CN1241304C - Processing method for mounting connector on coaxial cable - Google Patents

Abstract

The invention relates to a processing method for assembling a connector on a coaxial cable, in which, by putting a sheath on each ground conductor to increase its outer diameter, the problems existing when the coaxial cable is assembled with a 2mmFB connector are solved The grounding conductor is easy to break the circuit; in addition, a φ1mm heat shrinkable sleeve is installed around the junction of the PE insulation and the PTFE insulation, and the PE insulation is installed on the outside of the covered wire when crimping, which solves the problem The PE insulation of the coaxial cable will damage the wire cover of the connecting terminal and the beam of the terminal plug; the foam insulation of the pico coaxial cable is peeled in an arc shape, which solves the problem that the micro coaxial cable is located at the two ends of the connector. The inner conductor on the side is easy to open circuit.

Description

Processing method for assembling connectors on coaxial cables

technical field

The present invention relates to cables used in communication products such as transmission, switching and access networks, and more specifically relates to a processing method for attaching connectors to coaxial cables.

Background technique

In transmission, switching, access network and other products, in order to transmit 2M E1 signal (E1 is the abbreviation of PCM30 in the digital system, it is a standard interface, its electrical interface conforms to G.703, and the frame structure conforms to G. 704, the code rate is PCM primary group, including a receiving line TX and sending line RX, the general transmission distance is several kilometers), generally using 2mmFB connector (also called FCI4*6 connector) and 75 ohm micro coaxial Cooperate with cables, or cooperate with 75 ohm pico-coaxial cables, both of these two methods can well meet the requirements of high-density outlets of current communication equipment in limited spaces.

1. Micro coaxial cable

The currently used 75-ohm micro-coaxial cable has a single-core structure and also has an 8-core structure. As shown in Figure 1, it is a schematic structural diagram of a single-core coaxial cable 1 with a model number of SFYZ-75-2-1 (A). From the outside to the inside, there are a single-core sheath 101, a single-core metal braid 102, and a grounding conductor 103. , PE insulation 104, F46 (polytetrafluoroethylene) insulation 105 and inner conductor 106. Wherein, the outer diameter of the single-core coaxial cable 1 is 2.7-2.9mm, the outer diameter of the PE insulation 104 is 1.35-1.55mm, and the outer diameter of the F46 insulation 105 is 0.55mm. As shown in Figure 2, it is a simplified structural diagram of the 8-core micro-coaxial cable 2 of the model SFYZ75-2-1*8(A), which is equivalent to packing 8 single-core micro-coaxial cables shown in Figure 1 into one package Together, a tear line 207, a mylar band 208 and an outer sheath 209 are added on the outside.

2. Pico coaxial cable

The currently used 75-ohm pico-coaxial cable only has an 8-core structure. As shown in Figure 3, it is a schematic structural diagram of a 75-ohm pico-coaxial cable with the model SFYFZ-75-2*8. It can be seen from the figure that for the Each single-core cable includes a grounding conductor 303 , a single-core metal braid 302 , foam insulation 304 , F46 insulation 305 and an inner conductor 306 from outside to inside. The outside is covered with a polyester tape 307, an inner sheath 308, a total metal braid 309 and an outer sheath 310, and a tear line 311 is also provided. It can be seen that the main difference between it and the micro-coaxial cable is that the total metal braid 309 is added as the total shielding layer, and the size of the wire core has changed. The outer diameter of a single wire core is 0.247-0.257mm, and the foam insulation 304 The outer diameter is 1.25-1.35mm, and the outer diameter of F46 insulation 305 is 0.55mm.

3. Connector

The currently commonly used 2mmFB connector has the advantages of high outlet density and reliable connection. Its structure is shown in Figure 4. The entire connector 4 is composed of two parts, a terminal plug 401 and a shell assembly 402 . As shown in FIG. 5 , it is an enlarged schematic view of a connecting terminal 404 taken out from the terminal plug 401 of the connector 4 , including terminal contacts 405 , front knife edge 406 , rear knife edge 407 and wire wrap 408 . As shown in FIG. 6 , it is a top view when the wire 5 is crimped in the terminal 404 . The specific crimping process is shown in FIG. 7 . During the crimping process, the front and rear knife edges can pierce the insulation of the wire and make contact with the internal conductor. After crimping, it is best if the insulation of the wire is located at the bottom of the terminal knife edge. If the wire position is too shallow, it may cause poor contact, and if it is too deep, it may cause wire fracture.

