Working platform hydraulic system and electric aerial work platform

Abstract

The present application relates to the field of aerial work machinery and discloses a work platform hydraulic system and an electric aerial work platform. The work platform hydraulic system includes a platform cylinder hydraulic circuit and a platform power unit that is arranged on the work platform to supply oil independently to the hydraulic circuit. In the electric aerial work platform using this hydraulic system, a substructure oil pump supplying oil to the main boom working circuit and the platform power unit are independently and distributively distributed. This distributed arrangement enables the platform cylinder hydraulic circuit to be independently supplied with oil by the platform power unit, separating the work platform hydraulic system from other action hydraulic systems. The combination of small-flow and high-pressure platform actions with large-flow and low-pressure actions ensures no pressure redundancy and waste, improving energy efficiency, avoiding complex hydraulic pipeline connections, and achieving long-distance energy transmission.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of Chinese Patent Application No. 202410154055.1 filed on February 2, 2024, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present application relates to aerial work machinery, and specifically, to an electric aerial work platform and a work platform hydraulic system thereof.BACKGROUND

[0003] With the advancement of the electrification process of aerial work platforms, the problem of product endurance has gradually become prominent, and the market is demanding greater energy efficiency and lower power consumption. In the prior art, the driving oil for the three actions of a work platform (swinging, luffing, and leveling) all comes from a substructure oil pump. The oil is controlled and output by a main valve and delivered to a platform control valve through a relatively long pipeline around a boom drag chain. The loss due to the relatively long pipeline, coupled with the structural limitations of the boom drag chain, prevents selecting a large specification for the pipeline, resulting in greater loss along the pipeline and higher energy waste. Usually, when the oil viscosity is low in summer, the energy wasted along the pipeline will account for 10% to 20% of the total energy consumption of the platform actions, while when the oil viscosity is high in winter, this value will be as high as 20% to 30%.SUMMARY

[0004] The purpose of the present application is to provide a work platform hydraulic system and an electric aerial work platform to achieve energy saving and consumption reduction.

[0005] In order to achieve the above purpose, in a first aspect, the present application provides a work platform hydraulic system, including: a platform cylinder hydraulic circuit, including an oil circuit of a fly jib luffing cylinder, an oil circuit of a platform swing cylinder, and an oil circuit of a platform leveling cylinder; and a platform power unit, which is arranged on a work platform and independently supplies oil to the platform cylinder hydraulic circuit, in which the platform power unit includes a motor pump, and a platform hydraulic oil tank arranged on the work platform. The motor pump sucks hydraulic oil from the platform hydraulic oil tank and pumps the hydraulic oil to the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder.

[0006] Optionally, the platform power unit further includes an electric emergency pump and / or a manual emergency pump.

[0007] Optionally, the oil circuit of the platform leveling cylinder includes: a platform leveling cylinder and a leveling proportional directional control valve; and a leveling compensator, in which a hydraulic control end of the leveling compensator is connected to an outlet port of a leveling shuttle valve, and two inlet ports of the leveling shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the leveling proportional directional control valve and the platform leveling cylinder.

[0008] Optionally, the oil circuit of the platform swing cylinder includes: a platform swing cylinder and a swing proportional directional control valve; and a fixed flow valve, arranged at the inlet port of the swing proportional directional control valve.

[0009] Optionally, the oil circuit of the fly jib luffing cylinder includes: a fly jib luffing cylinder and a luffing proportional directional control valve; and a luffing compensator, in which a hydraulic control end of the luffing compensator is connected to an outlet port of a luffing shuttle valve, and two inlet ports of the luffing shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the luffing proportional directional control valve and the fly jib luffing cylinder.

[0010] Optionally, the work platform hydraulic system includes: a load sensing valve, in which a hydraulic control end of the load sensing valve is respectively connected to rod-end chamber working oil circuits and cap-end chamber working oil circuits of the platform leveling cylinder, the fly jib luffing cylinder, and the platform swing cylinder through a shuttle valve.

[0011] Optionally, an exhaust connector is provided in the platform hydraulic oil tank, the exhaust connector is connected to a vent tube, and the vent tube extends out of the platform hydraulic oil tank.

[0012] Optionally, the exhaust connector is connected to a float for floating on the liquid surface, and the float includes a hollow cavity and a gravity block arranged inside the hollow cavity.

[0013] Optionally, an air filter is installed at an extended end of the vent tube.

[0014] In a second aspect, the present application provides an electric aerial work platform, which includes the above work platform hydraulic system.

[0015] Optionally, the electric aerial work platform further includes a main boom working circuit and a substructure oil pump to supply oil to the main boom working circuit, and the substructure oil pump and the platform power unit on the work platform are arranged independently of each other in a distributed manner.

[0016] In the work platform hydraulic system of the present application and the electric aerial work platform using the hydraulic system, a distributed arrangement of hydraulic power is adopted. The platform cylinder hydraulic circuit is independently supplied with oil by the platform power unit, which is additionally arranged on the work platform. Compared with conventional centralized long-distance oil supply, the distributed arrangement avoids complex hydraulic pipeline connections, reduces hydraulic transmission energy consumption, and achieves long-distance electric transmission of energy to the aerial work platform actuator. Moreover, the work platform hydraulic system is separated from other action hydraulic systems of the electric aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency.

[0017] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent DESCRIPTION OF EMBODIMENTS.BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings are used to provide a further understanding of the embodiments of the present application and form part of the specification. They are used to explain the embodiments of the present application together with the following detailed embodiments, but do not constitute a limitation on the embodiments of the present application. For persons of ordinary skill in the art, other drawings can also be obtained based on the structures shown in these drawings without creative efforts. In the drawings: FIG. 1 is a control schematic diagram of the electro-hydraulic drive system of an existing electric aerial work platform; FIG. 2 is a structural schematic diagram of an electric aerial work platform according to an embodiment of the present application; FIG. 3 is a hydraulic schematic diagram of the work platform hydraulic system according to an embodiment of the present application; FIG. 4 is a schematic diagram of the platform hydraulic oil tank in an inclined state in the electric aerial work platform according to an embodiment of the present application; and FIG. 5 and FIG. 6 are schematic diagrams of the platform hydraulic oil tank in FIG. 4 in a horizontal state and an inverted state, respectively. Reference numerals 1Motor pump2Electric emergency pump3Manual emergency pump4High-pressure filter5Main relief valve6Unloading valve7Load sensing valve8Luffing compensator9Luffing proportional directional control valve10Fixed flow valve11Swing proportional directional control valve12Leveling compensator13Leveling proportional directional control valve14First relief valve15Second relief valve16Third relief valve17Fourth relief valve18First balance valve19Fly jib luffing cylinder20Second balance valve21Platform swing cylinder22Third balance valve23Platform leveling cylinder24Platform hydraulic oil tank100Platform power unit200Work platform101Gravity block102Float103Exhaust connector104Vent tube105Air filter DESCRIPTION OF EMBODIMENTS

[0019] The embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the embodiments described herein are only to explain the present application, and are not intended to limit the present application.

