Power cable connection device

Abstract

To provide a power cable connection device that can reduce the stress generated in a porcelain tube.SOLUTION: A power cable connection device 1 comprises a porcelain tube 22, a pipe member 21, which is arranged inside the porcelain tube 22 and into which a power cable 10 is inserted, and a mounting member 23 arranged to enclose the pipe member 21 from the periphery and fitted to the porcelain tube 22 so that a mounting surface 231d to be attached to another member is exposed from the porcelain tube 22. The mounting member 23 is divided circumferentially in at least one location.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power cable connection device. [Background technology]

[0002] Patent Document 1 discloses a power cable connection device for connecting a power cable to other electric wires, etc. The power cable connection device described in Patent Document 1 includes a porcelain bushing, a pipe member disposed inside the porcelain bushing and into which a power cable is inserted, and an embedded member surrounding the pipe member from the outer periphery and embedded in the porcelain bushing. The porcelain bushing has a first semiconductive portion at the interface with the pipe member and a second semiconductive portion at the interface with the embedded member.

[0003] The power cable connection device described in Patent Document 1 applies a release agent to the surface of the buried member facing the pipe member to prevent adhesion between the buried member and the porcelain tube, thereby preventing stress from occurring in the portion of the porcelain tube located between the buried member and the pipe member due to differences in thermal expansion coefficients among the porcelain tube, the buried member, and the pipe member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-116279 Summary of the Invention [Problem to be solved by the invention]

[0005] The power cable connection device described in Patent Document 1 has room for improvement in terms of reducing the stress generated in the porcelain bushing.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a power cable connection device that can reduce stress generated in a porcelain bushing. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a power cable connection device comprising a porcelain tube, a pipe member arranged inside the porcelain tube and into which a power cable is inserted, and an attachment member arranged to surround the pipe member from the outer periphery and provided on the porcelain tube so that an attachment surface to be attached to another member is exposed from the porcelain tube, and the attachment member is divided circumferentially at at least one location. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a power cable connection device that can reduce stress generated in a porcelain bushing. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a power cable connection device according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view of the mounting member and its surroundings in FIG. 1. [Figure 3] 4 is an enlarged view of the periphery of a mounting member in a cross-sectional view of the power cable connection device passing through a division portion in the first embodiment. FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 2. [Figure 5] FIG. 2 is a perspective view of a mounting member in the first embodiment. [Figure 6] 10 is an enlarged cross-sectional view of the periphery of a mounting member of a power cable connection device according to a second embodiment. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 5. The embodiment described below is shown as a preferred specific example for carrying out the present invention, and although various technically preferable technical matters are specifically exemplified, the technical scope of the present invention is not limited to this specific embodiment.

[0011] (Power cable connection device 1) FIG. 1 is a cross-sectional view of a power cable connection device 1 in this embodiment. As shown in FIG. 1, the power cable connection device 1 includes a main body 2, a cover 3, and a connection portion 4. The main body 2 ensures electrical insulation between the stepped stripped power cable 10 and components arranged around the power cable 10. The cover 3 covers a portion of the main body 2. The connection portion 4 is a component for connecting the power cable 10 to the outside of the power cable connection device 1. Hereinafter, the direction in which the central axis of the power cable 10 extends is referred to as the axial direction X. Furthermore, the side of the power cable 10 in the axial direction X that is connected to the connection portion 4 is referred to as the tip side X1, and the opposite side is referred to as the base side X2.

[0012] (Main body 2) The main body 2 includes a pipe member 21, a porcelain tube 22, a mounting member 23, and a flange member 24.

[0013] The pipe member 21 is made of a metal such as brass or aluminum alloy and formed into a long cylindrical shape in the axial direction X. The pipe member 21 is made of a material that is more rigid than the porcelain tube 22. The pipe member 21 is disposed on the inner periphery side of the porcelain tube 22 and reinforces the porcelain tube 22, which has flexibility.

