WO2013178727A1

WO2013178727A1 - Over-molded electrical connector

Info

Publication number: WO2013178727A1
Application number: PCT/EP2013/061148
Authority: WO
Inventors: Juergen Muehlmichel
Original assignee: Delphi International Operations Luxembourg S.A.R.L.
Priority date: 2012-05-31
Filing date: 2013-05-30
Publication date: 2013-12-05

Abstract

The invention relates to an electrical connector comprising at least one electric cable (3) surrounded by an insulating sheath (5) and a housing (7) arranged on at least a portion of the electric cable. The housing is made of a first material. The electrical connector further comprises a sealing (9) arranged on the electric cable and surrounding the insulating sheath in a sealing manner. The sealing is made of a second material. The housing is molded over the sealing and over at least a portion of the cable to encompass the sealing.

Description

OVER-MOLDED ELECTRICAL CONNECTOR l. Field of the invention

The present invention relates to an electrical connector with an electric cable surrounded by an insulating sheath, a sealing, and a housing, whereby the housing is molded over the sealing and at least a portion of the cable.

2. Technical background

In many applications, it is necessary to mount electrical cables to terminal and/ or connector housings and to seal the connection against moisture and/or dust etc. Conventionally, for the sealing, overmolded electrical connectors are manufactured by molding a housing, e.g. by plastic injection molding, over a cable surrounded by an insulating sheath. Due to the overmolding of the connector housing and the cable a strong bond occurs between housing material and cable material, so that the connection is sufficiently tight against e.g. moisture or the like.

However, in many applications the connection between the cable and the housing surprisingly fails to be sufficiently tight against moisture, dust etc. In particular concerning permanent load, fatigue and creep, the usual sealing properties are often not achieved. It is believed that the reasons lie firstly in different application fields for the electrical connectors with e.g. higher temperatures during manufacturing and/or use, and secondly, in the application of new materials and new material combinations between the cable sheath and the housing. These new conditions lead to a weaker and mostly insufficient chemical and physical connection between the cable sheath and the housing upon overmolding. A typical prior art document dealing with the tightness between different materials is DE 101 27488 Ai. This document discloses a process for producing a plug connection. First, a metal plug pin is surrounded by a sealing made of e.g. silicone by injection molding. Then, the metal plug pin surrounded by the sealing is placed in an injection mold to mold the housing around the metal plug pin with the sealing.

Therefore, it is an object of the present invention to improve the above described situation by providing an improved overmolded electrical connector with an electric cable, an insulating sheath and a housing. In particular, it is an object of the present invention to provide an electrical connector made of new and/or concerning their properties differing materials with good sealing properties. It is a further an object of the present invention to provide an electrical connector which is sealed against moisture or dust etc. for high temperatures during

manufacturing and/or use.

Although electrical connectors are not expensive components, they are mass products and have therefore a considerable influence on the production quality and the production costs of a large number of products. Therefore, it is important to optimize the electrical connectors and the manufacture of such electrical connectors to reduce the manufacturing costs while, at the same time, securing a tight and sufficient fit in a terminal and/or connector housing.

These and other objects, which become apparent upon reading the following description, are solved by an electrical connector according to claim 1.

3. Summary of the invention

According to the invention, an electrical connector comprises at least one electric cable surrounded by an insulating sheath and a housing made of a first material arranged on at least a portion of the electric cable. The electrical connector further comprises a sealing made of a second material arranged on the electric cable surrounding the insulating sheath in a sealing manner. Sealing manner means that there is a satisfactorily gas- and/or fluid-tight connection between the sheath and the housing. The housing is molded over the sealing and over at least a portion of the cable to encompass the sealing. Encompass means that the sealing is completely covered by the injection molded housing. The sealing enables a strong tightness of the electrical connector between the electric cable surrounded by the insulating sheath and the housing whereby this strong tightness is further improved by the overmolding of the housing over the sealing and the cable sheath. The tightness is largely improved in contrast to conventional electrical connectors without overmolded sealings. Further, the sealing and the overmolding enable this strong tightness of the electrical connector even for new and/or concerning their properties differing materials used for the sheath and the housing and for high temperatures used during manufacturing and/or use of the electrical connector.

