pressure sensor connected to a controller is provided at the output port of the hydraulic source module to collect the hydraulic output pressure of the hydraulic source module; The controller compares the rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder detected, selects the larger pressure, and obtains the larger pressure in the horizontal oil cylinder; The controller calculates the real-time pressure difference according to the larger pressure in the horizontal oil cylinder and the hydraulic output pressure, and the value of the real-time pressure difference is the value of the hydraulic output pressure minus the value of the larger pressure in the horizontal oil cylinder; The controller obtains the set pressure difference △p, and subtracts the real-time pressure difference from the set pressure difference △p to obtain the difference; The horizontal cylinder pressure closed-loop control is performed according to the difference: If the difference is negative, it means that the real-time pressure difference exceeds the set value. At this time, the controller controls to reduce the speed of the servo motor until the difference is 0; If the difference is positive, it means that the real-time pressure difference has not reached the set value, and the controller needs to increase the speed of the servo motor until the difference is 0.

[0023] The effect of the above settings is: the speed of the servo motor is controlled according to the difference, and the pressure difference closed-loop control is realized, which can accurately control the movement of the horizontal cylinder. Through the pressure closed-loop control, the pressure difference before and after the servo valve can be dynamically maintained within a certain range. Within this range, the control accuracy of the servo valve on the flow is much greater than the accuracy when the pressure is uncontrollable.

[0024] Furthermore, a group of the leg units further includes a displacement sensor disposed at the end of the horizontal cylinder, for obtaining the extension length of the horizontal cylinder; The controller obtains the set extension length of the horizontal oil cylinder, and controls the valve opening of the servo valve 2 according to the difference between the extension length of the horizontal oil cylinder and the set extension length.

[0025] The effect of the above settings is: under the premise of a certain pressure difference, the valve opening of servo valve 2 is positively correlated with the displacement of the horizontal cylinder. Through the signal of the displacement sensor, the servo valve can control the displacement of the cylinder in a closed loop.

[0026] Furthermore, the system also includes a level meter disposed on the vehicle frame; the level meter is connected to the controller and is used to collect the levelness of the vehicle; The controller controls the valve opening area of ​​the servo valve 1 according to the horizontality of the vehicle, thereby controlling the extension length of the vertical cylinder.

[0027] The effect of the above settings is as follows: the valve opening of servo valve 1 is positively correlated with the displacement of the vertical cylinder. Through the signal of the level meter, the servo valve can control the displacement of the cylinder in a closed loop.

[0028] Furthermore, when the piston rod of the horizontal oil cylinder needs to be quickly extended or retracted, the controller controls the servo valve 2 to be fully opened, and the servo motor controls the flow rate of the horizontal oil cylinder by volume; When the piston rod of the vertical oil cylinder needs to be extended or retracted quickly, the controller controls the servo valve to fully open, and the servo motor controls the flow rate of the vertical oil cylinder by volume.

[0029] The effect of the above settings is: the servo motor controls the flow rate of the vertical cylinder to reduce the overflow loss of the system while ensuring the rapidity of the piston movement of the horizontal cylinder and the vertical cylinder.

[0030] Further, the execution module includes four groups of leg units; The horizontal cylinders include a left front horizontal cylinder, a left rear horizontal cylinder, a right front horizontal cylinder and a right rear horizontal cylinder, which are respectively distributed at the left front, left rear, right front and right rear of the frame; The horizontal cylinders include a left front horizontal cylinder, a left rear horizontal cylinder, a right front horizontal cylinder and a right rear horizontal cylinder, which are respectively distributed at the left front, left rear, right front and right rear of the frame.

[0031] The effect of the above arrangement is as follows: through the four groups of outrigger units arranged on the frame, the frame balance adjustment and the horizontal and vertical extension of the outriggers can be achieved more directly.

[0032] Furthermore, the system also includes an energy module, which is connected to the hydraulic source module and is used to supply energy to the hydraulic source module.

[0033] Furthermore, the energy module is a battery pack; Alternatively, the energy module is a generator; a voltage stabilizer is provided between the servo motor and the generator.

[0034] Effects of the above settings: This system is essentially a pump control system. The interference factors that affect the speed, such as the throttle and engine status in the original solution, can be eliminated through the action of the voltage stabilizer and the control of the servo motor. The speed of the two quantitative pumps is controlled by the servo motor, with high speed stability and fast speed control response to the controller's signal. Furthermore, the horizontal support leg and the frame are respectively provided with corresponding pin holes, and pin shafts can be inserted into the pin holes to lock the horizontal support leg and the frame; The horizontal supporting leg is provided with pin holes at the fully extended position, the half extended position and the fully retracted position.

[0035] The effect of the above settings is: the horizontal oil cylinder drives the horizontal outrigger to move, and the horizontal outrigger can be extended or retracted. The horizontal outrigger is provided with a first pin hole, and the frame is provided with a second pin hole corresponding to the first pin hole. After the first pin hole and the second pin hole are aligned, the horizontal outrigger reaches the specified position. At this time, a leg pin (pin shaft) is manually inserted between the first pin hole and the second pin hole to ensure that the horizontal outrigger will not move horizontally again, ensuring safety during operation. The horizontal outrigger can be conveniently and firmly locked and fixed by inserting the pin shaft.

[0036] Furthermore, the system also includes a manipulation module connected to the controller; The control module includes: a horizontal outrigger control module and a vertical outrigger control module.

[0037] The horizontal outrigger control module includes: the extension button and retraction button of the horizontal oil cylinder and the button for reaching the designated position with one button (when the water outrigger is extended to the required length and the horizontal outrigger is retracted, the vehicle enters the driving state); The vertical outrigger operating module includes: an extension button and a retraction button for the vertical oil cylinder and a corresponding one-touch button to reach the specified position (to level the vehicle chassis to enter the boarding operation state and to retract the vertical oil cylinder to prepare for the chassis to enter the driving state).

[0038] The button is a virtual button on the screen or a physical button or lever.

