WO2019111219A1

WO2019111219A1 - Multipolar electric connector and method of manufacture

Info

Publication number: WO2019111219A1
Application number: PCT/IB2018/059750
Authority: WO
Inventors: Gustavo Francisco LOZANO MANNERSTRALLE
Original assignee: Ream Srl
Priority date: 2017-12-07
Filing date: 2018-12-07
Publication date: 2019-06-13

Abstract

A multipolar electric connector (1) for liquid-tight connection of at least one multipolar cable (M) with an electromechanical device, wherein the connection comprises a plurality of power conductors (C) in the cable (M) and a ground conductor (G), having respective terminations. The connector (1) comprises a body (2) having a longitudinal axis (X) for receiving the end (E) of the multipolar cable (M), a plurality of electrical terminals (3) embedded in the body (2) and a substantially annular grounding element with an outer edge (9) and an inner edge (10), which is partially embedded in the body (2). The element (6) has at least one appendage (7) with a tab (11) projecting out of the inner edge (1 0). A female lug (8) is further provided, whose shape allows it to be mounted to the termination of the ground conductor (G) by crimping, for plug-in coupling of the appendage (7). The connector (1) comprises a support spacing member (13), which is adapted to keep the terminals (3) spaced apart from and substantially parallel to each other, and is designed to be housed in the annular element (6) and be coupled thereto by means of longitudinal projections (14) adapted to engage in the edge (10) of the element (6), to increase the tensile strength of the conductors (C, G) relative to the body (2).

Description

MULTIPOLAR ELECTRIC CONNECTOR AND METHOD OF MANUFACTURE

Field of The Invention

[0001] The present invention is generally directed to the field of electric elements and particularly relates to a multipolar electric connector for liquid- tight connection.

[0002] The invention further relates to a method of manufacturing the aforementioned multipolar electric connector.

Background art

[0003] In the field of electrical devices, multipolar connectors have been long known for liquid-tight connection of a multipolar cable with an electromechanical device to be powered.

[0004] These connectors generally provide electric connection between the power conductors of the multipolar cable and the corresponding electric contacts of the electromechanical device.

[0005] A multipolar cable with a ground conductor is used to ensure electric ground continuity between the electromechanical device and the power source upstream from the cable. Such ground connector is welded to an additional element made of a conductive metal material, which is electrically connected to the casing and the metal parts of the device.

[0006] Nevertheless, electrical continuity may be inadequate under particular conditions of installation of the electromechanical device, e.g. when the latter is submerged in a liquid or operates in rugged environments having a high atmospheric pressure.

[0007] In an attempt to at least partially obviate these drawbacks, tight connectors have been developed, which can improve electrical grounding continuity.

[0008] US5490789 discloses a multipolar connector for tight electrical connection comprising a body made of an insulating material with a plurality of electric terminals connected to a respective power conductor of the multipolar cable. [0009] In addition, the connector comprises an annular grounding element, which is at least partially embedded in the body made of insulating material and has a peripheral appendage connected by welding to the ground conductor.

[0010] PD2015U000013 discloses a multipolar connector comprising an injection-molded body made of an insulating material and an annular grounding element that is partially embedded in the body and is connected by welding to the ground conductor of the multipolar cable.

[0011] The grounding element is adapted to ensure electrical continuity between the ground conductor and the casing of the device to be powered by contact with a metal element interposed between the annular element and the electromechanical device.

[0012] A first drawback of these arrangements is that the welding area with the grounding element does not cover the entire section of the ground conductor, which affects proper grounding and possibly causes overheating of the ground wire in case of failure.

[0013] Furthermore, welding requires the copper termination of the ground conductor to project out of the molded body. This configuration affects the overall tightness of the connector.

[0014] Due to this drawback, the section of the ground conductor must be increased to prevent overheating thereof, and this will increase the manufacturing costs for the multipolar connector.

[0015] Another drawback of these arrangements is that welding increases the risk of oxidation between the welding material, the metal material of the annular element and the copper in the ground conductor.

[0016] An additional drawback of this arrangement is that, during injection of the insulating material, the electric terminals are not continuously supported in the body of the connector.

