Integrated valve block of a hydraulic system, hydraulic system and forklift

Abstract

The present invention discloses an integrated valve block for a hydraulic system, a hydraulic system and a forklift truck, comprising: a steering priority valve, a sequence control valve, a filling valve and a solenoid valve; a hydraulic oil inlet is respectively communicated with the inlet of the steering priority valve and the inlet of the sequence control valve; a steering gear feedback port is respectively connected with the control port of the steering priority valve, the control port of the sequence control valve and the control port of the filling valve; the outlet of the steering priority valve is communicated with the oil supply port of the steering gear; the outlet of the sequence control valve is respectively communicated with the inlet of the filling valve and the oil supply port of the multi-way valve; an accumulator charging port is respectively communicated with the outlet of the filling valve and the inlet of the solenoid valve; the outlet of the solenoid valve is communicated with the oil supply port of the parking brake. By integrating the priority valve, the filling valve, the solenoid valve and the pressure reducing valve onto one valve block, the present invention greatly reduces the installation space required, reduces the pipeline connection and leakage points, and is convenient for detection and maintenance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, in particular to an integrated valve block for a hydraulic system, a hydraulic system and a forklift. Background Art

[0002] The existing steering priority valve, fluid charging valve, solenoid valve and pressure reducing valve of a forklift are independent of each other and are connected through pipelines. The installation is complex, there are many pipelines, and there are many risk points of leakage.

[0003] See Figure 1 As shown, the existing hydraulic system is provided with hydraulic oil by a hydraulic pump 5'. The steering priority valve 1' gives priority to supplying oil to the steering gear to realize the steering function. The remaining hydraulic oil passes through the fluid charging valve 2'. When the hydraulic oil stored in the accumulator 6' is lower than the set value, the fluid charging valve pressurizes the accumulator 6', and cuts off when it is charged to the set maximum pressure. Then the hydraulic oil is supplied to the multi-way valve to realize other hydraulic actions (such as realizing lifting and tilting functions). The hydraulic oil of the accumulator 6' provides the pressure required for parking brake or relieves the pressure required for parking through the solenoid valve 3' and the pressure reducing valve 4'. The accumulator 6' also provides hydraulic oil for the service brake and controls the service brake through the brake valve 7'. These existing valves all use independent valves and are installed independently, and these valves are connected through joints and pipelines to realize the functions required by the forklift. Summary of the Invention

[0004] The main object of the present invention is to overcome the above-mentioned defects in the prior art, and propose an integrated valve block for a hydraulic system, a hydraulic system and a forklift. By integrating the steering priority valve, the fluid charging valve, the solenoid valve and the pressure reducing valve onto one valve block, the installation space required is greatly reduced, the pipeline connection and leakage points are reduced, and at the same time, it is convenient for detection and maintenance.

[0005] The present invention adopts the following technical solutions:

[0006] On the one hand, an integrated valve block for a hydraulic system includes: a steering priority valve, a sequence control valve, a fluid charging valve, a solenoid valve, a hydraulic oil inlet P, a steering gear oil supply port ST, a steering gear feedback port LS, an accumulator pressurizing port R, a parking brake oil supply port CP and a multi-way valve oil supply port EF; the hydraulic oil inlet P is respectively communicated with the inlet of the steering priority valve and the inlet of the sequence control valve; the steering gear feedback port LS is respectively connected with the control port of the steering priority valve, the control port of the sequence control valve and the control port of the fluid charging valve to control the opening degree; the output port of the steering priority valve is communicated with the steering gear oil supply port ST; the outlet of the sequence control valve is respectively communicated with the inlet of the fluid charging valve and the multi-way valve oil supply port EF; the accumulator pressurizing port R is respectively communicated with the outlet of the fluid charging valve and the inlet of the pressure reducing valve; the outlet of the pressure reducing valve is connected with the inlet of the solenoid valve; the outlet of the solenoid valve is connected with the parking brake oil supply port CP.

[0007] Preferably, the integrated valve block of the hydraulic system further includes: a pressure reducing valve; the accumulator charging port R is connected to the inlet of the pressure reducing valve; the outlet of the pressure reducing valve is connected to the inlet of the solenoid valve.