[0039] The controller can respond to the input actions of the extension button and the retraction button of the horizontal oil cylinder and the key to reach the designated position by one key, and control the speed of the servo motor, the valve position of the switching valve and the valve opening area of ​​the second servo valve, so that the horizontal oil cylinder performs the corresponding action; The controller can respond to the input actions of the extension button and retraction button of the vertical cylinder and the button for reaching the specified position with one key, control the speed of the servo motor, the valve position of the switching valve and the valve opening area of ​​the servo valve, so that the vertical cylinder performs corresponding actions.

[0040] The effect of the above settings is: the controller is responsible for collecting pressure, position and other signals within the system, and combines the control signals input by the user (such as: extending or retracting horizontal legs, extending or retracting vertical cylinders, the speed of horizontal or vertical cylinder movements, etc.) to control each component in the system to enable the crane to complete the preset actions and move the corresponding components to the specified positions.

[0041] The vertical cylinder extends and retracts, corresponding to the rise and fall of the vehicle. After the lifting, the vehicle chassis and the upper vehicle are lifted up, and the crane enters the upper vehicle operation mode; After the vehicle is lowered, the crane chassis tires touch the ground and the crane is ready to enter driving mode.

[0042] In a second aspect, the present invention provides a crane, comprising a frame and a leg extension and retraction control system as described in the first aspect, which is installed on the frame.

[0043] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can improve the control accuracy of the horizontal outriggers, facilitate the alignment of the outrigger pin holes and save operation time, while reducing noise during use and pressure and flow fluctuations in the hydraulic system, thereby improving the reliability of the hydraulic system.

[0044] 2. The pressure sensor obtains the pressure data in the system, which can ensure the normal operation of the hydraulic system and facilitate the system fault diagnosis and maintenance of the outriggers; 3 、 The maximum pressure of the hydraulic system does not exceed the setting value of the safety relief valve, thereby protecting the safety of all hydraulic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is the hydraulic principle diagram of the present invention; Figure 2 is a control logic diagram of the present invention; Figure 3 It is a schematic diagram of positioning the outrigger pins of the present invention; In the picture ：1. Left front vertical cylinder; 2. Left front horizontal cylinder; 3. Displacement sensor; 4. First pressure sensor; 5. Second pressure sensor; 6. Servo valve 2; 7. Servo valve 1; 13. Right front horizontal cylinder; 14. Right front vertical cylinder; 15. Right rear vertical cylinder; 16. Right rear horizontal cylinder; 21. Safety relief valve; 23. Switching valve; 24. High-pressure small-displacement metering pump; 25. Large-displacement metering pump; 26. Servo motor; 27. Pump outlet pressure sensor; 28. Controller; 36. Left rear horizontal cylinder; 35. Left rear vertical cylinder.

[0046] 001, vertical cylinder; 002, horizontal outrigger fully extended pin hole; 003, horizontal outrigger half extended pin hole; 004, pin hole at any position; 005, frame pin hole; 006, frame; 007, horizontal cylinder.

[0047] △p-pressure difference setting value; up1-oil inlet pressure signal; up2-servo valve outlet pressure; lz-level gauge signal; lx-displacement sensor signal. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0049] In the description of this embodiment, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this embodiment and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this embodiment.

[0050] Definition of Abbreviations:

[0051] Hydraulic power: the product of pressure and flow in the system.

[0052] Pump control system: The flow rate output by the hydraulic pump is adjusted by changing the displacement of the pump or the speed of the prime mover. It is also called a volume control circuit. The pressure oil output by the hydraulic pump completely enters the actuator.

[0053] Variable speed control: By changing the speed of the prime mover, the pump speed is adjusted to control the flow rate in the system.

[0054] Load matching: Open-loop control is adopted to control the servo motor to match the speed of the pump to meet the flow rate required by the load, and there is no need to preset the pressure difference between the pump and the maximum load.

[0055] Maintaining pressure: The hydraulic system maintains a certain pressure.

[0056] One-click: After the operator inputs a single command to the system, the system can automatically execute the set program to achieve one or more set goals. Example 1

[0057] This embodiment provides a leg extension and retraction control system, such as Figure 1 As shown, it includes: a controller 28, a hydraulic source module and an execution module; A hydraulic source module, connected to the controller 28 and the execution module respectively, for providing power hydraulic flow to the execution module according to the instruction of the controller 28; The execution module is used to execute the outrigger extension and retraction action.

[0058] The hydraulic source module includes a servo motor 26, a high-pressure small-displacement pump, a large-displacement pump and a switching valve 23; The servo motor 26 is connected to the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to drive the high-pressure small-displacement pump and the large-displacement pump; The switching valve 23 connects the execution module with the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to switch the working state of the high-pressure small-displacement pump or the large-displacement pump, thereby providing power hydraulic flow for the execution module.

[0059] The hydraulic source module uses a servo motor 26 to drive a high-pressure small-displacement pump and a large-displacement pump to replace the original engine direct adjustment solution, avoiding the flow fluctuation of the pump caused by the engine torque, thereby improving the control accuracy. If fine flow regulation is required, it can be adjusted by adjusting the speed of the servo motor 26. If a larger flow regulation is required, it is performed using a switching valve 23.

[0060] Specifically, the switching valve 23 is a three-position four-way reversing valve, including two input ports, one output port and a control end; The two input ports of the switching valve 23 are connected to a high-pressure small-displacement pump and a large-displacement pump respectively; The output port of the switching valve 23 is connected to the execution module; The control end of the switching valve 23 is connected to the controller 28. According to the instruction of the controller 28, the switching valve 23 only connects the high-pressure small-displacement pump to the execution module, only connects the large-displacement pump to the execution module, or connects both the high-pressure small-displacement pump and the large-displacement pump to the execution module.

[0061] The switching valve 23 receives instructions from the controller 28. The controller 28 determines the speed required by the operating mechanism and the size of the system flow, thereby determining the position of the switching valve 23 and connecting the large and small displacement pumps. When the flow is small, the switching valve 23 only connects the small displacement pump to the system. When the flow is large, the small displacement pump is disconnected and the large displacement pump is connected to the system. When the flow demand is the largest, both pumps are connected to the system at the same time.

