insulator

Abstract

To provide an insulator that can save weight.SOLUTION: An insulator 1 comprises: an insulator body 2 made of synthetic resin and is provided with an insertion hole 23; and a cylindrical member 3 which is coaxially inserted into the insertion hole 23, and whose outer peripheral surface is directly bonded to an inner peripheral surface of the insertion hole 23, where the insulator body 2 has: a bottomed cylindrical knob part 21 which is pinched in the case of rotating the cylindrical member 3 in a circumferential direction; a protrusion part 22 which is protruded from an inner bottom surface 21c of the knob part 21, and on a tip of which the insertion hole 23 is provided coaxially with the knob part 21; and a reinforcing part 24 which reinforces at least one of the knob part 21 and the protrusion part 22.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to insulators.

Background Art

[0002] Patent Document 1 describes an insulator that covers the connection portion between an electric wire and a rod-shaped terminal fitting. This insulator includes a porcelain insulator body provided with a through-hole-shaped hollow portion, a metal nut (cylindrical member) inserted into the hollow portion, and a cement adhesive layer interposed between the outer peripheral surface of the nut and the inner peripheral surface of the hollow portion.

[0003] The tip of the terminal fitting is provided with a hollow portion for receiving an electric wire and a male screw that screws into the female screw of the nut. One end of the electric wire is connected to the tip of the terminal fitting by being inserted into the hollow portion of the terminal fitting. With the electric wire and the terminal fitting connected, the male screw of the terminal fitting screws into the female screw of the nut. As a result, the connection portion between the electric wire and the terminal fitting can be covered with the insulator body, which is an insulator.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 does not describe weight reduction of the insulator.

[0006] An object of the present disclosure is to provide an insulator that can achieve weight reduction.

Means for Solving the Problems

[0007] The insulator according to this disclosure comprises an insulator body made of synthetic resin with an insertion hole, and a cylindrical member inserted coaxially into the insertion hole, the outer surface of which is directly joined to the inner surface of the insertion hole, wherein the insulator body has a bottomed cylindrical gripping portion that is grasped when the cylindrical member is rotated in the circumferential direction, a protruding portion that protrudes from the inner bottom surface of the gripping portion and has the insertion hole provided at its tip coaxially with the gripping portion, and a reinforcing portion that reinforces at least one of the gripping portion and the protruding portion.

[0008] In this disclosure, an insertion hole is provided in the insulator body made of synthetic resin, and a cylindrical member is inserted into the insertion hole. The outer surface of the cylindrical member is directly joined to the inner surface of the insertion hole. Therefore, the cylindrical member can be fixed to the insulator body without the need for an adhesive layer made of a material different from that of the insulator body or the cylindrical member. In other words, the number of types of materials that make up the insulator can be reduced. Consequently, material procurement and the recycling or disposal of the insulator after use are made easier.

[0009] The insulator body has a knob, a protruding part, and a reinforcing part. Insulators made of synthetic resin are lighter than porcelain insulators with a cement adhesive layer. Furthermore, the knob is a bottomed cylindrical shape. In other words, the insulator body is designed to reduce weight. As a result, the weight of the insulator can be reduced. Since the reinforcing portion reinforces at least one of the knob portion and the protruding portion, the mechanical strength of the hollowed-out insulator body can be improved. The protruding portion extends from the inner bottom surface of the knob, and the insertion hole is provided at the tip of the protruding portion. Since the cylindrical member, the insertion hole, and the knob are coaxial with each other, the cylindrical member can be accurately rotated in the circumferential direction by gripping the knob.

[0010] The insulator according to this disclosure is characterized in that the reinforcing portion is tapered, narrowing from the inner bottom surface side of the knob portion toward the opening side of the knob portion.

