Patent Application
20070062841
This invention relates to cover-mounting structures of a plastic container such as an automotive fuel tank, which container has an opening provided with a cover mounted to close the opening.
The plastic container provided with an opening at one surface and a cover for closing the opening is employed, for example, as an automotive fuel tank or the like. An example of the automotive fuel tank is schematically illustrated in perspective in
It has been known in the art to provide a plastic container to be used as a fuel tank which has a holding ring structure for fixing a cover over the opening of a tank body made of plastic. A structure is disclosed in EP 0 816 151 A1, in which a groove for receiving a seal is formed on a top surface of a flange portion around the opening of the plastic tank body, so that the plastic tank body and its cover are fastened together using a holding ring made of metal with the seal being held in the groove.
As shown in FIGS. 24(a) and 24(b), a holding ring 420 made of metal is fitted on a flange portion 412 defining an opening 414 of the fuel tank 410. The holding ring 420 is comprised of segmental rings 420a and 420b, which are hinged on hooks 422 and fastened together using a bolt 424 and a nut 425. These segmental rings 420a, 420b clamp a holding plate 416 as a cover of a fuel tank 410 to the flange portion 412, thereby hermetically closing the fuel tank 410.
Another structure is disclosed in JP 2002-187162 A in which on top of a plastic body of a tank is fitted an upper plate or the like made of metal through which filler tubes and the like are led out of the tank, and a camlock member made of metal that has been insert-molded in the plastic body of the tank is provided for fixing the upper plate.
A metal upper plate (not shown) or the like through which filler tubes (not shown) and the like are led out is fitted on top of a plastic tank body 501a that, as shown in
As shown in
In a conventional plastic fuel tank, a fuel pump having a portion to be inserted into the fuel tank is mounted on a mount plate, and fixed to the fuel tank. The fuel tank thus has an opening for fitting the mount plate therein, and the mount plate fitted in the opening has a sealing structure for liquid-tightly closing the fuel tank. To that end, a structure known in the art provides a threaded portion integrally formed at the opening of a plastic fuel tank and a plastic cap member to be screwed onto the threaded portion with a mount plate of the fuel pump held between the cap member and the plastic fuel tank, thereby fixing the fuel pump to the fuel tank. One example of this structure is disclosed in JP 2002-80054 A.
The part fixing portion has a sealing structure in which an annular seal 786 is fitted around the periphery of a reducer portion 788, which is provided at an edge of the cylindrical threaded portion 783 with a radial portion 787 lying therebetween, so that screwing the lock nut 784 on allows the seal 786 to be pinched between a seal surface 787a extending radially on an upper side of the radial portion 787 and a seal surface 785a formed opposite thereto on an under side of the cover plate 785, thereby exerting its sealing capability. Around the periphery of the seal 786 is provided a substantially vertically curved cylindrical surface 784a formed on the inner cylindrical surface of the lock nut 784 near the seal 786 as a restrictive means for restricting the expanded seal 786 from protruding in radially outward directions. The cylindrical surface 784a serves to restrict the outward protrusion of the seal 786. Therefore, the outward protrusion beyond a position at which the cylindrical surface 784a places a restriction on the seal 786 that is likely to expand as a result of absorption of fuel components. This makes the seal 786 kept from shifting away from the positions at which it is adhered to the seal surfaces 785a, 787a and from changing considerably in cross-sectional shape, thereby serving to prevent diminishment in sealing properties.
The applicant of the present application has filed Japanese Patent Application No. 2002-355459 entitled “Cover-Mounting Structure of Fuel Tank”.
In the field of art directed to cover-mounting structures of a plastic container such as an automotive fuel tank, it has been generally known to provide a mounting part for fixing a cover over an opening of a plastic container body, and a supporting part for fixing the mounting part. For example, a structure as shown in
As shown in
For a plastic container having the aforementioned cover-mounting structure, for example in a case where it is particularly used for an automotive fuel tank, a submergence leak test as shown in
If the fuel tank 940 has a leak, bubbles formed at a spot where the leak would occur rise and swell in the water; thus, visual observations, made from a direction indicated by arrow Y, of the bubbles show whether the fuel tank 940 has a leak at any spot.
Among the aforementioned conventional examples, however, the structure which is configured to have a holding ring divided into two segments which are in turn fastened together using a bolt/nut pair so as to clamp a cover disadvantageously could not exercise sufficient fastening strength.
In addition, such a divided holding ring could hardly form a perfect circle, and thus segmentally contact the outer surface of the wall defining the opening of the tank body, which would disadvantageously make its sealing performance insecure.
The structure which is configured to have a holding ring (camlock member) embedded in the external surface of the wall of the tank body made of plastic by an insert molding process would sever a barrier layer of the plastic tank body, which would undesirably affect a layer structure thereof.
Further, among the aforementioned conventional examples is a structure in which a surface for seal installation is provided near the opening of the tank body made of plastic, a groove is formed in the surface for seal installation, and a seal is placed in the groove. The problems encountered in this structure are: it would be difficult to ensure dimensional accuracy of the height of the upper surface on either side of the groove which height is measured when the upper surface comes into contact with the holding plate, and particularly to control the dimensional accuracy in a blow molding process; it would be difficult to finish a bottom surface of the groove to the highest standard in surface roughness, with the result that good sealing performance could not be achieved.
On the other hand, the structure in which the fuel tank is made of plastic, and a tank body thereof and a cover plate (mount plate) as a cap member are made of plastic would undergo deterioration effects of time on plastic material, disadvantageously lowering the accuracy and strength of a portion where the part fixing portion is mounted.
Since still another of the aforementioned conventional examples in which the tank body is made of plastic would allow the tank body to shrink by heat with the passage of time, disadvantageously, the accuracy of a joint portion where the annular member and the tank body (plastic container) are joined together could hardly be improved.
Furthermore, the cover-mounting structure as shown in
In order to avoid such an erroneous identification, at a stage after the fuel tank 40 is submerged in the water tank 57 and before pressure-regulated air is introduced therein, you should wait until the enclosed hollow space 52 becomes filled with water flown through very small gaps, for example, a gap 58 between the mounting part 49 and the cover 41, which necessarily results in an extended period of time for completion of the test. Moreover, even in this instance, if air in the enclosed hollow space 52 could not have been removed, bubbles derived from the air remaining in the enclosed hollow space 52 could possibly appear during the test; therefore, erroneous identification could not be avoided in any event.
