Power cable terminal connection part and method for manufacturing the same

Abstract

To provide a power cable termination connection portion with high workability during manufacturing, and a manufacturing method thereof.SOLUTION: A power cable termination connection portion 2 to which a termination portion of a power cable 1 is connected includes: a cable holder 3 having an insertion hole 20 into which a central conductor 11 and an insulating layer 12 of the power cable 1 are inserted; and a metal tubular member 4 fixed to the end of the cable holder 3 and housing parts of a shielding layer 13 and a sheath 14, The cable holder 3 includes: an insulator 30 made of a polymer-based material; and semi-conductors 31 to 33 made of a polymer-based material to which conductivity is imparted by a conductivity-imparting agent. The tubular member 4 includes an embedded portion 41 embedded in the cable holder 3, and a cylindrical portion 42 exposed from the cable holder 3. The cylindrical portion 42 has an annular stepped portion 423 formed on an inner peripheral surface 42a, and the inner diameter of the portion closer to the embedded portion 41 than the stepped portion 423 is smaller than that of on the side opposite to the embedded portion 41 relative to the stepped portion 423.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power cable end connection part to which the end part of a stepped-peeled power cable is connected, and a method for manufacturing the same.

Background Art

[0002] Conventionally, as a polymer connection part for a power cable applied to devices such as transformers and gas-insulated switches, the applicant has proposed the one disclosed in Patent Document 1. This polymer connection part for a power cable mainly includes a polymer protection layer formed of a polymer-based material and having a cable insertion hole into which the end part of the power cable is inserted, an insulating plug that connects a compression terminal connected to the conductor of the power cable to the device-side conductor of the device, and a waterproof treatment part that seals the rear end side of the polymer protection layer. The polymer protection layer includes an insulator formed of a polymer-based material, first and second semiconductive parts that relax the electric field of the power cable, a protection cover that protects the tip side of the insulator, and a metal tubular member provided on the rear end side of the insulator. The insulator, the first and second semiconductive parts, the protection cover, and the tubular member are integrally formed by molding. The waterproof treatment part is formed by winding a waterproof tape with an adhesive layer around the outer periphery of the tubular member and the sheath of the power cable, and covering it with a heat-shrinkable tube thereon. Since the adhesiveness of the waterproof tape to the tubular member is better than that to the insulator of the polymer protection layer, it is possible to surely perform the waterproof treatment.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of connecting a ground wire to a tubular member with a bolt and electrically grounding it as described in Patent Document 1, it is necessary to increase the thickness of the tubular member. In this case, the rigidity of the tubular member increases, and when integrally molding the polymer protective layer by molding, it becomes difficult to insert and remove the mold member disposed inside the tubular member with respect to the tubular member, resulting in a decrease in workability. Further, when the outer diameter is reduced so that the mold member can be easily inserted and removed with respect to the tubular member, the molten polymer material leaks out from the gap between the mold member and the tubular member.

[0005] Therefore, an object of the present invention is to provide a power cable terminal connection portion having high workability during manufacturing and a method for manufacturing the same.

Means for Solving the Problems

[0006] The present invention aims to solve the above problems, and includes a center conductor, an insulating layer covering the outer periphery of the center conductor, a shielding layer composed of a plurality of shield wires arranged so as to surround the outer periphery of the insulating layer, and a sheath covering the outer periphery of the shielding layer. A power cable terminal connection portion to which a terminal portion of a power cable is connected, the power cable terminal connection portion having a cable holder having an insertion hole into which the center conductor and the insulating layer of the power cable are inserted, and fixed to an end of the cable holder, and inserting the center conductor and the insulating layer and accommodating a part of the shielding layer and the sheath. A metal tubular member, the cable holder having an insulator formed of a polymer-based material and a semiconductor formed of a polymer-based material having conductivity imparted by a conductivity-imparting agent, the tubular member having an embedded portion embedded in the cable holder and a cylindrical portion exposed from the cable holder, the embedded portion and the cylindrical portion being arranged in an axial direction along the longitudinal direction of the power cable, the cylindrical portion having an annular step portion formed on an inner peripheral surface, and an inner diameter of a portion on the embedded portion side of the step portion being smaller than an inner diameter of a portion on the side opposite to the embedded portion of the step portion. A power cable terminal connection portion is provided.

[0007] Further, the present invention is a manufacturing method for manufacturing the above-described power cable terminal connection portion, which aims to solve the above problems, and has an insulator molding step of injection molding the insulator of the cable holder using a rod-shaped member inserted inside the tubular member. The rod-shaped member has an annular groove formed on the outer peripheral surface of a portion disposed on the embedding portion side rather than the stepped portion in the insulator molding step, and an annular elastic body is accommodated in the annular groove. The elastic body elastically contacts the inner peripheral surface of the cylindrical portion on the embedding portion side rather than the stepped portion, and provides a manufacturing method for a power cable terminal connection portion.

