JP2014039359A - Power cable connection part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that heat is generated when a loop circuit including a conductor projection part, a tulip contact and a coming-off prevention cylindrical body is formed and a cyclic current is flown therein, in a power cable connection part comprising a male terminal 3 which is attached to an end of a conductor 1a of a power cable, a conductor projection part 7b which is a connection mate of the male terminal, a tulip contact 9 which electrically connects the conductor projection part and the male terminal and a metal coming-off prevention cylindrical body 19 which is arranged on the outer periphery from the tulip contact to the male terminal to prevent the tulip contact from opening when strong pull-out force over certain limit is applied to the power cable.SOLUTION: A part of the metal coming-off prevention cylindrical body 19 contacting the tulip contact 9 is constituted by an insulation body 21. The metal coming-off prevention cylindrical body 19 and the tulip contact 9 are insulated and flow of a cyclic current is stopped. Therefore heat generation can be prevented.

Description

  The present invention relates to a power cable connecting portion using a tulip contact for conductor connection.

  FIG. 3 shows a conventional power cable connection using a tulip contact. In the figure, 1 is a power cable (for example, a CV cable), 1a is a conductor of the power cable 1, 1b is also an insulator, and 3 is a male terminal attached to an end of the cable conductor 1a. Further, 5 is an epoxy unit that constitutes an insulator of the power cable connecting portion, 7 is a shielding electrode provided integrally inside the epoxy unit 5, and 9 is a tulip contact that electrically connects the shielding electrode 7 and the male terminal 3. , 11 is a stress cone pushed between the cable insulator 1b and the epoxy unit 5, and 13 is an annular stopper against which the tip of the stress cone 11 abuts.

  The male terminal 3 is formed by sequentially forming a contact contact portion 3b having a circular cross section, an annular protruding edge 3c, and a tapered portion 3d on the distal end side of the conductor crimping portion 3a. The shield electrode 7 has a hollow portion 7a that accommodates the male terminal 3, a conductor projection 7b having a circular cross section is formed on the inner wall of the cavity 7a, and an annular protruding edge at the tip of the conductor projection 7b. 7c is formed.

  The tulip contact 9 is formed by arranging a large number of strip-shaped conductor pieces 15 in a cylindrical shape and applying a tightening force by an annular coil spring 17 to the outer periphery of both ends. Each strip-shaped conductor piece 15 has an inward convex portion 15 a that contacts the contact contact portion 3 b of the male terminal 3 on one end side, and an inner surface that contacts the outer periphery of the conductor projection portion 7 b of the shielding electrode 7 on the other end side. The direction convex part 15b is formed.

  The tulip contact 9 is attached in advance to the conductor projection 7b of the shielding electrode 7. When the male terminal 3 is inserted into the cavity 7a of the shielding electrode 7, the inwardly convex portion 15a of each strip-shaped conductor piece 15 becomes the male terminal 3. After being pushed and widened by the tapered portion 3d and the annular projecting edge 3c, the diameter is reduced by the tightening force of the annular coil spring 17, and a connected state as shown in FIG. In this state, even if a pulling force is applied to the power cable 1, the inward convex portion 15a on one end side of the tulip contact 9 engages with the annular protruding edge 3c of the male terminal 3, and the inward convex portion 15b on the other end side. Engages with the annular projecting edge 7c of the conductor projecting portion 7b, and therefore cannot be pulled out easily. However, the male terminal 3 cannot be pulled out until the pulling force of the power cable 1 is up to about 100 kg. When the pulling force exceeds 100 kg, the force of the annular protruding edge 3c of the male terminal 3 to push one end of the tulip contact 9 is increased. There is a possibility that the male terminal 3 may be pulled out.

  In order to prevent this, a metal retaining cylinder 19 made of metal that prevents the tulip contact 9 from opening when a strong pulling force exceeding a certain limit is applied to the power cable 1 is incorporated in the power cable connecting portion. (See Patent Document 1). The retaining cylindrical body 19 is disposed on the outer periphery from the tulip contact 9 to the male terminal 3, and its proximal end side is fixed to the stopper 13 (may be formed integrally with the stopper 13), and the distal end side is the tulip contact 9. It is located on the outer periphery.

  With such a configuration, when the pulling force exceeding a certain limit is applied to the power cable 1 and one end side of the tulip contact 9 is likely to be expanded by the annular protruding edge 3c of the male terminal 3, the outer peripheral surface of the tulip contact 9 comes off. It strikes against the inner peripheral surface of the stop cylinder 19 and no longer opens. For this reason, the state in which the annular protruding edge 3c of the male terminal 3 and the inward protruding portion 15a of the tulip contact 9 are engaged (hooked) is maintained, and the tip of the male terminal 3 is prevented from being pulled out of the tulip contact 9. be able to. The reason why the retaining cylinder 19 is made of metal (copper or brass) is to ensure the mechanical strength necessary to prevent the tulip contact 9 from opening.

