A hydraulic system in a hydrogen-electric hybrid container empty container handler

Abstract

The present invention belongs to the technical field of hydraulic control systems, and in particular relates to a hydraulic system in a hydrogen-electric "hybrid" container empty container stacker. In this hydraulic system, the lifting pump of the lifting system is in hydraulic pump mode, and the lifting cylinder performs a lifting action; when the lifting pump stops working, the lifting cylinder does not move; when the lifting pump is in hydraulic motor mode, the lifting valve group opens, and the lifting cylinder performs a descending action; when performing a steering action, the auxiliary hydraulic pump supplies oil to the hydraulic steering gear through the steering priority valve; when no steering action is performed and a lifting action is performed, the auxiliary hydraulic pump and the lifting pump jointly supply oil to the lifting cylinder. Therefore, since this hydraulic system cooperates with the lifting system and the auxiliary system, when the lifting cylinder descends, the potential energy drives the lifting pump to reverse, thereby realizing potential energy recovery. The lifting valve group is a switch valve. The auxiliary system realizes the normal operation of the entire machine, and has a small displacement, which reduces energy consumption and improves the working efficiency of the entire machine.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic control systems, and in particular relates to a hydraulic system in a hydrogen-electric hybrid container empty box stacker. Background Art

[0002] Empty container handlers are the mainstream equipment for stacking and transshipping empty containers, characterized by high site utilization and high speed. Currently, these machines are powered by either fuel or lithium batteries. In the port industry, due to the centralized nature of ship loading and unloading operations, there are requirements for equipment energy endurance. Fuel-powered handlers have a quick refueling time, meeting endurance requirements, but they present emissions challenges. Lithium battery-powered handlers are emission-free and energy-efficient, but they require a long recharge time, which falls short of high endurance requirements. To promote the application of hydrogen energy technology in the port industry, a hydrogen-electric hybrid empty container handler has been developed. This hybrid utilizes a combination of hydrogen fuel and lithium batteries as a hybrid power source. It can be fully refueled in 3-5 minutes, meeting endurance requirements, and produces only water, eliminating emissions. The operation of this hydrogen-electric hybrid empty container handler is controlled by a motor controller that drives a hydraulic system.

[0003] However, conventional hydraulic systems are throttle-controlled, using a proportional valve. The size of the valve opening determines the flow rate. Pressure loss across the proportional valve opening generates heat, heating the hydraulic system. Throttling, in turn, converts potential energy into heat. Traditional fuel-powered stackers utilize a single master hydraulic pump to supply oil for all movements. This results in a large total pump displacement and is non-reversible. During stacker operation, the inertial potential energy of the entire vehicle and the gravitational potential energy of the sling during lowering are dissipated through the heat generated by throttling, resulting in power loss in the hydraulic system. This reduces overall system efficiency, while the heat converted from this lost energy increases the temperature of the pressurized oil, deteriorating the oil and potentially causing hydraulic equipment failure. Summary of the Invention

[0004] (1) Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a hydraulic system for a hydrogen-electric "hybrid" container empty box forklift, thereby solving the technical problem that during the operation of the forklift, the inertial potential energy of the entire vehicle and the gravitational potential energy when the spreader is lowered are lost through heat, resulting in the inability to achieve effective energy utilization.

[0006] (2) Technical solution

[0007] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] The embodiment of the present invention provides a hydraulic system in a hydrogen-electric "hybrid" container empty container stacker, including a lifting system, an auxiliary system and a steering system; the lifting system includes a lifting pump, a lifting valve group and a lifting oil cylinder, and the lifting pump is connected to the lifting oil cylinder through the lifting valve group; the lifting pump is a two-way hydraulic pump. When the lifting pump is in the hydraulic pump working state, the lifting pump supplies oil to the lifting oil cylinder through the lifting valve group, and the lifting pump stops working, and the lifting valve group keeps the lifting oil cylinder in a fixed position after the lifting action; when the pump is in the hydraulic motor working state, the lifting valve group is opened, and the pressure oil in the lifting oil cylinder flows through the lifting valve group To the lifting pump; the auxiliary system includes an auxiliary hydraulic pump and a steering priority valve, the steering system includes a hydraulic steering gear, the auxiliary hydraulic pump is connected to the hydraulic steering gear and the electro-hydraulic proportional valve respectively through the steering priority valve, and the electro-hydraulic proportional valve is connected to the lifting valve group; when the hydraulic steering gear performs a steering action, the auxiliary hydraulic pump supplies oil to the hydraulic steering gear through the steering priority valve; when the hydraulic steering gear does not perform a steering action and the lifting cylinder performs a lifting action, the pressure oil generated by the auxiliary hydraulic pump enters the lifting valve group through the steering priority valve and the electro-hydraulic proportional valve in turn and merges with the pressure oil generated by the lifting pump to jointly supply oil to the lifting cylinder.