[0008] Preferably, the integrated valve block of the hydraulic system further includes: a fuel tank interface; the oil return port of the filling valve is connected to the fuel tank interface to return the signal control oil to the fuel tank when the oil pressure at the outlet of the filling valve reaches the first set value.

[0009] Preferably, the integrated valve block of the hydraulic system further includes: a fuel tank interface; the oil return port of the pressure reducing valve is connected to the fuel tank interface to return the hydraulic oil to the fuel tank when the oil pressure at the outlet of the pressure reducing valve reaches the second set value.

[0010] Preferably, the integrated valve block of the hydraulic system further includes: a fuel tank interface; the oil return port of the solenoid valve is connected to the fuel tank interface to return the hydraulic oil of the parking brake to the fuel tank when the solenoid valve loses power.

[0011] Preferably, the integrated valve block of the hydraulic system further includes: a steering pressure sensor interface, a filling pressure sensor interface F, and a parking brake pressure sensor interface CP1; the steering pressure sensor interface is used to connect a steering pressure sensor and a steering priority valve; the filling pressure sensor interface F is used to connect a filling pressure sensor and a filling valve; the parking brake pressure sensor interface CP1 is used to connect a parking brake pressure sensor and a solenoid valve; the steering pressure sensor interface and the steering gear feedback port LS share one interface.

[0012] Preferably, the integrated valve block of the hydraulic system further includes: a shuttle valve provided between the steering gear feedback port LS and the control port of the sequence control valve.

[0013] On the other hand, a hydraulic system includes: a hydraulic pump, an accumulator, and the integrated valve block respectively connected to the hydraulic pump and the accumulator.

[0014] Preferably, the hydraulic system further includes a brake valve; the inlet of the brake valve is connected to the accumulator; the outlet of the brake valve is connected to the service brake.

[0015] On yet another aspect, a forklift includes: a steering gear, a multi-way valve, a parking brake, a service brake, and the hydraulic system respectively connected to the steering gear, the multi-way valve, the parking brake, and the service brake.

[0016] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention integrates a steering priority valve, a fluid filling valve, a solenoid valve, and a pressure reducing valve onto a valve block. At the same time, hydraulic oil inlet P, steering gear oil supply port ST, steering gear feedback port LS, accumulator charging port R, parking brake oil supply port CP, and multi-way valve oil supply port EF are opened on the valve block to realize the connection or connection between each valve and between each valve and external devices (valves, controllers, etc.). On the one hand, it meets the forklift's control and management requirements for hydraulic oil. On the other hand, the compact design simplifies the layout, eliminates a large number of pipelines and joints, saves costs while reducing the leakage points, and is convenient for detection, maintenance, and repair;

[0018] (2) The integrated valve block of the present invention can simultaneously connect the steering priority valve, the fluid filling valve, the solenoid valve, and the multi-way valve, that is, it can realize multiple operations such as steering, fluid filling, and other hydraulic actions (such as lifting and tilting operations) simultaneously. In addition, the fluid filling in this embodiment is realized through a fluid filling valve controlled by a spool sequence, with small pressure loss and energy consumption, and can quickly charge the accumulator with small deviation;

[0019] (3) The integrated valve block of the present invention further includes a fuel tank interface, and the oil return ports of the pressure reducing valve, the oil return port of the pressure reducing valve, and the oil return port of the solenoid valve are respectively connected to the fuel tank interface, so as to realize the unloading and recovery of the oil;

[0020] (4) The integrated valve block of the present invention further includes a steering pressure sensor interface, a fluid filling pressure sensor interface F, and a parking brake pressure sensor interface CP1 respectively connected to pressure sensors, so as to realize the monitoring of the oil pressure in the steering priority valve, the fluid filling valve, and the solenoid valve, and facilitate alarm and control in case of faults or abnormal situations.

[0021] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present invention more obvious and understandable, the following specific embodiments of the present invention are listed.

