A FLVV valve, a combined valve and a CFLVV valve

Abstract

The present invention discloses an FLVV valve, a combined valve and a CFLVV valve, which include a valve base and a flange member. The valve base is fixedly connected to a fuel tank through the flange member. An "O" - shaped sealing ring is also provided between the valve base and the flange member. A large spool assembly and a small spool assembly are arranged on the valve base. The small spool assembly is arranged inside the large spool assembly. A large ventilation hole and a small ventilation hole corresponding to the large spool assembly and the small spool assembly are provided at the upper end of the valve base, and are sealed by setting a sealing assembly; the large spool is relatively sensitive and closes in time, which can greatly reduce the dynamic leakage. The small spool has a strong ability to reopen, which can keep the pressure in the fuel tank relatively low. At the same time, since the corresponding ventilation hole of the small float is small and is inside the large float, the dynamic leakage generated by the hole corresponding to the small float is also low.

Description

Technical Field

[0001] The present invention relates to the technical field of on-vehicle fuel recovery systems, and particularly to an FLVV valve, a combined valve, and a CFLVV valve. Background Art

[0002] Existing fuel tank valves are designed with a single valve core. A moving component moves up and down to open and close the ventilation hole. To ensure a large ventilation volume, the ventilation hole is opened synchronously. Since the single-valve-core valve needs to ensure the re-opening ability of the valve core, that is, under pressure, the valve core can fall from the closed position in time to restore the ventilation ability, the single valve core is made relatively sluggish, resulting in easy escape of fuel from the large ventilation hole, causing serious dynamic leakage; during vehicle driving, the single valve core is prone to premature closing, closing all ventilation channels, resulting in excessive pressure in the fuel tank, so improvement is needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to provide an FLVV valve, a combined valve, and a CFLVV valve to solve the problems existing in the prior art in the above background art.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an FLVV valve includes a valve base and a flange. The valve base is fixedly connected to the fuel tank through the flange. An "O" - shaped sealing ring is also provided between the valve base and the flange. A large valve core assembly and a small valve core assembly are provided on the valve base. The small valve core assembly is arranged inside the large valve core assembly. A large ventilation hole and a small ventilation hole corresponding to the large valve core assembly and the small valve core assembly are provided at the upper end of the valve base, and are sealed by setting a sealing component; the large valve core is relatively sensitive and closes in time, which can minimize dynamic leakage to a great extent. The small valve core has a strong ability to reopen, which can keep the pressure in the fuel tank relatively low. At the same time, since the corresponding ventilation hole of the small float is small and inside the large float, the dynamic leakage generated by the hole corresponding to the small float is also low.

[0005] Further, the flange of the present invention is welded to the fuel tank, which is convenient for disassembly and assembly;

[0006] Further, the large valve core assembly of the present invention includes a large float and a large spring used to balance the gravity of the large float. The large float can move up and down vertically within the range defined by the valve base, and when moving upward, it seals with the large ventilation hole to close the large ventilation hole;

[0007] Further, the small valve core assembly of the present invention includes a small float and a small spring for balancing the gravity of the small float. The small float can move vertically up and down within the limits defined by the valve base and the large float, and when moving upward, it seals with the small vent hole to close the small vent hole.

[0008] Further, the large float and the small float of the present invention have no linkage in movement and no interference, and can move vertically up and down independently.

[0009] Further, the large float and the small float of the present invention share the sealing assembly at the top to respectively seal with the large vent hole and the small vent hole. The sealing assembly is fixed on the large float and moves synchronously with it.

[0010] The beneficial effects of the present invention are as follows: An FLVV valve of the present invention solves the problems existing in the traditional technology. With a double valve core design, it ensures a large ventilation capacity of the fuel tank under normal conditions, greatly reduces fuel dynamic leakage, and at the same time keeps the fuel tank in a low-pressure state for a long time. In addition, it can be normally reopened under high-pressure conditions when both double valve cores are closed to release the pressure in the fuel tank, achieving multiple benefits. Moreover, the structure of the present invention is simple, the transformation cost is low, and the performance is stable, which is worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described below in conjunction with the drawings and embodiments.

[0012] Figure 1 is a schematic structural diagram of the present invention;

[0013] Figure 2 is a schematic structural diagram of the present invention when the large vent hole is closed under harsh working conditions;

[0014] Figure 3 is a schematic structural diagram of the present invention under the condition that both double valve cores are closed;

[0015] Figure 4 is a cross-sectional view of the combined valve of the present invention;

[0016] Figure 5 is another cross-sectional view of the combined valve of the present invention;

[0017] Figure 6 is a cross-sectional view of the first float and the second float of the combined valve of the present invention;

[0018] Figure 7 is a schematic diagram of the top surface of the adapter housing of the combined valve of the present invention;

[0019] Figure 8 is a schematic diagram of the first row of outlets and the second row of outlets of the combined valve of the present invention;

[0020] Figure 9 Schematic diagram of the seal of the combined valve of the present invention;

[0021] Figure 10 Another schematic diagram of the seal of the combined valve of the present invention;

[0022] Figure 11 Another schematic diagram of the seal of the combined valve of the present invention;

[0023] Figure 12 Schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0024] Figure 13 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0025] Figure 14 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0026] Figure 15 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0027] Figure 16 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0028] Figure 17 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0029] Figure 18 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0030] Figure 19 Another schematic diagram of an operation mode of the CFLVV valve of the present invention;

[0031] Figure 20 Schematic diagram of the pressure-holding part of the combined valve of the present invention;

[0032] Figure 21 Another schematic diagram of the pressure-holding part of the combined valve of the present invention.

[0033] In the figure: 1. Valve base, 101. Outer shell, 1011. Hollow part, 1012. Second guide rail, 102. Adapter shell, 1021. First guide rail, 1022. Middle extension ring, 1023. Small extension ring, 2. Flange, 3. "O"-ring, 4. Large vent, 5. Small vent, 6. Sealing assembly, 601. Sealing part, 6011. Large sealing ring, 6012. Middle sealing ring, 6013. Small sealing ring, 602. Sliding part, 7. Large float, 8. Large spring, 9. Small float, 10. Small spring 11. Movable part, 12. Pressure retaining cover, 13. Pressure retaining shell, 14. Valve core accommodating chamber, 15. First connecting port, 16. Second connecting port, 17. Third connecting port, 18. Fourth connecting port, 19. Third inflow channel, 20. Lifting structure, 21. Blocking part. DETAILED DESCRIPTION