[0009] Furthermore, the lifting valve group includes a cartridge valve and a solenoid valve, the input oil ports of the cartridge valve and the solenoid valve are both connected to the lifting pump, and the output oil ports of the cartridge valve and the solenoid valve are both connected to the lifting cylinder; when the lifting cylinder is required to perform a lifting action, the pressure oil generated by the lifting pump opens the valve core of the cartridge valve and flows to the lifting cylinder through the cartridge valve; when the lifting cylinder is required to stop moving, the solenoid valve shall not be electrically closed, and the pressure oil in the lifting cylinder enters the spring chamber of the cartridge valve to push the valve core of the cartridge valve to close the cartridge valve, and the lifting cylinder 13 remains in a fixed position; when the lifting cylinder is required to perform a descending action, the solenoid valve is electrically conductive, and the pressure oil in the lifting cylinder opens the valve core of the cartridge valve and flows to the lifting pump through the cartridge valve. At the same time, the pressure oil in the spring chamber of the cartridge valve is unloaded through the return oil of the solenoid valve.

[0010] Furthermore, the lifting valve group also includes a converging one-way valve, the input oil port of the converging one-way valve is connected to the electro-hydraulic proportional valve, and the output oil port of the converging one-way valve is connected to the lifting cylinder, so that the pressure oil can only flow from the electro-hydraulic proportional valve to the lifting cylinder.

[0011] Furthermore, the lift valve group also includes a lift main overflow valve, which is arranged at the lift pump end and is used to unload oil to protect the lift pump when the lift valve group is overloaded.

[0012] Furthermore, the lifting valve group also includes a secondary relief valve, which is arranged at the end of the lifting cylinder to protect the lifting cylinder when an impact load occurs in the lifting valve group.

[0013] Furthermore, the lifting valve group also includes an emergency descent solenoid valve, which is used to allow the lifted heavy objects to fall slowly when the forklift fails.

[0014] Furthermore, it also includes a braking system, which includes a brake gear pump, a brake charging valve, a parking brake valve, a service brake valve and a brake accumulator. The brake gear pump is rigidly connected to the auxiliary hydraulic pump, and the brake gear pump can supply oil to the brake accumulator through the brake charging valve. The service brake valve is integrated on the brake charging valve, and the brake accumulator supplies oil to the service brake valve and the parking brake valve; the brake accumulator is set with a minimum charging pressure and a maximum charging pressure. When the pressure of the brake accumulator is less than the minimum charging pressure, the brake gear pump preferentially supplies oil to the brake accumulator through the brake charging valve; when the pressure of the brake accumulator reaches the maximum charging pressure, the pressure oil generated by the brake gear pump flows to the vehicle drive axle through the pressure relief port of the brake charging valve to flush and cool the vehicle drive axle; when the pressure of the brake accumulator is lower than the minimum charging pressure, the forklift cannot travel.

[0015] Furthermore, the braking system further includes an accumulator pressure switch, which is used to detect the pressure of the brake accumulator.

[0016] Furthermore, the lifting system also includes a lifting filter, which includes a one-way valve liquid bridge and a filter to ensure that the pressure oil passing through the lifting pump and the lifting valve group in both directions can be filtered.

[0017] Furthermore, the lifting system also includes a flow limiting valve, which is installed at the outlet of the lifting cylinder to ensure that the flow rate of pressurized oil flowing through the outlet of the lifting cylinder is not greater than a limited value; at the same time, the flow limiting valve can also prevent the oil pipe from bursting when the lifting cylinder is descending, causing the lifted heavy object to stall.