[0022] Those skilled in the art will understand the above and other purposes, advantages, and features of the present invention more clearly according to the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. Brief Description of the Drawings

[0023] Figure 1 is the hydraulic schematic diagram of the forklift independent valve in the prior art;

[0024] Figure 2 is the hydraulic schematic diagram of the integrated valve block in the embodiment of the present invention;

[0025] Figure 3 is the three-dimensional schematic of the integrated valve block in the embodiment of the present invention Figure 1 ;

[0026] Figure 4 Schematic perspective view of the integrated valve block according to an embodiment of the present invention Figure 2 ;

[0027] Figure 5 Structural block diagram of the hydraulic system according to an embodiment of the present invention;

[0028] Figure 6 Structural block diagram of the forklift according to an embodiment of the present invention;

[0029] The reference numerals are as follows:

[0030] 1. Integrated valve block; 10. Steering priority valve; 11. Sequence control valve; 12. Fill valve; 13. Pressure reducing valve; 14. Solenoid valve; 15. Shuttle valve; 2. Hydraulic system; 20. Hydraulic pump; 21. Accumulator; 22. Brake valve; 23. Steering pressure sensor; 24. Fill pressure sensor; 25. Parking brake pressure sensor; 26. Check valve; 27. Filter; 3. Steering gear; 4. Multi-way valve; 5. Parking brake; 6. Service brake; 7. Fuel tank. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0033] In the present application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or diagonally above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may mean that the first feature is directly below or diagonally below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0037] As an industrial handling vehicle, a forklift is indispensable for the development of modern industry. Industrial handling vehicles are widely used in ports, stations, airports, freight yards, factory workshops, warehouses, distribution centers and other places. Moreover, forklifts can enter cabins, carriages and containers for the loading, unloading and handling operations of pallet goods, and are essential equipment in pallet transportation and container transportation.

[0038] A forklift generally has multiple functions such as steering, braking and lifting. Among them, the steering and braking of the forklift require continuous oil supply, and the lifting of the forklift requires a large flow of oil supply (non - continuous oil supply). In existing forklifts, separate liquid pumps and / or separate inlet valves for oil supply are respectively provided for modules such as steering, braking and lifting of the forklift. Thus, the volume of the forklift is increased, as well as the manufacturing and maintenance costs of the forklift.

[0039] See Figures 2 to 4As shown in the figure, an integrated valve block 1 of a hydraulic system includes: a steering priority valve 10, a sequence control valve 11, a filling valve 12, a pressure reducing valve 13, a solenoid valve 14, a hydraulic oil inlet P, a steering gear oil supply port ST, a steering gear feedback port LS, an accumulator charging port R, a parking brake oil supply port CP, and a multi-way valve oil supply port EF; the hydraulic oil inlet P is respectively communicated with the inlet of the steering priority valve 10 and the inlet of the sequence control valve 11; the steering gear feedback port LS is respectively connected to the control port of the steering priority valve 10, the control port of the sequence control valve 11, and the control port of the filling valve 12 to control the opening degree; the output port of the steering priority valve 10 is communicated with the steering gear oil supply port ST; the outlet of the sequence control valve 11 is respectively communicated with the inlet of the filling valve 12 and the multi-way valve oil supply port EF; the accumulator charging port R is respectively communicated with the outlet of the filling valve 12 and the inlet of the pressure reducing valve 13; the outlet of the pressure reducing valve 13 is connected to the inlet of the solenoid valve 14; the outlet of the solenoid valve 14 is connected to the parking brake oil supply port CP.

[0040] It should be noted that the above term "communicated" is used to express connection through a through hole, and the through hole allows hydraulic oil to pass through to reflect the integrated valve block of the present invention. The above term "connected" is used to distinguish from "communicated" and can be understood as an electrical connection for transmitting signals. The subsequent term "connected" can include electrical connection, pipeline connection, through hole connection, mechanical connection, direct connection, indirect connection, etc.