[0014] An end portion on the tip side X1 of the pipe member 21 protrudes from the porcelain tube 22 and is electrically connected to the power cable 10 via a connection portion 4 described below. An end portion on the base side X2 of the pipe member 21 faces the mounting member 23 in the radial direction via the porcelain tube 22. The pipe member 21 is formed so that the inner diameter is larger than the outer diameter of the portion of the power cable 10 that is disposed inside the pipe member 21. This makes it easier to insert the power cable 10 inside the pipe member 21.

[0015] The porcelain bushing 22 includes an insulator 220 and semiconductive portions provided on the surface of the insulator 220 (first semiconductive portion 221, second semiconductive portion 222, and third semiconductive portion 223 in this embodiment).

[0016] The insulator 220 is made of, for example, a polymer material formed into a tubular shape and has flexibility. Examples of polymer materials that can be used for the insulator 220 include silicone rubber, ethylene propylene rubber (EPM), and ethylene propylene diene rubber (EPDM). In particular, using a material with a relatively high tear strength for the insulator 220 can more easily prevent cracks from occurring in the insulator 220. Furthermore, using a material with a relatively low modulus of elasticity for the insulator 220 can facilitate insertion of the power cable 10 into the insulator 220. In a free state before the cable is inserted into the insulator tube 22, a portion of the inner circumferential surface of the insulator tube 22 closer to the base end X2 than the pipe member 21 is smaller than the outer diameter of the power cable 10 to be inserted therein. The power cable 10 is inserted into the insulator tube 22 while expanding the portion of the inner circumferential surface of the insulator tube 22 closer to the base end X2 than the pipe member 21.

[0017] On the outer periphery of the insulator 220, annular umbrella portions 220a protruding outward are provided at a predetermined interval in a plurality of positions in the axial direction X. By forming a plurality of umbrella portions 220a on the insulator 220, it is possible to ensure a creeping distance on the outer periphery of the insulator 220, and it is possible to suppress the occurrence of creeping discharge along the surface of the insulator 220.

[0018] The insulator 220 is formed by insert molding in which the pipe member 21, the first semi-conductive portion 221, the second semi-conductive portion 222, the third semi-conductive portion 223, and the mounting member 23 are placed in a mold. As a result, the insulator 220 is formed so as to be fixed to each of the pipe member 21, the first semi-conductive portion 221, the second semi-conductive portion 222, and the third semi-conductive portion 223.

[0019] The first semiconductive portion 221, the second semiconductive portion 222, and the third semiconductive portion 223 are made of an elastic semiconductive material that is made conductive by dispersing conductive powder such as carbon in silicone rubber, EPM, EPDM, etc. The first semiconductive portion 221, the second semiconductive portion 222, and the third semiconductive portion 223 suppress electric field concentration in the surrounding areas.

[0020] The first semiconductive portion 221 is provided in the form of a film on the inner circumferential surface of the insulator 220 and is interposed between the insulator 220 and the pipe member 21. The first semiconductive portion 221 is formed in a cylindrical shape so as to surround the pipe member 21 from the outer periphery, excluding the tip end. The first semiconductive portion 221 also has a portion extending to the base end side X2 of the pipe member 21, and this portion is interposed between the insulator 220 and the power cable 10 inserted inside the pipe member 21. The first semiconductive portion 221 is formed, for example, by insert molding in which the pipe member 21 is placed in a mold. In this way, the first semiconductive portion 221 is fixed to the pipe member 21.

[0021] The second semiconductive portion 222 is formed inside the end portion of the base end side X2 of the insulator 220 and has an annular shape. The second semiconductive portion 222 comes into contact with the outer peripheral surface of the power cable 10 inserted into the porcelain tube 22. The second semiconductive portion 222 is formed by molding or the like.