Advantages of the Invention

[0008] According to the power cable terminal connection portion and its manufacturing method according to the present invention, the workability during the manufacture of the power cable terminal connection portion can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] [Embodiment] The power cable terminal connection part and its manufacturing method according to the embodiment of the present invention will be described with reference to Figs. 1 to 9. Fig. 1 is a cross-sectional view specifically showing an example of a power cable connection structure including the power cable terminal connection part according to the embodiment of the present invention. Fig. 2 is a cross-sectional view of the power cable taken along line A-A of Fig. 1. This power cable connection structure is a connection structure for connecting a power cable 1 for transmitting high-voltage power to a power cable terminal connection part 2 provided, for example, under the floor of a railway vehicle.

[0011] (Configuration of Power Cable 1 and Power Cable Terminal Connection Part 2) As shown in Fig. 2, the power cable 1 has a center conductor 11 formed by twisting a plurality of stranded wires 111, an insulating layer 12 covering the outer periphery of the center conductor 11, a shielding layer 13 composed of a plurality of shield wires 131 arranged so as to surround the outer periphery of the insulating layer 12, and a sheath 14 covering the outer periphery of the shielding layer 13. In the present embodiment, an internal semiconductive layer 15 is provided between the center conductor 11 and the insulating layer 12, and an external semiconductive layer 16 is provided between the insulating layer 12 and the shielding layer 13. A holding tape 17 is spirally wound around the outer periphery of the shielding layer 13, and the outside thereof is covered with the sheath 14.

[0012] As the strands 111 of the center conductor 11, for example, wire rods made of highly conductive metals such as tinned soft copper wires can be used. The center conductor 11 transmits, for example, a high voltage of 7000V or more. The insulating layer 12 is formed, for example, by extrusion molding materials such as ethylene propylene rubber, vinyl chloride, crosslinked polyethylene, silicone rubber, and fluorine-based materials. The sheath 14 is formed, for example, by extrusion molding rubber such as natural rubber, butyl rubber, halogenated butyl rubber, and non-halogen polyolefin elastomer to which a crosslinking agent and the like are added. The shield wire 131 is made of, for example, a wire rod such as a tinned soft copper wire and is wound horizontally in a spiral shape.

[0013] The inner semiconductive layer 15 and the outer semiconductive layer 16 are provided to relieve the concentration of the electric field, are mainly formed of polymer-based materials, and are formed by extrusion molding materials in which conductive powder is dispersed to have conductivity. As the pressing tape 17, for example, a strip made of plastic or rayon can be used.

[0014] At the terminal portion of the power cable 1 connected to the power cable terminal connection portion 2, the outer sheath is step-peeled, and each layer is exposed step by step. Specifically, a part of the sheath 14 and the pressing tape 17 is removed to expose a plurality of shield wires 131, a part of the outer semiconductive layer 16 is removed to expose the insulating layer 12, and further a part of the insulating layer 12 and the inner semiconductive layer 15 is removed to expose the center conductor 11.

[0015] A compression terminal 10 is attached to the center conductor 11 exposed from the insulating layer 12. The compression terminal 10 has a cylindrical clamping portion 101 clamped so as to compress the center conductor 11 and a flat connection portion 102 provided integrally with the clamping portion 101. An accommodation hole 101a for accommodating the center conductor 11 is formed in the clamping portion 101. A device connection hole 102a is formed at the tip of the connection portion 102.

[0016] The connection part 102 of the compression terminal 10 is connected to the device-side conductor 91 of the device 9 to be connected by a nut 100 inside the power cable end connection part 2. The device 9 has a tapered device-side bushing 90 and a device-side conductor 91 exposed from the device-side bushing 90. A male thread 91a is formed at the tip of the device-side conductor 91.

[0017] The power cable end connection part 2 includes a cable holder 3 provided with an insertion hole 20 into which the center conductor 11 and the insulating layer 12 of the power cable 1 are inserted, a metal tubular member 4 fixed to the end of the cable holder 3, a waterproof treatment part 5 for preventing water from entering the inside of the tubular member 4, an insulating plug 61 for connecting the compression terminal 10 to the device-side conductor 91 of the device 9, and a protective cap 62 for protecting the insulating plug 61.

[0018] The waterproof treatment part 5 is formed by winding a strip-shaped member with good water resistance, such as a waterproof tape 51 like a polyethylene tape with an adhesive layer or an epoxy tape, around the outer periphery of the tubular member 4 and the sheath 14 multiple times, and further covering the waterproof tape 51 with a heat shrinkable tube 52. Note that the waterproof treatment part 5 is not limited to the one using the waterproof tape 51 and the heat shrinkable tube 52, and other structures may be used.

[0019] The insulating plug 61 includes a molded insulator 611, a high-voltage electrode 612 provided at one end of the insulator 611, and a detection electrode 613 provided at the other end of the insulator 611. The high-voltage electrode 612 is formed with a counterbore 612a corresponding to the shape of the nut 100 and a female thread 612b into which the male thread 91a provided on the device-side conductor 91 is screwed. The detection electrode 613 is formed with a tool fitting hole 613a into which the tip of a tool such as a socket wrench is fitted. The insulator 611 is integrally molded with the high-voltage electrode 612 and the detection electrode 613.