[0041] Specifically, the hydraulic oil inlet P is used to be connected to a hydraulic pump 20 to provide hydraulic oil for the hydraulic system of a forklift. The steering gear oil supply port ST is used to be connected to the inlet of the steering gear 3 to provide sufficient oil for the steering gear 3. The steering gear feedback port LS is connected to the control end of the steering gear 3 and is used to feedback the steering state of the steering gear 3. The accumulator charging port R is used to be connected to an accumulator 21 to charge the accumulator 21. The parking brake oil supply port CP is used to be connected to a service brake 6 to provide oil for the service brake 6. The multi-way valve oil supply port EF is used to be connected to a controller that provides other functions (such as lifting, tilting, etc.) to provide oil for other controllers.

[0042] The pressure reducing valve 13 can reduce the high pressure of the accumulator 21 to the pressure range required by the parking brake 5, and the set pressure of the pressure reducing valve 13 is adjustable.

[0043] See Figure 3 and Figure 4As shown, in this embodiment, the integrated valve block 1 can be in the shape of a regular cuboid. Various holes are opened on the integrated valve block 1, presenting the above-mentioned various interfaces externally. At the same time, various cartridge valves (steering priority valve 10, sequence control valve 11, filling valve 12, pressure reducing valve 13, solenoid valve 14) are inserted into some of the holes. Preferably, the material of the integrated valve block 1 can be selected as QT500. QT500 ductile iron is a ferritic ductile iron with appropriate strength and toughness, which is convenient for cutting.

[0044] In this embodiment, the hydraulic oil coming from the hydraulic pump 20 enters the integrated valve block 1, first supplies oil to the steering gear 3 through the steering priority valve 10 for steering, then pressurizes the accumulator 21 through the filling valve 12, and finally the hydraulic oil enters the multi-way valve 4 to perform other hydraulic actions. The hydraulic oil of the accumulator 21 unlocks the parking brake through the pressure reduction of the pressure reducing valve 13 and the energization and connection of the solenoid valve 14. The hydraulic oil stored in the accumulator 21 is also used for service braking.

[0045] It should be noted that Figure 2 the control signal of the solenoid valve 14 is not shown in []. In actual application, when the solenoid valve 14 receives the parking brake unlocking signal, the solenoid valve 14 is energized and connected, and the parking brake is unlocked; when the solenoid valve 14 receives the parking brake signal, the solenoid valve 14 is de-energized and disconnected, and the parking brake is performed.

[0046] As above, the integrated valve block 1 of this embodiment can simultaneously connect the steering priority valve 10, the filling valve 12, the solenoid valve 14 and the multi-way valve 4, that is, it can realize the simultaneous execution of multiple operations among steering, filling and other hydraulic actions (such as lifting and tilting operations); in addition, the filling in this embodiment is realized through the filling valve 12 controlled by the spool sequence, with small pressure loss and energy consumption, and can quickly realize the pressurization of the accumulator with small deviation.

[0047] In this embodiment, the integrated valve block 1 of the hydraulic system further includes: a tank interface T. The filling valve 12 includes an oil return port, and the oil return port of the filling valve 12 is connected to the tank interface T to return the signal control oil to the tank 7 when the outlet oil pressure of the filling valve 12 reaches the first set value.

[0048] In this embodiment, the pressure reducing valve 13 includes an oil return port. The oil return port of the pressure reducing valve 13 is connected to the tank interface T to return the hydraulic oil to the tank 7 when the outlet oil pressure of the pressure reducing valve 13 reaches the second set value.

[0049] In this embodiment, the solenoid valve 14 includes an oil return port. The oil return port of the solenoid valve 14 is connected to the tank interface T to return the hydraulic oil of the parking brake 5 to the tank 7 when the solenoid valve 14 is de-energized.

[0050] It should be noted that the fluid filling valve 12, the pressure reducing valve 13, and the solenoid valve 14 can all open the oil return port, or one or two of them can start the oil return port, which is specifically set according to the actual situation and is not limited in this embodiment. The first set value and the second set value can be set according to the actual situation and are not limited in this embodiment.

[0051] In this embodiment, the oil return ports of the fluid filling valve 12, the pressure reducing valve 13, and the solenoid valve 14 are respectively connected to the tank interface T, so as to realize the unloading and recovery of the oil fluid, which not only ensures safety but also saves resources.

