Power cable holder and method for manufacturing power cable holder

Abstract

To provide a power cable holder capable of suppressing deformation of a semiconductor during molding of an insulator formed of a polymer material inside a semiconductor having a cylindrical portion formed of the polymer material to which conductivity is imparted by a conductivity imparting agent, and a method for manufacturing the same.SOLUTION: A cable holder 3 integrally includes first to third semiconductors 31 to 33, and an insulator 30 interposed between the first to third semiconductors 31 to 33. The first semiconductor 31 includes a terminal accommodating portion 311 that accommodates a compression terminal 10 attached to a central conductor 11, and the insulator 30 covers the outer periphery of the terminal accommodating portion 311 and the outer periphery of the second semiconductor 32. The third semiconductor 33 integrally includes a cylindrical portion 331 covering at least a portion of the insulator 30 on the outer periphery of the terminal accommodating portion 311, and a plurality of projecting pieces 332 and 333 projecting radially outward from the outer peripheral surface 331a of the cylindrical portion 331.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power cable holder into which an end of a stepped stripped power cable is inserted, and a method for manufacturing the same. [Background technology]

[0002] The present applicant has previously proposed a polymer joint for power cables, which is applicable to devices such as transformers and gas-insulated switchgears, as disclosed in Patent Document 1. This polymer joint for power cables is primarily made of a polymer-based material and includes a polymer protective layer having a cable insertion hole into which the end of the power cable is inserted, an insulating plug that connects a compression terminal connected to the power cable conductor to the device-side conductor of the device, and a waterproofing treatment portion that seals the rear end of the polymer protective layer. The polymer protective layer includes an insulator made of a polymer-based material, first and second semiconductive portions that reduce the electric field of the power cable, a protective cover that protects the front end of the insulator, and a metal tubular member provided on the rear end of the insulator. The protective cover is cylindrically formed around the outer periphery of the insertion hole. The insulator, first and second semiconductive portions, protective cover, and tubular member are integrally molded. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-116277 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technique described in Patent Document 1, when the protective cover is formed from a polymer material that has been made conductive with a conductivity-imparting agent, a protective cover that has been injection-molded in advance is placed in a mold for molding, and a thermoplastic polymer material that will serve as an insulator is injected into the cavity of the mold. During this process, if the protective cover is deformed inside the mold due to the fluid pressure of the molten, liquid thermoplastic polymer material, the thermoplastic polymer material will get between the protective cover and the inner surface of the mold, and a polymer molded product with a protective cover of the desired shape will not be obtained.

[0005] Therefore, the present invention provides a power cable holder in which an insulator made of a polymer-based material is provided inside a semi-conductor having a cylindrical portion made of a polymer-based material that has been made conductive by a conductivity-imparting agent, and the power cable holder is capable of suppressing deformation of the semi-conductor during molding of the insulator, and a method for manufacturing the same. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a power cable holder having an insertion hole into which a power cable having a central conductor and an insulating layer covering the central conductor is inserted, the power cable holder comprising: first to third semi-conductors formed from a polymer-based material to which conductivity has been imparted by a conductivity imparting agent; and insulators made of a polymer-based material and integrally formed with the first to third semi-conductors, the insulators being interposed between the first semi-conductor and the second semi-conductor, between the first semi-conductor and the third semi-conductor, and between the second semi-conductor and the third semi-conductor, respectively; the first semi-conductor has a terminal accommodating portion for accommodating a compression terminal attached to the central conductor; and the second semi-conductor has a terminal accommodating portion for accommodating a compression terminal attached to the central conductor. a power cable holder arranged alongside a first semi-conductor in the longitudinal direction of the power cable, with a through hole formed in the center for inserting the insulating layer; the insulator covering the outer periphery of the terminal accommodating portion of the first semi-conductor and the outer periphery of the second semi-conductor, and covering the insulating layer between the first semi-conductor and the second semi-conductor; the third semi-conductor integrally having a cylindrical portion covering at least a portion of the insulator on the outer periphery of the terminal accommodating portion of the first semi-conductor, and a plurality of protruding pieces protruding radially outward from the outer periphery of the cylindrical portion; and at least a portion of the insulator on the outer periphery of the second semi-conductor is not covered by the cylindrical portion of the third semi-conductor.

[0007] Furthermore, in order to solve the above-mentioned problems, the present invention provides a manufacturing method for the above-mentioned power cable retainer, comprising a semiconductor molding step of molding the first to third semi-conductors, an arrangement step of arranging the first to third semi-conductors and the tubular member in a mold, and an insulator molding step of injecting a thermoplastic polymer material into the mold to form the insulator, wherein the mold has an upper mold and a lower mold that sandwich the multiple protrusions, and in the insulator molding step, the thermoplastic polymer material is injected into the mold with the multiple protrusions sandwiched between the upper mold and the lower mold. [Effects of the Invention]

