The present utility model refers to a sealtight electrical connector assembly against fuel infiltration, particularly suitable for use in electrical connections located inside the fuel tanks of automobile vehicles of the bifuel kind, preferably motorcycles, which use blends of alcohol and gasoline in different proportions.

Description of the State of the Art

With the development of the automobile industry, it is increasingly common to have electrical devices in vehicle environments exposed to liquid or vapor fuel. At the same time, there is a growing trend to use alcohol as fuel both in pure form, and also blended with gasoline, because it is a renewable fuel. However, contact of the electrical devices with alcohol can be harmful owing to the highly corrosive nature of this fuel.

Alcohol and/or gasoline-powered vehicles generally use a fuel level sensor arranged inside the fuel tank, which is responsible for supplying an electrical signal corresponding to the fuel level present in the vehicle tank. The signal generated is normally sent to a control panel or to a cluster of the vehicle. Powering this type of level sensor is by electrical power cables that traverse the tank, being immersed in fuel or else exposed to fuel in vapor form, and are connected to the electrical terminals .of the sensor through electrical connectors. The signal generated by the sensor is also sent to the panel or to the cluster by means of electrical cables connected to the sensor that are exposed to the fuel in the tank.

Owing to the fact that these level sensors and the respective electrical power and data transmission cables are in direct contact with the fuel, the connection between the sensor and the cables needs to have some kind of sealing that prevents the entry of fuel into the electrical terminals of the sensor, principally in cases where the use of alcohol as a predominant portion of the bifuel blend is foreseen.

Infiltration of fuel inside the connector is problematic due to the fact that the contact of the electrical power and data transmission cables of the sensor with the fuel causes chemical and/or electrolytic corrosion thereof and consequently the electrical contact becomes intermittent.

Some models of electrical connectors are already known for environments with the presence of fuel, having the aim of solving the problem of infiltration of fuel in the cables, thus reducing the corrosion of the electrical terminals.

Brazilian patent document PI 0603987-1 filed in the name of Robert Bosch do Brasil refers to an electrical connector for fuel pumps and level sensors for vehicles of the bifuel type, preferably four-wheeled vehicles, which has two insulated chambers for the electrical terminals of the connector, in order to avoid corrosion by electrolysis between the two terminals caused by the difference in potential between the terminals in an environment containing alcohol. The connector has inner seals between the inner walls of the insulated chambers and the terminals, and outer seals on the outer walls of the insulated chambers and the female connection part.

" The drawback of this connector is that it provides efficient sealing only in the connection region between the male and female parts of the connector. Moreover, this connector does not prevent fuel infiltration by capillarity in the cables, which is the phenomenon whereby the fuel penetrates into the gap between the protective cover of the cable and the metallic conductor wires and runs through this space as far as the terminal where the metallic wires are crimped to a metallic contact pin. Therefore, this fuel infiltration does not occur only in the engagement region between the electrical contacts of the cables and the electrical device to be powered, but rather along the entire length of the cable that is in contact with the fuel in vapor or liquid form. This connector of the state of the art provides no mechanism that prevents the fuel already infiltrated into the gap between the protective cover of the cable and the metallic wires from reaching the cable contact terminals.

Patent document US 6.837.744 B2 refers to an electrical connector, for aircraft fuel pumps sealtight against fuel penetration. This connector is formed by a metallic housing that has a glass lid for electrical insulation connected to one of its ends. The lid has tubular insulating ceramic supports. The connector pins traverse openings in the lid, and the tubular supports, and are connected to electrical cables. In this connection region, the pins also have an outer coating of fluoropolymer, and a tubular insulating extension made of insulating material. This connector has a sealing structure to ensure insulation between the various terminals of the connector which is rather complex, and additionally makes use of materials such as glass and insulating ceramic which are less resistant than polymeric materials, and do not allow the manufacture of the connector by injection of the terminals. Additionally, this document does not provide for any prevention of fuel infiltration in the cables which occurs by capillarity. .

Brazilian patent document PI 0603637-6 discloses a sealtight connector overinjected to an electric fuel pump which is formed by a body injected with two separate electrical terminals, which are connected to spools and soldered to wire harnesses. The entire assembly is overinjected with a plastic coating, such that the electrical terminals are insulated inside separate circular chambers. This connector does not prevent fuel infiltration into the cables by capillarity either.

Patent document GB 2438551 discloses an electrical connector for use in submersible pumps, particularly in oil drilling environments. The connector is formed by a body that has insulated orifices for each terminal, and the end of each of the terminals is connected to a guide pin. Additionally, for sealing the pins, an elastomeric sealing is applied, along with a PEEK (poly-ether-ether-ketone) insulation sleeve, a threaded spigot and O- rings on the threaded spigot. These rings act as sealants for incasing the tails with sockets in a fitting of the male-female kind. Furthermore, the connector itself has sealing rings in the outer periphery of its body, to help seal the connector.