[0018] (3) Beneficial effects

[0019] The beneficial effects of the present invention are:

[0020] The hydraulic system of the hydrogen-electric hybrid container empty container stacker of the present invention comprises a lifting system and an auxiliary system. The lifting system comprises a lifting pump and a lifting valve assembly for driving the lifting cylinder, while the auxiliary system comprises an auxiliary hydraulic pump for supplying oil for other operations besides driving the lifting cylinder. The lifting pump is a bidirectional hydraulic pump that can be reversed for energy recovery. The potential energy of the lifting cylinder changes during the lifting process. When the lifting cylinder descends, the potential energy drives the lifting pump to reverse, which in turn drives the lifting motor 16 to generate electricity, thus recovering potential energy. The lithium battery then stores the recovered energy, extending the battery's endurance.

[0021] At the same time, the auxiliary hydraulic pump ensures the normal operation of the entire machine and ensures the safety of the entire machine. Compared with the main hydraulic pump in the traditional fuel stacker, the displacement of the auxiliary hydraulic pump is significantly smaller.

[0022] The present invention combines the lifting system with the auxiliary system, which, compared with the prior art, realizes energy recovery, reduces energy consumption, improves the working efficiency of the entire machine, and extends the service life of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the schematic diagram of the hydraulic system;

[0024] Figure 2 This is the schematic diagram of the lifting system;

[0025] Figure 3 Transmission system for lift motor and lift pump;

[0026] Figure 4 Auxiliary motor and auxiliary hydraulic pump drive system;

[0027] Figure 5 It is the transmission system of the auxiliary hydraulic pump and brake gear pump.

[0028] [Description of Reference Numerals]

[0029] 1: Lifting system; 11: Lifting pump; 12: Lifting valve group; 121: Cartridge valve; 122: Solenoid valve; 123: Combining check valve; 124: Lifting main relief valve; 125: Secondary relief valve; 126: Emergency lowering solenoid valve; 127: Pressure sensor; 13: Lifting cylinder; 14: Lifting filter; 141: Check valve bridge; 142: Filter; 15: Flow limiting valve; 16: Lifting motor; 17: Lifting coupling; 18: Lifting coupling bell housing;

[0030] 2: Auxiliary system; 21: Auxiliary hydraulic pump; 22: Steering priority valve; 23: Auxiliary motor; 24: Auxiliary motor coupling; 25: Auxiliary motor bell housing;

[0031] 3: Steering system; 31: Hydraulic steering gear;

[0032] 4: Electro-hydraulic proportional valve;

[0033] 5: Braking system; 51: Brake gear pump; 52: Brake filling valve; 53: Parking brake valve; 54: Brake accumulator; 55: Vehicle drive axle; 56: Accumulator pressure switch; 57: Radiator; 58: Filter. DETAILED DESCRIPTION

[0034] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0035] like Figure 1-5 As shown, the present invention provides a hydraulic system for a hydrogen-electric hybrid container empty container handler, such as Figure 1As shown, the vehicle comprises a lifting system 1, an auxiliary system 2, a steering system 3, and a braking system 5. The auxiliary system 2 can supply oil to the steering system 3, and the auxiliary system 2 can supply oil to the lifting system 1 through the electro-hydraulic proportional valve 4. The lifting system 1 includes a lifting pump 11, a lifting valve group 12, and a lifting cylinder 13. The lifting pump 11 is connected to the lifting cylinder 13 through the lifting valve group 12. The auxiliary system 2 includes an auxiliary hydraulic pump 21 and a steering priority valve 22. The steering system 3 includes a hydraulic steering gear 31. The auxiliary hydraulic pump 21 is connected to the hydraulic steering gear 31 and the electro-hydraulic proportional valve 4 respectively through the steering priority valve 22. The electro-hydraulic proportional valve 4 is connected to the lifting valve group 12.

[0036] The operation of the hydrogen-electric "hybrid" container empty container handler is powered by a hydrogen fuel cell and a lithium battery pack, which enables the electronic control system to drive the hydraulic system.

[0037] Specifically, the electronic control system includes a hoist mechanism electronic drive circuit, an auxiliary mechanism electronic drive circuit, and a DC bus. The hoist motor controller in the hoist mechanism electronic drive circuit controls the speed of the hoist motor 16, while the auxiliary motor controller in the auxiliary mechanism electronic drive circuit controls the speed of the auxiliary motor 23.

