Shielded cable connector and method for making an electrical connection therewith

Description

[0001] Electrical connectors as disclosed herein are used with shielded cables such as those used in high power transmission applications and, more specifically relate to electrical connectors that are specially configured to provide a highly reliable cable shield connection for grounding purposes in a manner that is resistant to vibration and that avoids unwanted contact of the cable shield with the cable main conductor.

[0002] The use of electrical connectors configured to provide a connection between the shield of a shielded cable and a connector housing for grounding purposes is known in the art and is disclosed in US 6019615, CN 205828685 and EP 0986135.

[0003] EP 0986135 discloses a cable shield connector comprising an assembly having an inner ferrule disposed over an outer insulating sleeve of a cable, and an outer ferrule disposed concentrically around the inner ferrule. A portion of a cable shield of the cable is interposed between and in direct contact with both ferrules, and extends around a terminal end of an outer insulating sleeve of the cable and over an outer surface of the inner ferrule. The outer ferrule has an inner annular flange at one end that effectively covers the terminal end of the outer insulating sleeve. The other end is flared outwardly and comprises spring-type legs which engage a housing when the assembly is disposed in a cavity of the housing.

[0004] The need to provide an effective and robust grounding of shielded cables is especially important in high-power applications such as in the hybrid and electrical Industrial and Commercial Transportation (ICT) industry that call for high levels of EMI protection and resistance to high vibration for functional and safety reasons. Such conventional electrical connectors currently used in these demanding applications often utilize non-conductive materials such as plastic for the connector housing and sheet metal shielding components for EMI protection. During the course of use, such conventional connectors comprising such sheet metal components often fail under conditions of high vibration, and thus do not provide a grounding construction that adequately addresses the need to provide reliable EMI protection as called for in such end-use applications.

[0005] The problem to be solved is providing electrical connectors as claimed in claim 1 that are constructed in a manner that provides an effective and robust degree of shielded cable grounding under conditions of high vibration, to thereby address the need not adequately met by conventional connectors to provide a high degree of EMI protection and resistance to vibration to extend the effective service life of such connectors while improving the degree of reliable power transmission in such end-use applications.

[0006] The problem is solved by a cable shield connector as claimed in claim 1 and a method for providing an electrical connection with a cable shield connector as claimed in claim 2.

[0007] Shield grounding electrical connectors as disclosed herein provide a grounding electrical connection with a cable that is robust and resistant to vibration by interposing the cable shield portion of the cable between inner and outer ferrules of the connector thereby forming an assembly. The assembly is then inserted into a connector housing inner cavity whereby a canted coil spring provides a resilient and robust grounding electrical compressed contact between the opposed circumferential outside surface of the assembly and housing inner cavity. As the canted coil spring is fixed axially relative to the housing inner cavity, such permits repeated insertion and removal without compromising the ability to provide the desired robust grounding electrical connection therebetween in a manner that is resistant to vibration.

[0008] The invention will now be described by way of example with reference to the accompanying figures, of which: FIG. 1A is a perspective view of an example inner and outer ferrule assembly as used with shield grounding electrical connectors as disclosed herein. FIG. 1B is a perspective view of an inner ferrule of the inner and outer ferrule assembly of FIG. 1A; FIG. 1C is a perspective view of an outer ferrule of the inner and outer ferrule assembly of FIG. 1A; FIG. 2 is a cross-sectional side view of a shield grounding electrical connector that is not according to the invention but is provided for illustration purposes only; FIG. 3 is a perspective cut-out sectional view of the shield grounding connector of FIG. 2. FIG. 4 is a cross-sectional side view of an example shield grounding electrical connector as disclosed herein; and FIG. 5 is a cross-sectional side view of another shield grounding electrical connector that is not according to the invention but is provided for illustration purposes only.

[0009] Arrangements and an embodiment of shield grounding electrical connectors as disclosed herein will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. Shield grounding electrical connectors as disclosed herein may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein; rather, this embodiment is provided so that the disclosure will be thorough and complete, and will fully convey the concept of shield grounding electrical connectors to those skilled in the art.

