JP2706829B2 - Electrical contact terminal - Google Patents

Description

The present invention relates to an electric contact terminal, and more particularly to an electric contact terminal made by stamping and molding and having an electric wire crimping portion.

[Conventional technology and its problems]

In forming a power or signal distribution (or power distribution) system, it is necessary to interconnect the various components or components of the system. This interconnection is typically made by an electrical connector having one or more electrical contact terminals.

The key requirement of the connector system is to be reliable and stable for a long period of 10 to 20 years.
Many integrated circuit (IC) systems require that the voltage drop in the system be less than 5%. Thus, each connection must be only a fraction of the total voltage drop, and the voltage drop (mV) of the connector must be minimal and remain constant for the life of the system.

As technology advances, the total termination (connection) resistance allowed by systems, including bulk, constriction, and crimping resistances, is decreasing, with many systems having less than about 10 mΩ total termination resistance. Therefore, it is necessary to design a contact member having a very low voltage drop at each connection point, particularly a power supply contact member. In order to meet this design requirement, the bulk resistance of the contact member is reduced as much as possible, the "constriction resistance", which is the resistance between the contact points or beams of the contact member, is reduced, and a low-resistance and stable wire (wire ) Must be terminated.

In designing the mating portion of the power contact member, it is preferable to use a plurality of spring (elastic) contacts that form a plurality of parallel current paths to reduce the voltage drop across all contact members. Therefore, the material selected for the contacts must have high electrical conductivity, excellent mechanical strength, sufficient tension, a beam with a small cross-sectional area, and low stress relaxation. This requires that the contact beam remain strong enough for the life of the contact.

U.S. Pat. No. 2,704,358 discloses a conventional contact for a power supply system having a solid barrel portion, a transition portion and a contact portion. The width of the material used in the transition between the contact and the barrel is narrow. Therefore, the current flowing through the contact portion flows from the narrow transition portion to the large body and the contact portion, and increases the resistance of the transition portion to cause a temperature rise. The very small cross-sectional area of the transition portion of the contact terminal overheats and thus functions substantially as a fuse. Therefore, it is desirable to have a contact terminal or contact portion that has an essentially constant cross-sectional area throughout the terminal.

U.S. Pat. No. 2,535,013 discloses a connector having a crimpable power contact terminal having a solid barrel portion made by welding seams of a molded member. Further, the solid barrel terminal may be made by well-known machining. Barrels with welded seams are suitable for terminal portions, such as those having blade-type contacts or terminals, and wires are bolted to the contacts. However, seam welded barrels are not suitable for regular contacts with compliant beams. The high temperatures required for welding high electrical and thermally conductive materials soften or anneal the metal in the flexible beam contacts, depriving the beam of elasticity and reducing its strength. Accordingly, it was desired to find a crimpable barrel connector means that did not require welding or joining of the seam, and acted essentially as a solid member without applying another solid tubular member to the seam.

[Object of the invention]

Accordingly, one of the objects of the present invention is to provide an electrical connector for a power supply system that is stable during the life of the system and that has low resistance.

It is another object of the present invention to provide a terminal which is stamped and formed, but which has a structure substantially equivalent to a solid barrel member.

It is yet another object of the present invention to provide a contact terminal having a substantially constant cross-sectional area over the entire length of the contact.

Another object of the present invention is to provide an electrical terminal having a plurality of contact paths for energization.

Another object of the present invention is to provide a substantially open, seamless electrical terminal member.

Yet another object of the present invention is to provide an inexpensive method for manufacturing an electrical contact terminal having a crimpable barrel portion.

[Summary of the Invention]

The present invention relates to an electric contact terminal formed by stamping and molding a single metal plate having a uniform thickness, comprising a hollow body portion, a forwardly protruding contact portion, and an opposing first portion.
And a second transition (connection) part and a barrel part. The first and second transition portions both project from the side of the hollow body in the same direction. The barrel portion includes first and second barrel portions and projects rearward from the first and second transition portions, respectively. The first barrel portion is nested within the second barrel portion, the seam of the first barrel portion is located in a different diametric direction from the seam of the second barrel portion, and the continuous portion of the second barrel portion is joined to the seam of the first barrel portion. To be located. After crimping the barrel to the wire, the barrel simulates a continuous angular body, and the first and second transitions improve the conduction of current from the terminal to the wire without overheating.