[0017] Another drawback is that the electric terminals must be crimped with their respective power conductors one at a time, which increases the overall assembly time. Technical Problem

[0018] In the light of the prior art, the technical problem addressed by the present invention consists in providing a multipolar electric connector for liquid- tight connection of a multipolar cable with an electromechanical device, that can ensure uniform and time-stable electrical coupling between the cable conductors and the elements of the connector and the electromechanical device.

Disclosure of the invention

[0019] The object of the present invention is to solve the aforementioned problem by providing a multipolar electric connector for tight connection of a multipolar cable and an electromechanical device and a method of manufacture that are highly efficient and relatively cost-effective.

[0020] A particular object of the present invention is to provide a multipolar electric connector as described above that can ensure uniform and time-stable electrical coupling between the power and ground conductors and the elements of the connector and the electromechanical device.

[0021] A further object of the present invention is to provide a multipolar electric connector as described hereinbefore that can be used in any operating condition.

[0022] Another object of the present invention is to provide a multipolar electric connector as described hereinbefore that prevents the risk of oxidation of the electrical grounding connection.

[0023] Yet another object of the present invention is to provide a multipolar electric connector as described hereinbefore, whose fabrication involves the use of inexpensive and easily available parts.

[0024] Another object of the present invention is to provide a multipolar connector as described hereinbefore, that ensure long-lasting liquid tightness.

[0025] A further object of the present invention is to provide a multipolar connector as described hereinbefore that can simplify crimping of the terminals with their respective power conductors.

[0026] Another object of the present invention is to provide a method of manufacturing a multipolar electric connector as described hereinbefore, that can avoid displacement of the electric terminals during injection of the insulating material.

[0027] These and other objects, as more clearly explained hereinafter, are fulfilled by a multipolar electric connector for liquid-tight connection of at least one multipolar cable and an electromechanical device, as defined in claim 1 , which includes a plurality of power conductors in the cable and a ground conductor with respective terminations and insulators, which are covered by an outer insulating sheath.

[0028] The connector comprises a body having a longitudinal axis that is designed to receive the end of a multipolar cable, a plurality of electric terminals embedded in the body, each connected to a respective termination of the power conductors and a grounding element at least partially embedded in the body and provided with at least one peripheral appendage.

[0029] In addition, the connector comprises a female pin lug whose shape allows it to be mounted to the termination of the ground conductor by crimping, for plug-in electrical coupling of the ground conductor with the appendage of the grounding element.

[0030] In a peculiar aspect of the invention, the connector comprises a support spacing member which is adapted to keep the terminals spaced apart from and substantially parallel to each other. Furthermore, the support spacing member is designed to be housed in the annular grounding element and to be coupled thereto by means of a plurality of longitudinal projections adapted to engage in the inner edge of the annular grounding element to increase the tensile strength of the power and ground conductors relative to the body (2).

[0031] The female pin lug allows uniform and time-stable coupling of the ground conductor of the cable and the grounding element of the connector with no welding spots, thereby reducing the risk of oxidation.

[0032] As defined in claim 10, the invention also relates to a method of manufacturing a multipolar electric connector for liquid-tight connection of a multipolar cable with an electromechanical device. [0033] Advantageous embodiments of the invention are obtained in accordance with the dependent claims.

Brief Description of The Drawings

[0034] Further features and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a multipolar electric connector, which is described as a non limiting example with the help of the annexed drawings, in which:

FIG. 1 is a perspective view of a multipolar electric connector according to a first embodiment of the invention;

FIG. 2 is an exploded perspective view of the connector of Fig. 1 ;

FIG. 3 is a perspective view of a detail of the multipolar electric connector of Fig. 1 ;

FIG. 4 is a front view of the connector of Fig. 1 ;

FIG. 5 is a broken-away top view of the multipolar electric connector of

Fig. 1 ;

FIG. 6 is a broken-away side view of the multipolar electric connector of

Fig. 1 ;

FIG. 7 is a perspective view of a detail of the multipolar electric connector of Fig. 1 ;

FIG. 8 is a perspective view of the multipolar electric connector according to a second embodiment;

FIG. 9 is an exploded perspective view of the connector of Fig. 8;

FIG. 10 is a perspective view of a detail of the multipolar electric connector of Fig. 8.

