JP5634255B2 - Contact, contact manufacturing method, electrical connector - Google Patents

Description

  The present invention relates to a contact, a contact manufacturing method, and an electrical connector.

  As this type of technology, Patent Document 1 discloses a contact 52 including a contact bottom portion 50 and a contact spring portion 51 opposed to the contact bottom portion, as shown in FIG. The mating contact 53 inserted into the contact 52 is configured to come into contact with the contact bottom 50 and the contact spring 51 at three points.

JP 2004-281207 A

  In general, the above-mentioned contact is plated with tin or a tin alloy. However, such a contact is used in an environment where vibration (fine sliding) occurs, such as an in-vehicle connector. There is a problem that the contact resistance increases.

  An object of the present invention is to provide a contact with stable contact resistance in which an increase in contact resistance is suppressed.

  According to the first aspect of the present invention, the contact is made at three or more points of contact with the counterpart contact, and the contact mode at each contact is a spherical-to-plane contact. Contact radius a) × (Maximum contact pressure Pmax of Hertz) is substantially equal, and a contact is provided that contacts the counterpart contact with an odd number of contacts.
  An electrical connector with the above contacts is provided.
  According to a second aspect of the present invention, there is provided a contact manufacturing method in which contact is made with three or more points of contact with a counterpart contact, and the contact mode of each contact is spherical-to-plane contact. (Contact radius a of Hertz) × (maximum contact pressure Pmax of Hertz) is substantially equal, and the contact is contacted by an odd number of contacts with the counterpart contact.
  A contact manufactured by the above method is provided.
  An electrical connector with the above contacts is provided.

  According to the present invention, compared to the contact of Patent Document 1, an increase in contact resistance is suppressed, and a contact with stable contact resistance can be realized.

FIG. 1 is an exploded perspective view of a waterproof connector. FIG. 2 is a cross-sectional perspective view of the waterproof connector. FIG. 3 is a cross-sectional view of the contact. FIG. 4 is an explanatory diagram of the primary resistance peak. FIG. 5 is a first explanatory diagram of the problem of variation in contact resistance at the primary resistance peak. FIG. 6 is a second explanatory diagram of the problem of variation in contact resistance at the primary resistance peak. FIG. 7 is a graph showing the relationship between the contact resistance at the primary resistance peak and the contact load, which is a test result of the sliding test. FIG. 8 is a graph showing the relationship between the contact resistance at the primary resistance peak and (Hertz contact radius a) × (Hertz maximum contact pressure P _max ), which is a test result of the sliding test. FIG. 9 is a diagram in which the contact resistance is uniformized at the primary resistance peak. FIG. 10 is a diagram corresponding to FIG.

(Contact 7: FIGS. 1 to 3)
First, the contact 7 will be briefly described with reference to FIGS.

  A waterproof connector 1 (electric connector) shown in FIG. 1 is used for wiring of an electric system of, for example, a four-wheel vehicle or a two-wheel vehicle, and includes a front retainer 2, a sealing 3, a housing 4, and a grommet 5. The rear cover 6 and a plurality of contacts 7 (receptacle contacts, socket contacts) are provided as main components.

  The housing 4 holds a plurality of contacts 7. As shown in FIG. 2, the housing 4 houses a contact holding part 9 in which a cavity 8 into which the contact 7 can be inserted is formed, an outer cover 10 that surrounds the contact holding part 9 in an annular shape, a grommet 5 and a rear cover 6. And a housing main body 11. A sealing 3 is attached to the outer peripheral side of the contact holding portion 9, and a front retainer 2 shown in FIG. 1 is attached to the tip of the contact holding portion 9.

  As shown in FIGS. 1 and 2, the contact 7 is used by being attached to the end of the electric wire 12. A cross section of the contact 7 is shown in FIG. As shown in FIG. 3, in this embodiment, the contact 7 contacts the counterpart contact 13 at three contact points. Specifically, the contact 7 includes a contact bottom portion 7a and a leaf spring portion 7b facing the contact bottom portion 7a. Two dowel portions 7c are formed on the contact bottom portion 7a so as to protrude toward the leaf spring portion 7b. On the other hand, in the present embodiment, the mating contact 13 has a prismatic shape. With this configuration, when the mating contact 13 is inserted into the contact 7, the mating contact 13 is sandwiched between the leaf spring portion 7b and the two dowel portions 7c. In the present embodiment, the contact mode at each contact is spherical-to-plane contact. That is, a portion of the leaf spring portion 7b that contacts the mating contact 13 and a portion of each dowel portion 7c that contacts the mating contact 13 are spherical. Similarly, a portion of the mating contact 13 that contacts the leaf spring portion 7b and a portion of the mating contact 13 that contacts the dowel portion 7c are planar. Further, the contact load of the leaf spring portion 7b on the mating contact 13 is approximately twice the contact load of the single dowel portion 7c on the mating contact 13. In other words, the contact loads are not completely aligned at all the contacts.

  Further, the material of the contact 7 and the counterpart contact 13 is, for example, copper, and is subjected to tin plating for preventing corrosion.