[0008] According to the present invention, in a power cable holder in which an insulator made of a polymer-based material is provided inside a semi-conductor having a cylindrical portion made of a polymer-based material that has been made conductive by a conductivity imparting agent, it is possible to suppress deformation of the semi-conductor during molding of the insulator. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view specifically showing an example of a power cable connection structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the power cable taken along line AA in FIG. [Figure 3] 10(a) and 10(b) are side views of the third semiconductor viewed from different directions. [Figure 4] 1(a) is a perspective view showing a tubular member of a power cable, and FIG. 1(b) is a perspective cross-sectional view of the tubular member at line BB in FIG. [Figure 5] FIG. 10 is an explanatory diagram showing a mold for molding an insulator together with a third semi-conductor. [Figure 6] FIG. 2 is an explanatory view showing the first to third semi-conductors and tubular member arranged in the lower mold together with the first and second columnar molds and the rod-shaped mold. [Figure 7] 1(a) is a perspective view showing a part of an upper mold, and FIG. 1(b) is a perspective view showing a part of a lower mold. [Figure 8] 10(a) and 10(b) are explanatory views showing a manufacturing process of a terminal connection part of a power cable. [Figure 9] FIG. 8(b) is an enlarged view showing a part of FIG. 8(a). DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment Mode] A power cable holder and a manufacturing method thereof according to an 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 a power cable holder according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of a power cable taken along line AA in Fig. 1. This power cable connection structure is a connection structure for connecting a power cable 1 that transmits 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) 2, the power cable 1 has a central conductor 11 formed by twisting together a plurality of wires 111, an insulating layer 12 covering the outer periphery of the central conductor 11, a shielding layer 13 made up of a plurality of shield wires 131 arranged to surround the outer periphery of the insulating layer 12, and a sheath 14 covering the outer periphery of the shielding layer 13. In this embodiment, an inner semiconductive layer 15 is provided between the central conductor 11 and the insulating layer 12, and an outer semiconductive layer 16 is provided between the insulating layer 12 and the shielding layer 13. A pressure wrapping tape 17 is spirally wound around the outer periphery of the shielding layer 13, and the outside of this is covered by the sheath 14.

[0012] The wires 111 of the central conductor 11 can be made of a wire material made of a highly conductive metal, such as a tin-plated annealed copper wire. The central conductor 11 transmits a high voltage of, for example, 7000 V or more. The insulating layer 12 is formed by extrusion molding a material such as ethylene propylene rubber, vinyl chloride, cross-linked polyethylene, silicone rubber, or a fluorine-based material. The sheath 14 is formed by extrusion molding a rubber, such as natural rubber, butyl rubber, halogenated butyl rubber, or non-halogenated polyolefin elastomer, to which a cross-linking agent or the like has been added. The shield wire 131 is made of a wire material, such as a tin-plated annealed copper wire, and is wound helically.

[0013] The inner and outer semiconductive layers 15, 16 are provided to reduce the concentration of electric fields and are mainly made of polymeric materials, which are formed by extrusion molding of conductive materials with conductive powder dispersed therein. The pressure wrapping tape 17 can be a strip made of, for example, plastic or rayon.

[0014] The power cable 1 has a terminal end connected to the power cable connection end 2 stripped in stages, exposing each layer in stages. Specifically, the sheath 14 and the pressure wrapping tape 17 are partially removed to expose the multiple shield wires 131, the outer semiconductive layer 16 is partially removed to expose the insulating layer 12, and the insulating layer 12 and the inner semiconductive layer 15 are partially removed to expose the center conductor 11.

[0015] A compression terminal 10 is attached to the central conductor 11 exposed from the insulating layer 12. The compression terminal 10 has a cylindrical crimped portion 101 that is crimped to compress the central conductor 11, and a flat connecting portion 102 that is formed integrally with the crimped portion 101. An accommodating hole 101a that accommodates the central conductor 11 is formed in the crimped portion 101. An equipment connecting hole 102a is formed at the tip of the connecting portion 102.

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

[0017] The power cable terminal connection part 2 includes a cable holder 3 provided with an insertion hole 20 into which the central conductor 11 and 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 waterproofing treatment part 5 that prevents water from entering the inside of the tubular member 4, an insulating plug 61 that connects the compression terminal 10 to the equipment side conductor 91 of the equipment 9, and a protective cap 62 that protects the insulating plug 61.

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

[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 voltage detector 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 a male thread 91a provided on the appliance-side conductor 91 screws. The voltage detector electrode 613 is formed with a tool fitting hole 613a into which the tip of a tool such as a socket wrench fits. The insulator 611 is molded integrally with the high-voltage electrode 612 and the voltage detector electrode 613.

[0020] The protective cap 62 is made of a semiconductive rubber material and is formed in a cylindrical shape with a bottom, integrally having a disk-shaped bottom wall 621 and a cylindrical side wall 622. The bottom wall 621 covers the insulating plug 61. The side wall 622 has an annular protrusion 622a formed on its inner circumferential surface for fixing to the cable holder 3.

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

[0022] The cable holder 3 has an insulator 30 made of a polymer material, and first to third semi-conductors 31 to 33 made of a polymer material that has been made conductive by dispersing a conductivity-imparting agent. The insulator 30 is provided across the holding tubular portion 3A and the connecting tubular portion 3B, and is provided around the insertion hole 20 in the holding tubular portion 3A. The insulator 30 in the connecting tubular portion 3B is also formed with 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.