[0020] The work platform hydraulic system and electric aerial work platform according to the present application are described below with reference to the drawings.

[0021] As shown in FIG. 1, in the electro-hydraulic drive system of an electric aerial work platform in the prior art, the substructure travelling hydraulic system supplies oil to the superstructure, that is, the substructure oil pump controls the output through the main valve (namely, multi-way valve), and transports the oil to the platform control valve through the relatively long pipeline around the boom drag chain, but there is a loss along the pipeline in the transportation of hydraulic oil through the long pipeline. In practical applications, for an electronically controlled leveling product, during the action of a main boom luffing cylinder, a leveling cylinder also needs to be linked and driven by oil supplied by the system. Under a small-load luffing condition, the oil pressure of the main boom luffing cylinder is generally low, usually about half of the maximum system pressure, while the oil pressure of the leveling oil remains at approximately two-thirds of the maximum system pressure. This will cause the main boom luffing with large flow and low pressure requirements to increase the entire system pressure by about 15% due to the participation of leveling, resulting in energy waste.

[0022] In view of this, the present application provides a new type of work platform hydraulic system, including: a platform cylinder hydraulic circuit; and a platform power unit 100, which is arranged on a work platform 200 and independently supplies oil to the platform cylinder hydraulic circuit.

[0023] Among them, the inventors of the present application deeply realized that, from the comparison of energy utilization rate, the efficiency of electric transmission and electric drive is much higher than that of hydraulic transmission and hydraulic drive. Based on the conventional technologies and the characteristics of aerial work platform transmission and drive, feasible paths for energy saving and consumption reduction include reducing energy losses in components and pipelines, and improving energy conversion and transmission efficiency. Effective measures include reducing the number of hydraulic control components and shortening the length of hydraulic pipelines, using high-efficiency electro-hydraulic components, and improving the system energy distribution efficiency and energy utilization efficiency.

[0024] To this end, the present application separately arranges a platform power unit 100 to independently supply oil to each platform cylinder, without drawing oil from the multi-way valve as shown in FIG. 1. That is, an electric transmission distributed arrangement and a hydraulic system combined with a hydraulic control valve and an actuator are adopted. After the distributed arrangement of the power unit is adopted, long pipelines for hydraulic oil delivery are no longer required, eliminating losses along the flow path, avoiding complex hydraulic pipeline connections, and reducing energy consumption in hydraulic transmission. In addition, since the platform oil source and the main boom luffing are independent of each other, increases in system pressure caused by leveling pressure are avoided, preventing energy waste and thereby improving energy efficiency.

[0025] FIG. 2 is a structural schematic diagram of an electric aerial work platform according to an embodiment of the present application. FIG. 3 is a hydraulic schematic diagram of the work platform hydraulic system according to an embodiment of the present application. As an example, the platform power unit 100 in FIG. 2 and FIG. 3 may include a motor pump 1 and a platform hydraulic oil tank 24 arranged on the work platform 200. The platform cylinder hydraulic circuit includes an oil circuit of a fly jib luffing cylinder, an oil circuit of a platform swing cylinder, and an oil circuit of a platform leveling cylinder. The motor pump 1 sucks hydraulic oil from the platform hydraulic oil tank 24 and pumps the hydraulic oil to the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder. In this way, the platform power unit 100 is arranged on the work platform 200, and the work platform hydraulic system is powered by the independent power unit, which is isolated from other low-pressure and high-flow actuators, reducing the overall energy consumption of the system, and avoiding the problems of long hydraulic oil pipelines, slow response to long-distance transmission, and large pressure loss.

[0026] For emergency use, the platform power unit 100 may further include an electric emergency pump 2 and / or a manual emergency pump 3. When the motor of the platform power unit 100 cannot be used due to a fault or power failure, electric emergency pump 2 or manual emergency pump 3 can be started in emergencies to ensure continuous oil supply for the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder, thereby ensuring the action and safety of the cylinders.

[0027] As shown in FIG. 3, the fly jib luffing, platform swing, and platform leveling actions of the electric aerial work platform are directly driven by the platform power unit 100. The hydraulic power and hydraulic system of the work platform 200 are shown in FIG. 3. The components that constitute a complete hydraulic control system include the hydraulic cylinders, the power unit, the control valves, the balance valves, the filters, the connecting pipelines, and the platform hydraulic oil tank 24.

[0028] Among them, the oil circuit of the platform leveling cylinder may include: a platform leveling cylinder 23 and a leveling proportional directional control valve 13; and a leveling compensator 12, in which a hydraulic control end of the leveling compensator 12 is connected to an outlet port of a leveling shuttle valve, and two inlet ports of the leveling shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the leveling proportional directional control valve 13 and the platform leveling cylinder 23.

[0029] The oil pressure required for the oil circuit of the platform leveling cylinder is relatively high and remains at approximately two-thirds of the maximum system pressure. When the driving cylinder extends, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the cap-end chamber of the platform leveling cylinder 23 after passing through the leveling compensator 12, the leveling proportional directional control valve 13, and the third balance valve 22. The oil in the rod-end chamber flows into the main oil return circuit after passing through the third balance valve 22 and the leveling proportional directional control valve 13, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0030] Similarly, when the driving cylinder retracts, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the rod-end chamber of the platform leveling cylinder 23 after passing through the leveling compensator 12, the leveling proportional directional control valve 13, and the third balance valve 22. The oil in the cap-end chamber of the cylinder flows into the main oil return circuit after passing through the third balance valve 22 and the leveling proportional directional control valve 13, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0031] The leveling compensator 12 ensures that the system flow and pressure are output to the platform leveling cylinder 23 as required by receiving a relatively high-pressure pilot signal transmitted from the leveling shuttle valve. The compensator valve port is open under normal conditions. When the platform leveling cylinder 23 works under load, the relatively high-pressure pilot oil in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit drives the compensator valve core to move, reducing the valve port opening. As the cylinder load increases, the valve port opening decreases, the supply flow decreases, and the piston rod extension speed decreases. Similarly, as the load decreases, the valve port opening increases, the supply flow increases, and the piston rod extension speed increases. As an example, the leveling compensator 12 can be a hydraulically controlled switch valve with continuously adjustable valve port opening.

