Process for manufacturing a female electrical terminal for a power connector

Abstract

A process for manufacturing a female power terminal (1), intended to be accommodated in a power connector (100), comprising - forming a terminal body having a base body (2) and a contact body (3), the contact body (3) comprising a cavity (22) configured to mate with a portion of a male terminal, - forming a contact sleeve (4) made of a conductive material, - inserting the contact sleeve (4) in said cavity (22), so that the contact sleeve (4) extends, along a direction parallel to the longitudinal axis (A), between a distal end and a proximal end. The contact body (3) is made by cold-forging, and the contact sleeve (4), inserted in the cavity (22), is blocked at one end by a stop ring (17) inserted in the cavity (22) and at the other end, by the contact body (3).

Description

TECHNICAL FIELD

[0001] The disclosure relates to the field of power connection systems for motor vehicles. For example, the disclosure can find an application in power connectors, such as those used to charge a battery for rechargeable electric or hybrid vehicle or as those used in interconnect power circuits connecting batteries, converters, electrical motors, and any other power device of a vehicle.BACKGROUND

[0002] In the field of power connection systems for motor vehicles, the female terminals are often machined by bar turning from a bar of conductive material, for example a copper alloy. The female terminals can also be made by cutting, stamping and embossing a blank in an electrically conductive material in sheet, and rolling up a cut-out region of the blank.

[0003] The machining by bar turning is a relatively long process and generates a relatively large amount of material waste. Therefore, it is a relatively expensive process.

[0004] A purpose of the present disclosure is to propose an alternative method for manufacturing a female terminal that at least partially mitigates at least one drawback of a prior art method.SUMMARY

[0005] It is disclosed below a process for manufacturing a female power terminal intended to be accommodated in a power connector.

[0006] Advantageously, this process comprises the steps of separately forming a terminal body and a contact sleeve. More particularly, the terminal body comprises a base body and a contact body. The base body and the contact body consist of two distinct parts, both being made of a conductive material. The base body is configured to be mechanically and electrically connected to a conductor (e.g., a cable, a busbar, etc.). The contact body comprises a cylindrical cavity extending along a longitudinal axis. This cavity is configured to mate with a portion of a male terminal.

[0007] The contact sleeve is also made of a conductive material. The contact sleeve is inserted in said cavity, so that the contact sleeve extends, along a direction parallel to the longitudinal axis, between a distal end and a proximal end. For example, the contact sleeve comprises resilient lamellae that contribute to improve the performances of the terminal in terms of electrical conductivity and insertion force.

[0008] Further, at least the contact body is made by cold-forging.

[0009] Cold forging processes make it possible to form parts quickly and without wasting material. Advantageously, the contact sleeve, when inserted in the cavity, is blocked at its proximal end by a stop ring inserted in the cavity and at its distal end, by the contact body.

[0010] This female terminal optionally further comprises any of the following features, considered independently of one another or in combination with one or more others. the base body and a contact body are made of copper or a copper alloy; copper has properties that are suitable for conducting high currents while limiting overheating; moreover, it is a material that is compatible with the production of simple shapes by cold forging, as well as with crimping or soldering processes and it does not present any electrochemical potential problems when connected to a copper cable; it comprises a step of plating the base body and a contact body, each with a different conductive material; for example, the base body can be plated with tin and the contact body can be plated with silver; therefore, the advantage of having two separate parts is that they can be plated separately using materials optimised for the particular function of each part (silver provides a better electrical conduction through contact between the contact sleeve and the contact body, while tin provides a better electrical conduction with the cable in the crimping or soldering area) ; the stop ring is made of steel; steel offers a greater resilience to form lamellae ; the base body is made as a single part; although the base body can be made in several parts, for ease of assembly in particular, it is preferable to make it in a single piece; it comprises a step of cold-forging the base body; as already explained, cold forging processes avoid material waste; in addition, the cold forging process enables a rapid production of each part; the base body comprises a distal wall, and said process comprises a step of press-fitting the contact body in the base body.

[0011] It is also disclosed a female power terminal, intended to be accommodated in a power connector, this terminal comprising a terminal body, and this terminal body comprising a base body, a contact body, and a contact sleeve, the base body, the contact body, and the contact sleeve being made of a conductive material, the base body being configured to be mechanically and electrically connected to a conductor, and the contact body comprising a cylindrical cavity extending along a longitudinal axis and configured to mate with a portion of a male terminal, the contact sleeve being inserted in said cavity, so that the contact sleeve extends, along a direction parallel to the longitudinal axis, between a distal end and a proximal end. Further, the contact body is made by cold-forging, and the contact sleeve, when inserted in the cavity, is blocked at its proximal end by a stop ring inserted in the cavity and at its distal end, by the contact body.