[0023] The insulators 30 are respectively interposed between the first semi-conductor 31 and the second semi-conductor 32, between the first semi-conductor 31 and the third semi-conductor 33, and between the second semi-conductor 32 and the third semi-conductor 33, and are formed integrally with the first to third semi-conductors 31 to 33. The first to third semi-conductors 31 to 33 mitigate the electric field around the power cable 1. The third semi-conductor 33 also has a shielding function that prevents the electric field around the power cable 1 from leaking to the outside.

[0024] For example, silicone rubber, ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), etc. can be used as the polymer material of the insulator 30 and the first to third semi-conductors 31 to 33 in the cable holder 3. For example, conductive fine powder such as carbon black can be used as the conductivity imparting agent.

[0025] The first to third semi-conductors 31 to 33 are molded bodies that are injection-molded before forming the insulator 30. The first semi-conductor 31 surrounds the compression terminal 10 from the tip end of the holding cylindrical portion 3A to the connecting cylindrical portion 3B. The first semi-conductor 31 integrally includes a terminal accommodating portion 311 having a terminal insertion hole 311a into which the compression terminal 10 is inserted together with a longitudinal portion of the center conductor 11 and the insulating layer 12, and an insulating plug accommodating portion 312 having an insulating plug accommodating hole 312a that accommodates a portion of each of the device-side bushing 90 and the insulating plug 61.

[0026] The second semi-conductor 32 is aligned with the first semi-conductor 31 in the longitudinal direction of the power cable 1, and is disposed closer to the rear end of the holding tubular portion 3A than the first semi-conductor 31. An insertion hole 320 is formed in the center of the second semi-conductor 32, through which the insulating layer 12 is inserted. This insertion hole 320 is part of the insertion hole 20. The insulator 30 covers the outer periphery of the terminal accommodating portion 311 of the first semi-conductor 31 and the outer periphery of the second semi-conductor 32, and also covers the insulating layer 12 between the first semi-conductor 31 and the second semi-conductor 32.

[0027] 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 portion 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 portion of the small diameter hole portion 21 on the front end side is formed by a first semi-conductor 31, and a portion on the rear end side is formed by a second semi-conductor 32. Between the first semi-conductor 31 and the second semi-conductor 32, the small diameter hole portion 21 is formed by an insulator 30. A manufacturing method of the cable holder 3 will be described later.

[0028] Fig. 3(a) is a side view of the third semi-conductor 33 as seen from a direction perpendicular to the axial direction of the holding cylindrical portion 3A and the axial direction of the connecting cylindrical portion 3B, and Fig. 3(b) is a side view of the third semi-conductor 33 as seen from the rear end side along the axial direction of the holding cylindrical portion 3A. In Figs. 3(a) and 3(b), a ground wire 71 is shown together with the third semi-conductor 33.

[0029] The third semi-conductor 33 integrally includes a cylindrical portion 331 that covers the insulator 30 around the insertion hole 20 in a portion of the tip side of the holding cylindrical portion 3A, including the outer periphery of the first semi-conductor 31, first and second protrusions 332, 333 that protrude radially outward from an outer periphery 331a of the cylindrical portion 331, and an outer shell portion 334 that forms the outer shell of the connecting cylindrical portion 3B. The cylindrical portion 331 covers at least a portion of the insulator 30 on the outer periphery of the terminal accommodating portion 311 of the first semi-conductor 31. The outer shell portion 334 is formed in a cylindrical shape so as to cover the insulator 30 in the connecting cylindrical portion 3B. The outer shell portion 334 has an annular recess 334a formed on an outer periphery 334b ​​that engages with a protrusion 622a formed on a side wall 622 of the protective cap 62.

[0030] At least a portion of the insulator 30 on the outer periphery of the second semi-conductor 32 is not covered by the cylindrical portion 331 of the third semi-conductor. That is, the insulator 30 is exposed to the outside on the outer periphery of the second semi-conductor 32. Furthermore, the first and second semi-conductors 31, 32 and the tubular member 4 are not in contact with each other and are electrically insulated by the insulator 30.

[0031] The first protruding piece 332 and the second protruding piece 333 are provided at symmetrical positions sandwiching the insertion hole 20. In other words, the first and second protruding pieces 332, 333 are provided at positions spaced 180° apart in the circumferential direction of the cylindrical portion 331. The first protruding piece 332 has a through-hole 332a formed therethrough. The second protruding piece 333 has a through-hole 333a formed therethrough.

[0032] In this embodiment, when the third semi-conductor 33 is viewed from a direction perpendicular to the axial direction of the holding cylindrical portion 3A and the axial direction of the connecting cylindrical portion 3B, the first and second protrusions 332, 333 are formed in a triangular shape. However, the shapes of the first and second protrusions 332, 333 are not limited to this and may be, for example, a square or semicircular shape.

[0033] An earth wire 71 is connected to the first protrusion 332. The earth wire 71 has an earth wire 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 body 711. The earth terminal 712 is attached to the first protrusion 332 by a bolt 72 and a nut 73. A threaded portion 721 of the bolt 72 is inserted into the through hole 332a of the first protrusion 332.

