Hydraulic system in hydrogen-electricity hybrid empty container stacking machine

Abstract

The invention belongs to the technical field of hydraulic control systems, and particularly relates to a hydraulic system in a hydrogen-electricity hybrid empty container stacking machine. When a lifting pump of a lifting system in the hydraulic system is in a hydraulic pump working condition, a lifting oil cylinder performs a lifting action; when the lifting pump stops acting, the lifting oil cylinder does not move; when the lifting pump is in a hydraulic motor working condition, the lifting valve group is opened, and the lifting oil cylinder descends; during steering action, the auxiliary hydraulic pump supplies oil to the hydraulic steering gear through the steering priority valve; and when the steering action is not performed and the lifting action is performed, the auxiliary hydraulic pump and the lifting pump supply oil to the lifting oil cylinder together. Therefore, according to the hydraulic system, due to the fact that the lifting system is matched with the auxiliary system, when the lifting oil cylinder descends, potential energy drives the lifting pump to rotate reversely, and potential energy recycling is achieved. And the lifting valve group is a switch valve. The auxiliary system realizes the normal work of the whole machine, the displacement is small, the energy consumption is reduced, and the working efficiency of the whole machine is improved.

Description

Technical Field

[0001] The 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 handler is the mainstream equipment for stacking and transshipping empty containers, with the characteristics of high site utilization and high speed. At present, the equipment uses fuel or lithium batteries as the power source. In the port industry, due to the concentrated loading and unloading operations, there are requirements for the endurance of the equipment energy. The fuel-powered stacker has a short refueling time, which meets the endurance requirements, but there are emission problems. The lithium battery stacker has no emissions, is energy-saving and environmentally friendly, but the charging time is long and does not meet the requirements of high endurance. In order to promote the application of hydrogen energy technology in the port industry, a hydrogen-electric "hybrid" empty container handler that uses hydrogen fuel and lithium batteries as a hybrid power source has come into being. It can be filled with hydrogen in 3-5 minutes, meeting the endurance requirements, and only produces water, without emission problems. The operation of the hydrogen-electric "hybrid" empty container handler is completed by the motor controller controlling the motor drive hydraulic system.

[0003] However, conventional hydraulic systems are throttling controlled, and the valve that controls throttling is a proportional valve. The size of the valve opening determines the flow rate. There is pressure loss before and after the proportional valve port, which will generate heat energy, causing the hydraulic system to heat up, thereby converting potential energy into heat energy through throttling. Traditional fuel stackers use a total hydraulic pump to meet the oil supply for all actions, so the total hydraulic pump displacement is large and cannot be reversed. During the operation of the stacker, the inertial potential energy of the entire vehicle and the gravitational potential energy when the hoist descends will be lost through the heat generated after throttling, causing power loss in the hydraulic system. On the one hand, the overall efficiency of the system is reduced, and on the other hand, the heat energy converted from this part of the lost energy will increase the temperature of the pressure oil, deteriorate the oil, and cause the hydraulic equipment to malfunction. 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 in 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 whole vehicle and the gravitational potential energy when the sling is lowered are lost through heat, resulting in the inability to achieve effective energy utilization.

[0006] (II) Technical solution

[0007] In order to achieve the above object, 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 box forklift, 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 cylinder, and the lifting pump is connected to the lifting 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 cylinder through the lifting valve group, the lifting pump stops working, and the lifting valve group keeps the lifting cylinder in a fixed position after the lifting action; when the lifting pump is in the hydraulic motor working state, the lifting valve group is opened, and the pressure oil in the lifting 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 supply oil to the lifting cylinder together.

[0009] Furthermore, the lifting valve group includes a cartridge valve and a solenoid valve, the oil input ports of the cartridge valve and the solenoid valve are both connected to the lifting pump, and the oil output 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 must 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 merging one-way valve, the input oil port of the merging one-way valve is connected to the electro-hydraulic proportional valve, and the output oil port of the merging 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 filling 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 filling valve. The service brake valve is integrated on the brake filling 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 filling pressure and a maximum filling pressure. When the pressure of the brake accumulator is less than the minimum filling pressure, the brake gear pump preferentially supplies oil to the brake accumulator through the brake filling valve; when the pressure of the brake accumulator reaches the maximum filling pressure, the pressure oil generated by the brake gear pump flows to the vehicle drive axle through the pressure relief port of the brake filling valve to flush and cool the vehicle drive axle; when the pressure of the brake accumulator is lower than the minimum filling pressure, the forklift cannot travel.

