JP2002234353A - Synthetic resin-made vent valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure both high heat welding characteristics and high strength in higher level. SOLUTION: This synthetic resin-made vent valve 1 comprises: a valve body 4; a head part 5 formed to an upper end of the valve body; and a gasoline barrier part 10 formed to a surface layer of the head. The vent valve 1 is formed in multiple colors. In this vent valve 1, when a hose connecting port 8 of elbow shape comprising a vertical part 6 and a horizontal part 7 is arranged to the head part, a strut 17 integrally formed to the head part is inserted to the vertical part. Accordingly, flexural rigidity particularly in the vertical part of the hose connecting port is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin vent valve and, more particularly, to a synthetic resin vent valve which is joined to an opening of a synthetic resin tank by heat welding.

[0002]

2. Description of the Related Art Since rust prevention and weight reduction are easy and high productivity is obtained, the tendency to use a fuel tank formed by blow molding a synthetic resin material has recently been increasing. Such a synthetic resin fuel tank is provided with accessory parts such as a filler neck and a vent valve, and the joint with the tank is preferably formed of a material that can be welded by heating.

By the way, high-density polyethylene (hereinafter referred to as HDPE) which can be heated and welded is a hydrocarbon (hereinafter referred to as HPE).
C) is low in impermeability (hereinafter referred to as barrier property), and is not suitable for use as it is in gasoline tank accessories from the viewpoint of preventing air pollution.

[0004] In order to suppress the permeation of HC, it is preferable to use a material having a high barrier property such as an ethylene vinyl alcohol copolymer (hereinafter referred to as EVOH). Since the adhesiveness is low, if the accessory is formed of a gasoline barrier material, it is difficult to satisfy the bonding strength between the tank body and the accessory.

In order to cope with such inconvenience, a tank body is formed of a laminated material obtained by sandwiching a film-like gasoline barrier material with a heat-weldable material, and an accessory is formed of a gasoline barrier material. A structure in which only the heat-welded portion is formed by two-color molding with a heat-weldable material has already been proposed.

[0006]

Incidentally, it is necessary to provide a hose connection port in the vent valve. To simplify the entire structure, the hose connection port is formed by two-color molding with a flange portion which is a heat welding portion. It is preferable to integrally mold by a method. However, it is difficult for the weldable material to sufficiently satisfy the relatively high strength required for the hose connection port.

In addition, since the welded portion becomes unsightly when the molten resin flows out during pressurization, it is preferable to provide a concave portion for allowing the molten resin to flow into the inner peripheral side of the flange. However, when forming a flange portion made of a heat-weldable material at the upper end of the valve body by two-color molding, it is necessary to insert an intermediate mold for forming a concave portion, but the intermediate mold obtains a predetermined accuracy. For this purpose, high rigidity is required, and clearance from the valve body is required for the purpose of die-cutting. Therefore, it is difficult to form the annular concave portion at the base of the flange by two-color molding.

The present invention has been devised in order to solve such problems of the prior art, and the main object of the present invention is to provide a high degree of compatibility between heat welding property and strength. To provide a synthetic resin vent valve.

[0009]

In order to achieve such an object, claim 1 of the present invention comprises a valve body (4),
A head portion (5) formed at an upper end of the valve body portion,
A gasoline barrier section (1) formed outside the head section
0), and a multi-color molded synthetic resin vent valve (1) having an elbow-shaped hose connection port (8) comprising a vertical portion (6) and a horizontal portion (7) in the head portion. In this case, the column (17) integrally formed with the head portion is inserted into the vertical portion.

[0010] In this case, the bending rigidity of the hose connection port, particularly at the vertical portion, is increased by the support pillar.

In particular, if the step (18) in which the side where the horizontal portion is extended is provided at the upper end of the column is provided, the elbow-shaped portion when the column is inserted is provided. Can equalize the volume balance of meat

According to a third aspect of the present invention, there is provided a multi-color valve having a valve body, a head formed at an upper end of the valve body, and a gasoline barrier formed outside the head. In the molded synthetic resin vent valve,
An annular covering portion (16) for covering the outer peripheral surface of the upper end portion of the valve main body portion at the base on the lower surface side of the radially outward flange portion (9) provided on the head portion so that the lower surface is heat-welded to another component. Is provided.

With this configuration, the thickness of the intermediate mold (13) can be increased by the amount of the annular covering portion.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a vent valve constructed according to the present invention. In FIG. 1, the vent valve 1 includes a valve body 4 composed of a float valve 2 and a cylindrical case 3 containing the same, a head 5 formed at the upper end of the cylindrical case 3, and a center of the head 5. An elbow-shaped hose connection port 8 comprising a vertical portion 6 protruding from the portion and a horizontal portion 7 extending from the upper end of the vertical portion 6;
It comprises a radially outward flange 9 formed on the outer circumference of the head 5, a head 5, a hose connection port 8, and a gasoline barrier 10 formed on the surface of the flange 9.