[0012] It is also disclosed a power connector having a housing comprising at least one cavity in which a female power terminal as mentioned above is accommodated, the base body of said female power terminal being electrically and mechanically connected to a conductor, said conductor being a cable or a busbar.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Others features, details and advantages of the invention will become more apparent from the detailed illustrating description given hereafter with respect to the drawings on which: Figure 1 shows a schematic perspective view, from the mating face, of an example of a connector in which two female power terminals are accommodated; Figure 2 shows a schematic cross-sectional view of an example of a female terminal such as that housed in the connector in Figure 1, this female terminal being shown mated with a portion of a male terminal; Figure 3 shows a schematic perspective view of an example of a female terminal; and Figure 4 shows a schematic cross-section of the female terminal in Figure 3. DETAILED DESCRIPTION

[0014] This disclosure relates to female electrical contact terminals 1 for conveying a high current.

[0015] A terminal 1 of this type can be, for example, accommodated in a female power connector 100 (see Figure 1). Such a connector 100 comprises for example a housing 101 made of dielectric material and has at least one cavity 102. In the example illustrated in Figure 1, the housing 101 has two cavities 102. A terminal 1 is accommodated in each cavity 102. Each terminal 1 is electrically and mechanically connected to a conductor 103. In the example illustrated in Figure 1, the conductor 103 is a power cable. The connector 100 has a mating interface 104 configured to mate with a male connector (not illustrated). The mating interface 104 and each terminal 1 are together configured to provide an IPXX protection.

[0016] Each terminal 1 comprises at least a base body 2, a contact body 3 and a resilient contact sleeve 4 inserted in the contact body 3 (see Figures 2 to 4). The base body 2 and the contact body 3 form a terminal body.

[0017] The base body 2 is essentially in the form of a cylindrical tube of revolution about a longitudinal axis A. The base body 2 itself comprises two portions: a cable attachment portion 5 and a connection portion 6.

[0018] The cable attachment portion 5 is configured to receive a free end of a cable 103, this end having been stripped beforehand. The cable attachment portion 5 is configured to allow this end to be mechanically and electrically connected to the base body 2, using a known technique such as crimping or welding technology (for example, Electro Magnetic Pulse Technology welding. i.e., EMPT welding). Advantageously, the cable attachment portion 5 comprises a cylindrical proximal wall 7 that is circularly symmetrical about the longitudinal axis A. For example, this proximal wall 7 has a thickness of 2 mm (before crimping over the cable). Advantageously, at least one zone of the internal tubular surface of this proximal wall 7 is coated with a layer of nickel, then with a layer of tin. Of course, when connected to a busbar the shape of the base body in its region corresponding to the attachment portion, is different from the one shown in the Figures. For example, this region can be flattened.

[0019] The connection portion 6 is configured to receive the contact body 3. The connection portion 6 also has a cylindrical distal wall 18 that is circularly symmetrical about the longitudinal axis A. The connection portion 6 and the cable attachment portion 5 are internally separated by a partition wall 8 perpendicular to the longitudinal axis A.

[0020] The connection portion 6, the cable attachment portion 5 and the partition wall 8 thus form the base body 2. The base body 2 is a single piece (alternatively, it is made of at least two parts assembled by friction welding or screwing, etc.). For example, the base body 2 is made by cold forging or machining. For example, the base body 2 is made of copper or a copper alloy.

[0021] The contact body 3 is also essentially in the form of a cylinder of revolution about the longitudinal axis A. The contact body 3 comprises a cylindrical cavity 22 extending along the longitudinal axis A. For example, the contact body 3 is made from a single piece of copper or copper alloy. The contact body 3 is advantageously made by cold forging. The contact body 3 comprises a contact wall 9. The contact wall 9 is circularly symmetrical about the longitudinal axis A, one longitudinal end of which is provided with a collar 10. This collar 10 is formed at the distal end 11 of the contact body 3 (i.e. its longitudinal end which is not inserted into the connection portion 6). This collar 10 has an outer edge 12 and an inner edge 13. The inner 13 and outer 12 edges extend substantially parallel to the radial direction (relatively to the longitudinal axis A). The inner edge 13 extends radially in the direction of the longitudinal axis A. The outer edge 12 extends radially outwards from the contact body 3. The contact body 3 is inserted into the connection portion 6 over all or part of its length (parallel to the longitudinal axis A). The contact body 3 is press-fitted into the connection portion 6.

[0022] The contact sleeve 4 is essentially in the form of a cylinder centred on the longitudinal axis A. For example, the contact sleeve 4 is made of made of a copper / beryllium alloy. The contact sleeve 4 has a ring 14, 15 at each of its longitudinal ends. Multiple elastic lamellae 16 extend between the two rings: a distal ring 14 and a proximal ring 15. The lamellae 16 are slightly arched towards the longitudinal axis A so that a constriction is formed roughly half way between the rings 14, 15. At this constriction, the contact sleeve 4 is meant to contact a complementary male pin 200 when the latter is inserted into the contact body 3.

