A floating control system for a quantitative pump system

Abstract

The present invention discloses a floating control system for a metering pump system, relating to the technical field of floating mechanisms. The system comprises: a metering pump, a floating control valve, a floating mechanism, a boom functional valve, an actuator, and a control device. The metering pump, floating control valve, and floating mechanism are sequentially connected, and the metering pump, boom functional valve, and actuator are sequentially connected. The floating control valve includes a pressure reducing valve and a floating switching valve, and the boom functional valve includes a fixed differential relief valve and a proportional reversing valve. The fixed differential relief valve and the proportional reversing valve are arranged in parallel between the metering pump and the oil return tank. The floating switching valve and the fixed differential relief valve are connected via a feedback oil circuit, and a check valve is provided between the floating switching valve and the fixed differential relief valve. The actuator is connected to the feedback oil circuit via the proportional reversing valve. This system can provide constant pressure for the floating mechanism without affecting the steering output of the actuator.

Description

Technical Field

[0001] The present invention relates to the technical field of floating mechanisms, and more particularly to a floating control system for a quantitative pump system. Background Art

[0002] In the existing technology, aerial work platforms generally have a floating function in order to improve the off-road performance and operating comfort of the chassis. During the walking action, the hydraulic system needs to provide constant pressure for the floating mechanism to ensure that the floating mechanism can respond in time. In addition, it is also necessary to ensure that the output of the steering action is not affected when the floating mechanism is in effect.

[0003] To meet the control requirements of the above-mentioned aerial work platforms, some aerial work platforms use a fixed-flow pump system. This system usually uses an electric proportional relief valve. When the system is running, the electric proportional relief valve is given a signal to maintain it in a relatively low-pressure standby state. At the same time, when floating constant-pressure standby is required, the current signal of the electric proportional relief valve is adjusted to adjust the pressure of the electric proportional relief valve to maintain the pressure required for floating. In order to ensure that steering can be carried out while walking, the pressure value must also take into account the steering pressure. Due to the relatively high cost of the electric proportional relief valve itself and its high control requirements, it is difficult to match and control it.

[0004] In summary, how to provide a constant pressure to the floating mechanism without affecting the output of the steering action is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, an object of the present invention is to provide a floating control system for a metering pump system, which can provide a constant pressure for a floating mechanism without affecting the steering action output of an actuator.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A floating control system for a metering pump system, comprising: a metering pump, a floating control valve, a floating mechanism, a boom function valve, an actuator, and a control device, wherein the metering pump, the floating control valve, and the floating mechanism are connected in sequence, and the metering pump, the boom function valve, and the actuator are connected in sequence, the floating control valve comprising a pressure reducing valve and a floating switching valve, and the boom function valve comprising a fixed differential relief valve and a proportional reversing valve for controlling the reversing direction of the actuator;

[0008] The differential relief valve and the proportional reversing valve are arranged in parallel between the metering pump and the return oil tank, the floating switching valve and the differential relief valve are connected through a feedback oil circuit, and a one-way valve is provided between the floating switching valve and the differential relief valve, the actuator is connected to the feedback oil circuit through the proportional reversing valve, the motor for driving the metering pump to rotate, the solenoid valve for controlling the action in the floating control valve, and the solenoid valve for controlling the action in the boom function valve are all connected to the control device.

[0009] Preferably, a pressure sensor for detecting system pressure is provided at the outlet of the metering pump, and the pressure sensor is connected to the control device. The control device is used to determine a system failure when the floating control valve and the boom function valve have no output, but the outlet pressure of the metering pump is detected to be higher than the preset range of the standby pressure, so as to control the metering pump to stop running.

[0010] Preferably, the boom functional valve further includes a unloading valve, one end of which is arranged on the feedback oil circuit, and the other end of which is connected to the oil return tank.

[0011] Preferably, the boom functional valve further includes a main overflow valve, one end of which is arranged on the feedback oil circuit and the other end of which is connected to the oil return tank.

[0012] Preferably, a one-way valve is provided at the output end of the metering pump.

[0013] Preferably, the number of the actuators and the proportional reversing valves is greater than or equal to one, and the actuators are connected to the proportional reversing valves in a one-to-one correspondence.

