| Fuel sealing structure -> Monitor Keywords |
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Fuel sealing structureRelated Patent Categories: Receptacles, Closures, Removable Closure Guided In Rotary Movement (e.g., Screw), With Packing Or GasketFuel sealing structure description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070181580, Fuel sealing structure. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] This invention relates to a fuel sealing structure. BACKGROUND ART [0002] It is known to interpose an annular packing between an opening part of a container such as a fuel tank and a closure in order to prevent the leakage. FIG. 10 of Japanese Patent Application Laid-Open No. 2002-337916 discloses a packing having a uniform thickness. This packing is interposed between an annular sealing surface on an opening part of a container and an annular sealing surface of a closure. The two sealing surfaces are planar surfaces (planes) which are parallel to each other. At the time of attaching the closure, the packing is uniformly compressed by the two sealing surfaces. The two surfaces of the compressed packing are adhered to the seating surface on the container and the sealing surface on the closure with a predetermined pressure, respectively, thereby preventing the leakage of fuel. DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention [0003] In the fuel sealing structure of the Japanese Patent Application Laid-Open No. 2002-337916, in case the packing is thick, the amount of the gasified fuel permeated through the rubber material of the packing is increased. In order to restrain the amount of permeating fuel, it is necessary to reduce the permeating sectional area by making the packing thinner. In case the packing is made thinner, however, there arises another inconvenience. This inconvenience will be described with reference to FIG. 7. [0004] FIG. 7 shows the changes of compression ratio of the packing in accordance with movement of the closure in the axial direction. In FIG. 7, the axial movement of the closure from the time the attachment of the closure is started until the time the compression of the packing is started is omitted. In other words, the amount of movement of the closure is set to zero at the time of starting of the compression. As the closure is moved in the axial direction, the compression ratio of the packing is increased. This change, in case the packing is thin, is great compared with the packing that is thick. [0005] At the time the closure is pushed in for a predetermined amount, the attachment of the closure is completed. There can be found some error in amount of axial movement of the closure until the closure reaches the attachment completing position. As mentioned above, in case the packing is thin, the change of compression ratio of the packing is large per unit of movement of the closure. Accordingly, the error of compression ratio becomes large corresponding to the error of the amount of axial movement of the closure, and there is a possibility that the error of compression ratio is out of the allowable range of error. When the actual compression ratio of the packing exceeds the upper limit of the allowable range of error, breakage of the packing occurs, and when the ratio becomes lower than the lower limit of the allowable range of error, the adhering force between the packing and sealing surfaces of the container and closure is lowered and thus, the sealability of the liquid fuel is lowered. Means for Solving the Problem [0006] To solve the above problem, the present invention provides a fuel sealing structure comprising a container for storing fuel and having an opening part, a closure attached to the opening part of the container, and an annular packing interposed in a compressed condition between an annular sealing surface of the container and an annular sealing surface of the closure, wherein the sealing surfaces of the container and closure each include an annular first region and an annular second region disposed radially inside or outside of the first region, and a distance between the second regions of the two sealing surfaces is shorter than that between the first regions, the packing includes a first sealing part sandwiched between the first regions of the two sealing surfaces and a second sealing part sandwiched between the second regions of the two sealing surfaces, the first and second sealing parts are, in their compressed condition, interposed between the sealing surfaces, the second sealing part is smaller in thickness than the first sealing part in a natural condition, and this difference in thickness is larger than the difference between the distance between the first regions and the distance between the second regions. [0007] Owing to the above construction, in the first sealing part, the change of compression ratio with respect to the amount of axial movement of the closure is gentle, the compression ratio can be managed with a comparatively high precision, and the change of compression ratio can be set within an allowable range. As a result, the packing can be adhered to the sealing surface of the container and the sealing surface of the closure with a sufficient pressure without the occurrence of breakage of the packing, and the leakage of liquid fuel can reliably be prevented. In the second sealing part, since the packing is smaller in thickness than in the first sealing part and the permeating sectional area is small, the permeation of the gasified fuel can be restrained. Moreover, since the difference of thickness between the first and second sealing parts is larger than the difference between the distance between the first regions and the distance between the second regions, the amount of compression of the second sealing part is smaller than that of the first sealing part, the overly compression of the second