Fuel hose resin coupling

Background of the Invention

1. Field of the Invention

The invention relates to a composite end with a plastic fuel hose Plastic coupling and more particularly to a plastic coupling that is constructed in such a way is that in the inner wall of the insertion tube portion of the coupling body, an O-ring is used.

The present invention is based on Japanese Patent Application Nos. Hei 10-94899, the content of which is part of the present application by reference.

2. Description of the Prior Art

In the present specification, the term "means electrical damage to the Plastic "that current flows in the contact region of various structural members, that the plastic material is damaged. includes the electrical damage to the plastic electrolytic damage and thermal damage (Joule effect) a.

For example, Hei 4-224394, the Japanese Patent Publication No.. A literature agency that does not relate to the invention in a special way, but a Litera turstelle, showing the general art and the present with reference to the Description is incorporated.

A fuel hose made of plastic generally requires material properties such as Resistance to gasoline, compared to gasohol resistance to a Permeability of gasoline and to moisture. Therefore has a tubular body<b>12</b> in general, a multilayer structure as shown in <b>Fig.</b> 1 shown.

For example, the fuel hose made of plastic is arranged as follows:

A body ply <b>14</b> made of polyamide, for example nylon <b>11</b>, nylon <b>12</b> or like, with excellent resistance to gasohol and resilience against moisture permeability and having flexibility. Next is within the body position <b>14</b> an inner layer (the innermost layer <b>16</b>) Fluoroplastic material ausgebil det, where both its properties, such as resistance to gasoline and cons ance to over a Benzinpermeabilität much better than nylon <b>11</b> or nylon <b>12</b> is (s. US Patent No. 5,383,087).

The inner surface of the plastic fuel tube, through the Fuel flow are electrostatically charged. It is a necessary, therefore, the amount to limit the electrostatic charge to a predetermined value to the In occur to prevent electrostatic problems.

For this purpose, the inner layer <b>16</b> formed of a material whose electrical Resistance is lower than a predetermined value (usually 1 × 10^8th Ohm) so that static electricity can be easily generated, so that the static electricity (charge) can flow to other electrically conductive parts.

That is, in the inner layer <b>16</b> static electricity generated is through a nipple <b>20</b> an electrically conductive quick connection part and by a metal tube <b>22</b>, that with the quick coupling part <b>18</b> connected and grounded (as <b>Fig.</b> 2) dissipated.

The design of the quick coupling part <b>18</b> is such that in the inner cylindrical wall the insertion tube section <b>26</b> the coupling body <b>24</b> O-rings are used. This serves the metal pipe with the coupling <b>18</b> to combine in a single operation.

On the other hand, the electrically conductive quick coupling part with respect to the (Injection molded it can) assembly work, productivity and weight rundown primarily of plastic. To the static electricity (charge) to discharged, the quick coupling part consists mainly of a plastic having a Volume resistivity under 10⁶ Ohm × cm or a surface resistance of less than 10⁶Ohm.

It has been shown that the existing plastic quick coupling part, the one having electrical resistance, electrically deteriorated at an accelerated manner or is damaged electrically within the meaning of the above definition.

Summary of the Invention

In view of the foregoing, an object of the invention is a plastic to provide coupling for a fuel hose, wherein the coupling body is electric only slightly degraded.

The inventors have conducted intensive research for solving the above-described performed and found that the cause of problem for the electrical Ver deterioration of the plastic coupling is as follows:

In the discharge path (or Ladungsabflußweg) of the inner layer <b>16</b>, The coupling body <b>24</b> and the metal tube <b>22</b> is a gap for the joining of the metal tube <b>22</b> and the coupling <b>18</b> is provided between the metal tube <b>22</b> and the insertion tube section <b>26</b> the coupling body <b>24</b> provided. The gap between the metal tube<b>22</b> and the insertion tube section <b>26</b> with sealing rings <b>28</b> sealed. Because the radio tion of the sealing ring <b>28</b> it is not possible, that is its electrical resistance as small, that static electricity can flow. To the electrical resistance small to ma Chen, it is necessary that a large amount of carbon black is used to the elec tric resistance of the O-ring lower; to seal the gap well, it is is not convenient to use a large amount of soot.

