Aerial work platform and floating control system therefor

Abstract

An aerial work platform and a floating control system therefor. The system comprises a driving mechanism (5), a hydraulic oil tank (1), a hydraulic pump, a floating control valve (3), a floating mechanism, a movable arm function valve (4), an actuating mechanism, and an energy accumulator (8); the floating control valve (3) comprises a first one-way valve (32), a second one-way valve (33), a pressure reducing valve (34), and a logic valve (31); an oil inlet of the first one-way valve (32) serves as an oil inlet of the floating control valve (3), an oil outlet of the first one-way valve (32) is connected to a pipeline connecting the energy accumulator (8), the pressure reducing valve (34) and the logic valve (31), the logic valve (31) is connected to the second one-way valve (33), and an oil outlet of the second one-way valve (33) serves as a feedback oil port of the floating control valve (3); when the hydraulic pump is a variable displacement pump, the feedback oil ports of the floating control valve (3) and the movable arm function valve (4) are connected to a feedback oil port of the variable displacement pump; and when the hydraulic pump is a constant displacement pump, the feedback oil port of the floating control valve (3) is connected to the feedback oil port of the movable arm function valve (4). Thus, power loss can be reduced, and the reliability of the system can be improved.

Description

Aerial work platform and its floating control system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 16, 2023, with application number 202311027576.2 and invention name “Aerial work platform and its floating control system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the technical field of floating control, and in particular relates to an aerial work platform and a floating control system thereof. Background Art

[0003] Existing aerial work platforms typically achieve off-road performance through undercarriage floating. There are two common methods for achieving this floating function: passive floating, controlled by the vehicle's posture, and active floating, which ensures chassis floating regardless of the vehicle's position. Active floating, as it requires no additional control and offers greater safety than passive floating, is the most common method for aerial work platforms. Due to the specific nature of active floating, a floating hydraulic control system is required to provide a stable standby operating pressure to the floating mechanism, ensuring that the vehicle can float regardless of its posture.

[0004] Existing floating hydraulic control systems, as shown in Figures 1 and 2, all achieve this by controlling a load-sensing variable displacement pump to output a constant pressure. This requires the floating hydraulic control system to continuously provide standby operating pressure to the floating mechanism. In actual operation, floating control results in a significant amount of energy loss. As aerial work platforms are increasingly electrified, this power loss plays a crucial role in improving the endurance of electric products.

[0005] As shown in Figures 1 and 2, the activation of the float function requires an electrical signal control to increase the standby working pressure of the load-sensitive variable pump. Therefore, the reliability of the electrical signal and the solenoid valve largely determines the reliability of the float function, which may in turn affect the safety of the entire machine.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to provide an aerial work platform and a floating control system thereof, so as to solve the problems of large power loss and low reliability existing in the current floating hydraulic control system.

[0008] The present invention solves the above technical problems through the following technical solutions: a floating control system, comprising a drive mechanism, a hydraulic oil tank, a variable pump, a floating control valve, a floating mechanism, a boom function valve, and an actuator, wherein the variable pump is driven by the drive mechanism and its oil inlet is connected to the hydraulic oil tank, the oil outlet of the variable pump is connected to the oil inlets of the floating control valve and the boom function valve, the feedback oil port of the variable pump is connected to the feedback oil ports of the floating control valve and the boom function valve via a feedback oil circuit, the floating control valve is connected to the floating mechanism and the hydraulic oil tank, and the boom function valve is connected to the actuator and the hydraulic oil tank;

[0009] The system also includes an accumulator, and the floating control valve includes a first one-way valve, a second one-way valve, a pressure reducing valve and a logic valve; the oil inlet of the first one-way valve serves as the oil inlet of the floating control valve, and the oil outlet of the first one-way valve is connected to the connecting pipeline of the accumulator, the oil inlet of the pressure reducing valve and the oil inlet of the logic valve, the oil outlet of the logic valve is connected to the oil inlet of the second one-way valve, the oil outlet of the second one-way valve serves as the feedback oil port of the floating control valve, the oil outlet of the pressure reducing valve is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve and the logic valve is also connected to the hydraulic oil tank.