[0034] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0035] Example 1

[0036] like Figure 1 、 Figure 2 and Figure 3 The embodiment of an FLVV valve of the present invention shown includes a valve base 1 and a flange 2. The valve base 1 is fixedly connected to the fuel tank through the flange 2. An "O"-shaped sealing ring 3 is also provided between the valve base 1 and the flange 2. A large valve core assembly and a small valve core assembly are provided on the valve base 1. The small valve core assembly is arranged inside the large valve core assembly. The upper end of the valve base 1 is provided with a large vent 4 and a small vent 5 corresponding to the large valve core assembly and the small valve core assembly, and is sealed by providing a sealing assembly 6. The flange 2 is welded to the fuel tank for easy assembly and disassembly; the large valve core assembly includes a large float 7 and a large spring 8 for balancing the gravity of the large float 7. The large float 7 can move vertically up and down within the limited range of the valve base 1, and when moving upward, it seals with the large vent 4 to close the large vent 4; the small valve core assembly includes a small float 9 and a small spring 10 for balancing the gravity of the small float 9. The small float 9 can move vertically up and down within the limited range of the valve base 1 and the large float 7, and when moving upward, it seals with the small vent 5 to close the small vent 5; the large float 7 and the small float 9 have no linkage in movement, and there is no interference in movement, and they can move vertically up and down independently; the large float 7 and the small float 9 share the sealing assembly 6 at the top to respectively seal with the large vent 4 and the small vent 5, and the sealing assembly 6 is fixed to the large float 7 and moves synchronously with it.

[0037] Working principle: Under normal ventilation conditions, both the large float 7 and the small float 9 rest on the valve base 1, and the air flow discharges from the large ventilation hole 4, ensuring a large ventilation capacity for the fuel tank; in relatively harsh working conditions where the vehicle jolts continuously and the fuel tumbles violently in the fuel tank, the large float 7 blocking the large hole is relatively flexible and is prone to floating up when receiving impacts or fuel buoyancy, closing the large ventilation hole 4, which can greatly reduce fuel leakage; at this time, the small float 9 has a reduced flexibility and is less affected by fuel buoyancy and impact forces, and does not close the small ventilation hole 5, that is, the small hole is still exhausting normally, and the pressure inside the fuel tank remains at a relatively low level; the cross-sectional area of the small hole is small and it is inside the large float, so the fuel leakage through the small hole is also very low; the area of the small ventilation hole 5 corresponding to the small float 9 is small, that is, the acting force of air pressure is small, and in the condition where both valve cores are closed and there is high air pressure inside the fuel tank, it can also fall down in time to open the exhaust passage of the small ventilation hole 5 and release the pressure inside the fuel tank.

[0038] Embodiment 2

[0039] This embodiment is mainly a combined valve that can simultaneously achieve the functions of a fuel filling limit valve and a tipping valve, which is applied and installed in the fuel tank. The fluids in the fuel tank are the oil and air in the fuel tank.

[0040] Refer to Figure 4 、 Figure 5 、 Figure 7 and Figure 8 This combined valve of this embodiment includes a valve base 1, a valve core part, and a pressure maintaining part.

[0041] A valve core accommodating cavity 14 is provided inside the valve base 1, and the valve base 1 is provided with a first inflow channel and a second inflow channel that connect the valve core accommodating cavity 14 with the external space of the valve base 1, and the entrance of the second inflow channel is higher than the entrance of the first inflow channel. The first inflow channel is mainly used for the inflow of oil and gas, and the second inflow channel is mainly used for the inflow of gas.

[0042] A large ventilation hole 4 and a small ventilation hole 5 are provided at the upper end of the valve base 1 and are connected to the valve core accommodating cavity 14. The two discharge ports are used for discharging the fluid in the valve core accommodating cavity 14. The pressure maintaining part is provided on the top surface of the valve base 1, and the input end is connected to the small ventilation hole 5, and is used to limit the pressure required for the fluid to discharge from the small ventilation hole 5.

[0043] The valve core part includes a large valve core assembly and a small valve core assembly. The large valve core assembly and the small valve core assembly are respectively vertically slidably connected to the valve core accommodating cavity 14 and are respectively used to open and close the large ventilation hole 4 and the small ventilation hole 5.

[0044] Among them, the switches of the two discharge ports cooperate to achieve the function of the fuel filling limit valve. That is, when the oil continuously surges into the valve core accommodating cavity 14, the gas entering the valve base 1 is discharged through the two discharge ports. At the same time, the large vent hole 4 and the small vent hole 5 are sequentially closed according to the inflow rate of the oil to avoid leakage caused by the discharge of the oil.

[0045] The cooperation between the pressure maintaining part and the large valve core assembly to close the large vent hole 4 makes the fluid in the valve core accommodating cavity 14 have to reach a certain pressure value to flow out from the pressure maintaining part, so as to achieve the function of the flip valve. The flip valve is generally applied when the fuel tank is full of fuel or the vehicle has a certain inclination angle, that is, the large valve core assembly rises to close the large vent hole 4, but the small valve core assembly does not rise and the small vent hole 5 is in the open state. At this time, due to the setting of the pressure maintaining part, the combined valve is in a relatively sealed state as a whole. Due to the volatilization of the oil in the fuel tank or the influence of temperature rise, the pressure inside the fuel tank continues to rise, and the function of the flip valve is required to relieve the pressure. When the pressure in the fuel tank rises to the opening pressure of the pressure maintaining part, the pressure maintaining part can be opened, so that the gas is discharged through the small vent hole 5 and the pressure maintaining part to relieve the internal pressure.

[0046] In this embodiment, different functions can be achieved through the cooperation between the two valve core assemblies without mutual influence. At the same time, different combined valves with different technical requirements can be obtained by separately adjusting the performance of the two valve cores, solving the problem that the two valve cores in the existing combined valve affect each other.

[0047] The specific structure of the combined valve in this embodiment will be further described below:

[0048] In this embodiment, the cross-sectional areas of the large vent hole 4 and the small vent hole 5 are not specifically limited. Based on the functions of the fuel filling limit valve and the flip valve required by the fuel tank, the switch cooperation of the large vent hole 4 and the small vent hole 5 can achieve the function of the fuel filling limit valve, and the switch of the large vent hole 4 and the pressure maintaining part can achieve the function of the flip valve. Therefore, the cross-sectional area of the large vent hole 4 should be larger than that of the small vent hole 5, but it can be actually determined according to the required technical requirements and is not specifically limited here.

[0049] In this embodiment, the valve core portion may further include a sealing assembly 6. The sealing assembly 6 is provided at the top of the valve core accommodating cavity 14 or slides vertically in the valve core accommodating cavity 14, and is used to cooperate with the large valve core assembly to open and close the large ventilation hole 4. A communication channel for communicating the small ventilation hole 5 and the second inflow channel is further provided on the sealing assembly 6, and is used to cooperate with the small valve core assembly to open and close the small ventilation hole 5. Specifically, it can be understood that the purpose of setting the sealing assembly 6 is that when the large valve core assembly rises to the closed position, the sealing assembly 6 needs to close the large ventilation hole 4, and at the same time needs to have a certain cooperation with the small ventilation hole 5 to form a communication channel, so that when the small valve core assembly rises, the communication channel can be closed in cooperation with the sealing assembly 6. That is, the two valve core assemblies respectively open and close the two discharge ports through the same sealing assembly 6.