[0022] The third semiconductive portion 223 is interposed between the insulator 220 and the mounting member 23 and is formed in a film shape. The third semiconductive portion 223 is formed, for example, by insert molding in which the mounting member 23 is placed in a mold. In this way, the third semiconductive portion 223 is fixed to the mounting member 23. The third semiconductive portion 223 also extends from a portion that contacts the inner circumferential surface of the mounting member 23 to the base end side X2.

[0023] Fig. 2 is an enlarged view of the periphery of the mounting member 23 in Fig. 1. Fig. 3 is an enlarged view of the periphery of the mounting member 23 in a cross-sectional view of the power cable connection device 1 passing through a dividing section 230, which will be described later. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. Fig. 5 is a perspective view of the mounting member 23. Note that in Figs. 1 to 3, the outer shape of the mounting member 23 is indicated by a dashed line.

[0024] The mounting member 23 is disposed so as to surround the end of the base end side X2 of the pipe member 21 from the outer periphery. A portion of the mounting member 23 is embedded in the porcelain tube 22. The mounting member 23 is made of a material having higher rigidity than the porcelain tube 22, such as a metal such as brass or an aluminum alloy, and is connected to a ground potential when the power cable connection device 1 is in use. The thermal expansion coefficients of the pipe member 21 and the mounting member 23 are each smaller than the thermal expansion coefficient of the insulator 220.

[0025] Here, since the porcelain tube 22, the mounting member 23, and the pipe member 21 are in close contact with each other (more specifically, fixed) unless special measures are taken, excessive stress due to the difference in the thermal expansion coefficients between them may occur in the porcelain tube 22.

[0026] Therefore, in this embodiment, the mounting member 23 is divided in the circumferential direction at least at one location. This allows the mounting member 23 to be displaceable or deformable to follow the thermal expansion and thermal contraction of the porcelain tube 22 before the mounting member 23 is fixed to the flange member 24, thereby reducing stress generated in the porcelain tube 22. In particular, when the insulator 220 is molded, the insulator 220 undergoes significant thermal contraction, which makes it easy for hardening strain to occur and for residual strain to remain in the insulator 220. However, by dividing the mounting member 23, the mounting member 23 can be displaceable or deformable to follow the porcelain tube 22, making it less likely for residual strain to remain in the porcelain tube 22.

[0027] In this embodiment, the mounting member 23 is divided in the circumferential direction at multiple locations and consists of multiple divided pieces 231. Specifically, the mounting member 23 is divided in the circumferential direction at two locations and consists of two divided pieces 231. Hereinafter, the region divided in the circumferential direction of the mounting member 23 (i.e., the region between the two divided pieces 231 in the circumferential direction of the mounting member 23) will be referred to as a divided portion 230.

[0028] The two divided portions 230 of the mounting member 23 are formed at positions 180° opposite each other in the circumferential direction. In this embodiment, the divided portions 230 are formed parallel to the axial direction X. That is, the mounting member 23 has a shape like a cylindrical member divided in half in the axial direction X. Note that the mounting member 23 only needs to be divided in the circumferential direction, and the divided portions 230 do not have to be parallel to the axial direction X. The mounting member 23 may also be divided in the circumferential direction at one location or at three or more locations. The fewer the number of divisions of the mounting member 23, the fewer the number of parts constituting the mounting member 23. The greater the number of divisions, the more likely it is that stress generated in the porcelain tube 22 will be reduced. Therefore, the number of divisions can be determined appropriately taking these factors into consideration.

[0029] In this embodiment, a gap is formed between the opposing surfaces 23a that face each other across the divided portion 230. The gap between the opposing surfaces 23a is so small that the divided pieces 231 do not come into contact with each other when the divided pieces 231 thermally expand and contract. For example, the width of the divided portion 230 (e.g., the dimension in the vertical direction in FIG. 2) is smaller than the thickness of the pipe member 21. In this embodiment, when the third semiconductive portion 223 is molded by insert molding in which the mounting member 23 is placed in a mold, part of the third semiconductive portion 223 also fills the two divided portions 230.