[0015] Furthermore, the brake system further comprises an accumulator pressure switch, and the accumulator pressure switch 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 pressure oil flow rate 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] (III) Beneficial effects

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

[0020] The hydraulic system in a hydrogen-electric "hybrid" container empty box stacker of the present invention is provided with a lifting system and an auxiliary system, wherein a lifting pump and a lifting valve group for driving a lifting cylinder are provided in the lifting system, and an auxiliary hydraulic pump for supplying oil for other actions except driving the lifting cylinder is provided in the auxiliary system. The lifting pump is a bidirectional hydraulic pump that can be reversed for energy recovery. During the lifting process of the lifting cylinder, the potential energy changes. When the lifting cylinder descends, the potential energy drives the lifting pump to reverse, and the lifting pump then drives the lifting motor 16 to generate electricity to achieve potential energy recovery. The lithium battery then stores the recovered energy, thereby extending the endurance.

[0021] At the same time, the auxiliary hydraulic pump realizes the normal operation of the whole machine and ensures the safety of the whole machine operation. 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 cooperates the lifting system with the auxiliary system, and compared with the prior art, it realizes energy recovery, reduces energy consumption, improves the working efficiency of the whole machine, and prolongs 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 lifting motor and lifting pump;

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

[0027] Figure 5 It is the transmission system of 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: Converging 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 liquid bridge; 142: Filter; 15: Flow limiting valve; 16: Lifting motor; 17: Lifting coupling; 18: Lifting coupling bell;

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

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

[0032] 4: Electro-hydraulic proportional valve;

[0033] 5: Braking system; 51: Braking gear pump; 52: Braking filling valve; 53: Parking brake valve; 54: Braking 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 modes in conjunction with the accompanying drawings.

[0035] like Figure 1-5 As shown, the present invention provides a hydraulic system in a hydrogen-electric "hybrid" container empty box forklift, such as Figure 1As shown, it includes 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 through the steering priority valve 22, and 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 electric control system includes a lifting mechanism electric control drive circuit, an auxiliary mechanism electric control drive circuit and a DC bus. The lifting motor controller in the lifting mechanism electric control drive circuit controls the speed of the lifting motor 16, and the auxiliary motor controller in the auxiliary mechanism electric control 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, so as 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] The lifting pump 11 is a bidirectional hydraulic pump, corresponding to the hydraulic pump working condition and the hydraulic motor working condition respectively. The lifting cylinder 13 drives the weight to rise and fall. During the lifting process, the potential energy of the weight changes. When the lifting cylinder 13 is required to perform a lifting action, the lifting pump 11 is in the hydraulic pump working condition, and the lifting motor 16 drives the lifting pump 11 to rotate forward to generate pressure oil. At this time, the lifting pump 11 is an energy device. The lifting pump 11 supplies oil to the lifting cylinder 13 through the lifting valve group 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 at a fixed position after the lifting action.

[0042] When the lifting cylinder 13 is required to descend, the lifting pump 11 is in hydraulic motor mode, and the lifting pump 11 outputs mechanical energy to drive the lifting motor 16 to reverse and generate electricity. At this time, the lifting pump 11 is an actuator and cannot supply energy to the hydraulic system, so the auxiliary system 2 is set to supply energy to the hydraulic system. At this time, 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.

[0043] Specifically, Figure 2 As shown, the lift valve group 12 includes a cartridge valve 121 and a solenoid valve 122, both of which are switch valves, and the input oil ports of the cartridge valve 121 and the solenoid valve 122 are connected to the lift pump 11, and the output oil ports of the cartridge valve 121 and the solenoid valve 122 are connected to the lift cylinder 13, so that the cartridge valve 121 and the solenoid valve 122 jointly control the on-off of the oil circuit between the lift pump 11 and the lift cylinder 13. The pressure oil generated by the lift pump 11 can completely drive the lift cylinder 13 to lift through the lift valve group 12.

