JPH0590062U - Check valve - Google Patents

Abstract

(57) [Abstract] [Purpose] A check valve having a case mounted at the end of a flow path and a valve body that is fitted into an opening at one end of the case and closes the case. (EN) Provided is a check valve that reliably guides a valve element by a simple guide mechanism and positions it at a closed position even with a small configuration, and that prevents a back flow with high reliability. The inner peripheral surface (3) of the opening end edge of the case (1) is in sliding contact with the outer peripheral surface of the valve body (10) swinging inward so as to guide it to the closed position. ) Is a conical inclined surface (3) whose diameter decreases toward the inside.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention valve for preventing backflow in a refueling system of a fuel tank of an automobile, for example.

[0002]

[Prior Art]

 BACKGROUND ART Conventionally, as a backflow prevention valve for preventing a backflow in a refueling system of an automobile fuel tank, the one described in Japanese Utility Model Laid-Open No. 53-165928 is known. This is brought into contact with and separated from a valve element supporting element pivotally supported on the side surface of the fuel tank at one end and a valve seat section formed by an opening edge portion of the fuel inlet attached to the other end of the valve element supporting element. It consists of a valve body.

[0003]

[Problems to be solved by the device]

 The above-mentioned check valve is intended to prevent the problem that the fuel is blown out due to the internal pressure when the refueling port is opened, for example, but it has the following problems to be improved. That is, in the one disclosed in Japanese Utility Model Laid-Open No. 53-165928, the mechanism for guiding the valve body to the closed position (the position where the valve body properly contacts the valve seat portion without a gap) is a valve body supporting element. Since it is only the pivotal support part, it is necessary to use a pivotal support part (hinge part) having a certain axial length with little play. If this is not the case, the valve body may be able to move laterally, closing at a position displaced from the closed position, and in the worst case, the pipe opening may not be completely closed and backflow may occur. was there.

Therefore, in order to provide this kind of check valve, it is necessary to secure some space in the fuel tank on the side of the pipe end for arranging the pivot portion of the check valve. The degree of freedom in tank design is limited, and large and precise hinges, etc., are required to serve as pivots, resulting in high component costs or assembly costs. There was a problem that it was against the trend of cost reduction and cost reduction.

In order to solve the above problem, it is conceivable that the valve body has a diameter much larger than the opening area of the pipe so that a gap does not occur even if the valve body is slightly displaced and closed. , In this case, the basic function that the valve element may open due to the force of the fuel flow in the fuel tank on the part of the valve element that extends around the pipe, even if it is in the reverse flow state. About the problem arises.

The present invention has been made by paying attention to the problems of the prior art as described above. Even if the support element of the valve element has a simple and small structure, the simple guide mechanism ensures that the valve element can be securely attached. It is an object of the present invention to provide a check valve which is guided to and positioned in a closed position and which reliably prevents backflow.

[0007]

[Means for Solving the Problems]

 The gist of the present invention for achieving such an object is to provide an annular step (4) on the inner surface of one opening, and to prevent backflow with the opening outside. And a cylindrical case (1) attached to the case (1), which is swingably attached to the opening of the case (1), and when it swings to an inner closed position, its outer circumference becomes the step (4). A valve body (10) which is fitted into the case (1) to close the case (1), and a spring (20) which biases the valve body (10) inward, and the opening end of the case (1). The inner peripheral surface (3) of the rim swings inward, and the diameter is reduced toward the inner side of the case (1) so as to slide on the outer peripheral surface of the valve body (10) and guide it to the closed position. The check valve has a conical inclined surface (3).

[0008]

[Action]

 When a forward force is not applied to the valve body (10) by a fluid such as fuel, the valve body (10) is forcibly in the closed position by the urging force of the spring (20), but the flow with the case attached. When fuel or the like is fed into the passage and flows to the end of the passage, a large moment is generated in the valve body (10) by the force applied by the flowing fluid, and the valve body (10) instantly opens.

When the forward force applied to the valve body (10) disappears due to the fluid flow after refueling or the like, the valve body (10) returns to the closed position due to the biasing force of the spring (20) and the reverse pressure. However, at this time, even if the valve body (10) is slightly wobbled in the lateral direction, the valve body (10) is securely fitted into the stepped portion (4) of the case (1) and positioned at the closed position, Reliable and complete backflow of fluid is prevented. That is, even if the valve body (10) is oscillated toward the closed position in a state where the valve body (10) is slightly laterally displaced, the outer peripheral surface (12) of the valve body (10) and the inclined surface (3) of the case 1 are slid. By the contact, the valve body (10) is smoothly inserted and fitted, and the outer peripheral portion and the stepped portion (4) of the case (1) are brought into close contact with each other.