According to a preferred embodiment of the present invention, the contact portion comprises a plurality of cantilever spring contact beams extending forward from the hollow body portion. The hollow body has a substantially rectangular cross section. The cross section of the body portion may be any shape such as a circle, an ellipse, a triangle, and other polygons.

The present invention further discloses a method of stamping and forming a metal plate having a uniform thickness to form a terminal.

〔Example〕

Referring to FIGS. 1 to 7, the electrical contact terminal 10 includes a first body portion 12, a transition body portion 34.
And a barrel portion 48. To explain the present invention,
The body part 12 of the terminal part 10 has a rectangular cross section. Note that the terminal portion can take a variety of different shapes and that the hollow body portion can be, for example, cylindrical, elliptical, triangular, rectangular, or other polygonal.

The body 12 comprises first and second main sides 14,16 and sub-sides 18,20, as best shown in FIGS. A plurality of spaced first and second cantilever contact arms or beams 22, 24 project forward from the first and second major sides 14, 16, respectively. As best shown in FIGS. 4 to 6,
The minor side 20 is formed from two partial sides 19, 21 which meet at the seam 23 along the parts 19, 21 of the shaft ends 26, 28, respectively. In a preferred embodiment, edges 26, 28 include complementary tab members 30 and slot members 32 that alternately lock to hold edges 26, 28 together. It will be appreciated that the connector 10 is exemplary of a contact terminal according to the present invention and that the seam of the first portion may be retained by other means or not at all.

The transition section 34 includes first and second main side sections 14, 16 respectively.
First and second transition portions 36, 4 projecting rearward from
With 2. As best shown in FIG.
6,42 have sides 38,40 and 44,46 respectively directed inward. The width of the first and second transition portions 36, 42 is substantially equal to the cross-sectional area extending along the base of the contact beams 22, 24. The contact beams 22, 24 protrude from the transition portions 36, 42 along the main side portions 14, 16, respectively. First and second transition portions 36, 4 of the processed terminal
2 are separated from each other by spaces 39, 43 as shown in FIGS.

The barrel section 48 includes first and second barrel sections 50 and 56.
In the assembled terminal 10, the first barrel section 50 is nested in the second barrel section 56, and the joining ends 52, 54 of the first barrel section 50.
Is formed on the second barrel portion 56 at the joint end 5
Located substantially diametrically opposite seam 59 formed by 8,60. By having the seams 53,59 of the two barrel sections 50,56 in opposite positions of the assembled barrel section 48, the double barrel section 48 is substantially solid when barreled. Will work. As shown in FIGS. 2 and 3, when the conductor wire 70 is inserted into the barrel 48 and pressed and crimped, the inner solid barrel portion 50, which is basically aligned with the outer or seam 59 of the second barrel portion 56, The corresponding edges 58, 60 of the second barrel 56 are depressed downward, and the inner barrel portion 50 is sufficiently plastically deformed, but opposes springback, which is trying to return to its original shape. The cold weld (cold welding) and plastic deformation of the inner barrel 50 and the cold weld between the wire and the barrel 50 resist the outward movement, and exert the outward force on the joint edges 58 and 60 of the outer barrel 56. Substantially removes the joining edge 5
8,60 stay in the crimped position. U.S. Pat. No. 2,535,013 discloses the crimping method shown in FIG. FIG. 3 is a cross-sectional view of the terminal of the present invention, which is terminated (connected) to a wire 70 having a number of stranded wires therein.