[0052] In this embodiment, the integrated valve block 1 of the hydraulic system further includes: a steering pressure sensor interface, a fluid filling pressure sensor interface F, and a parking brake pressure sensor interface CP1; the steering pressure sensor interface is used to connect the steering pressure sensor 23 and the steering priority valve 10; the fluid filling pressure sensor interface F is used to connect the fluid filling pressure sensor 24 and the fluid filling valve 12; the parking brake pressure sensor interface CP1 is used to connect the parking brake pressure sensor 25 and the solenoid valve 14.

[0053] See Figure 2 As shown, in this embodiment, the steering pressure sensor interface and the steering gear feedback port LS share one interface.

[0054] The settings of the steering pressure sensor interface, the fluid filling pressure sensor interface F, and the parking brake pressure sensor interface CP1 can realize the monitoring of the oil pressure in the steering priority valve 10, the fluid filling valve 12, and the solenoid valve 14, which is convenient for timely alarm and control in case of failure or abnormal situation.

[0055] In this embodiment, the integrated valve block 1 of the hydraulic system further includes: a shuttle valve 15 arranged between the steering gear feedback port LS and the control port of the sequence control valve 11, so as to realize sequence control through the sequence control valve 11 and meet the supply demand of the hydraulic oil.

[0056] See Figure 5 As shown, a hydraulic system of the present invention includes: a hydraulic pump 20, an accumulator 21, and the integrated valve block 1 respectively connected to the hydraulic pump 20 and the accumulator 21.

[0057] In the hydraulic system of this embodiment, it further includes a brake valve 22; the inlet of the brake valve 22 is connected to the accumulator 21; the outlet of the brake valve 22 is connected to the service brake 6.

[0058] In this embodiment, the brake valve 22 includes an oil return port. The oil return port of the brake valve 22 is connected to the tank interface T to return the hydraulic oil of the service brake to the fuel tank 7 when the brake valve 22 stops being depressed.

[0059] In the present embodiment, the hydraulic system further includes a check valve 26 and a filter 27 disposed between the hydraulic pump 20 and the hydraulic oil inlet P. The check valve 26 can prevent the hydraulic oil from flowing back into the hydraulic pump 20, and the filter 27 filters the hydraulic oil output by the hydraulic pump 20 to prevent impurities from entering the integrated valve block 1 and causing blockage of the channels or interfaces.

[0060] The steering priority valve 10, sequence control valve 11, filling valve 12, pressure reducing valve 13, and solenoid valve 14 of the present invention are all mounted on the vehicle frame and thus can be integrated onto an integrated valve block 1. Since the brake valve 22 is foot-operated and must be installed in the cab, and the cab needs to be flipped, if the brake valve 22 is also integrated, it will result in a very complex pipeline layout. Therefore, the brake valve 22 is not integrated in the present invention.

[0061] The specific implementation and functions of the integrated valve block 1 in a hydraulic system are as described above and will not be repeated here.

[0062] See Figure 6 As shown, a forklift of the present invention includes: a steering gear 3, a multi-way valve 4, a parking brake 5, a service brake 6, and a hydraulic system 2 respectively connected to the steering gear 3, multi-way valve 4, parking brake 5, and service brake 6.

[0063] In the present embodiment, the forklift includes a heavy forklift.

[0064] The specific implementation and functions of the hydraulic system 2 in a forklift are as described above and will not be repeated here.