[0062] refer to Figure 2 , when the system needs less flow, the system is in the working condition where the pump outlet pressure needs to be maintained (when the pressure difference on both sides of the servo valve 7 reaches the set value), at this time, the torque load of the motor is high and the speed is low. In order to improve the working efficiency of the system, reduce the oil film between the friction pairs of the hydraulic pump, and increase the stability of the system at low speed of the servo motor 26, the system only provides a smaller flow from the high-pressure small-displacement pump to make up for the system leakage, thereby maintaining this pressure. At the same time, the switching valve 23 controls the large-displacement pump to switch to the unloading state.

[0063] When the system needs a larger flow rate and exceeds the flow threshold of the high-pressure and low-flow working mode, the switching valve 23 controls the high-pressure and low-flow pump to unload, and gradually opens the large-displacement metering pump 25 to supply the system with fluid. Closing the small-displacement pump can reduce the wear and tear of the high-pressure and small-displacement pump, and gradual switching can reduce system pressure and flow fluctuations.

[0064] As the flow demand of the system further increases, the switching valve 23 can control the small displacement pump to open, so that the large and small displacement pumps work at the same time, providing more flow for the system.

[0065] Preferably, the system further comprises a safety relief valve 21, one end of the safety relief valve 21 is connected to the switching valve 23, and the other end is connected to the oil tank.

[0066] The safety relief valve 21 plays a role of safety protection in the system. When the system pressure exceeds the specified value, the safety valve opens and discharges part of the flow in the system into the oil tank, so that the system pressure does not exceed the allowable value, thereby ensuring that the system does not cause accidents due to excessive pressure.

[0067] Specifically, when the oil inlet pressure obtained by the pump outlet pressure sensor 27 exceeds the set value of the safety relief valve 21 , the controller 28 controls the speed of the servo motor 26 to be reduced.

[0068] The controller 28 controls to reduce the rotation speed of the servo motor 26 when the pressure is too high, thereby reducing the overflow loss of the pump and improving the energy consumption performance of the system.

[0069] Specifically, the execution module includes at least one set of leg units; A set of outrigger units includes a horizontal cylinder 007, a vertical cylinder 001, a servo valve 1 7 and a servo valve 2 6; The horizontal cylinder 007 is used to drive the horizontal legs to extend or retract; the vertical cylinder 001 is used to drive the vertical legs to extend or retract; The control end of the servo valve 7 is connected to the controller 28, one side of the servo valve 7 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the vertical cylinder 001; The control end of the servo valve 2 6 is connected to the controller 28 , one side of the servo valve 2 6 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the horizontal cylinder 007 .

[0070] Through servo valve 1 7 and servo valve 2 6, the controller 28 can control the movement of the horizontal cylinder 007 and the vertical cylinder 001 respectively, and the control is convenient, fast, effective and direct.

[0071] Specifically, a group of outrigger units also includes pressure sensor 1 and pressure sensor 2; The pressure sensor 1 is connected to the rod chamber of the horizontal oil cylinder 007 and is connected to the controller 28 for detecting the pressure of the rod chamber of the horizontal oil cylinder 007; The second pressure sensor is connected to the rodless chamber of the horizontal oil cylinder 007 and is connected to the controller 28 to detect the pressure of the rodless chamber of the horizontal oil cylinder 007; The controller 28 compares the detected rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder 007 to determine the state of the horizontal oil cylinder 007 at this time: If the pressure in the rod chamber of the horizontal oil cylinder 007 is greater than the pressure in the rodless chamber, the horizontal oil cylinder 007 is in a retracted state; If the pressure in the rod chamber of the horizontal oil cylinder 007 is less than the pressure in the rodless chamber, the horizontal oil cylinder 007 is in the extended state; If the pressure in the rod chamber of the horizontal oil cylinder 007 is equal to the pressure in the rodless chamber, the horizontal oil cylinder 007 is in a stationary state; The control instruction of the horizontal oil cylinder 007 is compared with the state of the horizontal oil cylinder 007 at this time. If they are different, the servo valve 2 6 is controlled to switch the oil circuit according to the control instruction of the horizontal oil cylinder 007.

[0072] The state of the horizontal cylinder 007 at this moment can be directly determined through the rod chamber pressure and the rodless chamber pressure of the horizontal cylinder 007 , and the auxiliary controller 28 performs feedback adjustment to precisely control the horizontal cylinder 007 .

[0073] Specifically, a pump outlet pressure sensor 27 connected to a controller 28 is provided at the output port of the hydraulic source module to collect the hydraulic output pressure of the hydraulic source module; The controller 28 compares the rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder 007 detected, selects the larger pressure, and obtains the larger pressure in the horizontal oil cylinder 007; The controller 28 calculates the real-time pressure difference according to the larger pressure in the horizontal cylinder 007 and the hydraulic output pressure. The value of the real-time pressure difference is the value of the hydraulic output pressure minus the value of the larger pressure in the horizontal cylinder 007. The controller 28 obtains the set pressure difference △p, and subtracts the real-time pressure difference from the set pressure difference △p to obtain a difference; Perform closed-loop pressure control of horizontal cylinder 007 based on the difference: If the difference is negative, it means that the real-time pressure difference exceeds the set value. At this time, the controller 28 controls to reduce the speed of the servo motor 26 until the difference is 0; If the difference is positive, it means that the real-time pressure difference has not reached the set value, and the controller 28 needs to control the increase of the speed of the servo motor 26 until the difference is zero.

[0074] The speed of the servo motor 26 is controlled according to the difference to realize the pressure difference closed loop control, which can accurately control the movement of the horizontal cylinder 007. Through the pressure closed loop control, the pressure difference before and after the servo valve can be dynamically maintained within a certain range. Within this range, the control accuracy of the servo valve on the flow is much greater than the accuracy when the pressure is uncontrollable.

[0075] Specifically, a group of outrigger units also includes a displacement sensor 3 arranged at the end of the horizontal cylinder 007, which is used to obtain the extension length of the horizontal cylinder 007; The controller 28 obtains the set extension length of the horizontal cylinder 007, and controls the valve opening of the servo valve 2 6 according to the difference between the extension length of the horizontal cylinder 007 and the set extension length.