[0032] In addition, the oil circuit of the platform swing cylinder may include: a platform swing cylinder 21 and a swing proportional directional control valve 11; and a fixed flow valve 10, arranged at the inlet port of the swing proportional directional control valve 11.

[0033] Specifically, when the platform swings to the left, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the left chamber of the platform swing cylinder 21 after passing through the fixed flow valve 10, the swing proportional directional control valve 11, and the second balance valve 20. The oil in the right chamber flows into the main oil return circuit after passing through the second balance valve 20 and the swing proportional directional control valve 11, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0034] When the platform swings to the right, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the right chamber of the platform swing cylinder 21 after passing through the fixed flow valve 10, the swing proportional directional control valve 11, and the second balance valve 20. The oil in the left chamber flows into the main oil return circuit after passing through the second balance valve 20 and the swing proportional directional control valve 11, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0035] The action of the platform leveling cylinder 21 should be smooth, so the fixed flow valve 10 is arranged to supply a stable flow to the leveling cylinder, ensuring that the leveling action is slow and smooth.

[0036] In addition, the oil circuit of the fly jib luffing cylinder may include: a fly jib luffing cylinder 19 and a luffing proportional directional control valve 9; and a luffing compensator 8, in which a hydraulic control end of the luffing compensator 8 is connected to an outlet port of a luffing shuttle valve, and two inlet ports of the luffing shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the luffing proportional directional control valve 9 and the fly jib luffing cylinder 19.

[0037] When the fly jib luffs upward, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the cap-end chamber of the fly jib luffing cylinder 19 after passing through the luffing compensator 8, the luffing proportional directional control valve 9, and the first balance valve 18. The oil in the rod-end chamber flows into the main oil return circuit after passing through the first balance valve 18 and the luffing proportional directional control valve 9, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0038] When the fly jib luffs downward, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the rod-end chamber of the fly jib luffing cylinder 19 after passing through the luffing compensator 8, the luffing proportional directional control valve 9, and the first balance valve 18. The oil in the cap-end chamber flows into the main oil return circuit after passing through the first balance valve 18 and the luffing proportional directional control valve 9, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0039] The function of the luffing compensator 8 is substantially the same as that of the leveling compensator 12. The luffing compensator 8 ensures that the system flow and pressure are output to the luffing proportional directional control valve 9 as required by receiving a relatively high-pressure pilot signal in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit transmitted by the luffing shuttle valve. The compensator valve port is open under normal conditions, and when the fly jib luffing cylinder 19 works under load, the relatively high-pressure pilot oil in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit drives the compensator valve core to move, reducing the valve port opening. As the cylinder load increases, the valve port opening decreases, the supply flow decreases, and the piston rod extension speed decreases. Similarly, as the load decreases, the valve port opening increases, the supply flow increases, and the piston rod extension speed increases.

[0040] In the embodiment of FIG. 3, the work platform hydraulic system may further include: a load sensing valve 7, in which a hydraulic control end of the load sensing valve 7 is respectively connected to rod-end chamber working oil circuits and cap-end chamber working oil circuits of the platform leveling cylinder 23, the fly jib luffing cylinder 19, and the platform swing cylinder 21 through a shuttle valve.

[0041] It can be seen that the hydraulic control end of the load sensing valve 7 obtains the highest pressure in each load working oil circuit. On this basis, pressure relief or oil replenishment is carried out according to load requirements, ensuring that the flow and pressure of the main oil inlet circuit are output as required by the system.

[0042] A main relief valve 5 is arranged in the hydraulic system of FIG. 3, and its relief pressure serves as the highest pressure of the system. When the relief pressure of the main relief valve is exceeded, the main overflow valve 5 is actuated to relieve pressure in the main oil inlet circuit. In addition, the working oil circuits of the fly jib luffing cylinder 19 and the platform leveling cylinder 23 are also arranged with a first relief valve 14, a second relief valve 15, a third relief valve 16, and a fourth relief valve 17 for overpressure relief to ensure the safety of the actuators.

[0043] In addition, because the platform power unit 100 consists of the platform hydraulic oil tank 24 and the motor pump 1, the platform power unit 100 is arranged on the work platform 200. When a leveling action is performed, the hydraulic oil tank appears in three states: tilted, horizontal, and inverted. If a conventional oil tank is used, when the oil tank is tilted or inverted, a problem of oil leakage through the air filter 105 may occur.

[0044] To solve this problem, the present application provides a specially designed internal structure for the hydraulic oil tank. As shown in FIG. 4, an exhaust connector 103 is arranged in the platform hydraulic oil tank 24 in this embodiment, and the exhaust connector 103 is connected to a vent tube 104, and the vent tube 104 extends out of the platform hydraulic oil tank 24. The air in the oil tank can be discharged or replenished in time through the exhaust connector 103 and the vent tube 104.

[0045] However, when the position of the oil tank is uncertain, it is necessary to ensure that the exhaust connector 103 is always in the air chamber in the oil tank so that the oil tank can breathe smoothly. Because the oil tank may be inverted, it is impossible to fix the exhaust connector 103 on the inner wall of the oil tank or arrange it in the center. These fixing methods are not feasible as they may easily cause the exhaust connector 103 to be submerged in oil, preventing the oil tank from breathing.

[0046] In particular, the exhaust connector 103 shown in FIG. 4 is connected to a float 102 for floating on the liquid surface, and the float 102 includes a hollow cavity and a gravity block 101 arranged inside the hollow cavity. Under the action of the gravity block 101 that can move freely in the cavity, the float 102 can always float on the liquid surface of the oil tank regardless of the position of the oil tank, as shown in FIG. 5 and FIG. 6. The float 102 can be a sphere as shown in the figures, a square box, or the like, and the gravity block 101 can be a metal sphere, a square metal block, or the like. The shape is not limited. With such an arrangement, the problem of oil leakage in the oil tank air filter when the platform is tilted or inverted can be solved.