[0010] Furthermore, the boom functional valve includes a steering switch valve, a steering proportional valve, a third one-way valve, a fourth one-way valve, a relief valve and a first unloading valve; the oil inlet of the third one-way valve serves as the oil inlet of the boom functional valve, and the oil outlet of the third one-way valve is connected to the connecting pipeline between the oil inlet of the steering proportional valve and the oil inlet of the relief valve; the oil outlet of the steering proportional valve is connected to the connecting pipeline between the oil inlet of the fourth one-way valve and the return oil port of the steering switch valve, and the oil outlet of the relief valve is connected to the connecting pipeline between the oil inlet of the steering switch valve, the first unloading valve and the hydraulic oil tank; the oil outlet of the fourth one-way valve serves as the feedback oil port of the boom functional valve, and the first unloading valve is also connected to the feedback oil circuit; the oil outlet of the steering switch valve is connected to the actuator.

[0011] Furthermore, the first unloading valve is a two-way flow valve.

[0012] Furthermore, a pressure sensor for detecting the oil outlet pressure is provided at the oil outlet of the variable pump.

[0013] Furthermore, the actuator is a steering cylinder, which includes a left steering cylinder and a right steering cylinder. The left steering cylinder and the right steering cylinder are respectively connected to the oil outlet of the steering switch valve in the boom function valve.

[0014] Furthermore, the driving mechanism is a motor.

[0015] Based on the same concept, the present invention also provides a floating control system, comprising a drive mechanism, a hydraulic oil tank, a metering pump, a floating control valve, a floating mechanism, a boom function valve, and an actuator. The metering pump is driven by the drive mechanism and its oil inlet is connected to the hydraulic oil tank. The oil outlet of the metering pump is connected to the oil inlets of the floating control valve and the boom function valve. The feedback oil port of the floating control valve is connected to the feedback oil port of the boom function valve via a feedback oil circuit. The floating control valve is connected to the floating mechanism and the hydraulic oil tank. The boom function valve is connected to the actuator and the hydraulic oil tank.

[0016] The system also includes an accumulator, and the floating control valve includes a first one-way valve, a second one-way valve, a pressure reducing valve and a logic valve; the oil inlet of the first one-way valve serves as the oil inlet of the floating control valve, and the oil outlet of the first one-way valve is connected to the connecting pipeline of the accumulator, the oil inlet of the pressure reducing valve and the oil inlet of the logic valve, the oil outlet of the logic valve is connected to the oil inlet of the second one-way valve, the oil outlet of the second one-way valve serves as the feedback oil port of the floating control valve, the oil outlet of the pressure reducing valve is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve and the logic valve is also connected to the hydraulic oil tank.

[0017] Furthermore, the boom functional valve includes a steering switch valve, a steering proportional valve, a third one-way valve, a fourth one-way valve, a relief valve and a second unloading valve; the oil inlet of the third one-way valve serves as the oil inlet of the boom functional valve, and the oil outlet of the third one-way valve is connected to the oil inlet of the steering proportional valve, the oil inlet of the relief valve and the connecting pipeline of the first port of the second unloading valve; the oil outlet of the steering proportional valve is connected to the connecting pipeline of the oil inlet of the fourth one-way valve and the return oil port of the steering switch valve, and the oil outlet of the relief valve is connected to the connecting pipeline of the oil inlet of the steering switch valve, the third port of the second unloading valve and the hydraulic oil tank; the oil outlet of the fourth one-way valve serves as the feedback oil port of the boom functional valve, and the second port and the fourth port of the second unloading valve are also connected to the feedback oil circuit; the oil outlet of the steering switch valve is connected to the actuator.

[0018] Furthermore, the second unloading valve includes a two-way flow valve and a three-way flow valve, the first port of the three-way flow valve serves as the first port of the second unloading valve, the first port of the two-way flow valve serves as the second port of the second unloading valve, the second ports of the two-way flow valve and the three-way flow valve serve as the third port of the second unloading valve, and the third port of the three-way flow valve serves as the fourth port of the second unloading valve.

[0019] Based on the same concept, the present invention also provides an aerial work platform, which includes the floating control system as described above. Beneficial effects

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The present invention stores energy in the accumulator when the system is started. The stored accumulator provides a stable standby pressure for the floating mechanism. When the energy in the accumulator is consumed, the variable pump or the metering pump is required to increase the pressure to replenish energy. Therefore, the present invention does not require the variable pump or the metering pump to be in a constant pressure standby state to continuously output high pressure to provide a stable standby pressure for the floating mechanism. The intermittent charging method of the variable pump or the metering pump greatly reduces energy consumption, which is conducive to improving the endurance of the electric aerial work platform.