This connector is applied between the wire harness and the part to be connected thereto, and is therefore not applied between the connection terminals and the housing. This document does not suggest that the connector be directly overinjected in the connection region between the cables and the pins either. This connector structure requires the use of a pre-molded box having two openings for the passage of cables, and various additional components to seal a connection between the cables and the terminals. The use of various parts with very precise sizes so that they can cooperate together efficiently and guarantee the sealing renders the structure too complex and subject to faults. Additionally, according to this document, the cables are connected directly to the terminals, there being no interface part between them to assist in sealing against capillarity.

It can therefore be noted that no document from the state of the art has been designed to provide an electrical connector that presents good sealing performance both to prevent corrosion by electrolysis due to the exposure of two terminals with opposite polarities in an alcoholic medium, and to prevent infiltration by capillarity of the fuel that penetrates inside the protective cover of the cable.

Objectives of the Utility Model

A first task of the present utility model is to provide a connector for electrical connections immersed in fuel, such as those used in fuel level sensors, that prevents the infiltration of fuel into its terminals both by capillarity and by penetration into the male-female fitting, in order to reduce chemical and/or electrolytic corrosion, and consequently eliminate contact intermittence.

Another objective of the present utility model is to reduce the complexity of the electrical connections of fuel level sensors, allowing the pump or connector of the power cables to be substituted in insulation and, consequently, in a simpler and more economical way.

Brief Description of the Utility Model

The objectives of the utility model are achieved by way of a sealtight electrical connector assembly, comprising:

a female part having at least two reception chambers and two electrical contacts housed inside the female part, each contact being aligned with a respective reception chamber

a male part having a housing that houses the connection end of at least two electrical cables, each connection end being arranged inside an insulated chamber of the housing having a connection exit opening, the insulated chambers being encasable in a sealtight manner in a respective reception chamber of the female part, establishing insulated electrical contact of the electrical contacts housed inside the female part with the electrical cables,

characterized wherein

the male part comprises at least two metallic pins each having:

- a body with at least an outer recess to house a sealing ring, and at least a segment having a greater diameter than the opening of the insulated chambers, the segment being arranged near to the connection exit opening of the housing,

- a protrusion of the body with a lesser diameter than the exit opening, and the protrusion traverses the exit opening and is connected to one of the electrical cable connection ends inside one of the insulated chambers of the housing,

and at least one sealing ring mounted by interference in each recess of the body of the pin, making pressure contact on the inside of a reception chamber of the female part.

The connector assembly preferably comprises at least two electrical terminals, each terminal being connected to a respective pin, and a sleeve applied on each of the electrical terminals at least in the region of the connection with the pin.

The connector assembly according to the utility model may comprise at least two sealing rings respectively mounted by interference on at least two recesses of the pin body, the sealing rings being made of elastomeric material.

The connection ends of the electrical cables and the pins may be crimped and tinned and the pins may be soldered to the electrical terminals.

The insulated chambers of the male part preferably have on their outer surface a fixing clip with a respective reception chamber of the female part.

Brief Description of the Drawings The present utility model will now be described in further detail, based on an example of an embodiment represented in the drawings. The drawings show:

Figure 1 - is a perspective view of the male part of the sealtight electrical connector assembly according to the present utility model;

Figure 2 - is an enlarged view of the male part of the sealtight electrical connector assembly according to the present utility model, showing all the components of this part separately;

Figure 3 - is a cross-section view of the male part and part of the female part of the sealtight electrical connector assembly according to the present utility model;

Figure 4 - is a perspective view of the sealtight electrical connector assembly according to the present utility model, showing the male part and the female part separately, before they are connected; and

Figure 5 - is a perspective view of the sealtight electrical ^* connector assembly according to the present utility model, showing the male part and the female part connected together.

Detailed Description of the Figures

Figures 1 to 3 show a preferred embodiment of the male part 20, also referred to as wire harness, of the sealtight electrical connector assembly according to the present utility model. This male part 20 is connected to a female part 30 shown in figures 4 and 5, forming an electrical connector assembly which is immune to corrosion of the electrical contacts by electrolysis and at the same time sealtight from fuel infiltration by capillarity, thus preventing the fuel that penetrates into the gap between the protective cover and the metallic wires of the electrical cables reaches the electrical terminals of the connector.

This electrical connector assembly is, therefore, particularly suitable for use in electrical devices that are arranged in environments in contact with, liquid or vapor fuel, such as fuel level sensors used in the automobile industry. It is also particularly advantageous to apply this connector assembly to electrical connections of motorcycles, due to their smaller dimensions.