(Primary resistance peak: Fig. 4)
Next, apart from the description relating to the contact 7, the primary resistance peak in the sliding test will be described with reference to FIG. FIG. 4 illustrates the transition of contact resistance between two metal parts. There is one contact between the two metal parts, and the contact mode at the contact is spherical-to-plane contact. The horizontal axis is the number of sliding between two metal parts, and the vertical axis is the contact resistance between the two metal parts. The two metal parts are both tin-plated copper.

  As shown in FIG. 4, when two metal parts are repeatedly slid, a phenomenon in which the contact resistance temporarily increases when the number of sliding times reaches several hundred to several thousand times. The cause of this phenomenon is generally considered as follows.

  That is, when two metal parts are repeatedly slid, tin-plated wear powder is generated. This wear powder becomes an oxidized wear powder exhibiting insulating properties. This oxidized wear powder is caught between two metal parts. This increases the contact resistance between the two metal parts. Eventually, oxidized wear powder caught between the two metal parts is eliminated. As a result, the contact resistance between the two metal parts decreases and stabilizes again.

  Hereinafter, in this specification, the peak of contact resistance in the above phenomenon is referred to as a primary resistance peak.

(Problems of contact resistance variation at the primary resistance peak: FIGS. 5-6)
Next, the problem of variation in contact resistance at the primary resistance peak will be described with reference to FIGS. Here, it is assumed that two metal parts are in contact with each other at three contacts, and the contact mode at each contact is spherical-to-plane contact. In FIGS. 5 to 6, the transition of the contact resistance at each contact is indicated by a solid line, a broken line, and a two-dot chain line. The contact resistance at the primary resistance peak at the contact indicated by the solid line is R1. Similarly, the contact resistance at the primary resistance peak at the contact indicated by the broken line is R2, and the contact resistance at the primary resistance peak at the contact indicated by the two-dot chain line is R3. In FIG. 5, R2 and R3 are substantially equal, and R1 is considerably smaller than R2 and R3. On the other hand, in FIG. 6, it is assumed that some problem occurs in the contact indicated by the solid line and the contact is in a substantially insulated state. Here, for convenience of explanation, in FIG. 5, R1 = R and R2 = R3 = kR (where k is k ≧ 1), and in FIG. 6, R1 = ∞ and R2 = R3 = kR. .

  In the state of FIG. 5, the contact resistance Rm5 between the two metal parts is obtained by the following formula (1).

  On the other hand, in the state of FIG. 6, the contact resistance Rm6 between the two metal parts is obtained by the following equation (2).

  Therefore, the following formula (3) is established.

  According to the above formula (1), it can be said that the larger k is, the contact resistance Rm5 between the two metal parts becomes almost equal to R1 regardless of the values of R2 and R3. In other words, the larger k is, the stronger R1 becomes dominant over the contact resistance Rm5 between the two metal parts.

  On the other hand, according to the above equation (3), if k is larger, if a problem occurs in the contact indicated by the solid line and the contact is in a substantially insulated state, the change width ΔR of the contact resistance between the two metal parts becomes smaller. It can be said that it will grow.

  By the way, in general, it is preferable that the contact resistance between two metal parts is stable without increasing or decreasing as much as possible. This design requirement is given priority over the magnitude of the contact resistance Rm5 between the two metal parts. Therefore, from this point of view, k is as small as possible, preferably k = 1. That is, it can be said that it is recommended that the contact resistance at the primary resistance peak at each contact is substantially equal to each other. However, knowledge about the contact resistance at the primary resistance peak at each contact is poor, and until now, the contact resistance at the primary resistance peak at each contact could not be made substantially equal.

(Dominant factors of contact resistance at the primary resistance peak at the contact: FIGS.
On the other hand, the inventor of the present application has determined that the dominant factors of the contact resistance at the primary resistance peak at each contact are as follows after extensive research.

  7 and 8 show test results of another sliding test. In this sliding test, two metal parts are brought into contact with each other with one contact. The contact mode at this contact is spherical-to-plane contact. In FIG. 7, the horizontal axis represents the contact load at the contact, and the vertical axis represents the contact resistance at the primary resistance peak at the contact. The triangle plot indicated by arrow A is the sliding test result when the curvature radius of the spherical surface is increased, and the circular plot indicated by arrow B is the sliding test result when the curvature radius of the spherical surface is decreased. According to FIG. 7, it can be seen that the larger the contact load, the smaller the contact resistance at the primary resistance peak at the contact point. However, it has been found that not only the contact load but also the radius of curvature is dominant in the contact resistance at the primary resistance peak at the contact point.

In contrast, in FIG. 8, after the twist and turn, the horizontal axis is (Hertz contact radius a) × (Hertz maximum contact pressure P _max ).