[0020] The protective cap 62 is made of a semiconductive rubber material and is formed in a bottomed cylindrical shape having an integral disc-shaped bottom wall 621 and a cylindrical side wall 622. The bottom wall 621 covers the insulating plug 61. An annular convex portion 622a for fixing to the cable holder 3 is formed on the inner peripheral surface of the side wall 622.

[0021] The cable holder 3 is provided with an insertion hole 20 at the center, and has a holding cylinder portion 3A that holds the center conductor 11 and the insulating layer 12 of the power cable 1, and a connection cylinder portion 3B that houses the connection portion between the compression terminal 10 and the device-side conductor 91 of the device 9. In the present embodiment, the axial direction of the connection cylinder portion 3B is perpendicular to the axial direction of the holding cylinder portion 3A, and the cable holder 3 is formed in a T shape. Hereinafter, in the axial direction of the holding cylinder portion 3A (the left-right direction in FIG. 1), the side of the connection cylinder portion 3B is referred to as the front end side, and the opposite side (the side of the tubular member 4) is referred to as the rear end side.

[0022] The cable holder 3 has an insulator 30 formed of a polymer-based material and first to third semiconductors 31 to 33 formed of a polymer-based material to which conductivity is imparted by dispersing a conductivity-imparting agent. The insulator 30 is provided over the holding cylinder portion 3A and the connection cylinder portion 3B, and is provided around the insertion hole 20 in the holding cylinder portion 3A. Further, in the insulator 30 in the connection cylinder portion 3B, a bushing insertion hole 301 into which the device-side bushing 90 is inserted and an insulating plug insertion hole 302 into which the insulating plug 61 is inserted are formed. The first to third semiconductors 31 to 33 are provided integrally with the insulator 30 and relax the electric field around the power cable 1. Further, the third semiconductor 33 has a shielding function of suppressing leakage of the electric field around the power cable 1 to the outside.

[0023] As the polymer-based materials of the insulator 30 and the first to third semiconductors 31 to 33 in the cable holder 3, for example, silicone rubber, ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), etc. can be used. As the conductivity-imparting agent, for example, conductive fine powder such as carbon black can be used.

[0024] The first to third semiconductors 31 to 33 are molded bodies injection-molded in advance prior to forming the insulator 30. The first semiconductor 31 surrounds the compression terminal 10 from the end on the tip side to the connection cylinder portion 3B in the holding cylinder portion 3A. In the first semiconductor 31, a terminal insertion hole 311 into which the compression terminal 10 is inserted together with a part of the longitudinal direction of the central conductor 11 and the insulating layer 12, and a housing hole 312 for housing a part of each of the device-side bushing 90 and the insulating plug 61 are formed. The second semiconductor 32 is disposed on the rear end side of the holding cylinder portion 3A with respect to the first semiconductor 31.

[0025] The insertion hole 20 is formed by a small-diameter hole portion 21 having an inner diameter corresponding to the outer diameter of the insulating layer 12 of the power cable 1, a large-diameter hole portion 23 provided at the end on the rear end side, and a tapered hole portion 22 whose inner diameter gradually increases from the small-diameter hole portion 21 toward the large-diameter hole portion 23. A part of the small-diameter hole portion 21 on the tip side is formed by the first semiconductor 31, and a part of the small-diameter hole portion 21 on the rear end side is formed by the second semiconductor 32. Between the first semiconductor 31 and the second semiconductor 32, the small-diameter hole portion 21 is formed by the insulator 30. The manufacturing method of the cable holder 3 will be described later.

[0026] FIG. 3(a) is a side view of the third semiconductor 33 as viewed from a direction perpendicular to the axial direction of the holding cylinder portion 3A and the axial direction of the connection cylinder portion 3B, and FIG. 3(b) is a side view of the third semiconductor 33 as viewed from the rear end side along the axial direction of the holding cylinder portion 3A. In FIGS. 3(a) and 3(b), the ground wire 71 is shown together with the third semiconductor 33.

[0027] The third semiconductor 33 integrally has a cylindrical portion 331 that covers the insulator 30 around the insertion hole 20 in a part on the tip side of the holding cylinder portion 3A including the outer periphery of the first semiconductor 31, first and second protruding pieces 332 and 333 protruding radially outward from the outer peripheral surface 331a of the cylindrical portion 331, and an outer shell portion 334 that constitutes the outer outline of the connection cylinder portion 3B. The outer shell portion 334 is formed in a cylindrical shape so as to cover the insulator 30 in the connection cylinder portion 3B. An annular concave portion 334a with which a convex portion 622a formed on the side wall 622 of the protective cap 62 engages is formed on the outer peripheral surface 334b of the outer shell portion 334.

[0028] The first protruding piece portion 332 and the second protruding piece portion 333 are provided at symmetric positions sandwiching the insertion hole 20. That is, the first and second protruding piece portions 332, 333 are provided at positions separated by 180° in the circumferential direction of the cylindrical portion 331. A through hole 332a penetrating the first protruding piece portion 332 is formed in the first protruding piece portion 332. Further, a through hole 333a penetrating the second protruding piece portion 333 is formed in the second protruding piece portion 333.