[0011] In this disclosure, the reinforcing portion is tapered. The reinforcing section tapers from the inner bottom surface of the knob towards the opening. Therefore, the internal space of the knob is narrower closer to the inner bottom surface and wider closer to the opening. Furthermore, the tapered surface of the reinforcing section can be used as a fluid guide surface to direct liquid that has entered the internal space of the knob to the opening. As a result, it is possible to prevent liquid from accumulating in the internal space of the knob. Since the internal space of the knob is narrower closer to the inner bottom surface, it is possible to suppress the accumulation of non-liquid objects (insects, dust, etc.) that enter the internal space of the knob.

[0012] The insulator according to this disclosure is characterized in that a liquid guide surface or liquid guide channel for guiding liquid that has entered the internal space of the knob portion to the opening of the knob portion is provided on the reinforcing portion or the inner surface of the knob portion.

[0013] In this disclosure, a liquid guide surface or liquid guide channel is provided on the reinforcing portion (or the inner surface of the knob portion). Liquid that enters the internal space of the knob portion is guided to the opening of the knob portion via the liquid guide surface or liquid guide channel. Therefore, it is possible to prevent liquid from accumulating in the internal space of the knob portion.

[0014] The insulator according to this disclosure is characterized in that the fluid conduit has a groove-like shape extending from the inner bottom surface side of the knob portion toward the opening side of the knob portion.

[0015] In this disclosure, since the fluid conduit is grooved, liquid that has entered the internal space of the knob easily collects in the fluid conduit. Since the fluid conduit extends from the inner bottom surface side of the knob toward the opening side, the liquid that has collected in the fluid conduit can be easily guided to the opening of the knob.

[0016] The insulator according to this disclosure is characterized in that at least a portion of the reinforcing portion is located between the peripheral edge of the opening of the knob portion and the tip of the protruding portion.

[0017] In the present disclosure, at least a part of the reinforcing portion is located between the peripheral edge of the knob portion opening and the tip of the protruding portion. Therefore, the gap between the peripheral edge of the knob portion opening and the tip of the protruding portion can be narrowed by the reinforcing portion, so that the intrusion of liquid or non-liquid objects into the internal space of the knob portion can be suppressed. Further, since there is no need to provide a member separate from the reinforcing portion for the purpose of narrowing the gap between the peripheral edge of the knob portion opening and the tip of the protruding portion, the structure of the insulator can be simplified.

[0018] The insulator according to the present disclosure is characterized in that a plurality of the reinforcing portions are provided, and the plurality of the reinforcing portions are spaced apart in the circumferential direction of the knob portion.

[0019] In the present disclosure, since a plurality of reinforcing portions are spaced apart in the circumferential direction of the knob portion, the insulator body can be designed to be uniformly reinforced in the circumferential direction of the knob portion. By the plurality of reinforcing portions, the internal space of the knob portion can be narrowed to suppress the intrusion and retention of non-liquid objects.

[0020] [Appendix] The insulator according to the present disclosure is characterized in that the peripheral wall of the knob portion is inclined in a direction of increasing diameter from the side of the bottom wall of the knob portion toward the side of the opening of the knob portion.

[0021] In the present disclosure, the peripheral wall of the knob portion is inclined in a direction of increasing diameter from the bottom wall side toward the opening side. In other words, the knob portion tapers from the opening side toward the bottom wall side. Therefore, the internal space of the knob portion is narrower closer to the inner bottom surface and wider closer to the opening. Further, the inner peripheral surface of the knob portion can be used as a liquid guiding surface for guiding the liquid that has entered the internal space of the knob portion to the opening of the knob portion. As a result of the above, it is possible to prevent the liquid from staying in the internal space of the knob portion. Since the internal space of the knob portion is narrower in the portion closer to the inner bottom surface, it is possible to suppress the non-liquid object that has entered the internal space of the knob portion from staying in the internal space of the knob portion.

[0022] In addition, the outer peripheral surface of the knob portion can be used as a guide surface for guiding the liquid adhering to the outer peripheral surface of the knob portion away from the opening of the knob portion. Therefore, it is possible to suppress the intrusion of liquid into the internal space of the knob portion.