The terminal of the present invention can be used for various wire sizes. In general, it is preferable to select the cross-sectional area of the contact terminal so that the wires connected to the terminal have the same thermal properties. As can be seen from FIGS. 2 and 3, the seam 59 formed by the joining edges 58, 60 of the outer barrel 56 is essentially aligned approximately at the center of the crimping section, and the center of the crimp is It is preferably plastically deformed below the horizontal axis. As a result, the stranded wire 72
Is forcibly pushed into two B-shaped portions 64 and 66.
This crimping force causes a cold weld between the first or inner wire barrel section 50 and the wire strand 72, which further helps to hold the wire barrel 48 in its crimped position. According to the present invention, it is preferred that the seam 59 of the outer barrel 56 be aligned approximately at the center of the crimp and maximize the amount of cold weld at the seam. Otherwise, the joining edges 58,6 of the outer barrel 56
0 causes unreasonable stress and is expanded outward. The crimp shown in U.S. Pat. No. 2,535,013 is designed for use with a single annular ring, such as a threaded solid or a seam welded molded part. When the barrel is crimped, sufficient pressure is applied and the outer surface is plastically deformed and substantially locked in place, with no stress dissipation to affect the function of the crimp barrel. This "locking" has heretofore been achieved only with solid rings, but according to the invention, the inner seamed ring undergoes a plastic deformation similar to a single-layer solid ring, so that the inner ring has its outer ring joined by a seam. It does not release stress as long as it is kept closed by cold welding around it.

As mentioned above, an electrical contact terminal having a compliant (elastic) beam as shown in FIG.
Heavy metal terminal bodies with high heat transfer capacity radiate heat from the seam and are difficult to solder or weld along the outer seam. Thus, if a flexible cantilever beam is brought to a temperature sufficient to soften or anneal its metal, the beam will lose its flexibility and lose its function.

It is important that there be a similar low resistance between the inner barrel portion 50 and the outer barrel portion 56 as between the wire 72 and the inner barrel portion 50 to ensure a parallel path of current. Accordingly, the entire surfaces of the inner and outer barrel members 50 and 56 physically and electrically maintain contact with each other, and are equal to the contact regions 22 and 24 from the transition portions 36 and 42 by the inner and outer portions 50 and 56 of the barrel portion 48. It is important to have resistance. Since the electrical (current) flows through the lowest resistance portion, the alternative current paths to both transitions 36, 42 provide a substantially equal current path. One way to ensure good engagement between each barrel surface is to use a fourth
As shown in FIG. 5 and FIG.
6 is to provide a plurality of irregularities (serrations) 57 on at least one surface. The irregularities 57 preferably run axially on the outer barrel portion 56 to create a plurality of contact surfaces between the barrel portions 50,56. Further, the unevenness 51 may be formed on the inner surface of the inner barrel portion 50 to ensure good cold welding of the stranded wire 72 to the barrel portion 50. The irregularities 57 are preferably formed on the inner surface of the outer barrel 56 to facilitate manufacture.

Another way that the outer barrel 56 ensures good mechanical and electrical engagement with the inner barrel 50 is to interconnect the edges of the outer barrel by other means without damaging the weld or the rest of the contacts. Is provided with a holding means.
As shown in FIG. 8, another embodiment 110 of the electrical contact terminal member includes a key member 161 and a dovetail slot 163 at the edges 158, 160 of the outer barrel portion 156 to connect the outer barrel 56 to the life of the terminal 110. Hold securely so that it does not open inside.

Again, because the material of the contacts is a good electrical and thermal conductor, the terminals radiate heat from the solder joints, making it impossible to use soldering as a means of holding the wires and terminals. Furthermore, this locking arrangement also eliminates the need to align the terminal within the crimping tool to ensure that the outer barrel contacts the inner barrel in locking engagement. The reason for this is that there is no potentially open seam that needs to be located exactly in the center of the crimp, as shown in FIGS.

Also, the present invention relates to a parallel contact (contact) for an electric current.
A path is provided to allow current to flow from the wire 70 through the inner barrel 50 and the first transition
The flow 56 and the second transition portion 42 are led to the first or second contact arms 22 and 24, respectively. Therefore,
The present invention does not have a fuse-like transition portion as in the conventional example.

4 to 7 show the steps of manufacturing the electrical contact terminal of the present invention shown in FIG. The connector 10 is preferably manufactured from a continuous metal strip, and a plurality of terminal blanks 80 shown in FIG. 4 are formed by stamping the metal strip. The blanks 80 are provided apart from each other along the carrier strip, not shown.
The terminal 10 first processes the blank 80 such that the first or inner wire barrel 50 is ring-shaped and the second or outer barrel 56 is U-shaped (see FIG. 5). Next, a partially molded terminal blank 80
Is rolled or formed (bent) to form the hollow body portion 12, and the edges 26, 28 of the main side portions 19, 21 of the terminal 10 are aligned to form the sub side portion 20, which is formed along with this The inner barrel portion 50 is accommodated in an open U-shaped outer barrel portion 56. Next, the outer barrel portion 56 is closed to form the terminal 10 of the present invention shown in FIG.