[0010] Shield grounding electrical connectors as disclosed herein are generally configured comprising an inner ferrule, and an outer ferrule that are each specially configured having sections that cooperate with one another to accommodate shielding from a shielded cable therebetween and that are crimped together to fixedly capture the shielding therebetween, thereby forming an inner and outer ferrule assembly. Each of the inner and outer ferrules are also configured to ensure that the shielding interposed and captured therebetween does not contact the power cable main conductor. Further, the outer ferrule is specially configured to connect with a housing construction for purposes of providing a grounded electrical connection of the cable shield with the housing in manner that is robust and resistant to high levels of vibration, thereby providing a high level of reliable EMI protection as called for by certain end-use applications such as power transmission in the hybrid and electrical ICT industry.

[0011] FIG. 1A illustrates an inner and outer ferrule assembly 10 as used with shield grounding electrical connectors as disclosed herein. The assembly 10 comprises an inner ferrule 12 that is coupled together with an outer ferrule 14, wherein a shielded cable 16 is disposed through an inside diameter of both the inner and outer ferrules 12 and 14, and a shield portion 18 of the cable is interposed between and captured by opposed surfaces of the inner and outer ferrules 12 and 14. A terminal insulator 20 is shown interfaced and / or otherwise engaged with an axial end 22 of the inner ferrule 12 opposite the outer ferrule 14.

[0012] Referring to FIG. 1B, the inner ferrule 12 is shown in an example having an annular configuration with a first section or neck 24 that extends axially a distance from an axial end 26 of the inner ferrule to a shoulder section 28 that extends radially outwardly from the neck 24 and in an axial direction towards end 22. In an example, the shoulder section 28 may have an angle of departure as measured along an axis running axially parallel to the neck of less than about 90 degrees, from about 30 to 85 degrees, and from about 45 to 70 degrees. In an example, the neck section 24 is sized having an inside diameter that fits over the shielded cable, and in an example that fits over a section of the shielded cable after an outer insulating sleeve of the cable has been removed to expose the shield portion of the cable, and after the shield portion has been moved radially outward to expose a cable inner insulating sleeve. In an example, the neck section has a constant diameter. The shoulder section 28 extends radially outwardly to a second or skirt section 30 that extends axially a distance therefrom to the axial end 22. In an example, the skirt section may be configured to cooperate with an end section of a connector terminal 20 and the like to facilitate an attachment therewith. In an example, the skirt section 30 has a constant diameter.

[0013] In an example, the inner ferrule 12 is formed from an electrically conductive material that has a desired degree of structural rigidity while also being capable of being deformed in a crimping operation to join the inner and outer ferrules together and trap the shield portion of the cable therebetween. Example electrically conductive materials useful for forming the inner ferrule include metals and metal alloys. In an example, the inner ferrule is made from copper or copper alloy. In an example, the inner ferrule is a one-piece construction that may be formed having the desired configuration by conventional molding or stamping techniques.

[0014] FIG. 1C illustrates the outer ferrule 14 configured having an annular configuration with a first section or neck 32 that extends axially a distance from an axial end 34. In an example, the axial end 34 is flared radially outwardly a distance for purposes of placement adj acent the inner ferrule shoulder section 28 when the inner and outer ferrules are joined together. In an example, the neck section 32 has an inside diameter that is sized to fit over the inner ferrule neck section 24. In an example, the inner ferrule neck section outside diameter and the outer ferrule neck section inside diameter are sized to accommodate placement of the outer ferrule neck section over the inner ferrule neck section after the cable shield portion has been disposed over the inner ferrule neck section. Thereafter, the two neck sections of the inner and outer ferrule may be attached together by a crimping process to mechanically trap the cable shield portion therebetween, thereby forming the inner and outer ferrule assembly.

