JPH02223164A - Electric contact terminal - Google Patents

Abstract

PURPOSE: To widen a contact surface and minimize any shift of electric current so as to secure a large current capacity by dually structuring a barrel part using a comparatively thin metallic plate and setting joints in the mutually radially opposite directions. CONSTITUTION: A plurality of irregularities 57 are provided on the surface of at least one side of barrel parts 50, 56 making mutual contact. The irregularities 57 are allowed to run in the axial direction in the outside of the barrel part 56, plural contact surfaces are generated between barrel parts 50, 56, further irregularities 51 are formed also on the inner surface of the inside of the barrel part 50 and satisfactory cold welding of wire strand 72 is ensured on the barrel part 50. Furthermore, joints 53, 59 of two barrel parts 50, 60 are made to come to a position opposite to an assembled barrel part 48 so as to crimp the double barrel part 48 and substantially it may function as a fixed barrel. In this way, a connector stable and having a low resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrical contact terminals, and more particularly to electrical contact terminals made by stamping and molding and having wire crimps.

[Prior art and its problems]

When forming a power supply or signal distribution (or power distribution) system,
There is a need to make interconnections between various parts or parts of the system. This interconnection is typically made by an electrical connector having one or more electrical contact terminals.

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

As technology advances, the total termination resistance allowed by systems including bulk, constriction, and crimp resistors has decreased, with many systems having a total termination resistance of about 10 mΩ or less.

Therefore, it is necessary to design a contact member, especially a power supply contact member, with extremely low voltage drop at each connection point. In order to meet this design requirement, we reduced the bulk resistance of the contact member as much as possible, lowered the "constriction resistance" which is the resistance between the contact points or beams of the contact member, and used low-resistance and stable wires (electrical wires). ) must be terminated (connected).

When designing the power contact member mating portion, it is preferred to use multiple spring (resilient) contacts that form multiple parallel current paths to reduce the voltage drop across all contact members. Therefore, the material selected for the contact must have high electrical conductivity, excellent mechanical strength, sufficient tension, be able to form a beam with a small cross-sectional area, and have low stress relaxation. This requires that the contact beam continue to have sufficient strength throughout the life of the contact.

U.S. Pat. No. 2,704,358 discloses a conventional contact for a power 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 section and the barrel section is narrow. Therefore, the current flowing through this contact flows from the narrow transition into the larger body and contact, increasing the resistance of the transition and causing a rise in temperature. The extremely small cross-sectional area of the transition part of the contact terminal becomes so heated that it essentially functions as a fuse. It is therefore desirable to have a contact terminal or contact portion with 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 the seam of a molded member. Solid barrel terminals may also be made by well-known machining processes. The seam welded barrel is suitable for terminals such as those having blade-type contacts or terminals, and the wire is bolted to the contacts.

However, seam-welded barrels are not suitable for conventional contacts with compliant beams.

The high temperatures required to weld highly electrically and thermally conductive materials soften or anneal the metal of the flexible beam contact, making the beam less elastic and less strong.

Accordingly, it would be desirable to find a crimpable barrel connector means that would essentially act as a solid member without requiring seam welding or bonding and without applying a separate solid tubular member to the seam.

[Purpose of the invention]

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

Another object of the invention is to provide a terminal that is stamped and formed but of substantially equivalent construction to a solid barrel member.

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

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

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

Yet another object of the invention is to provide an inexpensive method for manufacturing electrical contact terminals with crimpable barrel portions.

[Summary of the invention]

The present invention is an electrical contact terminal formed by punching and molding a single metal plate of various thicknesses, the terminal having a hollow body portion, a contact portion protruding forward, and first and second transitions facing each other. It has a (connection) part and a barrel part. The first and second transsilane parts both protrude in the same direction from the sides of the hollow positive part. The barrel portion includes first and second barrel portions that project rearward from the first and second transition portions, respectively. The first barrel section is nested within the second barrel section, such that the seam of the first barrel section is located at a different diameter from the seam of the second barrel section, and the continuous portion of the second barrel section is nested within the seam of the first barrel section. position. After crimping the barrel section to the wire, the barrel section simulates a continuous angular body, and the first and second transition sections improve the conductivity of current from the terminal to the wire without overheating.