Then, when a pressure difference that causes backflow occurs thereafter, the stepped portion (4) of the case (1) and the outer peripheral portion of the valve body (10) which is further pressed against this stepped portion (4) by this pressure. Due to the close contact with, the higher the differential pressure (backflow pressure), the higher the sealing performance, and the case (10) is closed, and the backflow is completely prevented.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. As shown in the drawing, the check valve of the present embodiment is provided with a case 1 which is inserted and attached to an end portion of a pipe line 30 or the like for preventing a backflow, and a case 1 which is swingable in an opening portion outside the case 1. And a spring 20 for biasing the valve body 10 toward the closed side.

The case 1 has a cylindrical shape as a whole in which the peripheral edge of the outer opening is expanded in a brim shape, and a hook-shaped shaft support portion 2 is formed at one end of the outer opening to form the outer opening. An annular step portion 4 into which the valve body 10 in the closed position is fitted is formed on the inner surface of the portion. Then, the inner peripheral surface of the outer edge of the opening (in this case, coincides with the inner peripheral surface of the step portion 4) is designed so as to guide the valve body 10 when it swings inward. The conical inclined surface 3 has a diameter that decreases toward the inside. A protrusion 5 is formed at one location on the outer periphery of the case 1, and a U-shaped slit 6 is formed around the protrusion 5 so that the portion where the protrusion 5 is formed is flexible. Are formed.

In this case, the bottom surface of the step portion 4 (a surface perpendicular to the axis of the case 1) constitutes a valve seat surface with which the inner surface 13 of the valve body 10 in the closed position is in close contact. Is not limited to this mode, and the outer peripheral surface 12 of the valve body 10 is fitted in close contact with the inner peripheral surface (inclined surface 3) of the step portion 4 while leaving a gap between the valve body 10 and this bottom surface. A mode (that is, a mode in which the inclined surface 3 serves as a valve seat surface) may be used. The shaft support portion 2 supports the valve body 10 by locking a shaft portion 11 of the valve body 10 which will be described later. However, the shaft support portion 2 is small in size so that the valve body 10 may wobble sideways. You can use loose ones. That is, the shaft support portion 2 may be small enough to fit within the outer diameter of the case 1, and the inner diameter thereof has a margin with respect to the outer diameter of the shaft portion 11 so that the shaft portion 11 can be easily engaged and disengaged. It may be set to the value you have.

The valve body 10 has two arm portions 15 and 16 extending from one end of a disc-shaped main body portion, and a shaft portion 11 extending linearly between the arm portions and both sides thereof. It is something that can be done. The valve body 10 is rotatably supported by the case 1 by having the central portion of its shaft portion 11 engageably and disengageably fitted into the shaft support portion 2. Further, the outer peripheral surface 13 of the valve body 10 is a conical inclined surface that is in sliding contact with the inclined surface 3 of the case 1 when the valve body 10 swings inward. The diameter is set to be slightly smaller than that of the inclined surface 3 of the case 1, and the inner surface 13 of the valve body 10 is in close contact with the bottom surface of the stepped portion 4 of the case 1 as described above.

The spring 20 is formed by bending a wire material having elasticity such as metal, and has a U-shaped portion 23 formed between the two coil portions 21 and 22. In this spring 20, the coil parts 21 and 22 are fitted on both sides of the shaft part 11, respectively, and the U-shaped part 23 elastically abuts on the spring receiver 14 formed on the outer surface of the valve body 10, and By attaching 23 and 24 to the recesses 7 and 8 on both sides of the shaft support portion 2 of the case 1 in elastic contact with each other, a restoring force for urging the valve body 10 is generated. There is. The case 1 and the valve body 10 are, for example, molded products of synthetic resin.

Next, the operation will be described. As shown in FIG. 5, the above-described check valve has a hole 30 (or a recess) with which the projection 5 engages, which is formed at the end of the pipe 30 for preventing the back flow. It can be easily installed just by inserting it.

When a forward force is not applied to the valve body 10 by a fluid such as fuel, the valve body 10 is forcibly in the closed position by the urging force of the spring 20, as shown in FIG. When fuel or the like is sent into the pipe 30 and flows into this end of the pipe 30, the center of rotation (shaft 11) of the valve body 10 is located at the end, so the force exerted by the flowing fluid causes A large moment is generated in the valve body 10, the valve body 10 instantly opens, and greatly opens as shown in FIG.

