The following reasons have caused the connector connection to fail.
The inner conductor of the connector is smaller in size relative to the outer conductor, and the inner conductor having a lower strength is more likely to cause poor contact and cause the connector to fail.
Most of the inner conductors of the connector are elastically connected, for example, a spring claw type elastic connection, a jack slot type elastic connection, a bellows type elastic connection, and the like. The jack slot type elastic connection structure is simple, the processing cost is low, the assembly is convenient, and the application range is the most extensive.
1, the inner conductor is not fixed firmly
For assembly purposes, in many RF coaxial connectors (eg, N-type, 3.5 mm), the inner conductor is divided into two sections at the media support and then threaded. However, due to the small diameter of the inner conductor, if the glue is not fixed at the screw connection during assembly, the strength of the inner conductor connection is very poor, especially for some small RF coaxial connectors. Therefore, when the connector is connected and disconnected multiple times, under the long-term action of the torque and the pulling force, the inner conductor thread may loosen and fall off, resulting in the connection failure.
One of the commonly used structures of RF coaxial connectors is that the inner conductor, the dielectric support, and the outer conductor are held together by means of an adhesive. If the structure is insufficient in the assembly or the connection strength of the glue is insufficient, the glue may be broken due to the force during use, which may cause the inner conductor to rotate or axially move, and between the inner conductors. Failure to form a good electrical contact and failure of the connection.
Improved method: When the coaxial connector is assembled, apply a proper amount of conductive glue or thread locker at the threaded joint to increase the reliability of the threaded connection. It is necessary to use an adhesive with high bonding strength, and it is necessary to ensure that the glue fills the entire coating hole when the glue is applied; the inner conductor is knurled, the contact area between the inner conductor and the adhesive is increased, and the inner conductor is prevented from rotating; The radial dimension and tolerance of the conductor, the outer conductor and the medium support make the inner conductor and the medium support, the medium support and the outer conductor have an interference fit, and the three can be assembled more firmly.
2. The size of the inner conductor's jack or pin is incorrect.
If the inner conductor hole diameter of the jack is smaller than the specified size, when the pin of the inner conductor of the pin enters the jack, the jack is excessively expanded, and the shape variable exceeds the elastic deformation range, causing plastic deformation, resulting in damage of the inner conductor of the jack; On the contrary, if the diameter of the pin is too small, when the pin and the socket are engaged, the gap between the pin and the wall of the jack is too large, the two inner conductors of the connector are not in close contact, the contact resistance becomes large, and the connector is Electrical performance indicators will also be poor.
Improvement method: Whether the socket and the pin are properly matched, we can measure the insertion force and the holding force when the standard gauge pin and the inner conductor of the jack are matched. For the N-type connector, the insertion force of the diameter Φ1.6760+0.005 standard gauge pin and the socket should be ≤9N, and the retaining force when the diameter Φ1.6000-0.005 standard gauge pin and the inner conductor of the jack are matched ≥0.56N. Therefore, we can use the insertion force and the holding force as a test standard to adjust the insertion and force between the pin and the socket by adjusting the size and tolerance of the jack and the pin, and the aging process of the inner conductor of the jack. In a suitable range.