In the manufacture of this type of power contact, the requirements of the material used are to have a high conductivity, low stress release and sufficient normal force on the cantilever beam contacts. . Pure copper is preferred for the blade-shaped terminal member, but the molded member may be made of brass, has a flexible portion, and releases stress for a long time to reduce the amount of current that the terminal can flow. Those that are not suitable as terminal members. The stress relief properties of pure copper can reduce normal force by up to 50% over the life of the terminal.
Therefore, it is preferable to use a material having high conductivity and good mechanical properties. As this material, a material having a sufficiently high tension capable of forming a small cross section is preferable, and it is necessary that the stress release property is extremely low for a long time. Suitable materials include copper alloys, such as Olin C-151, manufactured by Olympus Corporation of East Alton, Illinois. This C-151 has a high electrical conductivity of 85 to 95% of pure copper, has extremely excellent mechanical properties such as tensile strength, and has a low stress release property, so that the crimped state is maintained throughout the life of the contact. . However, the piece of material need not necessarily be made of a single metal or alloy. The terminal may use a stamped piece of two types of welded metal plates, for example, the compliant beam part and the remaining part may be made of two types of metal.

The present invention provides an electrical contact terminal suitable for a power connector. The terminal has a plurality of contact beams to reduce the resistance of a portion having a contact portion, a barrel portion crimped to a wire, and at least two transition portions. This creates at least two parallel conductive paths to distribute the current to the contacts and prevent the "fuse effect" of conventional terminals.

The electrical contact terminal of the present invention is intended to mate with a complementary terminal member, such as a box or blade received between compliant beams, or with a box receiving a plurality of cantilever beams. doing.

As described above, the electric contact terminal of the present invention has been described in detail based on the preferred embodiment. However, various modifications and changes are possible without departing from the gist of the present invention, and various forms are possible according to applications. is there. That is, the greatest feature is that the crimping barrel portion of the electric contact terminal of the present invention has a double structure, and each joint (seam) is shifted from each other, for example, on the opposite side in the diameter direction. For example, the first
The barrel part and the second barrel part are not parallel (horizontal) but front to back (vertical)
As a relationship, one may be formed in a ring shape and then folded and overlapped with the other U-shaped barrel to form a double structure.

〔The invention's effect〕

As will be understood from the above description, the electrical contact terminal of the present invention has sufficient strength by using a relatively thin metal plate to make the barrel portion double-layered and the seams to be diametrically opposite to each other. It can be obtained easily and inexpensively without crimping barrel welding. A plurality of projections and depressions are formed in the overlapping portion of both barrels to increase the contact surface to minimize the current deviation and secure a large current capacity. Further, by making the contact arm upper and lower arms mutually shifted to form a finger assembly, it is possible to ensure sufficient contact with a plate-like or blade-like contact such as a bus bar.

[Brief description of the drawings]

FIG. 1 is a perspective view of a preferred embodiment of the electric contact terminal of the present invention, FIG. 2 is a partial cross-sectional view of the barrel portion of the electric contact terminal of FIG. 1 in which a stranded wire is inserted into the barrel portion, 3 is a view in which the wire barrel portion of FIG. 2 is crimped, FIGS. 4 to 7 are manufacturing process diagrams of the electrical contact terminal shown in FIG. 1, and FIG. 8 is another embodiment of the electrical contact terminal of the present invention. It is a perspective view of an example. 50 First barrel part (inner barrel part) 53, 59 Joint part (seam) 56, 156 Second barrel part (outer barrel part)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor James Henry Wise 17078 Palmyra, PA, United States 607 (56) References JP-A-51-130887 (JP, A) 5374 (JP, U)

Claims (1)

(57) [Claims] An inner barrel portion formed by bending a metal plate into a substantially cylindrical shape; and an outer barrel portion formed by bending the metal plate and contacting the outer side of the inner barrel portion in at least a plurality of regions. An electrical contact terminal, comprising: a wire connection barrel having: a seam of the inner barrel portion and a seam of the outer barrel portion are offset from each other.