[0038] like Figure 3 As shown, the output shaft of the lifting motor 16 is connected to the input shaft of the lifting pump 11 through the lifting coupling 17, which is used to drive the lifting pump 11. The lifting pump 11 is rigidly connected to the lifting motor 16 through the lifting coupling bell 18 to ensure the coaxiality of the lifting motor 16 and the lifting pump 11.

[0039] like Figure 4 As shown, the output shaft of the auxiliary motor 23 is connected to the input shaft of the auxiliary hydraulic pump 21 through the auxiliary motor coupling 24, so as to drive the auxiliary hydraulic pump 21. The auxiliary hydraulic pump 21 is rigidly connected to the auxiliary motor 23 through the auxiliary motor bell 25 to ensure the coaxiality of the auxiliary motor 23 and the auxiliary hydraulic pump 21.

[0040] Lift pump 11 is a bidirectional hydraulic pump, operating in both hydraulic pump and hydraulic motor modes. Lift cylinder 13 drives the weight up and down, causing the weight's potential energy to change during the lifting process. When lifting cylinder 13 is required, lift pump 11 operates in hydraulic pump mode. Lift motor 16 rotates forward, driving lift pump 11 forward to generate pressurized oil. At this point, lift pump 11 acts as an energy source. Lift pump 11 supplies oil to lift cylinder 13 via lift valve assembly 12.

[0041] When the lifting cylinder 13 needs to stop moving, the lifting pump 11 stops working, and the lifting valve group 12 keeps the lifting cylinder 13 in a fixed position after the lifting action.

[0042] When the lift cylinder 13 needs to be lowered, the lift pump 11 operates as a hydraulic motor, outputting mechanical energy that drives the lift motor 16 to reverse and generate electricity. At this point, the lift pump 11 is an actuator and cannot supply power to the hydraulic system, so the auxiliary system 2 must be configured to provide power to the hydraulic system. At this point, the lift valve block 12 opens, allowing the pressurized oil in the lift cylinder 13 to flow through it to the lift pump 11.

[0043] Specifically, if Figure 2 As shown, the lift valve assembly 12 includes a cartridge valve 121 and a solenoid valve 122. Both the cartridge valve 121 and the solenoid valve 122 are on-off valves. Their oil inputs are connected to the lift pump 11, while their oil outputs are connected to the lift cylinder 13. This allows the cartridge valve 121 and the solenoid valve 122 to jointly control the oil flow between the lift pump 11 and the lift cylinder 13. The pressurized oil generated by the lift pump 11 is fully capable of driving the lift cylinder 13 for lift via the lift valve assembly 12.

[0044] The lifting valve group 12 also includes a converging one-way valve 123, the input oil port of the converging one-way valve 123 is connected to the electro-hydraulic proportional valve 4, and the output oil port of the converging one-way valve 123 is connected to the lifting cylinder 13, so that the pressure oil can only flow from the electro-hydraulic proportional valve 4 to the lifting cylinder 13 and cannot flow back to the electro-hydraulic proportional valve 4.

[0045] Working principle of lifting system 1

[0046] When the heavy object rises and the lifting cylinder 13 needs to perform the lifting action, the lifting motor controller controls the lifting motor 16 to rotate forward, driving the lifting pump 11 to rotate forward to generate pressure oil. The lifting pump 11 is in hydraulic pump working condition. At this time, in the lifting valve group 12, the pressure oil generated by the lifting pump 11 overcomes the spring force of the cartridge valve 121, opens the valve core of the cartridge valve 121, and makes the oil circuit between the lifting pump 11 and the lifting cylinder 13 conductive. The pressure oil generated by the lifting pump 11 flows to the lifting cylinder 13, pushing the lifting cylinder 13 to rise.

[0047] At the same time, due to the influence of the self-priming ability of the lifting pump 11, in order to prevent untimely oil suction, which causes wear of the lifting pump 11, the speed of the lifting pump 11 is limited, and its speed is ≤ the maximum speed limit of the hydraulic pump working condition of the lifting pump 11, resulting in the flow rate of the output pressure oil cannot meet the flow rate requirements required for the speed of the lifting action. Therefore, the auxiliary system 2 will generate a path of pressure oil through the electro-hydraulic proportional valve 4 into the lifting valve group 12 and merge with the pressure oil generated by the lifting pump 11 through the merging one-way valve 123, and jointly supply oil to the lifting cylinder 13 to push the heavy object up.