The present invention was made to solve the above-described problems, and is directed to provide a cover-mounting structure of a plastic container in which the layer structure of a barrier layer provided in the plastic container is not affected, a high fastening strength is exercised between an opening provided in the plastic container and a cover, a good and secure sealing performance can be achieved, the accuracy and strength of a portion where a cover and a tank body are joined together will not lower with the passage of time, an annular member can be mounted with improved accuracy, and a submergence leak test can be performed easily with excellent accuracy within a shortened period of time.
A cover-mounting structure of a plastic container according to the present invention is a cover-mounting structure of a plastic container having a cover for closing an opening provided in a plastic container body at least part of which is made of a barrier material, wherein a portion of the plastic container where the opening is provided has a flange portion; the cover-mounting structure of the plastic container comprising: a recess provided annularly along a peripheral edge of the opening at an outside of the plastic container body, with an annular member being embedded integrally in the recess; the cover resting against the flange portion to close the opening; a seal provided between the flange portion and the cover to prevent a leak; and an annular retainer fastened to the annular member while resting against an external surface of the cover.
In this cover-mounting structure of a plastic container having a construction as described above, a seamless annular member is embedded in a portion around an opening of a tank body made of plastic to form an integral part thereof, and thus the strength of fastening between the plastic tank body and the cover can be improved.
Further, an annular member assumes an undivided ring-shaped geometry with no local rigidity variation point that would be involved at seams of a ring-shaped geometry, and thus good hermetical sealing performance between the tank body and the cover can be stably achieved.
Further, an annular member is not cut into an external wall of the tank body made of plastic so as not to sever a barrier layer of the plastic tank body, and thus the possibility of affecting a layer structure thereof can be eliminated.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a plurality of bolts for fastening the retainer are provided protrusively in the annular member.
In this cover-mounting structure of a plastic container having a construction as described above, insert bolts are provided protrusively in an annular member, and with nuts screwed on the bolts, a retainer can be firmly fastened; thus, the strength of fastening between the plastic tank body and the cover can be improved.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a screw hole is provided vertically in the annular member.
In this cover-mounting structure of a plastic container, a screw hole is provided vertically in an annular member, and with a bolt screwed into the screw hole, a retainer can be firmly fastened; thus, the strength of fastening between the plastic tank body and the cover can be improved.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials.
In this cover-mounting structure of a plastic container having a construction as described above, an annular member and a retainer for fixing the annular member are formed of metal materials, and thus the retainer can be firmly fastened, so that the strength of fastening between the plastic tank body and the cover can be improved.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a thread is formed on an outer or inner cylindrical surface of the annular member.
In this cover-mounting structure of a plastic container having a construction as described above, a thread is formed on an outer or inner cylindrical surface of an annular member, and thus the annular member can be fastened firmly to a retainer, so that the strength of fastening between the plastic tank body and the cover can be improved.
The cover-mounting structure of a plastic container according to the present invention may comprise: an outer rib projecting upwardly from an outer edge of a top surface of the flange portion; and an inner rib projecting downwardly from an undersurface of an outer edge portion of the cover toward the top surface of the flange portion, wherein the seal is provided in a space defined between the outer rib and the inner rib; and wherein the outer rib comes into contact with the undersurface of the outer edge portion of the cover when the cover is placed over the opening.
In this cover-mounting structure of a plastic container having a construction as described above, an outer rib comes into contact with a cover prior to an inner rib, which lightly touches or does not touch a flange portion, and thus the outer rib can be brought into secure and close contact with the cover; further, a space for providing a seal can be made between the outer rib and the inner rib, and thus excellent hermetical sealing performance can be achieved. Moreover, an inner rib does not strongly press a surface where a seal is placed, and thus deformation of the surface where the seal is placed can be prevented so that good hermetical sealing performance can be achieved.
The cover-mounting structure of a plastic container according to the present invention may comprise: an outer rib projecting upwardly from an outer edge of a top surface of the flange portion; and a seal guide shaped like a letter L in cross section so as to conform to a shape of a corner at an inner edge of the top surface of the flange portion, wherein the seal is provided in a space defined between the outer rib and the seal guide.
In this cover-mounting structure of a plastic container having a construction as described above, a space is defined between an outer rib projecting upwardly from an outer edge of a top surface of flange portion, and a seal guide shaped like a letter L in cross section so as to conform to a shape of a corner at an inner edge of the top surface of the flange portion, and further a space where a seal is placed can be made between the outer rib and the seal guide; therefore, the outer rib can come into secure and close contact with the cover, so that good hermetical sealing performance can be achieved.
The cover-mounting structure of a plastic container according to the present invention may comprise: an outer rib projecting upwardly from an outer edge of a top surface of the flange portion; and a seal guide shaped like a letter L in cross section so as to conform to a shape of a corner at an inner edge of the top surface of the flange portion, wherein the seal is provided in a space defined between the outer rib and the seal guide, and wherein the seal guide is of a soft resin having a fuel barrier property against HDPE (high-density polyethylene) with solubility parameter of 11 or greater, or of a soft EVOH (alcohol copolymer).
In this cover-mounting structure of a plastic container having a construction as described above, the seal guide is of a soft resin having a fuel barrier property against HDPE (high-density polyethylene) with solubility parameter of 11 or greater, or of a soft EVOH (alcohol copolymer), and thus has an excellent flexibility and an excellent barrier property, so that a good hermetical sealing performance and an inhibitive effect of preventing HC (hydrocarbon) from being transmitted can be achieved as a sub-seal.
The cover-mounting structure of a plastic container according to the present invention may comprise a metal ring provided between an area of a top surface of an outer edge portion of the cover under which area the seal is placed and a surface of the retainer which presses the cover, wherein the metal ring has a spring tension acting in such a direction that the portion of the plastic container where the opening is provided is pressed by the cover.
In this cover-mounting structure of a plastic container having a construction as described above, a metal ring has a spring tension acting in such a direction that the portion of the plastic container where the opening is provided is pressed by the cover, and the spring tension serves to make up for the change in positioning and strength between the joined portions of the cover and a portion around the opening, and can thereby maintain a predetermined level of the positioning accuracy and adequate strength; therefore, the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover (mount plate) and the tank body can be prevented from lowering.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the retainer has a spring tension acting in such a direction that the portion where the opening is provided is pressed by the cover.
In this cover-mounting structure of a plastic container having a construction as described above, a retainer has a spring tension acting in such a direction that a portion where an opening is provided is pressed by a cover, and the spring tension serves to make up for the change in positioning and strength between the joined portions of the cover and a portion around the opening, and can thereby maintain a predetermined level of the positioning accuracy and adequate strength; therefore, the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover (mount plate) and the tank body can be prevented from lowering.
