JP3386984B2 - Fuel spill prevention valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on a fuel tank of a vehicle, particularly an automobile, and by communicating the inside of the fuel tank with the atmosphere at normal times, the fuel vapor is allowed to escape to the outside of the fuel tank so that the pressure inside the fuel tank can be controlled. The present invention relates to a fuel outflow prevention valve that prevents rising and prevents fuel from flowing out of a fuel tank when a vehicle falls, suddenly accelerates, or suddenly turns a steering wheel.

[0002]

2. Description of the Related Art The above-mentioned conventional fuel outflow prevention valve is made of polyacetal resin which is excellent in gasoline resistance and is not affected by gasoline contained in a fuel tank. It is attached. When the fuel tank is molded with resin, a high-density polyethylene resin suitable for blow molding, inexpensive, and excellent in gasoline resistance is used because it is molded by blow molding.

Therefore, when a fuel outflow prevention valve is attached to a metal fuel tank , for example, Japanese Utility Model Laid-Open No. 2-12051.
As described in, into the fuel tank, Ru mounting a fuel outflow preventing valve before assembling the fuel tank. Also,
When installing the fuel outflow preventing valve to the fuel tank made of high density polyethylene resin blow molded fuel tank is integrally molded, since it is difficult to assemble the fuel outflow preventing valve in advance the fuel tank, for example JitsuHiraku Sho 62-9
As described in JP 1721, a fuel outflow valve, screwed through the sealing material.

[0004]

However, when the fuel tank is molded of high density polyethylene resin and the fuel outflow prevention valve is screwed to the fuel tank as described above, the number of parts for mounting the fuel outflow prevention valve and There is an inconvenience that the number of assembling steps increases and the seal between the two becomes incomplete. Therefore, it is conceivable to weld the fuel outflow prevention valve to the fuel tank to ensure the sealability, but since the fuel tank and the fuel outflow prevention valve are made of different materials, it is difficult to weld them due to the difference in melting point between the two. There is an inconvenience.

The present invention has been made in order to solve the above-mentioned inconvenience, and provides a fuel outflow prevention valve which can secure a sealing property and can be easily attached to a resin fuel tank by welding. Is.

[0006]

Means for Solving the Problems] This inventions is molded with resin, a valve cylinder top wall is provided on the upper side with a vent hole in its central portion, so as to be integral with the upper side of the valve cylinder Molded with resin, the valve cylinder is positioned inside the opening to seal the opening of the fuel tank made of resin, and the flange is secured to the fuel tank with sealing property, and is connected to the vent hole of the valve cylinder. A mounting portion having pores, a valve seat ring arranged at the lower end of the vent hole of the valve cylinder, a lower lid functioning as a filter attached to the valve cylinder so as to close the lower end, and this lower lid is mounted. And a float having a valve head at the upper end that is arranged in the valve cylinder so as to be movable in the vertical direction and that opens and closes the vent hole by contacting and separating from the valve seat ring, and the valve seat in cooperation with the buoyancy of the float. It is composed of a spring biasing the float so as to close the ring of vents A fuel outflow preventing valve is obtained by forming the attachment portion with a resin having a molded resin having substantially the same coefficient of thermal expansion of the fuel tank. And, the resin for molding the mounting part and a high density polyethylene resin is preferable.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a state in which a fuel outflow prevention valve according to an embodiment of the present invention is fixed to a fuel tank, and FIG. 2 is a perspective view of a partially cut valve cylinder. In FIG. 1 or FIG. 2, reference numeral 1 denotes a valve cylinder formed of polyacetal resin that is highly rigid and can be molded with high dimensional accuracy, and has a plurality of claws 2a that increase in thickness upward on the outer peripheral surface of the lower end portion, and a side surface. Cylindrical wall 2 provided with a plurality of ventilation holes 2b
And a stepped hole having an orbiting tapered surface 3aa that closes the upper side of the cylindrical wall 2 and expands downward as shown in FIG. 4 described later, and a flat surface 3ab that orbits below the tapered surface 3aa. Upper wall 3 with (vent) 3a provided at the center
And a connecting cylinder 4 located outside the upper surface wall 3 at the center of the upper surface wall 3 and provided with a vent hole 4a communicating with the stepped hole 3a at the center, and on a concentric circle centering on the connecting cylinder 4. Top wall
3 and a plurality of connecting legs 5 located outside of the connecting pipe 4 and the connecting pipe 4 and the connecting leg 5, and a ventilation hole 6a having a diameter slightly smaller than that of the cylindrical wall 2 and communicating with the ventilation hole 4a is provided at the center. It is composed of a disc 6 and In addition, in the disk 6,
Ribs 6b directed upward are provided around the periphery,
A plurality of holes 6c penetrating in the vertical direction is provided.