[0047] An extended end of the vent tube 104 may also be arranged with the air filter 105 to prevent external contaminants from entering the oil tank. The function of the vent tube 104 is to connect the exhaust connector 103 with the air filter 105. Among them, the gravity block 101, the float 102, and the exhaust connector 103 can be separate bodies assembled as a whole, or they can be an integrated structure. The purpose is to enable the exhaust port of the exhaust connector 103 to remain in the air within the oil tank body outside the hydraulic oil level, regardless of the posture of the platform hydraulic oil tank 24. When the platform power unit 100 works and the oil in the oil tank decreases, the outside air can enter the oil tank through the air filter 105, the vent tube 104, and the exhaust connector 103; when the oil in the platform hydraulic oil tank 24 increases, the air inside the oil tank is discharged from the oil tank through the exhaust connector 103, the vent tube 104, and the air filter 105.

[0048] The above intake and exhaust design of the platform hydraulic oil tank 24 ensures smooth air intake and exhaust of the oil tank; it also ensures that, regardless of the posture or angle of the platform, the hydraulic oil will not leak out through the air filter 105.

[0049] The above work platform hydraulic system can be applied to various aerial work platforms, especially electric aerial work platforms, which is more energy-saving and consumption-reducing, and simplifies the layout of hydraulic pipelines.

[0050] When the above independent oil supply work platform hydraulic system is adopted, other actuators of the electric aerial work platform, such as each main boom working circuit of the main boom, can be supplied with oil through the substructure oil pump (not shown), and the substructure oil pump and the platform power unit 100 on the work platform 200 are arranged independently and distributedly.

[0051] By designing distributed hydraulic power and control for the work platform, the work platform hydraulic system is separated from other action hydraulic systems of the electric aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency. The intake and exhaust design of the hydraulic oil tank can ensure smooth air intake and exhaust of the oil tank; it can also ensure that, regardless of the posture or angle of the platform, the hydraulic oil will not leak out through the air filter.

[0052] In summary, in the work platform hydraulic system of the present application and the electric aerial work platform using the hydraulic system, distributed hydraulic power and control for the work platform are used to replace the centralized long-distance oil supply in the prior art, which avoids complex hydraulic pipeline connections, reduces hydraulic transmission energy consumption, and achieves long-distance energy transmission of the aerial work platform actuator, thereby improving energy efficiency. The distributed hydraulic power and control for the work platform separate the platform hydraulic system from other action hydraulic systems of the aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency.

[0053] In the description of the present application, it should be understood that the terms "first" and "second" are used merely for illustrative purposes and shall not be construed as indicating or implying relative importance or as implicitly specifying the number of technical features referred to. To this end, the features defined with the terms "first" and "second" may explicitly or implicitly include at least one of the features. In the context of the present application, unless otherwise specifically defined, "multiple" means at least two, for example, two or three.

[0054] In the present application, unless otherwise expressly specified and defined, the terms "mount", "be connected to", "be connected with", "fix", and so forth shall be interpreted in a broad sense. For example, the connection can be fixed connection, detachable connection, integrated connection, mechanical connection, electrical connection, connection capable of communicating with each other, direct connection, indirect connection through intermediate media, connection between two components or interaction between two components, unless otherwise specifically defined. For those of ordinary skill in the art, the specific meaning of the preceding terms in the present application can be understood according to the specific situation.

[0055] In the description of the specification, descriptions with reference to the terms "an embodiment", "some embodiments", "example", "specific example", or "some examples" mean that specific features, structures, materials, or characteristics described in combination with the embodiment or example are contained in at least an embodiment or example of the present application. In the specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Furthermore, the technicians in this field may combine different embodiments or examples described in the specification and features of different embodiments or examples without contradiction.

[0056] Although the embodiment of the present application has been shown and described above, it can be understood that the above embodiment is exemplary and cannot be understood as a limitation on the present application. The changes, modifications, replacements, and improvements can be made to the above embodiment within the scope of the present application for ordinary persons skilled in the art.

Examples

Embodiment Construction

[0019]The embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the embodiments described herein are only to explain the present application, and are not intended to limit the present application.

[0020]The work platform hydraulic system and electric aerial work platform according to the present application are described below with reference to the drawings.

[0021]As shown in FIG. 1, in the electro-hydraulic drive system of an electric aerial work platform in the prior art, the substructure travelling hydraulic system supplies oil to the superstructure, that is, the substructure oil pump controls the output through the main valve (namely, multi-way valve), and transports the oil to the platform control valve through the relatively long pipeline around the boom drag chain, but there is a loss along the pipeline in the transportation of hydraulic oil through the long pipeline. In practical applications, for ...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of Chinese Patent Application No. 202410154055.1 filed on February 2, 2024, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present application relates to aerial work machinery, and specifically, to an electric aerial work platform and a work platform hydraulic system thereof.BACKGROUND

[0003] With the advancement of the electrification process of aerial work platforms, the problem of product endurance has gradually become prominent, and the market is demanding greater energy efficiency and lower power consumption. In the prior art, the driving oil for the three actions of a work platform (swinging, luffing, and leveling) all comes from a substructure oil pump. The oil is controlled and output by a main valve and delivered to a platform control valve through a relatively long pipeline around a boom drag chain. The loss due to the relatively long pipeline, coupled with the structural limitations of the boom drag chain, prevents selecting a large specification for the pipeline, resulting in greater loss along the pipeline and higher energy waste. Usually, when the oil viscosity is low in summer, the energy wasted along the pipeline will account for 10% to 20% of the total energy consumption of the platform actions, while when the oil viscosity is high in winter, this value will be as high as 20% to 30%.SUMMARY

[0004] The purpose of the present application is to provide a work platform hydraulic system and an electric aerial work platform to achieve energy saving and consumption reduction.

[0005] In order to achieve the above purpose, in a first aspect, the present application provides a work platform hydraulic system, including: a platform cylinder hydraulic circuit, including an oil circuit of a fly jib luffing cylinder, an oil circuit of a platform swing cylinder, and an oil circuit of a platform leveling cylinder; and a platform power unit, which is arranged on a work platform and independently supplies oil to the platform cylinder hydraulic circuit, in which the platform power unit includes a motor pump, and a platform hydraulic oil tank arranged on the work platform. The motor pump sucks hydraulic oil from the platform hydraulic oil tank and pumps the hydraulic oil to the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder.