[0015] In an example, the axial end 34 may have an outward angle of departure as measured from an axis running axially through the outer ferrule 14 of greater than about 2 degrees, and from about 5 to 60 degrees. In an example, it is desired that the axial end 34 has an angle of departure that is less than that of the inner ferrule shoulder section 28 for purposes of tightly capturing the shield portion of the cable therebetween. The outer ferrule neck section 32 extends axially a distance from the axial end 34 to a shoulder section 36 that extends radially outwardly therefrom to a second or skirt section 38 that extends axially from the shoulder section to an axial end 40 of the outer ferrule. In an example, the shoulder section 36 may have an angle of departure as measured along an axis running axially through the outer ferrule of less than about 90 degrees, from about 10 to 80 degrees, and from about 25 to 60 degrees. Functionally, it is desired that the shoulder section 36 has an angle of departure that facilitates passage of the outer ferrule into a housing inner cavity and engagement and passage along an interconnection element without causing binding of the inner and outer ferrule assembly within the inner cavity as will be described below. In an example, it is desired that the inner ferrule and outer ferrule neck sections extend an axial length that is similar to provide similar cable shield portion surface contact areas therebetween. The outer ferrule skirt section 38 is configured having an outer diameter that is sized to accommodate axial movement within a housing and make an electrical grounding connection therewith. The outer ferrule skirt section 38 has an inside diameter that is sized to accommodate placement of the shielded cable therethrough. The outer ferrule may be made from the same types of electrically conductive materials and may be formed as described above for the inner ferrule.

[0016] FIG. 2 illustrates an example shield grounding electrical connector 100 as disclosed herein comprising the inner and outer ferrule assembly 10 that includes the inner and outer ferrules 12 and 14, as discussed above and illustrated in FIGS. 1A to 1C. The inner and outer ferrule assembly 10 is disposed within a rigid housing 102 to thereby form the connector 100. In an example, the housing 102 is a rigid structure that is formed from an electrically conductive material for purposes of providing a desired electrical grounding connection with the inner and outer ferrule assembly 10. In an example, the housing is formed from aluminum. The housing includes an inner cavity 104 that is sized to accommodate the inner and outer ferrule assembly 10 therein, and in an example the inner cavity has a cylindrical shape.

[0017] A sleeve or spacer 106 is disposed circumferentially around an inner insulating sleeve 108 of the shielded cable 16 after a portion of the cable outer insulating sleeve 110 is removed to expose a section of the cable shield 18 that is moved radially outwardly from the cable. In an example, the sleeve 106 is formed from an electrically nonconductive material and has an outside diameter sized to enable fitment of the inner ferrule neck section 24 thereover. The cable shield 18 extends axially from an end of the outer insulating sleeve 110 and extends radially outwardly from the cable inner insulating sleeve 108 where it then extends axially between and is captured by the opposed inner and outer ferrule neck sections 24 and 32.

[0018] In an example, preparation of the cable and attachment of the inner and outer ferrules to capture the cable shield portion therebetween to thereby form the inner and outer ferrule assembly is conducted prior to inserting the assembly into the housing 102, thereby forming the connector 100. As illustrated, it is desired that a portion of the cable shield portion extends along the inner ferrule, e.g., along the shoulder section 28 beyond the outer ferrule flared end 34, for purposes of providing a visual indication that the cable shield portion is adequately captured by the inner and outer ferrules. As best shown in FIG. 2, a feature of the inner ferrule shoulder section 28 and its radially outward directed configuration is that it operates to direct the cable shield portion 18 radially outwardly away from the cable so as to mitigate and avoid the possibility of the shield making contact with a main conductor 112 of the shielded cable 16, to thereby prevent an undesired short circuit.

[0019] The inner ferrule skirt section 30 is disposed within the housing inner cavity 104 and the terminal insulator 20 is connected thereto through the inner ferrule axial end 22. In an example, the terminal insulator includes an axial end 114 that is configured to fit within an inside diameter of the inner ferrule skirt section 30. A portion of the shielded cable with the shield portion removed therefrom and including the inner insulating sleeve 108 extends axially from the sleeve 106 and into and through an inside diameter 116 of the terminal insulator 20. In an example, the terminal insulator 20 may be formed from an electrically nonconductive material.