[0076] Under the premise of a certain pressure difference, the valve opening of the servo valve 2 6 is positively correlated with the displacement of the horizontal cylinder 007. Through the signal of the displacement sensor 3, the servo valve can control the displacement of the cylinder in a closed loop.

[0077] The servo motor 26 adjusts the speed and accurately controls the speed of the metering pump, so that the product of the speed n and the displacement V is the value required by the system - the flow Q, Q=n*V, which can accurately provide the required flow for the outrigger system and reduce the flow and pressure fluctuations in the system. The speed of the servo motor 26 can match the load, so that the pump outlet pressure will not exceed the set pressure of the safety relief valve 21, and all the high-pressure oil is supplied to the actuator, avoiding overflow losses in the system and reducing the energy consumption of the crane chassis.

[0078] Specifically, the system further includes a level meter disposed on the vehicle frame 006; the level meter is connected to the controller 28 and is used to collect the levelness of the vehicle; The controller 28 controls the valve opening area of ​​the servo valve 7 according to the horizontality of the vehicle, thereby controlling the extension length of the vertical cylinder 001.

[0079] The valve opening of the servo valve 7 is positively correlated with the displacement of the vertical cylinder 001. Through the signal of the level meter, the servo valve can control the displacement of the cylinder in a closed loop.

[0080] Specifically, when the piston rod of the horizontal oil cylinder 007 needs to be quickly extended or retracted, the controller 28 controls the servo valve 26 to be fully opened, and the servo motor 26 controls the flow of the horizontal oil cylinder 007 by volume; When the piston rod of the vertical oil cylinder 001 needs to be extended or retracted quickly, the controller 28 controls the servo valve 7 to be fully opened, and the servo motor 26 controls the flow rate of the vertical oil cylinder 001 by volume.

[0081] The servo motor 26 controls the flow rate of the vertical cylinder 001 by volume, which can reduce the overflow loss of the system while ensuring the rapidity of the piston movement of the horizontal cylinder 007 and the vertical cylinder 001.

[0082] Specifically, the execution module includes four groups of leg units; The horizontal cylinder 007 includes a left front horizontal cylinder 2, a left rear horizontal cylinder 36, a right front horizontal cylinder 13 and a right rear horizontal cylinder 16, which are respectively distributed at the left front, left rear, right front and right rear of the frame 006; The vertical cylinder 007 includes a left front vertical cylinder 1, a left rear horizontal cylinder 35, a right front horizontal cylinder 14 and a right rear horizontal cylinder 15, which are respectively distributed at the left front, left rear, right front and right rear of the frame 006.

[0083] Through the four groups of outrigger units arranged on the frame 006, the balance adjustment of the frame 006 and the horizontal and vertical extension of the outriggers can be achieved more directly.

[0084] Specifically, the system also includes an energy module, which is connected to the hydraulic source module and is used to supply energy to the hydraulic source module.

[0085] Specifically, the energy module is a battery pack; Alternatively, the energy module is a generator; a voltage stabilizer is provided between the servo motor 26 and the generator.

[0086] This system is essentially a pump control system, which can eliminate the interference factors that affect the speed, such as the throttle and engine status in the original solution, through the action of the voltage stabilizer and the control of the servo motor 26. The speed of the two quantitative pumps is controlled by the servo motor 26, the speed stability is high, and the variable speed control responds to the signal of the controller 28 quickly; like Figure 3 As shown, the horizontal support leg and the frame 006 are respectively provided with corresponding pin holes, and a pin shaft can be inserted into the pin hole to lock the horizontal support leg; The horizontal legs are provided with pin holes at the fully extended position, the half extended position and the fully retracted position.

[0087] refer to Figure 3Schematic diagram of the outrigger pin positioning, when the horizontal outrigger is in the retracted state, the horizontal outrigger fully extended pin hole 002 is aligned with the frame 006 pin hole 005, and the outrigger pin is inserted; when the horizontal outrigger is in the 50% extended condition, the horizontal outrigger half-extended pin hole 003 needs to be aligned with the frame 006 pin hole 005, and the outrigger pin is inserted; the pin hole 004 at any position is aligned with the frame 006 pin hole 005, which represents the working condition of the horizontal outrigger at any extended length, and the outrigger pin also needs to be inserted.

[0088] The horizontal oil cylinder 007 drives the horizontal outrigger to move, and the horizontal outrigger can be extended or retracted. There are corresponding pin holes on the horizontal outrigger and the frame 006. After the pin holes are aligned, the horizontal outrigger reaches the specified position. At this time, a leg pin (pin shaft) is manually inserted between the two pin controls to ensure that the horizontal outrigger will not move horizontally and ensure safety during operation. The horizontal outrigger can be conveniently and firmly locked by inserting the pin shaft.

[0089] Preferably, the system further comprises a manipulation module connected to the controller 28; The control module includes: a horizontal outrigger control module and a vertical outrigger control module.

[0090] The horizontal outrigger control module includes: the extension button and retraction button of the horizontal oil cylinder 007 and the one-key reaching designated position button (when the water outrigger is extended to the required length and the horizontal outrigger is retracted, the vehicle enters the driving state); The vertical outrigger operating module includes: an extension button and a retraction button of the vertical cylinder 001 and a corresponding one-touch button to reach the designated position (leveling the vehicle chassis to enter the boarding operation state and retracting the vertical cylinder 001 to prepare the chassis to enter the driving state).

[0091] The button is a virtual button on the screen or a physical button or lever.

[0092] The controller 28 can respond to the input actions of the extension button and the retraction button of the horizontal cylinder 007 and the key to reach the designated position by one key, and control the speed of the servo motor 26, the valve position of the switching valve 23 and the valve opening area of ​​the servo valve 26, so that the horizontal cylinder 007 performs the corresponding action; The controller 28 can respond to the input actions of the extension button and retraction button of the vertical cylinder 001 and the button for reaching the specified position with one key, and control the rotation speed of the servo motor 26, the valve position of the switching valve 23 and the valve opening area of ​​the servo valve 7, so that the vertical cylinder 001 performs the corresponding action.

