JP4381552B2 - Structure of small part fixing part for plastic fuel tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a small component fixing portion for a synthetic resin fuel tank, and particularly to a structure for fixing a small component such as a pump module in an opening provided in the synthetic resin fuel tank.
[0002]
[Prior art]
A fuel tank formed by blow molding of a synthetic resin material is known (see Japanese Patent Publication No. 7-17160). In order to assemble small parts such as a pump module in such a synthetic resin fuel tank, a protruding part with a male thread formed on the outer peripheral surface is provided on the outer wall of the tank, and a union nut is screwed into the male thread to form a small part. In general, a structure that tightens is used.
[0003]
On the other hand, in blow molding, there is a tendency that the thickness of the portion that first contacts the inner surface of the mold when air is blown tends to be the largest, but this is the last contact with the inner surface of the mold during blow molding. The protruding part of the outer tank wall is meant to be the thinnest. That is, according to the conventional structure in which the external thread is formed on the projecting portion, it is troublesome to secure the strength as the attachment portion of the small part.
[0004]
Increasing the thickness of this portion to ensure strength leads to a relative increase in the thickness of other portions, leading to an increase in weight. In addition, it is conceivable to insert mold the tank body after forming the attachment part of the small part as a separate member. However, this complicates the manufacturing process, and the strength of the joint part between different materials becomes a problem. Therefore, it is not necessarily optimal for improving reliability.
[0005]
[Problems to be solved by the invention]
In other words, according to the conventional technology, it is difficult to satisfy the contradictory demands of reducing the weight of the tank body and ensuring the strength of the small part mounting portion, resulting in the impediment to the design freedom of the synthetic resin fuel tank. It was.
[0006]
The present invention has been devised to solve such problems of the prior art, and its main purpose is to make small parts due to deterioration over time without causing deterioration in manufacturability and excessive increase in weight. An object of the present invention is to provide a structure of a small component fixing portion for a synthetic resin fuel tank capable of suppressing a decrease in accuracy of an attachment portion and a strength against an external force.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, an engagement portion provided integrally with an opening of a blow molded synthetic resin fuel tank and a fastening member paired with the engagement portion are provided. Further, as a structure for fixing a small part via a seal member, the engaging portion is provided in a cylindrical portion (12) formed by immersing the wall of the tank (1) inward, The fastening member is provided with an annular portion (14) fitted to the inner peripheral surface of the cylindrical portion, and the structure of the small component fixing portion for the synthetic resin fuel tank is provided.
[0008]
In this way, since the part where the seal member is installed comes into contact with the inner surface of the mold at an early stage while supporting the small parts, only the thickness of the part is increased without increasing the thickness of the entire tank. Can do.
[0009]
In particular, a radially inward flange (7a) is provided at the inner end in the axial direction of the cylindrical portion, and an opening (7) is formed with the inner peripheral edge of the flange, and a radially outward flange is provided at a portion located outside the opening of the small part. If (6a) is provided and the sealing member (8) is sandwiched between the two flanges, only the thickness of the seal portion can be easily and efficiently increased.
[0010]
In addition to these, a female screw (11) is formed on the inner peripheral surface of the cylindrical portion, and a male screw (13) screwed to the female screw is formed on the annular portion. The small parts can be fixed to the tank by the above.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0012]
FIG. 1 shows an entire fuel tank T to which the present invention is applied. The fuel tank T has a main tank 1 that functions as a fuel storage tank, and a main tank 1 in which the suction port of the fuel pump 2 is always submerged below the liquid level by blocking the fluctuation of the liquid level due to the movement of the vehicle. And a sub-tank 3 provided in the tank. The main tank 1 is provided with a connection port 4 with an oil supply pipe that opens at an appropriate position of the vehicle body.
[0013]
The sub-tank 3 includes a bottomed cylindrical container body 5 provided with a fuel inlet at an appropriate position, and a lid plate 6 that is liquid-tightly fitted to the opening of the container body 5. It is inserted into the main tank 1 through an opening 7 provided in the upper wall. 2, the radially outward flange 6a formed on the cover plate 6 is liquid-tight via the seal member 8 with respect to the radially inward flange 7a formed on the opening 7 of the main tank 1. To be joined.
[0014]
A fuel pump 2 is accommodated inside the container body 5. A discharge passage 9 connected to the discharge port of the fuel pump 2 and a return passage 10 through which excess fuel from the engine recirculates are integrally fixed to the lid plate 6.
[0015]