  The stopper cylinder 19 and the stopper 13 are retracted to a position where the tip of the stopper cylinder 19 does not cover the outer periphery of the tulip contact 9 when the tip of the male terminal 3 is inserted into the tulip contact 9. In addition, after the distal end portion of the male terminal 3 is inserted into the tulip contact 9, the distal end portion of the retaining cylindrical body 19 may be pushed into a position (the illustrated position) that covers the outer periphery of the tulip contact 9. The stress cone 11 is pushed into the epoxy unit 5 after the retaining cylinder 19 and the stopper 13 are pushed.

JP 2000-323198 A

  In the power cable connecting portion as shown in FIG. 3, a loop circuit is formed from the shielding electrode 7 through the conductor projection 7b-tulip contact 9-metal retaining cylinder 19-stopper 13 back to the shielding electrode 7. In such a case, the circulating current flows in the reverse direction, and the conductor connection portion may generate heat.

  In some cases, a gap is provided between the inner surface of the tip end of the metal retaining cylindrical body 19 and the outer peripheral surface of the tulip contact 9 (see Patent Document 1). In this case, the loop circuit as described above is not formed in a state where no pulling force is applied. However, when a strong pulling force is applied to the power cable and the one end side of the tulip contact 9 is opened and comes into contact with the inner surface of the metal retaining cylinder 19, the loop circuit as described above is formed, and there is a risk of heat generation. is there.

  In view of the above problems, an object of the present invention is to provide a power cable connecting portion in which the conductor connecting portion does not generate heat.

  In order to achieve the above object, the present invention provides a male terminal attached to an end of a conductor of a power cable, a conductor projection that is a connection partner of the male terminal, and electrically connecting the conductor projection and the male terminal. A tulip contact that connects to the metal terminal and a metal retaining cylinder that is placed on the outer periphery from the tulip contact to the male terminal and prevents the tulip contact from opening when a strong pulling force exceeding a certain limit is applied to the power cable. In the power cable connecting portion provided with a body, the portion of the retaining cylindrical body that is in contact with the tulip contact is made of an insulator.

  In the present invention, it is preferable that the tip of the retaining cylindrical body is also made of an insulator.

  According to the present invention, since the tulip contact and the metal retaining cylindrical body are electrically insulated, a loop circuit cannot be formed and the circulating current does not flow, so that heat generation can be prevented. Further, since the insulator is a part of the metal retaining cylinder, the mechanical strength required for the retaining cylinder can be sufficiently maintained.

  In addition, if the tip of the retaining cylinder is made of an insulating material as well as the portion of the retaining cylinder that contacts the tulip contact, the inner surface of the epoxy unit may be damaged when the retaining cylinder is incorporated into the epoxy unit. Disappear.

Sectional drawing which shows one Example of the power cable connection part which concerns on this invention. Sectional drawing which shows the other Example of the power cable connection part which concerns on this invention. Sectional drawing which shows an example of the conventional power cable connection part.

  Example 1 FIG. 1 shows an example of the present invention. In FIG. 1, the same parts as those in FIG. 3 described above are denoted by the same reference numerals, and redundant description is omitted.

  The feature of this power cable connecting portion is that the portion that contacts the tulip contact 9 of the metal retaining cylindrical body 19 is constituted by an insulator 21. As the insulator 21, it is preferable to use a plastic such as polyacetal.

  In this way, since the tulip contact 9 and the metal retaining cylinder 19 are insulated, a loop circuit cannot be formed and the circulating current does not flow, so that heat generation due to the circulating current can be prevented. Further, since the insulator 19 is a part of the metal retaining cylinder 19, the mechanical strength required for the metal retaining cylinder 19 can be sufficiently maintained.

  <Embodiment 2> FIG. 2 shows another embodiment of the present invention. In FIG. 2, the same parts as those in FIG. 3 described above are denoted by the same reference numerals, and redundant description is omitted.

  This power cable connecting portion is characterized in that not only the portion of the metal retaining cylinder 19 that contacts the tulip contact 9 but also the tip of the metal retaining cylinder 19 is made of an insulator 21. As the insulator 21, it is preferable to use a plastic such as polyacetal.

  If it does in this way, in addition to the effect similar to Example 1, when incorporating the metal retaining cylinder 19 into the epoxy unit 5, the tip of the metal retaining cylinder 19 may damage the inner surface of the epoxy unit 5. The effect of eliminating is obtained.

1: Power cable 1a: Cable conductor 1b: Cable insulator 3: Male terminal 3a: Conductor crimping part 3b: Contact contact part 3c: Annular protrusion 3d: Tapered part 5: Epoxy unit 7: Shielding electrode 7a: Cavity part 7b: Conductor projection 7c: annular protrusion 9: tulip contact 13: stopper 15: strip-shaped conductor piece 17: annular coil spring 19: metal retaining cylinder 21: insulator

Claims (2)

  A male terminal attached to the end of the conductor of the power cable, a conductor protrusion to which the male terminal is connected, a tulip contact for electrically connecting the conductor protrusion and the male terminal, and the tulip contact In the power cable connection portion provided with a metal retaining cylindrical body that is arranged on the outer periphery from the male terminal to the male terminal and prevents the tulip contact from opening when a strong pulling force exceeding a certain limit is applied to the power cable. A portion of the metal retaining cylindrical body that contacts the tulip contact is made of an insulator.   2. The power cable connecting portion according to claim 1, wherein the tip end portion of the metal retaining cylindrical body is also made of an insulator.

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