Electromagnetic valve for balancing the pressure in a tank

Abstract

The balanced oil tank pressure solenoid valve of the present application discloses a solenoid valve, which comprises an upper valve body, a middle valve body and a lower valve body, the inner cavity of the upper valve body is communicated with the inner cavity of the middle valve body, the communication part forms a sealing surface through a sealing assembly, the bottom end of the upper valve body is provided with a flange in contact with the sealing surface to form a first channel; the inner cavity of the middle valve body is communicated with the inner cavity of the lower valve body to form a cavity, a solenoid valve is fixed in the cavity, the solenoid valve is fixedly connected with the sealing assembly for driving the sealing assembly away from the upper valve body to open the first channel; the middle part of the sealing assembly is provided with a sealing guide rod, the sealing guide rod comprises a sealing joint, a guide rod and a small diameter spring, the bottom end of the sealing joint is provided with a flange in contact with the sealing surface to form a second channel, the guide rod is connected with the solenoid valve through a locking part after passing through a through hole, the locking part compresses the small diameter spring to make the second channel in a sealed state. The sealing mode is improved, and the overall sealing performance is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive fuel tank solenoid valve technology, specifically to a solenoid valve for balancing fuel tank pressure. Background Technology

[0002] During fuel consumption in a motor vehicle, the pressure inside the fuel tank can be lower than the external pressure. If this pressure difference exceeds a certain threshold, external gas needs to enter to maintain pressure balance. Conversely, if fuel evaporates under conditions such as high temperature and vibration, causing the internal pressure to exceed the external pressure, and this pressure difference exceeds a certain threshold, the fuel tank needs to be vented. The fuel tank isolation valve connects the high-pressure fuel tank and the carbon canister in a motor vehicle. One end connects to the exhaust system inside the fuel tank, and the other end connects to the carbon canister. Driven by an electrical signal, it facilitates pressure exchange with the atmosphere, balancing the pressure inside the fuel tank.

[0003] Existing tank isolation valves mainly consist of a valve body and a valve cover. A spring is fitted onto the valve, and an electromagnetic coil inside the valve body is energized. The electromagnetic force generated by the coil causes the moving iron core and the valve to move together, thereby opening and closing the valve. In this structure, the moving iron core is usually a solid structure, making the product relatively heavy. When installed horizontally, the weight of the iron core can cause significant tilting, affecting the product's sealing performance. The existing valve springs have a small outer diameter, resulting in weak support and stability for the moving iron core, further impacting sealing performance. Moreover, the moving iron core assembly is a one-piece metal structure, which is difficult and costly to manufacture, leading to significant material waste. The movement of the moving iron core in conjunction with the plastic frame is susceptible to changes in movement clearance due to high and low temperatures, potentially causing the moving iron core to jam. After millions of cycles of use, the plastic frame is prone to wear, making it difficult to guarantee the product's sealing performance. Furthermore, the existing valves use a sealing method where the rubber end is the line and the plastic part is the surface. The surface of the plastic part is easily deformed during injection molding, resulting in poor repeatability and reproducibility of the sealing performance. The existing irregular circular structure of valve cover mostly adopts circumferential welding, which is easily affected by injection molding deformation, leading to the risk of poor welding or missing welds. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing technologies by providing a solenoid valve for balancing the air pressure in an oil tank, improving the sealing method, and enhancing the overall sealing performance.

[0005] Technical solution: The solenoid valve for balancing the air pressure of the oil tank according to the present invention includes a valve body and a valve cover. The valve body includes an upper valve body, a middle valve body and a lower valve body. The upper valve body has a first vent pipe leading to the carbon canister and the middle valve body has a second vent pipe leading to the oil tank.

[0006] The upper valve body cavity is connected to the middle valve body cavity, and a sealing surface is formed at the connection point by a sealing assembly. The bottom end of the upper valve body is provided with a flange that contacts the sealing surface to form a first channel. A solenoid valve is fixed in the cavity formed by the connection between the middle valve body cavity and the lower valve body cavity. The solenoid valve is fixedly connected to the sealing assembly and is used to drive the sealing assembly away from the upper valve body to open the first channel. The first vent pipe is connected to the second vent pipe through the upper valve body cavity, the first channel, the middle valve body cavity, and the second vent pipe.