Reference numeral 11 denotes a mounting portion formed on the upper side of the valve cylinder 1 by insert molding using high density polyethylene resin,
A connecting tube 12 extending in the horizontal direction after the vent holes 12a communicating with the vent hole 6a of the disc 6 is raised, a fixing portion 13 for fixing the connection tube 12 to the valve tube 1, connected to the fixed portion 13 cylinder 12 a plurality of reinforcing walls 14 for standing the, and a flange 15 extending to the horizontal direction on the outer periphery of the fixed portion 13. Incidentally, the inner peripheral portion of the flange 15, annular groove 16 is provided which is open downwardly.

Reference numeral 21 denotes a valve seat ring welded to the tapered surface 3aa and the flat surface 3ab of the upper surface wall 3, and as shown in FIG. 4, an annular base portion 22 formed by polyacetal resin and welded, and this base portion. An unwelded tubular portion 23, which is located inside 22 and is provided with a valve hole 23a that expands downward .
When, is composed of a connecting portion 24 for connecting the base 22 and the cylindrical portion 23, it is then thinner by providing an annular groove 25 which is open upward direction to the connecting portion 24. Reference numeral 31 denotes a float accommodated in the valve cylinder 1, a valve head 32 formed of polyacetal resin, provided with a vent hole 31a penetrating in the vertical direction , and opening / closing the valve hole 23a of the valve seat ring 21. Is provided at the top.

Reference numeral 41 denotes a coil-shaped spring housed in the valve cylinder 1, which is a weak biasing force and imparts a biasing force for assisting the initial movement of the float 31 to float. 51 is the valve cylinder 1
Shows a lower lid having a filter function for covering the lower part of the cylindrical wall 52 formed of polyacetal resin and provided with locking holes 52a corresponding to the plurality of claws 2a of the cylindrical wall 2 in the radial direction.
And a plurality of holes 53a penetrating vertically is formed in the lower wall 53 eclipsed set. T indicates a fuel tank molded by blow molding using high-density polyethylene resin,
An opening h for attaching the fuel outflow prevention valve is provided at the top.

FIG. 3 is a sectional view showing the cavity of the mold before the mounting portion is molded. In FIG. 3, D represents a lower mold, and as shown in FIG. 4, the core pin Pd was fitted into the stepped hole 3a of the upper surface wall 3, the ventilation hole 4a of the connecting cylinder 4, and the ventilation hole 6a of the disk 6. It accommodates the valve cylinder 1. U represents an upper mold, and accommodates the core pin Pu whose upper end portion of the core pin Pd abuts on one end portion.

Reference numeral C denotes a cavity formed by the valve cylinder 1, the lower mold D and the upper mold U, which is a space for molding the mounting portion 11. In addition, the ventilation hole 12a of the connecting tube 12
Are formed by the connected core pins Pd and Pu.

FIG. 4 is an explanatory view showing the mounting state of the valve seat ring, and FIG. 5 is an explanatory view of the sealing property due to swelling when gasoline permeates between the valve cylinder and the mounting portion.

Next, the operation of the mounting portion will be described after the molding and assembly of the mounting portion are described in sequence. First, insert molding of the mounting portion will be described. Cavity C for mounting valve cylinder 1 molded from polyacetal resin in lower mold D, and insert-molding mounting portion 11 using high-density polyethylene resin in valve cylinder 1 and upper and lower molds U and D
Are formed as shown in FIG.