[0030] The divided piece 231 has an arc-shaped portion 231a formed in an arc shape, and a protruding portion 231b formed to protrude from the end of the base end side X2 of the arc-shaped portion 231a toward the outer periphery.

[0031] The third semiconductive portion 223 is fixed to the surface of the segment 231 except for the outer peripheral surface of the protruding portion 231b and the mounting surface 231d. The corners of the portion of the surface of the segment 231 that is fixed to the third semiconductive portion 223 are rounded to improve adhesion with the third semiconductive portion 223. Furthermore, the end of the inner peripheral surface of the segment 231 on the base end side X2 forms an inclined surface 231c that increases in diameter as it approaches the base end side X2. This increases the angle between the inclined surface 231c and the mounting surface 231d (described later), improving adhesion between the periphery of the inclined surface 231c on the surface of the segment 231 and the inner surface of the third semiconductive portion 223.

[0032] The surface of the base end side X2 of the split piece 231 forms a mounting surface 231d that is attached to the flange member 24. The mounting surface 231d is exposed from the porcelain tube 22 when the split piece 231 is assembled to the porcelain tube 22. The split piece 231 also has a female threaded hole 231e that opens to the mounting surface 231d. A bolt B1 for fixing the flange member 24 to the split piece 231 is screwed into the female threaded hole 231e.

[0033] The flange member 24 is formed in an annular shape. The flange member 24 is secured to the mounting member 23 by bolts B1 while overlapping the mounting surface 231d. The flange member 24 is formed with bolt insertion holes 241 through which bolts (not shown) are inserted for mounting the flange member 24 to the mounting object 100. The flange member 24 also has female threaded holes 242 that open to the surface on the base end side X2. A bolt B2 for securing the cover 3 to the flange member 24 is threaded into the female threaded hole 242. Seal portions 11a, 11b for ensuring watertightness are arranged between the flange member 24 and the mounting member 23 and between the flange member 24 and the cover 3, respectively.

[0034] (Cover 3) 1, the cover 3 is made of brass, aluminum alloy, or the like and formed into a cylindrical shape, and covers the outer periphery of the main body 2 that protrudes from the flange member 24 to the base end side X2. A cover flange 31 that protrudes to the outer periphery is formed at the end of the tip end side X1 of the cover 3. The cover flange 31 is fixed to the flange member 24 using bolts B2.

[0035] The gap between the end of the base end side X2 of the cover 3 and the power cable 10 is sealed by a sealing portion 12. The sealing portion 12 is formed by wrapping an adhesive-provided polyethylene tape, epoxy tape, or the like around the outer periphery of the power cable 10, and provides a watertight seal between the cover 3 and the power cable 10.

[0036] (Connection 4) The connection part 4 includes a conductor connecting rod 41, a high-voltage shield 42, a fixed terminal 43, and a co-fastening nut 44. The conductor connecting rod 41 has a crimping hole 411 that is open on the base end side X2. The conductor part 101 exposed from the insulating coating of the power cable 10 is inserted into the crimping hole 411, and the end of the conductor connecting rod 41 on the base end side X2 is crimped toward the conductor part 101. This connects the conductor connecting rod 41 and the power cable 10. The conductor connecting rod 41 also has a male threaded part 412 that protrudes on the tip end side X1. The male threaded part 412 passes through both the high-voltage shield 42 and the fixed terminal 43.

[0037] The high-voltage shield 42 is made of a conductor and has a cylindrical shape with a bottom that is open on the base end side X2. The high-voltage shield 42 is fitted onto the tip end portion of the pipe member 21 that protrudes from the porcelain tube 22 on the tip end side X1.

[0038] The fixed terminal 43 is plate-shaped and overlaps the high-voltage shield 42 from the tip side X1. A connection hole 431 is formed in the fixed terminal 43 for connection to an external electric wire or the like. The fixed terminal 43 and the high-voltage shield 42 are fastened together between the conductor connecting rod 41 and a fastening nut 44, whereby the fixed terminal 43, the high-voltage shield 42, and the conductor connecting rod 41 are electrically connected to one another.

