A brake integrated valve block and a dual-circuit wet brake system using the valve block

Abstract

The present invention discloses a brake integrated valve block in the field of brake systems and a dual-circuit wet brake system using the valve block. The system comprises a first brake circuit and a second brake circuit. The first brake circuit and the second brake circuit comprise a three-position four-way solenoid valve. The three-position four-way solenoid valve is arranged between the dual-circuit hydraulic brake valve and the first check valve and the second check valve. One group of oil ports are respectively connected to the first oil outlet of the dual-circuit hydraulic brake valve and the first oil inlet of the first check valve, and the other group of oil ports are respectively connected to the second oil outlet of the dual-circuit hydraulic brake valve and the first oil inlet of the second check valve. The system also comprises an emergency brake circuit led by an emergency accumulator, a two-position two-way proportional valve, a first check valve, a second check valve, a three-position four-way solenoid valve, and a dual-circuit hydraulic brake valve. The present invention can avoid sudden braking and prevent goods from being thrown out. It provides two brake circuits and one emergency brake circuit, and can provide sufficient safety support.

Description

Technical Field

[0001] The invention relates to the field of brake systems, in particular to a brake integrated valve block and a dual-circuit wet brake system using the valve block. Background Art

[0002] At present, heavy vehicles, such as heavy forklifts, empty container stackers and full container cranes, use a single brake circuit wet brake system. Figure 1 As shown, the gear pump 04 draws hydraulic oil from the hydraulic oil tank 01 through the oil suction filter 03 and provides it to the filling valve 05. The hydraulic oil enters the accumulator 07 through the filling valve 05 to fill the liquid, and enters the drive axle 012 to provide the hydraulic oil required for cooling the brakes on both sides. The drive axle 012 is connected to the blockage alarm switch 013, the brake light switch 011, and the hydraulic oil tank 01, and the left pedal 010 and the right pedal 08 are connected through the shuttle valve 09. The left pedal 010 and the right pedal 08 are also connected to the accumulator 07 and the low pressure alarm switch 06. The above scheme has the following disadvantages:

[0003] 1. When the whole machine is fully loaded, the speed of the whole vehicle cannot be too high, otherwise the safety during operation cannot be guaranteed; and when fully loaded, the brake cannot be automatically identified and controlled, but still depends on human subjective judgment. There is a situation where the driver still drives at full speed under fully loaded conditions and cannot brake in time;

[0004] 2. Once the pipeline of a single-circuit system explodes, the emergency brake disc will lock instantly, and the cargo may be thrown out, which is even more dangerous. Summary of the invention

[0005] The object of the present invention is to provide a brake integrated valve block and a dual-circuit wet brake system using the valve block, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A brake integrated valve block comprises a valve housing, wherein the valve housing is provided with a dual-circuit filling valve composed of a main valve, a two-position three-way control valve, a first two-position two-way control valve and a second two-position two-way control valve connected to form a relief valve and a back-pressure check valve, wherein the H1 oil port of the back-pressure check valve is connected to the PA oil port of the valve housing and the H3 oil port of the relief valve, the H2 oil port of the back-pressure check valve is connected to the P1 oil port of the valve housing, and the H4 oil port of the relief valve is connected to the T2 oil port of the valve housing.

[0008] As an improved solution of the present invention, the D1 oil port of the first two-position two-way control valve is connected to the D2 oil port of the second two-position two-way control valve, the D3 oil port of the first two-position two-way control valve is connected to the A1 oil port of the valve housing, and the D4 oil port of the second two-position two-way control valve is connected to the A2 oil port of the valve housing; the E oil port and the G oil port of the two-position three-way control valve are connected and then connected together to the D2 oil port of the second two-position two-way control valve, and its F oil port is connected to the B3 oil port of the main valve on one side and to the T1 oil port of the valve housing on the other side; the B1 oil port of the main valve is respectively connected to the N oil port and the P1 oil port of the valve housing, and its B2 oil port is connected to the D1 oil port of the first two-position two-way control valve and the D2 oil port of the second two-position two-way control valve, and its B4 oil port is connected to the P1 oil port of the valve housing.