According to a preferred embodiment of the invention, the contact portion includes a plurality of cantilevered spring contact beams extending forwardly from the hollow body portion. The hollow body portion has a generally rectangular cross section. The cross section of the body portion may be any shape such as circular, elliptical, triangular, or other polygonal shape.

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

〔Example〕

Referring to FIGS. 1-7, electrical contact terminal 10 includes a first body portion 12, a transition body portion 34, and a barrel portion 48. Referring to FIGS. For purposes of explaining the invention, the body portion 12 of the terminal portion 10 has a rectangular cross section. It should be noted that the terminal portion can have a variety of different shapes and that the hollow body portion can be, for example, cylindrical, elliptical, triangular, rectangular or other polygonal.

The first section 12, as best shown in FIGS. 1 and 4, includes:
It consists of first and second major sides 14.16 and minor sides 18.20. A plurality of spaced apart first and second cantilevered contact arms or beams 22.24 project forwardly from the first and second main sides 14.16, respectively. As best shown in FIGS. 4 to 6, the secondary side 20 has two partial sides 19.21.
are formed, respectively, meeting at a seam 23 along portions 19.21 of the axial ends 26.28. In a preferred embodiment, edge 26
．． 28 includes complementary tab members 30 and slot members 32 that lock together to hold edges 26.28 together. It will be appreciated that 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 portion 34 includes the first and second main side portions 14,
16 having first and second transition portions 36, 42 projecting rearwardly from the transition portion 16. As best shown in FIG.
0 and 44.46. The first and second transition portions 36.42 have a width approximately equal to the cross-sectional area extending along the base of the contact beam 2224. The contact beams 22.24 project from the transition portions 36.42 along the main sides 14.16, respectively. The first and second transition portions 36.42 of the machined terminal are separated from each other by a space 39.43 as shown in FIGS. 2 and 3.

Barrel section 48 consists of first and second barrel sections 50,56. In the assembled terminal 10, the first barrel portion 50
is nested in the second barrel part 56, and the seam 53 formed by the joining end 52.54 of the first barrel part 50 is substantially opposite to the seam 59 formed by the joining end 58.60 in the second barrel part 5G. located diametrically. A double (
The double barrel portion 48 essentially functions as a solid barrel when crimped.

As shown in FIGS. 2 and 3, when the conductor wire 70 is inserted into the barrel 48 and crimped with pressure, the inner solid barrel portion 50 is essentially aligned with the seam 59 of the outer or second barrel portion 56. Corresponding edge 5B of second barrel 56
, 60 are forced downwardly, and the inner barrel portion 50 is sufficiently plastically deformed to resist springback as it tries to return to its original shape. The cold weld and plastic deformation of the inner barrel 50 and the cold weld between the wire and the barrel 50 resist outward movement and exert outward forces on the mating edges 5B, 60 of the outer barrel 56. substantially removing the joining edge 58
．． 60 remains in the crimped position. U.S. Pat. No. 2,535,013 discloses a crimping method as shown in FIG. FIG. 3 is a cross-sectional view of the terminal of the present invention, which is terminated with a wire 70 having multiple strands therein.