[0065] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0066] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An integrated valve block for a hydraulic system, characterized in that Comprising: A steering priority valve (10), a sequence control valve (11), a filling valve (12), a solenoid valve (14), a hydraulic oil inlet P, a steering gear oil supply port ST, a steering gear feedback port LS, an accumulator charging port R, a parking brake oil supply port CP, a multi-way valve oil supply port EF, and a shuttle valve (15); the hydraulic oil inlet P is respectively communicated with the inlet of the steering priority valve (10) and the inlet of the sequence control valve (11); the output port of the steering priority valve (10) is communicated with the steering gear oil supply port ST; the filling valve (12) is a three-position four-way valve, and the filling valve (12) includes an inlet, an outlet, a signal feedback port, an oil return port, and an upper end control port; the sequence control valve (11) has two outlets, one outlet of the sequence control valve (11) is communicated with the inlet of the filling valve (12), and the other outlet of the sequence control valve (11) is communicated with the multi-way valve oil supply port EF; the accumulator charging port R is respectively communicated with the outlet of the filling valve (12) and the inlet of the solenoid valve (14); the outlet of the solenoid valve (14) is communicated with the parking brake oil supply port CP; The hydraulic oil inlet P is connected to the upper control port of the sequence control valve (11) through a throttle valve; the first inlet of the shuttle valve (15) is connected to the steering gear feedback port LS, the second inlet of the shuttle valve (15) is connected to the signal feedback port of the filling valve (12) through another throttle valve, and the outlet of the shuttle valve (15) is connected to the lower control port of the sequence control valve (11); the sequence control valve (11) drives the spool to move to different working positions based on the pressure signal difference between the upper control port, the lower control port and the pressure signal of the spring, so as to supply oil or not supply oil to the filling valve (12) and / or the oil supply port EF of the multi-way valve; the accumulator charging port R is connected to the upper control port of the filling valve (12), and the filling valve (12) drives the spool to move to different working positions based on the pressure signal difference between the upper control port and the pressure signal of the lower spring, so as to charge or not charge the accumulator charging port R. The integrated valve block further includes a fuel tank interface T, and the oil return port of the filling valve (12) is connected to the fuel tank interface T to return the signal control oil to the fuel tank when the outlet oil pressure of the filling valve (12) reaches the first set value. When the filling valve (12) is in the first lower working position, the inlet of the filling valve (12) is connected to the signal feedback port, the inlet and the outlet of the filling valve (12) are connected unidirectionally through a check valve, the oil return port of the filling valve (12) is connected to the fuel tank (7), and the oil return port of the filling valve (12) is not connected to the inlet, the signal feedback port and the outlet of the filling valve (12); when the filling valve (12) is in the middle working position, the inlet and the outlet of the filling valve (12) are connected unidirectionally through a check valve, the oil return port and the signal feedback port of the filling valve (12) are connected and connected to the fuel tank (7), and the inlet, the outlet and the signal feedback port of the filling valve (12) are not connected; when the filling valve (12) is in the second upper working position, the inlet of the filling valve (12) is not connected to the signal feedback port, the outlet and the oil return port, the oil return port and the signal feedback port of the filling valve (12) are connected, and the oil return port and the outlet of the filling valve (12) are connected unidirectionally through a check valve.

2. The integrated valve block of the hydraulic system according to claim 1, characterized in that It also includes: A pressure reducing valve (13); the accumulator charging port R is connected to the inlet of the pressure reducing valve (13); the outlet of the pressure reducing valve (13) is connected to the inlet of the solenoid valve (14).

3. The integrated valve block of the hydraulic system according to claim 2, characterized in that, It also includes: The oil return port of the pressure reducing valve (13) is connected to the fuel tank interface T to return the hydraulic oil to the fuel tank (7) when the outlet oil pressure of the pressure reducing valve (13) reaches the second set value.

4. The integrated valve block of the hydraulic system according to claim 1, characterized in that, It also includes: The oil return port of the solenoid valve (14) is connected to the fuel tank interface T to return the hydraulic oil of the parking brake to the fuel tank (7) when the solenoid valve (14) loses power.

5. A hydraulic system, characterized in that, It includes: A hydraulic pump (20), an accumulator (21), and the integrated valve block (1) according to any one of claims 1 to 4, wherein the hydraulic pump (20) is connected to the hydraulic oil inlet P of the integrated valve block (1), and the accumulator (21) is connected to the accumulator charging port R of the integrated valve block (1).

6. The hydraulic system according to claim 5, characterized in that, It further includes a brake valve (22); the inlet of the brake valve (22) is in communication with the accumulator (21); the outlet of the brake valve (22) is in communication with the service brake.

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