[0034] The earth wire 71 may be connected to the second protrusion 333. In this case, the threaded portion 721 of the bolt 72 is inserted into the through hole 333a of the second protrusion 333. When the earth wire 71 is connected to the first protrusion 332, the second protrusion 333 does not need to have the through hole 333a, and when the earth wire 71 is connected to the second protrusion 333, the first protrusion 332 does not need to have the through hole 332a. In other words, it is sufficient that at least one of the first and second protrusions 332, 333 has a through hole that penetrates the protrusion.

[0035] The tubular member 4 is fixed to the rear end of the cable holder 3, and allows the central conductor 11 and insulating layer 12 of the power cable 1 to pass through it, while also accommodating the shielding layer 13 and part of the sheath 14. The tubular member 4 is made of a highly conductive metal such as brass or an aluminum alloy. The multiple shield wires 131 of the shielding layer 13 are led out of the sheath 14 inside the tubular member 4, folded back around the outer periphery of the sheath 14, and led out of the tubular member 4 from between the outer periphery 14a of the sheath 14 and the inner periphery 4a of the tubular member 4.

[0036] 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 BB in Fig. 4(a). The tubular member 4 integrally comprises 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.

[0037] Embedded portion 41 is cylindrical, and has through holes 410 formed at multiple locations (four locations in this embodiment) in the circumferential direction, penetrating embedded portion 41 in the axial direction. Insulator 30 fits into the multiple through holes 410. Embedded portion 41 is embedded in insulator 30 in a portion of tapered hole portion 22 of insertion hole 20 and in a portion that corresponds to the outer circumferential side of large diameter hole portion 23.

[0038] The embedded portion 41 and the cylindrical portion 42 are aligned 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 which have 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 of the large diameter portion 421 on the opposite side to the embedded portion 41. The waterproof tape 51 of the waterproofing treatment portion 5 is wrapped around the outer peripheral surface 422a of the small diameter portion 422.

[0039] The embedded portion 41 is formed to have a smaller outer diameter than the large diameter portion 421 and the small diameter portion 422. The embedded portion 41 is also formed to have a thinner radial thickness than the large diameter portion 421 and the small diameter portion 422. An 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 embedded portion 41 side.

[0040] Furthermore, in the tubular member 4, an earth wire connection portion 401 to which the earth wire 74 is connected, and shield wire connection portions 402 to which multiple shield wires 131 are connected are provided on the cylindrical portion 42. The earth wire connection portion 401 is provided in a portion that is not covered by the waterproofing treatment portion 5, and the shield wire connection portion 402 is provided in a portion that is covered by the waterproofing treatment portion 5. In this embodiment, the earth 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 multiple locations in the circumferential direction of the small diameter portion 422. The earth wire connection portion 401 is part of the large diameter portion 421, and the shield wire connection portions 402 are part of the small diameter portion 422.

[0041] Connection terminals 75 are attached to the tips of the multiple shield wires 131. In the present embodiment, the shielding layer 13 includes 20 shield wires 131, and ten of these shield wires 131 are electrically connected to the tubular member 4 by two connection terminals 75. 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 waterproofing treatment portion 5 covers the 20 shield wires 131 extending from the tubular member 4 together with the two connection terminals 75.

[0042] The two connection terminals 75 are each connected to the shield wire connection portion 402 by a bolt 76. The shield wire connection portion 402 is formed with a threaded hole 402a into which the bolt 76 for connecting the connection terminal 75 is threaded. In this embodiment, the threaded hole 402a passes radially through the small diameter portion 422. However, the threaded hole 402a does not have to pass through the small diameter portion 422. The periphery of the opening of the threaded hole 402a in the outer peripheral surface 422a of the small diameter portion 422 is formed as a flat surface 402b perpendicular to the central axis of the threaded hole 402a to ensure reliable connection of the connection terminals 75 by tightening the bolt 76.

[0043] The earth wire 74 has an earth wire body 741 made of an insulated wire whose core is covered with an insulator, and an earth terminal 742 attached to the tip of the earth wire body 741. The earth wire connection portion 401 has a threaded hole 401a into which a bolt 77 for connecting the earth terminal 742 screws, the threaded hole 401a opening in the outer circumferential surface 421a of the large diameter portion 421 of the tubular member 4 so as not to penetrate the tubular member 4. The periphery of the opening of the threaded hole 401a in the outer circumferential surface 421a of the large diameter portion 421 forms a flat surface 401b perpendicular to the central axis of the threaded hole 401a to ensure reliable connection of the earth terminal 742 by tightening the bolt 77.

[0044] As shown in FIG. 4(b), the thickness T1 of the embedded portion 41 in the radial direction of the tubular member 4 is thinner than the thickness T2 of the ground wire connection portion 401 in the radial direction of the tubular member 4. Here, the thickness T2 of the ground wire connection portion 401 is the distance between the flat surface 401b of the screw hole 401a and the inner circumferential surface 4a of the tubular member 4 in the central axial direction. The thickness T1 of the embedded portion 41 is thinner than the thickness T3 of the shield wire connection portion 402 in the radial direction of the tubular member 4. Here, the thickness T3 of the shield wire connection portion 402 is the distance between the flat surface 402b of the screw hole 402a and the inner circumferential surface 4a of the tubular member 4 in the central axial direction. The thickness T1 of the embedded portion 41 is, for example, half or less the thickness T2 of the ground wire connection portion 401. The thickness T1 of the embedded portion 41 is, for example, 4 to 5 mm, and the thickness T2 of the ground wire connection portion 401 is, for example, 15 mm.

