JPS5854470B2 - connector contacts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connector contact for low current or communication that requires high reliability.

Generally, in connector contacts for low current or communications, the signal voltage is at a low level, so if a film of oxide, sulfide, etc. exists on the contact surface, it is difficult to electrically destroy this film.

In addition, since the contact surface of this type of conventional contact is a spherical or cylindrical surface, the surface coating cannot be mechanically destroyed simply by pressing.

In this case, the coating can be mechanically destroyed by sliding the contact surface, but with base metal contacts, stable and sufficient electrical continuity is difficult to obtain even with this method.

For this reason, conventional connector contacts use gold or gold alloys, which are expensive but have little effect on coating, and sufficient attention is paid to their surface treatment.

This invention was made against the above-mentioned conventional technical background, and therefore, an object of the invention is to mechanically remove the coating even in contacts that use base metals and have a surface coating. The object of the present invention is to provide a connector contact for weak current or communication that can be broken to provide stable electrical continuity.

The key point of the structure of the present invention is that a needle-like contact and a flat-plate contact are opposed to each other, and by pushing the needle-like contact into the flat-plate contact so that it sticks up, stable electrical continuity is obtained between both contacts. .

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

In FIG. 1, 1 is a needle-like contact, 2 is a flat contact, and 3 is a surface coating.

When the needle contact 1 is pushed into the flat contact 2, the surface coating 3 is destroyed by the relative sliding at that time, and electrical continuity can be established between both contacts.

FIG. 2 is a cross-sectional view schematically showing the contact situation of a conventional contact, and 4 indicates a hemispherical contact.

As can be seen in Figure 2, the conventional method is to press the hemispherical contact 4 against the flat contact 2 to make contact, so the presence of the surface film 3 results in the advantage of electrical continuity between both contacts. In many cases, conduction was not achieved, and even when conduction was obtained, the conduction was not stable and exhibited contact resistance characteristics with extremely large variations.

Like the connector contact according to the present invention, a needle contact whose tip has a sharp shape based on a cone, pyramid, or wedge shape and is made of a relatively hard material is replaced with a flat contact made of a material with a lower hardness. By pushing the connector in an upright manner, stable contact resistance characteristics with less variation than conventional connector contacts can be obtained, and low contact resistance can be obtained even in contacts with surface coatings.

FIG. 3 is a diagram for explaining the effect of the connector contact according to the present invention, and the horizontal axis represents the conical apex angle 2 of the conical needle contact.
The opening degree is taken as α, and the contact resistance is taken on the vertical axis.

The contacts used were a needle-like contact with a conical tip and a
It is a flat contact with a carbon vapor deposition film of about 1,000 people.

The material of the needle contact is an alloy of iridium Ir and platinum Pt (
Vickers hardness Hv = 200 to 300 kg/mm), and the material of the flat contact is gold A11 (Vickers hardness Hy
=30-50 kg/mrtt).

In FIG. 3, the parameter is the contact force between both contacts.

Experimental results in the case where no carbon deposited film is attached to the flat contact are also shown for comparison.

From this figure, we can say the following.

When the apex angle 2α of the cone is small, the coating is almost destroyed and the resistance value becomes almost the same as in the case without the coating.

Further, in this case, the contact resistance was proportional to the first power of the contact force, and concentrated resistance was dominant.

When α is too small, the coating is not sufficiently destroyed and the contact resistance shifts to the coating resistance, and its absolute value also increases.

The smaller the tip angle α is, the more severe the mechanical failure of the coating is, but when considering the characteristics without a coating, it becomes clear that there is a tip angle α that minimizes the contact resistance, and in the case of a carbon coating, 2α is The contact resistance is at its minimum value near 90°.

For comparison, we conducted a contact experiment using a conventional hemispherical contact, but when there was a carbon coating, the contact force was 1 kg.
No electrical continuity was obtained either.

In addition, Fig. 3 shows the measurement results of the contact resistance value using a hemispherical contact when there is no carbon coating on the flat plate contact at the position of 2α = 180 degrees, but in this case, as a result of multiple measurements, Although variations are seen in the upper and lower ranges indicated by the arrows, the contact resistance shows a low value.

In other words, it can be seen that the hemispherical contact is effective for clean contacts that do not have a carbon film or the like, but is ineffective for contacts that have a carbon film or the like.

Figure 4 shows solder (38% tin S) used as a flat contact.
2 is a graph showing the relationship between the apex angle of a needle-like contact and the contact resistance when using lead (n and the remainder is lead (pb)).