[0009] As an improved solution of the present invention, the model of the dual-circuit filling valve is ACV-L25F-00A.

[0010] A dual-circuit wet brake system using the above-mentioned brake integrated valve block comprises a first brake circuit mainly led out by the A1 oil port of the brake integrated valve block and connected in sequence with the dual-circuit hydraulic brake valve, the first non-return valve and the first wet brake, the A1 oil port of the brake integrated valve block is also connected to a first accumulator; and a second brake circuit mainly led out by the A2 oil port of the brake integrated valve block and connected in sequence with the dual-circuit hydraulic brake valve, the second non-return valve and the second wet brake, the A2 oil port of the brake integrated valve block is also connected to a second accumulator; the P1 oil port, the T1 oil port and the T2 oil port of the brake integrated valve block are all connected to a hydraulic oil tank; and further comprises a three-position four-way solenoid valve, the three-position four-way solenoid valve is arranged between the dual-circuit hydraulic brake valve and the first non-return valve and the second non-return valve, one group of its oil ports are respectively connected to the first oil outlet of the dual-circuit hydraulic brake valve and the first oil inlet of the first non-return valve, and the other group of its oil ports are respectively connected to the second oil outlet of the dual-circuit hydraulic brake valve and the first oil inlet of the second non-return valve.

[0011] As an improved solution of the present invention, the PA oil port of the brake integrated valve block is connected to the emergency accumulator and the first oil port of the two-position two-way proportional valve; the first one-way valve is connected to the second oil inlet of the second one-way valve, and are jointly connected to the second oil port of the two-position two-way proportional valve, and the T3 and T4 oil ports of the dual-circuit hydraulic brake valve are both connected to the hydraulic oil tank.

[0012] As an improved solution of the present invention, the PA oil port of the brake integrated valve block is also connected to an emergency accumulator; in the first brake circuit, the A1 oil port of the brake integrated valve block is also connected to a first low-pressure alarm switch, and a first pressure sensor is connected between the dual-circuit hydraulic brake valve and the three-position four-way solenoid valve; in the second brake circuit, the A2 oil port of the brake integrated valve block is also connected to a second low-pressure alarm switch, and a second pressure sensor is connected between the dual-circuit hydraulic brake valve and the three-position four-way solenoid valve.

[0013] As an improved solution of the present invention, it also includes an electrical controller, which is electrically connected to the first low-pressure alarm switch, the second low-pressure alarm switch, the first pressure sensor, the second pressure sensor, the three-position four-way solenoid valve and the two-position two-way proportional valve.

[0014] As an improved solution of the present invention, it also includes a cooling circuit led out from the N oil port of the brake integrated valve block, the two cooling oil ports of the first wet brake are correspondingly connected to the two cooling oil ports of the second wet brake, the N oil port of the brake integrated valve block is connected to one of the cooling oil ports of the first wet brake, and one of the cooling oil ports of the second wet brake is connected to the hydraulic oil tank through a built-in return oil filter.

[0015] As an improved solution of the present invention, the model of the dual-circuit hydraulic brake valve is HBV3-L10F-00.

[0016] The present invention has the following beneficial effects:

[0017] 1. When the vehicle is fully loaded and the driver controls the brakes, the brake oil pressure can be actively controlled to avoid sudden braking while ensuring safe operation, effectively preventing the cargo from being thrown out;

[0018] 2. With the first brake circuit and the second brake circuit, even if one brake circuit is damaged, the whole vehicle can be braked and it is not easy to drift.

[0019] 3. When both circuits are damaged or fail, the emergency accumulator can switch immediately to ensure reliable, autonomous and smooth braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a brake system in the prior art;

[0021] Figure 2 It is a schematic diagram of the present invention.