[0045] (Method of manufacturing the power cable terminal 2 and the cable holder 3) Next, a manufacturing method for the power cable connection terminal 2 and the cable holder 3 will be described with reference to Figures 5 to 9. This manufacturing method includes a semi-conductor molding step of molding the first to third semi-conductors 31 to 33, an arrangement step of arranging the first to third semi-conductors 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 semi-conductor molding step, each of the first to third semi-conductors 31 to 33 is injection-molded by injecting a thermoplastic polymer material, in which conductive powder has been dispersed to make it conductive, into a mold.

[0046] 5 is an explanatory diagram showing a mold 8 for molding the insulator 30 together with the third semi-conductor 33. The mold 8 has an upper mold 81 and a lower mold 82, first and second columnar molds 83 and 84, and a rod-shaped mold 85 for forming the insertion hole 20. The first and second columnar molds 83 and 84 and the rod-shaped mold 85 are movable back and forth in a direction perpendicular to the direction of relative movement between the upper mold 81 and the lower mold 82.

[0047] As an example, the lower mold 82 is fixed to a mold table, and the upper mold 81 moves up and down in the vertical direction relative to the lower mold 82. The first and second columnar molds 83, 84 and the rod-shaped mold 85 move forward and backward in the horizontal direction relative 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 move away 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, 84.

[0048] Fig. 6 is an explanatory diagram showing the first to third semi-conductors 31 to 33 and the tubular member 4 arranged in the lower mold 82, together with the first and second columnar molds 83, 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 by gray shading. 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.

[0049] The bushing insertion hole 301 of the insulator 30 is formed by the first columnar die 83, and the insulating plug insertion hole 302 of the insulator 30 is formed by the second columnar die 84. A portion of each of the first and second columnar dies 83, 84 is inserted into the insulating plug receiving hole 312a of the first semi-conductor 31, and the first semi-conductor 31 is supported in the die 8 by the first and second columnar dies 83, 84 and the rod-shaped die 85. The second semi-conductor 32 is supported in the die 8 by the rod-shaped die 85.

[0050] The upper mold 81 and the lower mold 82 are respectively formed with first recesses 811, 821 and second recesses 812, 822 having shapes corresponding to the half shapes of the holding tube portion 3A and the connecting tube portion 3B of the cable holder 3. The holding tube portion 3A is formed by the first recess 811 of the upper mold 81 and the first recess 821 of the lower mold 82, and the connecting tube portion 3B is formed by the second recess 812 of the upper mold 81 and the second recess 822 of the lower mold 82.

[0051] The third semi-conductor 33 has a cylindrical portion 331 accommodated in a first recess 811 of the upper mold 81 and a first recess 821 of the lower mold 82, and an outer portion 334 accommodated in a second recess 812 of the upper mold 81 and a second recess 822 of the lower mold 82. An outer peripheral surface 331a of the cylindrical portion 331 contacts an inner surface 811a of the first recess 811 of the upper mold 81 and an inner surface 821a of the first recess 821 of the lower mold 82, and an outer peripheral surface 334b ​​of the outer portion 334 contacts an inner surface 812a of the second recess 812 of the upper mold 81 and an inner surface 822a of the second recess 822 of the lower mold 82. When the upper mold 81 and the lower mold 82 are mated, the first and second protruding pieces 332, 333 of the third semi-conductor 33 are sandwiched between the upper mold 81 and the lower mold 82.

[0052] 7(a), the upper mold 81 is provided with a third recess 813 that accommodates a portion of the first protrusion 332 of the third semi-conductor 33, and a fourth recess 814 that accommodates a portion of the second protrusion 333 of the third semi-conductor 33, which are in communication with the first recess 811. As shown in FIG. 7(b), the lower mold 82 is provided with a third recess 823 that accommodates a portion of the first protrusion 332 of the third semi-conductor 33, and a fourth recess 824 that accommodates a portion of the second protrusion 333 of the third semi-conductor 33, which are in communication with the first recess 821.

[0053] A portion of the first protrusion 332 in the thickness direction is accommodated in the third recesses 813, 823 of the upper mold 81 and the lower mold 82. A portion of the second protrusion 333 in the thickness direction is accommodated in the fourth recesses 814, 824 of the upper mold 81 and the lower mold 82. The first protrusion 332 is sandwiched between a bottom surface 813a of the third recess 813 of the upper mold 81 and a bottom surface 823a of the third recess 823 of the lower mold 82, and the second protrusion 333 is sandwiched between a bottom surface 814a of the fourth recess 814 of the upper mold 81 and a bottom surface 824a of the fourth recess 824 of the lower mold 82.