The cover-mounting structure of a plastic container according to the present invention may comprise a metal ring provided between an area of a top surface of an outer edge portion of the cover under which area the seal is placed and a surface of the retainer which presses the cover, wherein the metal ring has a spring tension acting in such a direction that the portion of the plastic container where the opening is provided is pressed by the cover, wherein pump fittings are integrally mounted in the cover.
In this cover-mounting structure of a plastic container having a construction as described above, pump fittings are integrally mounted in the cover, and thus no clearance remains between the pump fittings and the cover; therefore, the hermetical sealing performance between the cover (mount plate) and the tank body can be improved.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, and in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member.
In this cover-mounting structure of a plastic container having a construction as described above, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of an annularly arranged recess and an outer cylindrical end face of the annular member, and thus when the thermal contraction is completed after plastic molding, the outer cylindrical end face of the annular member and outer inside wall of the annular recess come into contact with each other. This allows the annular member and the plastic container body to be firmly joined together, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, and in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member, wherein the annular member is so shaped as to be kept from obstructing the thermal contraction of the plastic container, and includes a plurality of bolts provided protrusively at annularly arranged positions along a peripheral edge of the opening.
In this cover-mounting structure of a plastic container having a construction as described above, the metal annular member is so shaped as to be kept from obstructing the thermal contraction of the plastic container, and thus bending or deformation due to local internal shrinkage of thermally contracting plastic materials can be prevented, so that the metal annular member can be slid smoothly in the recess. Further, the metal annular member includes a plurality of bolts provided protrusively at annularly arranged positions along a peripheral edge of the opening, and thus a good hermetical sealing performance of the opening can be maintained, and positioning accuracy of the annular member can be improved.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, and in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member, and in the plastic container body thermally contracted after plastic molding, the outer inside wall of the recess and the outer cylindrical end face of at least one of the annular member and the bolts are in contact with each other.
In this cover-mounting structure of a plastic container having a construction as described above, the outer inside wall of the recess and the outer cylindrical end face of at least one of the annular member and the bolts are in contact with each other, and thus no clearance remains between the annular member and the outer inside wall of the recess, which allows the annular member and the plastic container body to be firmly joined together, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, wherein in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member, and wherein in the plastic container body after plastic molding, a bottom surface of the space is in a position lower than bottom surfaces of the annular member and the bolts.
In this cover-mounting structure of a plastic container having a construction as described above, the bottom surface of the space formed in the recess is in a position lower than bottom surfaces of the annular member and the bolts, and thus the outer cylindrical end faces of the bolts can be brought into close contact with the inside wall of the recess, which serves to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member and the plastic container body.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, wherein in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member, and wherein in the plastic container body thermally contracted after plastic molding, a drainage passage is provided in an external surface of the plastic container body to drain water that tends to stay in or around interfaces between the recess and the annular member and between the recess and the bolts.
In this cover-mounting structure of a plastic container having a construction as described above, a drainage passage is provided in an external surface of the plastic container body to drain water that tends to stay in or around interfaces between the recess and the annular member and between the recess and the bolts, and thus the interfaces between the bottom surfaces of the annular recess and the annular member and spaces around the interfaces are allowed to communicate by means of the drainage passage, which allows water to drain to the outside, so as to prevent the formation of rust, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member and the plastic container body.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that the annular member and the retainer are formed of metal materials, wherein in the plastic container body immediately after plastic molding, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of the recess and an outer cylindrical end face of the annular member, and wherein the annular member is insert-molded with a plastic material from which the plastic container body is molded to form the plastic container body.
In this cover-mounting structure of a plastic container having a construction as described above, the annular member is insert-molded with a plastic material from which the plastic container body is molded to form the plastic container body, and thus the annular member and the plastic container body can be mounted with improved accuracy, which provides effective countermeasures when collision or the like occurs.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a through hole is provided to allow a space formed on a side of the retainer facing the plastic container body by fastening the retainer to the annular member to communicate with outside.
In this cover-mounting structure of a plastic container having a construction as described above, when the plastic container is submerged into a water tank during a submergence leak test, water is allowed to flow through the through hole to fill up the space for a short period of time. Accordingly, no extra time to wait is required from submergence of the plastic container into the water tank to introduction of pressure-regulated air, and therefore the time for testing can be reduced. Moreover, the evolution of bubbles derived from air in the space during the test can be prevented so as not to make an erroneous identification as described above. Consequently, the submergence leak test can be performed with improved accuracy.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a through hole to allow a space formed on a side of the retainer facing the plastic container body by fastening the retainer to the annular member to communicate with outside is provided in the retainer.
In this cover-mounting structure of a plastic container having a construction as described above, the through hole is provided in the retainer, and assuming that the bottom of the plastic container faces toward downward while the cover is located on its top, the through hole allows the space to immediately communicate at its top. Therefore, air that was in the space at the time of submergence of the plastic container into the water tank is discharged swiftly through the through hole by which the space communicates at its top. As a result, in the submergence leak test, the evolution of bubbles derived from air in the space during the test can be prevented without fail, and the submergence leak test can be performed with much more improved accuracy.
The cover-mounting structure of a plastic container according to the present invention may be characterized in that a through hole to allow a space formed on a side of the retainer facing the plastic container body by fastening the retainer to the annular member to communicate with outside is provided between the annular member and an external wall of the plastic container body to which the annular member is fastened, or between the retainer and the annular member.
In this cover-mounting structure of a plastic container having a construction as described above, the through hole is provided which allows the space to immediately communicate at its bottom, and thus when the plastic container is raised from the water tank after the submergence leak test has been carried out, water with which the space is filled can be discharged swiftly through the through hole. Accordingly, the process for drying the plastic container after the test can be performed with increased ease, and corrosion of constituent parts, which would result from residual water after the test, can be prevented.
Further, even if the plastic container is submerged into water in normal times of use, water flowed into the space can be drained through the through hole; thus corrosion of constituent parts, which would otherwise result from submergence in normal times of use, can also be prevented.
Further, in a case where another through hole which allows the space to immediately communicate at its top is provided in addition to the through hole which allows the space to immediately communicate at its bottom, when water is discharged through the through hole which allows the space to immediately communicate at its bottom after a submergence leak test has been carried out, the pressure of air flowed into the space pushes water in the space, so that the water can be discharged more swiftly. Accordingly, a process for drying the plastic container after the test can be performed with further increased ease, and corrosion of constituent parts, which would result from residual water after the test, can be prevented more effectively. Furthermore, corrosion of constituent parts, which would result from submergence in normal times of use, can also be prevented with a high degree of reliability.