The electric cable may be e.g. a single wire or a multi-core stranded wire. The housing is made of a first material which may be PE, PP, PUR or the like, a crosslinked material, a reinforced plastic material, a compound material or the like. The sealing is made of a second material which may be a silicone-based material or the like. The second material can also be the same material as the first material, but with amended properties due to e.g. other manufacturing processes, different structures, fiber reinforcements, coatings or the like. Preferably, the sealing and the housing are integrally formed in one step of an over-molding process, which means that the sealing or its material and the material for the housing are subsequently added or injected and then simultaneously molded in one injection molding process. Thereby, the electrical connector may be manufactured faster and more cost- effective than by conventional assembly processes. The sealing and the housing can also be manufactured by a two-component moulding process. Concerning the new materials and new material combinations between the cable sheath and the housing, it was surprisingly found that in particular a combination of a rather soft cable sheath and a rather hard housing leads to a weak and untight chemical and physical connection. To solve this problem, it is preferred that the first and the second materials are adapted to form a tight, chemical bonding during the molding over of the housing. To this end, preferably, the Young's modulus El of the first material for the housing is higher than the Young's modulus E2 of the second material for the sealing. The ratio of Young's modulus E2 / Ei may be at least 10, preferably at least 20, more preferably at least 50, even more preferably at least 75, and most preferably at least 100. The Young's modulus Ei may be in the range between 0.01 to 1.0 kN/mm², more preferably between 0.02 to 0.5 kN/mm², more preferably between 0.03 to o. 2 kN/mm², and most preferably between 0.035 to 0.1 kN/mm². The Young's modulus E2 may be in the range between 0.75 to 250 kN/mm², more preferably between 1.0 to 25 kN/mm², more preferably between 1.5 to 15 kN/mm², and most preferably between 2.0 to 5 kN/mm². The tight, chemical bonding between the sealing, the sheath and the housing may be tight up to 1.5 bar, preferably up to 3 bar and most preferably up to 5 bar. Further in particular, the bonding may be temperature resistant up to 100⁰ C, preferably up to 125⁰ C and most preferably up to 150⁰ C. Preferably, the first and the second materials are adapted to form a bonding which is temperature shock resistant. In particular, the bonding may be temperature shock resistant against about 144 cycles from about - 140⁰ C to about 130⁰ C in about 10 seconds. Further in particular, there is not only a chemical, but also a mechanical bonding between the sheath, the housing and the sealing. Preferably, the sealing is a single wire seal comprising a fastening section to fasten the single wire seal to the sheath and/or to the housing and a tightening section to tighten between the sheath and the housing. The fastening section or the tightening section may be directed to the end of the electric cable depending on external circumferences. To improve the sealing and/or fasting properties, the single wire seal may comprise at least one sealing lip for cooperation with the electric cable (and/or its sheath) and/or at least one sealing projection for cooperation with the housing. The single wire seal may also comprise at least one groove for cooperation with the housing, the electric cable and/or its sheath. To further improve the sealing and/or fasting properties, the sealing lip and/or the sealing projection may extend perpendicular from the longitudinal extension of the cable, and may be provided with a saw- tooth shape. The construction of the mating connection between the single wire seal and the housing and/or the sheath depends inter alia on the materials used, the desired properties of the connection and the operating conditions of the electrical connector. Further preferably, the sealing is at least one O-ring which can be arranged in the first 50 percent of the length of the housing, preferably in the first 35 percent, and even more preferably in the first 10 percent. If several O-rings are used, they can be arranged in contact with each other or spaced apart from each other depending on the desired properties of the electrical connector. Further preferably, the sealing is at least one shrink hose.

4. Description of the preferred embodiments In the following, the invention is described exemplarily with reference to the enclosed figures in which:

Fig. 1 shows a cross section of an electrical connector provided with a single wire seal, shows a cross section of an electrical connector provided with a single wire seal, which is assembled in a reverse direction in contrast to Fig. l, shows a cross section of an electrical connector provided with a shrink hose, shows a cross section of an electrical connector provided with an O-ring near the end of the housing, shows a cross section of an electrical connector provided with an O-ring within the housing, shows a cross section of an electrical connector provided with two O-rings arranged next to each other, and shows a cross section of an electrical connector provided with two O-rings arranged spaced apart from each other.