[0029] In the present embodiment, when viewed from a direction perpendicular to the axial direction of the holding cylinder portion 3A and the axial direction of the connection cylinder portion 3B of the third semiconductor 33, the first and second protruding piece portions 332, 333 are formed in a triangular shape. However, the shapes of the first and second protruding piece portions 332, 333 are not limited to this, and may be, for example, a quadrangular shape or a semi-circular shape.

[0030] An earth wire 71 is connected to the first protruding piece portion 332. The earth wire 71 has an earth wire main body 711 made of an insulated electric wire whose core wire is covered with an insulator, and an earth terminal 712 attached to the tip of the earth wire main body 711. The earth terminal 712 is attached to the first protruding piece portion 332 by a bolt 72 and a nut 73. The threaded portion 721 of the bolt 72 is inserted into the through hole 332a of the first protruding piece portion 332.

[0031] Note that the earth wire 71 may be connected to the second protruding piece portion 333. In this case, the threaded portion 721 of the bolt 72 is inserted into the through hole 333a of the second protruding piece portion 333. Further, when the earth wire 71 is connected to the first protruding piece portion 332, the through hole 333a does not have to be formed in the second protruding piece portion 333, and when the earth wire 71 is connected to the second protruding piece portion 333, the through hole 332a does not have to be formed in the first protruding piece portion 332. That is, it is sufficient that a through hole penetrating the corresponding protruding piece portion is formed in at least one of the first and second protruding piece portions 332, 333.

[0032] The tubular member 4 is fixed to the end on the rear end side of the cable holder 3, allows the central conductor 11 and the insulating layer 12 of the power cable 1 to pass through, and accommodates a part of the shielding layer 13 and the sheath 14. The tubular member 4 is made of a metal having high conductivity such as brass or aluminum alloy. A plurality of shield wires 131 of the shielding layer 13 are led out from the sheath 14 inside the tubular member 4, folded back to the outer periphery of the sheath 14, and led out to the outside of the tubular member 4 from between the outer peripheral surface 14a of the sheath 14 and the inner peripheral surface 4a of the tubular member 4.

[0033] Fig. 4(a) is a perspective view showing the tubular member 4. Fig. 4(b) is a perspective cross-sectional view of the tubular member 4 taken along line B-B in Fig. 4(a). The tubular member 4 integrally has an embedded portion 41 embedded in the cable holder 3 and a cylindrical portion 42 exposed from the cable holder 3. The tubular member 4 is fixed to the cable holder 3 by embedding the embedded portion 41 in the insulator 30 of the cable holder 3.

[0034] The embedded portion 41 is cylindrical, and through holes 410 penetrating the embedded portion 41 in the axial direction are formed at a plurality of locations in the circumferential direction (four locations in the present embodiment). The insulator 30 has entered the plurality of through holes 410. The embedded portion 41 is embedded in the insulator 30 of a part of the tapered hole portion 22 of the insertion hole 20 and a portion corresponding to the outer peripheral side of the large-diameter hole portion 23.

[0035] The embedded portion 41 and the cylindrical portion 42 are arranged in the axial direction along the longitudinal direction of the power cable 1 inside the tubular member 4. The cylindrical portion 42 further has a large-diameter portion 421 and a small-diameter portion 422 having different outer diameters. The large-diameter portion 421 is formed continuously with the embedded portion 41. The small-diameter portion 422 has an outer diameter smaller than that of the large-diameter portion 421 and is formed continuously with the end portion of the large-diameter portion 421 on the side opposite to the embedded portion 41. The waterproof tape 51 of the waterproof treatment portion 5 is wound around the outer peripheral surface 422a of the small-diameter portion 422.

[0036] The embedded portion 41 is formed with an outer diameter smaller than that of the large-diameter portion 421 and the small-diameter portion 422. Also, the embedded portion 41 is formed with a thickness in the radial direction thinner than that of the large-diameter portion 421 and the small-diameter portion 422. The outer peripheral surface 421a of the large-diameter portion 421 is not covered by the insulator 30 of the cable holder 3 and is exposed to the outside. The insulator 30 of the cable holder 3 is in close contact with the outer peripheral surface 41a of the embedded portion 41 and the axial end surface 421b of the large-diameter portion 421 on the side of the embedded portion 41.

[0037] Also, the tubular member 4 is provided with a ground wire connection portion 401 to which a ground wire 74 is connected and a shield wire connection portion 402 to which a plurality of shield wires 131 are connected on the cylindrical portion 42. The ground wire connection portion 401 is provided at a portion not covered by the waterproof treatment portion 5, and the shield wire connection portion 402 is provided at a portion covered by the waterproof treatment portion 5. In the present embodiment, the ground wire connection portion 401 is provided at one location in the circumferential direction of the large-diameter portion 421, and the shield wire connection portions 402 are provided at a plurality of locations in the circumferential direction of the small-diameter portion 422. The ground wire connection portion 401 is a part of the large-diameter portion 421, and the shield wire connection portion 402 is a part of the small-diameter portion 422.