[0023] The insulator according to the present disclosure is characterized in that the depth of the insertion hole is larger than the axial length of the portion inserted into the insertion hole of the cylindrical member.

[0024] In the present disclosure, the depth of the insertion hole is larger than the axial length of the portion inserted into the insertion hole of the cylindrical member. So to speak, the protruding portion is hollowed out. Therefore, the insulator can be further lightened.

[0025] The insulator according to the present disclosure is characterized in that the protruding portion has a columnar shape whose axial direction is along the axial direction of the knob portion, and the reinforcing portion extends over the inner bottom surface and the inner peripheral surface of the knob portion and the outer peripheral surface of the protruding portion.

[0026] In the present disclosure, since the reinforcing portion extends over the inner bottom surface and the inner peripheral surface of the knob portion and the outer peripheral surface of the columnar protruding portion, both the knob portion and the protruding portion can be reinforced.

[0027] The insulator according to the present disclosure is characterized in that the reinforcing portion has a protruding cylinder protruding from the inner bottom surface of the knob portion, and the protruding portion is arranged inside the protruding cylinder.

[0028] In the present disclosure, the reinforcing portion has a protruding cylinder. The protruding cylinder protrudes from the inner bottom surface of the knob portion, and the protruding portion is arranged inside the reinforcing portion. Therefore, the bottom wall of the knob portion can be reinforced over the entire circumference in the circumferential direction by the protruding cylinder.

[0029] The insulator according to the present disclosure is characterized in that an anti-slip portion is provided on the outer peripheral surface of the knob portion. <00​​​ [Effects of the Invention]

[0031] The insulators of this disclosure can be made lighter. [Brief explanation of the drawing]

[0032] [Figure 1] This is an external view of the insulator according to Embodiment 1. [Figure 2] This is a cross-section of the insulator. [Figure 3] This is a cross-sectional view of a bushing equipped with an insulator. [Figure 4] This is an external view of the insulator according to Embodiment 2. [Figure 5] This is an external view of the insulator according to Embodiment 3. [Figure 6] This is an external view of the insulator according to Embodiment 4. [Modes for carrying out the invention]

[0033] The embodiments of this disclosure will be described below.

[0034] Embodiment 1. Figure 1 is an external view of an insulator according to Embodiment 1. In the figure, 1 is an insulator, Figure 1A is a front view of insulator 1, and Figure 1B is a view taken along line II in Figure 1A. The insulator 1 comprises an insulator body 2 and a cylindrical member 3. The insulator body 2 is an insulator made of synthetic resin (thermoplastic resin or thermosetting resin).

[0035] Figure 2 is a cross-sectional view of insulator 1. Figure 2A is a cross-sectional view taken along line II-II in Figure 1B, and Figure 2B is a cross-sectional view taken along line III-III in Figure 1B. As shown in Figures 1 and 2, the insulator body 2 integrally comprises a large-diameter, bottomed cylindrical knob portion 21 and a small-diameter, cylindrical projection portion 22. The knob portion 21 and the projection portion 22 are coaxial with each other. In Figures 1A and 2, the insulator 1 is shown with the axial lengths of the knob portion 21 and the projection portion 22 oriented left and right, respectively, and the bottom wall / opening of the knob portion 21 positioned on the left and right sides respectively.

[0036] The peripheral wall of the knob portion 21 is inclined in a direction that expands in diameter from the bottom wall side of the knob portion 21 toward the opening side of the knob portion 21 (from left to right in the diagram). The inclination angle of the peripheral wall of the knob portion 21 with respect to the central axis of the knob portion 21 is about 2°, but is not limited to this, and for example, it can be about 0.5 to 5°. Anti-slip material 211 is provided on the outer circumferential surface of the knob portion 21. In this embodiment, the anti-slip material 211 has a configuration in which recesses 21a and protrusions 21b are alternately arranged in the circumferential direction of the knob portion 21, but is not limited to this configuration.