[0020] The outer ferrule 14 extends from its connection with the inner ferrule 12 along the overlapping respective neck sections 24 and 32 in an opposite axial direction from the inner ferrule within the housing inner cavity 104. In an example, a grounding electrical connection is made between the inner and outer ferrule assembly 10 and housing 102 through the use of an interconnecting element 118, wherein the interconnecting element 118 is interposed between and in electrical contact with both the inner and outer ferrule assembly 10 and the housing 102. In an example, the interconnecting element is formed from an electrically conductive material and extends circumferentially between and makes contact with opposed surfaces of the assembly and the housing inner cavity. In an example, the interconnecting element 118 may be in the form of a canted coil spring that extends circumferentially within the housing inner cavity 104 between the housing 102 and the assembly outer ferrule 14, and specifically an outer surface of the outer ferrule skirt section 38. In an example, the canted coil spring is formed from and / or may be coated with an electrically conductive material capable of providing a desired electrical connection between the inner and outer ferrule assembly 10 and housing 102 to produce the desired shield grounding purpose. It is additionally desired that the canted coil spring be formed from a material capable of retaining its resilience to enable repeated use of the assembly and housing to provide the grounding electrical connection therebetween. Example materials useful for the canted coil spring include metals and metal alloys. In an example, the canted coil spring may be formed from and / or coated with copper and / or beryllium copper.

[0021] In an example, the canted coil spring 118 is disposed within a recessed groove or section 120 running circumferentially along the housing inner cavity 104 to maintain its placement therein and axial position when the assembly 10 is not disposed therein. In an example, the canted coil spring 118 is sized having a diameter that is sufficient to physically contact and compress against the outside surface of the outer ferrule skirt section when the assembly 10 is disposed within the housing. In an example, the outer ferrule shoulder section 36 has a degree of radially outward departure that operates to enable the assembly 10 to be moved axially within the housing inner cavity so as to engage the canted coil spring and place it into a compressed state against the outer ferrule skirt without binding. Because of the many interconnected rings extending circumferentially along and making up the canted coil spring 118, a robust electrical connection between the assembly 10 and housing 102 is assured. Further, the resilient nature of the canted coil spring and its compression against the outer ferrule operates to ensure that the electrical grounding connection between the assembly and housing forming the connector is maintained even when subjected to high levels of vibration.

[0022] FIG. 3 illustrates the example connector 100 as disclosed above and illustrated in FIG. 2. Specifically, the housing 102 inner cavity 104 is configured to accommodate placement of the assembly 10 therein comprising the combined inner ferrule 12 and the outer ferrule 14 with the cable shield portion 18 interposed and captured therebetween. Also clearly illustrated is the placement of the canted coil spring 118 within the recessed groove 120 of the inner cavity 104, and the placement of the canted coil spring circumferentially around and contacting the outside surface of the outer ferrule skirt section 38 providing a grounding electrical connection between the cable shield portion 18 captured by the assembly 10 and the housing 102 by the compression of the canted coil spring against the outer ferrule.

[0023] FIG. 4 illustrates an example shield grounding electrical connector 200 as disclosed herein comprising an inner and outer ferrule assembly 202 that is configured differently from that disclosed above and illustrated in FIG. 2. Specifically, the assembly 202 comprises an inner ferrule 204 that is configured in the form of an annular sleeve that is sized to fit over an axial end section of the shielded cable outer insulating sleeve 206 before or after a portion of the outer insulating sleeve has been removed to expose the cable shield portion 208. After the inner ferrule 204 is disposed onto the outer insulating sleeve 206, the exposed shield portion 208 is moved axially and along an outside diameter of the inner ferrule 204. An outer ferrule 210 comprising a neck section 212 is disposed concentrically over the cable shield portion 208 and inner ferrule 204, and the outer and inner ferrules are crimped together trapping the cable shield portion 208 therebetween to thereby form the assembly. The outer ferrule includes a radially outwardly extending shoulder section 214 that extends from the neck section 212, and that is a transition between the neck section 212 and a skirt section 216 that extends axially from the shoulder section.