[0006] Optionally, the platform power unit further includes an electric emergency pump and / or a manual emergency pump.

[0007] Optionally, the oil circuit of the platform leveling cylinder includes: a platform leveling cylinder and a leveling proportional directional control valve; and a leveling compensator, in which a hydraulic control end of the leveling compensator is connected to an outlet port of a leveling shuttle valve, and two inlet ports of the leveling shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the leveling proportional directional control valve and the platform leveling cylinder.

[0008] Optionally, the oil circuit of the platform swing cylinder includes: a platform swing cylinder and a swing proportional directional control valve; and a fixed flow valve, arranged at the inlet port of the swing proportional directional control valve.

[0009] Optionally, the oil circuit of the fly jib luffing cylinder includes: a fly jib luffing cylinder and a luffing proportional directional control valve; and a luffing compensator, in which a hydraulic control end of the luffing compensator is connected to an outlet port of a luffing shuttle valve, and two inlet ports of the luffing shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the luffing proportional directional control valve and the fly jib luffing cylinder.

[0010] Optionally, the work platform hydraulic system includes: a load sensing valve, in which a hydraulic control end of the load sensing valve is respectively connected to rod-end chamber working oil circuits and cap-end chamber working oil circuits of the platform leveling cylinder, the fly jib luffing cylinder, and the platform swing cylinder through a shuttle valve.

[0011] Optionally, an exhaust connector is provided in the platform hydraulic oil tank, the exhaust connector is connected to a vent tube, and the vent tube extends out of the platform hydraulic oil tank.

[0012] Optionally, the exhaust connector is connected to a float for floating on the liquid surface, and the float includes a hollow cavity and a gravity block arranged inside the hollow cavity.

[0013] Optionally, an air filter is installed at an extended end of the vent tube.

[0014] In a second aspect, the present application provides an electric aerial work platform, which includes the above work platform hydraulic system.

[0015] Optionally, the electric aerial work platform further includes a main boom working circuit and a substructure oil pump to supply oil to the main boom working circuit, and the substructure oil pump and the platform power unit on the work platform are arranged independently of each other in a distributed manner.

[0016] In the work platform hydraulic system of the present application and the electric aerial work platform using the hydraulic system, a distributed arrangement of hydraulic power is adopted. The platform cylinder hydraulic circuit is independently supplied with oil by the platform power unit, which is additionally arranged on the work platform. Compared with conventional centralized long-distance oil supply, the distributed arrangement avoids complex hydraulic pipeline connections, reduces hydraulic transmission energy consumption, and achieves long-distance electric transmission of energy to the aerial work platform actuator. Moreover, the work platform hydraulic system is separated from other action hydraulic systems of the electric aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency.

[0017] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent DESCRIPTION OF EMBODIMENTS.BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings are used to provide a further understanding of the embodiments of the present application and form part of the specification. They are used to explain the embodiments of the present application together with the following detailed embodiments, but do not constitute a limitation on the embodiments of the present application. For persons of ordinary skill in the art, other drawings can also be obtained based on the structures shown in these drawings without creative efforts. In the drawings: FIG. 1 is a control schematic diagram of the electro-hydraulic drive system of an existing electric aerial work platform; FIG. 2 is a structural schematic diagram of an electric aerial work platform according to an embodiment of the present application; FIG. 3 is a hydraulic schematic diagram of the work platform hydraulic system according to an embodiment of the present application; FIG. 4 is a schematic diagram of the platform hydraulic oil tank in an inclined state in the electric aerial work platform according to an embodiment of the present application; and FIG. 5 and FIG. 6 are schematic diagrams of the platform hydraulic oil tank in FIG. 4 in a horizontal state and an inverted state, respectively. Reference numerals 1Motor pump2Electric emergency pump3Manual emergency pump4High-pressure filter5Main relief valve6Unloading valve7Load sensing valve8Luffing compensator9Luffing proportional directional control valve10Fixed flow valve11Swing proportional directional control valve12Leveling compensator13Leveling proportional directional control valve14First relief valve15Second relief valve16Third relief valve17Fourth relief valve18First balance valve19Fly jib luffing cylinder20Second balance valve21Platform swing cylinder22Third balance valve23Platform leveling cylinder24Platform hydraulic oil tank100Platform power unit200Work platform101Gravity block102Float103Exhaust connector104Vent tube105Air filter DESCRIPTION OF EMBODIMENTS

[0019] The embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the embodiments described herein are only to explain the present application, and are not intended to limit the present application.

[0020] The work platform hydraulic system and electric aerial work platform according to the present application are described below with reference to the drawings.

[0021] As shown in FIG. 1, in the electro-hydraulic drive system of an electric aerial work platform in the prior art, the substructure travelling hydraulic system supplies oil to the superstructure, that is, the substructure oil pump controls the output through the main valve (namely, multi-way valve), and transports the oil to the platform control valve through the relatively long pipeline around the boom drag chain, but there is a loss along the pipeline in the transportation of hydraulic oil through the long pipeline. In practical applications, for an electronically controlled leveling product, during the action of a main boom luffing cylinder, a leveling cylinder also needs to be linked and driven by oil supplied by the system. Under a small-load luffing condition, the oil pressure of the main boom luffing cylinder is generally low, usually about half of the maximum system pressure, while the oil pressure of the leveling oil remains at approximately two-thirds of the maximum system pressure. This will cause the main boom luffing with large flow and low pressure requirements to increase the entire system pressure by about 15% due to the participation of leveling, resulting in energy waste.

[0022] In view of this, the present application provides a new type of work platform hydraulic system, including: a platform cylinder hydraulic circuit; and a platform power unit 100, which is arranged on a work platform 200 and independently supplies oil to the platform cylinder hydraulic circuit.

[0023] Among them, the inventors of the present application deeply realized that, from the comparison of energy utilization rate, the efficiency of electric transmission and electric drive is much higher than that of hydraulic transmission and hydraulic drive. Based on the conventional technologies and the characteristics of aerial work platform transmission and drive, feasible paths for energy saving and consumption reduction include reducing energy losses in components and pipelines, and improving energy conversion and transmission efficiency. Effective measures include reducing the number of hydraulic control components and shortening the length of hydraulic pipelines, using high-efficiency electro-hydraulic components, and improving the system energy distribution efficiency and energy utilization efficiency.