The terminal of the present invention can be used with a variety of wire sizes. It is generally preferable to choose the cross-sectional area of the contact terminal so that the terminal and the wire to which it is connected have the same thermal properties. As can be seen in FIGS. 2 and 3, the seam 59 formed by the mating edges 58,60 of the outer barrel 56 is essentially aligned approximately to the center of the crimp, and the center of the crimp is located on the barrel 48. The plastic deformation is preferably below the horizontal axis. This forces the wire strand 72 into the two figure-eight portions 64, 66. This crimp force creates a cold weld between the first or inner wire barrel portion 50 and the wire strands 72, which further assists in holding the wire barrel 48 in its crimp position. According to the present invention, it is preferred that the seam 59 of the outer barrel 56 be aligned generally with the core of the crimp to maximize the amount of cold welding at the seam. Otherwise, it would cause undue stress on the mating edges 58,60 of the outer barrel 56 causing them to expand outwardly. U.S. Patent No. 2.53
The crimp shown in No. 5.013 is designed to be used with a single annular ring, such as a threaded solid or seam welded molded member. Once the barrel is crimped,
Sufficient pressure is applied and the outer surface undergoes plastic deformation to essentially lock it in place, without stress dissipation to the extent that it affects the function of the crimp barrel.

Until now, this [locking] could only be achieved with solid rings. However, according to the present invention, the inner seamed ring undergoes plastic deformation similar to that of a single layer solid ring, and thus the inner ring will remain closed as long as the outer ring is held closed by cold welding around the seam. Does not cause stress relief.

As previously mentioned, electrical contact terminals with compliant beams, such as those shown in Figure 1, should not be soldered or welded along the outer seams because the heavy metal terminal body with high thermal conductivity radiates heat from the seams. difficult to do.

Thus, exposing a flexible cantilever beam to a temperature sufficient to soften or anneal the metal will cause the beam to become inflexible and lose its functionality.

It is important that there is a similar low resistance between the inner barrel section 50 and the outer barrel section 56 as there is between the wire 72 and the inner barrel section 50 to ensure a parallel path for the current.

Thus, the entire surfaces of the inner and outer barrel members 50.56 remain in physical and electrical contact, and the inner and outer portions 50.56 of the barrel portion 48 allow the transition portion 36.
It is important to have equal resistance from 42 to contact region 22.24. The alternate current paths to both transition portions 3642 provide substantially equal current paths since electricity (current) flows through the lowest resistance portion. One way to ensure good engagement between each barrel surface is to minimize the number of barrel portions 50, 56 that contact each other (with multiple serrations on one surface, as shown in FIGS. 4 and 5). ) 57. Preferably, the asperities 57 run axially on the outer barrel portion 56, creating a plurality of contact surfaces between the barrel portions 50,56. Asperities 51 may be formed to ensure good cold welding of the wire strands 72 to the barrel portion 50. For ease of manufacture, the asperities 57 are preferably formed on the inner surface of the outer barrel 56.

Another way to ensure good mechanical and electrical engagement of the outer barrel 56 with the inner barrel 50 is to join the edges of the outer barrel together by welding or other means that do not cause damage to the rest of the contact. It is necessary to provide a means for holding it in place. As shown in FIG. 8, another embodiment of the electrical contact terminal member 110 includes an edge 158.1 of the outer barrel portion 56.
60 includes a key member 161 and a dovetail slot 163;
The two are connected to ensure that the outer barrel 56 does not open during the life of the terminal 110.

Again, the contact material is a good electrical and thermal conductor, so the terminal will radiate heat away from the solder joint.
It is not possible to use soldering as a means of holding wires and terminals.

Additionally, this locking configuration also eliminates the need to align the terminal within the crimping tool, since the outer barrel securely contacts the inner barrel in a 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. 2 and 3.

The present invention also provides parallel contact paths for current flow from the wire 70 through the inner barrel section 50 and the first transition section 36 or through the outer barrel section 56 and the second transition section 42. and lead to the first or second contact arms 22 and 24, respectively. Therefore, the present invention does not have a fuse-like transition section unlike the conventional example.

4 to 7 illustrate the manufacturing process of the electrical contact terminal of the present invention shown in FIG. The connector IO is preferably manufactured from a continuous metal strip, from which a plurality of terminal blanks 80, shown in FIG. 4, are stamped.