[0024] As with the example shield grounding electrical connector disclosed above and illustrated in FIG. 2, a grounding electrical connection between the assembly 202 and the housing 218 is made through the use of an interconnecting element 220 that is interposed between the assembly and the housing inner cavity. The interconnecting element 220 is a canted coil spring that is disposed within a recessed section 222 running circumferentially along the housing inner cavity 224. Unlike the example illustrated in FIG. 2, the housing recessed section 222 operates in combination with a separate removable element 226 in the form of an annular spacer that is disposed within the housing from housing end 228 to abut against an axial edge 230 of the recessed section 222 to axially fix placement of the canted coil spring within the housing. A feature of this example assembly 202 is that both the inner and outer ferrules 204 and 210 are positioned along the same side of the shielded cable. Further, a sufficient length of the cable shield portion 208 is exposed so that it may extend along the length of the inner ferrule so that an end portion of the shield portion can be visually verified after the outer ferrule has been attached thereto. As with the example illustrated in FIG. 2, the connector outer ferrule shoulder section 214 is configured to engage and urge the canted coil spring thereover as the assembly is axially moved in the housing inner cavity and cause the canted coil spring to be compressed against the outer ferrule to form a desired grounding electrical connection that is robust and resistant to vibration.

[0025] FIG. 5 illustrates another example shield grounding electrical connector 300 comprising an inner and outer ferrule assembly 302 that is configured comprising an inner ferrule 304 in the form of an annular sleeve. The inner ferrule 304 is sized to fit over an axial end section of the shielded cable outer insulating sleeve 306 before or after a portion of the outer insulating sleeve has been removed to expose the cable shield portion 308. After the inner ferrule 304 is disposed onto the cable outer insulating sleeve 306, the exposed shield portion 308 is moved axially and along an outside diameter of the inner ferrule. An outer ferrule 310 comprising a neck section 312 is disposed concentrically over the cable shield portion, and the inner and outer ferrules are crimped together trapping the cable shield portion therebetween, thereby forming the assembly. The outer ferrule includes a shoulder section 314 that extends radially outwardly from the neck section 312, and that is a transition between the neck section 312 and a skirt section 316 that extends axially from the shoulder section.

[0026] A grounding electrical connection between the assembly 302 and the housing 318 is made through the use of an interconnecting element 320 interposed between the assembly and the housing inner cavity. In an example, the interconnecting element is a canted coil spring that is disposed within a recessed groove or section 322 running circumferentially along an outer surface of the outer ferrule skirt section 316. In an example, the recessed groove 322 is positioned adjacent an axial end 324 of the skirt section. Unlike the examples illustrated in FIGS. 2 and 3, the canted coil spring 320 in this example is retained on the assembly by the outer ferrule, and the desired electrical grounding connection between the assembly 302 and the housing 318 is made by insertion of the assembly within the housing inner cavity 326, and compression of the canted coil spring against the adjacent housing inner cavity surface. Like the example illustrated in FIG. 4, a feature of this assembly is that both the inner and outer ferrules are positioned along the same side of the shielded cable. Further, in an example arrangement, a sufficient length of the cable shield portion is exposed so that it may extend along a sufficient length of the inner ferrule so that an end portion of the shield can be visually verified after the outer ferrule has been attached thereto.

[0027] A feature of shield grounding electrical connectors as disclosed herein is the configuration of the inner and outer ferrules to capture the cable shield portion therebetween in a nested manner that prevents the shield portion from contacting the cable main conductor, and in a manner that can be visually confirmed. A further feature of such shield grounding electrical connectors is the use of an electrically interconnecting element in the form of a canted coil spring to provide a robust electrical connection between the inner and outer ferrule assembly and the rigid housing, by radial compression of the canted coil spring against the assembly and housing inner cavity to thereby provide the desired electrical grounding by the connector in a manner that is resistant to high vibrations present in certain end-use cable applications to provide a highly reliable grounding connection in such applications.

[0028] The foregoing description and accompanying figures illustrate the principles, preferred embodiments and modes of operation of the shield grounding electrical connectors as disclosed herein. However, such shield grounding electrical connectors should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiment discussed above will be appreciated by those skilled in the art. Therefore, the above-described embodiment should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to that embodiment can be made by those skilled in the art without departing from the scope of the shield grounding electrical connectors and connector housing constructions as defined by the following claims.