[0039] (Example of using the power cable connection device 1) Next, an example of how the power cable connection device 1 of this embodiment can be used will be described. The power cable connection device 1 is attached to, for example, the roof of a railway vehicle. In this case, a wall constituting the roof of the railway vehicle, a case provided on the roof of the railway vehicle for accommodating the power cable connection device 1, or the like, becomes the attachment target 100. The power cable connection device 1 can be used for, for example, electrical connection between adjacent railway vehicles, electrical connection with a pantograph, etc.

[0040] (Functions and Effects of the First Embodiment) In the power cable connection device 1 of this embodiment, the mounting member 23 is divided in the circumferential direction at least at one location, so that the mounting member 23 can be displaced or deformed in accordance with the thermal expansion and contraction of the porcelain tube 22, thereby reducing stress generated in the porcelain tube 22.

[0041] Moreover, the mounting member 23 is divided in the circumferential direction at multiple locations and consists of multiple divided pieces 231. Therefore, the divided pieces 231 can be displaced in accordance with the thermal expansion and contraction of the porcelain tube 22, and the stress generated in the porcelain tube 22 is further reduced.

[0042] Moreover, the mounting member 23 is divided into two parts in the circumferential direction, which not only allows the mounting member 23 to be displaced following the thermal expansion and contraction of the porcelain pipe 22, but also reduces the number of parts, thereby suppressing a decrease in productivity of the power cable connection device 1.

[0043] Furthermore, a gap is formed between the opposing surfaces 23a of the mounting member 23 that face each other across the divided portion 230. Therefore, the mounting member 23 can be displaced or deformed not only in a direction that widens the width of the divided portion 230 but also in a direction that narrows the width of the divided portion 230, thereby further reducing the stress generated in the porcelain tube 22.

[0044] As described above, according to this embodiment, it is possible to provide a power cable connection device that can reduce stress generated in the porcelain bushing.

[0045] [Second embodiment] A second embodiment of the present invention will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is an enlarged cross-sectional view of the periphery of the mounting member 23 of the power cable connection device 1. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6.

[0046] This embodiment is an embodiment in which a gap seal portion 5 is further provided in addition to the first embodiment. The gap seal portion 5 prevents moisture and the like from entering the gap S between the flange member 24 and a portion of the porcelain tube 22 located on the outer periphery side of the mounting member 23. This prevents moisture and the like from entering the space inside the cover 3 from the gap S through the boundary between the flange member 24 and the mounting member 23.

[0047] The gap S is formed in the axial direction X between an opposing wall 243 (described later) of the flange member 24 and a portion of the porcelain tube 22 formed on the outer circumferential side of the mounting member 23. The opposing wall 243 is formed to protrude toward the tip side X1 of the flange member 24, faces the outer circumferential surface of the protruding portion 231b of the mounting member 23 in the radial direction, and has an annular shape. The gap S is formed around the entire circumference.

[0048] In this embodiment, the gap seal portion 5 is formed to seal the gap S from the outer periphery. The gap seal portion 5 is formed around the entire circumference and seals the gap S along the entire circumference. The gap seal portion 5 may be formed, for example, of putty, tape, or the like. When the gap seal portion 5 is formed of putty, the gap seal portion 5 may be disposed in at least a portion of the gap S, and may be applied so as to straddle the opposing wall 243 and the porcelain bushing 22 on the outer periphery of the gap S. When the gap seal portion 5 is formed of tape, the gap seal portion 5 may be wrapped around at least one circumference so as to straddle the opposing wall 243 and the porcelain bushing 22 on the outer periphery of the gap S. FIG. 6 shows an example in which the gap seal portion 5 is formed of putty and extends into the gap S. However, when the gap seal portion 5 is formed of tape, the gap seal portion 5 is not disposed in the gap S but is disposed only on the outer periphery of the gap S. Note that the gap seal portion 5 may be formed of both putty and tape, for example. In this case, for example, the gap S may be filled with putty, and the outer periphery of the putty may be further wrapped with a tape member.