[0007] The sealing assembly has a through hole in the middle, and a sealing guide rod is provided at the through hole. The sealing guide rod includes a sealing joint, a guide rod perpendicularly connected to the sealing joint, and a small-diameter spring sleeved on the guide rod. The bottom end of the sealing joint has a flange that contacts the sealing surface to form a second channel. After the guide rod passes through the through hole, it is connected to the solenoid valve through a locking member. The locking member compresses the small-diameter spring to keep the second channel sealed. The solenoid valve has a valve chamber that is connected to the second vent pipe. When the pressure in the second vent pipe is greater than the pressure in the first vent pipe, the gas in the second vent pipe forces the small-diameter spring to stretch and open the second channel. The second vent pipe is connected to the first vent pipe through the valve chamber, the second channel, and the inner cavity of the upper valve body.

[0008] To further improve the above technical solution, the solenoid valve includes a fixed iron core, a coil assembly, and a moving iron core assembly. The fixed iron core is located at the bottom of the lower valve body, and the coil assembly is connected to the fixed iron core. The moving iron core assembly includes a moving iron core and a valve core. The moving iron core is a hollow cylinder with one end being a suction surface and the other end being an open end. The sealing assembly is sleeved on the sealing end of the valve core, and the other end of the valve core opposite to the sealing end is connected to the open end of the moving iron core.

[0009] Furthermore, the lower valve body is provided with a stainless steel sleeve along its inner wall, and a large-diameter spring is sleeved on the valve core. One end of the large-diameter spring is connected to the sealing end of the valve core, and the other end abuts against the stainless steel sleeve. The moving iron core is in sliding fit with the stainless steel sleeve.

[0010] Furthermore, the valve core is made of plastic.

[0011] Furthermore, the sealing assembly is made of rubber.

[0012] Furthermore, the contact parts of the upper valve body, the sealing joint, and the sealing assembly are made of plastic.

[0013] Furthermore, the valve core has a central cavity corresponding to the through hole of the sealing assembly, the guide rod passes through the central cavity of the valve core, and the locking member is fixed on the guide rod and limited by the bottom end of the valve core.

[0014] Furthermore, the small-diameter spring is positioned between the middle of the valve core and the locking element.

[0015] Furthermore, the valve cover is fitted over the upper valve body, and the fitting surface is sealed by end face welding.

[0016] Furthermore, the end face weld is formed using galvanometer scanning laser welding.

[0017] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows: The sealing structure designed in the present invention uses rubber as the contact surface for the sealing component, and plastic parts for the first channel and the second channel, forming a sealing method of rubber surface and plastic line, which is not easily affected by injection molding deformation, thereby ensuring the repeatability and reproducibility of sealing performance.

[0018] The moving iron core assembly forms a metal plus plastic structure, which reduces the difficulty and cost of processing and reduces material waste. The moving iron core is designed as a hollow structure, making the product lighter. When installed horizontally, the iron core tilts less due to gravity, thereby improving the product's sealing performance.

[0019] The large-diameter spring is compatible with the stainless steel sleeve. The larger outer diameter of the spring provides strong support and stability for the moving iron core, thus ensuring the product's sealing performance. The moving iron core and stainless steel sleeve move in tandem; the metal is unaffected by high or low temperatures, eliminating the risk of the moving iron core jamming, and allowing for even greater clearance. Using metal materials of comparable hardness minimizes wear, ensuring the product's sealing performance even after millions of cycles.

[0020] The valve cover and valve body are welded together by end face welding, which is not easily affected by injection molding deformation. End face welding can also effectively prevent incomplete welding. End face welding uses galvanometer scanning welding, which has higher welding efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is the front view of the present invention;

[0023] Figure 3 This is a cross-sectional view of the present invention;

[0024] Figure 4 yes Figure 3 Enlarged view of point C in the middle;

[0025] Figure 5 yes Figure 3 Enlarged view of point B in the middle;

[0026] Figure 6 This is a schematic diagram showing the top orientation of the moving iron core assembly;

[0027] Figure 7This is a schematic diagram showing the bottom orientation of the moving iron core assembly.

[0028] In the diagram: 1. Valve cover; 2. Valve body; 3. Valve core; 4. Sealing guide rod; 5. Large diameter spring; 6. Moving iron core; 7. Stainless steel sleeve; 8. Fixed iron core; 9. Coil assembly; 10. Sealing assembly; 11. First channel; 12. Second channel; 21. First vent pipe; 22. Second vent pipe. Detailed Implementation

[0029] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments described.