[0014] Preferably, the input end and the output end of the actuator are both connected to the feedback oil circuit through a one-way valve.

[0015] Preferably, the actuator is provided with a detection sensor for monitoring the operation status of the actuator, and the detection sensor is connected to the control device. The control device is used to determine that the boom function valve is faulty when the detection sensor detects that the actuator has an action output but does not output a control signal to the control valve of the actuator, so as to control the system to stop operating.

[0016] Preferably, the actuator is a steering cylinder.

[0017] When using the floating control system of the metering pump system provided by the present invention, when the metering pump starts running, it will output a certain amount of oil into the system. Since this system adopts a differential relief valve, when there is no load feedback to the feedback port of the differential relief valve, the opening pressure of the differential relief valve is the spring set pressure. At this time, the oil flowing out of the metering pump overflows through the differential relief valve, and the overflow pressure is the same as the spring force of the differential relief valve. The system is in a low-pressure standby state.

[0018] When the actuator output is required, the proportional reversing valve is reversed. At this time, the load pressure is fed back to the feedback port of the differential relief valve. Under the simultaneous action of pressure on both sides and spring force, the differential relief valve reduces the valve port, and the outlet pressure of the metering pump increases, thereby allowing more oil to enter the actuator through the proportional reversing valve. At the same time, due to the characteristics of the differential pressure reducing valve, the pressure difference before and after the proportional reversing valve can always remain consistent, that is, the flow of the proportional reversing valve is not affected by the change of load. At the same time, this can realize load-sensitive control of the metering pump system. After the action is completed, the proportional reversing valve slowly returns to the middle position, the feedback oil circuit is unloaded, and the oil at the outlet of the metering pump overflows again through the differential relief valve at low pressure, and the system returns to the low-pressure standby state.

[0019] When the aerial work platform is moving, a stable standby pressure is required to supply the floating mechanism. At this point, the float switching valve switches, and the pressure behind the pressure reducing valve is fed back through the floating switching valve to the feedback port of the differential relief valve. The differential relief valve's orifice decreases under the action of pressure at both ends and the spring force. Since all the working valves are closed, oil accumulates, reducing the valve orifice and the overflow volume, causing the metering pump outlet pressure to rise. Once the pressure reaches the set pressure of the pressure reducing valve, the pressure behind the pressure reducing valve no longer increases, and the feedback pressure in the feedback oil circuit also no longer increases. The differential relief valve's orifice continues to decrease due to the spring force until the metering pump outlet pressure remains at the sum of the feedback pressure behind the pressure reducing valve and the spring set pressure of the differential relief valve. The differential relief valve's orifice remains unchanged, and the system remains balanced. The reduced overflow oil from the differential relief valve's orifice is used to maintain internal system leakage. At this point, the metering pump outlet pressure remains constant, thus providing a stable standby pressure for the floating mechanism.

[0020] This system utilizes a differential relief valve to form a load-sensing system for the fixed displacement pump, achieving low-pressure standby. Simultaneously, the float control valve and feedback oil circuit provide a stable, constant standby pressure for the floating mechanism. Furthermore, a one-way valve is located between the float switching valve and the differential relief valve, ensuring that oil flows only from the float switching valve to the differential relief valve, effectively preventing backflow in the feedback oil circuit. Therefore, the actuator's steering output is not affected when the floating mechanism is in operation. The two mechanisms do not interfere with each other, ensuring that the system's floating, constant-pressure standby operation does not affect the actuator's normal steering output.

[0021] In summary, the floating control system of the metering pump system provided by the present invention can provide a constant pressure for the floating mechanism without affecting the steering action output of the actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0023] Figure 1 This is a schematic diagram of the component connections of the floating control system of the metering pump system provided by the present invention.

[0024] Figure 1 middle:

[0025] 1 is a metering pump, 2 is a floating control valve, 21 is a pressure reducing valve, 22 is a floating switching valve, 3 is a floating mechanism, 4 is a boom function valve, 41 is a differential relief valve, 42 is a proportional reversing valve, 43 is an unloading valve, 44 is a main relief valve, 5 is an actuator, 6 is a pressure sensor, 7 is a return oil tank, 8 is a feedback oil circuit, 9 is a one-way valve, 10 is a detection sensor, and 11 is a control device. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] The core of the present invention is to provide a floating control system for a quantitative pump system, which can provide a constant pressure for a floating mechanism without affecting the steering action output of an actuator.