[0050] A sealing assembly 6 is further provided in the valve base 1, which is used to cooperate with the two valve core assemblies respectively to open and close the two discharge ports, improving the sealing performance of the valve. The setting method of the sealing assembly 6 can be sliding in the valve core accommodating cavity 14, or fixedly arranged at the two discharge ports. The setting method is flexible and changeable, and different layout methods can be adopted according to different technical requirements. At the same time, after a long time of use, when the sealing effect of the valve is insufficient, only the sealing assembly 6 needs to be replaced.

[0051] In this embodiment, on the basis of the foregoing components, the combined valve may further include a flange 2, which is used to connect with an external pipeline to guide the gas discharged from the two discharge ports to the external pipeline for treatment. Among them, the flange 2 can be sleeved on the valve base 1 and cooperate with the top surface of the valve base 1 to form a fluid discharge chamber. At this time, the large ventilation hole 4 and the pressure maintaining portion are located in this fluid discharge chamber, and are used to guide the fluid discharged from the large ventilation hole 4 and the pressure maintaining portion. The connection method between the flange 2 and the valve base 1 can be welding or other fixed connection methods, and a sealing ring 3 needs to be further used for sealing when necessary.

[0052] In this embodiment, the valve base 1 may specifically include a housing 101 with an upward opening and an adapter housing 102 with a downward opening. The housing 101 is sleeved on the lower end of the adapter housing 102 and fixedly connected to the adapter housing 102. The inner wall surface of the adapter housing 102 and the inner cavity bottom surface of the housing 101 cooperate to form a valve core accommodating cavity 14.

[0053] Among them, at least one first connection port 15 is opened on the housing of the housing 101. The first connection port 15, the outer wall surface of the adapter housing 102 and the inner wall surface of the housing 101 cooperate to form a third inflow channel 19 communicating with the valve core accommodating cavity 14. That is, after the oil fluid enters the interior of the housing 101 through the first connection port 15, under the action of gravity, it can flow to the inner cavity bottom surface of the housing 101 through the gap between the housing 101 and the adapter housing 102, so as to gradually fill the valve core accommodating cavity 14 and provide buoyancy for the large valve core assembly and the small valve core assembly to rise.

[0054] The housing of the adapter housing 102 is provided with at least one second connection port 16 communicating with the valve core accommodating cavity 14. The first connection port 15 and the second connection port 16 cooperate to form a first inflow channel. The position of the second connection port 16 generally needs to be higher than that of the first connection port 15 to prevent the oil fluid flowing in through the first connection port 15 from entering the valve core accommodating cavity 14 through the second connection port 16. When the pressure in the fuel tank increases, the gas will enter the valve core accommodating cavity 14 through the first inflow channel and be discharged through the large vent hole 4 and the small vent hole 5 at the top to reduce the pressure in the fuel tank.

[0055] The outer housing 101 is provided with at least one third connection port 17, and the housing of the adapter housing 102 is provided with at least one fourth connection port 18 communicating with the valve core accommodating cavity 14. The third connection port 17, the fourth connection port 18 and the communication channel of the sealing component 6 cooperate to form a second inflow channel. The heights of both the third connection port 17 and the fourth connection port 18 need to be higher than that of the first inflow channel. Preferably, they are close to the tops of the outer housing 101 and the adapter housing 102, so that when the oil fluid level in the valve core accommodating cavity 14 is relatively high, the gas in the fuel tank can still flow into the valve core accommodating cavity 14 through the second inflow channel and form a pressure on the pressure maintaining part through the small vent hole 5 to open the pressure maintaining part and discharge the gas.

[0056] Furthermore, the first connection port 15, the second connection port 16, the third connection port 17 and the fourth connection port 18 can be through holes provided on the outer housing 101 or the adapter housing 102 respectively. Their specific sizes and shapes can be determined according to actual requirements and are not specifically limited herein.

[0057] In this embodiment, the large valve core assembly corresponds to the large vent hole 4 and specifically includes a large float 7 and a large spring 8. The large float 7 is slidably connected to the valve core accommodating cavity 14. Two ends of the large spring 8 are respectively connected to the large float 7 and the bottom surface of the valve core accommodating cavity 14. A accommodating groove with an opening facing a certain direction can be formed in the large float 7 so that the large spring 8 can extend into the large float 7 to be connected to the large float 7, thereby further reducing the volume of the large valve core assembly.

[0058] The small valve core assembly corresponds to the small vent hole 5 and specifically includes a small float 9, a small spring 10 and a movable part 11. The small float 9 is slidably connected to the valve core accommodating cavity 14. Two ends of the small spring 10 are respectively connected to the small float 9 and the bottom surface of the valve core accommodating cavity 14. The movable part 11 is movably connected to the top surface of the small float 9 and is used to cooperate with the sealing component 6 to open and close the small vent hole 5. At the same time, the combination of the movable part 11 and the small float 9 can make the sealed small vent hole 5 easier to open. Similarly, an accommodating groove with an opening downward can also be formed in the small float 9 for connecting with the small spring 10 to reduce the volume of the small valve core assembly.

[0059] Among them, the elastic forces of the large spring 8 and the small spring 10 can be determined according to the gravity of the float and the lifting force when the float rises. In other embodiments, the two springs can also be elastic elements such as elastic rubber, and no specific limitation is made here.

[0060] Preferably, the large float 7 can be an annular float, and the small float 9 can be a cylindrical float or an annular float with a diameter smaller than the inner diameter of the large float 7. After being slidably connected to the valve core accommodation groove, the large float 7 is in a state of sleeving the small float 9, achieving full utilization of the internal space of the combined valve and further reducing the volume of the combined valve. At this time, the small vent hole 5 can be several discharge holes provided on the top surface of the inner cavity of the adapter shell 102, and the large vent hole 4 can be several discharge holes surrounding the small vent hole 5.

[0061] See Figure 6 , in this embodiment, the large float 7 and the small float 9 are slidably connected to the valve core accommodation cavity 14. The specific connection method is as follows:

[0062] Several vertically arranged first guiding slide rails 1021 can be provided on the inner wall surface of the adapter shell 102. Corresponding first sliding grooves are provided on the large float 7, and the large float 7 is slidably connected to the first guiding slide rails 1021 through the first sliding grooves.

[0063] The sliding mode of the small float 9 is more complex. Since the large float 7 and the small float 9 do not affect each other, but the small float 9 needs to be arranged inside the inner circle of the large float 7, a hollow part 1011 needs to be provided on the bottom surface of the inner cavity of the outer shell 101. The hollow part 1011 and the bottom surface of the inner cavity cooperate to form a vertical guiding groove, and several vertically arranged second guiding slide rails 1012 are provided on the inner wall surface of the hollow part 1011. Corresponding second sliding grooves are provided on the small float 9, and the small float 9 is slidably connected to the second guiding slide rails 1012.