[0049] In this embodiment, the presence of the gap seal portion 5 eliminates the need for a seal portion (see reference 11a in FIGS. 1 to 3) between the mounting member 23 and the flange member 24. In this embodiment, the space inside the cover 3 is watertight by the gap seal portion 5, the sealing portion (see reference numeral 12 in FIG. 1), and the seal portion 11b.

[0050] The rest is the same as in the first embodiment. It should be noted that, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previously described embodiments represent the same components, etc. as those in the previously described embodiments, unless otherwise specified.

[0051] (Functions and Effects of the Second Embodiment) The power cable connection device 1 of this embodiment further includes a gap seal portion 5 that seals the gap S. This prevents foreign matter such as moisture from entering the interior of the power cable connection device 1 (for example, the inner space of the cover) through the gap S. In addition, the second embodiment has the same functions and effects as the first embodiment.

[0052] (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 and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0053] [1] A power cable connection device 1 comprising: a porcelain tube 22; a pipe member 21 arranged inside the porcelain tube 22 and into which a power cable 10 is inserted; and an attachment member 23 arranged to surround the pipe member 21 from the outer periphery and provided on the porcelain tube 22 so that an attachment surface 231d to be attached to another member is exposed from the porcelain tube 22, wherein the attachment member 23 is divided circumferentially at at least one location.

[0054] [2] The power cable connection device 1 according to [1], wherein the mounting member 23 is divided in the circumferential direction at a plurality of locations and consists of a plurality of divided pieces 231.

[0055] [3] The power cable connection device 1 according to [2], wherein the mounting member 23 is divided into two parts in the circumferential direction.

[0056] [4] The power cable connection device 1 described in any one of [1] to [3], wherein a gap is formed between the opposing surfaces 23a that face each other across the divided portion 230 of the mounting member 23.

[0057] [5] The power cable connection device 1 described in any one of [1] to [4] further includes a flange member 24 overlapped on the mounting surface 231d of the mounting member 23 and fixed to the mounting member 23, a cover 3 located on the flange member 24 opposite the mounting member 23 side and surrounding the porcelain tube 22, and a gap sealing portion 5 that seals the gap S between the flange member 24 and a portion of the porcelain tube 22 located on the outer periphery of the mounting member 23.

[0058] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. 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. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0059] 1...Power cable connection device 10...Power cable 21...Pipe member 22...Insulator tube 23...Mounting member 23a...opposing surface 230...Divided part 231…divided piece 231d...Mounting surface 24...Flange member 3...Cover 5...Gap seal part S...gap

Claims

1. A porcelain tube and a pipe member disposed inside the porcelain tube and into which a power cable is inserted; an attachment member disposed so as to surround the pipe member from an outer circumferential side and provided on the porcelain tube such that an attachment surface to be attached to another member is exposed from the porcelain tube; The mounting member is divided in the circumferential direction at least at one location. Power cable connection device.

2. The mounting member is divided in the circumferential direction at a plurality of locations and is composed of a plurality of divided pieces. The power cable connection device according to claim 1 .

3. The mounting member is divided into two in the circumferential direction.

3. The power cable connection device according to claim 2.

4. A gap is formed between the opposing surfaces of the mounting member that face each other across the divided portion.

3. The power cable connection device according to claim 1 or 2.

5. a flange member overlapped with the mounting surface of the mounting member and fixed to the mounting member; a cover located on the opposite side of the flange member from the mounting member and surrounding the porcelain tube; a gap seal portion that seals a gap between a portion of the porcelain tube that is located on an outer circumferential side of the mounting member and the flange member, 3. The power cable connection device according to claim 1 or 2.

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