[0022] The present invention can also store energy in the accumulator when performing other actions, which is more energy-efficient than traditional methods;

[0023] The present invention can realize automatic energy storage of the accumulator, provide a stable oil source for the floating mechanism, reduce control costs and risks caused by control signal failure or control solenoid valve failure, and make the system more stable and reliable;

[0024] Using an accumulator as the standby oil source for the floating mechanism has a faster flow and pressure response than outputting flow and increasing oil pressure through a variable pump or a fixed displacement pump. Therefore, it responds faster to working conditions such as the floating mechanism falling into a pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the description of the embodiment. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] FIG1 is a schematic diagram of a first implementation of a floating hydraulic control system in the background art of the present invention;

[0027] FIG2 is a schematic diagram of a second implementation of a floating hydraulic control system in the background art of the present invention.

[0028] FIG3 is a schematic diagram of a floating control system in Example 1 of the present invention;

[0029] FIG4 is a schematic diagram of a floating control system in Embodiment 2 of the present invention.

[0030] Among them, 1- hydraulic oil tank, 2- load-sensitive variable pump, 21- flow valve of load-sensitive variable pump, 22- cut-off valve of load-sensitive variable pump, 3- floating control valve, 31- logic valve, 32- first one-way valve, 33- second one-way valve, 34- pressure reducing valve, 4- boom function valve, 41- steering switch valve, 42- steering proportional valve, 43- third one-way valve, 44- two-way flow valve, 45- overflow valve, 46- fourth one-way valve, 47- three-way flow valve, 5- driving mechanism, 6- left steering cylinder, 7- right steering cylinder, 8- accumulator, 9- quantitative pump, and the dotted line represents the feedback oil circuit. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solutions of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0032] The following specific embodiments are used to describe the technical solution of the present application in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0033] Example 1

[0034] As shown in Figure 3, a floating control system provided by an embodiment of the present invention includes a drive mechanism 5, a hydraulic oil tank 1, a load-sensing variable pump 2, a floating control valve 3, a floating mechanism, a boom function valve 4, an actuator, and an accumulator 8. The load-sensing variable pump 2 is driven by the drive mechanism 5 and its oil inlet is connected to the hydraulic oil tank 1. The oil outlet P of the load-sensing variable pump 2 is connected to the oil inlets of the floating control valve 3 and the boom function valve 4. The feedback oil port LS of the floating control valve 3 and the boom function valve 4 is connected to the feedback oil port LS of the load-sensing variable pump 2 via a feedback oil circuit. The floating control valve 3 is connected to the accumulator 8, the floating mechanism, and the hydraulic oil tank 1. The boom function valve 4 is connected to the actuator and the hydraulic oil tank 1.

[0035] The floating control valve 3 includes a first one-way valve 32, a second one-way valve 33, a pressure reducing valve 34 and a logic valve 31; the oil inlet of the first one-way valve 32 serves as the oil inlet P of the floating control valve 3, the oil outlet of the first one-way valve 32 is connected to the accumulator 8, the oil inlet of the pressure reducing valve 34 and the connecting pipeline of the oil inlet of the logic valve 31, the oil outlet of the logic valve 31 is connected to the oil inlet of the second one-way valve 33, the oil outlet of the second one-way valve 33 serves as the feedback oil port LS of the floating control valve 3, the oil outlet of the pressure reducing valve 34 is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve 34 and the logic valve 31 is also connected to the hydraulic oil tank 1.

[0036] The boom function valve 4 includes a steering switch valve 41, a steering proportional valve 42, a third one-way valve 43, a fourth one-way valve 46, a relief valve 45 and a two-way flow valve 44; the oil inlet of the third one-way valve 43 serves as the oil inlet P of the boom function valve 4, and the oil outlet of the third one-way valve 43 is connected to the connecting pipeline between the oil inlet of the steering proportional valve 42 and the oil inlet of the relief valve 45; the oil outlet of the steering proportional valve 42 is connected to the connecting pipeline between the oil inlet of the fourth one-way valve 46 and the oil return port of the steering switch valve 41, and the oil outlet of the relief valve 45 is connected to the oil inlet of the steering switch valve 41, the connecting pipeline between the two-way flow valve 44 and the hydraulic oil tank 1; the oil outlet of the fourth one-way valve 46 serves as the feedback oil port LS of the boom function valve 4, and the two-way flow valve 44 is also connected to the feedback oil circuit; the oil outlet of the steering switch valve 41 is connected to the actuator.