[0064] During actual implementation, the movement amount of the valve core assembly can be limited by designing the fitting clearance at the sliding connection, and at the same time, the contact area between the valve core assembly and the contacting components during the movement process can be reduced, reducing the friction force between each other, making the valve core assembly more flexible during the movement process and easier to open and close the corresponding discharge port.

[0065] Further, the slide rails and the sliding grooves can also be interchanged. Taking the large float 7 as an example, the first sliding groove can be provided on the inner wall surface of the adapter shell 102, and the first guiding slide rail 1021 can be provided on the large float 7.

[0066] In this embodiment, the pressure-holding part specifically includes a pressure-holding shell 13 and a pressure-holding cover 12. An accommodation space is provided inside the pressure-holding shell 13, and an inflow hole and a discharge hole communicating with the accommodation space are further provided on the pressure-holding shell 13. The pressure-holding shell 13 is arranged on the top surface of the valve base 1, and the inflow hole is communicated with the small vent hole 5. The pressure-holding cover 12 is slidably connected to the accommodation space and is used to open and close the inflow hole. That is, the pressure-holding cover 12 presses on the inflow hole of the accommodation space by its own gravity to close the inflow hole. After the gas pressure in the valve core accommodation cavity 14 reaches a value that can offset the gravity of the pressure-holding cover 12, the pressure-holding cover 12 can be pushed to rise, so that the gas can enter the accommodation space through the inflow hole and be discharged through the discharge hole to the fluid discharge chamber formed by the flange 2.

[0067] Embodiment Three

[0068] See Figures 9 to 11 , on the basis of the above-mentioned Embodiment Two, several preferred implementation manners of the sealing component 6 are further described in this embodiment:

[0069] In this embodiment, the sealing component 6 can be specifically divided into two setting manners. The first is to be arranged on the inner cavity top surface of the valve core accommodation cavity 14, and the second is to be slidably connected inside the valve core accommodation cavity 14.

[0070] First, the first case is described as follows:

[0071] The sealing component 6 can specifically be several sealing members 601 respectively sleeved at the large vent hole 4 and the small vent hole 5, and each sealing member 601 extends a sealing ring into the valve core accommodation cavity 14. The sealing rings can respectively connect the valve core accommodation cavity 14 to the large vent hole 4 or the small vent hole 5. At this time, when the large float 7 rises, it can contact and seal with the sealing ring corresponding to the large vent hole 4, separating the valve core accommodation cavity 14 from the large vent hole 4 to achieve the closing of the large vent hole 4. Similarly, when the small float 9 rises, it can contact and seal with the sealing ring corresponding to the small vent hole 5, separating the valve core accommodation cavity 14 from the small vent hole 5 to achieve the closing of the small vent hole 5.

[0072] Next, the second case is described. There are many implementable manners for this case. Therefore, based on the situation in the above-mentioned Embodiment One where the large float 7 is sleeved on the small float 9 and the centers of the large vent hole 4 and the small vent hole 5 are the same, some examples are given for illustration to facilitate understanding, as follows:

[0073] The overall idea is that the sealing component 6 includes a sliding member 602 and a sealing member 601. The sliding member 602 is used for sliding connection with the valve core accommodating cavity 14, and the sealing member 601 is arranged on the sliding member 602 and is used to cooperate with two floats to switch two discharge ports. Among them, the sliding member 602 and the sealing member 601 can be separated and assembled together, or integrally formed. The structure of the sliding member 602 part is relatively conventional. The following is mainly an explanation of the specific arrangement method of the sealing member 601:

[0074] Embodiment 1: The sealing member 601 is an annular sealing member 601, and the inner ring of the annular sealing member 601 corresponds to the small vent hole 5. A large sealing ring 6011 and a medium sealing ring 6012 are provided on the upper end surface of the annular sealing member 601.

[0075] Among them, the radius of the large sealing ring 6011 needs to be greater than the maximum radius of the large vent hole 4, and the radius of the medium sealing ring 6012 needs to be less than the minimum radius of the large vent hole 4 and the maximum radius of the small vent hole 5. Such a setting is to ensure that when the sealing member 601 is in the closed position, it can be closely attached to the inner and outer wall surfaces of the adapter housing 102 located inside the large vent hole 4 to achieve the sealing of the large vent hole 4.

[0076] After sealing the large vent hole 4, the small vent hole 5 is communicated with the valve core accommodating cavity 14 through the inner ring of the annular sealing member 601. In order to seal the small vent hole 5, a small sealing ring 6013 needs to be provided on the lower end surface of the annular sealing member 601, and the radius of the small sealing ring 6013 needs to be greater than the inner ring radius of the annular sealing member 601. The small sealing ring 6013 can contact the top surface of the small float 9 when the small float 9 rises and achieve the sealing of the small vent hole 5.

[0077] Embodiment 2: This embodiment is a modification of the above Embodiment 1. The sealing member 601 is also an annular sealing member 601. The setting methods of the large sealing ring 6011 and the small sealing ring 6013 remain unchanged, and the medium sealing ring 6012 is removed. Specifically, a medium extension ring 1022 is provided on the inner cavity top surface of the adapter housing 102 on the wall surface between the large vent hole 4 and the small vent hole 5, and the lower end of the medium extension ring 1022 is used to contact the upper end surface of the annular sealing member 601. So that when the annular sealing member 601 moves to the closed position, it can cooperate with the large sealing ring 6011 to achieve the sealing of the large vent hole 4, and at the same time can cooperate with the inner ring of the annular sealing member 601 to achieve the communication between the small vent hole 5 and the valve core accommodating cavity 14. The sealing method of the small sealing ring 6013 is the same as that in Embodiment 1 and will not be elaborated.

[0078] Embodiment 3: This embodiment is also a modification of Embodiment 1 above. The seal 601 is also an annular seal 601. The arrangement of the middle seal ring 6012 and the small seal ring 6013 remains unchanged, and the large seal ring 6011 is removed. Specifically, a large extension ring is provided on the inner wall surface of the top surface of the adapter housing 102 outside the large vent hole 4. The lower end of the large extension ring is used to contact the upper surface of the annular seal 601. When the annular seal 601 moves to the closed position, it cooperates with the middle seal ring 6012 to seal the large vent hole 4. The sealing method of the middle seal ring 6012 and the small seal ring 6013 for the small vent hole 5 is the same as that in Embodiment 1 and will not be elaborated.