Detailed description of a preferred exemplary embodiment

[0035] Particularly referring to the figures, there is shown a multipolar electric connector 1 for liquid-tight, preferably pressurized connection of at least one multipolar cable M with an electromechanical device, not shown.

[0036] The electromechanical device may be a submerged pump or a device that needs to be isolated from liquids or liquid-tight to be used under high- pressure environmental conditions. [0037] As shown in FIG. 2, a plurality of power conductors C in the cable and a ground conductor G are provided, which have respective terminations and insulators and are covered by one or more outer insulating sheaths S.

[0038] Preferably, as shown in the figures, the ground conductor G may be also included in the multipolar cable M or alternatively it may be separately provided separately in a free-hanging cable.

[0039] In addition, the cable M may comprise flexible single-pole power conductors C-i, C2, C3 and a ground conductor G connected to an upstream three-phase power system, not shown.

[0040] The multipolar cable M may comprise a non-reinforced outer sheath S made of a low-water absorption crosslinked rubber and have a first outer sheath S' for covering the power conductors C and a second outer sheath, not shown, for the ground conductor G, that can be separate from the first sheath S'.

[0041] Alternatively, a single outer sheath S may be provided for simultaneously covering the ground conductor G and the power conductors C, which contains filler material adapted to define a multipolar cable M having a circular cross section.

[0042] As shown in FIGS. 1 and 2, the multipolar electric connector M comprises a body 2 having a longitudinal axis X, which is designed to receive the end W of the multipolar cable M and a plurality of electric terminals 3 embedded in body 2, each connected to a respective termination of the power conductors C-i, C2, C3.

[0043] Namely, the body 2 may comprise a first end portion to 4 which is adapted to interact with the electromechanical device and is designed to receive the electric terminals 3 and a second end portion 4" in which the end E of the multipolar cable M is embedded.

[0044] Conveniently, the body 2 may be formed by injection molding in a single-cavity mold, with an insulating material that can ensure electrical insulation with a degree of protection greater than IP67, preferably a degree of protection rated IP68. [0045] The insulating material injected into the mold may be selected from the group comprising epoxy resins, thermoplastic rubbers, thermoplastic crosslinked polymers, insulating materials having the same electrical and mechanical properties as the outer sheath S of the multipolar cable M, and technically equivalent materials, as long as they are suitable to be injected into a mold.

[0046] Advantageously, the first portion 4' of the body 2 may comprise a plurality of passages 5, allowing connection between the electric terminals 3A, 3B, 3C and the corresponding electric contacts of electromechanical device to be powered, not shown.

[0047] As is known per se, the multipolar electric connector 1 may comprise female electric terminals 3 adapted to interact with corresponding male electric contacts of the electromechanical device.

[0048] Namely, the electric terminals 3A, 3B, 3C embedded in the first portion 4' of the body 2 are as many as the power conductors C-i , C2, C3 of the multipolar cable M and may have a substantially tubular shape to be coupled to their terminations by crimping.

[0049] As shown in FIGS. 2, 7, 9 and 10, the female electric terminals 3A, 3B, 3C may be of non-isolated, plug-in type and comprise a first section 3 for receiving the termination of the power conductors C and a second enlarged section 3" for receiving the plug-in male contacts of the electromechanical device.

[0050] As shown in FIGS. 1 to 3, the multipolar electric connector 1 comprises a grounding element 6 made of a conductive metal material at least partially embedded in the body 2 and having at least one peripheral appendage 7.

[0051] As is known per se, the multipolar electric connector 1 may interact with the electromechanical device by covering the grounding element 6 with a matingly shaped metal element having a flange connected to the casing and to the metal parts of the device.

[0052] To facilitate this overlapped arrangement, the first portion 4' of the body 2 may comprise an intermediate region 4"' whose outside diameter is greater than that of the first 4’ and second 4” portions.

[0053] In a first embodiment, as shown in FIGS. 1 to 7, the intermediate region 4"' may comprise a completely cylindrical shape.