[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the component connections of the floating control system of the metering pump system provided by the present invention.

[0029] This specific embodiment provides a floating control system for a metering pump system, comprising: a metering pump 1, a floating control valve 2, a floating mechanism 3, a boom function valve 4, an actuator 5, and a control device 11. The metering pump 1, the floating control valve 2, and the floating mechanism 3 are connected in sequence, and the metering pump 1, the boom function valve 4, and the actuator 5 are connected in sequence. The floating control valve 2 includes a pressure reducing valve 21 and a floating switching valve 22. The boom function valve 4 includes a fixed differential relief valve 41 and a proportional reversing valve 42 for controlling the reversing of the actuator 5. The overflow valve 41 and the proportional reversing valve 42 are arranged in parallel between the metering pump 1 and the return oil tank 7. The floating switching valve 22 and the differential overflow valve 41 are connected by a feedback oil circuit 8, and a one-way valve 9 is provided between the floating switching valve 22 and the differential overflow valve 41. The actuator 5 is connected to the feedback oil circuit 8 through the proportional reversing valve 42. The motor for driving the metering pump 1 to rotate, the solenoid valve for controlling the action in the floating control valve 2, and the solenoid valve for controlling the action in the boom function valve 4 are all connected to the control device 11.

[0030] Control device 11 Control device 11 Control device 11 It should be noted that the characteristics of the differential relief valve 41 can make the front and rear pressure difference of the proportional reversing valve 42 always consistent, which means that when the opening of the proportional reversing valve 42 is from fully closed to open, the pressure at the front end of the proportional reversing valve 42 is equal to the pressure at the inlet of the differential relief valve 41, and the pressure at the rear end of the proportional reversing valve 42 is fed back to the spring side of the differential relief valve 41 through the one-way valve 9. Since the characteristic of the differential relief valve 41 is the inlet pressure = feedback port pressure + spring force, the pressure difference between the front and rear ends of the proportional reversing valve 42 at this time = inlet pressure - outlet pressure = spring force of the differential relief valve 41, so under the action of the differential relief valve 41, the inlet and outlet pressure difference of the proportional reversing valve 42 remains unchanged.

[0031] During actual use, the shape, structure, type, position, etc. of the metering pump 1, floating control valve 2, floating mechanism 3, boom function valve 4, actuator 5 and control device 11 can be determined according to actual conditions and actual needs.

[0032] When using the floating control system of the metering pump system provided by the present invention, when the metering pump 1 starts running, it will output a certain amount of oil into the system. Since the system adopts a differential relief valve 41, when there is no load feedback to the feedback port of the differential relief valve 41, the opening pressure of the differential relief valve 41 is the spring set pressure. At this time, the oil flowing out of the metering pump 1 overflows through the differential relief valve 41, and the overflow pressure is the same as the spring force of the differential relief valve 41. The system is in a low-pressure standby state.

[0033] When the actuator 5 needs to output, the proportional reversing valve 42 is reversed. At this time, the load pressure is fed back to the feedback port of the differential relief valve 41. Under the simultaneous action of pressure on both sides and the spring force, the differential relief valve 41 reduces the valve port, and the outlet pressure of the metering pump 1 increases, thereby allowing more oil to enter the actuator 5 through the proportional reversing valve 42. At the same time, due to the characteristics of the differential relief valve 41, the pressure difference before and after the proportional reversing valve 42 can always remain consistent, that is, the flow of the proportional reversing valve 42 is not affected by the change of the load. At the same time, this can achieve load-sensitive control of the metering pump 1 system. After the action is completed, the proportional reversing valve 42 slowly returns to the middle position, the feedback oil circuit 8 is unloaded, and the oil at the outlet of the metering pump 1 overflows again through the differential relief valve 41 at low pressure, and the system returns to the low-pressure standby state.