As can be seen in figures 4 and 5, the female part 30 of the connector assembly is composed of a framework that has at least two hollow reception chambers 11 , wherein each of these chambers is destined to provide an individual and separate fitting with a respective insulated chamber 3 of the male part 20 of the connector assembly. Each of these reception chambers 11 acts as a guide for connecting an electrical contact that passes through the insulated chamber 3 of the male part 20 with a respective electric contact (not illustrated) of a device housed inside the framework of the female part 30. Each of the electrical contacts of this device should be aligned with a respective reception chamber 11 of the female part, so that, when the male part 20 is engaged with the female part 30, the connection ends of the electrical cables 2 in the male part are directly guided through the reception 11 to be connected to the electrical contacts of the device housed in the female part. This electrical device, not illustrated either, can be a fuel level gauge.

In alternative embodiments of the utility model, if the connector is applied to any kind of device that using more than two connection pins, the female part 20 may comprise more than two insulated chambers 11 , each acting as a guide for connecting an electrical contact with a respective contact of the device housed inside the framework.

As can be seen in figures 1 to 3, inside the male part 20 the connection ends 2 of two electrical cables are arranged, and may be, for example, power cables. Each of the connection ends of the cables is connected to an electrical pin 4. A housing made of polymeric material is overmolded on the connection ends 2 of the cables, in the connection region with the electrical pins. Therefore, by this overinjection molding, an insulated chamber 3 is formed around the connection region of each cable connection end 2 with the respective pin 4, so that each cable connection end is arranged inside an insulated chamber 3 of the male part, preventing the electrical terminals with, opposite polarities from being exposed to the same environment containing alcohol, in order to avoid corrosion by electrolysis. These insulated chambers 3 have a connection exit opening 14 at one end, and at the opposite end, are linked together by a central part of the housing. The insulated chambers 3 have a suitable shape for connection on the exit opening 14 side to the respective reception chambers 11 of the female part of the connector assembly, forming a positive union between the male part and the female part, which is sealtight from liquid or gas fuel penetration. This connection between the male part and the female part acts as a guide for the electrical power cables to establish insulated electrical contacts with the electrical contacts of a device housed inside the female part. The insulated chambers 3 of the male part have on their outer surface at least one and preferably two fixing clips 15, for example clips per leg, to help fix these insulated chambers 3 with the respective reception chamber 11 of the female part. Hence, when the male part 20 is pressed against the female part 30, these clips automatically snap over the edges of the reception chambers 11 of the female part, fixing the connector assembly.

Overinjection of the housing is carried out by placing the cable connection ends 2 and the pins 4 already connected to each other inside a mold with the desired housing shape. The mold is subsequently filled with polymeric material, which takes on the form of this mold.

In the preferred embodiment of the utility model, the cable connection ends 2 and the pins 4 are crimped and tinned. Thus, the contact of these parts with the fuel does not cause a deterioration of this electrical connection, avoiding the occurrence of failures in this connection.

The electrical pins 4 are made of metallic material and have a body 6, which has at least a segment 8 with a greater diameter than the opening 14 of the insulated chambers 3. The pins also have a protrusion of the body 5 with a lesser diameter than the opening 14 of the insulated chambers. This protrusion 5 is connected to one connection end of an electrical cable inside one of the insulated chambers 3 of the male part 20, such that the entire length of the protrusion 5 of each of the pins is also housed inside one of the insulated chambers 3.

Additionally, the pin is arranged in such a way in the male part that the opening 14 of each of the insulated chambers is near or preferably in contact with a segment 8 of the pin 4 that has a greater diameter than the opening 14 itself. The pin is made of metallic material which is impermeable, contrary to plastics which allow liquid permeation through the material. Thus, this proximity or potential contact between the pin 8 and the opening of the housing 14 makes the fuel that leaves through the opening 14 be diverted and run over the sides of the pin, to a space between the reception chamber 11 and body of the pin 6, as shown by the arrows in figure 3.

As can be seen more clearly in figures 1 to 3, the body 6 of the pin 4. also has at least an outer recess 7 to house a sealing ring. In the preferred embodiment of the utility model shown in these drawings, the body 6 of the pin has two outer recesses 7 to house a sealing ring in each one. The sealing rings 9 used in this connector are O-rings made of elastomeric material, which have a lesser diameter than the diameter of the recesses 7 of the body of the pin, and that consequently are mounted by interference in these recesses, providing a sealtight contact to fuel between the rings and the recesses of the pin.