[0054] In a second embodiment, as shown in FIGS. 8 to 10, the intermediate region 4"' may comprise a partially cylindrical shape, as well as a specially shaped region 4"" having a substantially polygonal cross- section.

[0055] The connector comprises a female pin lug 8 whose shape allows it to be mounted to the termination of the ground conductor G by crimping, for plug in electrical coupling of the ground conductor G with the appendage 7 of the grounding element 6.

[0056] In a preferred embodiment of the invention, the body 2 of the connector 1 may have a substantially cylindrical shape and the grounding element 6 may be substantially annular, with an outer edge 9 and an inner edge 10.

[0057] In the first embodiment, the outer edge 9 and the inner edge 10 of the annular grounding element 6 may have a substantially circular shape, as shown in FIG. 7.

[0058] In the second embodiment, the outer edge 9 may comprise a polygonal shape substantially coinciding with that of the specially shaped region 4"" and a substantially rectangular inner edge 10, as shown in FIG. 10.

[0059] The peripheral appendage 7 may comprise at least one tab 1 1 projecting out of the inner edge 10 and obtained by appropriately bending toward the second portion 4 of the body 2.

[0060] The grounding element 6 may be partially embedded in the intermediate region 4"' of the body 2 and be interposed between the first 4 and the second 4” portions, for the outer edge 9 to facilitate grounding of the electromechanical device.

[0061] In addition, the tab 1 1 may longitudinally extend from the annular grounding element 6, and the female pin lug 8 and the tab 1 1 may be entirely embedded in the body 2 of the multipolar electric connector 1 .

[0062] Preferably, as shown in FIGS. 2 and 7, the annular grounding element 6 may comprise a pair of parallel tabs 1 1 embedded in the second portion 4" of the body 2.

[0063] Advantageously, the female pin lug 8 may be a naked faston terminal, whose shape allows connection to the tab 1 1 or tabs 1 1 without welding.

[0064] As is known per se, the faston terminal 8 may comprise first and second pairs of wings, not shown, for retaining the insulator and termination of the ground conductor G respectively.

[0065] As shown in FIGS. 2 to 6, the faston terminal 8 may comprise a third pair of wings 12 allowing plug-in electrical coupling with the pair of projecting wings 1 1 along their entire extent.

[0066] By this arrangement, the entire surface of the termination of the ground wire G may contact the tabs 1 1 of the grounding element 6, thereby ensuring electrical coupling with reduced contact resistance. Alternatively, the faston terminal 8 may provide smooth, cog-operated or pull-resistant plug-in, without departure from the scope of the present invention.

[0067] In a peculiar aspect of the invention, the electric connector 1 comprises a support spacing member 13 which is adapted to keep the terminals 3A,3B, 3c spaced apart from and substantially parallel to each other.

[0068] As shown in FIG. 3, the support spacing member 13 is housed in the annular grounding element 6 and is coupled thereto by means of a plurality of longitudinal projections 14 adapted to engage in the inner edge 10 of the annular grounding element 6.

[0069] In addition, each of the longitudinal projections 14 may comprise retaining pins 15, which are designed for snap-fit engagement in the inner edge 10 of the annular grounding element 6 to increase the tensile strength of the power conductors C and the ground conductor G relative to the body 2.

[0070] The support member 13 may have a substantially disk-like shape with a plurality of angularly offset, equally spaced openings 16A, 16B, 16C for receiving the electric terminals 3A, 3B, 3C and form therewith a first assembly 17, as shown in FIGS. 7 and 10.

[0071] By this arrangement, the support member 13 may ensure alignment and equal distance between the electric terminals 3 during injection of the insulating material into a mold to form the body 2.

[0072] Furthermore, the support spacing member 13 will allow simultaneous crimping of the electric terminals 3A, 3B, 3C using a crimping machine, thereby reducing the times for manufacture of the connector 1 .

[0073] Advantageously, the support member 13 and the first assembly 17 may ensure a high tensile strength when pulling or tugging at the power conductors C and the ground conductor G from the body 2 or when uncoupling the connector 1 from the electromechanical device.