[0038] Connection terminals 75 are attached to the tip ends of the plurality of shield wires 131. In the present embodiment, the number of shield wires 131 in the shielding layer 13 is 20, and these 20 shield wires 131 are electrically connected to the tubular member 4 by two connection terminals 75, ten by ten. That is, in the present embodiment, two shield wire connection portions 402 are provided on the tubular member 4, and these shield wire connection portions 402 are provided at positions 180° apart in the circumferential direction of the small-diameter portion 422. The waterproof treatment portion 5 covers the 20 shield wires 131 led out from the tubular member 4 together with the two connection terminals 75.

[0039] The two connection terminals 75 are each connected to the shield wire connection part 402 by bolts 76. The shield wire connection part 402 is formed with a screw hole 402a into which the bolt 76 for connecting the connection terminal 75 is screwed. In the present embodiment, the screw hole 402a penetrates the small diameter part 422 in the radial direction. However, the screw hole 402a does not necessarily have to penetrate the small diameter part 422. The peripheral part of the opening of the screw hole 402a on the outer peripheral surface 422a of the small diameter part 422 is a flat surface 402b perpendicular to the central axis of the screw hole 402a so that the connection terminal 75 can be securely connected by tightening the bolt 76.

[0040] The ground wire 74 includes a ground wire main body 741 made of an insulated electric wire whose core wire is covered with an insulator, and a ground terminal 742 attached to the tip of the ground wire main body 741. A screw hole 401a into which a bolt 77 for connecting the ground terminal 742 is screwed is formed to open on the outer peripheral surface 421a of the large diameter part 421 of the tubular member 4 and does not penetrate the tubular member 4. The peripheral part of the opening of the screw hole 401a on the outer peripheral surface 421a of the large diameter part 421 is a flat surface 401b perpendicular to the central axis of the screw hole 401a so that the ground terminal 742 can be securely connected by tightening the bolt 77.

[0041] As shown in FIG. 4(b), the thickness T1 of the embedded part 41 in the radial direction of the tubular member 4 is thinner than the thickness T2 of the ground wire connection part 401 in the radial direction of the tubular member 4. Here, the thickness T2 of the ground wire connection part 401 is the distance between the flat surface 401b in the central axis direction of the screw hole 401a and the inner peripheral surface 4a of the tubular member 4. Also, the thickness T1 of the embedded part 41 is thinner than the thickness T3 of the shield wire connection part 402 in the radial direction of the tubular member 4. Here, the thickness T3 of the shield wire connection part 402 is the distance between the flat surface 402b in the central axis direction of the screw hole 402a and the inner peripheral surface 4a of the tubular member 4. The thickness T1 of the embedded part 41 is, for example, 1 / 2 or less of the thickness T2 of the ground wire connection part 401. The thickness T1 of the embedded part 41 is, for example, 4 to 5 mm, and the thickness T2 of the ground wire connection part 401 is, for example, 15 mm.

[0042] (Manufacturing Method of Power Cable Terminal Connection Port 2 and Cable Holder 3) Next, a manufacturing method of the power cable terminal connection port 2 and the cable holder 3 will be described with reference to FIGS. 5 to 9. This manufacturing method includes a semiconductor molding step of molding the first to third semiconductors 31 to 33, an arranging step of arranging the first to third semiconductors 31 to 33 and the tubular member 4 in a mold, and an insulator molding step of injecting a thermoplastic polymer material into the mold to mold the insulator 30. In the semiconductor molding step, each of the first to third semiconductors 31 to 33 is injection molded by injecting a thermoplastic polymer material having conductivity with conductive powder dispersed therein into the mold.

[0043] FIG. 5 is an explanatory diagram showing the mold 8 for molding the insulator 30 together with the third semiconductor 33. The mold 8 includes an upper mold 81 and a lower mold 82, first and second columnar molds 83 and 84, and a rod-shaped mold 85 which is a rod-shaped mold member for forming the insertion hole 20. The first and second columnar molds 83 and 84 and the rod-shaped mold 85 can move forward and backward in a direction perpendicular to the relative movement direction of the upper mold 81 and the lower mold 82.

[0044] As an example, the lower mold 82 is fixed to the mold base, and the upper mold 81 moves up and down in the vertical direction with respect to the lower mold 82. The first and second columnar molds 83 and 84 and the rod-shaped mold 85 move forward and backward in the horizontal direction with respect to the lower mold 82. The first columnar mold 83 and the second columnar mold 84 move along the central axis direction so as to approach and separate from each other, and the rod-shaped mold 85 moves in a direction perpendicular to the central axes of the first and second columnar molds 83 and 84.

[0045] FIG. 6 is an explanatory diagram showing the first to third semiconductors 31 to 33 and the tubular member 4 arranged on the lower mold 82 together with the first and second columnar molds 83 and 84 and the rod-shaped mold 85. In FIG. 6, the cavity space 80 of the mold 8 into which the molten thermoplastic polymer material is injected is shown shaded in gray. FIG. 7(a) is a perspective view showing a part of the upper mold 81, and FIG. 7(b) is a perspective view showing a part of the lower mold 82.