However, the Hertz contact radius a is obtained by the following equation (4), and the Hertz maximum contact pressure P _max is obtained by the following equation (5). In the following formulas (4) and (5), P is the contact load [N] at the contact, R is the radius of curvature [mm] of the spherical surface, and E ′ is obtained by the following formula (6). In the following formula (6), E ₁ is the Young's modulus [Pa] of the first metal part as one metal part, ν ₁ is the Poisson's ratio of the first metal part, and E ₂ is the other metal part. Is the Young's modulus [Pa] of the second metal part, and ν ₂ is the Poisson's ratio of the second metal part.

According to FIG. 8, it was found that the contact resistance at the primary resistance peak at the contact point can be estimated to some extent by considering the Hertz contact radius a and the Hertz maximum contact pressure P _max at the contact point. Specifically, according to FIG. 8, the contact resistance at the primary resistance peak at the contact point corresponds to (Hertz contact radius a) × (Hertz maximum contact pressure P _max ) on a one-to-one basis. I understand. That is, it can be said that the dominant factor of the contact resistance at the primary resistance peak at the contact is (Hertz contact radius a) × (Hertz maximum contact pressure P _max ).

Therefore, in order to make the contact resistance at the primary resistance peak at each contact substantially equal to each other, (Hertz contact radius a) × (Hertz maximum contact pressure P _max ) at each contact may be made substantially equal. It will be. In other words, the contact resistance at the primary resistance peak at each contact will be approximately equal to each other if (Hertz contact radius a) × (Hertz maximum contact pressure P _max ) at each contact is made substantially equal. become.

(Example: FIG. 9)
Based on the above considerations, the transition of contact resistance when (contact radius a of Hertz) × (maximum contact pressure P _{max of} Hertz) is substantially equal at each contact point between contact 7 and counterpart contact 13 shown in FIG. Is shown in FIG. In this way, by making (Hertz contact radius a) × (Hertz maximum contact pressure P _max ) substantially equal at each contact point between the contact 7 and the counterpart contact 13, contact at the primary resistance peak at each contact point. Resistance becomes substantially equal. That is, in FIG. 9, R1≈R2≈R3. Since the contact resistance at the primary resistance peak at each contact becomes substantially equal (that is, the variable k≈1 in the above formulas (1) to (3)), the contact at the primary resistance peak at any contact Even if the resistance is remarkably increased for some reason, the range that the contact resistance between the contact 7 and the counterpart contact 13 can take in the primary resistance peak can be narrowed based on the above formula (3). Since the possible range of contact resistance between the contact 7 and the counterpart contact 13 at the primary resistance peak is narrow, the contact resistance between the contact 7 and the counterpart contact 13 at the primary resistance peak is the configuration of Patent Document 1. It can be said that it is more stable than More simply, it can be said that according to the above configuration, the contact between the contact 7 and the counterpart contact 13 is stabilized.

  The preferred embodiment of the present invention has been described above. In short, the present embodiment has the following features.

That is, the contact 7 that contacts the counterpart contact 13 at three contact points, and the contact mode at each contact is a spherical-to-plane contact, the (contact radius a of Hertz) × (the maximum contact at Hertz) Pressure P _max ) is substantially equal. According to the above configuration, the contact resistance at the primary resistance peak at each contact is also substantially equal, and the contact resistance between the contact 7 and the counterpart contact 13 at the primary resistance peak is stabilized based on the above equation (3). .

Further, when the number of contacts between the contact 7 and the counterpart contact 13 is an odd number, there is a tendency that (Hertz contact radius a) × (Hertz maximum contact pressure P _max ) at each contact varies. Accordingly, when the number of contacts between the contact 7 and the counterpart contact 13 is an odd number, the above-described inventive concept exhibits a technical significance.

Further, according to FIG. 8, when designing and manufacturing the contact 7, taking into account (Hertz contact radius a) and (Hertz maximum contact pressure P _max ) itself is the primary resistance peak at each contact. It has an unprecedented technical significance in that the contact resistance can be estimated. And according to such knowledge, it can be said that a higher-performance contact can be realized as compared with the conventional product.

  Lastly, in the above embodiment, the number of contacts between the contact 7 and the counterpart contact 13 is three, but it may be four or five or more instead.

1 Waterproof connector (electrical connector)
2 Front retainer 3 Sealing 4 Housing 5 Grommet 6 Rear cover 7 Contact 7a Contact bottom 7b Leaf spring part 7c Dowel part 8 Cavity 9 Contact holding part 10 Outer cover 11 Housing body 12 Electric wire 13 Opposite contact

Claims (5)

Contact with the contact on the other side at three or more points, and the contact mode at each contact is a spherical to plane contact,
(Contact radius a of Hertz) × (maximum contact pressure Pmax of hertz) is substantially V equal at each contact,
Contact with the other contact at an odd number of contacts,
contact. An electrical connector comprising the contact according to claim 1 . A contact manufacturing method in which contact is made with three or more points of contact with the counterpart contact, and the contact mode at each contact is spherical-to-plane contact,
In each contact (contact radius a of Hertz) × (maximum contact pressure Pmax of hertz) substantially equal,
The contact contacts the counterpart contact at an odd number of contacts;
Contact manufacturing method. A contact manufactured by the method of claim 3 . An electrical connector comprising the contact according to claim 4 .

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