Fourth, the existing processing technology

The following describes the processing technology of micro-coaxial and pico-coaxial cables mated with 2mmFB connectors, including the following steps:

4-1 Cable off-line, stripping, and heat-shrinkable sleeve

For micro-coaxial cables and pico-coaxial cables, special wire strippers or coaxial cable stripping machines can be used to strip them according to the requirements of special process specifications and cable design drawings, and cover with heat-shrinkable sleeves 6 .

4-1-1 For the micro-coaxial cable, as shown in Figure 8, first strip off its single-core sheath 101 and single-core metal braid 102 to expose the grounding conductor 103, and then strip off a section of PE insulation to expose the F46 Insulate 105 the inner conductor.

4-1-2 For the pico coaxial cable, as shown in Figure 9, first strip off the outer sheath 310 and the overall metal braid 309 to expose the inner sheath 308; then peel off a section of the inner sheath 308 to expose the inner wire core; then peel off a section of the single-core braid 302 of each wire core, so that it has a certain distance from the root of the inner sheath; then strip off a section of the foam insulation 304, so that it has a certain distance from the root of the single-core braid , and finally expose the inner conductor with F46 insulation 305. In addition, a heat-shrinkable sleeve 6 is respectively sheathed on the outer sheath and the inner sheath of the cable.

4-2 suit case

As shown in FIG. 10, the housing assembly 402 of the connector 4 is pre-fitted on the cable.

4-3 Wire installation and crimping

The 2mmFB connector and the micro-coaxial cable or pico-coaxial cable are connected by a terminal crimping machine. During operation, fix the cable on the fixed table of the terminal crimping machine, and fix the wire core to be crimped above the terminal plug 401, and align it with the corresponding crimping position; start the terminal crimping machine to complete the single-sided crimping operation After that, crimp the other side. When crimping, the ground conductor and the inner conductor with F46 insulation are respectively pressed into the inner connecting terminal of the terminal plug 401, and the effect after crimping is shown in FIG. 11 .

4-4 final assembly

Push the prepackaged heat shrinkable sleeve to the root of the terminal plug 401, or use a heat gun to shrink it according to the requirements of the cable design drawing; then push the prepackaged connector shell assembly 402 to the terminal plug 401, and The terminal plug 401 is clamped, and the assembled product is shown in FIG. 12 .

Five disadvantages of prior art

Because the 28AWG-30AWG flat or twisted pair is most suitable for matching with the 2mmFB connector, there are the following problems when using this connector to cooperate with micro coaxial cable or pico coaxial cable:

5-1 For micro-coaxial cables and pico-coaxial cables, the diameter of the grounding conductor of each core is thinner, and there is no insulation layer, and the outer diameter is only 0.28mm. When it is crimped on the 2mmFB connector When connecting the terminal, since the minimum outer diameter of the wire core that can be compressed by the wire covering piece 408 in the connecting terminal 404 is 0.8 mm, which is much larger than the outer diameter of the grounding conductor, the wire covering piece does not play any fixing role after crimping. Once subjected to external force, it is easy to cause the grounding conductor to be disconnected here.

5-2 For micro-coaxial cables, during the crimping process of the inner conductor, as shown in Figure 13, it is necessary to press the PE insulation of the wire core with the wire covering sheet 408 to ensure that the wire covering sheet can compress the wire core. However, because the outer diameter of the PE insulation layer of the wire core is too large (1.35-1.55mm), it is easy to damage the wire cover sheet; at the same time, in order to ensure that the inner conductor of the wire core can be crimped in place, during the crimping process, the wire The PE insulation of the core is likely to crack the beam of the connector as indicated by the arrow in Figure 14.