[0048] When the heavy object stops and the lifting cylinder 13 needs to stop moving, the solenoid valve 122 is de-energized, and the pressure oil in the lifting cylinder 13 enters the spring chamber of the cartridge valve 121, pushing the valve core of the cartridge valve 121 to close the cartridge valve 121, disconnecting the oil circuit between the lifting pump 11 and the lifting cylinder 13, and keeping the lifting cylinder 13 in a fixed position.

[0049] When the heavy object is lowered and the lifting cylinder 13 needs to perform a lowering action, the lifting pump 11 is in the hydraulic motor working state, the solenoid valve 122 is electrically conductive, and the pressure oil in the spring chamber of the cartridge valve 121 returns to the oil chamber through the solenoid valve 122 to unload the load. The pressure oil in the lifting cylinder 13 overcomes the spring force of the cartridge valve 121, opens the valve core of the cartridge valve 121, and makes the circuit between the lifting cylinder 13 and the lifting pump 11 conductive. The pressure oil in the lifting cylinder 13 flows to the lifting pump 11 through the cartridge valve 121, pushing the lifting pump 11 to reverse, that is, the potential energy drives the lifting pump 11, and then drives the lifting motor 16 to reverse and generate electricity. At this time, the lifting motor controller acts as a rectifier to convert the AC power generated by the lifting motor 16 into DC current and output it to the DC bus, so that the voltage of the DC bus increases and is higher than the voltage of the lithium battery. At this time, the electrical energy generated by the current will enter the lithium battery for storage, realizing potential energy recovery. At this time, since the lifting pump 11 does not have the self-priming problem, its maximum speed can reach the maximum speed of the hydraulic motor of the lifting pump 11 in the working condition.

[0050] like Figure 2 As shown, the lift valve group 12 also includes a lift main relief valve 124, a secondary relief valve 125, an emergency lowering solenoid valve 126 and a pressure sensor 127. The lift main relief valve 124 is arranged at the end of the lift pump 11 to unload oil and protect the lift pump 11 when the lift valve group 12 is overloaded.

[0051] The secondary relief valve 125 is provided at the end of the lifting cylinder 13 to protect the lifting cylinder 13 when an impact load occurs to the lifting valve assembly 12 .

[0052] The emergency descent solenoid valve 126 is used to allow the lifted objects to slowly drop down when the stacker fails.

[0053] The pressure sensor 127 is used to detect the pressure of the lifting system 1 in real time, which can be used for lifting weight calculation. When the lifting system 1 is over-pressurized, the lifting motor controller is controlled to stop the lifting motor 16 to protect the lifting pump 11.

[0054] In addition, if Figure 1 As shown, the lifting system 1 further includes a lifting filter 14 and a flow limiting valve 15. The lifting filter 14 includes a one-way valve liquid bridge 141 and a filter 142 to ensure that the pressure oil passing through the lifting pump 11 and the lifting valve group 12 in both directions can be filtered.

[0055] The flow limiting valve 15 is installed at the outlet of the lifting cylinder 13 to ensure that the flow rate of the pressurized oil flowing through the outlet of the lifting cylinder 13 is not greater than a limited value.

[0056] At the same time, the flow limiting valve 15 can also prevent the oil pipe from bursting when the lifting cylinder 13 is descending, causing the lifted heavy object to stall.

[0057] How Assistance System 2 works

[0058] Because steering is a top priority for equipment safety, the steering system 3 must remain in a constant standby state. The auxiliary motor 23 maintains a constant rotational speed, ensuring that the auxiliary hydraulic pump 21 is constantly producing pressurized oil. Therefore, when the hydraulic steering gear 31 is required to perform a steering action, the auxiliary hydraulic pump 21 prioritizes oil supply to the hydraulic steering gear 31 through the steering priority valve 22.

[0059] When the hydraulic steering gear 31 is not needed for steering and the lifting cylinder 13 is needed for lifting, the pressure oil generated by the auxiliary hydraulic pump 21 enters the lifting valve group 12 through the steering priority valve 22 and the electro-hydraulic proportional valve 4 in turn and merges with the pressure oil generated by the lifting pump 11 to jointly supply oil to the lifting cylinder 13.

