JPH0540368Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] This invention relates to improvement of check valves.

[Prior Art] As is well known, a cap attached to a fuel filler port of a fuel tank is used to prevent the internal pressure of the fuel tank from rising excessively beyond a predetermined value, and to prevent the internal pressure of the fuel tank from rising excessively. A check valve is provided to prevent the pressure from dropping excessively below atmospheric pressure and creating a vacuum.

Since the check valve is housed within the cap of the fuel tank, it is required to be small and simple in structure.

[Problems to be solved by the invention] However, conventionally, in the space inside the casing of a check valve, not only a valve body and a spring member that biases the valve body, but also a valve seat and the valve seat are attached to the casing. A problem arises in that a fixing member for fixing the check valve is housed, making the internal structure of the check valve complicated.

[Purpose of the invention] This invention was made in view of the above problems, and the purpose is to provide a check valve whose internal structure is simplified by using a part of the casing as the valve seat. do.

[Means for solving the problem] Therefore, this invention has at least one
It is defined by an upper casing having three or more communicating holes, a lower casing having a recess with a hole in the center and fixed in the upper casing, and an upper surface of the lower casing and the upper casing. A sealing member is housed in the space and is formed in a concave shape using a highly elastic material, has a sealing part protruding downward at the bottom of its outer periphery, has a hole in the center of the bottom part, and a sealing member near the outer periphery. a spring receiver having at least one or more holes therein and housed in the recess of the sealing member; and a spring compressed between the spring receiver and the upper surface of the upper casing; Until the pressure below the lower casing reaches a predetermined value, the seal part of the sealing member is pressed against the bottom surface of the recess in the lower casing to cut off the lower part of the lower casing and the upper part of the upper casing, and the lower part of the lower casing is When the downward pressure exceeds the predetermined value, the seal part of the seal member is set to move away from the bottom of the recess in the lower casing, and when negative pressure is generated below the lower casing, the bottom part of the seal member is elastically bent. The lower part of the lower casing and the upper part of the upper casing are made to communicate with each other.

[Effect of the invention] According to this invention, the lower casing serves as a valve seat for the sealing portion of the sealing member that blocks the lower part of the lower casing from the upper part of the upper casing until the pressure below the lower casing reaches a predetermined value. In addition, when a negative pressure is generated below the lower casing, the bottom surface of the sealing member is elastically bent to establish communication between the lower part of the lower casing and the upper part of the upper casing. The valve seat and the fixing member for fixing the valve seat to the casing, which were conventionally provided separately, can be eliminated. As a result, the internal structure of the check valve can be significantly simplified.

[Example] Hereinafter, an example of this invention will be described based on the accompanying drawings.

As shown in FIG. 1, the upper casing 2 of the check valve 1 according to the first embodiment of this invention is formed by pressing a steel plate, and the lower surface of the upper casing 2 has a lower part made of a pressed steel plate. The casing 3 is fixed. The lower casing 3 has a recess in the center, and a seal member 5 made of a highly elastic material such as rubber is provided in a space 4 defined by the recess and the upper surface 2a of the upper casing 2. It is stored. The sealing member 5 is formed into a concave shape, and a spring receiver 6 is mounted within the concave portion. The seal member 5 is biased downward by a spring 7 compressed between the spring receiver 6 and the upper surface 2a of the upper casing, and is normally provided on the bottom surface of its outer periphery so as to protrude slightly downward. The seal portion 5a is pressed against the bottom surface 3a of the recessed portion of the lower casing 3.

The check valve 1 having the above configuration is installed in a cap (not shown) of a fuel tank (not shown) so that the lower side in the figure is on the fuel tank (not shown) side.

When the pressure inside the fuel tank (not shown) exceeds a predetermined value, the seal member 5 is lifted against the biasing force of the spring 7, and the seal portion 5a is separated from the recess bottom surface 3a. Therefore, in this case, the pressure inside the fuel tank (not shown) is
from the port 3b provided in the center of the seal part 5
The liquid is discharged to the outside through a plurality of communication holes 2b provided in the upper surface 2a of the upper casing through the gap and the space 4 formed between the bottom surface 3a and the bottom surface 3a of the upper casing.

On the other hand, until the pressure inside the fuel tank (not shown) reaches a predetermined value, the seal portion 5 of the seal member 5
a is the bottom surface 3 of the recess due to the biasing force of the spring 7.
Since it is pressed by a, the fuel tank (not shown)
Backflow of fuel from the inside to the outside is prevented.

In addition, when negative pressure is generated inside the fuel tank (not shown), the pressure difference between the outside and the inside of the fuel tank (not shown) causes the bottom surface of the sealing member 5 to
b elastically bends downward using the root of the seal portion 5a as a fulcrum, and a gap is formed between the lower surface of the spring receiver 6 and the bottom surface portion 5b. Therefore, in this case, external atmospheric pressure is transmitted to the spring receiver 6 through the communication hole 2b of the upper casing 2 and the space 4.
From a plurality of holes 6b provided near the outer periphery of
The fuel is introduced into a fuel tank (not shown) through a gap formed between the lower surface of the spring receiver 6 and the bottom surface 5b of the seal member 5 through a hole 5c provided in the center of the bottom surface 5b. .

As described above, according to the first embodiment of the present invention, in the check valve 1 installed in the cap (not shown) of a fuel tank (not shown), the inside of the fuel tank (not shown) The concave bottom surface 3a of the lower casing 3 is used as a valve seat for the seal portion 5a of the seal member 5 that shuts off the inside and outside of the fuel tank (not shown) until the pressure reaches a predetermined value. When negative pressure is generated inside the fuel tank (shown in the figure), the bottom surface 5b of the seal member 5 elastically bends to communicate between the inside and outside of the fuel tank, unlike conventionally provided separately. The valve seat and the fixing member for fixing the valve seat to the casing can be omitted. As a result, the internal structure of the check valve 1 can be significantly simplified.