[0079] Embodiment 4: This embodiment is also a modification of Embodiment 1 above. The seal 601 is also an annular seal 601. The arrangement of the small seal ring 6013 remains unchanged, and the large seal ring 6011 and the middle seal ring 6012 are removed. Specifically, a large extension ring is provided on the inner wall surface of the top surface of the adapter housing 102 outside the large vent hole 4. The lower end of the large extension ring is used to contact the upper surface of the annular seal 601. A middle extension ring 1022 is provided on the inner wall surface of the top surface of the adapter housing 102 between the large vent hole 4 and the small vent hole 5. The lower end of the middle extension ring 1022 is also used to contact the upper surface of the annular seal 601. When the annular seal 601 moves to the closed position, the large extension ring and the middle extension ring 1022 cooperate with the annular seal 601 to seal the large vent hole 4. The sealing method of the small seal ring 6013 for the small vent hole 5 is the same as that in Embodiment 1 and will not be elaborated.

[0080] Embodiment 5: This embodiment is a modification of Embodiment 1 above. The seal 601 is also an annular seal 601. The large seal ring 6011, the middle seal ring 6012 and the small seal ring 6013 are all removed. Specifically, a large extension ring is provided on the inner wall surface of the top surface of the adapter housing 102 outside the large vent hole 4. The lower end of the large extension ring is used to contact the upper surface of the annular seal 601. A small extension ring 1023 is provided on the inner wall surface of the top surface of the adapter housing 102 between the large vent hole 4 and the small vent hole 5. The diameter of the upper end of the small extension ring 1023 is larger than the inner diameter of the annular seal 601, and the diameter of the lower end is smaller than the inner diameter of the annular seal 601, that is, the outer wall of the small extension ring 1023 is used to contact the inner ring of the annular seal 601. When the annular seal 601 moves to the closed position, the cooperation between the annular seal 601 and the outer wall of the small extension ring 1023 and the large extension ring achieve the sealing of the large vent hole 4. The lower end of the small extension ring 1023 cooperates with the upper surface of the small float 9 to seal the small vent hole 5.

[0081] Of course, in other embodiments, the sealing component 6 can also be arranged on the large float 7 and the small float 9, directly cooperating with the large vent hole 4 and the small vent hole 5 for sealing. There are many specific implementation manners, which are not specifically limited herein.

[0082] Embodiment 4

[0083] Refer to Figure 5 , this embodiment is a further improvement on the structure of the third inflow channel 19 in the second embodiment above, which is specifically as follows:

[0084] This embodiment takes the inner side wall of the outer shell 101 and the outer side wall of the adapter shell 102 being circular as an example, but the setting manners of the outer shell 101 and the adapter shell 102 can be various, which are not specifically limited herein.

[0085] The overall idea is to set a barrier member 21 on the third inflow channel 19 to limit the flow area of the third inflow channel 19. When the inflow pressure of the oil is constant, the oil flowing into the valve core accommodation cavity 14 will decrease.

[0086] Specifically, the barrier member 21 can be an annular barrier member 21 arranged on the inner side wall of the outer shell 101. The inner diameter of the annular barrier member 21 is larger than the outer diameter of the outer side wall of the adapter shell 102, so as to form a gap between the annular barrier member 21 and the adapter shell 102. The cross-sectional area of this gap is the flow area of the third inflow channel 19 here. The inner diameter of the annular barrier member 21 can be changed according to the required flow area size, or holes can be directly opened on the annular barrier member 21 to change the flow area. There are many specific implementation manners, which are not specifically limited herein.

[0087] In another implementation manner, the barrier member 21 can be an annular barrier member 21 arranged on the outer side wall of the adapter shell 102. The outer diameter of the annular barrier member 21 is smaller than the inner diameter of the inner side wall of the outer shell 101, so as to form a gap between the annular barrier member 21 and the outer shell 101. The cross-sectional area of this gap is the flow area of the third inflow channel 19 here. The outer diameter of the annular barrier member 21 can be changed according to the required flow area size, or holes can be directly opened on the annular barrier member 21 to change the flow area. There are many specific implementation manners, which are not specifically limited herein.

[0088] In another implementation manner, the barrier member 21 can be an annular barrier member 21 whose outer circle and inner circle are respectively connected to the inner side wall of the outer shell 101 and the outer side wall of the adapter shell 102. Holes are directly opened on the annular barrier member 21, and the flow area can be changed by the area and number of the holes. There are many specific implementation manners such as the shape and arrangement manner of the holes, which are not specifically limited herein.

[0089] In other embodiments, it may also be a number of barrier members 21 provided on the inner sidewall of the outer shell 101, or on the outer sidewall of the adapter shell 102, or connected to both the outer shell 101 and the adapter shell 102 at the same time. The shape of the barrier members 21 can also be diverse. The cross-sectional area of the gap formed between the number of barrier members 21 and the adapter shell 102 is the flow area of the third inflow channel 19 here.

[0090] In this embodiment, a barrier member 21 is provided on the third inflow channel 19. When a large amount of fluid enters the valve core accommodating cavity 14 through the third inflow channel 19, it can play a role in relatively isolating the external fluid from the internal valve core, producing a certain blocking effect on the fluid, and preventing the valve core assembly from closing prematurely due to a large influx of fluid. In addition, under harsh working conditions such as large shaking amplitude, the fluid will enter the valve core accommodating cavity 14 through the third inflow channel 19 due to shaking. At this time, the design of the barrier member 21 will also relatively isolate the fluid from the valve core accommodating cavity 14, and less fluid will enter the valve core accommodating cavity 14, reducing the impact of working conditions such as shaking on the valve core assembly. At the same time, less fluid enters the valve core accommodating cavity 14, and the probability of fluid leakage from the valve base 1 during the dynamic process will be greatly reduced.

[0091] Embodiment Five

[0092] See Figure 5 , this embodiment is a further improvement on the bottom surface structure of the outer surface of the outer shell 101 in the second embodiment above, specifically as follows:

[0093] The main purpose of the improvement scheme designed in this embodiment is to slow down the impact of the oil on the small float 9 and prevent the small float 9 from rising prematurely due to the impact of the oil, resulting in the premature closing of the small vent hole 5.

[0094] Therefore, in this embodiment, the problem of the small float 9 rising due to the impact of the oil is alleviated by raising the minimum height of the small float 9.

[0095] Specifically, a raising structure 20 can be provided on the bottom surface of the inner cavity of the outer shell 101. The raising structure 20 is matched with the position of the small float 9, and the height can be determined according to the specific technical requirements for the small float 9. The hollow member 1011 is installed on the top surface of the raising structure 20. In this way, the lowest height of the small float 9 is the top surface of the raising structure 20, and the oil needs to rise to the top surface of the raising structure 20 to have an impact on the small float 9.

[0096] The elevation structure 20 can be a spacer block, which can be a hollow structure, thereby further reducing the overall weight of the combination valve. The elevation structure 20 can also be a depression provided on the bottom surface of the outer surface of the housing 101, forming a depression cavity, which is a protrusion on the bottom surface of the inner cavity from the perspective of the inner cavity. Installing the hollow member 1011 on this protrusion can also raise the lowest position of the small float 9. Compared with directly setting the elevation structure 20 in the inner cavity, the setting of the depression cavity can cooperate with the bottom surface of the housing 101 to form an air cavity, so as to protect the small valve core assembly when there is an oil impact.