At this time, the core pin Pd having a diameter of 4 mm is inserted from the stepped hole 3a of the upper surface wall 3 into the connecting cylinder 4 and the ventilation holes 4a and 6a of the disk 6 so as to project onto the disk 6, and the connecting tube 12 is inserted. A core pin Pu having a diameter of 4 mm forming the pore 12a (horizontal portion) is inserted into the upper mold U, and the upper end of the core pin Pd and the tip end portion of the core pin Pu are brought into contact with each other and pressed in the arrow direction. Next, the molten high-density polyethylene resin is injected into the cavity C with a high injection pressure, so that the high-density polyethylene resin fills the connecting leg 5 and the disc 6 and fills the valve cylinder 1, so that the connecting cylinder 12,
The mounting portion 11 including the fixing portion 13, the reinforcing wall 14 and the flange 15 can be formed as shown in FIG. 1.

The fixed parts 13 located above and below the disk 6
Are firmly and integrally connected by a plurality of holes 6c formed in the disk 6. Then, by pulling out the core pins Pd and Pu and removing them from the mold, the stepped hole 3a and the ventilation holes 4a and 6a and the ventilation hole 12a communicate with each other.

Next, the mounting of the valve seat ring will be described. As shown in FIG. 4, the base portion 22 of the valve seat ring 21 is welded to the tapered surface 3aa and the flat surface 3ab of the upper wall 3,
For example, it is attached by welding by ultrasonic welding. At the time of this welding, since the connecting portion 24 is thinned by the annular groove 25, the stress of the base portion 22 due to the heat welding does not act on the valve hole 23a, and the roundness of the valve hole 23a can be maintained.

Next, the assembly will be described. First, the float 31 is inserted into the valve cylinder 1 to which the valve seat ring 21 is attached as described above so that the valve hole 23a can be opened and closed by the valve head 32, and the spring 41 is provided between the float 31 and the lower lid 51. Assemble by positioning and locking the claw 2a of the cylindrical wall 2 in the locking hole 52a of the cylindrical wall 52.

Next, the mounting of the fuel outflow prevention valve will be described. First, as shown in FIG. 1, the fixed portion 13 of the fuel outflow prevention valve assembled as described above is inserted into the opening h of the fuel tank T formed of high-density polyethylene resin and positioned on the outer periphery of the fixed portion 13. The flange 15 is located on the outer peripheral surface of the fuel tank T around the opening h. Then, attach the entire periphery of the flange 15 welded to the fuel tank T, for example, welded Netsu溶 wear.

At the time of this welding, since the annular groove 16 is provided so as to open downward in the inner peripheral portion of the flange 15, the extra high density polyethylene resin of the flange 15 and the fuel tank T is introduced into the annular groove 16. Flowing into the flange 15
Since it does not squeeze out to the outer peripheral portion, the finished state of welding is improved. Since the welded flange 15 and fuel tank T are both made of high-density polyethylene resin,
Even if there is a temperature change, it changes with the same expansion rate and contraction rate. Therefore, the sealing property between the flange 15 and the fuel tank T is maintained in a good state without changing due to the temperature change.

Next, the operation will be described. First, Fig. 1
In the normal state in which the fuel outflow prevention valve is attached to the fuel tank T, the float 31 descends by its own weight against the urging force of the spring 41, and the valve head 32 opens the valve hole 23a of the valve seat ring 21. It is open. Therefore, the gasoline vapor generated in the fuel tank T is not limited to the holes 53a and 31a, the clearance between the cylindrical wall 2 and the float 31, and the holes 23a and 4a.
It is discharged via a, 6a and 12a, and the rise in pressure in the fuel tank T can be prevented.

[0022] Then, or by sudden acceleration of the automobile, a large inertial force off the sudden steering is generated, the gasoline by the inertial force flows from the hole 53a into the valve cylinder 1, the float 31 is attempting to floating (raised) by the buoyancy However, since the specific gravity of the float 31 is larger than that of gasoline, the float 31 cannot float by itself, and is floated by being assisted by the weak biasing force of the spring 41. Therefore, the valve head 32 causes the valve hole 23a of the valve seat ring 21 to rise. Close. Therefore, the gasoline can be prevented from flowing out of the fuel tank T.