Figure l shows an electrical connector l, namely a glow plug connector, comprising an electric cable 3 surrounded by an insulating sheath 5 and a housing 7. The housing 7 is arranged at a portion of the electric cable 3 and in particular molded around a part of the length of the cable. The housing 7 comprises in this embodiment a further housing member 71 which is connected to the housing 7 by e.g. pins (not shown). In this embodiment, the housing 7 is plugged into a connector 72 further comprising an inner sheath 73 for a mechanical connection with the housing 7 by means of e.g. ribs 74. The electrical connector 1 further comprises a sealing 9 in form of a single wire seal 95 arranged on the electric cable 3 surrounding the insulating sheath 5 in a sealing manner. The housing 7 is molded over the single wire seal 9 and over a portion of the cable 3 to fully encompass the single wire seal 95.

The single wire seal 95 comprises a fastening section 91 and a tightening section 93, whereby the fastening section 91 is directed to the end of the electric cable 3. The fastening section 91 comprises two sealing lips 92 for a mechanical fixation with the cable3, respectively the cable sheath 5 and three sealing projections 94 for a mechanical fixation with the housing 7. The sealing lips 92 and the sealing projections 94 extend perpendicular from the longitudinal extension of the cable 3. The housing 7 is made of a plastic material as PE, PP, PUR or the like or a crosslinked material, while the single wire seal 95 is made of a silicone- based material or the like. The housing 7 and the single wire seal 95 can alternatively be made from the same base material, but with adjusted properties by e.g. using a different manufacturing process, different additives, as e.g. fiber reinforcements, or the like. The material(s) is/are preferably adapted to form a tight, temperature shock resistant chemical bonding during the molding over of the housing 7. Thereby, the bonding between the housing 7 and the single wire seal 95 is not only a mechanical, but also a chemical bonding.

As Fig. 1, Fig. 2 shows the electrical connector 1 comprising the electric cable 3 surrounded by the insulating sheath 5 and the housing 7. The electrical connector 1 further comprises the single wire seal 95 arranged on the electric cable 3 surrounding the insulating sheath 5 in a sealing manner. Again, the single wire seal 95 comprises a fastening section 91 and a tightening section 93, however, in contrast to Fig. 1, now the tightening section 93 is directed to the end of the electric cable 3.

Whether the fastening section 91 or the tightening section 93 is directed to the end of the electric cable 3 depends on external circumferences.

Also Fig. 3 shows the electrical connector 1 comprising the electric cable 3 surrounded by the insulating sheath 5 and the housing 7. However, in this case, the sealing 9 is a shrink hose 96. The sealing 9 in form of the shrink hose 96 or in form of the single wire seal 95 (see Figs. 1 and 2) extends at the electric cable 3 only for a reduced length relative to the length of the housing 7. A longer sealing 9 would lead to better sealing properties and a stronger and stiffer connection. A shorter sealing 9 would lead to a more flexible and bendable connection, which is easier to assemble. The sealing 9 may also be provided with a constant inner diameter or a tapered diameter, and can be rotation symmetrical or not. It is preferred that the sealing 9 makes up only a small part of the electrical connector 1. In weight percentage, the small part amounts to e.g. only 5 to 30 percent of the overall weight (i.e. the weight of the electrical connector including the weight of the sealing 9), more preferably between 5 and 25 percent and most preferably between 6 and 20 percent.

Figure 4 shows again the electrical connector 1 comprising the electric cable 3 surrounded by the insulating sheath 5 and the housing 7.

However, in this case, the sealing 9 is an O-ring 96. The O-ring 96 is arranged in the first 15 percent of the length of the housing 7. As shown in Fig. 5, the O-ring 96 can also be arranged in the first 35 percent of the length of the housing 7.

Figures 6 and 7 show the sealing 9 in form of two O-rings 96a, 96b. The two O-rings 96a, 96b are arranged in the first 50 percent of the length of the housing 7. The two O-rings 96a, 96b can be arranged next to each other (Fig. 6) or spaced apart (Fig. 7).

Claims

Electrical connector (l) comprising:

- at least one electric cable (3) surrounded by an insulating sheath (5),

- a housing (7) made of a first material arranged on at least a portion of the electric cable (3),

- a sealing (9) made of a second material surrounding the insulating sheath (5) in a sealing manner,

whereby the housing (7) is molded over the sealing (9) and over at least a portion of the cable (3) to fully encompass the sealing (9).