[0074] Once the connector 1 has been formed, the support member 13 may act as a "parachute" with respect to the insulating material of the body 2, thereby preventing the multipolar cable M from slipping out of the body 2, the power conductors C from slipping out of their respective electric terminals 3 and the ground conductor G from slipping out of the lugs 8.

[0075] Experimentally, in both first and second embodiments, the connector 1 has been found to have a tensile strength that ranges from 50 kg to 150 kg, preferably 130kg and a tightness higher than or equal to 15 bar. These values were derived using duly certified equipment.

[0076] As shown in FIG. 4, the openings 16A, 16B, 16C may be angularly offset by a predetermined angle a, thereby ensuring that the electric terminals 3A, 3B, 3C will have such an arrangement as to interact with most of the male electric contacts of the commercially available electromechanical devices.

[0077] It will be understood that the electric connector 1 as described above ensures uniform and time-stable electrical coupling between the ground conductor G and the grounding element 6 and between the plurality of electric terminals 3 of the cable M and the electric contacts of the electromechanical device.

[0078] In a further aspect, the invention relates to a method of manufacturing a multipolar electric connector 1 for liquid-tight connection of a multipolar cable M with an electromechanical device.

[0079] The method comprises a step of a) providing an annular grounding element 6 having an inner edge 10 with a projecting appendage 7 in the form of a tab 1 1 and a step of b) providing a plurality of electric terminals 3 and a support spacing member 13.

[0080] The support member 13 comprises a plurality of openings 16A, 16B, 16C for receiving the electric terminals 3A, 3B, 3C and a plurality of longitudinal projections 14 adapted to fit into the inner edge 10 of the grounding element 6.

[0081] The method further comprises a step of c) coupling each electric terminal 3a, 3B, 3C with the support member 13 to obtain a first assembly 17 and a step of d) coupling of the electric terminals 3A, 3B, 3C with respective terminations of power conductors C-i , C2, C3 of the multipolar cable M by single crimping, to thereby obtain a second assembly 18, as shown in FIG. 3.

[0082] As discussed hereinbefore, such crimping may be carried out in a single step by means of a crimping machine for reducing the time for manufacture of the second assembly 18 and hence the connector 1 .

[0083] Advantageously, the method comprises a step of e) introducing the second assembly 18 into a mold and a step of f) injecting insulating material into the mold to form a body 2 having a longitudinal axis X.

[0084] Upstream from the step of f) injecting, a step of g) providing a female pin lug 8 and a step of h) coupling the female pun lug 8 on the termination of the grounding terminal G by crimping are provided, for electric weldless plug in coupling between the ground conductor G and the projecting tab 1 1 and for incorporation of the female pin lug 8 in the second end portion 4”.

[0085] Thus, the method of manufacturing the multipolar electric connector 1 of the invention allows uniform plug-in engagement of the ground conductor G with the female pin lug 8 along the entire extension of the at least one tab 1 1 of the grounding element 6, thereby affording simple manufacture and time- stable electrical coupling.

[0086] Furthermore, the manufacture of the connector 1 with the inventive method prevents the electric terminals 3 from changing their position during the step of f) injecting the insulating material due to the presence of the support member 13. Industrial Applicability

[0087] The present invention may find application in industry, because it can be produced on an industrial scale in factories operating in the field of electric coupling devices.

Claims

1 . A multipolar electric connector (1 ) for liquid-tight connection of at least one multipolar cable (M) with an electromechanical device, wherein the connection comprises a plurality of power conductors (C) in the cable (M) and a ground conductor (G), having respective terminations and insulators, said connector (1 ) comprising:

- a substantially cylindrical body (2) having a longitudinal axis (X) for receiving the end (E) of the multipolar cable (M);

- a plurality of electric terminals (3) embedded in said body (2), each connected to a respective termination of the power conductors (C);

- a grounding element (6) at least partially embedded in said body (2) and having at least one peripheral appendage (7), said grounding element (6) being substantially annular, with an outer edge (9) and an inner edge (10) and said at least one appendage (7) being a tab (1 1 ) projecting out of said inner edge (10);

- a female pin lug (8) whose shape allows it to be mounted to the termination of the ground conductor (G) by crimping, for plug-in electrical coupling of the ground conductor (G) with said appendage (7);

characterized in that it comprises a support spacing member (13) for keeping said electric terminals (3) spaced apart from and substantially parallel to each other, said support spacing member (13) being designed to be housed in said annular grounding element (6) and to be coupled thereto by means of a plurality of longitudinal projections (14) adapted to engage in the inner edge (10) of said annular grounding element (6) to increase the tensile strength of the power conductors (C) and the ground conductor (G) relative to said body (2).