In this case, an alloy of iridium Ir and platinum Pt was used as the material for the needle contacts, and the plate contacts were left indoors for 20 hours after polishing with alumina with a particle size of 0.3 μm. ing.

In this experiment, it was found that, except when using hemispherical contacts, the contact resistance was dominated by concentrated resistance, and the solder surface coating was mechanically destroyed.

As is clear from FIG. 4, when the solder was a flat contact, the minimum resistance value was obtained when the apex angle 2α was between 45° and 120°.

Even with materials whose coatings are said to be easily destroyed, such as solder, the use of needle-shaped contacts resulted in contact resistance values that were about an order of magnitude lower than those of hemispherical contacts.

An effective electrical connection can be achieved by pushing a relatively hard needle-like contact into a less hard plate-like contact, but electrical contact between dissimilar metals requires heat. It has been pointed out that there are problems such as sliding, contact potential difference, and promotion of chemical reactions due to differences in expansion coefficients.

Therefore, the base material of the needle-like contact is made of a harder material than that of the flat-plate contact, and by plating the surface of the needle-like contact with the same metal as the flat contact or a more effective metal, plastic deformation can be prevented. It is possible to construct a type of contact that depends on the hardness of the material and electrically on the metal applied to the surface.

If the material of the flat contact has a Vickers hardness of 50 kg/m4 or less or a Vickers hardness of H or less for the needle contact,
It is clear that the effects of the present invention can be obtained even if the material of the flat contact is applied to another base material by plating, for example.

Furthermore, good contact characteristics can be obtained by applying a different metal to the surface of the flat contact base material, which has a Vickers hardness of 50 kg/- or less, or H or less for needle contacts, even if it does not satisfy the above hardness. There is something to be gained.

Particularly, applying a metal (for example, tin) whose surface oxide film is easily destroyed to the surface of the flat contact has an important meaning in terms of contact resistance control due to the nature of the present invention.

According to the present invention, the following effects can be expected.

g) By adopting the configuration of the present invention, it is possible to efficiently destroy the coating on the surface of the contact and obtain electrical continuity.

Conventional connector contacts mainly use expensive gold as the contact material because the coating cannot be destroyed, but when the connector contacts of the present invention are applied, base metal contacts can be used and it has a great effect on making the connector economical.

(b) Since the needle-like contact is embedded in the flat-plate contact, the contact area is kept airtight from the surrounding deteriorating atmosphere, and high contact reliability can be expected.

(This also means that there is no need to use gold as a contact point, which contributes to the economicalization of connectors.

) (C) Compared to conventional connector contacts, which have a contact form of generally flat contacts, the present invention requires a lower contact force than conventional connector contacts because the contact force is concentrated at the tip of the needle-like contact. A large contact area can be obtained.

This is because stress is concentrated at the tip of the needle-like contact, which causes the actual contact area to be concentrated, making it less susceptible to the influence of the surrounding deteriorating atmosphere, making it possible to obtain sufficient contact reliability with low contact force. .

As described above, the present invention has a great effect on economicalization of connector contacts, and also has an excellent effect on reducing contact force, which becomes necessary as the density of connector terminals becomes higher.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the contact situation of a conventional contact, and FIGS. 3 and 4 are diagrams for explaining the effect of the contact according to the present invention even when it falls down. This is a graph obtained by actually measuring the relationship between the opening degree of the conical apex angle and the contact resistance of a conical needle-like contact. In the figure, 1 is a needle-like contact, 2 is a flat contact, 3 is a surface coating, and 4 is a hemispherical contact.

Claims (1)

[Claims] 1. Consisting of a needle-like contact and a flat plate-like contact facing each other,
In a connector contact which aims at electrical continuity between both contacts by pushing the needle-like contacts into the flat contact so as to push them into the flat contact, and furthermore, allows multiple connections and disconnections between the needle-like contact and the flat contact. , the apex angle of the tip of the needle contact is approximately 4
1. A connector contact, characterized in that the angle is in the range of 5 degrees to 120 degrees, and the hardness of the needle-like contact is four times or more that of the flat contact. 2. In the connector contact according to claim 1, the hardness of the needle contact is Vickers hardness of 200 kg/
− or more, and the hardness of the flat contact is Vickers hardness 5
A connector contact characterized by a combination of 0 kg/- or less. 3. The connector contact according to claim 1, characterized in that a layer of a different metal different from the base material is applied to the surface of at least one of the needle-like contact and the flat plate-like contact.