Therefore, by the inner layer behaves <b>16</b> the coupling body <b>24</b> migratory charge as follows: When the metal tube <b>22</b> due to the vibration of the vehicle in Point contact is made with the coupling body, flows into the contact area between coupling body <b>24</b> and metal pipe <b>22</b> Electricity. This current is a factor of the degradation (or decomposition) of the plastic coupling body <b>24</b> accelerated.

In this context, it has been found that if the electrical resistance the coupling body lies in a predetermined range, the current Ver the deterioration of the coupling body <b>24</b> accelerated in the contact area between coupling body <b>24</b> and metal tube does not flow. As a result, the following described plastic coupling for a fuel hose devised.

The plastic coupling according to the invention for a fuel hose includes an O- Ring, the cylindrical inner wall of the pipe in the insertion area of ​​a clutch body is inserted. A specific feature of the plastic coupling is that the electric resistance of the coupling body between 10⁶ and 10¹⁰ Ohm × cm be respect of the volume resistivity or 10⁶ until 10¹⁰ Ohm with respect to the surface resistivity is.

In this context it is advantageous that the coupling body, an electrically conductive comprises a thin layer because the surface resistivity of the coupling body can be easily accommodated in the prescribed range.

In addition, it is advantageous that an electrically conductive elastic member at the bottom of Stage of the insertion tube portion is arranged. In this case, it is advantageous that the specific volume and the surface resistivity of the elastic member are smaller than that of the coupling body, because the discharge path then properly is maintained.

Further features and advantages of the invention will become apparent from the following detailed profiled description of preferred embodiments together with the accompanying Drawings.

Brief Description of Drawings

In the drawings:

<b>Fig.</b> 1 a cross section of a fuel tube;

<b>Fig.</b> 2 shows a section of a plastic coupling, which an embodiment of the inven tion forms;

<b>Fig.</b> 3 shows a section of another assembly example of the plastic coupling and

<b>Fig.</b> 4 is a section of the plastic coupling on the an electrically conductive layer is trained.

Detailed description of the preferred embodiment

An invention made of resin or resin or plastic clutch will present mainly with reference <b>Fig.</b> 2 described.

The plastic coupling of the invention is a resin, synthetic resin or plastic material existing fuel hose (or tube body) <b>12</b> connected and internal in the cylindrical wall of the pipe insertion portion <b>26</b> the coupling body <b>24</b> O-rings <b>28</b> inserted or fitted. That is, it is a quick connect component or a Quick coupling.

In the illustrated embodiment, the hose body <b>12</b> a two-ply Structure having a body ply <b>14</b> and an innermost layer of tubes, namely an inner layer <b>16</b>; but it can also be built up layer or a panel of three to six layers have multilayer structure. In<b>Fig.</b> 2, reference numeral <b>25</b> a hose protection of elastomer.

An insulating plastic, the body ply the <b>14</b> forms can be prepared from plastic jedwelchem be, having the necessary for the fuel hose properties; virtue example is Nylon <b>11</b> or nylon <b>12</b> used, its resistance to Gasohol is excellent, which has a small coefficient of water absorption, flexibility is low and withstanding temperatures well.

Next, there is the inner layer <b>16</b> within the tubular body ply <b>14</b> preferably from an electrically conductive fluoroplastic material.

When the body ply <b>14</b> is made of nylon and the inner layer <b>16</b> fluoroplastic there is between the body ply <b>14</b> and the inner layer <b>16</b> normally an adhesive layer since these materials are not joined by welding can.

An especially important feature of the plastic coupling of the invention is that the electric resistance of the coupling body <b>14</b> with regard to the specific Volu menwiderstandes between 10⁶ and 10¹⁰ Ohms × cm, preferably 10⁷-10⁹ Ohm × cm is or in terms of surface resistivity <b>10</b>⁶-<b>10</b>¹⁰ Ohms (preferably 10⁷-10⁹ Ohm) is.

When the electric resistance of the quick connector part the upper limit value exceeds, then the resistance is too high, so that inside the tube static electricity generated by the quick-connecting member <b>18</b> to the metal tube <b>22</b> can migrate. When the electric resistance, however, lower than the lower Limit is flowing in the discharge a large current; that is, the point of contact between the coupling body <b>24</b> and the metal tube <b>22</b>So that the synthetic resin in the Quick connecting part electrically deteriorated.

The quick coupling part can the prescribed range of electrical resistance Prior comprise as follows: It can be made of a hard plastic material be obtained by electrically conductive filler material with hard plastic resin material is mixed. Alternatively, as in<b>Fig.</b> 3 shown, an electrically conductive thin layer on the surface of the coupling body <b>24</b> be formed, is made of the hard plastic material.