A description will be given one by one of embodiments of a cover-mounting structure of a fuel tank according to the present invention with reference to the drawings.
The annular member 8 is provided in a manner that allows the tank outside wall 2a to become recessed and tucked up around an inner periphery of the annular member 8 so that the annular member 8 is held by the tank body 2. A separately provided retainer 9 made of metal is formed in a manner that allows one end portion (inner peripheral portion) of the retainer 9 to come into contact with an outer edge portion 1a of the cover 1 serving to hermetically close the opening 7 while the other end portion (outer peripheral portion) of the retainer 9 is in contact with the annular member 8, thereby fastening the cover 1 to the tank body 2. In the end portion (outer peripheral portion) of the retainer 9 is provided a retainer hole 9a through which a bolt 11 is to be inserted.
As shown in
A description will now be given of the cover-mounting structure of a fuel tank having the above construction in operation. A shown in
Since a predetermined number of bolts 11 are embedded in the annular member 8 that is mounted along the outside wall provided around the opening 7 so that the bolts 11 upwardly protrude respectively from substantially evenly spaced positions, each bolt 11 is fitted in the retainer hole 9a provided in one end portion (outer peripheral portion) of the retainer 9 and the other end portion (inner peripheral portion) of the retainer 9 comes into contact with the outer edge portion 1a provided at an outer edge of the cover 1. Nuts 13 are then screwed on the bolts 11, so that the cover 1 is fixed so as to hermetically close the opening 7.
As described above, the annular member 8 that is insert-molded in the tank body 2 made of plastic is a metal member, and the bolts 11 that are embedded integrally in this annular member 8 made of metal are metal members as well; therefore, the retainer 9 that is a metal member can be fastened with the nuts 13 so that the cover 1 can be fixed and kept in good and close contact with a portion around the opening 7 of the plastic tank body 2.
In
As shown in
A description will now be given of the cover-mounting structure of a fuel tank having the above construction in operation. As shown in
Since a predetermined number of bolts 31 are upwardly inserted and fitted in the annular member 38 that is mounted along the outside wall provided around the opening 37, so that the bolts 31 protrude respectively from substantially evenly spaced positions, each bolt 31 is fitted in the retainer hole 39a provided in one end portion (outer peripheral portion) of the retainer 39 and the other end portion (inner peripheral portion) of the retainer 39 comes into contact with the outer edge portion 1a provided at the outer edge of the cover 1. Nuts 33 are then screwed on the bolts 31, so that the cover 1 is fixed so as to hermetically close the opening 37.
As described above, the annular member 38 that is insert-molded in the tank body 32 made of plastic is a metal member, and the bolts 31 that are inserted and fitted in this annular member 38 made of metal are metal members as well; therefore, the retainer 39 that is a metal member can be firmly fastened with the nuts 33 so that the cover 1 can be fixed and kept in good and close contact with a portion around the opening 37 of the plastic tank body 32.
In
As shown in
A description will now be given of the cover-mounting structure of a fuel tank having the above construction in operation.
As shown in
A predetermined number of the bolts 41 are upwardly inserted and fitted in the annular member 48 that is mounted along the outside wall provided around the opening 47, so that the bolts 41 protrude respectively from substantially evenly spaced positions; each bolt 41 is fitted in the retainer hole 49a provided in one end portion (outer peripheral portion) of the retainer 49 and the other end portion (inner peripheral portion) of the retainer 49 comes into contact with the outer edge portion 1a provided at the outer edge of the cover 1. Nuts 43 are then screwed on the bolts 41, so that the cover 1 is fixed so as to hermetically close the opening 47.
As described above, the annular member 48 that is insert-molded in the tank body 42 made of plastic is a metal member, and the bolts 41 that are inserted and fitted in this annular member 48 made of metal are metal members as well; therefore, the retainer 49 that is a metal member can be firmly fastened up with the nuts 43 so that the cover 1 can be fixed and kept in good and close contact with a portion around the opening 47 of the plastic tank body 42.
In
As shown in
A description will now be directed to the cover-mounting structure of a fuel tank having the above construction in operation. As shown in
In the annular member 58 that is mounted along the outside wall provided around the opening 7 are provided the screw holes 58a at predetermined positions that are substantially evenly spaced out around the circumference of the annular member 58. Retainer holes 59a provided in one end portion (outer peripheral portion) of a retainer 59 are aligned with these screw holes 58a and the other end portion (inner peripheral portion) of the retainer 59 is brought into contact with the outer edge portion 1a of the cover 1. Thereafter, bolts 51 are screwed into the screw holes 58a, and the cover 1 is thereby fixed so as to hermetically close the opening 57.
As described above, the annular member 58 that is insert-molded in the tank body 52 made of plastic is a metal member, and the screw holes 58a that are provided in the annular member 58 made of metal are metal members as well; therefore, the retainer 59 that is a metal member can be firmly fastened up with the bolts 51 so that the cover 1 can be fixed and kept in good and close contact with a portion around the opening 57 of the plastic tank body 52.
In
As shown in
In
In
As shown in
A description will now be directed to the cover-mounting structure of a fuel tank having the above construction in operation. As shown in
Since the internal thread 89b provided in the downwardly bent outer cylindrical portion 89a of the retainer 89 engages in the external thread 88a provided in the outer cylindrical surface of the vertical riser portion 88b of the annular member 88 that is mounted along the outside wall provided around the opening 87, the cover 1 can be fixed so as to hermetically close the opening 87 by screwing the retainer 89 on.
As described above, the annular member 88 that is insert-molded in the tank body 82 made of plastic is a metal member, and thus the retainer 89 that is a metal member is screwed on, so that the cover 1 can be fixed and kept in good and close contact with a portion around the opening 87 of the plastic tank body 82.
In
As shown in
A description will now be directed to the cover-mounting structure of a fuel tank having the above construction in operation. As shown in
Since the internal thread 98a is provided in the annular member 98 that is mounted along the outside wall provided around the opening 97, this internal thread 98a engages in the external thread 99a provided in one end portion (outer peripheral portion) of the nut 99. Thereafter, the external thread 99a is engaged with and screwed on the internal thread 98a, and the cover 1 is thereby fixed so as to hermetically close the opening 97.
As described above, the annular member 98 that is insert-molded in the tank body 92 made of plastic is a metal member, and can thus be firmly fastened with the external thread provided in the outer cylindrical surface of the nut 99 that is a metal member. Accordingly, the cover 1 can be fixed and kept in good and close contact with a portion around the opening 97 of the plastic tank body 92. Hereupon, on a top surface of the nut 99, recessed portions are provided, though not illustrated, in at least two positions thereof, and the nut 99 can be fastened by using a predetermined jig.