It should be noted that the vehicle returns to a normal state and the valve cylinder 1
When the gasoline inside returns to the fuel tank T from the hole 53a,
The float 31 compresses the spring 41 by its own weight and descends to open the valve hole 23a. When gasoline penetrates the valve hole 23a and reaches the gap between the disk 6 and the fixed portion 13, the dimensional change rate due to the swelling of gasoline is higher in the high-density polyethylene resin than in the polyacetal resin. Stress is generated in the direction of the arrow shown, and the sealing property between the disk 6 and the fixed portion 13 is improved.

In the above embodiment, the mounting portion 11
I explained with the example of molding with high density polyethylene resin,
It goes without saying that the same effect can be obtained by molding the mounting portion 11 with a resin or a material having substantially the same coefficient of thermal expansion as the high-density polyethylene resin for molding the fuel tank T. Moreover, although the fuel has been described as gasoline, it goes without saying that it may be light oil.

[0025]

As described above, according to the present invention, since the valve cylinder and the mounting portion are divided, the mounting portion is formed.
As a resin, it can be welded to the fuel tank and the temperature
Even if it changes, the sealability with the fuel tank is secured, so
Available resin can be selected. Therefore, the mounting part
Welded the flange of the fuel tank to the fuel tank while ensuring the sealability.
Even if the temperature changes depending on the condition, the sealability with the fuel tank is ensured.
Can be kept.

[0026] Then, since the molded mounting portion with a resin having a molded resin having substantially the same coefficient of thermal expansion of the fuel tank, the temperature in the state in which the flange of the mounting portion is welded to secure the sealing property in the fuel tank changes Even so, the flange changes with substantially the same coefficient of thermal expansion and coefficient of thermal contraction as the fuel tank. Therefore, it is possible to secure the sealing property and easily attach the fuel outflow prevention valve to the resin fuel tank by welding. Furthermore
The resin that molds the mounting part, and the resin that molds the fuel tank.
Since it is made of high density polyethylene resin, the sealing property is improved.
It is possible to reliably prevent the fuel from flowing out.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a fuel outflow prevention valve according to an embodiment of the present invention is fixed to a fuel tank.

FIG. 2 is a perspective view of a partially cut valve cylinder.

FIG. 3 is a cross-sectional view showing a cavity of a mold before molding a mounting portion.

FIG. 4 is an explanatory view showing a mounted state of a valve seat ring.

FIG. 5 is an explanatory diagram of sealing performance due to swelling when gasoline permeates between the valve cylinder and the mounting portion.

[Explanation of symbols]

1 Valve Cylinder 3 Upper Surface Wall 3a Stepped Hole 11 Mounting Part 12a Vent Hole 15 Flange 21 Valve Seat Ring 31 Float 41 Spring 51 Lower Lid T Fuel Tank h Opening

Claims (2)

(57) [Claims] 1. A valve cylinder formed of resin and having an upper surface wall having a vent hole in a central portion provided on an upper side, and a resin cylinder integrally formed on the upper side of the valve cylinder,
The valve cylinder was positioned inside the opening in a state where the opening of the resin fuel tank was sealed, and the flange was fixed to the fuel tank while ensuring the sealing property, and had a vent hole communicating with the vent hole. A mounting portion, a valve seat ring arranged at the lower end of the vent hole of the valve cylinder, a lower lid functioning as a filter mounted so as to close the lower end of the valve cylinder, and the lower lid attached to the valve seat ring. A float, which is disposed in the valve cylinder so as to be movable in the vertical direction, has a valve head provided at the upper end for opening and closing the vent hole by contacting with and separating from the valve seat ring, and the valve in cooperation with the buoyancy of the float. A fuel outflow prevention valve comprising a spring for urging the float so as to close the vent hole of the seat ring, and a thermal expansion coefficient which is substantially the same as that of the resin used to mold the fuel tank.
A fuel outflow prevention valve , characterized in that the mounting portion is molded with a resin . 2. The fuel outflow prevention valve according to claim 1 , wherein the resin is a high density polyethylene resin.