[0093] The controller 28 is responsible for collecting pressure, position and other signals within the system, and combines the control signals input by the user (such as: extending or retracting the horizontal cylinder 007, extending or retracting the vertical cylinder 001, the speed of the horizontal or vertical cylinder 001, etc.), to control each component in the system to enable the crane to complete the preset action and move the corresponding components to the specified position.

[0094] The vertical cylinder 001 extends and retracts, corresponding to the rise and fall of the vehicle. After the lifting, the vehicle chassis and the upper vehicle are lifted up, and the crane enters the upper vehicle operation mode; After the vehicle is lowered, the crane chassis tires touch the ground and the crane is ready to enter driving mode.

[0095] By pressing the corresponding button, the system executes the corresponding program until the value read by the system determines that the program is completed.

[0096] like Figure 2 As shown, the controller 28 can execute the following instructions according to the following control logic: 1. Horizontal cylinder 007 extends - one-click extension of the horizontal legs: ① Read the set position; ② Make a difference between Up1-up2 and △p, and the positive and negative values ​​are used to increase or decrease the speed of the servo motor 26, so as to control the flow rate of the horizontal cylinder 007 provided by the pump; ③ Make a difference between the actual position and the displacement sensor 3, so as to control the flow rate required by the horizontal cylinder 007. The larger the difference, the more flow rate is required, and vice versa, the smaller the difference, the smaller the flow rate required by the horizontal cylinder 007. ④ Until the difference between the set position and the value read by the displacement sensor 3 is 0, the extension and retraction of the horizontal cylinder 007 is completed.

[0097] 2. Horizontal cylinder 007 extends - one-button retraction of horizontal legs: ① Retract the horizontal cylinder 007 ② When the difference between the displacement sensor 3 and the set position (restored position) is 0, it is judged that the horizontal cylinder 007 is retracted into position.

[0098] 3. Vertical cylinder 001 - one-button leveling ① Extend the vertical cylinder 001; ② Read the value of the level; ③ Adjust the vertical cylinder 001 at the corresponding position; ④ The level will display the leveling value, and one-click leveling is completed.

[0099] The method of leveling is to adjust the valve opening of the servo valve 2 6 at the higher side of the level gauge accordingly.

[0100] 4. Vertical cylinder 001 - one-button retraction ① Retract all vertical cylinders 001 simultaneously, ② the pump outlet pressure detects that the retraction pressure reaches the set pressure of the safety relief valve 21, ③ hold for three seconds (the set time is subject to the actual situation) to ensure that all vertical cylinders 001 are retracted, ④ complete one-key retraction.

[0101] Specifically, the execution module includes horizontal legs, vertical legs and a controller 28. The horizontal oil cylinder 007 drives the horizontal outrigger to move, and the horizontal outrigger can be extended or retracted. There are corresponding pin controls on the horizontal outrigger and the frame 006. After the pin controls are aligned, the horizontal outrigger reaches the specified position. At this time, a leg pin is manually inserted between the two pin controls to ensure that the horizontal outrigger will no longer move horizontally, thereby ensuring safety during operation.

[0102] The vertical cylinder 001 extends and retracts, corresponding to the raising and lowering of the vehicle. After the raising, the vehicle chassis together with the upper vehicle are lifted, and the crane enters the upper vehicle operation mode; after the vehicle is lowered, the crane chassis tires touch the ground, and the crane is ready to enter the driving mode.

[0103] like Figure 2 As shown, the controller 28 is responsible for collecting pressure, position and other signals in the system, and combines the control signals input by the user (such as: extending or retracting the horizontal outrigger, extending or retracting the vertical cylinder 001, the speed of the horizontal or vertical cylinder 001, etc.), to control the various components in the system to enable the crane to complete the preset action and move the corresponding components to the specified position. In the figure, △p is the pressure difference setting value; up1 is the oil inlet pressure signal; up2 is the servo valve outlet pressure; lz is the level signal; lx is the displacement sensor signal. Example 2

[0104] This embodiment provides a leg extension control system based on a hydraulic system. Figure 2 Control logic diagram, the entire hydraulic system is mainly divided into the following modules: energy source, hydraulic source module, execution module and controller 28 and operation module.

[0105] 1. Energy source module Provides an energy source for the hydraulic source module, acts as a prime mover, and provides the current required by the servo motor 26. And is provided with a voltage stabilizer (refer to Figure 2 ).

[0106] This system is essentially a pump control system, which can eliminate the interference factors that affect the speed, such as the throttle and engine status in the original solution, through the action of the voltage stabilizer and the control of the servo motor 26. The speed of the two quantitative pumps is controlled by the servo motor 26, the speed stability is high, and the variable speed control responds to the signal of the controller 28 quickly.

[0107] (II) Hydraulic source module: It includes a servo motor 26 , a high-pressure small-displacement pump, a large-displacement pump and a switching valve 23 .

[0108] The rotation speed of the servo motor 26 is directly controlled by the controller 28, thereby adjusting the rotation speeds of the two pumps.

[0109] When the system requires less flow, the system is in a working condition where the pump outlet pressure needs to be maintained (when the pressure difference on both sides of the servo valve 7 reaches the set value). At this time, the torque load of the motor is high and the speed is low. In order to improve the working efficiency of the system, reduce the oil film between the friction pairs of the hydraulic pump, and increase the stability of the system when the servo motor 26 is at low speed, the system only provides a smaller flow from the high-pressure small-displacement pump to make up for the system leakage, thereby maintaining this pressure. At the same time, the switching valve 23 controls the large-displacement pump to switch to the unloading state.

[0110] When the system requires a larger flow rate and exceeds the flow threshold of the high-pressure and low-flow working mode, the switching valve 23 controls the high-pressure and low-flow pump to unload, and gradually opens the large-displacement metering pump 25 to supply fluid to the system (closing the small-displacement pump can reduce the wear and tear of the high-pressure and small-displacement pump, and gradual switching can reduce system pressure and flow fluctuations).