Although some preferred embodiments have been described above, it is to be appreciated that the present invention is not limited to the above-described embodiments, and modifications may be made as appropriate which fall within the scope of the present invention without departing the spirit thereof. For example, in the aforementioned embodiments, a discussion is extended on the premise that the retainer provided has an annular shape, but the retainer is not necessarily annular, and may have the shape of a solid piece.
Around an outside wall provided around the opening 107, an annular member 108 that is larger in diameter than this opening 107 and made of metal is provided. A separate retainer 109 made of metal is provided in such a manner that one end portion (outer peripheral portion) of the retainer 109 is in contact with the annular member 108 while the other end portion (inner peripheral portion) of the retainer 109 is in contact with an outer edge portion 101a of the cover 101 that closes the opening 107. The retainer 109 is fastened with a plurality of bolts 111 and nuts 113, and the cover 101 is thereby fastened over the opening 107. In the present embodiment, eight pairs of bolts 111 and nuts 113 are employed to fasten the retainer 109.
A description will now be directed to the cover-mounting structure of a fuel tank having the above construction in operation. As shown in
As the cover 101 is placed and brought into contact with the outer rib 107f provided on the outer edge 107e of the flange portion 107a formed at an edge of the opening 107 of the tank body 102, the bolts 111 are fitted into retainer holes 109a provided in the one end portion (outer peripheral portion) of the retainer 109 and the other end portion (inner peripheral portion) of the retainer 109 comes into contact with the outer edge portion 101a of the cover 101. Thereafter, the nuts 113 are screwed on and the retainer can be fixed firmly onto the tank body 102 with the cover 101 closed hermetically.
The annular member 108 that is insert-molded in the tank body 102 made of plastic is a metal member, and the bolts 111 that are embedded integrally in this annular member 108 made of metal are metal members as well; therefore, the retainer 109 that is a metal member can be fastened up with the nuts 113. Accordingly, the cover 101 can be fixed and kept in good and close contact with a portion around the opening 107 of the plastic tank body 102.
Next, a description will be given of relative positioning of the outer rib 107f, the inner rib 101c and the seal 18 that are arranged so as to achieve the good and close contact.
In
As shown in
A description will now be directed to the cover-mounting structure of a fuel tank having the above construction in operation. A shown in
Although some preferred embodiments have been described above, it is to be understood that the present invention is not limited to the above-described embodiments, and modifications may be made as appropriate which fall within the scope of the present invention without departing the spirit thereof. For example, in the aforementioned embodiments, the outer rib is disposed in a radially outside position with respect to the inner rib, but the relative positioning may be configured vice versa.
A description will be given more in detail with reference to
To this end, a flange portion 147a is formed at an edge of the opening 147 provided in the tank body 142, and the seal 18 is provided annularly on a top surface 147b of the flange portion 147a, so that an interstice that could develop between the opening 147 and the cover 141 is hermetically sealed. Around the opening 147, an annular member 148 that is larger in diameter than the opening 147 and made of metal is provided. The annular member 148 is formed integrally with the tank body 142, and embedded therein by an undersurface 147c of the flange portion 147a, a recessed outside wall 147d provided around the opening 147, and a tank outside wall 142a. Accordingly, the annular member 148 is fixed, integrally with the tank body 142, around a peripheral edge of the opening 147 of the tank body 142. Bolts 151 are then screwed in the annular member 148, and the retainer 149 is fitted so as to have the bolts 151 inserted therein, and further the retainer 149 is fastened down by screwing nuts 152 from above on the bolts 151. Consequently, the retainer 149 is fixed on the annular member 148.
A guide rib 141d is provided on an undersurface of the discal cover 141 annularly so as to fit on an inner periphery defining the opening 147, and an outer cylindrical surface of a lower end portion of the guide rib 141d is chamfered to facilitate fitting. This guide rib 141d serves to position the cover 141 so that the cover 141 may not shift with respect to the opening 147. The undersurface 141b of the outer edge portion 141a of the cover 141 floats over an outer rib 147f formed at an outer edge of the flange portion 147a, due to support of the seal 18. Therefore, the outer rib 147f is provided annularly with a little clearance left from the undersurface 141b of the outer edge portion 141a of the cover 141. On an undersurface of the round cover 141 in a radially inside position nearer to the center thereof than that of the outer rib 147f, an inner rib 141c is provided with a clearance left from the top surface 147b of the flange portion 147a, or so disposed as to lightly touch the top surface 147b of the flange portion 147a. Thus, a space 16 is defined between the outer rib 147f and the inner rib 141c, and the seal 18 is placed annularly in the space 16. Further, along a vertical axis above the seal location on the top surface 147b of the flange portion 147a, the metal ring 10 is placed on the top surface 141a of the outer edge portion of the cover 141 and pressed down by the retainer 149.
Next, a description of the aforementioned metal ring 10 will be given below.
A description will now be directed to the cover-mounting structure of a fuel tank T having the above construction in operation. As shown in
On the other hand, the portion in the tank body 142 where the opening 147 is provided and the cover 141 are formed of plastic, and may therefore deform over time and could become unable to maintain its initially achieved accurate positioning and adequate strength between joined portions of the tank body 142 where the opening 147 is provided and the cover 141. Nevertheless, the metal ring 10 put between the retainer 149 and the cover 141 makes up for the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover 141 and the tank body 142 where the opening 147 is provided, with the help of spring tension of the metal ring 10, and can thereby maintain a predetermined level of positioning accuracy and adequate strength between the joined portions thereof. The deformation over time as described above is called “creep” strain, referring to the phenomenon in which plastic deformation progresses gradually with the lapse of time due to the application of sustained stress. To address this phenomenon, the spring tension of the metal ring 10 presses the cover 141 supported by the seal 18 in a floating manner. Even after the top surface 147b of the flange portion 147a or the undersurface 141b of the outer edge portion 141a of the cover 141 becomes so deformed as to assume a hollowed surface shape as a result of the creep strain, such a shape resulting from the creep strain may be conformed to so that the amount of compression of the seal (O-ring) 18 may be preserved, which makes it possible to inhibit the decrease of reaction force of the seal packing, and to thereby inhibit the decrease of hermetical sealing performance between the cover 141 and the tank body 142. The metal ring 10 that may operate as described above will come up for further discussion in detail.
As shown in
As shown in
The following discussion will be directed to a twelfth embodiment. The twelfth embodiment is different from the eleventh embodiment in that the twelfth embodiment has no metal ring 10, and that a retainer 169 that will be described later (see
In describing the twelfth embodiment, the same elements as in the eleventh embodiment are designated by the same reference numerals, and a description thereof will be omitted.