[0046] The bushing insertion hole 301 of the insulator 30 is formed by the first columnar type 83, and the insulating plug insertion hole 302 of the insulator 30 is formed by the second columnar type 84. In the accommodation hole 312 of the first semiconductor 31, a part of each of the first and second columnar types 83, 84 is inserted, and the first semiconductor 31 is supported in the mold 8 by the first and second columnar types 83, 84 and the rod-shaped type 85. The second semiconductor 32 is supported in the mold 8 by the rod-shaped type 85.

[0047] In the upper mold 81 and the lower mold 82, first concave portions 811, 821 and second concave portions 812, 822 having shapes corresponding to the half-divided shapes of the holding cylinder portion 3A and the connection cylinder portion 3B of the cable holder 3 are respectively formed. The holding cylinder portion 3A is formed by the first concave portion 811 of the upper mold 81 and the first concave portion 821 of the lower mold 82, and the connection cylinder portion 3B is formed by the second concave portion 812 of the upper mold 81 and the second concave portion 822 of the lower mold 82.

[0048] For the third semiconductor 33, the cylindrical portion 331 is accommodated in the first concave portion 811 of the upper mold 81 and the first concave portion 821 of the lower mold 82, and the outer contour portion 334 is accommodated in the second concave portion 812 of the upper mold 81 and the second concave portion 822 of the lower mold 82. The outer peripheral surface 331a of the cylindrical portion 331 is in contact with the inner surface 811a of the first concave portion 811 of the upper mold 81 and the inner surface 821a of the first concave portion 821 of the lower mold 82, and the outer peripheral surface 334b of the outer contour portion 334 is in contact with the inner surface 812a of the second concave portion 812 of the upper mold 81 and the inner surface 822a of the second concave portion 822 of the lower mold 82. When the upper mold 81 and the lower mold 82 are mated, the first and second protruding piece portions 332, 333 of the third semiconductor 33 are sandwiched between the upper mold 81 and the lower mold 82.

[0049] As shown in Fig. 7(a), in the upper mold 81, a third concave portion 813 for accommodating a part of the first protruding piece portion 332 of the third semiconductor 33 and a fourth concave portion 814 for accommodating a part of the second protruding piece portion 333 of the third semiconductor 33 are provided in communication with the first concave portion 811. As shown in Fig. 7(b), in the lower mold 82, a third concave portion 823 for accommodating a part of the first protruding piece portion 332 of the third semiconductor 33 and a fourth concave portion 824 for accommodating a part of the second protruding piece portion 333 of the third semiconductor 33 are provided in communication with the first concave portion 821.

[0050] In the third recesses 813 and 823 of the upper mold 81 and the lower mold 82, respective parts in the thickness direction of the first protruding piece portion 332 are accommodated. In the fourth recesses 814 and 824 of the upper mold 81 and the lower mold 82, respective parts in the thickness direction of the second protruding piece portion 333 are accommodated. The first protruding piece portion 332 is sandwiched between the bottom surface 813a of the third recess 813 of the upper mold 81 and the bottom surface 823a of the third recess 823 of the lower mold 82, and the second protruding piece portion 333 is sandwiched between the bottom surface 814a of the fourth recess 814 of the upper mold 81 and the bottom surface 824a of the fourth recess 824 of the lower mold 82.

[0051] The lower mold 82 is provided with a first protrusion 825 inserted into the through hole 332a of the first protruding piece portion 332 and a second protrusion 826 inserted into the through hole 333a of the second protruding piece portion 333. The first protrusion 825 is erected on the bottom surface 823a of the third recess 823 of the lower mold 82, and the second protrusion 826 is erected on the bottom surface 824a of the fourth recess 824. The lengths of the first protrusion 825 and the second protrusion 826 are, for example, lengths corresponding to the thicknesses of the first protruding piece portion 332 and the second protruding piece portion 333.

[0052] Note that, instead of the first protrusion 825 and the second protrusion 826 of the lower mold 82, protrusions inserted into the through hole 332a of the first protruding piece portion 332 and protrusions inserted into the through hole 333a of the second protruding piece portion 333 may be provided on the upper mold 81. Further, protrusions inserted into the through hole 332a of the first protruding piece portion 332 may be provided on one of the upper mold 81 and the lower mold 82, and protrusions inserted into the through hole 333a of the second protruding piece portion 333 may be provided on the other of the upper mold 81 and the lower mold 82.

[0053] In the insulator forming process, with the first and second protruding pieces 332 and 333 sandwiched between the upper mold 81 and the lower mold 82, and the first and second protrusions 825 and 826 inserted into the through holes 332a and 333a of the first and second protruding pieces 332 and 333, a molten thermoplastic polymer material is injected into the cavity space 80 in the mold 8. As this thermoplastic polymer material solidifies to form the insulator 30, a cable holder 3 with the tubular member 4 fixed to its end is obtained. The thermoplastic polymer material also enters the plurality of through holes 410 formed in the embedding portion 41 of the tubular member 4 to prevent the tubular member 4 from coming off.

[0054] As shown in FIG. 6, the rod-shaped mold 85 has a tip portion 851 disposed in the terminal insertion hole 311 of the first semiconductor 31, a small-diameter shaft portion 852 disposed in a portion that becomes the small-diameter hole portion 21 of the insertion hole 20, a tapered shaft portion 853 disposed in a portion that becomes the tapered hole portion 22 of the insertion hole 20, a medium-diameter shaft portion 854 disposed in a portion that becomes the large-diameter hole portion 23 of the insertion hole 20, and a large-diameter shaft portion 855 disposed inside the cylindrical portion 42 of the tubular member 4 integrally.