[0111] As the flow demand of the system further increases, the switching valve 23 can control the small displacement pump to open, so that the large and small displacement pumps work at the same time, providing more flow for the system.

[0112] (III) Execution module The execution module includes horizontal outriggers and vertical outriggers. The operator can issue control instructions to the crane chassis through the outrigger control module. The control instructions further control the operation of the components in the execution module through the controller 28.

[0113] refer to Figure 3 Schematic diagram of the outrigger pin positioning, when the horizontal outrigger is in the retracted state, the horizontal outrigger fully extended pin hole 002 is aligned with the frame 006 pin hole 005, and the outrigger pin is inserted; when the horizontal outrigger is in the 50% extended condition, the horizontal outrigger half-extended pin hole 003 needs to be aligned with the frame 006 pin hole 005, and the outrigger pin is inserted; the pin hole 004 at any position is aligned with the frame 006 pin hole 005, which represents the working condition of the horizontal outrigger at any extended length, and the outrigger pin also needs to be inserted.

[0114] The execution module can ensure the accuracy of the displacement of the horizontal cylinder 007 when it is extended or retracted, so that the pin hole of the horizontal support is aligned with the pin hole 005 of the frame 006, which can ensure that the vertical support leg can be accurately and quickly extended or retracted to any length.

[0115] (IV) Controller 28 and operating module There are three closed-loop control systems in the controller 28: closed-loop control of pressure, closed-loop control of the vertical cylinder 001 and the level, and closed-loop control of the horizontal cylinder 007 and the displacement sensor 3.

[0116] Pressure closed-loop control: The controller 28 collects the pressure difference between the front and rear sides of the valve in real time, and the set △p is subtracted from the collected pressure difference. ① If the difference is negative, it means that the existing pressure difference exceeds the set value. At this time, the speed of the servo motor 26 is reduced until the difference is 0; ② If the difference is positive, it means that the existing pressure difference has not reached the set value, and the speed of the servo motor 26 needs to be increased until the difference is 0.

[0117] Through pressure closed-loop control, the pressure difference before and after the servo valve can be dynamically maintained within a certain range. Within this range, the control accuracy of the servo valve on the flow is much greater than the accuracy when the pressure is uncontrollable, and once the pump outlet pressure exceeds the set value of the safety relief valve 21, the speed of the servo motor 26 can be immediately reduced, thereby reducing the overflow loss of the pump and improving the energy consumption performance of the system.

[0118] Closed-loop control of vertical cylinder 001: The oil provided by the servo motor 26 with the quantitative pump system flows through the switching valve 2323 and the safety relief valve 21 to the servo valve 7 that controls the vertical cylinder 001. (1) When the vertical cylinder 001 is required to level the vehicle body, the value of the level meter is transmitted to the controller 28, and the servo valve 7 accurately controls the valve opening area (the pressure difference on both sides of the valve is controlled by the pressure closed loop) to ensure that the flow through the servo valve controls the extension length of the vertical cylinder 001; (2) When it is necessary to quickly extend or retract the piston rod of the vertical cylinder 001, the servo valve 7 is fully opened, and the servo motor 26 controls the flow rate in the volume system, thereby reducing the overflow loss of the system and ensuring the rapidity of the piston movement of the vertical cylinder 001.

[0119] Control of horizontal cylinder 007: When the pressure difference before and after the valve is constant (the pressure difference is controlled by the pressure closed loop), the control valve of horizontal cylinder 007 (servo valve 26) together with the displacement sensor 3 of horizontal cylinder 007 forms a displacement closed loop control system to accurately control the displacement of the piston rod of horizontal cylinder 007 and align any pin hole on the horizontal support leg with the pin hole on the frame 006.

[0120] When the piston rod of the horizontal oil cylinder 007 needs to be extended or retracted quickly, the servo valve 7 is fully opened, and the servo motor 26 controls the flow rate in the volume system, thereby reducing the overflow loss of the system and ensuring the rapidity of the piston movement of the vertical oil cylinder 001.

[0121] The control module includes: a horizontal outrigger control module and a vertical outrigger control module.

[0122] The horizontal outrigger control module includes: the extension button and retraction button of the horizontal oil cylinder 007 and the corresponding one-button to reach the specified position (the water outrigger is extended to the required length and the horizontal outrigger is retracted, and the vehicle enters the driving state); The vertical outrigger operating module includes: an extension button and a retraction button of the vertical cylinder 001 and a corresponding one-button button to reach the specified position (leveling the vehicle chassis to enter the boarding operation state and retracting the vertical cylinder 001 to prepare the chassis to enter the driving state).

[0123] The button is a virtual button on the screen or a physical button or lever.

[0124] By pressing the corresponding button, the system executes the corresponding program until the value read by the system determines that the program is completed.

[0125] 1. Horizontal cylinder 007 extends - one-click extension of the horizontal legs: ① Read the set position; ② Make a difference between Up1-up2 and △p, and the positive and negative values ​​are used to increase or decrease the speed of the servo motor 26, so as to control the flow rate of the horizontal cylinder 007 provided by the pump; ③ Make a difference between the actual position and the displacement sensor 3, so as to control the flow rate required by the horizontal cylinder 007. The larger the difference, the more flow rate is required, and vice versa, the smaller the difference, the smaller the flow rate required by the horizontal cylinder 007. ④ Until the difference between the set position and the value read by the displacement sensor 3 is 0, the extension and retraction of the horizontal cylinder 007 is completed.

[0126] 2. Horizontal cylinder 007 extends - one-button retraction of horizontal legs: ① Retract the horizontal cylinder 007 ② When the difference between the displacement sensor 3 and the set position (restored position) is 0, it is judged that the horizontal cylinder 007 is retracted into position.

[0127] 3. Vertical cylinder 001 - one-button leveling ① Extend the vertical cylinder 001; ② Read the value of the level; ③ Adjust the vertical cylinder 001 at the corresponding position; ④ The level will display the leveling value, and one-click leveling is completed.