[0023] One of the rings 14, 15 (the distal ring 14) abuts the inner edge 13, so as to prevent the contact sleeve 4 from being removed from the contact body 3. Advantageously, the contact sleeve 4 is also held inwards (towards the partition wall 8) in the direction parallel to the longitudinal axis A, in order to prevent the contact sleeve 4 from being pushed towards the bottom of the connection portion 6. To do so, a stop ring 17 is placed inside the contact body 3. For example, the stop ring 17 is essentially in the form of a cylinder centred on the longitudinal axis A. One of the longitudinal ends of the stop ring 17 abuts the partition wall 8. Advantageously, the contact body 3 abuts the other longitudinal end of the stop ring 17. The stop ring 17, the proximal ring 15 and the contact body 3 are configured so that the contact sleeve 4 is tightly maintained in a direction parallel to the longitudinal direction A, between the contact body 3 and the stop ring 17. The stop ring 17 comprises a cylindrical wall 18, the thickness of which is less than the thickness of the contact wall 9, thereby the proximal ring 15 of the contact sleeve 4 abuts an edge of the stop ring 17. For example, the stop ring 17 is made of steel.

[0024] The distal wall 18 is 1.4mm thick.

[0025] Optionally, the terminal 1 is equipped with a central finger 19 extending longitudinally parallel to the longitudinal axis A. At its distal end (free end), the central finger 19 supports a plastic cap 24. The plastic cap 24 provides an IPXX protection with the insulating housing 101, when the female terminal 1 is mounted in this housing 101. For example, the central finger 19 is made of steel and is press-fitted in a hole 20 formed in the partition wall 8.

[0026] The manufacturing process of the terminal 1 comprises for example (see figure 5): a step 1010 of cold forming the base body 2; a step 1020 of cold forming the contact body 3; a step 1030 of cold forming the contact sleeve 4; a step 1040 of forming (or simply providing) the stop ring 17; an optional step 2000 of the mounting the plastic cap 24 on the central finger 19 and of press-fitting the central finger 19 into the hole 20; a step 3000 of inserting the stop ring 17 in the base body 2 (with a clearance between the stop ring 17 and the base body 2); a step 4000 of press-fitting the contact body 3 in the base body 2; and a step 5000 of inserting the contact sleeve 4 in the contact body 3 (there is an interference between the contact sleeve 4 in the contact body 3).

Claims

1. A process for manufacturing a female power terminal (1), intended to be accommodated in a power connector (100), this process comprising the steps of - forming a terminal body comprising a base body (2) and a contact body (3), both being made of a conductive material, the base body (2) being configured to be mechanically and electrically connected to a conductor (103), and the contact body (3) comprising a cylindrical cavity (22) extending along a longitudinal axis (A) and configured to mate with a portion of a male terminal (200), - forming a contact sleeve (4) made of a conductive material, - inserting the contact sleeve (4) in said cavity (22), so that the contact sleeve (4) extends, along a direction parallel to the longitudinal axis (A), between a distal end and a proximal end, characterized in that at least the contact body (3) is made by cold-forging, and contact sleeve (4), inserted in the cavity (22), is blocked at its proximal end by a stop ring (17) inserted in the cavity (22) and at its distal end, by the contact body (3).

2. The process according to claim 1, the base body (2) and a contact body (3) are made of copper or a copper alloy.

3. The process according to claim 2, comprising a step of plating the base body (2) and a contact body (3), each with a different conductive material.

4. The process according to claim 1 or 2, wherein the stop ring (17) is made of steel.

5. The process according to any one of the preceding claims, wherein the base body (2) is made as a single part.

6. The process according to any one of the preceding claims, comprising a step of cold-forging the base body (2).

7. The process according to any one of the preceding claims, wherein the base body (2) comprises a distal wall (18), and said process comprises a step of press-fitting press-fitting the contact body (3) in the base body (2).

8. A female power terminal (1), intended to be accommodated in a power connector (100), this terminal (1) comprising a terminal body, and this terminal (1) body comprising a base body (2), a contact body (3), and a contact sleeve (4), the base body (2), the contact body (3), and the contact sleeve (4) being made of a conductive material, the base body (2) being configured to be mechanically and electrically connected to a conductor (103), and the contact body (3) comprising a cylindrical cavity (22) extending along a longitudinal axis and configured to mate with a portion of a male terminal (200), the contact sleeve (4) being inserted in said cavity (22), so that the contact sleeve (4) extends, along a direction parallel to the longitudinal axis, between a distal end and a proximal end, characterized in that at least the contact body (3) is made by cold-forging, and the contact sleeve (4), inserted in the cavity (22), is blocked at its proximal end by a stop ring (17) inserted in the cavity (22) and at its distal end, by the contact body (3).

9. A power connector having a housing comprising at least one housing cavity (102) in which a female power terminal (1) according to any of the preceding claims is accommodated, the base body (2) of said female power terminal (1) being electrically and mechanically connected to said conductor (103), said conductor (103) being a cable or a busbar.

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