5-3 For the pico coaxial cable, when it is attached to the connector, the stripping size of each single wire core in the prior art is the same (as shown in Figure 9), after being crimped into the terminal plug, due to the The stretching directions of the wire cores are different. As indicated by the arrows in Figure 15, the wire cores on both sides will have prestress. In the process of use, the bending of the cable will generate a certain external stress. The core may break or turn on and off due to force, resulting in equipment failure or unstable operation. According to the statistics currently used, about 15% of the cables processed by the above method have broken circuits, intermittent connections, and poor signal quality. Even cables that can be used normally temporarily have hidden dangers of poor contact. A current solution to the broken circuit is to weld the broken point, but it will cause the wire at the soldered point to be relatively brittle and hard, and it is still easy to break during use.

Contents of the invention

The present invention aims at the above defects existing in the existing processing technology, and provides a processing method for assembling a connector on a coaxial cable, so as to solve the problem that the grounding conductor is easily disconnected when the coaxial cable is connected to a 2mmFB connector, and at the same time It also solves the problem that the PE insulation of the micro-coaxial cable will damage the covered wire sheet of the connecting terminal and the crossbeam of the terminal plug, and the problem that the inner conductors on both sides of the connector in the pico-coaxial cable are easily disconnected.

The technical solution of the present invention lies in a processing method for assembling a connector on a coaxial cable, which is characterized in that it includes the following steps:

a. Take a section of coaxial cable, peel off its sheath until the inner grounding conductor and the inner conductor with PTFE insulation are exposed, and put a heat shrinkable sleeve on the cable sheath;

b. Treat the stripped cable, and put a sheath on each grounding conductor to increase its outer diameter;

c. Pre-set the shell assembly of the connector on the coaxial cable;

d. Crimp the ground conductor covered with wire sheath and the inner conductor with polytetrafluoroethylene insulation into the corresponding connection terminal in the terminal plug of the connector;

e. Adjusting the pre-packed heat-shrinkable sleeve, snapping the shell component pre-packed on the cable and the crimped terminal plug to complete the assembly process.

According to the method of the present invention, the connector in step c is a 2mmFB connector.

According to the method of the present invention, in the step b, the sheath sheathed on the ground conductor is the sheath of a subscriber cable with a specification of 28AWG-30AWG.

According to the method of the present invention, in the step a, for the pico coaxial cable, after stripping off the single-core braiding of each wire core in the cable to expose its foam insulation, the arc stripping method is used to strip The foam insulation of each wire core exposes the inner conductor with PTFE insulation, so that the cores on both sides of the terminal plug retain the longest foam insulation when crimping, and are located in the middle of the terminal plug when crimping The core of the core retains the shortest foam insulation. Wherein, the length of the core located in the middle from the foam insulation to its single-core braided root is 8-12 mm; The distance is more than 5mm longer than the reserved length of the core in the middle.

According to the method of the present invention, in the step b, for the micro-coaxial cable, a section of φ1mm heat-shrinkable sleeve is placed centering on the intersection of PE insulation and Teflon insulation, and the φ1mm heat-shrinkable sleeve is One part of the shrink sleeve is put on the PE insulation, and the other part is put on the Teflon insulation, and then it is blown with a heat gun. Correspondingly, in the step d, for the micro-coaxial cable, when crimping, the inner conductor with polytetrafluoroethylene is crimped at the front and rear knife edges of the connection terminal, and the inner conductor with polytetrafluoroethylene is crimped. A section of the ethylene inner conductor covered with the φ1mm heat-shrinkable sleeve is pressed into the wire-covered sheet of the connecting terminal.

By adopting a new processing technology, the invention can improve the reliability when the connector is assembled with the micro-coaxial cable and the pico-coaxial cable, greatly improve the electric performance and mechanical performance of the cable, and reduce the processing cost.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a structural schematic diagram of a single-core coaxial cable whose model is SFYZ-75-2-1 (A);

Figure 2 is a schematic structural diagram of an 8-core micro-coaxial cable of the model SFYZ75-2-1*8(A);

Figure 3 is a schematic structural diagram of a 75 ohm pico coaxial cable model SFYFZ-75-2*8;

Figure 4 is an exploded structure diagram of the 2mmFB connector;

Fig. 5 is an enlarged view of the connecting terminal with the terminal plug shown in Fig. 4 taken out;