2. Connector as claimed in claim 1 , characterized in that said at least one tab (1 1 ) extends longitudinally from said annular grounding element (6), said female pin lug (8) and said at least one tab (1 1 ) being entirely embedded in said body (2).

3. Connector as claimed in claim 2, characterized in that said body (2) comprises a first end portion (4') designed to receive said terminals (3) and a second portion (4”) in which the end (E) of the multipolar cable (M) and said at least one tab (1 1 ) are embedded.

4. Connector as claimed in claim 3, characterized in that said annular grounding element (6) is interposed and embedded between said first (4') and said (4") second portions.

5. Connector as claimed in claim 3, characterized in that said first portion (4') comprises an intermediate region (4"') whose outside diameter is greater than that of the first (4’) and second (4”) portions.

6. Connector as claimed in claim 1 , characterized in that said female pin lug (8) is a naked faston terminal whose shape allows it to be coupled to said at least one tab (1 1 ) without welding.

7. Connector as claimed in claim 3, characterized in that said electric terminals (3) have a substantially tubular shape and are adapted to be coupled to the terminations of the power conductors (C) by crimping, said support element (13) having a substantially disk-like shape with a plurality of angularly offset, equally spaced openings (16) for receiving said electric terminals (3).

8. Connector as claimed in claim 1 , characterized in that said body (2) is formed by injection molding with an insulating material that can ensure electrical insulation with a degree of protection greater than IP67, preferably rated IP68.

9. Connector as claimed in claim 1 , characterized in that it comprises a tensile strength that ranges from 50 kg to 150 kg, preferably 130 kg, and a tightness higher than or equal to 15 bar.

10. A method of manufacturing a multipolar electric connector (1 ) for liquid-tight connection of at least one multipolar cable (M) with an electromechanical device, wherein there are provided a plurality of power conductors (C) in the cable and one ground conductor (G), with respective terminations and insulators, which are covered by an outer insulating sheath (S), said method comprising the steps of:

a) providing an annular grounding element (6) having an inner edge (10) with a projecting appendage 7 in the form of a tab (1 1 );

b) providing a plurality of electric terminals (3A, 3B, 3C) and a support spacing member (13) having a plurality of openings (16A, 16B, 16C) for receiving said electric terminals (3A, 3B, 3C);

c) coupling each electric terminal (3A, 3B, 3C) with the support member

(13) to obtain a first assembly (17);

d) coupling said electric terminals (3A, 3B, 3C) with respective terminations of the power conductors (C1 , C2, C3) of the multipolar cable (M) using a single crimping to thereby obtain a second assembly (18);

e) introducing said second assembly (18) into a mold;

f) injecting insulating material into the mold to form a body (2) having a longitudinal axis (X), said body (2) having a first end portion (4') designed to receive said electric terminals (3A, 3B, 3C) and a second end portion (4”), in which the end (E) of the multipolar cable (M) is at least partially embedded; wherein upstream from said f) injecting step, a step of g) providing a female pin lug (8) and a step of h) coupling said female pun lug (8) on the termination of the grounding terminal (G) by crimping are provided, for electric weldless plug-in coupling between the ground conductor (G) and said at least one projecting tab (1 1 ) and for incorporation of said female pin lug (8) in said second end portion (4”);

characterized in that said support spacing member (13) is designed to be housed in said annular grounding element (6) and to be coupled thereto by means of a plurality of longitudinal projections (14) adapted to engage in the inner edge (10) of said annular grounding element (6) in said step of c) introducing, to increase the tensile strength of the power conductors (C) and the ground conductor (G) relative to said body (2).