[0022] In the figure: 1-hydraulic oil tank; 2-oil suction filter; 3-gear pump; 4-motor; 5-brake integrated valve block; 51-main valve; 52-two-position three-way control valve; 53-second two-position two-way control valve; 54-first two-position two-way control valve; 55-overflow valve; 56-back pressure check valve; 6-emergency accumulator; 7-first accumulator; 8-second accumulator; 9-second low-pressure alarm switch; 10-first low-pressure alarm switch; 11-dual-circuit hydraulic brake valve; 12-second pressure sensor; 13-first pressure sensor; 14-three-position four-way solenoid valve; 15-first check valve; 16-second check valve; 17-second wet brake; 18-built-in return oil filter; 19-electric controller; 20-tank breather cap; 21-two-position two-way proportional valve; 22-first wet brake. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 2 A brake integrated valve block includes a valve housing, in which a double-circuit filling valve is arranged, which is composed of a main valve 51, a two-position three-way control valve 52, a first two-position two-way control valve 54 and a second two-position two-way control valve 53. The model of the double-circuit filling valve can be ACV-L25F-00A.

[0025] The brake integrated valve block also includes an overflow valve 55 and a back pressure check valve 56. The H1 oil port of the back pressure check valve 56 is connected to the PA oil port of the valve housing and the H3 oil port of the overflow valve 55. The H2 oil port of the back pressure check valve 56 is connected to the P1 oil port of the valve housing. The H4 oil port of the overflow valve 55 is connected to the T2 oil port of the valve housing.

[0026] Specifically, the D1 oil port of the first two-position two-way control valve 54 is connected to the D2 oil port of the second two-position two-way control valve 53 through a three-way joint, the D3 oil port of the first two-position two-way control valve 54 is connected to the A1 oil port of the valve housing, and the D4 oil port of the second two-position two-way control valve 53 is connected to the A2 oil port of the valve housing.

[0027] The E oil port and the G oil port of the two-position three-way control valve 52 are connected to the D2 oil port of the second two-position two-way control valve 53, and its F oil port is connected to the B3 oil port of the main valve 51 on one side and to the T1 oil port of the valve housing on the other side.

[0028] The B1 oil port of the main valve 51 is connected to the N oil port and the P1 oil port of the valve housing respectively, and the B2 oil port is connected to the D1 oil port of the first two-position two-way control valve 54 and the D2 oil port of the second two-position two-way control valve 53 at the three-way joint, specifically: Figure 2 At point C shown in the figure, the B4 oil port is connected to the P1 oil port of the valve housing.

[0029] A dual-circuit wet brake system uses the above-mentioned brake integrated valve block 5. The hydraulic oil tank 1 of the brake system is installed on one side of the vehicle frame, and the hydraulic oil tank 1 is equipped with an oil tank breather cap 20. The oil suction port of the gear pump 3 is directly connected to the oil suction filter 2 built into the hydraulic oil tank 1. The motor 4 is connected to the gear pump 3 to drive the gear pump 3 to rotate, and the outlet of the gear pump 3 is connected to the P1 oil port of the valve housing.

[0030] This braking system includes a first braking circuit and a second braking circuit. The first braking circuit is: the A1 oil port of the brake integrated valve block 5 is led to the K6 port, the K6 port is connected to the first oil inlet (P3 oil port) of the dual-circuit hydraulic brake valve 11 and the first accumulator 7, the first oil outlet (A3 oil port) of the dual-circuit brake valve 11 is connected to the J1 oil port on the three-position four-way solenoid valve 14, the J2 oil port of the three-position four-way solenoid valve 14 is connected to the first oil inlet (J5 oil port) of the first check valve 15, and the J5 oil port is connected to the K2 oil port of the first wet brake 22.

[0031] The second brake circuit is: the A2 oil port of the brake integrated valve block 5 is led out to the K5 port, the K5 port is connected to the second oil inlet (P4 oil port) of the dual-circuit hydraulic brake valve 11 and the second accumulator 8, the second oil outlet (A4 oil port) of the dual-circuit brake valve 11 is connected to the J2 oil port on the three-position four-way solenoid valve 14, the J4 oil port of the three-position four-way solenoid valve 14 is connected to the first oil inlet (J8 oil port) of the second one-way valve 15, and the J8 oil port is connected to the K3 oil port of the second wet brake 17.