[0037] In this embodiment, the driving mechanism 5 is a motor. The actuator is a steering cylinder, which includes a left steering cylinder 6 and a right steering cylinder 7. The left steering cylinder 6 and the right steering cylinder 7 are respectively connected to the oil outlet of the steering switch valve 41.

[0038] When the system starts, the motor drives the load-sensing variable pump 2 to rotate, and the oil at the oil outlet of the load-sensing variable pump 2 enters the floating control valve 3. Since the oil outlet pressure of the load-sensing variable pump 2 (i.e., the oil pressure at the oil outlet) is lower than the set pressure of the logic valve 31 at this time, the oil outlet pressure of the load-sensing variable pump 2 is fed back to the feedback oil port LS of the load-sensing variable pump 2 through the logic valve 31 and the feedback oil circuit; since the steering proportional valve 42 is closed, there is no feedback pressure at the feedback oil port LS of the boom function valve 4. Therefore, only the oil outlet pressure of the load-sensing variable pump 2 is fed back to the feedback oil port LS of the load-sensing variable pump 2. At this time, the flow valve on the load-sensing variable pump 2 is in the right working position due to the effect of feedback pressure, and the load-sensing variable pump 2 continues to output oil at the maximum flow rate, and the oil outlet pressure of the load-sensing variable pump 2 continues to increase; when the oil outlet pressure of the load-sensing variable pump 2 is greater than the nitrogen charging pressure of the accumulator 8, the oil enters the accumulator 8 to store energy, and at the same time reduces the rate of increase of the oil outlet pressure; when the accumulator 8 is full of oil, the oil outlet pressure starts to increase rapidly again. When the oil outlet pressure reaches the set pressure of the logic valve 31, the logic valve 31 reverses, cutting off the oil outlet of the logic valve 31, so that there is no feedback pressure at the feedback oil port LS of the load-sensing variable pump 2. At this time, the feedback oil circuit unloads to the hydraulic oil tank 1 through the two-way flow valve 44 on the boom function valve 4. As the pressure in the feedback oil circuit decreases, the flow valve on the load-sensing variable pump 2 will overcome the spring force and switch to the left working position under the action of the oil outlet pressure. The oil outlet pressure of the load-sensing variable pump 2 enters the variable mechanism of the load-sensing variable pump 2 through the flow valve. The displacement of the oil outlet of the load-sensing variable pump 2 is reduced to near zero output, and the oil outlet pressure of the load-sensing variable pump 2 returns to the standby pressure. This pressure is generally very small, so the power loss is very small.

[0039] Due to the presence of the first one-way valve 32 in the floating control valve 3, the oil in the accumulator 8 can basically maintain the maximum pressure before the oil outlet of the logic valve 31 is cut off, and no pressure is released. At this time, the accumulator 8 serves as the standby oil source of the floating mechanism and continuously provides a stable standby pressure for the floating mechanism.

[0040] When the floating mechanism consumes the oil in the accumulator 8, causing the oil pressure in the accumulator 8 to drop to the set pressure of the logic valve 31, the logic valve 31 is reversed, opening the oil outlet of the logic valve 31, and feeding back the oil outlet pressure of the load sensing variable pump 2 to the feedback oil port LS of the load sensing variable pump 2; since there is feedback pressure at the feedback oil port LS of the load sensing variable pump 2, the flow valve 21 of the load sensing variable pump 2 is reversed to the right working position under the action of the feedback pressure, breaking the balance maintained at the standby pressure, and the variable mechanism of the load sensing variable pump 2 returns to the maximum flow, and the flow rate of its oil outlet increases to replenish the accumulator 8. When the set pressure of the logic valve 31 is reached, the logic valve 31 will cut off the feedback pressure again, and the feedback oil circuit will unload to the hydraulic oil tank 1 through the two-way flow valve 44 on the boom function valve 4 again, and the load sensing variable pump 2 will return to the standby pressure state.