[0024] To this end, the present application separately arranges a platform power unit 100 to independently supply oil to each platform cylinder, without drawing oil from the multi-way valve as shown in FIG. 1. That is, an electric transmission distributed arrangement and a hydraulic system combined with a hydraulic control valve and an actuator are adopted. After the distributed arrangement of the power unit is adopted, long pipelines for hydraulic oil delivery are no longer required, eliminating losses along the flow path, avoiding complex hydraulic pipeline connections, and reducing energy consumption in hydraulic transmission. In addition, since the platform oil source and the main boom luffing are independent of each other, increases in system pressure caused by leveling pressure are avoided, preventing energy waste and thereby improving energy efficiency.

[0025] FIG. 2 is a structural schematic diagram of an electric aerial work platform according to an embodiment of the present application. FIG. 3 is a hydraulic schematic diagram of the work platform hydraulic system according to an embodiment of the present application. As an example, the platform power unit 100 in FIG. 2 and FIG. 3 may include a motor pump 1 and a platform hydraulic oil tank 24 arranged on the work platform 200. The platform cylinder hydraulic circuit includes an oil circuit of a fly jib luffing cylinder, an oil circuit of a platform swing cylinder, and an oil circuit of a platform leveling cylinder. The motor pump 1 sucks hydraulic oil from the platform hydraulic oil tank 24 and pumps the hydraulic oil to the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder. In this way, the platform power unit 100 is arranged on the work platform 200, and the work platform hydraulic system is powered by the independent power unit, which is isolated from other low-pressure and high-flow actuators, reducing the overall energy consumption of the system, and avoiding the problems of long hydraulic oil pipelines, slow response to long-distance transmission, and large pressure loss.

[0026] For emergency use, the platform power unit 100 may further include an electric emergency pump 2 and / or a manual emergency pump 3. When the motor of the platform power unit 100 cannot be used due to a fault or power failure, electric emergency pump 2 or manual emergency pump 3 can be started in emergencies to ensure continuous oil supply for the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder, thereby ensuring the action and safety of the cylinders.

[0027] As shown in FIG. 3, the fly jib luffing, platform swing, and platform leveling actions of the electric aerial work platform are directly driven by the platform power unit 100. The hydraulic power and hydraulic system of the work platform 200 are shown in FIG. 3. The components that constitute a complete hydraulic control system include the hydraulic cylinders, the power unit, the control valves, the balance valves, the filters, the connecting pipelines, and the platform hydraulic oil tank 24.

[0028] Among them, the oil circuit of the platform leveling cylinder may include: a platform leveling cylinder 23 and a leveling proportional directional control valve 13; and a leveling compensator 12, in which a hydraulic control end of the leveling compensator 12 is connected to an outlet port of a leveling shuttle valve, and two inlet ports of the leveling shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the leveling proportional directional control valve 13 and the platform leveling cylinder 23.

[0029] The oil pressure required for the oil circuit of the platform leveling cylinder is relatively high and remains at approximately two-thirds of the maximum system pressure. When the driving cylinder extends, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the cap-end chamber of the platform leveling cylinder 23 after passing through the leveling compensator 12, the leveling proportional directional control valve 13, and the third balance valve 22. The oil in the rod-end chamber flows into the main oil return circuit after passing through the third balance valve 22 and the leveling proportional directional control valve 13, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0030] Similarly, when the driving cylinder retracts, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the rod-end chamber of the platform leveling cylinder 23 after passing through the leveling compensator 12, the leveling proportional directional control valve 13, and the third balance valve 22. The oil in the cap-end chamber of the cylinder flows into the main oil return circuit after passing through the third balance valve 22 and the leveling proportional directional control valve 13, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0031] The leveling compensator 12 ensures that the system flow and pressure are output to the platform leveling cylinder 23 as required by receiving a relatively high-pressure pilot signal transmitted from the leveling shuttle valve. The compensator valve port is open under normal conditions. When the platform leveling cylinder 23 works under load, the relatively high-pressure pilot oil in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit drives the compensator valve core to move, reducing the valve port opening. As the cylinder load increases, the valve port opening decreases, the supply flow decreases, and the piston rod extension speed decreases. Similarly, as the load decreases, the valve port opening increases, the supply flow increases, and the piston rod extension speed increases. As an example, the leveling compensator 12 can be a hydraulically controlled switch valve with continuously adjustable valve port opening.

[0032] In addition, the oil circuit of the platform swing cylinder may include: a platform swing cylinder 21 and a swing proportional directional control valve 11; and a fixed flow valve 10, arranged at the inlet port of the swing proportional directional control valve 11.

[0033] Specifically, when the platform swings to the left, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the left chamber of the platform swing cylinder 21 after passing through the fixed flow valve 10, the swing proportional directional control valve 11, and the second balance valve 20. The oil in the right chamber flows into the main oil return circuit after passing through the second balance valve 20 and the swing proportional directional control valve 11, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0034] When the platform swings to the right, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the right chamber of the platform swing cylinder 21 after passing through the fixed flow valve 10, the swing proportional directional control valve 11, and the second balance valve 20. The oil in the left chamber flows into the main oil return circuit after passing through the second balance valve 20 and the swing proportional directional control valve 11, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0035] The action of the platform leveling cylinder 21 should be smooth, so the fixed flow valve 10 is arranged to supply a stable flow to the leveling cylinder, ensuring that the leveling action is slow and smooth.

[0036] In addition, the oil circuit of the fly jib luffing cylinder may include: a fly jib luffing cylinder 19 and a luffing proportional directional control valve 9; and a luffing compensator 8, in which a hydraulic control end of the luffing compensator 8 is connected to an outlet port of a luffing shuttle valve, and two inlet ports of the luffing shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the luffing proportional directional control valve 9 and the fly jib luffing cylinder 19.