[0097] Both the fuel filling limit valve and the tilting valve have a theoretical closing height. That is, when the liquid level inside the fuel tank rises to a certain height, the floats inside the fuel filling limit valve and the tilting valve will rise until the exhaust passage is closed. However, when the liquid level rises to close the exhaust passage of the fuel filling limit valve, it is necessary to ensure that the tilting valve does not close, because at this time, the exhaust passage of the tilting valve is needed to relieve the pressure inside the fuel tank. Therefore, generally, the closing height of the tilting valve needs to be designed relatively higher to ensure that when the fuel filling limit valve is closed, the tilting valve is still in the open state.

[0098] In this embodiment, by setting an upward concave groove on the bottom of the outer surface of the housing 101 or directly setting a spacer block in the inner cavity, this method is an elevation design, which raises the lowest sliding position of the small float 9, so that the fluid entering the valve core accommodating cavity 14 needs to reach a certain height before the small float 9 can receive sufficient buoyancy and rise, avoiding the situation that the small float 9 rises prematurely and closes the small vent hole 5. At the same time, this elevation design can also ensure that when the fuel filling limit valve function is closed, the tilting valve function is still in the open state, that is, after the large vent hole 4 is closed, the small vent hole 5 is not closed. In addition, since the small float 9 is at a higher position, when in working conditions such as shaking, the fluid that can enter the valve core accommodating cavity 14 and impact the small float 9 will be relatively less, which also improves the leakage problem in the dynamic situation. In addition, the elevation design is set as an open groove, which can form an air cavity at the groove, cooperate with the bottom surface of the housing 101 to protect the small valve core assembly, and reduce the impact of oil.

[0099] Embodiment Six

[0100] See Figure 4 , this embodiment further illustrates the specific structure of the pressure maintaining part in the second embodiment above, as follows:

[0101] The design idea of the pressure-holding part is to design a component at the small vent hole 5 that requires a certain pressure to open, so that when the pressure in the fuel tank reaches a certain value, the gas will be discharged from the small vent hole 5. Therefore, the pressure-holding part is specifically set as the pressure-holding shell 13 and the pressure-holding cover 12. The pressure-holding shell 13 is used as a connecting part for connecting the small vent hole 5, with an accommodation space left inside. The pressure-holding cover 12 is arranged in this accommodation space and is used to cover the inlet connected to the accommodation space and the small vent hole 5, and maintain the closure of the inlet by its own gravity. When the pressure in the valve core accommodation cavity 14 is greater than or can offset the weight of the pressure-holding cover 12, the pressure-holding cover 12 is lifted, and the gas can be discharged.

[0102] Furthermore, the pressure-holding cover 12 can be made of a material with a relatively large weight, or can be set in a way of combining a lightweight material with an elastic part. When using an elastic part, the two ends of the elastic part are respectively connected to the upper end of the pressure-holding cover 12 and the top surface of the accommodation space, and the closing force required for the inlet is formed by the cooperation of the elastic force of the elastic part and the gravity of the pressure-holding cover 12.

[0103] See Figure 20 , when the height of the fluid discharge chamber formed by the cooperation of the valve base 1 and the flange part 2 is relatively low, the thickness of the pressure-holding shell 13 can be designed to be thinner, then the width of the pressure-holding shell 13 will become larger. In order to avoid interference of the pressure-holding shell 13 being too wide with the large vent hole 4 and reducing the flow area of the large vent hole 4, an extension pipe can be arranged at the bottom of the pressure-holding shell 13. The two ends of the extension pipe are respectively connected to the inlet and the small vent hole 5 to lift the height of the bottom surface of the pressure-holding shell 13 so that it will not interfere with the top surface of the adapter shell 102, and thus will not affect the large vent hole 4.

[0104] See Figure 21 , when the height of the fluid discharge chamber is relatively high, the width of the pressure-holding shell 13 can be designed to be less than the minimum diameter of the large vent hole 4. In this way, the extension pipe can be not arranged, and the inlet can be directly connected to the small vent hole 5. The volume of the accommodation space of this design is relatively small, and the volume of the pressure-holding cover 12 that can be accommodated is also relatively small. Therefore, the way of combining the pressure-holding cover 12 with the elastic part is more suitable for this design.

[0105] Embodiment Seven

[0106] See Figure 4 and Figure 18 , this embodiment further explains the specific structure of the moving part 11 in the second embodiment above, as follows:

[0107] The movable part 11 is assembled with the small float 9, and the small float 9 can perform a certain vertical axial movement within the valve core accommodation cavity 14. The assembly method of the movable part 11 and the small float 9 can be a "hinge type" rotating shaft structure, enabling the movable part 11 to perform a rotational movement along the axis on one side; it can also be a "slant piece type" structure. After the movable part 11 is assembled on the small float 9, its top surface forms a certain angle with the horizontal plane.

[0108] Furthermore, the movable part 11 can be rotationally connected to the top surface of the small float 9 through a rotating shaft. Under the action of the small float 9 and its own gravity, it forms a certain angle with the axis, and forms an opening with the communication channel formed by the small ventilation hole 5 and the sealing component 6 from one side for breathing and exhausting gas. Under high-pressure conditions, a ventilation channel is formed, thereby releasing the pressure inside the fuel tank.

[0109] Among them, the movable part 11 is provided to ensure that when the entire valve core, that is, the large valve core assembly and the small valve core assembly, are both in the closed position, and the large ventilation hole 4 and the small ventilation hole 5 are both closed, the fuel tank may be under a certain pressure in some cases. At this time, at least one of the two valve cores needs to be opened in a timely manner to relieve the pressure inside the fuel tank. Since P = F / S, it can be known that when F is constant, the larger S is, the smaller P is. That is to say, when there is a relatively high pressure inside the fuel tank, due to the relatively large cross-sectional area S of the large ventilation hole 4 usually, it will only open under a relatively low pressure. At this time, it is necessary to open through the small ventilation hole 5 in a timely manner to relieve the pressure inside the fuel tank. The combination of the movable part 11 and the small float 9 is to make it easier to open after being sealed with the small hole, realizing the pressure relief inside the fuel tank. Therefore, the combined structure of the movable part 11 and the small float 9 can be diverse, and its purpose is to achieve the function of making the small hole easier to reopen. Or the movable part 11 can be cancelled, and some structures can be made on the small float 9 to achieve the function of being easy to reopen.

[0110] Embodiment Eight

[0111] A CFLVV valve in this embodiment includes the combined valve in any one of the above-mentioned Embodiments Two to Seven. In this embodiment, through the cooperation between the two valve core components, the functions of the fuel filling limit valve and the flip valve can be realized without mutual interference. At the same time, different combined valves with different technical requirements can be obtained by respectively adjusting the performance of the two valve cores, solving the problem that the two valve cores in the existing combined valve affect each other.