[0034] When the aerial work platform is moving, it is necessary to provide a stable standby pressure to the floating mechanism 3. At this time, the floating switching valve 22 is switched and connected, and the pressure after the pressure reducing valve 21 is fed back to the feedback port of the differential relief valve 41 through the floating switching valve 22. The valve port of the differential relief valve 41 is reduced under the action of the pressure at both ends and the spring force. At this time, since all the working valve ports are in a closed state, after the oil accumulates, the valve port is reduced and the overflow volume is reduced, the outlet pressure of the metering pump 1 increases. When the pressure increases to the set pressure of the pressure reducing valve 21, the pressure after the pressure reducing valve 21 no longer increases, that is, the feedback pressure of the feedback oil circuit 8 no longer increases. At this time, due to the action of the spring force, the valve port of the differential relief valve 41 will continue to decrease until the pressure at the outlet of the metering pump 1 is maintained at the sum of the feedback pressure after the pressure reducing valve 21 and the spring setting pressure of the differential relief valve 41. The valve port of the differential relief valve 41 no longer changes, and the system maintains balance. The reduced overflow oil due to the reduction in the valve opening of the differential relief valve 41 can be used to maintain internal leakage of the system. At this time, the outlet pressure of the metering pump 1 no longer changes, thereby providing a stable standby pressure for the floating mechanism 3.

[0035] This system utilizes a differential relief valve 41 to form a load-sensing system for the fixed-displacement pump 1, achieving low-pressure standby. Simultaneously, a stable constant-pressure standby pressure is provided to the floating mechanism 3 via the float control valve 2 and feedback oil circuit 8. Furthermore, a check valve 9 is provided between the float switching valve 22 and the differential relief valve 41, ensuring that oil flows only from the float switching valve 22 to the differential relief valve 41, effectively preventing backflow in the feedback oil circuit 8. Consequently, the functioning of the floating mechanism 3 does not affect the steering output of the actuator 5. The two mechanisms do not interfere with each other, ensuring that the system's floating constant-pressure standby operation does not affect the normal steering output of the actuator 5.

[0036] In summary, the floating control system of the metering pump system provided by the present invention can provide a constant pressure for the floating mechanism 3 without affecting the steering action output of the actuator 5 .

[0037] On the basis of the above embodiment, preferably, a pressure sensor 6 for detecting the system pressure is provided at the outlet of the metering pump 1, and the pressure sensor 6 is connected to the control device 11. The control device 11 is used to determine a system failure when the floating control valve 2 and the boom function valve 4 have no output, but the outlet pressure of the metering pump 1 is detected to be higher than the preset range of the standby pressure, so as to control the metering pump 1 to stop running.

[0038] It should be noted that after exiting the metering pump 1, the hydraulic oil is divided into two paths: one to the float control valve 2 and the other to the boom function valve 4. Therefore, the pressure sensor 6 can detect not only the pressure before the pressure reducing valve 21, but also the pressure at the inlet of the boom function valve 4. Therefore, when the solenoid valves on the float control valve 2 and the boom function valve 4 are not outputting, if the pressure sensor 6 detects that the outlet pressure of the metering pump 1 is higher than the preset standby pressure range, the control device 11 will determine that the system has failed and will control the motor driving the metering pump 1 to stop. This ensures that the hydraulic system will shut down in the event of a failure and effectively protect the components.

[0039] Furthermore, it should be noted that the gear pump, one of the components of the metering pump 1, is the primary choice for the hydraulic system power source of aerial work platforms due to its simple structure and strong pollution resistance. The metering pump 1 system, which primarily utilizes a gear pump, utilizes a differential relief valve 41 to form a load-sensing system for the metering pump 1, enabling low-pressure standby. Simultaneously, the floating control circuit provides a stable, constant-pressure standby pressure for the floating mechanism 3. Furthermore, the floating, constant-pressure standby operation does not affect the normal output of the steering action.

[0040] It should also be noted that the gear pump serves as the power source of the hydraulic system. When the motor starts to rotate, a certain amount of oil will be output into the system. Since this system uses a differential relief valve 41, when there is no load feedback to the feedback port of the differential relief valve 41, the opening pressure of the differential relief valve 41 is the spring set pressure, which is generally 15-20 bar. At this time, the oil at the outlet end of the gear pump will overflow through the differential relief valve 41, and the pressure is the same as the spring force of the differential relief valve 41, and the system is in a low-pressure standby state.