A description will be given more in detail with reference to
To this end, a flange portion 167a is formed at an edge of the opening 167 provided in the tank body 162, and the seal 18 is provided annularly on a top surface 167b of the flange portion 167a, so that an interstice that could develop between the opening 167 and the cover 161 is hermetically sealed. Around the opening 167, an annular member 168 made of metal is provided in such a manner as described in relation to the eleventh embodiment. Bolts 171 are screwed in this annular member 168, and the retainer 169 is fitted so as to have the bolts 171 inserted therein, and further the retainer 169 is fastened down by screwing nuts 172 from above on the bolts 171. Consequently, the retainer 169 is fixed on the annular member 168.
Under the discal cover 161, an outer rib 167f, an inner rib 161c, and a guide rib 161d are provided to define a space 16, and the seal 18 is provided in the space 16, in such a manner as described in relation to the eleventh embodiment.
Next, a description of the aforementioned retainer 169 will be given more in detail below.
A description will now be directed to the cover-mounting structure of a fuel tank T having the above construction in operation. As shown in
On the other hand, the portion in the tank body 162 where the opening 167 is provided and the cover 161 are formed of plastic, and may therefore deform over time and could become unable to maintain its initially achieved accurate positioning and adequate strength between joined portions of the tank body 162 where the opening 167 is provided and the cover 161. Nevertheless, the spring tension of the retainer 169 serves to make up for the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover 161 and the tank body 162 where the opening 167 is provided, and can thereby maintain a predetermined level of the positioning accuracy and adequate strength between the joined portions thereof. The spring tension of the retainer 169 makes it possible to conform to the deformed shape as a result of the creep strain of flange portion 167a and the outer edge portion of the cover 161, thereby inhibiting the hermetical sealing performance from lowering, as in the first embodiment. The retainer 169 that may operate as described above will come up for further discussion in detail.
The retainer 169, in which the slits 169a, 169a, . . . are made as shown in
As shown in
The fuel pump 6 (see
Since the cover 161 is mounted on the tank body 162 using a metal fastening means (retainer 169) to which a spring tension is applied, even when a joint portion between the fuel pump 6 and the tank body 162 has deformed over time, the seal 18 is invariably brought into close contact with the surface where the seal is placed under an adequate pressure, so that a predetermined sealing performance can be achieved.
Since a spring tension is applied to the entire perimeter of the metal fastening means (retainer 169), any partial decrease in sealing performance thereof can be avoided.
Moreover, since the spring elasticity, of the retainer itself or of a separate member such as a metal ring 10, is caused to reside in a joint portion to address the problem of decreasing reaction force of seal packing due to the creep strain, its spring-like portion conforms to the crept portion and the initially given reaction force of the seal packing can be preserved even after creeping has progressed, so that the decrease in hermetical sealing performance of the tank body 162 incorporating the fuel pump 6 can be prevented.
Although preferred embodiments have been described above, the present invention is not limited to the above-described embodiments, and modifications may be made as appropriate which fall within the scope of the present invention without departing the spirit thereof. For example, the aforementioned embodiments provides eight slits arranged annularly in the metal ring or retainer in order to enable the metal ring or retainer to exhibit a spring tension, but these slits may be cut either in radial directions at an inner circumference of its circular shape or in radial directions at an outer circumference of its circular shape. Further, the number of the slits may not be limited to eight.
The terms fuel tank and tank body used in describing the present embodiment refer respectively to plastic container and plastic container body defined in the claims. A cover will hereinafter be referred to as cover-like member.
As shown in
A description will now be directed to the cover-mounting structure of a fuel tank (plastic container) having the above construction in operation. Referring to FIGS. 18(a) and 18(b), the section of a portion around the opening 197 of the tank body 192 immediately after plastic molding (
As shown in
Although preferred embodiments have been described above, the present invention is not limited to the above embodiments, and any modifications may be made as appropriate without departing from the scope and spirit of the present invention. For example, only one drainage passage 192a is provided on the external surface of the tank body 192 in the present embodiment, but the number of the drainage passages 192a may be increased as appropriate. Further, the bolts provided in the annular member are not limited to particular embodiments in respect to whether the bolts have heads or not, or how the bolts are fastened to the annular member, as far as their screw thread portions are oriented upward. Furthermore, the present embodiment has been described on the premise that it is applied to a fuel tank of an automobile, but the applicable parts are not limited to the fuel tank of the automobile and, needless to say, generally include plastic parts shaped into a container.
A cover-mounting structure of a plastic container according to a fourteenth embodiment of the present invention will be described hereinafter with reference made to drawings as appropriate. Hereupon, the positions and directions will be represented with respect to the normal state of operation of the plastic container.
Referring now to
The fuel tank T has a round opening 217 on top of a tank body 212. A flange portion 217a is provided at an edge of the opening 217. A cover 211 for closing the opening 217 is discal, and on an inside thereof are provided a fuel feed passage for supplying an automotive engine with fuel fed from a pump module (not shown), a fuel recirculation passage through which unconsumed fuel flows back from the engine, and other components. The cover 211 is as large in diameter as to substantially cover the flange portion 217a when it is mounted on the tank body 212. An annular seal 18 is provided between the flange portion 217a and the cover 211. The seal 18 is not limited in material, and may be formed of, for example, a blend of acrylonitrile-butadiene rubber and polyvinyl chloride, or the like.
An annular member (hereinafter referred to as annular supporting part 218) is provided on an outside wall 212a of the tank body 212 so as to surround the opening 217. Provided in a gap between the supporting part 218 and the outside wall 212a of the tank body 212, on which the supporting part 218 is fixed, are a plurality of through holes 205, . . . , (for example, eight of which are provided in the present embodiment and among which six are illustrated) which are substantially evenly spaced along its circumference. Moreover, in the supporting part 218 are provided a plurality of bolts 221, . . . (for example, eight of which are provided in the present embodiment), which are located at positions substantially evenly spaced around its circumference but not coincide with the positions of the through holes 205, . . . and are fitted and held upright in holes 218a, . . . provided in the supporting part 218. Hereupon, the supporting part 218 may be fixed on the outside wall 212a of the tank body 212 by various means, which is not limited to a particular method but may include for example welding and the like. Moreover, the bolts 8, . . . may be fixed on the supporting part 218 by various means, which is not limited to a particular method but may include for example screwing and the like.