[0041] After completing the energy storage in the accumulator 8, the accumulator 8 provides a stable standby pressure for the floating mechanism, and the load-sensitive variable pump 2 operates in a standby operation state with extremely low power consumption. The load-sensitive variable pump 2 does not need to be continuously on constant pressure standby, which greatly reduces power consumption. At the same time, the system of the present invention can realize fully automatic floating control, and does not need to control the floating function through an electromagnetic valve, which greatly reduces the hidden dangers caused by factors such as control signals and electromagnetic valves, and improves the reliability of the system.

[0042] Because the oil inlet of the float control valve 3 is connected in parallel with other actions (such as steering, travel, and braking), when other actions are performed, the oil inlet pressure of the float control valve 3 increases. Once it exceeds the nitrogen pressure of the accumulator 8, oil is replenished to the accumulator 8. Simultaneously, pressure is directly supplied to the floating mechanism via the first check valve 32 and the pressure reducing valve 34. When the action stops, the presence of the first check valve 32 in the float control valve 3 maintains the oil pressure in the accumulator 8, providing a stable standby pressure for the floating mechanism.

[0043] Example 2

[0044] As shown in Figure 4, a floating control system provided by an embodiment of the present invention includes a drive mechanism 5, a hydraulic oil tank 1, a metering pump 9, a floating control valve 3, a floating mechanism, a boom function valve 4, an actuator, and an accumulator 8. The metering pump 9 is driven by the drive mechanism 5 and its oil inlet is connected to the hydraulic oil tank 1. The oil outlet of the metering pump 9 is connected to the oil inlets of the floating control valve 3 and the boom function valve 4. The feedback oil port LS of the floating control valve 3 is connected to the feedback oil port LS of the boom function valve 4 via a feedback oil circuit. The floating control valve 3 is connected to the accumulator 8, the floating mechanism, and the hydraulic oil tank 1. The boom function valve 4 is connected to the actuator and the hydraulic oil tank 1.

[0045] The floating control valve 3 includes a first one-way valve 32, a second one-way valve 33, a pressure reducing valve 34 and a logic valve 31; the oil inlet of the first one-way valve 32 serves as the oil inlet of the floating control valve 3, and the oil outlet of the first one-way valve 32 is connected to the accumulator 8, the oil inlet of the pressure reducing valve 34 and the connecting pipeline of the oil inlet of the logic valve 31, the oil outlet of the logic valve 31 is connected to the oil inlet of the second one-way valve 33, the oil outlet of the second one-way valve 33 serves as the feedback oil port LS of the floating control valve 3, the oil outlet of the pressure reducing valve 34 is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve 34 and the logic valve 31 is also connected to the hydraulic oil tank 1.

[0046] The boom function valve 4 includes a steering switch valve 41, a steering proportional valve 42, a third one-way valve 43, a fourth one-way valve 46, a relief valve 45, a two-way flow valve 44 and a three-way flow valve 47; the oil inlet of the third one-way valve 43 serves as the oil inlet of the boom function valve 4, and the oil outlet of the third one-way valve 43 is connected to the oil inlet of the steering proportional valve 42, the oil inlet of the relief valve 45 and the connecting pipeline of the three-way flow valve 47; the oil outlet of the steering proportional valve 42 is connected to the oil inlet of the fourth one-way valve 46 and the steering switch On the connecting pipeline of the return oil port of the valve 41, the oil outlet of the relief valve 45 is connected to the oil inlet of the steering switch valve 41, the two-way flow valve 44, the three-way flow valve 47 and the connecting pipeline of the hydraulic oil tank 1; the oil outlet of the fourth one-way valve 46 serves as the feedback oil port LS of the boom function valve 4, the two-way flow valve 44 and the three-way flow valve 47 are also connected to the feedback oil circuit, and the feedback oil port LS pressure of the floating control valve 3 is fed back to the spring side of the three-way flow valve 47; the oil outlet of the steering switch valve 41 is connected to the actuator.

[0047] In this embodiment, the driving mechanism 5 is a motor. The actuator is a steering cylinder, which includes a left steering cylinder 6 and a right steering cylinder 7. The left steering cylinder 6 and the right steering cylinder 7 are respectively connected to the oil outlet of the steering switch valve 41.