In this vent valve 1, a cylindrical case 3 is first molded from a relatively high-strength material such as polyacetal, and then the cylindrical case 3 is inserted into another mold (see FIG. 2). ), The molten HDPE is injected into the cavity C to form the head portion 5, the hose connection port 8, and the flange portion 9 into a second shape, and the head portion 5, the hose connection port 8, and the flange portion 9 are separated. Gasoline barrier section 10 made of EVOH on its surface
Was obtained by tertiary molding.

As shown in FIG. 2, during secondary molding, upper dies 1 each divided by a plane through which the axis of cylindrical case 3 passes.
By sandwiching an intermediate mold 14 having an annular protrusion 13 on the inner periphery between the first mold 1 and the lower mold 12, the resin melted at the time of heat welding flows into the base on the lower surface side of the flange 9. An annular concave portion 15 is formed to allow the recess.

The upper mold 11 and the lower mold 12 can be opened and closed in the left-right direction or the front-back direction in FIG. Then, after opening the lower mold 12, the intermediate mold 14 is moved downward in the axial direction so as to be extracted from the cylindrical case 3.

An appropriate gap G is provided between the inner peripheral surface of the intermediate mold 14 and the outer peripheral surface of the cylindrical case 3 to facilitate die-cutting. An annular covering portion 16 is formed on the lower surface of the base of the flange portion 9. By forming the coating portion 16, the thickness t of the intermediate mold 14 for forming the annular concave portion 15 is set to a size that can secure rigidity that can maintain a close state with the upper surface of the lower mold 12. It can be.

A column 17 integrally formed with the head portion 5 is inserted at the root of the vertical portion 6 at the head portion 5 in the elbow-shaped hose connection port 8. Thereby, the bending rigidity of the vertical portion 6 at the hose connection port 8 is increased. Further, by providing the pillars 17, for example, when a gate (not shown) is provided at a position facing the head portion 5, the resin flow to the vertical portion 6 is suitably guided, and as a result, surface defects such as burrs Is suppressed.

At the upper end of the support 17, a step 18 having a lower side from which the horizontal portion 7 extends is provided. This allows
Equalizes the volume of HDPE material flowing into the extended side and the non-extended side of the horizontal portion 7 at the connection between the vertical portion 6 and the horizontal portion 7 to prevent the occurrence of surface defects such as sink marks. are doing.

The internal passages P of both the vertical portion 6 and the horizontal portion 7 are formed by inserting a punching core (not shown) in advance.

[0023]

As described above, according to the first aspect of the present invention, since the bending rigidity of the hose connection port, particularly the vertical portion, is increased by the support, the heating of the vent valve which is heated and welded to the synthetic resin fuel tank is performed. A large effect can be achieved while achieving high levels of weldability and strength.

In particular, by adding a step provided at the upper end of the column to the above configuration, that is, by adding a step provided at the upper end of the column, the volume of the wall of the elbow-shaped portion when the column is inserted can be equalized. This is effective in preventing the occurrence of surface defects such as.

According to the third aspect of the present invention, the annular mold for covering the outer peripheral surface of the upper end portion of the valve body is provided at the base on the lower surface side of the flange, so that the intermediate mold corresponds to the annular cover. Can be increased, that is, it is possible to impart a required rigidity to the intermediate mold. Therefore, the annular concave portion can be formed at the base of the flange portion by two-color molding, and a great effect can be obtained in simplifying the structure of the synthetic resin vent valve.

[Brief description of the drawings]

FIG. 1 is an elevational view of a vent valve according to the present invention with a partial cutaway.

FIG. 2 is a longitudinal sectional view of a main part showing a state of being inserted into a mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vent valve 4 Valve main part 5 Head part 6 Vertical part 7 Horizontal part 8 Hose connection port 9 Flange part 10 Gasoline barrier part 14 Intermediate mold 16 Coating part 17 Prop 18 Step

Claims (3)

[Claims] 1. A multi-color molded synthetic resin vent having a valve body, a head formed at an upper end of the valve body, and a gasoline barrier formed outside the head. A valve, wherein the head portion is provided with an elbow-shaped hose connection port composed of a vertical portion and a horizontal portion, and a column integrated with the head portion is inserted into the vertical portion. Synthetic resin vent valve. 2. The synthetic resin vent valve according to claim 1, wherein a step is provided at an upper end of the support post, the step having a lower side at which the horizontal portion extends. 3. A synthetic resin vent having a valve body, a head formed at an upper end of the valve body, and a gasoline barrier formed outside the head. A valve, wherein the head portion is provided with a radially outward flange portion whose lower surface is heat-welded to another component, and the valve main body is provided at a root of the lower surface side of the flange portion with respect to the valve main body portion. A synthetic resin vent valve provided with an annular covering portion for covering an outer peripheral surface of an upper end portion of the vent valve.