FIG. 2 shows a second embodiment of the present invention, and according to this embodiment, the spring holder 16
is open upward and has a collar 16 at the upper end.
It is formed into a thin cylindrical shape with a. The spring 17 is located within the spring holder 16 and compressed between the bottom surface of the spring holder 16 and the top surface of the upper casing 12. The seal member 15 is attached to the collar portion 16 of the spring holder 16.
a and the outer surface of the cylindrical portion 16b, and are fitted so as to cover the flange portion 16a and the cylindrical portion 16b.
It is fixed to 6.

In this embodiment, a valve seat portion is formed in a stepped portion 13a of the lower casing 13 cut out by machining, and is adapted to be combined with the collar portion 15a of the seal member 15. Further, in a normal state where positive pressure is applied below the lower casing 13, the cylindrical portion 15b of the sealing member 15 covers and closes the plurality of communication holes 16c provided in the cylindrical portion of the spring holder 16, and closes the holes 16c. When negative pressure is applied below the flange 15a, the flange 15a elastically bends around the base thereof, opens the communication hole 16c, and introduces atmospheric pressure from the outside below the lower casing 13.

Further, in the first embodiment and the second embodiment, when negative pressure is generated below the lower casing, atmospheric pressure can be introduced from the outside into the fuel tank (not shown). In the example, because the distance between the bottom surface 5b of the seal member 5 and the bottom surface 3a of the recess of the lower casing 3 is narrow, in the second embodiment, the outer diameter portion of the cylindrical portion 15b of the seal member 15 and the port of the lower casing 13 are Due to the narrow distance between the inner diameter portion of 13b, it was not possible to secure a sufficient introduction path for atmospheric pressure. Below, when negative pressure occurs below the lower casing, a sufficient introduction path can be secured to introduce atmospheric pressure from the outside below the lower casing. An example will be described in which it is possible to suitably adapt to the conditions.

As shown in FIG. 3, in the third embodiment of the present invention, a spring holder 26 is formed into a cylindrical shape that opens upward and has a flange 26a at the upper end, and a spring 27 is inserted into the spring holder 26. positioned. The seal member 25 is formed in a shape that follows the outer shape of the spring holder 26, and has a hole 25c provided in the center of its bottom surface 25b.

In this embodiment, the stepped portion 23 of the lower casing 23
A valve seat portion is formed at b, and is adapted to be combined with the flange portion 25a of the seal member 25. In a normal state where positive pressure is applied below the lower casing 23, the plurality of holes 26b provided in the bottom surface of the spring holder 26 are closed by the bottom surface 25b of the seal member 25. On the other hand, when negative pressure is generated below the lower casing 23, the bottom surface portion 25b elastically bends downward using its root as a fulcrum, opening the hole portion 26b, and lowering the lower casing 23.
3 and the upper part of the upper casing (not shown) are communicated with each other. In this embodiment, since the valve seat portion is provided on the stepped portion 23b of the lower casing 23, the bottom surface portion 25b of the sealing member 25 and the lower casing 2
A sufficient gap can be provided between the hole 26b and the bottom surface 23a of the recess 3, and a sufficient flow path can be secured when the hole 26b is opened.

Further, the fourth embodiment of the present invention, as shown in FIG. 4, has almost the same structure as the second embodiment (see FIG. 2), but the lower casing 33 is made of pressed steel plate. By enlarging the diameter of the port 33b and enlarging the diameters of the collar 36a of the spring holder 36 and the collar 35a of the seal member 35, the outer diameter of the cylindrical portion 35b of the seal member 35 and the inner diameter of the lower casing 33 are the second interval
It is made sufficiently larger than in the embodiment to ensure a sufficient flow path when the communication hole 36c of the spring holder 36 opens.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a check valve according to a first embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of a check valve according to a second embodiment of the present invention, and FIG. 3 is a vertical cross-sectional view of a check valve according to a second embodiment of the present invention. FIG. 4 is a vertical cross-sectional view showing the main parts of a check valve according to the fourth embodiment of the present invention. 1...Check valve, 2...Upper casing, 2a...
...Top surface part of upper casing, 2b...Communication hole,
3, 13, 23, 33...lower casing, 3
a, 23a...Bottom surface of the recess of the lower casing, 3
b, 13b, 33b...port, 4...space part,
5, 15, 25, 35,...Seal member, 5a...
...Seal part, 5b, 25b...Bottom part, 5c, 2
5c... Hole, 6... Spring receiver, 16,2
6, 36...Spring holder, 7, 17, 27
……spring.

Claims (1)

[Claims for Utility Model Registration] An upper casing having at least one communication hole in its upper surface, a lower casing having a recess with a hole in the center and fixed within the upper casing, and the lower casing. It is housed in a space defined by the casing and the upper surface of the upper casing, and is formed in a concave shape from a highly elastic material. a seal member having a hole in the center; a spring receiver having at least one hole near the outer periphery and housed in the recess of the seal member; and the spring receiver and the upper surface of the upper casing. and a spring compressed between them, and the biasing force of the spring is applied to press the seal portion of the seal member against the bottom surface of the recess in the lower casing until the pressure below the lower casing reaches a predetermined value. The lower part is cut off from the upper part of the upper casing, and when the lower pressure of the lower casing exceeds the predetermined value, the seal part of the seal member is set to separate from the bottom of the recess of the lower casing, and a negative pressure is applied to the lower part of the lower casing. A check valve characterized in that when pressure is generated, a bottom portion of the sealing member elastically bends to establish communication between the lower part of the lower casing and the upper part of the upper casing.