[0054] The lower mold 82 is provided with a first protrusion 825 that is inserted into the through hole 332a of the first protrusion 332, and a second protrusion 826 that is inserted into the through hole 333a of the second protrusion 333. The first protrusion 825 stands upright on the bottom surface 823a of the third recess 823 of the lower mold 82, and the second protrusion 826 stands upright 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 that correspond to the thicknesses of the first protrusion 332 and the second protrusion 333.

[0055] Note that instead of the first protrusion 825 and the second protrusion 826 of the lower mold 82, a protrusion to be inserted into the through hole 332a of the first protrusion 332 and a protrusion to be inserted into the through hole 333a of the second protrusion 333 may be provided on the upper mold 81. Furthermore, a protrusion to be inserted into the through hole 332a of the first protrusion 332 may be provided on one of the upper mold 81 and the lower mold 82, and a protrusion to be inserted into the through hole 333a of the second protrusion 333 may be provided on the other of the upper mold 81 and the lower mold 82.

[0056] In the insulator molding process, the first and second protrusions 332, 333 are sandwiched between the upper mold 81 and the lower mold 82, and the first and second protrusions 825, 826 are inserted into the through holes 332a, 333a of the first and second protrusions 332, 333. In this state, molten thermoplastic polymer material is injected into the cavity space 80 in the mold 8. This thermoplastic polymer material solidifies to become the insulator 30, thereby obtaining the cable holder 3 with the tubular member 4 fixed to its end. The thermoplastic polymer material also fills the multiple through holes 410 formed in the embedding portion 41 of the tubular member 4, preventing the tubular member 4 from slipping out.

[0057] As shown in FIG. 6 , the rod-shaped mold 85 integrally has a tip portion 851 that is placed inside the terminal insertion hole 311a of the first semi-conductor 31, a small diameter shaft portion 852 that is placed in the portion that will become the small diameter hole portion 21 of the insertion hole 20, a tapered shaft portion 853 that is placed in the portion that will become the tapered hole portion 22 of the insertion hole 20, a medium diameter shaft portion 854 that is placed in the portion that will become the large diameter hole portion 23 of the insertion hole 20, and a large diameter shaft portion 855 that is placed inside the cylindrical portion 42 of the tubular member 4.

[0058] Fig. 8(a) is an explanatory diagram showing the tubular member 4 and its surrounding area in the arrangement step. Fig. 8(a) shows a cross section of the small-diameter shaft portion 852, tapered shaft portion 853, medium-diameter shaft portion 854, large-diameter shaft portion 855, and O-ring 86 in the portion above the central axis C of the rod-shaped mold 85. Fig. 8(b) is an explanatory diagram showing the state when the rod-shaped mold 85 is being removed from the cable holder 3 and the tubular member 4 after the insulator 30 has been formed. Fig. 9 is an enlarged view showing a portion of Fig. 8(a).

[0059] An annular groove 855b is formed in the outer peripheral surface 855a of the large diameter shaft portion 855 at the end portion on the medium diameter shaft portion 854 side in the axial direction. An O-ring 86 serving as an annular elastic body is housed 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, and prevents the thermoplastic polymer material from flowing beyond the O-ring 86 toward the small diameter portion 422.

[0060] An annular step 423 is formed on the inner circumferential surface 42a of the cylindrical portion 42. As shown in FIG. 8(b), the inner diameter D1 of the portion closer to the embedded portion 41 than the step 423 is smaller than the inner diameter D2 of the portion opposite the embedded portion 41 than the step 423 and is 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 circumferential surface 855a of the large-diameter shaft portion 855 at a portion that is disposed closer to the embedded portion 41 than the step 423 in the disposing step. Hereinafter, the inner circumferential surface 42a of the cylindrical portion 42 at the portion closer to the embedded portion 41 than the step 423 will be referred to as the small-diameter inner circumferential surface 42b, and the inner circumferential surface 42a of the cylindrical portion 42 at the portion opposite the embedded portion 41 than the step 423 will be referred to as the large-diameter inner circumferential surface 42c.

[0061] In the placement step and the insulator molding step, the O-ring 86 is compressed in the annular groove 855b in the radial direction of the large-diameter shaft portion 855 and comes into elastic contact with the small-diameter inner circumferential surface 42b. The difference between the inner diameter D1 of the small-diameter inner circumferential surface 42b of the cylindrical portion 42 and the outer diameter D3 of the large-diameter shaft portion 855 is a dimension that is sufficient to prevent the thermoplastic polymer material from entering the gap between the small-diameter inner circumferential surface 42b and the outer circumferential surface 855a of the large-diameter shaft portion 855. However, the elastic contact of the O-ring 86 with the small-diameter inner circumferential surface 42b reliably prevents the thermoplastic polymer material from flowing toward the small-diameter portion 422 from the O-ring 86.

[0062] When the rod-shaped die 85 is pulled out from the cable holder 3 and the tubular member 4, the O-ring 86 slides on the small-diameter inner circumferential surface 42b. When the O-ring 86 passes the step 423, the O-ring 86 faces the large-diameter inner circumferential surface 42c, reducing the amount of compression of the O-ring 86 and reducing the frictional force generated between the O-ring 86 and the tubular member 4. This makes it possible to easily pull out the rod-shaped die 85 and suppress wear on the O-ring 86. Furthermore, when inserting the rod-shaped die 85 into the tubular member 4 in the arrangement step, the insertion operation of the rod-shaped die 85 is also facilitated and wear on the O-ring 86 can be suppressed.