[0030] like Figure 1 , Figure 2 The solenoid valve for balancing the air pressure in the oil tank shown includes a valve body 2 and a valve cover 1. The valve body 2 includes an upper valve body, a middle valve body, and a lower valve body. The upper valve body has a first vent pipe 21 leading to the carbon canister, and the middle valve body has a second vent pipe 22 leading to the oil tank.

[0031] like Figure 3 As shown, the inner cavity of the upper valve body is connected to the inner cavity of the middle valve body. The connection is formed by the sealing component 10, which is made of rubber. The bottom end of the upper valve body has a flange that contacts the sealing surface to form the first channel 11. A solenoid valve is fixed in the cavity formed by the connection between the inner cavity of the middle valve body and the inner cavity of the lower valve body. The solenoid valve is fixedly connected to the sealing component 10 and is used to drive the sealing component 10 away from the upper valve body to open the first channel 11. The first vent pipe 21 is connected to the second vent pipe 22 through the inner cavity of the upper valve body, the first channel 11, and the inner cavity of the middle valve body.

[0032] The sealing assembly 10 has a through hole in the middle, and a sealing guide rod 4 is provided at the through hole. The sealing guide rod 4 includes a sealing joint, a guide rod perpendicularly connected to the sealing joint, and a small-diameter spring sleeved on the guide rod. The bottom end of the sealing joint has a flange that contacts the sealing surface to form a second channel 12. After the guide rod passes through the through hole, it is connected to the solenoid valve through a locking member. The locking member compresses the small-diameter spring to keep the second channel 12 in a sealed state. The solenoid valve has a valve chamber that is connected to the second vent pipe 22. When the pressure of the second vent pipe 22 is greater than the pressure of the first vent pipe 21, the gas in the second vent pipe 22 forces the small-diameter spring to stretch to open the second channel 12. The second vent pipe 22 is connected to the first vent pipe 21 through the valve chamber, the second channel 12, and the inner cavity of the upper valve body.

[0033] like Figure 4 As shown, the sealing structure designed in this invention uses rubber as the contact surface for the sealing component 10, and plastic parts for the first channel 11 and the second channel 12, forming a sealing method of rubber surface and plastic line, which is not easily affected by injection molding deformation, thereby ensuring the repeatability and reproducibility of sealing performance.

[0034] like Figure 5 The valve cover 1 shown is fitted onto the upper valve body, and the fitting surface is sealed with end face welding. The end face welding is formed by galvanometer scanning laser welding. The irregular circle of valve cover 1 is end face welded, which is not easily affected by injection molding deformation. End face welding can also effectively prevent weld leakage, and the end face welding using galvanometer scanning welding has higher efficiency.

[0035] like Figure 6 , Figure 7 As shown, the solenoid valve includes a fixed iron core 8, a coil assembly 9, and a moving iron core assembly. The fixed iron core 8 is located at the bottom of the lower valve body, and the coil assembly 9 is connected to the fixed iron core 8. The moving iron core assembly includes a moving iron core 6 and a valve core 3. The moving iron core 6 is a hollow cylinder with one end serving as a suction surface and the other end being open. A sealing assembly 10 is fitted onto the sealing end of the valve core 3, and the other end of the valve core 3 opposite to the sealing end is connected to the open end of the moving iron core. Designing the moving iron core 6 as a hollow structure makes the product lighter, and when installed horizontally, the tilt of the iron core is smaller due to gravity, thereby improving the sealing performance of the product. The valve core 3 is made of plastic, and the moving iron core assembly forms a metal-plastic structure, reducing processing difficulty and cost, and minimizing material waste.

[0036] A stainless steel sleeve 7 is provided along the inner wall of the lower valve body. A large-diameter spring 5 is fitted on the valve core 3. One end of the large-diameter spring 5 is connected to the sealing end of the valve core 3, and the other end abuts against the stainless steel sleeve 7. The moving iron core and the stainless steel sleeve 7 are in sliding fit. The valve core 3 has a central cavity corresponding to the through hole of the sealing assembly 10. The guide rod passes through the central cavity of the valve core 3, and the locking element is fixed on the guide rod and limited by the bottom end of the valve core 3. The small-diameter spring is limited between the middle of the valve core 3 and the locking element. The large-diameter spring 5 is adapted to the stainless steel sleeve 7. The outer diameter of the spring is large, which provides strong support for the moving iron core and thus ensures the sealing performance of the product. The moving iron core and the stainless steel sleeve 7 move together. The metal is not affected by high and low temperatures in terms of movement gap, and there is no risk of the moving iron core getting stuck. Moreover, the movement gap can be made higher. The use of metal materials with comparable hardness makes it less prone to wear, and the product can still guarantee its sealing performance after tens of millions of durability cycles.