[0041] Preferably, the boom functional valve 4 further includes an unloading valve 43 , one end of the unloading valve 43 is provided on the feedback oil circuit 8 , and the other end is connected to the oil return tank 7 .

[0042] It should be noted that when actuator 5 output is required, unloading valve 43 can be switched to the right position, and proportional reversing valve 42 will also be switched to the right position. At this time, load pressure is fed back to the feedback port of differential relief valve 41. Under the combined action of pressure from both sides and spring force, the valve port of differential relief valve 41 will be closed, allowing more oil to enter actuator 5 through proportional reversing valve 42. At the same time, due to the characteristics of differential relief valve 41, the pressure differential across proportional reversing valve 42 remains consistent, which means that the oil flow through proportional reversing valve 42 is not affected by changes in load. At the same time, this achieves load-sensitive control of the metering pump 1 system. When the action of actuator 5 is completed, proportional reversing valve 42 slowly returns to the neutral position, and unloading valve 43 switches to the left position. Feedback oil circuit 8 is unloaded, and the oil at the outlet of metering pump 1 is once again relieved through differential relief valve 41 at low pressure, returning the system to a low-pressure standby state.

[0043] When the aerial work platform is moving, a stable standby pressure needs to be provided for the floating mechanism 3. At this time, the unloading valve 43 is switched to the right position, the floating switching valve 22 is switched and is in a connected state, and the pressure after the pressure reducing valve 21 is fed back to the feedback port of the differential relief valve 41 through the floating switching valve 22 and the one-way valve 9. Under the action of the pressure at both ends and the spring force, the valve opening of the differential relief valve 41 will decrease. At this time, since all the working valve ports are closed, the oil accumulates, and then the outlet pressure of the metering pump 1 increases. When the pressure rises to the set pressure of the pressure reducing valve 21, the pressure after the pressure reducing valve 21 no longer increases, which means that the feedback pressure no longer increases. At this time, due to the action of the spring force, the valve opening of the differential relief valve 41 will continue to decrease until the outlet pressure of the metering pump 1 is maintained at the sum of the feedback pressure after the pressure reducing valve 21 and the spring setting pressure of the differential relief valve 41. The valve opening of the differential relief valve 41 no longer changes, and the system remains balanced. In addition, the overflow oil reduced due to the reduction of the valve port of the differential relief valve 41 can be used to balance the oil leakage inside the system. At this time, the outlet pressure of the metering pump 1 no longer changes, thereby providing a stable standby pressure for the floating mechanism 3.

[0044] On the basis of the above embodiment, preferably, the boom function valve 4 further includes a main overflow valve 44 , one end of which is provided on the feedback oil circuit 8 , and the other end of which is connected to the oil return tank 7 .

[0045] Preferably, a one-way valve 9 is provided at the output end of the metering pump 1 to effectively limit the flow direction of the oil and prevent the oil from flowing back to the metering pump 1 .

[0046] Preferably, the number of the actuators 5 and the proportional reversing valves 42 is greater than or equal to one, and the actuators 5 are connected to the proportional reversing valves 42 in a one-to-one correspondence.

[0047] Preferably, the input end (port A) and the output end (port B) of the actuator 5 are both connected to the feedback oil circuit 8 through a one-way valve 9 .

[0048] It should be noted that the oil flows out from the outlet of the metering pump 1, passes through a one-way valve 9, and reaches the floating control valve 2 and the boom function valve 4. The oil enters the floating mechanism 3 through the pressure reducing valve 21. The floating control oil circuit after the pressure reducing valve 21 is fed back to the boom function valve 4 through the floating switching valve 22 and the one-way valve 9. The main oil circuit inside the boom function valve 4 is connected to the differential relief valve 41 and two proportional reversing valves 42 (three-position four-way reversing valves). When the proportional reversing valve 42 is switched, oil will enter the input end or output end, and then pass into the actuator 5. In addition, the feedback oil circuit 8 of the boom function valve 4 is connected to the feedback port of the differential relief valve 41 and to the inlet of the unloading valve 43. The input and output ends of the actuator 5 are connected to the feedback oil circuit 8 through the one-way valve 9.