[0112] The operation mode of the CFLVV under various working conditions will be described below:

[0113] 1. Refer to Figure 12, the fuel tank realizes the exhaust function of the refueling limit valve through the combination valve. This situation generally occurs when the fuel inside the fuel tank is not full, or it can be understood that the fuel inside the fuel tank does not overly submerge the large float 7 and the small float 9. At this time, both floats are in the dropped state, and the sealing component 6 does not form a seal with the large vent hole 4 and the small vent hole 5. At this time, the gas inside the fuel tank can be discharged through the large vent hole 4, and the combination valve functions as a refueling limit valve.

[0114] 2. Refer to Figures 13 to 15 , the combination valve realizes the refueling limit function of the refueling limit valve. The refueling limit function is the refueling cut-off function. Generally, there are two situations for the fuel tank to cut off refueling. But generally speaking, when the large air flow channel in the refueling limit valve is closed or narrowed, and refueling continues, it will cause the pressure inside the fuel tank to rise sharply, and the liquid level on the refueling pipe side will also rise sharply, resulting in refueling cut-off.

[0115] 2.1 When the first connection port 15 opened on the side of the base is relatively high, during refueling, when the fuel liquid level rises to the position of the first connection port 15, the fuel will instantaneously enter the valve core accommodation cavity 14 through the third inflow channel 19. At this time, the gravity of the whole formed by the large float 7 and the sealing component 6 slidably connected in the valve core accommodation cavity 14 may be less than the buoyancy of the fuel plus the elastic force of the spring 8. Therefore, the large float 7 will drive the sealing component 6 to move upward until the sealing component 6 touches the inner cavity top surface of the adapter shell 102, and the sealing component 6 will block the large vent hole 4. In this way, the large exhaust channel in the combination valve will be closed, resulting in a sharp rise in the pressure inside the fuel tank, and then refueling cut-off occurs.

[0116] 2.2 Another situation where the combination valve has the function of a refueling limit valve. When the first connection port 15 opened on the base is relatively low, during refueling, when the liquid level submerges the lower edge of the first connection port 15, as the fuel liquid level continues to rise, the ventilation window will become smaller and smaller, and the cross-sectional area of the air flow channel will also become smaller and smaller. In this way, the pressure inside the fuel tank will continue to rise as the air flow channel decreases until the pressure inside the fuel tank rises to a certain level, and then refueling cut-off occurs.

[0117] 3. Refer to Figure 16 and Figure 17, the large vent hole 4 in the combination valve is closed, and the pressure in the fuel tank is relieved by the function of the flip valve. This situation generally occurs when the fuel tank is full or when some vehicles are at a certain inclination, causing the large float 7 inside the valve core to rise with the sealing component 6, closing the large vent hole 4. However, due to the gravity of the small float 9 plus the moving part 11 minus the elastic force of the small spring 10, the overall difference is relatively large, and there is still a relatively large downward gravity. Therefore, the overall composed of the small float 9 and the moving part 11 does not rise. At this time, the communication channel of the sealing component 6 for communicating with the small vent hole 5 is still open. However, since there is a pressure maintaining part above the small vent hole 5 corresponding to the adapter housing 102, the combination valve as a whole is still in a relatively sealed state at this time. At this time, due to the continuous volatilization of the fuel inside the fuel tank or the influence of rising temperature, the pressure inside the fuel tank will continue to rise. This is when the function of the flip valve needs to be exerted to relieve the increased pressure inside the fuel tank in a timely manner. When the pressure inside the fuel tank rises high enough to blow up the pressure maintaining cover 12, the pressure inside the fuel tank will decrease accordingly, and the air flow will enter the valve core accommodation cavity 14 through the second inflow channel on the side of the outer housing 101, then pass through the communication channel on the sealing component 6 to the small vent hole 5 on the adapter housing 102, then pass through the exhaust channel designed inside the pressure maintaining housing 13, and finally be discharged through the fluid discharge chamber.

[0118] 4. Refer to Figure 15 , when the vehicle is in motion, there may be violent shaking or a certain inclination, and the oil in the fuel tank will also shake violently accordingly. At this time, it is necessary for the large vent hole 4 and the small vent hole 5 inside the combination valve to be sealed in a timely manner to prevent the oil in the fuel tank from leaking out through the discharge port inside the combination valve. The large float 7 and the sealing component 6 will rise in a timely manner with the shaking to close the large vent hole 4 on the adapter housing 102, and then the second and the moving component will also rise in a timely manner to close the corresponding communication channel of the sealing component 6. In this way, the entire valve core will form a sealed state to prevent dynamic fuel leakage.

[0119] During the shaking of the fuel tank, the valve core of the combination valve needs to be closed in a timely manner to prevent dynamic fuel leakage. This requires the valve core of the combination valve to be relatively flexible and can be closed in a timely manner during shaking. Therefore, for the combination valve with two mutually independent valve cores, the flexibility of the valve core is easier to adjust. Because the two valve cores inside are one on the outside and one on the inside, and the two valve cores have no direct connection, the ratio of the float to the spring of the two valve cores can be adjusted separately, and the flexibility of each valve core can be adjusted separately to achieve the purpose of preventing fuel leakage.

[0120] 5. Refer to Figure 19, during the fuel sloshing process mentioned above, the two valve cores can be closed in time to prevent dynamic fuel leakage. At the same time, after the valve cores are closed in time, the valve cores need to not only be able to close in time but also be able to open in time during the fuel sloshing process. Because when the valve cores are closed in time, the inside of the fuel tank will be in a completely sealed state, so the internal pressure will increase accordingly. At this time, the flip valve function of the combination valve needs to be able to open in time to relieve the pressure inside the fuel tank.

[0121] From P = F / S, it can be known that when F is constant, the larger the contact area S is, the smaller P is. Since the area of the large ventilation hole 4 corresponding to the large float 7 inside the valve core and the sealing component 6 is relatively large, when there is a certain pressure inside the fuel tank, it is very difficult for the large valve core component to open in time for pressure relief. Therefore, at this time, the small hole corresponding to the small float 9 inside and the movable component needs to be able to open in time for pressure relief function.