[0055] FIG. 8(a) is an explanatory diagram showing the tubular member 4 and its peripheral portion in the arrangement process. In FIG. 8(a), the small-diameter shaft portion 852, the tapered shaft portion 853, the medium-diameter shaft portion 854, the large-diameter shaft portion 855, and the O-ring 86 in a portion above the central axis C of the rod-shaped mold 85 are shown in cross section. FIG. 8(b) is an explanatory diagram showing a state when the rod-shaped mold 85 is being removed from the cable holder 3 and the tubular member 4 after the insulator 30 is formed. FIG. 9 is an enlarged view showing a part of FIG. 8(a) enlarged.

[0056] An annular groove 855b is formed on the outer peripheral surface 855a of the end portion on the medium-diameter shaft portion 854 side in the axial direction of the large-diameter shaft portion 855. An O-ring 86 as an annular elastic body is accommodated in this annular groove 855b. The O-ring 86 elastically contacts the inner peripheral surface 42a of the cylindrical portion 42 of the tubular member 4 to prevent the thermoplastic polymer material from flowing to the side of the small-diameter portion 422 rather than the O-ring 86.

[0057] An annular stepped portion 423 is formed on the inner peripheral surface 42a of the cylindrical portion 42. As shown in FIG. 8(b), the inner diameter D1 of the portion on the embedding portion 41 side with respect to the stepped portion 423 is smaller than the inner diameter D2 of the portion on the side opposite to the embedding portion 41 with respect to the stepped portion 423, and is formed to be slightly larger than the outer diameter D3 of the large-diameter shaft portion 855. The annular groove 855b of the rod-shaped mold 85 is formed on the outer peripheral surface 855a of the large-diameter shaft portion 855 of the portion arranged on the embedding portion 41 side with respect to the stepped portion 423 in the arrangement process. Hereinafter, the inner peripheral surface 42a of the cylindrical portion 42 in the portion on the embedding portion 41 side with respect to the stepped portion 423 is referred to as a small-diameter inner peripheral surface 42b, and the inner peripheral surface 42a of the cylindrical portion 42 in the portion on the side opposite to the embedding portion 41 with respect to the stepped portion 423 is referred to as a large-diameter inner peripheral surface 42c.

[0058] The O-ring 86 is compressed in the radial direction of the large-diameter shaft portion 855 within the annular groove 855b and elastically contacts the small-diameter inner peripheral surface 42b in the arrangement process and the insulator molding process. The difference between the inner diameter D1 of the small-diameter inner peripheral surface 42b in the cylindrical portion 42 and the outer diameter D3 of the large-diameter shaft portion 855 is a dimension that can suppress the entry of the thermoplastic polymer material into the gap between the small-diameter inner peripheral surface 42b and the outer peripheral surface 855a of the large-diameter shaft portion 855. However, when the O-ring 86 elastically contacts the small-diameter inner peripheral surface 42b, it is possible to surely prevent the thermoplastic polymer material from flowing to the small-diameter portion 422 side with respect to the O-ring 86.

[0059] When pulling out the rod-shaped mold 85 from the cable holder 3 and the tubular member 4, the O-ring 86 slides on the small-diameter inner peripheral surface 42b. When the O-ring 86 crosses the stepped portion 423, the O-ring 86 faces the large-diameter inner peripheral surface 42c and the compression amount of the O-ring 86 is relaxed, and the frictional force generated between the O-ring 86 and the tubular member 4 becomes small. Thereby, the rod-shaped mold 85 can be easily pulled out and the wear of the O-ring 86 can be suppressed. Also, when inserting the rod-shaped mold 85 inside the tubular member 4 in the arrangement process, the insertion operation of the rod-shaped mold 85 becomes easy and the wear of the O-ring 86 can be suppressed.

[0060] (Operations and Effects of the Embodiment) According to the embodiments described above, an annular stepped portion 423 is formed on the inner peripheral surface 42a of the cylindrical portion 42 of the tubular member 4, and the inner diameter D2 of the large-diameter inner peripheral surface 42c is larger than the inner diameter D1 of the small-diameter inner peripheral surface 42b on the embedding portion 41 side of the stepped portion 423. Therefore, it becomes easier to insert and remove the rod-shaped die 85 with respect to the tubular member 4, and the workability during manufacturing is improved. Further, since the rod-shaped die 85 integrally has a small-diameter shaft portion 852, a tapered shaft portion 853, a medium-diameter shaft portion 854, and a large-diameter shaft portion 855, the small-diameter hole portion 21, the tapered hole portion 22, and the large-diameter hole portion 23 of the insertion hole 20 can be easily formed.

[0061] (Summary of the Embodiment) Next, the technical idea grasped from the embodiments described above will be described by referring to the reference numerals and the like in the embodiments. However, each reference numeral in the following description is not limited to the member or the like that specifically shows the component in the claims in the embodiments.