Claims

1. A cable shield connector (200) comprising: a cable (16) having a cable shield (208), an inner insulating sleeve (108) disposed radially inwardly from the cable shield (208), an inner conductor (112) radially inward of the inner insulating sleeve (108), and an outer insulating sleeve (206) disposed radially outwardly from the cable shield (208); an inner ferrule (204) having an inner surface and an outer surface, wherein the inner surface of the inner ferrule (204) is disposed over the outer insulating sleeve (206) and a portion of the cable shield (208) is disposed around a terminal end of the outer insulating sleeve (206) and onto and along at least a portion of the inner ferrule outer surface; an outer ferrule (210) comprising a first section (212) that is disposed concentrically around the inner ferrule (204) and wherein the portion of the cable shield (208) is interposed between and in direct contact with each of the inner ferrule (204) and the outer ferrule first section (212), wherein the outer ferrule (210) includes a second section (216) extending axially away from the first section (212) and having an enlarged diameter relative to the first section (212), the combined inner and outer ferrules (204, 210) forming an assembly (202); and a housing (218) having an inner cavity (224), wherein the assembly (202) is disposed within the inner cavity (224), characterized in that the outer ferrule (210) includes a radially outwardly extending shoulder section (214) that extends from the first section (212), and that is a transition between the first section (212) and the second section (216) that extends axially from the shoulder section (214); and the cable shield connector (200) includes an electrically interconnecting element (220) interposed between the assembly (202) and the cavity (224) to provide an electrical connection therebetween, the electrically interconnecting element (220) being in the form of a canted coil spring extending circumferentially between and contacting opposed surfaces of the assembly (202) and the housing inner cavity (224), and wherein the canted coil spring (220) is at least partially disposed within a recessed section (222) running circumferentially along the housing inner cavity (224), the canted coil spring (220) contacting the outer ferrule second section (216).

2. A method for providing an electrical connection with a cable shield connector (200), comprising the steps of: providing a cable (16) having a cable shield (208), an inner insulating sleeve (108) disposed radially inwardly from the cable shield (208), an inner conductor (112) radially inward of the inner insulating sleeve (108), and an outer insulating sleeve (206) disposed radially outwardly from the cable shield (208); providing an inner ferrule (204) having an inner surface and an outer surface, disposing the inner surface of the inner ferrule (204) over the outer insulating sleeve (206) and disposing a portion of the cable shield (208) around a terminal end of the outer insulating sleeve (206) and onto and along at least a portion of the inner ferrule outer surface; providing an outer ferrule (210) comprising a first section (212), disposing the first section (212) concentrically around the inner ferrule (204) and interposing the portion of the cable shield (208) between and in direct contact with each of the inner ferrule (204) and the outer ferrule first section (212), wherein the outer ferrule (210) includes a second section (216) extending axially away from the first section (212) and having an enlarged diameter relative to the first section (212), wherein the outer ferrule (210) includes a radially outwardly extending shoulder section (214) that extends from the first section (212), and that is a transition between the first section (212) and the second section (216) that extends axially from the shoulder section (214), the combined cable shield (18) and inner and outer ferrules (204, 210) forming an assembly (202); and inserting the assembly (202) into an inner cavity (224) of a housing (218) thereby causing a canted coil spring (220) extending circumferentially between the assembly (202) and the housing inner cavity (224) to make contact between opposed surfaces of the assembly (202) and the housing inner cavity (224) to form an electrical connection between the assembly (202) and housing (218), the canted coil spring (220) being an electrically conductive element interposed within an annular space between the housing inner cavity (224) and an outer surface of the assembly (202), the canted coil spring (220) being at least partially disposed within a recessed section (222) running circumferentially along the housing inner cavity (224), the canted coil spring (220) contacting the outer ferrule second section (216).

3. The method according to claim 2, wherein during the step of inserting the assembly (202), the assembly (202) is axially disposed into the housing inner cavity (224) causing the canted coil spring (220) to be compressed between the housing (218) and an outer surface of the assembly (202) to form the electrical connection therebetween.