[0032] Preferably, the model of the dual-circuit hydraulic brake valve can be selected as HBV3-L10F-00.

[0033] In the system, the P1 oil port, the T1 oil port, the T2 oil port of the brake integrated valve block 5 and the T3 oil port, the T4 oil port of the dual-circuit hydraulic brake valve 11 are all connected to the hydraulic oil tank 1 .

[0034] Further, the system also includes an emergency brake circuit, wherein the second oil inlet (J6 oil port) of the first check valve 15 is connected to the second oil inlet (J7 oil port) of the second check valve 16, and is commonly connected to the second oil port (P8 oil port) of the two-position two-way proportional valve 21, and the first oil port (P7 oil port) of the two-position two-way proportional valve 21 is connected to the PA oil port of the brake integrated valve block 5 and the emergency accumulator 6. The emergency brake circuit includes a circuit consisting of the emergency accumulator 6, the two-position two-way proportional valve 21, the first check valve 15, the second check valve 16, the three-dimensional four-way solenoid valve 14, the dual-circuit hydraulic brake valve 11, and the hydraulic oil tank 1 in sequence.

[0035] Furthermore, in the first brake circuit, the A1 oil port of the brake integrated valve block 5 is also connected to a first low-pressure alarm switch 10, and a first pressure sensor 13 is connected between the dual-circuit hydraulic brake valve 11 and the three-position four-way solenoid valve 14; in the second brake circuit, the A2 oil port of the brake integrated valve block 5 is also connected to a second low-pressure alarm switch 9, and a second pressure sensor 12 is connected between the dual-circuit hydraulic brake valve 11 and the three-position four-way solenoid valve 14.

[0036] Furthermore, the system also includes an electrical controller 19 , which is electrically connected to the first low-pressure alarm switch 10 , the second low-pressure alarm switch 9 , the first pressure sensor 13 , the second pressure sensor 12 , the three-position four-way solenoid valve 14 and the two-position two-way proportional valve 21 .

[0037] Furthermore, the system also includes a cooling circuit led out from the N oil port of the brake integrated valve block 5, specifically: the two cooling oil ports of the first wet brake 22 are correspondingly connected to the two cooling oil ports of the second wet brake 17, the N oil port of the brake integrated valve block 5 is connected to one of the cooling oil ports (K1 oil port) of the first wet brake 22, and one of the cooling oil ports (K4 oil port) of the second wet brake 17 is connected to the hydraulic oil tank 1 through the built-in return oil filter 18.

[0038] The implementation principle of this system is explained below.

[0039] 1. When the vehicle is in normal working condition, the implementation principle of this system is:

[0040] When the whole machine is working, the gear pump 3 draws hydraulic oil from the hydraulic oil tank 1 through the oil suction filter 2 and supplies it to the P1 oil port on the brake integrated valve block 5. The high-pressure oil passes through the B1 oil port and the B2 oil port of the main valve 51 inside the brake integrated valve block 5, and is supplied from the B2 oil port to the first two-position two-way control valve 54 and the second two-position two-way control valve 53. The high-pressure oil enters the first two-position two-way control valve 54 through the D1 oil port, and then fills the first accumulator 7 through the D3 oil port and the A1 oil port. Similarly, the high-pressure oil passes through the D2 oil port and the D4 oil port of the second two-position two-way control valve 53, and then fills the second accumulator 8 through the A2 oil port.

[0041] When the internal pressure of the first accumulator 7 and the second accumulator 8 reaches the set pressure, the internal pressure of the first accumulator 7 and the second accumulator 8 is fed back to the D3 oil port and the D4 oil port on the first two-position two-way control valve 54 and the second two-position two-way control valve 53 through the A1 oil port and the A2 oil port on the brake integrated valve block 5, directly controlling the valve core of the first two-position two-way control valve 54 and the second two-position two-way control valve 53 to move to the corresponding closed oil circuit. At this time, the first two-position two-way control valve 54 and the second two-position two-way control valve 53 almost cut off the oil circuit, and the main valve 51 stops supplying high-pressure oil to the first two-position two-way control valve 54 and the second two-position two-way control valve 53.