[0044] The lifting valve group 12 also includes a merging one-way valve 123, the input oil port of the merging one-way valve 123 is connected to the electro-hydraulic proportional valve 4, and the output oil port of the merging 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 a 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 to make the oil circuit between the lifting pump 11 and the lifting cylinder 13 conductive, and 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 leads to wear of the lifting pump 11, the rotation speed of the lifting pump 11 is limited, and its rotation speed is ≤ the maximum speed limit of the hydraulic pump operating condition of the lifting pump 11, resulting in the flow rate of the output pressure oil cannot meet the flow rate 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 through the merging check valve 123 and merge with the pressure oil generated by the lifting pump 11, and together 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 hydraulic motor working mode, the solenoid valve 122 is electrically conductive, and the pressure oil in the spring chamber of the cartridge valve 121 is unloaded through the return oil of the solenoid valve 122. The pressure oil in the lifting cylinder 13 overcomes the spring force of the cartridge valve 121, and the valve core of the cartridge valve 121 is opened to make 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 electric energy generated by the current will enter the lithium battery for storage, realizing the recovery of potential energy. At this time, since the lifting pump 11 does not have a 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 disposed 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 heavy 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 pressure 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 involves the safety of the equipment and has the highest priority, in order to ensure the safety of the equipment, the steering system 3 must always be in a standby state, and the auxiliary motor 23 always maintains a certain speed so that the auxiliary hydraulic pump 21 is always in a state of generating pressurized oil. Therefore, when the hydraulic steering gear 31 is required to perform a steering action, the auxiliary hydraulic pump 21 supplies oil to the hydraulic steering gear 31 first through the steering priority valve 22.

[0059] When the hydraulic steering gear 31 is not needed to perform steering action and the lifting cylinder 13 is needed to perform lifting action, 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 brake 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 on the brake filling valve 52. The parking brake valve 53 and the service brake valve control the parking brake and service brake of the whole 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 brake 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 state at all times. Therefore, Figure 5 As shown, the auxiliary hydraulic pump 21 is arranged in a through-shaft form and is rigidly connected to the auxiliary hydraulic pump 21 through-shaft. 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, and 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 less than the minimum filling pressure, the brake filling valve 52 connects the oil circuit between the brake gear pump 51 and the brake accumulator 54, and the brake gear pump 51 supplies oil to the brake accumulator 54 through the brake filling valve 52 first.

[0062] When the pressure in 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 the pressure oil is cooled and filtered 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 driven.

[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 as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be 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. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0067] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations 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 the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0068] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of 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 stacker, characterized in that: It comprises a lifting system (1), an auxiliary system (2) and a steering system (3); The lifting system (1) comprises 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) via the lifting valve group (12); The lifting pump (11) is a bidirectional hydraulic pump. When the lifting pump (11) is in a 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 a hydraulic motor working state, the lifting valve group (12) opens, 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) comprises an auxiliary hydraulic pump (21) and a steering priority valve (22), the steering system (3) comprises a hydraulic steering gear (31), the auxiliary hydraulic pump (21) is respectively 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 jointly supply oil to the lifting cylinder (13).

2. The hydraulic system in the hydrogen-electric hybrid container empty box stacker according to claim 1 is characterized in that: The lifting valve assembly (12) comprises 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 descend, 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) is returned through the solenoid valve (122) to unload the oil.

3. The hydraulic system in the hydrogen-electric hybrid container empty box stacker according to claim 2 is characterized in that: The lifting valve assembly (12) further comprises a merging check valve (123), the oil input port of the merging check valve (123) being connected to the electro-hydraulic proportional valve (4), and the oil output port of the merging check valve (123) being 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).

4. The hydraulic system in the hydrogen-electric hybrid container empty box forklift according to claim 2 is characterized in that: The lift valve assembly (12) further comprises a lift main overflow valve (124), which is arranged at the end of the lift pump (11) and is used to unload oil to protect the lift pump (11) when the lift valve assembly (12) is overloaded.

5. The hydraulic system in the hydrogen-electric hybrid container empty box forklift according to claim 2 is characterized in that: The lifting valve assembly (12) further comprises a secondary relief valve (125), which is arranged at the end of the lifting oil cylinder (13) and is used to protect the lifting oil cylinder (13) when an impact load occurs to the lifting valve assembly (12).

6. The hydraulic system in the hydrogen-electric hybrid container empty box handler according to claim 2 is characterized in that: The lifting valve assembly (12) also includes an emergency lowering electromagnetic valve (126) for allowing the lifted heavy object to slowly fall down when the stacker fails.

7. The hydraulic system in the hydrogen-electric hybrid container empty box forklift according to claim 1 is characterized in that: The invention also 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 filling pressure, the stacker cannot travel.

8. The hydraulic system in the hydrogen-electric hybrid container empty box handler according to claim 7 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).

9. The hydraulic system in the hydrogen-electric hybrid container empty box handler according to claim 1 is characterized in that: The lifting system (1) also includes a lifting filter (14), which 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.

10. The hydraulic system in the hydrogen-electric hybrid container empty box handler according to claim 1 is characterized in that: The lifting system (1) further comprises 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 limit value; At the same time, the flow limiting valve (15) can also prevent the oil pipe from bursting when the lifting cylinder (13) performs a descending action, thereby preventing the lifted heavy object from stalling.

Images