[0049] When the float selector valve 22 is switched, the pressure behind the pressure reducing valve 21 is fed back through the check valve 9 to the feedback circuit 8, and then to the feedback port of the differential relief valve 41, reducing the pressure at the differential relief valve 41 and increasing the outlet pressure of the metering pump 1. If a steering action occurs at this time, and the steering pressure is lower than the pressure fed back from the float selector valve 22, the steering load pressure cannot open the check valve 9 on the actuator 5 and be fed back to the feedback circuit 8. Only when the steering pressure is higher than the pressure fed back from the float selector valve 22 will the steering pressure open the check valve 9 on the actuator 5 and reach the feedback circuit 8. At this point, because the steering load pressure in the feedback circuit 8 is higher than the pressure at the float selector valve 22, the check valve 9 on the float selector valve 22 closes again. The feedback circuit 8 can only be subjected to the maximum load, and only the maximum load can be fed back to the feedback circuit 8 to adjust the opening of the differential relief valve 41.

[0050] Based on the above embodiment, preferably, the actuator 5 is provided with a detection sensor 10 for monitoring the operation of the actuator 5. The detection sensor 10 is connected to a control device 11. The control device 11 is used to determine that the boom function valve 4 is faulty when the detection sensor 10 detects that the actuator 5 has an action output but does not output a control signal to the control valve of the actuator 5, so as to control the system to stop operation. At this time, the unloading valve 43 on the boom function valve 4 can be controlled to be energized, cutting off the feedback oil circuit 8 to stop the action of the actuator 5; the motor used to drive the metering pump 1 can also be controlled to stop running to stop the flow output of the metering pump 1, thereby stopping the action of the metering pump 1.

[0051] It should be noted that this system is combined with some electrical components, and the detection sensor 10 can monitor the control valve failure of each actuator 5 in real time, realize fault detection alarm, and can stop the action of the actuator 5 in time after a fault occurs, providing safety protection for the entire aerial work platform.

[0052] It should be noted that when the system is only in a floating output state, assuming that other actuators 5 do not need any output, the system pressure detected by the pressure sensor 6 at this time should be the sum of the spring setting value of the differential relief valve 41 and the setting value of the pressure reducing valve 21. However, if the pressure value detected by the pressure sensor 6 at this time is greater than this value, it can be judged as a system failure. At this time, the control device 11 can send a signal to stop the output current to the unloading valve 43 to unload the feedback oil circuit 8, and the outlet of the metering pump 1 cannot establish a pressure difference. The system determines that the valve group is faulty and sends an alarm signal, which plays a role in safety detection and fault cutting.

[0053] Preferably, the actuator 5 is a steering cylinder.

[0054] It should be noted that the actuator 5 is a steering cylinder. While performing the walking action, it also needs to perform the steering operation. The proportional reversing valve 42 used to control the reversing of the actuator 5 also needs to be reversed accordingly, supplying the oil from the outlet of the metering pump 1 to the actuator 5. As the oil increases, the load pressure at the actuator 5 gradually increases. When the load pressure of the actuator 5 is greater than the set pressure of the pressure reducing valve 21, the load pressure of the actuator 5 begins to play a major role. The valve port of the differential relief valve 41 is further reduced under the action of the spring force, so that the pressure before the proportional reversing valve 42 increases and is always maintained within a range greater than the spring force setting value. Since a one-way valve 9 is provided on the feedback oil circuit 8 after the pressure reducing valve 21, the output of the actuator 5 will not be affected by each other while the system is in constant pressure standby.

[0055] This system uses a gear pump as the system oil source. By feeding back the pressure after the pressure reducing valve 21 to the differential relief valve 41, a floating constant pressure standby mode is achieved. Compared to other methods, this system is simpler, easier to implement, and more energy-efficient, reducing system noise and heat generation. Because the feedback oil circuit 8 of the pressure reducing valve 21 includes a one-way valve 9, constant pressure standby mode does not affect other actions entering the load-sensitive state, making it relatively more energy-efficient. By integrating electrical components with the electrical system, and adding the unloading valve 43 of the feedback oil circuit 8, the safety of the aerial work platform can be effectively prevented from being affected by valve block failures and other factors, resulting in a relatively safer system.