Although not shown, the blanks 80 are provided spaced apart from each other along the carrier strip. The terminal IO first connects the blank 80 to the first or inner wire barrel portion 50.
is formed into a ring (annular shape), and the second or outer barrel portion 56 is processed into a U-shape (see FIG. 5). Next, the partially molded terminal blank 80 is rolled or molded (folded) to form the hollow body portion 12, and the edges 26, 28 of the main side portion 19° 21 of the terminal 10 are aligned and A U-shaped outer barrel portion 5 that forms the side portion 20 and has an inner barrel portion 50 formed therewith in an open state.
It can be kept within 6.

The outer barrel portion 56 is then closed to form the terminal IO of the present invention as shown in FIG.

In the manufacture of this type of power contact, the requirements for the material used are that it has high electrical conductivity, low stress relief and sufficient normal force in the cantilevered beam contact area. .

Although pure copper is preferred for blade-shaped terminal members, the molded member may also be made of brass, which allows the flexible portion to remain open and relieve stress over time, reducing the amount of current that the terminal can carry. Those that do are unsuitable as terminal members. The stress relief properties of pure copper can reduce normal forces by up to 50% over the life of the terminal. Therefore, it is preferable to use materials with high electrical conductivity and good mechanical properties. The material should preferably be sufficiently high tensile to form small cross-sections and should have very low stress relief properties over long periods of time. A suitable material is Olin e manufactured by Oritz Brass, East Aldon, Illinois.
There are copper alloys such as -151.

This C-151 has a high electrical conductivity of 85 to 95% that of pure copper, has extremely excellent mechanical properties such as tensile strength, and has low stress release properties, so the crimped state is maintained throughout the life of the contact. . However, the piece of material does not necessarily have to be made of a single metal or alloy. The terminal may be made of stamped pieces of two metal plates that are welded together, for example the compliant beam section and the remaining parts may be made of two metals.

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 the contact section, the barrel section that is crimped onto the wire, and the section that has at least two transition sections. This creates at least two parallel conductive paths to distribute current to the contacts and to prevent the "fuse effect" of conventional terminals.

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

Although the electrical contact terminal of the present invention has been described in detail above based on its preferred embodiments, various modifications and changes can be made without departing from the gist of the present invention, and various forms can be made depending on the application. be. That is, the crimping barrel portion of the electrical contact terminal of the present invention has a double structure,
The main feature is that the joints (seams) are offset from each other, for example, on opposite sides in the diametrical direction. For example, the first barrel part and the second barrel part are not parallel (horizontal) but front to back (vertical), and one part is formed into a ring shape, and then folded over the other U-shaped barrel to form a double structure. good.

〔Effect of the invention〕

As can 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 part double-layered and having seams in diametrically opposite directions. Can be easily and inexpensively obtained without crimp barrel welding. Multiple concavities and convexities are formed on the overlapping portion of both barrels to increase the contact surface, minimize current flow, and ensure large current capacity. Furthermore, by making the contact arm into a finger-combined shape by shifting the upper and lower arms relative to each other, it is possible to ensure sufficient contact with a plate-shaped or blade-shaped contact such as a bus bar.

[Brief explanation of the drawing]

1 is a perspective view of a preferred embodiment of the electrical contact terminal of the present invention; FIG. 2 is a partial cross-sectional view of the barrel portion of the electrical contact terminal of FIG. 1 with wire strands inserted into the barrel portion; 3 is a view of the wire barrel portion of FIG. 2 crimped; FIGS. 4 to 7 are manufacturing process diagrams of the electrical contact terminal shown in FIG. 1; FIG. 8 is another implementation of the electrical contact terminal of the present invention. FIG. 3 is a perspective view of an example.

Claims (1)

[Claims] (1) An inner barrel portion formed by bending a metal plate into a substantially cylindrical shape; and an outer barrel portion formed into a substantially cylindrical shape by bending a metal plate and contacting the outside of the inner barrel portion in at least a plurality of areas. An electrical contact terminal comprising: a wire connection barrel having a wire connection barrel, wherein a bonding edge of the first barrel portion and a bonding edge of the second barrel portion are formed at substantially opposite positions of the barrel.