JPS60536Y2 - liquid tank venting device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a venting device that can be effectively used in a liquid tank, such as a fuel tank of a motorized portable working machine, in particular, where the liquid level in the tank fluctuates violently.

Conventionally, as this type of ventilation device, the Utility Model Publication No. 47-26736
The one described in the publication No. 1 is known.

This will be explained based on FIG.

In FIG. 1, 1 is a liquid tank provided with a liquid inlet 2, 3 is a valve body for inhaling outside air made of a flat flexible hollow tube provided with a ventilation hole 4, and the substrate of this valve body 3 is 5 is placed on the upper end of the liquid inlet portion 2 and is press-fixed airtightly by a tank cap 6.

One end opening 7 of the valve body 3 is connected to the inner surface of the substrate 5 and communicates with the outside through a vent hole 8 of the tank cap 6.

Further, a cylindrical portion 9 is provided at the other end of the valve body 3, and this cylindrical portion 9 is supported by a protrusion 10 provided on the inner surface of the base plate 5.

As a result, a bent portion 11 is formed in the middle portion of the valve body 3, and the opposing walls 12a and 12b of the valve body 3 can be easily brought into close contact with each other (closing the valve).

The valve body 3, the substrate 5, the cylindrical portion 9, and the protrusion 10 are integrally molded, and the air passage 21 of the valve body 3 is formed of a thin, knife-shaped core mold.

FIG. 2 is an enlarged cross-sectional view of the valve body 3, showing opposing walls 12a,
12b shows the valve closed state in close contact.

In this state, gaps 14a and 14b are formed on both sides of the opposing walls 12a and 12b over the entire length of the valve body 3, but these gaps are formed by forming the air passage 21 (Fig. 1) with a core mold. In some cases, this occurs naturally in order to perform the molding smoothly.

When the inside of the liquid tank 1 shown in FIG. 1 becomes negative pressure, the valve body 3
As shown in the figure, the upper and lower opposing walls 12a and 12b are separated, and the valve is in an open state.

In the above configuration, when the liquid tank 1 shown in FIG. 1 shakes violently and the tank internal pressure rises, the opposing walls 12a and 12b of the valve body 3 come into close contact with each other due to the internal pressure, and the vent hole 4 of the valve body 3
is isolated from the outside air, and the liquid in the tank is prevented from spewing out.

On the other hand, when the tank internal pressure becomes negative pressure due to the use of the liquid in the liquid tank 1, the outside air flows through the ventilation path inside the valve body 3.
1 and a vent hole 4 to communicate with the inside of the tank, and the inside of the tank is maintained at atmospheric pressure.

On the other hand, the cylindrical portion 9 of the valve body 3 is simply engaged with the protrusion 10 of the base plate 5, and there is no liquid tightness between them.

Note that the vent hole 4 of the valve body 3 is not limited to the position shown in FIG. 1, but may be provided on the tip side (left side) of the valve body from the bent portion 11, or in the bent portion 11.

By the way, in the aeration device having the above-mentioned configuration, the valve body 3 does not have a sufficient shutoff action when the internal pressure of the tank increases, and a problem often occurs in which the liquid in the tank spouts out to the outside.

As a result of the inventors' investigation, the cause was found to be as follows.

That is, as shown in FIG.
Even if the valves 2b are in close contact with each other and the valve is in the closed state, there are gaps 14a and 14b on both sides, so the liquid in the tank may leak between the cylindrical part 9 (Fig. 1) and the protrusion 10 (Fig. 1), which are not liquid-tight. From there, the liquid flows out of the tank cap 6 through the gaps 14a and 14b.

The above problem can be solved by eliminating the gaps 14a and 14b, but this requires a core mold with sharp edges on both sides, and when the core mold is removed, the edges 3ay3b of the valve body 3 There is a drawback that the valve body 3 cannot be formed smoothly due to the edges being cut or bent.

This idea was made in view of the above problems, and provides a venting device for a liquid tank that allows smooth molding of the valve body and reliably prevents the liquid in the tank from gushing out to the outside when the valve is closed. The purpose is to

Embodiments of this invention will be described below with reference to the drawings.

FIG. 4 is a partial sectional view of a liquid tank venting device according to an embodiment of the invention, that is, an improved view of the cylindrical portion 9 of the valve body 3 and the protrusion 10 of the base plate 5 shown in FIG. Since the dimensions of the cylindrical portion 9 and the protrusion 10 are the same as those of the prior art, their illustration and description will be omitted.

In FIG. 4, the cylindrical portion 9 has an inward flange 15 at its outer end.
An annular crimp piece 16 is provided on the inner periphery of the inward flange portion 15.
is formed.

The protrusion 10 is composed of a circular base 17 and an outward flange 18 on the outer periphery of its lower end, and an annular crimping piece 19 is formed on the outer periphery of the outward flange 18 .

Further, as shown in FIG. 5, substantially circular i122 at 22 b are positively formed on both inner sides of the opposing walls 12a and 12b of the valve body 3 over the entire length of the valve body 3.

As shown in FIG. 6, this valve body 3 has upper and lower opposing walls 1
2a and 12b are separated and the valves are in an open state.

In the above configuration, when the cylindrical portion 9 shown in FIG. The annular crimping pieces 19 of the protrusion 10 are fluid-tightly crimped to the inner peripheral surface of the cylindrical portion 9, and the inward flange portion 15 is engaged with the outer flange portion 18, so that the cylindrical portion 9 can be removed from the protrusion 10 as follows: Prevented.

In the configuration shown in FIG. 4, the cylindrical portion 9 and the protrusion 10 are connected in a fluid-tight manner, so that the opposing walls 12a and 12b of the valve body 3 are closed tightly together, as shown in FIG. Even if the grooves 22a, 22b are present on both sides in the valve state, these grooves 22a, 22b are blocked from inside the tank, so the grooves 22a, 22b cannot be opened from between the cylindrical part 9 and the protrusion 10. The liquid inside the tank will not flow out through the tank cap 6 to the outside.

In addition, since the semi-circular grooves 22a and 22b are positively formed, both sides of the core mold for forming the air passage 21 have round edges, which prevents the valve body from being damaged by the core mold. Curving at the edges of the core mold itself is prevented and molding becomes smooth.

As explained above, according to this invention, it is possible to reliably prevent the liquid in the tank from gushing out to the outside when the valve body is closed, and it is also possible to smoothly mold the device.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a conventional liquid tank aeration device;
Fig. 2 is an enlarged sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a sectional view showing the valve body in its open state, and Fig. 4 is a portion showing the venting device for a liquid tank according to this invention. 5 is a sectional view corresponding to FIG. 2 showing the valve body of the device, and FIG. 6 is a sectional view showing the valve body in an open state. 2...Liquid inlet part, 3...Valve body, 5
...Substrate, 9...Cylindrical part, 10...
... Protrusion, 12a, 12b ... Opposite wall, 2
2a, 22b...grooves.

Claims (1)

[Scope of utility model registration request] A substrate attached to the liquid inlet, an outside air intake valve body consisting of a flat flexible hollow tube whose one end is integrally connected to the inner surface of the substrate and whose other end is a cylindrical portion, and the inner surface of the substrate. In the aeration device for a liquid tank, the cylindrical portion of the valve body is connected to the base plate, and the cylindrical portion of the valve body is connected to the substrate. A liquid tank characterized in that the protrusion is crimped and locked in a liquid-tight manner on the outer periphery of the protrusion, and grooves having a substantially circular cross section and extending over the entire length of the valve body are formed on both inner sides of opposing walls of the valve body. Ventilation device.