sealing part can be avoided, and the breakage of the packing at its second sealing part can be prevented. [0008] Preferably, a compression ratio of the second sealing part is smaller than that of the first sealing part when the closure is in an attached condition. Owing to this arrangement, even if some error occurs at the attaching position of the closure, the overly compression of the second sealing part can reliably be prevented. [0009] Preferably, the first sealing part is located radially inside of the second sealing part. Owing to this arrangement, the liquid fuel is prohibited in the first sealing part and does not reach the second sealing part. Thus, the second sealing part can limit its task only to prevention of permeation of a small amount of gasified fuel, the amount of compression can be reduced extensively, and breakage of the packing at the second sealing part can more reliably be prevented. [0010] In one embodiment, one of the sealing surfaces of the container and closure is a plane with the first and second regions made flush with each other, and the other sealing surface includes a step at a boundary between the first and second regions, one surface of the packing is a plane corresponding to the one sealing surface, and the other surface includes a step corresponding to the other sealing surface. Owing to this arrangement, the effect of the present invention can be obtained with a comparatively simple packing structure and sealing surface configuration. [0011] In another embodiment, an annular projection is formed on one of the sealing surface of the container and the sealing surface of the closure, a top surface of the projection is provided as the second region, a radial inside and a radial outside of the projection in the one sealing surface are provided as the first regions, the other sealing surface includes the second region and the first regions disposed radially inside and outside of the second region on a same plane in correspondence to one sealing surface, and the packing includes the thin second sealing part corresponding to the projection and the thick first sealing parts located radially inside and outside of the second sealing part. Owing to this arrangement, two sealing parts are employed and thus, liquid tightness can be enhanced. [0012] According to another aspect of the present invention, there is provided a fuel sealing structure comprising a container for storing fuel and having an opening part, a closure attached to the opening part of the container, and an annular packing interposed in a compressed condition between an annular sealing surface of the container and an annular sealing surface of the closure, wherein an annular elastically deformable permeation restraining plate having a lower fuel permeability than material of the packing is embedded in the packing, the permeation restraining plate extends radially of the packing, a distance between the permeation restraining plate and one surface of the packing is shorter than that between the permeation restraining plate and the other surface of the packing at a certain annular part but a distance between the permeation restraining plate and the other surface of the packing is shorter than that between the permeation restraining plate and the one surface of the packing at other annular part. [0013] Owing to the above construction, the gasified fuel is divided into two groups and permeates the packing material through one and the other sides of the permeation restraining plate. The first group of gasified fuel passing through one side of the permeation restraining plate is restrained in permeation at a place having a small permeating sectional area between a certain annular part of the permeation restraining plate and one surface of the packing, and the second group of gasified fuel passing through the other side of the permeation restraining plate is restrained in permeation at a place having a small permeating sectional area between the other annular part of the permeation restraining plate and the other surface of the packing. As a result, the total amount of the permeating gasified fuel can be restrained. Moreover, the packing is not required to be made thin in order to restrain the permeation of gasified fuel and the change of compression ratio can be made gentle with respect to the amount of axial movement of the closure. Thus, the compression ratio can be managed with a comparatively high precision and set within an allowable range. As a result, the packing can be adhered to the sealing surface of the container and the sealing surface of the closure with a sufficient pressure without the occurrence of breakage of the packing, and the leakage of liquid fuel can reliably be prevented. [0014] Preferably, both surfaces of the packing are planes and have a uniform thickness, and the permeation restraining plate is inclined at a surface connecting the certain annular part and the other annular part together. Owing to this arrangement, the packing can be made simple in structure. Effect of the Invention [0015] According to the present invention, a liquid fuel can satisfactorily be sealed. Also, a gasified fuel can satisfactorily be restrained in permeation. Moreover, breakage of the packing can be avoided. BRIEF DESCRIPTION OF DRAWINGS [0016] FIG. 1 is a vertical sectional view of a fuel sealing structure according to a first embodiment of the present invention. [0017] FIG. 2 is an enlarged vertical sectional view of the sealing structure, showing a state of a packing immediately before its first sealing part is compressed. Continue reading about Fuel sealing structure... Full patent description for Fuel sealing structure Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Fuel sealing structure patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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