[0128] 4. Vertical cylinder 001 - one-button retraction ① Retract all vertical cylinders 001 simultaneously, ② the pump outlet pressure detects that the retraction pressure reaches the set pressure of the safety relief valve 21, ③ hold for three seconds (the set time is subject to the actual situation) to ensure that all vertical cylinders 001 are retracted, ④ complete one-key retraction.

[0129] The closed-loop control of the cylinder displacement is an existing and mature technology and will not be elaborated on here.

[0130] This system is essentially a pump control system, which can eliminate the interference factors that affect the speed, such as the throttle and engine status in the original solution, through the action of the voltage stabilizer and the control of the servo motor 26. The speed of the two quantitative pumps is controlled by the servo motor 26, the speed stability is high, and the variable speed control responds to the signal of the controller 28 quickly; This system can accurately control the flow rate and the displacement of the horizontal oil cylinder 007. Through program setting, the extension length of the horizontal oil cylinder 007 can be accurately controlled. The horizontal outriggers can be extended to the set position with one button, which can realize the function of quickly, accurately and automatically unfolding the chassis. After pressing the one-button retraction button, all the horizontal outriggers can be automatically retracted, so that the vehicle can enter the driving state, which greatly saves operation time. This system can accurately control the flow rate and the displacement of the vertical cylinder 001. Through program setting, the vertical cylinder 001 can be automatically extended to support the vehicle and realize the function of leveling the vehicle; all vertical cylinders 001 can be automatically retracted to realize the one-key retraction function, which greatly reduces the adjustment time; The application of high-pressure and low-flow pumps can solve the problem that the servo motor 26 has poor working stability at low speed and low working efficiency of the motor when the hydraulic system has high pressure and low flow, and the oil film of the friction pair of the pump is reduced; the dual pumps in parallel can provide sufficient flow; The system can accurately provide the required flow for the outrigger system, reduce the flow and pressure fluctuations in the system, and the speed of the servo motor 26 can match the load, so that the pump outlet pressure will not exceed the set pressure of the safety relief valve 21, and the high-pressure oil is fully supplied to the actuator, avoiding overflow losses in the system and reducing the energy consumption of the crane chassis; Some existing vehicle chassis use load-sensitive pumps (or electro-hydraulic proportional pumps). After adopting this system, they can be replaced with large and small displacement quantitative pumps, reducing the purchase cost of the pumps. The pressure sensor obtains the pressure data in the system, which can ensure the normal operation of the hydraulic system and facilitate the system fault diagnosis and maintenance of the outriggers; Traditional cranes rely on diesel engines to work and make a lot of noise. Here, the diesel engine is used in conjunction with a generator. The diesel engine always works in its working range with high efficiency and low noise, so the noise will be reduced, which is similar to the working principle of a range-extended vehicle. The present invention solves the problem of high noise during the use of traditional cranes using diesel engines as prime movers; The maximum pressure of the hydraulic system does not exceed the setting value of the safety relief valve 21, thereby protecting the safety of all hydraulic components. Example 3

[0131] This embodiment provides a crane, including a frame 006 and a leg extension and retraction control system as described in the first embodiment installed on the frame 006.

[0132] In other embodiments, the present invention may also adopt the following alternatives: 1) The metering pump can be a gear pump or a vane pump.

[0133] 2) The energy source may be a diesel engine, or may be directly plugged in or use a battery to provide current to the servo motor 26 .

[0134] 3) Due to the symmetry of the outrigger structure, the outrigger can be divided into two control groups, front and rear, and the four groups of pressure sensors at the 001A port of the horizontal and vertical cylinders can be reduced to two groups.

[0135] 4) The two metering pumps can be driven by two servo motors 26 respectively, the switching valve 23 can be removed, and controllable variables can be added to the switching control strategy of the two pumps (the timing and speed of switching will affect the stability of pressure and flow in the system), bringing flexibility to the control of the system.

[0136] 5) The servo valve can be replaced with a proportional valve or a switch valve, and the flow of the actuator module in the input system can be ensured by adjusting the pressure difference on both sides of the valve port (or damping port) by the original components in the hydraulic source module.

[0137] 6) The fixed displacement pump can also be a variable displacement pump, providing the system with more controllable parameters and further improving the system's adaptability to complex working conditions.

[0138] 7) The control of the horizontal cylinder 007 can also be: ① The hydraulic source module makes the pressure difference before and after the control valve constant, and the valve performs open-loop control of the horizontal cylinder 007 (displacement sensor 3 is not required); ② The valve and the horizontal cylinder 007 displacement sensor 3 form a displacement closed-loop control system, and the hydraulic source module is not required to control the pressure difference (only flow is provided).

[0139] The crane outrigger control system of this embodiment can solve the following technical problems: ① In order to allow the horizontal legs to be fully extended, half extended or any other extension length, the displacement can be accurately controlled to save adjustment time during operation.

[0140] ② The vertical legs can be extended or retracted to any length quickly and accurately, greatly reducing the operator's operating time; ③Dual pump system can provide more sufficient flow; ④ The speed is controlled by the servo motor 26. After the system pressure reaches the set value, the motor speed is reduced, which indirectly reduces the overflow loss in the hydraulic system and solves the problem of energy consumption of the crane chassis; ⑤ When the motor of a single fixed displacement pump is at low speed, but the system needs to maintain a certain pump outlet pressure, the system pressure is relatively large and the motor load is also large. This causes the motor to operate at low speed and high torque, with low efficiency and increased wear of the hydraulic pump. Therefore, a high-pressure, small-displacement pump is required to maintain system pressure.

[0141] ⑥Solve the problem of loud noise during use; ⑦ Solve the problem of flow and pressure fluctuations caused by various factors such as throttle, temperature and engine status ⑧The fixed displacement pump can reduce the purchase cost of variable displacement pumps (load sensing pumps, pumps with solenoid valve control, etc.) in traditional outrigger control hydraulic systems.