Electrical connector (1) according to claim 1, wherein the sealing (9) is arranged at the electric cable (3) only for a reduced length relative to the length of the housing (7).

Electrical connector (1) according to one of the preceding claims, wherein the sealing (9) and the housing (7) are integrally formed in one step of an over-molding process.

Electrical connector (1) according to one of the preceding claims, wherein the first material is a plastic material as PE, PP, PUR or the like or a cross-linked material.

Electrical connector (1) according to one of the preceding claims, wherein the second material is a silicone based material or the like. 6. Electrical connector (1) according to one of the preceding claims, wherein the Young's modulus El of the first material is higher than the Young's modulus E2 of the second material. lO

Electrical connector (l) according to the preceding claim, wherein the ratio of Young's modulus E2 / Ei is at least 10, preferably at least 20, more preferably at least 50, even more preferably at least 75, and most preferably at least 100.

Electrical connector (1) according to claim 6, wherein El is in the range between 0.01 to 1.0 kN/mm², more preferably between 0.02 to 0.5 kN/mm², more preferably between 0.03 to 0.2 kN/mm², and most preferably between 0.035 to 0.1 kN/mm².

Electrical connector (1) according to claim 6, wherein E2 is in the range between 0.75 to 250 kN/mm², more preferably between 1.0 to 25 kN/mm², more preferably between 1.5 to 15 kN/mm², and most preferably between 2.0 to 5 kN/mm².

Electrical connector (1) according to one of the preceding claims, wherein the first and the second materials are adapted to form a tight, chemical bonding during the molding over of the housing (7).

Electrical connector (1) according to one of the preceding claims, wherein the first and the second materials are adapted to form a bonding which is tight up to 1.5 bar, preferably up to 3 bar and most preferably up to 5 bar.

Electrical connector (1) according to one of the preceding claims, wherein the first and the second materials are adapted to form a bonding which is temperature resistant up to 100⁰ C, preferably up to 125⁰ C and most preferably up to 150⁰ C.

Electrical connector (1) according to one of the preceding claims, wherein the first and the second materials are adapted to form a bonding which is temperature shock resistant. Electrical connector (1) according to one of the preceding claims, wherein the first and the second materials are adapted to form a bonding which is temperature shock resistant against about 144 cycles from about - 140 ⁰ C to about 130⁰ C in about 10 seconds.

Electrical connector (1) according to one of the preceding claims, wherein not only a chemical, but also a mechanical bonding between the housing (7) and the sealing (9) exists.

Electrical connector (1) according to one of the preceding claims, wherein the sealing (9) is at least one single wire seal (95).

Electrical connector (1) according to claim 16, wherein single wire seal (95) comprises a fastening section (91) and a tightening section (93), whereby the fastening section (91) is directed to the free end of the electric cable (3).

Electrical connector (1) according to claim 16, wherein single wire seal (95) comprises a fastening section (91) and a tightening section (93), whereby the tightening section (93) is directed to the end of the electric cable (3).

Electrical connector (1) according to one of the preceding claims 16 to 18, wherein the single wire seal (95) comprises at least one sealing lip (92) for cooperation with the electric cable (3).

Electrical connector (1) according to one of the preceding claims 16 to 19, wherein the single wire seal (95) comprises at least one sealing projection (94) for cooperation with the housing (7).

Electrical connector (1) according to claim 19 or 20, wherein the sealing lip (92) and/or the sealing projection (94) extends perpendicular from the longitudinal extension of the cable (3).

22. Electrical connector (l) according to claim 19 or 20, wherein the sealing lip (92) and/or the sealing projection (94) has a sawtooth shape.

23. Electrical connector (1) according to one of the preceding claims 1 to 15, wherein the sealing (9) is at least one O-ring (96).

24. Electrical connector (1) according to claim 23, wherein the at least one O-ring (96) is arranged in the first 50 percent of the length of the housing (7), preferably in the first 35 percent, and even more preferably in the first 15 percent.

25. Electrical connector (1) according to claim 23 with two O-rings (96) arranged in contact with each other or spaced apart from each other.

26. Electrical connector (1) according to one of the preceding claims 1 to 15, wherein the sealing (9) is at least one shrink hose (97).

27. Electrical connector (1) according to one of the preceding claims, wherein the electrical connector is a glow plug connector