[0060] like Figure 1 As shown, the braking system 5 includes a brake gear pump 51, a brake filling valve 52, a parking brake valve 53, a service brake valve, a brake accumulator 54 and an accumulator pressure switch 56. The service brake valve is integrated into the brake filling valve 52. The parking brake valve 53 and the service brake valve control the parking brake and service brake of the entire vehicle. The brake gear pump 51 can supply oil to the brake accumulator 54 through the brake filling valve 52, and the brake accumulator 54 supplies oil to the service brake valve and the parking brake valve 53. Because braking also involves the safety of the equipment and has the highest priority like steering, in order to ensure the safety of the equipment, the braking system 5 also needs to be in standby mode at all times so that when the vehicle loses power, it still has braking capability. Therefore, the brake gear pump 51 needs to be kept in working condition at all times. Therefore, Figure 5 As shown, the auxiliary hydraulic pump 21 is set to a through-shaft form and is rigidly connected to the through-shaft of the auxiliary hydraulic pump 21. In this way, the tail of the auxiliary hydraulic pump 21 can be directly connected to the brake gear pump 51, so that the input shaft of the auxiliary hydraulic pump 21 is directly connected to the input shaft of the brake gear pump 51. The auxiliary motor 23 can drive the auxiliary hydraulic pump 21 and the brake gear pump 51 at the same time, so that the brake accumulator 54 always stores a certain amount of pressurized oil to ensure vehicle safety.

[0061] The brake accumulator 54 is set with a minimum filling pressure and a maximum filling pressure. The accumulator pressure switch 56 is used to detect the pressure of the brake accumulator 54. When the pressure of the brake accumulator 54 is lower than the minimum filling pressure, the brake filling valve 52 opens the oil circuit between the brake gear pump 51 and the brake accumulator 54, and the brake gear pump 51 preferentially supplies oil to the brake accumulator 54 through the brake filling valve 52.

[0062] When the pressure of the brake accumulator 54 reaches the maximum filling pressure, the brake filling valve 52 closes the oil circuit between the brake gear pump 51 and the brake accumulator 54, and the pressure oil generated by the brake gear pump 51 flows to the vehicle drive axle 55 through the pressure relief port of the brake filling valve 52 to take away the heat generated by the vehicle drive axle 55 due to braking, flush and cool the vehicle drive axle 55, and return to the oil tank after cooling and filtering through the radiator 57 and the filter 58.

[0063] When the pressure of the brake accumulator 54 is lower than the minimum filling pressure, it is considered that the brake pressure is insufficient and the stacker cannot be moved.