[0063] (Actions and Effects of the Embodiments) According to the embodiment described above, the insulator 30 is molded with the first and second protruding pieces 332, 333 of the third semi-conductor 33 sandwiched between the upper mold 81 and the lower mold 82, thereby preventing the third semi-conductor 33 from being deformed by the fluid pressure of the thermoplastic polymer material during molding. Furthermore, the first and second protruding pieces 332, 333 have through holes 332a, 333a formed therein, and the first and second protrusions 825, 826 of the lower mold 82 are inserted into the through holes 332a, 333a, thereby more reliably preventing deformation of the third semi-conductor 33. This prevents the thermoplastic polymer material from entering between the third semi-conductor 33 and the inner surface of the mold 8 (the inner surface 811a of the first recess 811 of the upper mold 81 and the inner surface 821a of the first recess 821 of the lower mold 82), thereby enabling the power cable holder 3 to be obtained, which includes the third semi-conductor 33 in the desired shape.

[0064] Furthermore, according to the above embodiment, the first semi-conductor 31 and the tubular member 4 are electrically separated by the insulator 30, so it is possible to support a one-sided grounding structure in which the shield wire 131 of the power cable 1 is electrically grounded only at the end opposite the power cable termination 2, and the tubular member 4 is not electrically grounded. In other words, if the first semi-conductor 31 and the tubular member 4 were electrically connected, electrically grounding the first semi-conductor 31 would bring the tubular member 4 to ground potential, and further, the shield wire 131 in contact with the tubular member 4 would also be at ground potential, making it impossible to adopt the above-mentioned one-sided grounding structure. In contrast, according to the above embodiment, the insulating structure of the cable holder 3, in which the insulator 30 is interposed between the first to third semi-conductors 31 to 33 and between the first to third semi-conductors 31 to 33 and the tubular member 4, makes it possible to support the above-mentioned one-sided grounding structure, thereby increasing the user's design freedom.

[0065] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0066] [1] A power cable holder (3) having an insertion hole (20) into which a power cable (1) having a central conductor (11) and an insulating layer (12) covering the central conductor (11) is inserted, the power cable holder (3) comprising first to third semi-conductors (31 to 33) formed from a polymer material to which conductivity is imparted by a conductivity imparting agent, and a conductive layer (34) between the first semi-conductor (31) and the second semi-conductor (32), and a conductive layer (34) between the first semi-conductor (31) and the third semi-conductor (33). and an insulator (30) made of a polymer material that is interposed between the first semi-conductor (31) and the second semi-conductor (32) and between the third semi-conductor (33), respectively, and that is integrally formed with the first to third semi-conductors (31 to 33), the first semi-conductor (31) has a terminal accommodating portion (311) that accommodates a compression terminal (10) attached to the central conductor (11), and the second semi-conductor (32) is an insulator that is interposed between the first semi-conductor (31) and the power cable The insulators (30) are arranged in a line in the longitudinal direction of the cable (1), and an insertion hole (20) for inserting the insulating layer (30) is formed in the center thereof. The insulator (30) covers the outer periphery of the terminal accommodating portion (311) of the first semi-conductor (31) and the outer periphery of the second semi-conductor (32), and also covers the insulating layer (12) between the first semi-conductor (31) and the second semi-conductor (32). The third semi-conductor (33) is arranged in a line in the longitudinal direction of the cable (1), and an insertion hole (20) for inserting the insulating layer (30) is formed in the center thereof. The insulator (30) covers the outer periphery of the terminal accommodating portion (311) of the first semi-conductor (31) and the outer periphery of the second semi-conductor (32), and also covers the insulating layer (12) between the first semi-conductor (31) and the second semi-conductor (32). a cylindrical portion (331) that covers at least a portion of the insulator (30) on the outer periphery of the terminal accommodating portion (311) of the second semi-conductor (31), and a plurality of protruding pieces (332, 333) that protrude radially outward from an outer periphery (331a) of the cylindrical portion (331), and at least a portion of the insulator (30) on the outer periphery of the second semi-conductor (32) is not covered by the cylindrical portion (331) of the third semi-conductor (33).

[0067] [2] The power cable holder (3) according to the above [1], wherein at least one of the plurality of protrusions (332, 333) has a through hole (332, 333a) formed therein.

[0068] [3] A method for manufacturing the power cable holder (3) described in [1] or [2] above, comprising: a semiconductor molding step of molding the first to third semi-conductors (31 to 33); an arrangement step of arranging the first to third semi-conductors (31 to 33) in a mold (8); and an insulator molding step of injecting a thermoplastic polymer material into the mold (8) to mold the insulator (30), wherein the mold (8) has an upper mold (81) and a lower mold (82) that sandwich the multiple protrusions (332, 333), and in the insulator molding step, the thermoplastic polymer material is injected into the mold (8) in a state where the multiple protrusions (332, 333) are sandwiched between the upper mold (81) and the lower mold (82).