[0037] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A solenoid valve for balancing fuel tank pressure, comprising a valve body and a valve cover, wherein the valve body includes an upper valve body, a middle valve body, and a lower valve body, the upper valve body having a first vent pipe leading to a carbon canister, and the middle valve body having a second vent pipe leading to the fuel tank; characterized in that: The upper valve body cavity is connected to the middle valve body cavity, and a sealing surface is formed at the connection point by a sealing assembly. The bottom end of the upper valve body is provided with a flange that contacts the sealing surface to form a first channel. A solenoid valve is fixed in the cavity formed by the connection between the middle valve body cavity and the lower valve body cavity. The solenoid valve is fixedly connected to the sealing assembly and is used to drive the sealing assembly away from the upper valve body to open the first channel. The first vent pipe is connected to the second vent pipe through the upper valve body cavity, the first channel, the middle valve body cavity, and the second vent pipe. The sealing assembly has a through hole in the middle, and a sealing guide rod is provided at the through hole. The sealing guide rod includes a sealing joint, a guide rod perpendicularly connected to the sealing joint, and a small-diameter spring sleeved on the guide rod. The bottom end of the sealing joint has a flange that contacts the sealing surface to form a second channel. After the guide rod passes through the through hole, it is connected to the solenoid valve through a locking member. The locking member compresses the small-diameter spring to keep the second channel sealed. The solenoid valve has a valve chamber that is connected to the second vent pipe. When the pressure in the second vent pipe is greater than the pressure in the first vent pipe, the gas in the second vent pipe forces the small-diameter spring to stretch and open the second channel. The second vent pipe is connected to the first vent pipe through the valve chamber, the second channel, and the inner cavity of the upper valve body.

2. The solenoid valve for balancing oil tank pressure according to claim 1, characterized in that: The solenoid valve includes a fixed iron core, a coil assembly, and a moving iron core assembly. The fixed iron core is located at the bottom of the lower valve body, and the coil assembly is connected to the fixed iron core. The moving iron core assembly includes a moving iron core and a valve core. The moving iron core is a hollow cylinder with one end being a suction surface and the other end being an open end. The sealing assembly is sleeved on the sealing end of the valve core, and the other end of the valve core opposite to the sealing end is connected to the open end of the moving iron core.

3. The solenoid valve for balancing oil tank pressure according to claim 2, characterized in that: The lower valve body is provided with a stainless steel sleeve along its inner wall, and a large-diameter spring is sleeved on the valve core. One end of the large-diameter spring is connected to the sealing end of the valve core, and the other end abuts against the stainless steel sleeve. The moving iron core is in sliding fit with the stainless steel sleeve.

4. The solenoid valve for balancing oil tank pressure according to claim 2, characterized in that: The valve core is made of plastic.

5. The solenoid valve for balancing the air pressure in the oil tank according to any one of claims 1 to 4, characterized in that: The sealing assembly is made of rubber.

6. The solenoid valve for balancing oil tank pressure according to claim 5, characterized in that: The contact parts between the upper valve body, the sealing joint, and the sealing assembly are made of plastic.

7. The solenoid valve for balancing oil tank pressure according to claim 2, characterized in that: The valve core has a central cavity corresponding to the through hole of the sealing assembly. The guide rod passes through the central cavity of the valve core, and the locking member is fixed on the guide rod and limited by the bottom end of the valve core.

8. The solenoid valve for balancing oil tank pressure according to claim 7, characterized in that: The small-diameter spring is positioned between the middle of the valve core and the locking element.

9. The solenoid valve for balancing oil tank pressure according to claim 1, characterized in that: The valve cover is placed on top of the upper valve body, and the covering surface is sealed by end face welding.

10. The solenoid valve for balancing the air pressure in the oil tank according to claim 9, characterized in that: The end face weld is formed by galvanometer scanning laser welding.

Images