An annular retainer (hereinafter referred to as annular mounting part 219) includes an inner peripheral portion 219a to rest against the cover 211, and an outer peripheral portion 219c provided with retaining holes 219b, . . . through which bolts 221, . . . are to be inserted. The retaining holes 219b, . . . are fitted on the bolts 221, . . . while the cover 211 is being pressed down by the inner peripheral portion 219a, and the outer peripheral portion 219c is then fastened on the supporting part 218 using the bolts 221, . . . and the nuts 222, . . . , thereby allowing the cover 211 to be mounted on the fuel tank body 212. Moreover, along a bend 219d of the mounting part 219 are provided a plurality of through holes 206, . . . (for example, eight of which are provided in the present embodiment), which are substantially evenly spaced around its circumference.
The through holes 206, . . . are provided at locations as shown in
The materials of which the supporting part 218, mounting part 219, bolts 221, . . . and nuts 222 are formed are not limited, but may preferably be formed of metal in that the cover 211 is firmly fixed and its mount spot is resistant to deformation. Further, in order to prevent rust that would be formed when these metal parts are submerged in water during submergence leak test or the like, the metal to be used may preferably be antirust metal such as stainless steel or the like.
Next, a description will be given of procedural steps for mounting the cover 211 onto the fuel tank body 212 with reference to
First, the seal 18 is placed on top of the flange 217a around the opening 217, and the cover 211 is then placed on the seal 18. Further, the retaining holes 921b, . . . provided in the outer peripheral portion 219c of the mounting part 219 are fitted on the bolts 221, . . . while a top surface 211a of the outer edge portion of the cover 211 is being pressed down with the inner peripheral portion 219a of the mounting part 219. Subsequently, the nuts 222, . . . are screwed on the bolts 221, . . . , and the cover 211 is thereby mounted on the fuel tank body 212.
The following description will be directed to operation and advantageous effects of the cover-like member mounting structure of a fuel tank T according to the fourteenth embodiment of the present invention with reference to
In
When the cover 211 is firmly mounted on the fuel tank body 212, the seal 18 clamped between an undersurface 211b of the outer edge portion of the cover 211 and a top surface 217b of the flange portion 217a around the opening 217 is pressed so that a secure and good hermetical sealing performance can be achieved.
Next, a description will be given with reference to
Further, since the through holes 205 are provided between the supporting part 218 and the outside wall 212a of the fuel tank body 212 on which the supporting part 218 is fixed, the through holes 205 are provided so as to allow the space 207 to immediately communicate at its bottom. This allows water with which the space 207 is filled to be discharged swiftly through the through holes 205 when the fuel tank T is raised from the water tank after the submergence leak test has been carried out. Moreover, the through holes 205 are provided so as to allow the space 207 to immediately communicate at its top, and thus the pressure of air flowed into the space 207 pushes water in the space 207, so that the water can be discharged more swiftly. Accordingly, a process for drying the fuel tank 1 after the test can be performed with increased ease, and corrosion of constituent parts, which would result from residual water after the test, can be prevented.
A cover-mounting structure of a fuel tank 220 according to a fifteenth embodiment of the present invention will be described hereinafter with reference to drawings as appropriate. Hereupon, the fuel tank 220 corresponds to “plastic container” set forth in claims.
FIGS. 22(a) and 22(b) to which reference is made herein correspond to FIGS. 21(b) and 21(c) to which reference was made in describing the fourteenth embodiment;
As shown in
When the cover 225 is firmly mounted on the fuel tank body 221, a seal 28 clamped between an undersurface 225b of an outer edge portion of the cover 225 and a top surface 227b of a flange portion 227a around an opening 227 is pressed so that a secure and good hermetical sealing performance can be achieved.
The fuel tank 220 is provided with through holes 229 and through holes 230 as shown in
Further, the supporting part 223 is insert-molded in the recess 221b, and thus firmly joined with the fuel tank body 221. As a result, the hermetical sealing performance of the fuel tank 220 is improved.
The supporting part 223 is insert-molded with an allowance 232 for thermal contraction of the fuel tank body 221 provided as indicated by dashed lines in
Although a preferred embodiment has been described above, the present invention is not limited the above-described embodiment. For example, the bolts and nuts are used when the mounting part is fixed on the supporting part in the present embodiment, but the method of fixing the mounting part is not limited thereto, as far as the method allows the mounting part to be provided to extend out to the supporting part while pressing the cover from outside whereby the mounting part can be fixed on the supporting part.
The through holes as well are not limited to the above embodiments, as far as the holes allow the space formed on a plastic container body side of the mounting part to communicate with outside.
Although the above-described embodiment provides an annular seal between a flange portion provided around the opening of the plastic container body and the cover, the present invention is not particularly limited in terms of sealing means. For example, a cover having a sealing capability may be used to hermetically close the opening of the plastic container body to thereby prevent a leak.
In a cover-mounting structure of a plastic container according to the present invention, a seamless annular member is embedded in a portion around an opening of a tank body made of plastic to form an integral part thereof, and thus the strength of fastening between the plastic tank body and the cover can be improved.
In a cover-mounting structure of a plastic container according to the present invention, an annular member assumes an undivided ring-shaped geometry with no local rigidity variation point that would be involved at seams of a ring-shaped geometry, and thus good hermetical sealing performance between the tank body and the cover can be stably achieved.
In a cover-mounting structure of a plastic container according to the present invention, an annular member is not cut into an external wall of the tank body made of plastic so as not to sever a barrier layer of the plastic tank body, and thus the possibility of affecting a layer structure thereof can be eliminated.
In a cover-mounting structure of a plastic container according to the present invention, insert bolts are provided protrusively in an annular member, and with nuts screwed on the bolts, a retainer can be firmly fastened; thus, the strength of fastening between the plastic tank body and the cover can be improved.
In a cover-mounting structure of a plastic container according to the present invention, a screw hole is provided vertically in an annular member, and with a bolt screwed into the screw hole, a retainer can be firmly fastened; thus, the strength of fastening between the plastic tank body and the cover can be improved.
In a cover-mounting structure of a plastic container according to the present invention, an annular member and a retainer for fixing the annular member are formed of metal materials, and thus the retainer can be firmly fastened, so that the strength of fastening between the plastic tank body and the cover can be improved.
In a cover-mounting structure of a plastic container according to the present invention, a thread is formed on an outer or inner cylindrical surface of an annular member, and thus the annular member can be fastened firmly to a retainer, so that the strength of fastening between the plastic tank body and the cover can be improved.