[0042] At this time, the two-position three-way control valve 52 starts to work, and the oil from the main valve 51 will enter the F oil port on the two-position three-way control valve 52 through the B3 oil port, and then flow back to the T1 oil port on the brake integrated valve block 5.

[0043] The excess oil is provided to the first wet brake 22 and the second wet brake 17 for internal cooling through the N oil port on the integrated brake integrated valve block 5. Finally, this oil passes through the K4 oil port and then returns to the hydraulic oil tank 1 through the built-in return oil filter 18.

[0044] The other route passes through the back pressure check valve 56 and directly fills the emergency accumulator 6. After the emergency accumulator 6 is full, any excess oil directly overflows from the overflow valve 55 back to the T2 oil port on the brake integrated valve block 5, and then flows back to the hydraulic oil tank 1.

[0045] At this time, the system has no demand for high-pressure oil, and the accumulator pressure will be maintained within a certain pressure range. The system is approximately in a balanced state, and the high-pressure oil reaches the P3 and P4 oil ports on the dual-circuit hydraulic brake valve 11, waiting for the instantaneous demand output when the brake is stepped on. If the driver steps on the brake pedal at this time, the upper and lower consistent valve cores on the dual-circuit hydraulic brake valve 11 start to work synchronously, and the A3 and A4 oil ports on the dual-circuit hydraulic brake valve 11 simultaneously output brake oil of a certain pressure and a certain flow required for braking, which passes through the J1 and J2 oil ports on the three-position four-way solenoid valve 14 directly to the J3 and J4 oil ports on the three-position four-way solenoid valve 14, and finally reaches the K2 and k3 oil ports on the first wet brake 22 and the second wet brake 17 to achieve braking of the entire machine.

[0046] This braking is controlled by the driver. At this time, the second low-pressure alarm switch 9, the first low-pressure alarm switch 10, the second pressure sensor 12, and the first pressure sensor 13 maintain a normal working state, will not alarm, and will not trigger the logic control sequence of the electrical controller 19.

[0047] 2. When the vehicle is fully loaded and brakes suddenly, the cargo is in front of the vehicle, and the combined center of gravity of the whole vehicle and the cargo moves forward. The sudden braking may cause the cargo to slide and other safety risks. In view of this, the implementation principle of this system is as follows:

[0048] When the driver steps on the dual-circuit hydraulic brake valve 11, oil of a certain pressure is output through the A3 and A4 oil ports on the dual-circuit hydraulic brake valve 11, and then the brake oil is provided to the first wet driver and the second wet brake 17 through the three-position four-way solenoid valve 14. The electrical controller 19 collects load data and vehicle speed data, and judges the activation timing of the intermediate throttling position of the valve core of the three-position four-way solenoid valve 14 based on the data. When activated, the high-pressure oil part of the three-position four-way solenoid valve 14 is cut to the intermediate throttling position of the three-position four-way solenoid valve 14, so that the full-load emergency braking is divided into two pressure levels, optimizing the braking time and braking force curve, making it more stable, so that the goods will not slide due to inertia, and at the same time, the braking distance after segmentation meets the standard requirements.

[0049] The electrical controller 19 compares the collected data with the preset program to calculate the time required for the best braking performance, so as to realize the system intelligent identification process that is knowable, controllable, adjustable and optimizable, and finally optimize the ratio of the opening of the three-position four-way solenoid valve 14. The model of the electrical controller 19 can be Parker MC43.