[0142] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features, and in the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0143] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0144] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0145] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0146] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A leg extension and retraction control system, characterized in that: include: Controller, hydraulic source module and execution module; The hydraulic source module is connected to the controller and the execution module respectively, and is used to provide power hydraulic flow to the execution module according to the instructions of the controller; The execution module is used to execute the leg extension and retraction action; The hydraulic source module includes a servo motor, a high-pressure small-displacement pump, a large-displacement pump and a switching valve; The servo motor is connected to the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to drive the high-pressure small-displacement pump and the large-displacement pump; The switching valve connects the execution module with the high-pressure small-displacement pump and the large-displacement pump respectively, and is used to switch the working state of the high-pressure small-displacement pump or the large-displacement pump, thereby providing power hydraulic flow for the execution module.

2. The outrigger extension and retraction control system according to claim 1, characterized in that: The switching valve is a three-position four-way reversing valve, comprising two input ports, one output port and a control end; The two input ports of the switching valve are connected to a high-pressure small-displacement pump and a large-displacement pump respectively; The output port of the switching valve is connected to the execution module; The control end of the switching valve is connected to the controller. According to the instruction of the controller, the switching valve only connects the high-pressure small-displacement pump to the execution module, only connects the large-displacement pump to the execution module, or connects both the high-pressure small-displacement pump and the large-displacement pump to the execution module.

3. The outrigger extension and retraction control system according to claim 2, characterized in that: The system further comprises a safety relief valve, one end of which is connected to the switching valve and the other end of which is connected to the oil tank; When the oil inlet pressure obtained by the pump outlet pressure sensor exceeds the set value of the safety relief valve, the controller controls the servo motor to reduce the speed.

4. The outrigger extension and retraction control system according to claim 2, characterized in that: The execution module includes at least one group of leg units; A group of the outrigger units includes a horizontal oil cylinder, a vertical oil cylinder, a servo valve 1 and a servo valve 2; The horizontal oil cylinder is used to drive the horizontal legs to extend or retract; the vertical oil cylinder is used to drive the vertical legs to extend or retract; The control end of the servo valve 1 is connected to the controller, one side of the servo valve 1 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the vertical oil cylinder; The control end of the servo valve 2 is connected to the controller, one side of the servo valve 2 is connected to the hydraulic source module, and the other side is connected to the rod chamber and the rodless chamber of the horizontal oil cylinder.

5. The outrigger extension and retraction control system according to claim 4, characterized in that: A group of the leg units also includes a pressure sensor 1 and a pressure sensor 2; The pressure sensor 1 is connected to the rod chamber of the horizontal oil cylinder and is connected to the controller, and is used to detect the pressure of the rod chamber of the horizontal oil cylinder; The second pressure sensor is connected to the rodless chamber of the horizontal oil cylinder and is connected to the controller, and is used to detect the pressure of the rodless chamber of the horizontal oil cylinder; The controller compares the detected rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder to determine the state of the horizontal oil cylinder at this time: If the rod chamber pressure of the horizontal cylinder is greater than the rodless chamber pressure, the horizontal cylinder is in a retracted state; If the pressure in the rod chamber of the horizontal cylinder is less than the pressure in the rodless chamber, the horizontal cylinder is in the extended state; If the rod chamber pressure of the horizontal cylinder is equal to the rodless chamber pressure, the horizontal cylinder is in a stationary state; The horizontal cylinder control instruction is compared with the current horizontal cylinder state. If they are different, the servo valve 2 is controlled to switch the oil circuit according to the horizontal cylinder control instruction.

6. The outrigger extension and retraction control system according to claim 5, characterized in that: A pump outlet pressure sensor connected to a controller is provided at the output port of the hydraulic source module, and is used to collect the hydraulic output pressure of the hydraulic source module; The controller compares the rod chamber pressure and rodless chamber pressure of the horizontal oil cylinder detected, selects the larger pressure, and obtains the larger pressure in the horizontal oil cylinder; The controller calculates the real-time pressure difference according to the larger pressure in the horizontal oil cylinder and the hydraulic output pressure, and the value of the real-time pressure difference is the value of the hydraulic output pressure minus the value of the larger pressure in the horizontal oil cylinder; The controller obtains the set pressure difference △p, and subtracts the real-time pressure difference from the set pressure difference △p to obtain the difference; The horizontal cylinder pressure closed-loop control is performed according to the difference: If the difference is negative, it means that the real-time pressure difference exceeds the set value. At this time, the controller controls to reduce the speed of the servo motor until the difference is 0; If the difference is positive, it means that the real-time pressure difference has not reached the set value, and the controller needs to increase the speed of the servo motor until the difference is 0.

7. The outrigger extension and retraction control system according to claim 6, characterized in that: A group of the leg units further includes a displacement sensor disposed at the end of the horizontal cylinder, for obtaining the extension length of the horizontal cylinder; The controller obtains the set extension length of the horizontal oil cylinder, and controls the valve opening of the servo valve 2 according to the difference between the extension length of the horizontal oil cylinder and the set extension length; and / or, The system also includes a level meter arranged on the frame; the level meter is connected to the controller and is used to collect the levelness of the vehicle; the controller controls the valve opening area of ​​the servo valve 1 according to the levelness of the vehicle, thereby controlling the extension length of the vertical cylinder.

8. The outrigger extension and retraction control system according to claim 5, characterized in that: When the piston rod of the horizontal oil cylinder needs to be extended or retracted quickly, the controller controls the servo valve 2 to be fully opened, and the servo motor controls the flow of the horizontal oil cylinder by volume; When the piston rod of the vertical oil cylinder needs to be extended or retracted quickly, the controller controls the servo valve to fully open, and the servo motor controls the flow rate of the vertical oil cylinder by volume.

9. The outrigger extension and retraction control system according to claim 4, characterized in that: The execution module includes four groups of leg units; The horizontal cylinders include a left front horizontal cylinder, a left rear horizontal cylinder, a right front horizontal cylinder and a right rear horizontal cylinder, which are respectively distributed at the left front, left rear, right front and right rear of the frame; The horizontal cylinders include a left front horizontal cylinder, a left rear horizontal cylinder, a right front horizontal cylinder and a right rear horizontal cylinder, which are respectively distributed at the left front, left rear, right front and right rear of the frame.

10. A crane comprising a frame and a leg extension and retraction control system according to any one of claims 1 to 9 mounted on the frame.

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