[0122] Inspired by the ideal embodiments of the present invention described above, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An FLVV valve, characterized in that: The invention comprises a valve base (1) and a flange (2), wherein the valve base (1) is fixedly connected to the fuel tank via the flange (2), an O-ring (3) is further provided between the valve base (1) and the flange (2), a large valve core assembly and a small valve core assembly are provided on the valve base (1), the small valve core assembly is provided inside the large valve core assembly, a large vent hole (4) and a small vent hole (5) corresponding to the large valve core assembly and the small valve core assembly are provided at the upper end of the valve base (1), and the vent hole is sealed by providing a sealing assembly (6); the valve base (1) comprises an outer shell (101) with an opening facing upward and a transfer shell (102) with an opening facing downward; the outer shell (101) is sleeved on the lower end of the transfer shell (102) and is fixedly connected to the transfer shell (102); The inner wall surface of the adapter shell (102) cooperates with the bottom surface of the outer shell (101) to form a valve core accommodating cavity (14); at least one first connecting port (15) is formed on the shell of the outer shell (101); The housing of the adapter shell (102) is provided with at least one second connection port (16) communicating with the valve core accommodating cavity (14), and the first connection port (15) and the second connection port (16) cooperate to form a first inflow channel; At least one third connection port (17) is provided on the outer shell (101), and at least one fourth connection port (18) communicating with the valve core accommodating chamber (14) is provided on the shell of the adapter shell (102), and the third connection port (17), the fourth connection port (18) and the communication channel of the sealing assembly (6) cooperate to form a second inflow channel; The first connecting port (15), the outer wall surface of the adapter shell (102), and the inner wall surface of the outer shell (101) cooperate to form a third inflow channel (19) connected to the valve core accommodating cavity (14).

2. The FLVV valve according to claim 1, characterized in that: The flange (2) is welded to the fuel tank.

3. The FLVV valve according to claim 1, characterized in that: The large valve core assembly includes a large float (7) and a large spring (8) for balancing the gravity of the large float (7). The large float (7) can move vertically up and down within a limited range of the valve base (1), and when moving upward, it seals with the large vent hole (4) to close the large vent hole (4).

4. The FLVV valve according to claim 3, characterized in that: The small valve core assembly includes a small float (9) and a small spring (10) for balancing the gravity of the small float (9). The small float (9) can move vertically up and down within the limited range of the valve base (1) and the large float (7), and when moving upward, it seals with the small vent hole (5) to close the small vent hole (5).

5. The FLVV valve according to claim 4, characterized in that: The large float (7) and the small float (9) have no movement linkage, no movement interference, and can independently move up and down vertically.

6. The FLVV valve according to claim 4, characterized in that: The large float (7) and the small float (9) share the sealing assembly (6) at the top to respectively seal the large vent hole (4) and the small vent hole (5). The sealing assembly (6) is fixed on the large float (7) and moves synchronously with the large float (7).

7. A combination valve, characterized in that: The invention comprises a valve base (1) and a flange (2), wherein the valve base (1) is fixedly connected to the fuel tank via the flange (2), and an "O"-shaped sealing ring (3) is further provided between the valve base (1) and the flange (2); a valve core accommodating cavity (14) is provided in the valve base (1), a large valve core assembly and a small valve core assembly are respectively slidably connected in the valve core accommodating cavity (14), and the small valve core assembly is arranged inside the large valve core assembly; a large vent hole (4) and a small vent hole (5) corresponding to the large valve core assembly and the small valve core assembly are provided at the upper end of the valve base (1), and are sealed by providing a sealing assembly (6); It also includes a pressure maintaining portion, which is provided on the valve base (1) and has an input end in communication with the small vent hole (5) and is used to limit the pressure required to discharge the fluid from the small vent hole (5); The valve base (1) comprises an outer shell (101) with an upward opening and an adapter shell (102) with a downward opening; the outer shell (101) is sleeved on the lower end of the adapter shell (102) and is fixedly connected to the adapter shell (102); The inner wall surface of the adapter shell (102) cooperates with the bottom surface of the outer shell (101) to form the valve core accommodating cavity (14); at least one first connecting port (15) is formed on the shell of the outer shell (101); The housing of the adapter shell (102) is provided with at least one second connection port (16) communicating with the valve core accommodating cavity (14), and the first connection port (15) and the second connection port (16) cooperate to form a first inflow channel; At least one third connection port (17) is provided on the outer shell (101), and at least one fourth connection port (18) communicating with the valve core accommodating chamber (14) is provided on the shell of the adapter shell (102), and the third connection port (17), the fourth connection port (18) and the communication channel of the sealing assembly (6) cooperate to form a second inflow channel; The first connecting port (15), the outer wall surface of the adapter shell (102), and the inner wall surface of the outer shell (101) cooperate to form a third inflow channel (19) connected to the valve core accommodating cavity (14).

8. The combination valve according to claim 7, characterized in that: The pressure-maintaining portion includes a pressure-maintaining shell (13) and a pressure-maintaining cover (12); a receiving space is provided in the pressure-maintaining shell (13), and an inlet hole and an outlet hole connected to the receiving space are also provided on the pressure-maintaining shell (13); the pressure-maintaining shell (13) is provided on the top surface of the valve base (1), and the inlet hole is connected to the small vent hole (5); the pressure-maintaining cover (12) is slidably connected to the receiving space and is used to open and close the inlet hole.

9. The combination valve according to claim 7, characterized in that: The sealing assembly (6) includes a sliding member (602) and a sealing member (601); the sliding member (602) is slidably connected to the valve core accommodating chamber (14), and the sealing member (601) is installed on the sliding member (602); the sealing member (601) is provided with a sealing block for sealing the large air vent (4), and is also provided with a connecting channel for connecting to the small air vent (5); the sliding member (602) is driven by the large valve core assembly to slide up and down, and cooperates with the sealing block to open and close the large air vent (4); the connecting channel connecting to the small air vent (5) is used to cooperate with the small valve core assembly to open and close the small air vent (5).

10. The combination valve according to claim 7, characterized in that: A plurality of vertically arranged first guide rails (1021) are provided on the inner wall surface of the adapter shell (102), and the large valve core assembly is slidably connected to the first guide rails (1021); a hollow part (1011) is provided on the bottom surface of the inner cavity of the outer shell (101), and the hollow part (1011) cooperates with the bottom surface of the inner cavity to form a vertical guide groove, and a plurality of vertically arranged second guide rails (1012) are provided on the inner wall surface of the hollow part (1011); the small valve core assembly is slidably connected to the second guide rails (1012).

11. The combination valve according to claim 7, characterized in that: The large valve core assembly includes a large float (7) and a large spring (8) for balancing the gravity of the large float (7). The large float (7) can move vertically up and down within the limited range of the valve core accommodating chamber (14), and when moving upward, it seals with the large vent hole (4) to close the large vent hole (4).

12. The combination valve according to claim 7, characterized in that: The small valve core assembly includes a small float (9) and a small spring (10) for balancing the gravity of the small float (9). The small float (9) can move vertically up and down within the limited range of the valve base (1) and the large float (7), and when moving upward, it seals with the small vent hole (5) to close the small vent hole (5).

13. The combination valve according to claim 7, characterized in that: The third inflow channel (19) is provided with a blocking member (21) for limiting the flow area of the inflow channel.

14. The combination valve according to claim 7, characterized in that: An upwardly concave groove is provided on the bottom surface of the housing (101), and the groove corresponds to the small valve core assembly and is used to raise the lowest sliding height of the small valve core assembly.

15. A CFLVV valve, characterized in that: The invention comprises a combination valve as described in any one of claims 7 to 14.

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