In a cover-mounting structure of a plastic container according to the present invention, an outer rib comes into contact with a cover prior to an inner rib, which lightly touches or does not touch a flange portion, and thus the outer rib can be brought into secure and close contact with the cover; further, a space for providing a seal can be made between the outer rib and the inner rib, and thus excellent hermetical sealing performance can be achieved.
In a cover-mounting structure of a plastic container according to the present invention, an inner rib does not strongly press a surface where a seal is placed, and thus deformation of the surface where the seal is placed can be prevented so that good hermetical sealing performance can be achieved.
In a cover-mounting structure of a plastic container according to the present invention, a space is defined between an outer rib projecting upwardly from an outer edge of a top surface of flange portion, and a seal guide shaped like a letter L in cross section so as to conform to a shape of a corner at an inner edge of the top surface of the flange portion, and further a space where a seal is placed can be made between the outer rib and the seal guide; therefore, the outer rib can come into secure and close contact with the cover, so that good hermetical sealing performance can be achieved.
In a cover-mounting structure of a plastic container according to the present invention, the seal guide is of a soft resin having a fuel barrier property against HDPE (high-density polyethylene) with solubility parameter of 11 or greater, or of a soft EVOH (alcohol copolymer), and thus has an excellent flexibility and an excellent barrier property, so that a good hermetical sealing performance and an inhibitive effect of preventing HC (hydrocarbon) from being transmitted can be achieved as a sub-seal.
In a cover-mounting structure of a plastic container according to the present invention, a metal ring has a spring tension acting in such a direction that the portion of the plastic container where the opening is provided is pressed by the cover, and the spring tension serves to make up for the change in positioning and strength between the joined portions of the cover and a portion around the opening, and can thereby maintain a predetermined level of the positioning accuracy and adequate strength; therefore, the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover (mount plate) and the tank body can be prevented from lowering.
In a cover-mounting structure of a plastic container according to the present invention, a retainer has a spring tension acting in such a direction that a portion where an opening is provided is pressed by a cover, and the spring tension serves to make up for the change in positioning and strength between the joined portions of the cover and a portion around the opening, and can thereby maintain a predetermined level of the positioning accuracy and adequate strength; therefore, the change caused by the time-varying plastic materials in positioning and strength between the joined portions of the cover (mount plate) and the tank body can be prevented from lowering.
In a cover-mounting structure of a plastic container according to the present invention, pump fittings are integrally mounted in the cover, and thus no clearance remains between the pump fittings and the cover; therefore, the hermetical sealing performance between the cover (mount plate) and the tank body can be improved.
In a cover-mounting structure of a plastic container according to the present invention, a space to be allowed for thermal contraction of plastic is provided between an outer inside wall of an annularly arranged recess and an outer cylindrical end face of the annular member, and thus when the thermal contraction is completed after plastic molding, the outer cylindrical end face of the annular member and outer inside wall of the annular recess come into contact with each other. This allows the annular member and the plastic container body to be firmly joined, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member.
In a cover-mounting structure of a plastic container according to the present invention, the metal annular member is so shaped as to be kept from obstructing the thermal contraction of the plastic container, and thus bending or deformation due to local internal shrinkage of thermally contracting plastic materials can be prevented, so that the metal annular member can be slid smoothly in the recess. Further, the metal annular member includes a plurality of bolts provided protrusively at annularly arranged positions along a peripheral edge of the opening, and thus a good hermetical sealing performance of the opening can be maintained, and positioning accuracy of the annular member can be improved.
In a cover-mounting structure of a plastic container according to the present invention, the outer inside wall of the recess and the outer cylindrical end face of at least one of the annular member and the bolts are in contact with each other, and thus no clearance remains between the annular member and the outer inside wall of the recess, which allows the annular member and the plastic container body to be firmly joined, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member.
In a cover-mounting structure of a plastic container according to the present invention, the a bottom surface of the space formed in the recess is in a position lower than bottom surfaces of the annular member and the bolts, and thus the outer cylindrical end faces of the bolts can be brought into close contact with the inside wall of the recess, which serves to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member and the plastic container body.
In a cover-mounting structure of a plastic container according to the present invention, a drainage passage is provided in an external surface of the plastic container body to drain water that tends to stay in or around interfaces between the recess and the annular member and between the recess and the bolts, and thus the interfaces between the bottom surfaces of the annular recess and the annular member and spaces around the interfaces are allowed to communicate by means of the drainage passage, which allows water to drain to the outside, so as to prevent the formation of rust, serving to maintain a good hermetical sealing performance of the opening, as well as to improve positioning accuracy of the annular member and the plastic container body.
In a cover-mounting structure of a plastic container according to the present invention, the annular member is insert-molded with a plastic material from which the plastic container body is molded to form the plastic container body, and thus the annular member and the plastic container body can be mounted with improved accuracy, which provides effective countermeasures when collision or the like occurs.
In a cover-mounting structure of a plastic container according to the present invention, a through hole is provided to allow a space formed on a side of the retainer facing the plastic container body by fastening the retainer to the annular member to communicate with outside, and thus when the plastic container is submerged into a water tank during a submergence leak test, water is allowed to flow through the through hole to fill up the space for a short period of time. Accordingly, no extra time to wait is required from submergence of the plastic container into the water tank to introduction of pressure-regulated air, and therefore the time for testing can be reduced. Moreover, the evolution of bubbles derived from air in the space during the test can be prevented so as not to make an erroneous identification as described above. Consequently, the submergence leak test can be performed with improved accuracy.
In a cover-mounting structure of a plastic container according to the present invention, the through hole is provided in the retainer, and assuming that the bottom of the plastic container faces toward downward while the cover is located on its top, the through hole allows the space to immediately communicate at its top. Therefore, air that was in the space at the time of submergence of the plastic container into the water tank is discharged swiftly through the through hole by which the space communicates at its top. As a result, in the submergence leak test, the evolution of bubbles derived from air in the space during the test can be prevented without fail, and the submergence leak test can be performed with much more improved accuracy.
In a cover-mounting structure of a plastic container according to the present invention, the through hole is provided which allows the space to immediately communicate at its bottom, and thus when the plastic container is raised from the water tank after the submergence leak test has been carried out, water with which the space is filled can be discharged swiftly through the through hole. Accordingly, the process for drying the plastic container after the test can be performed with increased ease, and corrosion of constituent parts, which would result from residual water after the test, can be prevented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2002-355459 | Dec 2002 | JP | national |
| 2002-355462 | Dec 2002 | JP | national |
| 2003-002888 | Jan 2003 | JP | national |
| 2003-146032 | May 2003 | JP | national |
| 2003-180860 | Jun 2003 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP03/15599 | 12/5/2003 | WO | 9/8/2006 |