Preferably, the hard plastic material Polyazethal (POM), polyamide (PA), poly vinyl chloride (PVC), polyester or polypropylene. Preferably, the electrically conductive Fillers, carbon black, graphite or stainless steel and the highly electrically conductive metal is example as copper, silver or gold.

The application of the electrically conductive layer <b>30</b> can electrically by applying conductive ink, by printing with electrically conductive ink by electric Galvani tion, vacuum deposition, combustion chemical vapor deposition, sputtering or ion plating ge happen. In view of the productivity is advantageously applying electrically conductive ink or the printing of electrically conductive ink used.

The electrically conductive paint / ink is a mixture of electrically conducting filler and Binders such as synthetic resin, and an additive solvent, wherein the mixture cures to form an electrically conductive ink or layer. The electrically conductive Filler may have a composition as described above have. In the case of electrically conductive film carbon black or graphite is preferably used, or of the non-expensive is, since it is not necessary that the electrically conductive film has a high electrical Conductivity.

Further, the binder, namely the plastic material, a good adhesion to the Körperla ge <b>14</b> on. When the body ply nylon<b>11</b> and nylon <b>12</b> there is the resin For example, preferably polyurethane, acrylic resin (including the type of Irradiation is UV-cured), and alkyd resin, because their weather resistance is good.

The surface of the coupling body <b>24</b> includes the electrically conductive layer. Of the Coupling body can thus be easily manufactured such that its specific top surface resistivity <b>10</b>⁶-<b>10</b>¹⁰ Ohms.

According to <b>Fig.</b> 3 is an electrically conductive, elastic member <b>32</b> the bottom of the stage <b>27</b> of Pipe insertion portion <b>26</b> arranged. Both the specific volume and the surface resistivity of the elastic member <b>32</b> are smaller than those of the coupling body <b>24</b>, Providing a direct and stable discharge path through electrical Line may be formed (including cargo movement). Preferably both the specific volume and the surface resistivity of the elastic member <b>32</b> not less than 0.1% and less than 10% of the coupling body <b>24</b>, The electric line is therefore evenly from the Kupp ment body <b>24</b> the metal tube <b>22</b>; ie, in the coupling body<b>24</b> is no charge stored, and it is positive, the flow of a large current through the touch area of ​​the coupling body <b>24</b> with the metal tube <b>22</b> prevented.

In the present embodiment, the elastic member <b>32</b> of electrically conductive rubber; the invention thereto or thereby not limited. The Member may be a coil spring or a leaf spring of metal or electrically conductive hard plastic material.

In the fuel hose Plastic coupling according to the invention is the specific Surface resistance of the coupling body between 10⁶ and 10¹⁰ Ohms × cm and surface resistivity between 10⁶ and 10¹⁰ Ohm. The invention Plastic coupling has the following functions, effects and advantages:

When the electric resistance of the quick-connection part <b>18</b> the upper limit value exceeds the electrical resistance is extremely high, so that the inside of the Hose static electricity generated difficult by the quick coupling part <b>18</b> to the metal tube <b>22</b> can migrate. When the electric resistance against it under the lower limit value, flows into the coupling body <b>24</b> under the metal tube <b>22</b> in the discharge path, a high current, so that the quick coupling part <b>18</b> electric may be deteriorated or damaged.

In the fuel hose Plastic coupling according to the invention of the plastic body hardly electrically damaged.

Since the surface of the coupling body is provided with an electrically conducting layer is, it is possible in a simple manner to form the coupling body so as to having surface resistivity described above.

In the fuel hose Plastic coupling according to the invention is an electrically conductive elastic member arranged at the bottom of the stage of the pipe insertion section. This Feature allows the discharge motion a direct and stable Entla dungsweg form.

Further, the electric line of the coupling body is carried gleichmä the metal tube larly. Further, the coupling body is not charged. The problem that a strong Power in the point of contact between the coupling body <b>24</b> and metal pipe <b>22</b> flows, can be positively prevented. Therefore can be effectively prevented that the electrical properties of the plastic coupling body deteriorate or the Material is damaged.

The invention has in its preferred form with specific details described; Construction details, the combination and arrangement of parts can however, be changed without departing from the spirit or scope of the following claims departing.