[0056] The load-sensing circuit of the quantitative pump 1 system is formed by the differential relief valve 41, and the floating constant pressure standby is realized through the feedback oil circuit 8 of the pressure reducing valve 21. Moreover, there is no mutual influence between the other actuators 5 during the floating constant pressure standby. By using electrical components and the unloading valve 43 in conjunction with the electrical system, it is possible to monitor and judge the control valve failure of each actuator 5 during floating constant pressure, and to switch in time when a failure occurs, thereby improving the safety and reliability of the system.

[0057] In addition, it should be noted that the orientation or positional relationship indicated by "in and out" etc. in this application is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of simplifying the description and facilitating understanding, 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 the present invention.

[0058] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. Any combination of all the embodiments provided by the present invention is within the scope of protection of this invention and will not be described in detail here.

[0059] The above is a detailed introduction to the floating control system of the metering pump system provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method and core concept of the present invention. It should be noted that, for those skilled in the art, various improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A floating control system for a quantitative pump system, characterized in that: include: A metering pump (1), a floating control valve (2), a floating mechanism (3), a boom function valve (4), an actuator (5), and a control device (11), wherein the metering pump (1), the floating control valve (2), and the floating mechanism (3) are connected in sequence, the metering pump (1), the boom function valve (4), and the actuator (5) are connected in sequence, the floating control valve (2) includes a pressure reducing valve (21) and a floating switching valve (22), and the boom function valve (4) includes a differential relief valve (41) and a proportional reversing valve (42) for controlling the reversing of the actuator (5); The differential relief valve (41) and the proportional reversing valve (42) are arranged in parallel between the metering pump (1) and the return oil tank (7); the floating switching valve (22) and the differential relief valve (41) are connected via a feedback oil circuit (8); and a one-way valve (9) is provided between the floating switching valve (22) and the differential relief valve (41); the actuator (5) is connected to the feedback oil circuit (8) via the proportional reversing valve (42); the motor for driving the metering pump (1) to rotate, the solenoid valve for controlling the action in the floating control valve (2), and the solenoid valve for controlling the action in the boom function valve (4) are all connected to the control device (11).

2. The floating control system of the quantitative pump system according to claim 1, characterized in that: A pressure sensor (6) for detecting system pressure is provided at the outlet of the metering pump (1). The pressure sensor (6) is connected to the control device (11). The control device (11) is used to determine a system failure when the floating control valve (2) and the boom function valve (4) have no output but the outlet pressure of the metering pump (1) is detected to be higher than a preset range of the standby pressure, so as to control the metering pump (1) to stop operating.

3. The floating control system of the quantitative pump system according to claim 1, characterized in that: The boom function valve (4) further includes an unloading valve (43), one end of which is arranged on the feedback oil circuit (8) and the other end of which is connected to the oil return tank (7).

4. The floating control system of the quantitative pump system according to claim 3, characterized in that: The boom function valve (4) further comprises a main overflow valve (44), one end of which is arranged on the feedback oil circuit (8) and the other end of which is connected to the oil return tank (7).

5. The floating control system of a metering pump system according to any one of claims 1 to 4, characterized in that: A one-way valve (9) is provided at the output end of the metering pump (1).

6. The floating control system of a metering pump system according to any one of claims 1 to 4, characterized in that: The number of the actuators (5) and the proportional reversing valves (42) is greater than or equal to one, and the actuators (5) are connected to the proportional reversing valves (42) in a one-to-one correspondence.

7. The floating control system of the quantitative pump system according to claim 6, characterized in that: The input end and the output end of the actuator (5) are both connected to the feedback oil circuit (8) via a one-way valve (9).

8. The floating control system of a metering pump system according to any one of claims 1 to 4, characterized in that: The actuator (5) is provided with a detection sensor (10) for monitoring the operation of the actuator (5). The detection sensor (10) is connected to the control device (11). The control device (11) is used to determine that the boom function valve (4) is faulty when the detection sensor (10) detects that the actuator (5) has an action output but does not output a control signal to the floating control valve (2), so as to control the system to stop operation.

9. The floating control system of a metering pump system according to any one of claims 1 to 4, characterized in that: The actuator (5) is a steering cylinder.

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