[0037] When the fly jib luffs upward, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the cap-end chamber of the fly jib luffing cylinder 19 after passing through the luffing compensator 8, the luffing proportional directional control valve 9, and the first balance valve 18. The oil in the rod-end chamber flows into the main oil return circuit after passing through the first balance valve 18 and the luffing proportional directional control valve 9, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0038] When the fly jib luffs downward, the platform power unit 100 outputs flow. The oil passes through the high-pressure filter 4, and the unloading valve 6 is energized and closed. The oil enters the rod-end chamber of the fly jib luffing cylinder 19 after passing through the luffing compensator 8, the luffing proportional directional control valve 9, and the first balance valve 18. The oil in the cap-end chamber flows into the main oil return circuit after passing through the first balance valve 18 and the luffing proportional directional control valve 9, and returns to the platform hydraulic oil tank 24 within the platform power unit 100.

[0039] The function of the luffing compensator 8 is substantially the same as that of the leveling compensator 12. The luffing compensator 8 ensures that the system flow and pressure are output to the luffing proportional directional control valve 9 as required by receiving a relatively high-pressure pilot signal in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit transmitted by the luffing shuttle valve. The compensator valve port is open under normal conditions, and when the fly jib luffing cylinder 19 works under load, the relatively high-pressure pilot oil in the rod-end chamber working oil circuit and the cap-end chamber working oil circuit drives the compensator valve core to move, reducing the valve port opening. As the cylinder load increases, the valve port opening decreases, the supply flow decreases, and the piston rod extension speed decreases. Similarly, as the load decreases, the valve port opening increases, the supply flow increases, and the piston rod extension speed increases.

[0040] In the embodiment of FIG. 3, the work platform hydraulic system may further include: a load sensing valve 7, in which a hydraulic control end of the load sensing valve 7 is respectively connected to rod-end chamber working oil circuits and cap-end chamber working oil circuits of the platform leveling cylinder 23, the fly jib luffing cylinder 19, and the platform swing cylinder 21 through a shuttle valve.

[0041] It can be seen that the hydraulic control end of the load sensing valve 7 obtains the highest pressure in each load working oil circuit. On this basis, pressure relief or oil replenishment is carried out according to load requirements, ensuring that the flow and pressure of the main oil inlet circuit are output as required by the system.

[0042] A main relief valve 5 is arranged in the hydraulic system of FIG. 3, and its relief pressure serves as the highest pressure of the system. When the relief pressure of the main relief valve is exceeded, the main overflow valve 5 is actuated to relieve pressure in the main oil inlet circuit. In addition, the working oil circuits of the fly jib luffing cylinder 19 and the platform leveling cylinder 23 are also arranged with a first relief valve 14, a second relief valve 15, a third relief valve 16, and a fourth relief valve 17 for overpressure relief to ensure the safety of the actuators.

[0043] In addition, because the platform power unit 100 consists of the platform hydraulic oil tank 24 and the motor pump 1, the platform power unit 100 is arranged on the work platform 200. When a leveling action is performed, the hydraulic oil tank appears in three states: tilted, horizontal, and inverted. If a conventional oil tank is used, when the oil tank is tilted or inverted, a problem of oil leakage through the air filter 105 may occur.

[0044] To solve this problem, the present application provides a specially designed internal structure for the hydraulic oil tank. As shown in FIG. 4, an exhaust connector 103 is arranged in the platform hydraulic oil tank 24 in this embodiment, and the exhaust connector 103 is connected to a vent tube 104, and the vent tube 104 extends out of the platform hydraulic oil tank 24. The air in the oil tank can be discharged or replenished in time through the exhaust connector 103 and the vent tube 104.

[0045] However, when the position of the oil tank is uncertain, it is necessary to ensure that the exhaust connector 103 is always in the air chamber in the oil tank so that the oil tank can breathe smoothly. Because the oil tank may be inverted, it is impossible to fix the exhaust connector 103 on the inner wall of the oil tank or arrange it in the center. These fixing methods are not feasible as they may easily cause the exhaust connector 103 to be submerged in oil, preventing the oil tank from breathing.

[0046] In particular, the exhaust connector 103 shown in FIG. 4 is connected to a float 102 for floating on the liquid surface, and the float 102 includes a hollow cavity and a gravity block 101 arranged inside the hollow cavity. Under the action of the gravity block 101 that can move freely in the cavity, the float 102 can always float on the liquid surface of the oil tank regardless of the position of the oil tank, as shown in FIG. 5 and FIG. 6. The float 102 can be a sphere as shown in the figures, a square box, or the like, and the gravity block 101 can be a metal sphere, a square metal block, or the like. The shape is not limited. With such an arrangement, the problem of oil leakage in the oil tank air filter when the platform is tilted or inverted can be solved.

[0047] An extended end of the vent tube 104 may also be arranged with the air filter 105 to prevent external contaminants from entering the oil tank. The function of the vent tube 104 is to connect the exhaust connector 103 with the air filter 105. Among them, the gravity block 101, the float 102, and the exhaust connector 103 can be separate bodies assembled as a whole, or they can be an integrated structure. The purpose is to enable the exhaust port of the exhaust connector 103 to remain in the air within the oil tank body outside the hydraulic oil level, regardless of the posture of the platform hydraulic oil tank 24. When the platform power unit 100 works and the oil in the oil tank decreases, the outside air can enter the oil tank through the air filter 105, the vent tube 104, and the exhaust connector 103; when the oil in the platform hydraulic oil tank 24 increases, the air inside the oil tank is discharged from the oil tank through the exhaust connector 103, the vent tube 104, and the air filter 105.

[0048] The above intake and exhaust design of the platform hydraulic oil tank 24 ensures smooth air intake and exhaust of the oil tank; it also ensures that, regardless of the posture or angle of the platform, the hydraulic oil will not leak out through the air filter 105.

[0049] The above work platform hydraulic system can be applied to various aerial work platforms, especially electric aerial work platforms, which is more energy-saving and consumption-reducing, and simplifies the layout of hydraulic pipelines.

[0050] When the above independent oil supply work platform hydraulic system is adopted, other actuators of the electric aerial work platform, such as each main boom working circuit of the main boom, can be supplied with oil through the substructure oil pump (not shown), and the substructure oil pump and the platform power unit 100 on the work platform 200 are arranged independently and distributedly.

[0051] By designing distributed hydraulic power and control for the work platform, the work platform hydraulic system is separated from other action hydraulic systems of the electric aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency. The intake and exhaust design of the hydraulic oil tank can ensure smooth air intake and exhaust of the oil tank; it can also ensure that, regardless of the posture or angle of the platform, the hydraulic oil will not leak out through the air filter.