[0048] When the system is started, the motor drives the metering pump 9 to rotate, and the outlet of the metering pump 9 outputs a certain flow of oil, causing the outlet pressure of the metering pump 9 to increase. Since the outlet pressure of the metering pump 9 is lower than the set pressure of the logic valve 31 at this time, the outlet pressure of the metering pump 9 is fed back to the three-way flow valve 47 through the logic valve 31 and the feedback oil circuit. The three-way flow valve 47 cannot open to unload under the influence of the outlet pressure and the feedback pressure, and the outlet pressure of the metering pump 9 continues to increase. When the outlet pressure of the metering pump 9 exceeds the nitrogen charging pressure of the accumulator 8, oil enters the accumulator 8 to store energy, while the rate of increase of the outlet pressure is reduced. When the accumulator 8 is full of oil, the outlet pressure begins to increase rapidly again. When the outlet pressure reaches the set pressure of the logic valve 31, the logic valve 31 reverses, shutting off the outlet of the logic valve 31 and further shutting off the feedback oil circuit. The three-way flow valve 47 opens under the influence of the outlet pressure of the metering pump 9, unloading the oil to the hydraulic oil tank 1, and the metering pump 9 is in a standby pressure state.

[0049] Due to the presence of the first one-way valve 32 in the floating control valve 3, the oil in the accumulator 8 can basically maintain the maximum pressure before the oil outlet of the logic valve 31 is cut off, and no pressure is released. At this time, the accumulator 8 serves as the standby oil source of the floating mechanism and continuously provides a stable standby pressure for the floating mechanism.

[0050] When the floating mechanism consumes the oil in the accumulator 8, causing the oil pressure in the accumulator 8 to drop to the set pressure of the logic valve 31, the logic valve 31 is reversed, opening the oil outlet of the logic valve 31, and feeding back the oil outlet pressure of the metering pump 9 to the three-way flow valve 47 through the logic valve 31 and the feedback oil circuit, stopping the unloading; the oil outlet pressure of the metering pump 9 continues to replenish the oil to the accumulator 8.

[0051] After completing the energy storage in the accumulator 8, the accumulator 8 provides a stable standby pressure for the floating mechanism, and the metering pump 9 works in a standby operation state with extremely low power consumption. The metering pump 9 does not need to be continuously on constant pressure standby, which greatly reduces power consumption. At the same time, the system of the present invention can realize fully automatic floating control, and does not need to control the floating function through an electromagnetic valve, which greatly reduces the hidden dangers caused by factors such as control signals and electromagnetic valves, and improves the reliability of the system.

[0052] Because the oil inlet of the float control valve 3 is connected in parallel with other actions (such as steering, travel, and braking), when other actions are performed, the oil inlet pressure of the float control valve 3 increases. Once it exceeds the nitrogen pressure of the accumulator 8, oil is replenished to the accumulator 8. Simultaneously, pressure is directly supplied to the floating mechanism via the first check valve 32 and the pressure reducing valve 34. When the action stops, the presence of the first check valve 32 in the float control valve 3 maintains the oil pressure in the accumulator 8, providing a stable standby pressure for the floating mechanism.

[0053] The above disclosure is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, and they should all be covered by the scope of protection of the present invention.

Claims

1. A floating control system, comprising a driving mechanism, a hydraulic oil tank, a variable pump, a floating control valve, a floating mechanism, a boom function valve and an actuator, wherein the variable pump is driven by the driving mechanism and its oil inlet is connected to the hydraulic oil tank, the oil outlet of the variable pump is connected to the oil inlets of the floating control valve and the boom function valve, the feedback oil port of the variable pump is connected to the feedback oil ports of the floating control valve and the boom function valve through a feedback oil circuit, the floating control valve is connected to the floating mechanism and the hydraulic oil tank, and the boom function valve is connected to the actuator and the hydraulic oil tank; characterized in that: The system also includes an accumulator, and the floating control valve includes a first one-way valve, a second one-way valve, a pressure reducing valve and a logic valve; the oil inlet of the first one-way valve serves as the oil inlet of the floating control valve, the oil outlet of the first one-way valve is connected to the connecting pipeline of the oil inlet of the accumulator, the pressure reducing valve and the oil inlet of the logic valve, the oil outlet of the logic valve is connected to the oil inlet of the second one-way valve, the oil outlet of the second one-way valve serves as the feedback oil port of the floating control valve, the oil outlet of the pressure reducing valve is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve and the logic valve is also connected to the hydraulic oil tank.