[0050] 3. When both the first brake circuit and the second brake circuit fail, the implementation principle of this system is:

[0051] When the whole vehicle braking cannot be achieved, that is, when the dual-circuit hydraulic brake valve 11 is damaged or the pipeline between the dual-circuit brake valve 11 and the brake integrated valve block 5 is damaged, the second pressure sensor 12 and the first pressure sensor 13 will sense the system pressure abnormality and transmit the pressure abnormality signal detected by the second pressure sensor 12 and the first pressure sensor 13 to the electrical controller 19. At this time, the electrical controller 19 provides a two-position two-way proportional valve 21 control signal to make the two-position two-way proportional valve 21 switch instantly so that the high-pressure oil stored in the emergency accumulator 6 passes through the two-position two-way proportional valve 21 to the P9 oil port, and then passes through the first one-way valve 15 and the second one-way valve 16 to enter the first wet brake 22 and the second wet brake 17 to implement emergency braking.

[0052] At this time, the three-position four-way solenoid valve 14 is powered and works in a state where all oil ports are not connected; when the whole machine stops, the brake oil pressure needs to be released. At this time, the three-position four-way solenoid valve 14 is powered and works in a state where the oil ports are connected. Since the A3 and A4 oil ports on the dual-circuit hydraulic brake valve 11 are respectively connected to the T3 and T4 oil ports on the dual-circuit hydraulic brake valve 11, the brake oil directly flows back to the hydraulic oil tank 1 to complete the brake release. The above process can realize system autonomous braking through the electrical controller 19, and the whole machine needs to be repaired in time when it stops.

[0053] During the implementation of the system, the oil tank breather cap 20 is used to complete the ventilation and pressure balance of the hydraulic oil tank 1. At the same time, in order to meet the needs, the connections between the J3 and J4 oil ports on the three-position four-way solenoid valve 14 and the first wet brake 22 and the second wet brake 17 must all be connected by steel pipes to prevent accidental pipeline explosion. At the same time, the steel pipe has poorer compressibility and can better meet the precise control of the brake oil pressure, providing technical advantages for single-channel, single-sided and smooth braking, ensuring that the single-channel, single-brake control machine will not deviate or skid at the current vehicle speed, thereby ensuring safe and reliable system operation.

[0054] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0055] In the description of the present invention, it should be noted that relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0056] In the description of the present invention, it is also necessary to explain that the orientations or positional relationships indicated by the terms "upper", "lower", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" 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 it can be an indirect connection through an intermediate medium, or it can be a connection between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent changes made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A dual-circuit wet brake system, comprising a first brake circuit mainly led out of an A1 oil port of a brake integrated valve block (5) and connected in sequence with a dual-circuit hydraulic brake valve (11), a first non-return valve (15) and a first wet brake (22), wherein the A1 oil port of the brake integrated valve block (5) is also connected to a first accumulator (7); and a second brake circuit mainly led out from the A2 oil port of the brake integrated valve block (5) and connected in sequence with a dual-circuit hydraulic brake valve (11), a second non-return valve (16) and a second wet brake (17); the A2 oil port of the brake integrated valve block (5) is also connected to a second accumulator (8); the P1 oil port, T1 oil port and T2 oil port of the brake integrated valve block (5) are all connected to a hydraulic oil tank (1); characterized in that, It also includes a three-position four-way solenoid valve (14), which is arranged between the dual-circuit hydraulic brake valve (11) and the first one-way valve (15) and the second one-way valve (16), wherein one group of oil ports are respectively connected to the first oil outlet of the dual-circuit hydraulic brake valve (11) and the first oil inlet of the first one-way valve (15), and the other group of oil ports are respectively connected to the second oil outlet of the dual-circuit hydraulic brake valve (11) and the first oil inlet of the second one-way valve (16); when the dual-circuit hydraulic brake valve (11) is stepped on, the oil sequentially passes through the dual-circuit hydraulic brake valve (11) and the three-position four-way solenoid valve (14) to provide brake oil to the first wet brake (22) and the second wet brake (17), respectively, and the electrical controller (19) collects load data and vehicle speed data, and accordingly stimulates the intermediate throttling position of the valve core of the three-position four-way solenoid valve (14), so that the high-pressure oil part is cut to the intermediate throttling position of the three-position four-way solenoid valve (14), so that the full-load emergency brake is divided into two pressure level stages; The brake integrated valve block (5) comprises a valve housing, in which a dual-circuit filling valve is arranged, which is composed of a main valve (51), a two-position three-way control valve (52), a first two-position two-way control valve (54) and a second two-position two-way control valve (53) connected to form a dual-circuit filling valve, characterized in that it also comprises an overflow valve (55) and a back pressure check valve (56), wherein the H1 oil port of the back pressure check valve (56) is connected to the PA oil port of the valve housing and the H3 oil port of the overflow valve (55), the H2 oil port of the back pressure check valve (56) is connected to the P1 oil port of the valve housing, and the H4 oil port of the overflow valve (55) is connected to the T2 oil port of the valve housing; The D1 oil port of the first two-position two-way control valve (54) is connected to the D2 oil port of the second two-position two-way control valve (53), the D3 oil port of the first two-position two-way control valve (54) is connected to the A1 oil port of the valve housing, and the D4 oil port of the second two-position two-way control valve (53) is connected to the A2 oil port of the valve housing; the E oil port of the two-position three-way control valve (52) is connected to the G oil port and then connected to the D2 oil port of the second two-position two-way control valve (53), the F oil port of the two-position three-way control valve (52) is connected to the B3 oil port of the main valve (51) on one side and to the T1 oil port of the valve housing on the other side; the B1 oil port of the main valve (51) is respectively connected to the N oil port and the P1 oil port of the valve housing, the B2 oil port of the two-position two-way control valve (54) is connected to the D1 oil port of the first two-position two-way control valve (54) and the D2 oil port of the second two-position two-way control valve (53), and the B4 oil port of the two-position three-way control valve (52) is connected to the P1 oil port of the valve housing.