[0052] In summary, in the work platform hydraulic system of the present application and the electric aerial work platform using the hydraulic system, distributed hydraulic power and control for the work platform are used to replace the centralized long-distance oil supply in the prior art, which avoids complex hydraulic pipeline connections, reduces hydraulic transmission energy consumption, and achieves long-distance energy transmission of the aerial work platform actuator, thereby improving energy efficiency. The distributed hydraulic power and control for the work platform separate the platform hydraulic system from other action hydraulic systems of the aerial work platform. When small-flow and high-pressure platform actions are performed simultaneously with large-flow and low-pressure actions, pressure redundancy and waste can be avoided, thereby improving energy efficiency.

[0053] In the description of the present application, it should be understood that the terms "first" and "second" are used merely for illustrative purposes and shall not be construed as indicating or implying relative importance or as implicitly specifying the number of technical features referred to. To this end, the features defined with the terms "first" and "second" may explicitly or implicitly include at least one of the features. In the context of the present application, unless otherwise specifically defined, "multiple" means at least two, for example, two or three.

[0054] In the present application, unless otherwise expressly specified and defined, the terms "mount", "be connected to", "be connected with", "fix", and so forth shall be interpreted in a broad sense. For example, the connection can be fixed connection, detachable connection, integrated connection, mechanical connection, electrical connection, connection capable of communicating with each other, direct connection, indirect connection through intermediate media, connection between two components or interaction between two components, unless otherwise specifically defined. For those of ordinary skill in the art, the specific meaning of the preceding terms in the present application can be understood according to the specific situation.

[0055] In the description of the specification, descriptions with reference to the terms "an embodiment", "some embodiments", "example", "specific example", or "some examples" mean that specific features, structures, materials, or characteristics described in combination with the embodiment or example are contained in at least an embodiment or example of the present application. In the specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Furthermore, the technicians in this field may combine different embodiments or examples described in the specification and features of different embodiments or examples without contradiction.

[0056] Although the embodiment of the present application has been shown and described above, it can be understood that the above embodiment is exemplary and cannot be understood as a limitation on the present application. The changes, modifications, replacements, and improvements can be made to the above embodiment within the scope of the present application for ordinary persons skilled in the art.

Examples

Embodiment Construction

[0019]The embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the embodiments described herein are only to explain the present application, and are not intended to limit the present application.

[0020]The work platform hydraulic system and electric aerial work platform according to the present application are described below with reference to the drawings.

[0021]As shown in FIG. 1, in the electro-hydraulic drive system of an electric aerial work platform in the prior art, the substructure travelling hydraulic system supplies oil to the superstructure, that is, the substructure oil pump controls the output through the main valve (namely, multi-way valve), and transports the oil to the platform control valve through the relatively long pipeline around the boom drag chain, but there is a loss along the pipeline in the transportation of hydraulic oil through the long pipeline. In practical applications, for ...

Claims

1. A work platform hydraulic system, comprising: a platform cylinder hydraulic circuit, comprising an oil circuit of a fly jib luffing cylinder, an oil circuit of a platform swing cylinder, and an oil circuit of a platform leveling cylinder; and a platform power unit (100), which is arranged on a work platform (200) and independently supplies oil to the platform cylinder hydraulic circuit, wherein the platform power unit (100) comprises a motor pump (1), and a platform hydraulic oil tank (24) arranged on the work platform (200), wherein the motor pump (1) sucks hydraulic oil from the platform hydraulic oil tank (24) and pumps the hydraulic oil to the oil circuit of the fly jib luffing cylinder, the oil circuit of the platform swing cylinder, and the oil circuit of the platform leveling cylinder.

2. The work platform hydraulic system according to claim 1, wherein the platform power unit (100) further comprises an electric emergency pump (2) and / or a manual emergency pump (3).

3. The work platform hydraulic system according to claim 1, wherein the oil circuit of the platform leveling cylinder comprises: a platform leveling cylinder (23) and a leveling proportional directional control valve (13); and a leveling compensator (12), wherein a hydraulic control end of the leveling compensator (12) is connected to an outlet port of a leveling shuttle valve, and two inlet ports of the leveling shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the leveling proportional directional control valve (13) and the platform leveling cylinder (23).

4. The work platform hydraulic system according to claim 3, wherein the oil circuit of the platform swing cylinder comprises: a platform swing cylinder (21) and a swing proportional directional control valve (11); and a fixed flow valve (10) arranged at an inlet port of the swing proportional directional control valve (11).

5. The work platform hydraulic system according to claim 4, wherein the oil circuit of the fly jib luffing cylinder comprises: a fly jib luffing cylinder (19) and a luffing proportional directional control valve (9); and a luffing compensator (8), wherein a hydraulic control end of the luffing compensator (8) is connected to an outlet port of a luffing shuttle valve, and two inlet ports of the luffing shuttle valve are respectively connected to a rod-end chamber working oil circuit and a cap-end chamber working oil circuit between the luffing proportional directional control valve (9) and the fly jib luffing cylinder (19).

6. The work platform hydraulic system according to claim 5, further comprising: a load sensing valve (7), wherein a hydraulic control end of the load sensing valve (7) is respectively connected through a shuttle valve to rod-end chamber working oil circuits and cap-end chamber working oil circuits of the platform leveling cylinder (23), the fly jib luffing cylinder (19), and the platform swing cylinder (21).

7. The work platform hydraulic system according to any one of claims 1-6, wherein an exhaust connector (103) is provided in the platform hydraulic oil tank (24), the exhaust connector (103) is connected to a vent tube (104), and the vent tube (104) extends out of the platform hydraulic oil tank (24).

8. The work platform hydraulic system according to claim 7, wherein the exhaust connector (103) is connected to a float (102) for floating on the liquid surface, and the float (102) comprises a hollow cavity and a gravity block (101) arranged inside the hollow cavity.

9. The work platform hydraulic system according to claim 7, wherein an air filter (105) is installed at an extended end of the vent tube (104).

10. An electric aerial work platform, comprising the work platform hydraulic system according to any one of claims 1-9.

11. The electric aerial work platform according to claim 10, wherein the electric aerial work platform further comprises a main boom working circuit and a substructure oil pump to supply oil to the main boom working circuit, and the substructure oil pump and the platform power unit (100) on the work platform (200) are arranged independently of each other in a distributed manner.

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