The main tank 1 is seamlessly formed by blow molding, and a cylindrical portion 12 provided with an internal thread 11 on the inner peripheral surface is integrally formed in a shape in which a part of the upper wall is immersed inward. Yes. And the bottom wall of this cylindrical part 12 is excised by secondary processing, thereby inserting the radially inward flange 7a for supporting the radially outward flange 6a of the cover plate 6 and the sub tank 3 into the main tank 1. Opening 7 is formed.
[0016]
A seal member 8 such as an O-ring or gasket is sandwiched between a radially inward flange 7a whose inner peripheral edge forms an opening 7 and a radially outward flange 6a of the cover plate 6, and a male screw 13 is formed on the outer peripheral surface thereof. By screwing the formed holding ring 14 having an annular shape into the female thread 11 on the inner peripheral surface of the cylindrical portion, the seal member 8 is appropriately compressed between the outward flange 6a and the inward flange 7a, and the desired sealing performance is obtained. It is done.
[0017]
A stopper ring comprising an axial end face 15 (see FIG. 3) that contacts the upper surface of the inward flange 7a of the cylindrical portion 12 or an outward flange 16 (see FIG. 4) that contacts the outer surface of the upper wall of the main tank 1 or the like. 14, it is possible to manage the tightening margin of the press ring 14 when fixing the sub tank 3 to the main tank 1 and to make the pressure contact force applied to the seal member 8 constant.
[0018]
In this way, since the material comes into contact with the mold at the initial stage of blow molding, that is, at a stage where the wall thickness is somewhat large, it is relatively easy to increase the thickness of the small component engaging portion. In addition, by forming the internal thread in the thick portion, it is easy to ensure the strength of the threaded portion, so that the occurrence of rattling of the threaded portion due to the thinning due to deterioration over time such as creep phenomenon is also eliminated.
[0019]
As shown in FIG. 5, not only the screw means but also the presser ring 14 is connected to the presser ring 14 with a claw 18 that hooks on the engaging projection 17 that protrudes from the inner peripheral surface of the cylindrical part 12. The pressing ring 14 may be coupled to the cylindrical portion 12 by using the elastic deformation of the synthetic resin material itself by pressing.
[0020]
【The invention's effect】
As described above, according to the present invention, during blow molding, the portion for supporting the small parts and installing the seal member comes into early contact with the inner surface of the mold. It can be increased without increasing the overall wall thickness. Therefore, coupled with the fact that there is no need to insert a separate insert mold, it has a great effect on increasing the strength and sealing performance of the small component fixing part without increasing the weight of the entire tank or reducing the manufacturability. Can be played.
In particular, if the seal member is sandwiched between the radially inward flange provided in the cylindrical part and the radially outward flange provided in the small part, only the thickness of the seal part is easily and efficiently increased. Therefore, a higher sealing performance can be obtained without causing an increase in weight.
Furthermore, if the male screw of the annular portion is screwed to the female screw on the inner peripheral surface of the cylindrical portion, the small parts can be fixed to the tank by screw connection, so that the manufacturability can be further improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a synthetic resin fuel tank to which the present invention is applied. FIG. 2 is an enlarged sectional view of an essential part of the invention. FIG. 3 is an enlarged sectional view of an essential part showing another embodiment. The principal part expanded sectional view which shows another form [FIG. 5] The principal part expanded sectional view which shows another form [Description of code]
DESCRIPTION OF SYMBOLS 1 Main tank 2 Fuel pump 3 Sub tank 4 Connection port 5 Container body 6 Cover plate 6a Outward flange 7 Opening 7a Inward flange 8 Sealing member 9 Discharge passage 10 Return passage 11 Female screw 12 Cylindrical part 13 Male screw 14 Holding ring 15 Axial end surface 16 Outward flange 17 Engagement protrusion 18 Claw

Claims (3)

A small part is fixed via a seal member between an engagement part provided integrally on the outer periphery of the blow molded plastic fuel tank opening and a fastening member paired with the engagement part. A structure for
The engaging portion is provided in a cylindrical portion formed by immersing the tank wall inward,
The structure of the small component fixing | fixed part with respect to the synthetic resin fuel tank characterized by the said fastening member being provided with the cyclic | annular part fitted by the internal peripheral surface of the said cylindrical part. A radially inward flange is provided at the axially inner end of the cylindrical portion, and the opening is defined by the inner peripheral edge of the flange, and a radially outward flange is provided at a portion located outside the opening of the small part. The structure of the small component fixing portion for the synthetic resin fuel tank according to claim 1, wherein the seal member is sandwiched between both flanges. 3. The small part for the synthetic resin fuel tank according to claim 1, wherein a female screw is formed on an inner peripheral surface of the cylindrical portion, and a male screw that is screwed to the female screw is formed in the annular portion. The structure of the fixed part.

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