When the forward force applied to the valve body 10 due to the fluid flow after the refueling is completed and the fluid flows out, the valve body 10 returns to the closed position due to the biasing force of the spring 20 and the backflow pressure. At this time, even if the valve body 10 is slightly wobbled in the lateral direction, the valve body 10 is securely fitted into the stepped portion 4 of the case 1 and positioned at the closed position, and the reverse flow of the fluid is reliably and completely prevented. That is, even if the valve body 10 is slightly laterally displaced and sways toward the closed position, the sliding contact between the outer peripheral surface 12 of the valve body 10 and the inclined surface 3 of the case 1 causes the valve body 10 to smoothly move. It is guided and fitted, and the inner surface 13 and the bottom surface of the stepped portion 4 of the case 1 are brought into close contact with each other. Then, when a pressure difference that causes backflow occurs thereafter, the differential pressure (backflow pressure) is generated due to the plane contact between the bottom surface of the step portion 4 and the inner surface 13 of the valve body 10 which is further pressed by this pressure. The larger the size, the higher the sealing performance, and the inside of the case 10 is closed, and the backflow is completely prevented.

Further, in this closed state, the valve body 10 is in a state of being fitted in the step portion 4 of the case 1, so that the valve body 10 is inserted by the flow of the fluid inside the fuel tank or the like into which the pipe 30 is inserted. It is also extremely unlikely that 10 will be struck from the side and open.

Therefore, according to the check valve of the above embodiment, the structure for rotatably supporting the valve body is extremely simple and small, but the check valve can be surely and completely prevented from being backflowed. It is possible to secure the degree of freedom in design when installing this type of check valve while maintaining the reliability of check valve prevention, or to reduce costs.

That is, with the above-mentioned check valve, first, the operational reliability of the check valve is improved. Also, since there is almost no portion that extends beyond the outer diameter of the pipe 30 (in particular, the rotation support portion of the valve body 10), the space around the position where this check valve is installed in the fuel tank etc. It can be used for equipment placement, etc., and the degree of freedom in design is improved. Further, since it can be configured by an integrally molded product including the rotation supporting portion of the valve body, the material cost can be reduced. Furthermore, since the valve body 10 and the spring 20 can be assembled by simply fitting them into the case 1 and can be mounted by simply fitting them into the pipe 30, there are various effects such as reduction in assembly cost and mounting cost.

In the above embodiment, the inclined surface of the case of the present invention and the inner peripheral surface of the stepped portion of the case into which the valve body is fitted are aligned with each other. As shown by the chain line, the opening end 1a of the case 1 is configured to extend outside the closed valve body 10, and the inner peripheral surface 3a of the opening end 1a including the inner peripheral surface 3 of the step portion of the present invention. A mode in which an inclined surface as a guide mechanism is configured may be used.

[0023]

[Effect of the device]

 According to the check valve according to the present invention, even if there is some rattling in the rotational support of the valve body, the valve body is guided by the inclined surface of the case and securely fits into the one end opening of the case. Since the valve is closed, the structure for rotatably supporting the valve body is simple and small, but the reverse flow is reliably and completely prevented. For this reason, it is possible to secure the degree of freedom in designing when providing this kind of check valve, and to reduce the cost, while maintaining the reliability of check valve that could not be achieved in the past.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a front view showing an embodiment of the present invention.

FIG. 3 is a side view showing an embodiment of the present invention.

FIG. 4 is a plan view showing an embodiment of the present invention.

FIG. 5 is a side sectional view showing the operation of the embodiment of the present invention.

[Explanation of symbols]

 1 ... Case 3 ... Slope 4 ... Step 10 ... Valve 11 ... Spring

Claims (1)

[Scope of utility model registration request] 1. A cylindrical case having an annular step formed on the inner surface of one opening, the cylindrical case being attached to the end of the flow path for preventing backflow with the opening outside, and the opening of the case. A valve body that is swingably attached to the member, and that, when swinging to an inner closed position, fits the outer periphery of the valve body to close the case, and a spring that biases the valve body inward. The inner peripheral surface of the opening end edge of the case contracts toward the inner side of the case so that the inner peripheral surface of the valve body slides in contact with the outer peripheral surface of the valve body and guides it to the closed position. A check valve with a conical inclined surface with a diameter.