[0064] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0065] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0066] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0067] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0068] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A hydraulic system in a hydrogen-electric hybrid container empty container handler, characterized in that: It includes a lifting system (1), an auxiliary system (2) and a steering system (3); The lifting system (1) includes a lifting pump (11), a lifting valve group (12) and a lifting cylinder (13), wherein the lifting pump (11) is connected to the lifting cylinder (13) through the lifting valve group (12); The lifting pump (11) is a bidirectional hydraulic pump. When the lifting pump (11) is in the hydraulic pump working state, the lifting pump (11) supplies oil to the lifting cylinder (13) through the lifting valve group (12). The lifting pump (11) stops working, and the lifting valve group (12) keeps the lifting cylinder (13) in a fixed position after the lifting action. When the lifting pump (11) is in the hydraulic motor working state, the lifting valve group (12) is opened, and the pressure oil in the lifting cylinder (13) flows to the lifting pump (11) through the lifting valve group (12). The auxiliary system (2) includes an auxiliary hydraulic pump (21) and a steering priority valve (22), and the steering system (3) includes a hydraulic steering gear (31). The auxiliary hydraulic pump (21) is connected to the hydraulic steering gear (31) and the electro-hydraulic proportional valve (4) through the steering priority valve (22), and the electro-hydraulic proportional valve (4) is connected to the lifting valve group (12). When the hydraulic steering gear (31) performs a steering action, the auxiliary hydraulic pump (21) supplies oil to the hydraulic steering gear (31) through the steering priority valve (22); when the hydraulic steering gear (31) does not perform a steering action and the lifting cylinder (13) performs a lifting action, the pressure oil generated by the auxiliary hydraulic pump (21) sequentially passes through the steering priority valve (22) and the electro-hydraulic proportional valve (4) into the lifting valve group (12) and merges with the pressure oil generated by the lifting pump (11) to supply oil to the lifting cylinder (13); The lifting valve group (12) includes a cartridge valve (121) and a solenoid valve (122), the oil input ports of the cartridge valve (121) and the solenoid valve (122) are both connected to the lifting pump (11), and the oil output ports of the cartridge valve (121) and the solenoid valve (122) are both connected to the lifting cylinder (13); When the lifting cylinder (13) is required to perform a lifting action, the pressure oil generated by the lifting pump (11) opens the valve core of the cartridge valve (121) and flows to the lifting cylinder (13) through the cartridge valve (121); When the lifting cylinder (13) needs to stop moving, the solenoid valve (122) must not be electrically closed, and the pressure oil in the lifting cylinder (13) enters the spring chamber of the cartridge valve (121) to push the valve core of the cartridge valve (121) to close the cartridge valve (121), and the lifting cylinder (13) remains in a fixed position; When the lifting cylinder (13) is required to perform a descending action, the solenoid valve (122) is electrically connected, and the pressure oil in the lifting cylinder (13) opens the valve core of the cartridge valve (121) and flows to the lifting pump (11) through the cartridge valve (121). At the same time, the pressure oil in the spring chamber of the cartridge valve (121) returns to the solenoid valve (122) to unload the oil. The lifting valve group (12) further includes a merging check valve (123), the input oil port of the merging check valve (123) is connected to the electro-hydraulic proportional valve (4), and the output oil port of the merging check valve (123) is connected to the lifting cylinder (13), so that the pressure oil can only flow from the electro-hydraulic proportional valve (4) to the lifting cylinder (13); The lifting valve group (12) further includes a lifting main overflow valve (124), which is arranged at the end of the lifting pump (11) and is used to unload oil to protect the lifting pump (11) when the lifting valve group (12) is overloaded; The lifting valve assembly (12) further includes a secondary relief valve (125), which is arranged at the end of the lifting cylinder (13) and is used to protect the lifting cylinder (13) when an impact load occurs to the lifting valve assembly (12); The lifting valve assembly (12) further comprises an emergency lowering solenoid valve (126) for allowing the lifted heavy object to slowly fall down when the stacker fails.

2. The hydraulic system of the hydrogen-electric hybrid container empty container handler according to claim 1 is characterized in that: The vehicle further comprises a brake system (5), wherein the brake system (5) comprises a brake gear pump (51), a brake filling valve (52), a parking brake valve (53), a service brake valve and a brake accumulator (54), wherein the brake gear pump (51) is rigidly connected to the auxiliary hydraulic pump (21), the brake gear pump (51) can supply oil to the brake accumulator (54) through the brake filling valve (52), the service brake valve is integrated on the brake filling valve (52), and the brake accumulator (54) supplies oil to the service brake valve and the parking brake valve (53); The brake accumulator (54) is set with a minimum filling pressure and a maximum filling pressure. When the pressure of the brake accumulator (54) is less than the minimum filling pressure, the brake gear pump (51) preferentially supplies oil to the brake accumulator (54) through the brake filling valve (52); When the pressure of the brake accumulator (54) reaches the maximum filling pressure, the pressure oil generated by the brake gear pump (51) flows to the vehicle drive axle (55) through the pressure relief port of the brake filling valve (52) to flush and cool the vehicle drive axle (55); When the pressure of the brake accumulator (54) is lower than the minimum charging pressure, the stacker cannot travel.

3. The hydraulic system of the hydrogen-electric hybrid container empty container handler according to claim 2 is characterized in that: The brake system (5) further comprises an accumulator pressure switch (56), which is used to detect the pressure of the brake accumulator (54).

4. The hydraulic system of the hydrogen-electric hybrid container empty container handler according to claim 1 is characterized in that: The lifting system (1) further comprises a lifting filter (14), which comprises a one-way valve liquid bridge (141) and a filter (142) to ensure that the pressure oil passing in both directions between the lifting pump (11) and the lifting valve group (12) is filtered.

5. The hydraulic system of the hydrogen-electric hybrid container empty container handler according to claim 1 is characterized in that: The lifting system (1) further includes a flow limiting valve (15), which is installed at the outlet of the lifting cylinder (13) to ensure that the flow rate of the pressure oil flowing through the outlet of the lifting cylinder (13) is not greater than a limited value; At the same time, the flow limiting valve (15) also prevents the oil pipe from bursting when the lifting cylinder (13) performs a descending action, causing the lifted weight to stall.

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