2. The floating control system according to claim 1, characterized in that: The boom functional valve includes a steering switch valve, a steering proportional valve, a third one-way valve, a fourth one-way valve, a relief valve and a first unloading valve; the oil inlet of the third one-way valve serves as the oil inlet of the boom functional valve, and the oil outlet of the third one-way valve is connected to the connecting pipeline between the oil inlet of the steering proportional valve and the oil inlet of the relief valve; the oil outlet of the steering proportional valve is connected to the connecting pipeline between the oil inlet of the fourth one-way valve and the oil return port of the steering switch valve, and the oil outlet of the relief valve is connected to the oil inlet of the steering switch valve, the connecting pipeline between the first unloading valve and the hydraulic oil tank; the oil outlet of the fourth one-way valve serves as the feedback oil port of the boom functional valve, and the first unloading valve is also connected to the feedback oil circuit; the oil outlet of the steering switch valve is connected to the actuator.

3. The floating control system according to claim 2, characterized in that: The first unloading valve is a two-way flow valve.

4. The floating control system according to any one of claims 1 to 3, characterized in that: A pressure sensor for detecting the oil outlet pressure is also provided at the oil outlet of the variable pump.

5. The floating control system according to any one of claims 1 to 3, characterized in that: The actuator is a steering cylinder, which includes a left steering cylinder and a right steering cylinder. The left steering cylinder and the right steering cylinder are respectively connected to the oil outlet of the steering switch valve in the boom function valve.

6. The floating control system according to any one of claims 1 to 3, characterized in that: The driving mechanism is a motor.

7. A floating control system, comprising a driving mechanism, a hydraulic oil tank, a metering pump, a floating control valve, a floating mechanism, a boom function valve and an actuator, wherein the metering pump is driven by the driving mechanism and its oil inlet is connected to the hydraulic oil tank, the oil outlet of the metering pump is connected to the oil inlets of the floating control valve and the boom function valve, the feedback oil port of the floating control valve is connected to the feedback oil port of the boom function valve through a feedback oil circuit, the floating control valve is connected to the floating mechanism and the hydraulic oil tank, and the boom function valve is connected to the actuator and the hydraulic oil tank; characterized in that: The system also includes an accumulator, and the floating control valve includes a first one-way valve, a second one-way valve, a pressure reducing valve and a logic valve; the oil inlet of the first one-way valve serves as the oil inlet of the floating control valve, the oil outlet of the first one-way valve is connected to the connecting pipeline of the oil inlet of the accumulator, the pressure reducing valve and the oil inlet of the logic valve, the oil outlet of the logic valve is connected to the oil inlet of the second one-way valve, the oil outlet of the second one-way valve serves as the feedback oil port of the floating control valve, the oil outlet of the pressure reducing valve is connected to the floating mechanism, and the connecting pipeline between the pressure reducing valve and the logic valve is also connected to the hydraulic oil tank.

8. The floating control system according to claim 7, characterized in that: The boom functional valve includes a steering switch valve, a steering proportional valve, a third one-way valve, a fourth one-way valve, a relief valve and a second unloading valve; the oil inlet of the third one-way valve serves as the oil inlet of the boom functional valve, and the oil outlet of the third one-way valve is connected to the connecting pipeline of the oil inlet of the steering proportional valve, the oil inlet of the relief valve and the first port of the second unloading valve; the oil outlet of the steering proportional valve is connected to the connecting pipeline of the oil inlet of the fourth one-way valve and the oil return port of the steering switch valve, and the oil outlet of the relief valve is connected to the connecting pipeline of the oil inlet of the steering switch valve, the third port of the second unloading valve and the hydraulic oil tank; the oil outlet of the fourth one-way valve serves as the feedback oil port of the boom functional valve, and the second port and the fourth port of the second unloading valve are also connected to the feedback oil circuit; the oil outlet of the steering switch valve is connected to the actuator.

9. The floating control system according to claim 8, characterized in that: The second unloading valve includes a two-way flow valve and a three-way flow valve, the first port of the three-way flow valve serves as the first port of the second unloading valve, the first port of the two-way flow valve serves as the second port of the second unloading valve, the second ports of the two-way flow valve and the three-way flow valve serve as the third port of the second unloading valve, and the third port of the three-way flow valve serves as the fourth port of the second unloading valve.

10. An aerial work platform, characterized in that: The aerial work platform comprises a floating control system as claimed in any one of claims 1 to 9.

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