Fig. 6 is a top view when connecting wires in the connecting terminal shown in Fig. 5;

Fig. 7 is A-A cross-sectional view of the crimping process of the wire and the connecting terminal shown in Fig. 6;

Figure 8 is a schematic diagram of the stripped micro-coaxial cable;

Fig. 9 is a schematic diagram of a pico-coaxial cable after stripping;

Fig. 10 is a schematic diagram of a housing assembly with a pre-installed connector;

Fig. 11 is a schematic diagram after the cable core is crimped to the terminal plug;

Figure 12 is a schematic diagram when the assembly is completed;

Fig. 13 is a schematic diagram of PE insulation covered by a wire-covered sheet in the prior art;

14 is an enlarged schematic view of a terminal plug of a connector;

Fig. 15 is a schematic diagram after the wire core of the pico coaxial cable is crimped to the terminal plug;

Fig. 16 is a schematic diagram of processing the peeled micro-coaxial cable in the method of the present invention;

Fig. 17 is a schematic diagram when the wire-wrapped sheet wraps the heat-shrinkable sleeve;

Fig. 18 is a schematic diagram of arc-shaped stripping of pico-coaxial cables in the present invention.

Detailed ways

Introduce below in the method of the present invention, the processing technology when micro-coaxial cable and pico-coaxial cable cooperate with 2mmFB connector, comprise the following steps:

6-1 Cable off-line, stripping, and heat-shrinkable sleeve

For micro-coaxial and pico-coaxial cables, special wire strippers or coaxial cable stripping machines can be used to strip them according to the requirements of special process specifications and cable design drawings, and set heat shrinkable sleeves 6:

6-1-1 For the micro-coaxial cable, as shown in Figure 8, first strip off its single-core sheath 101 and single-core metal braid 102 to expose the grounding conductor 103, and then strip off a section of PE insulation to expose the F46 Insulate 105 the inner conductor.

6-1-2 For the pico coaxial cable, as shown in Figure 18, first strip off the outer sheath 310 and the overall metal braid 309 to expose the inner sheath 308; then peel off a section of the inner sheath 308 to expose the inner wire core; then strip a section of the single-core braid 302 of each wire core so that there is a certain distance from the root of the inner sheath. After peeling off the single-core braid 302 of each wire core in the cable to expose its foam insulation, according to the present invention, the wire cores crimped on both sides of the pico coaxial cable during use are easy to break and sometimes on and off In this case, the foam insulation 304 is stripped by arc stripping, so that the cores located on both sides of the terminal plug during crimping retain the longest foam insulation, and the cores located in the middle of the terminal plug during crimping retain the longest foam insulation. The remaining foam insulation is the shortest, and the length difference between the longest and the shortest should be equal to or greater than 5mm. In addition, it is also necessary to have a heat-shrinkable sleeve 6 on the outer sheath and the inner sheath of the cable.

6-2 Crimp wire core processing

This is a newly added step of the present invention,

6-2-1 Grounding conductor set wire sheath

For micro-coaxial and pico-coaxial cables, put a user cable sheath of 28AWG-30AWG on each ground conductor. As shown in Figure 16, it is the case when the micro-coaxial cable is implemented. The outer diameter of this wire sheath 109 is about 0.8mm, and the minimum outer diameter of the wire core 408 in the connecting terminal 404 that can compress the core is 0.8mm. mm, it can be seen that the covered wire sheet can play a good role in fixing the grounding conductor covered with the 28AWG user cable sheath, and will not cause the grounding conductor to be disconnected at this place due to external force.

6-2-2 micro coaxial cable sleeve crimp heat shrinkable sleeve

For the coaxial cable, as shown in Figure 16, take a section of heat-shrinkable sleeve 108 with a diameter of 1 mm, and take the junction of PE insulation 104 and PTFE insulation 105 as the center, put one part on the PE insulation 104, and the other part on the PE insulation 104. on Teflon insulation 105, and blown it down with a heat gun.

6-3 suit case

As shown in FIG. 10, the housing assembly 402 of the connector 4 is pre-fitted on the cable.