When the male part 20 is connected to the female part 30, the body 6 of the pins is housed inside a respective reception chamber 11 of the female part. Furthermore, the O-rings, when mounted on the respective recesses 7 of the body, have an outer diameter so as to allow these rings 9 to make contact with the inside of the respective reception chamber 11 of the female part, also creating sealing pressure against the reception chamber 11 , to prevent the passage of fuel. Thus, the application of the sealing rings 9 between the electrical pin 4 and the reception chamber prevents the passage of fuel in a space that may exist between the reception chamber 11 and the pin 4 of the male part, creating sealing against fuel originating from infiltration by capillarity, which runs around the pin 4 and reaches this inner region of the connector. This sealing performed by the rings 9 prevents the fuel infiltrated by capillarity from reaching the connection between the power cables and the contact terminals of an electric device arranged inside the framework of the female part 30. In alternative embodiments of the utility model, the connector assembly may comprise just one sealing ring 9 mounted on a recess 7 of the pin 4, or else more than two sealing rings each mounted on a recess 7 of the pin. The first sealing ring 9 located nearer the insulated chambers 3 of the male part 20 creates the primary sealing against the fuel. The other rings create auxiliary sealing for any fuel which may traverse the first ring 9.

Additionally, the opposite end of the protrusion 5 of each of the pins 4 is preferably connected to an electrical terminal 10, normally by soldering. A sleeve 12 is also applied on each of the electrical terminals 10, extending at least over the connection region with the pin 4. This sleeve essentially has the function of providing a support and a mechanical protection of the connection soldered between the terminals 10 and the pins 4. Since in the connector assembly according to the present utility model, the sealing against fuel infiltration capillarity is performed by the sealing rings 9 arranged on the pin 4, in the region between the insulated chambers 3 of the male part and the reception chambers 11 of the female part, so there is a very minor risk that the fuel will reach the electric contact terminals. This is why there is no need for the sleeves 12 to provide additional sealing against fuel on the terminals.

Therefore, when the connector assembly is in mounted state, that is, with the male part 20 connected to the female part 30, it has surprising sealing performance against infiltration by fuel capillarity, and is at the same time immune to the wear of the electrical terminals by electrolysis.

The fitting between the male 20 and female 30 parts associated to the sealing rings 9 on the pins 4 arranged in the engagement region prevents the penetration of fuel in the connection between these two parts 20 and 30 and consequently on the terminals of the electric device housed inside the female part. At the same time, the use of separate chambers 3, 11 for connection between each of the terminals of the connector prevents corrosion of these terminals by electrolysis, which normally occurs due to the presence of two terminals with opposite polarities in a medium containing fuel with a high alcohol content. Due to this association of characteristics, the sealing performance of this connector is superior to those already known in the state of the art.

An improved understanding of the utility model can be obtained by analyzing the arrows of figure 3, which represent the fuel that penetrates between the protective cover and the electric cable conductor wires. Normally, this fuel runs towards the connection end 2 of the cables, rapidly reaching the electrical terminals of the connector, because in general these terminals are connected directly to the cable connection ends. The contact of fuel with the terminals causes corrosion thereof and, consequently, failures in the electrical contacts.

In the connector assembly of the present utility model, the metallic pin 4 is used as an additional connection interface part between the electrical terminals 10 and the connection ends 2 of the cables.

As can be seen by the arrows illustrated in figure 3, the fuel infiltrated by capillarity reaches the connection ends 2 of the cables, and the protrusion 5 of the pin which is connected to the cable, as far as the exit opening 14 of the insulated chamber 3 of the male part 20. However, upon reaching the exit opening 14, the fuel comes into contact with the segment 8 of the body of the pin 5, which has a greater diameter than the opening 14. Since the pin is made of metal, which is a material that is not liquid permeable, the fuel is then prevented from traversing the body 6 of the pin 4. So, this fuel that traverses the opening 14 is diverted by the segment 8 of the pin to the space between the reception chamber 11 and body of the pin 6, until it reaches at least a first sealing ring 9. However, as the sealing ring 9 creates sealing pressure both against the inner face of the reception chamber 11 of the female part, and against the surface of the recess 7 pin 4, then the fuel is prevented from passing to the terminals 10 and, potentially, also to the part connected with this connector assembly. Therefore, the sealing rings 9 are responsible for the effective sealing of the connector assembly. In the embodiment of the present utility model, two sealing rings 9 are applied on the pin 4, and the first ring located nearer to the opening 14 of the male part 20 acts as the primary sealing of the fuel, and the second ring, arranged beneath the first, is an auxiliary sealing to the first ring.

Having described an example of a preferred embodiment, it must be understood that the scope of the present utility model encompasses other potential variations, and is only limited by the content of the claims appended hereto, including possible equivalents therein.