[0062] [1]A power cable end connection part (2) to which the end part of a power cable (1) having a central conductor (11), an insulating layer (12) covering the outer periphery of the central conductor (11), a shielding layer (13) composed of a plurality of shield wires (131) arranged so as to surround the outer periphery of the insulating layer (12), and a sheath (14) covering the outer periphery of the shielding layer (13) is connected. The power cable end connection part (2) includes a cable holder (3) having an insertion hole (20) into which the central conductor (11) and the insulating layer (12) of the power cable (1) are inserted, and a metal tubular member (4) fixed to an end of the cable holder (3) through which the central conductor (11) and the insulating layer (12) are inserted and which houses a part of the shielding layer (13) and the sheath (14). The cable holder (3) has an insulator (12) formed of a polymer-based material and a semiconductor (31 to 33) formed of a polymer-based material imparted with conductivity by a conductivity-imparting agent. The tubular member (4) has an embedded part (41) embedded in the cable holder (3) and a cylindrical part (42) exposed from the cable holder (3). The embedded part (41) and the cylindrical part (42) are arranged in the axial direction along the longitudinal direction of the power cable (1). An annular step part (423) is formed on the inner peripheral surface (42a) of the cylindrical part (42), and the inner diameter (D1) of the part on the embedded part (41) side with respect to the step part (423) is smaller than the inner diameter (D2) of the part on the side opposite to the embedded part (41) with respect to the step part (423). Power cable end connection part (2).

[0063] [2]A manufacturing method for manufacturing the power cable end connection part (2) according to [1] above. The manufacturing method has an insulator molding step of injection molding the insulator (30) of the cable holder (3) using a rod-shaped member (85) inserted inside the tubular member (4). An annular groove (855b) is formed on the outer peripheral surface (855a) of the part of the rod-shaped member (85) arranged on the embedded part (41) side with respect to the step part (423) in the insulator molding step, and an annular elastic body (86) is accommodated in the annular groove (855b). The elastic body (86) elastically contacts the inner peripheral surface (42b) of the cylindrical part (42) on the embedded part (41) side with respect to the step part (423). Manufacturing method of power cable end connection part (2).

[0064] [3] The rod-shaped member (85) integrally has a small-diameter shaft portion (852) disposed at a portion that becomes the insertion hole (20) and a large-diameter shaft portion (855) disposed inside the cylindrical portion (42). The manufacturing method of the power cable terminal connection portion (2) according to [2] above.

[0065] As described above, the embodiments of the present invention have been described. However, the embodiments described above do not limit the invention according to the claims. It should also be noted that not all combinations of the features described in the embodiments are essential means for solving the problems of the invention.

Explanation of reference numerals

[0066] 1... Power cable 11... Central conductor 12... Insulation layer 13... Shielding layer 14... Sheath 2... Power cable terminal connection portion 20... Insertion hole 3... Cable holder 30... Insulator 31 to 33... First to third semiconductors 4... Tubular member 41... Embedded portion 42... Cylindrical portion 42a... Inner peripheral surface 85... Rod-shaped (rod-shaped member) 852... Small-diameter shaft portion 855... Large-diameter shaft portion 86... O-ring (elastic body)

Claims

1. A power cable terminal connection part to which a terminal part of a power cable having a central conductor, an insulating layer covering the outer periphery of the central conductor, a shielding layer composed of a plurality of shield wires arranged so as to surround the outer periphery of the insulating layer, and a sheath covering the outer periphery of the shielding layer is connected, a cable holder having an insertion hole into which the central conductor and the insulating layer of the power cable are inserted, and a metal tubular member fixed to an end of the cable holder, through which the central conductor and the insulating layer are inserted and which houses a part of the shielding layer and the sheath. The cable holder has an insulator formed of a polymer-based material and a semiconductor formed of a polymer-based material to which conductivity is imparted by a conductivity-imparting agent. The tubular member has an embedded part embedded in the cable holder and a cylindrical part exposed from the cable holder, and the embedded part and the cylindrical part are arranged in an axial direction along the longitudinal direction of the power cable. An annular step portion is formed on the inner peripheral surface of the cylindrical part, and the inner diameter of the portion on the embedded part side with respect to the step portion is smaller than the inner diameter of the portion on the side opposite to the embedded part with respect to the step portion. Power cable terminal connection part.

2. A manufacturing method for manufacturing the power cable terminal connection part according to Claim 1, having an insulator molding step of injection molding the insulator of the cable holder using a rod-shaped member inserted inside the tubular member, wherein an annular groove is formed on an outer peripheral surface of a portion of the rod-shaped member arranged on the embedded part side with respect to the step portion in the insulator molding step, and an annular elastic body is housed in the annular groove, and the elastic body elastically contacts the inner peripheral surface of the cylindrical part on the embedded part side with respect to the step portion. Manufacturing method of power cable terminal connection part.

3. The rod-shaped member integrally has a small-diameter shaft portion arranged at a portion that becomes the insertion hole and a large-diameter shaft portion arranged inside the cylindrical part. The manufacturing method of the power cable terminal connection part according to Claim 2.

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