6-4 Wire installation and crimping

In this step, the inner conductor of the micro-coaxial cable or the pico-coaxial cable is also pressed into the 2mmFB connector by the terminal crimping machine, but in the method of the present invention, due to the grounding of the micro-coaxial cable and the pico-coaxial cable The wire sheath of the user's cable has been set on the conductor, so what is crimped is the ground conductor with the wire sheath instead of the exposed ground conductor in the prior art; Heat-shrinkable sleeve, crimping First, crimp the inner conductor with polytetrafluoroethylene on the two knife edges of the connection terminal, and at the same time put the inner conductor with polytetrafluoroethylene covered with heat-shrinkable sleeve 108 A section is pressed into the wire-covered sheet 408, as shown in Figure 17, it can be seen that the PE insulation 104 is outside the wire-covered sheet but not inside the wire-covered sheet, and the outer diameter of the wire-covered sheet and the beam of the terminal plug is in contact with the smaller A section of the heat-shrinkable sleeve, thus solving the problem in the prior art that the PE insulation will damage the wire-covered sheet and the connector beam.

6-5 Final assembly

Push the prepackaged heat shrinkable sleeve to the root of the terminal plug 401, or use a heat gun to shrink it according to the requirements of the cable design drawing; then push the prepackaged connector shell assembly 402 to the terminal plug 401, and The terminal plug 401 is clamped, and the assembled product is shown in FIG. 12 .

It can be seen that the method of the present invention solves the problem that the ground conductor is easy to break when the coaxial cable is connected to the 2mmFB connector, and also solves the problem that the PE insulation of the micro-coaxial cable will damage the wire covering sheet of the connecting terminal and the crossbeam of the terminal plug problems, and the problem that the inner conductors located on both sides of the connector in pico-coaxial cables are prone to open circuits.

Claims (6)

1. A processing method for assembling a connector on a coaxial cable, comprising the following steps: a. Take a section of coaxial cable, peel off its sheath until the inner grounding conductor and the inner conductor with PTFE insulation are exposed, and put a heat shrinkable sleeve on the cable sheath; b. Treat the stripped cable, and put a sheath on each grounding conductor to increase its outer diameter; c. Pre-set the shell assembly of the connector on the coaxial cable; d. Crimp the ground conductor covered with wire sheath and the inner conductor with polytetrafluoroethylene insulation into the corresponding connection terminal in the terminal plug of the connector; e. Adjust the pre-set heat-shrinkable sleeve, and clamp the pre-set shell assembly on the cable with the crimped terminal plug to complete the assembly process; The connector in step c is a 2mmFB connector. 2. The method according to claim 1, characterized in that, in the step b, the sheath covered on the ground conductor is the sheath of a subscriber cable with a specification of 28AWG-30AWG. 3. The method according to claim 1, characterized in that, in the step a, for the pico coaxial cable, after stripping off the single-core braid of each wire core in the cable to expose its foam insulation, use The arc-shaped wire stripping method strips off the foam insulation of each wire core, exposing the inner conductor with PTFE insulation, so that the foam insulation retained by the wire cores on both sides of the terminal plug during crimping is the longest, while The cores in the middle of the terminal plug retain the shortest foam insulation when crimped. 4. The method according to claim 3, characterized in that, in the step a, the length of the core located in the middle from the foam insulation to the root of its single-core braiding is 8-12mm; The distance from the foam insulation to the root of the single-core braiding retained by the wire cores located on both sides is longer than the length retained by the wire cores located in the middle by more than 5mm. 5. The method according to claim 1, characterized in that, in the step b, for the micro-coaxial cable, a section of φ1mm heat-shrinkable As for the sleeve, one part of the φ1mm heat-shrinkable sleeve is put on the PE insulation, and the other part is put on the Teflon insulation, and then it is blown with a heat gun. 6. The method according to claim 5, characterized in that, in the step d, for the micro-coaxial cable, when crimping, the inner conductor with polytetrafluoroethylene is crimped on the connecting terminal At the front and rear knife edges, press a section of the φ1mm heat-shrinkable sleeve attached with a polytetrafluoroethylene inner conductor into the wire-covered sheet of the connecting terminal.

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