[0069] [4] A method for manufacturing the power cable holder (3) described in [2] above, comprising a semiconductor molding step of molding the first to third semi-conductors (31 to 33), a placement step of placing the first to third semi-conductors (31 to 33) in a mold (8), and an insulator molding step of injecting a thermoplastic polymer material into the mold (8) to mold the insulator (30), wherein the mold (8) has an upper mold (81) and a lower mold (82) that sandwich the plurality of protruding pieces (332, 333), a mold (81) and / or a lower mold (82) are provided with protrusions (825, 826) to be inserted into the through holes (332a, 333a), and in the insulator molding process, the thermoplastic polymer material is injected into the mold (8) in a state where the plurality of protruding pieces (332, 333) are sandwiched between the upper mold (81) and the lower mold (82) and the protrusions (825, 826) are inserted into the through holes (332a, 333a).

[0070] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the embodiments described above. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0071] 1...Power cable 2...Power cable terminal connection part 20...Insertion hole 3...Cable holder (power cable holder) 31 to 33... First to third semi-conductors 311... Terminal accommodating portion 320...Through-hole 331...Cylindrical portion 331a... outer peripheral surface 332... first protruding piece portion 332a...through hole 333...second protruding piece 333a...Through hole 8...Mold 81...Upper mold 82...Lower mold 825...First protrusion 826...Second protrusion

Claims

1. a power cable holder having an insertion hole into which a power cable having a central conductor and an insulating layer covering the central conductor is inserted, first to third semi-conductors formed from polymeric materials to which conductivity has been imparted by a conductivity imparting agent; insulators made of a polymer material that are interposed between the first semi-conductor and the second semi-conductor, between the first semi-conductor and the third semi-conductor, and between the second semi-conductor and the third semi-conductor, and that are formed integrally with the first to third semi-conductors; the first semi-conductor has a terminal accommodating portion that accommodates a compression terminal attached to the central conductor; the second semi-conductor is arranged alongside the first semi-conductor in the longitudinal direction of the power cable, and has an insertion hole formed in the center thereof for inserting the insulating layer therethrough; the insulator covers an outer periphery of the terminal accommodating portion of the first semi-conductor and an outer periphery of the second semi-conductor, and also covers the insulating layer between the first semi-conductor and the second semi-conductor; the third semi-conductor integrally includes a cylindrical portion that covers at least a portion of the insulator on the outer periphery of the terminal accommodating portion of the first semi-conductor, and a plurality of protruding pieces that protrude radially outward from the outer periphery of the cylindrical portion; A method for manufacturing a power cable holder, wherein at least a portion of the insulator on an outer periphery of the second semi-conductor is not covered by the cylindrical portion of the third semi-conductor, a semiconductor molding step of molding the first to third semiconductors, a placement step of placing the first to third semiconductors in a mold, and an insulator molding step of injecting a thermoplastic polymer material into the mold to mold the insulator, the mold has an upper mold and a lower mold that sandwich the plurality of protruding pieces, In the insulator molding step, the thermoplastic polymer material is injected into the mold in a state where the plurality of protruding pieces are sandwiched between the upper mold and the lower mold. A method for manufacturing a power cable holder.

2. A power cable holder having an insertion hole into which a power cable having a central conductor and an insulating layer covering the central conductor is inserted, first to third semi-conductors formed from polymeric materials to which conductivity has been imparted by a conductivity imparting agent; insulators made of a polymer material that are interposed between the first semi-conductor and the second semi-conductor, between the first semi-conductor and the third semi-conductor, and between the second semi-conductor and the third semi-conductor, and that are formed integrally with the first to third semi-conductors; the first semi-conductor has a terminal accommodating portion that accommodates a compression terminal attached to the central conductor; the second semi-conductor is arranged alongside the first semi-conductor in the longitudinal direction of the power cable, and has an insertion hole formed in the center thereof for inserting the insulating layer therethrough; the insulator covers an outer periphery of the terminal accommodating portion of the first semi-conductor and an outer periphery of the second semi-conductor, and also covers the insulating layer between the first semi-conductor and the second semi-conductor; the third semi-conductor integrally includes a cylindrical portion that covers at least a portion of the insulator on the outer periphery of the terminal accommodating portion of the first semi-conductor, and a plurality of protruding pieces that protrude radially outward from the outer periphery of the cylindrical portion; at least a part of the insulator on the outer periphery of the second semi-conductor is not covered by the cylindrical portion of the third semi-conductor; A manufacturing method for manufacturing a power cable holder, wherein at least one of the plurality of protrusions has a through hole formed therethrough, a semiconductor molding step of molding the first to third semiconductors, a placement step of placing the first to third semiconductors in a mold, and an insulator molding step of injecting a thermoplastic polymer material into the mold to mold the insulator, the mold has an upper mold and a lower mold that sandwich the plurality of protruding piece portions, and at least one of the upper mold and the lower mold is provided with a protrusion to be inserted into the through hole, In the insulator molding step, the thermoplastic polymer material is injected into the mold while the plurality of protruding pieces are sandwiched between the upper mold and the lower mold and the protrusions are inserted into the through holes. A method for manufacturing a power cable holder.

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