2. The dual-circuit wet brake system according to claim 1, characterized in that: The PA oil port of the brake integrated valve block (5) is connected to the emergency accumulator (6) and the first oil port of the two-position two-way proportional valve (21); the first check valve (15) is connected to the second oil inlet of the second check valve (16), and is jointly connected to the second oil port of the two-position two-way proportional valve (21); the T3 and T4 oil ports of the dual-circuit hydraulic brake valve (11) are both connected to the hydraulic oil tank (1).

3. The dual-circuit wet brake system according to claim 1, characterized in that: In the first brake circuit, the A1 oil port of the brake integrated valve block (5) is also connected to a first low-pressure alarm switch (10), and a first pressure sensor (13) is connected between the dual-circuit hydraulic brake valve (11) and the three-position four-way solenoid valve (14); In the second brake circuit, the A2 oil port of the brake integrated valve block (5) is also connected to a second low-pressure alarm switch (9), and a second pressure sensor (12) is connected between the dual-circuit hydraulic brake valve (11) and the three-position four-way solenoid valve (14).

4. The dual-circuit wet brake system according to claim 3, characterized in that: It also includes an electrical controller (19), wherein the electrical controller (19) is electrically connected to the first low-pressure alarm switch (10), the second low-pressure alarm switch (9), the first pressure sensor (13), the second pressure sensor (12), the three-position four-way solenoid valve (14) and the two-position two-way proportional valve (21).

5. The dual-circuit wet brake system according to claim 4, characterized in that: It also includes a cooling circuit led out from the N oil port of the brake integrated valve block (5), wherein the two cooling oil ports of the first wet brake (22) are correspondingly connected to the two cooling oil ports of the second wet brake (17), the N oil port of the brake integrated valve block (5) is connected to one of the cooling oil ports of the first wet brake (22), and one of the cooling oil ports of the second wet brake (17) is connected to the hydraulic oil tank (1) via a built-in return oil filter (18).

6. The dual-circuit wet brake system according to any one of claims 1 to 5, characterized in that: The model of the dual-circuit hydraulic brake valve (11) is HBV3-L10F-00.

7. The dual-circuit wet brake system according to any one of claims 1 to 5, characterized in that: The model of the dual-circuit filling valve is ACV-L25F-00A.

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