[0037] The protruding portion 22 protrudes to the right from the inner bottom surface 21c of the knob portion 21. The amount of protrusion of the projection 22 (the distance from the inner bottom surface 21c of the knob portion 21 to the tip of the projection 22) is appropriately greater than the amount of protrusion of the peripheral wall of the knob portion 21 (the distance from the inner bottom surface 21c of the knob portion 21 to the tip of the peripheral wall). For example, the portion of the projection 22 from the tip to about 20% to 40% of its total length is exposed to the outside of the knob portion 21 through the opening of the knob portion 21. As shown in Figure 2A, an insertion hole 23 is provided on the tip surface of the protrusion 22. The insertion hole 23 is a non-through hole with a circular cross-section and extends along the entire length of the protrusion 22. The insertion hole 23 is also coaxial with the protrusion 22.

[0038] The cylindrical member 3 is an insert nut, having a flange 31 at one end in the axial direction, and having anti-slip irregularities on its outer surface (for example, a cross-patterned or flat pattern created by knurling; not shown). The cylindrical member 3 is made of metal, for example, but is not limited to this. The cylindrical member 3 is inserted coaxially into the insertion hole 23 such that the flange 31 is located outside the insertion hole 23. The outer surface of the cylindrical member 3 is directly joined to the inner surface of the insertion hole 23. The axial length of the portion of the cylindrical member 3 inserted into the insertion hole 23 is less than the depth of the insertion hole 23, and is approximately half the depth of the insertion hole 23.

[0039] Insulator 1 constitutes the bushing 4, which will be described next. Figure 3 is a cross-sectional view of a bushing 4 equipped with an insulator 1. The bushing 4 includes an insulator 1, an insulating tube 41, and a terminal fitting 42. Figure 3 shows the vicinity of one end 41a of the insulator tube 41 in the axial direction. The inner diameter of the insulator tube 41 is larger than the outer diameter of the protrusion 22 of the insulator body 2. A notch 411 is provided at one end 41a of the insulator tube 41. The insulator 41 is made of an insulating material and penetrates the side wall of a case, for example, of a transformer or switch (not shown), with one end 41a of the insulator 41 located outside the case. The insulator 41 is arranged so that the notch 411 faces downward and its axial length is horizontal.

[0040] The terminal fitting 42 is rod-shaped and passes coaxially through the insulator tube 41. At one end of the terminal fitting 42, a large-diameter disc portion 420, a small-diameter cylindrical first shaft portion 421, a large-diameter cylindrical bolt portion 422, a small-diameter cylindrical second shaft portion 423, and a large-diameter cylindrical connecting portion 424 are arranged coaxially in this order from one end to the other. The disc portion 420 and the first shaft portion 421 are on the outside of the insulator tube 41. The bolt portion 422 extends inside and outside the insulator tube 41 through the opening at one end 41a of the insulator tube 41. The second shaft portion 423 and the connecting portion 424 are on the inside of the insulator tube 41. A male thread is provided on the circumferential surface of the bolt portion 422, and this male thread corresponds to the female thread of the cylindrical member 3. The second shaft portion 423 is provided with a through hole 425 perpendicular to the axial length direction of the second shaft portion 423. One opening of the through hole 425 is directed toward the notch 411 of the insulator tube 41.

[0041] The electric wire 5 is a covered electric wire in which the conductor 51 is covered with an insulator. The conductor 51 is exposed at one end of the electric wire 5. The electric wire 5 is inserted inside the insulator tube 41 so that the conductor 51 passes through the through hole 425, and extends both inside and outside the insulator tube 41 through the notch 411.

[0042] The disc portion 420 and the first shaft portion 421 are inserted into the internal space of the insertion hole 23 through the inside of the cylindrical member 3, and the bolt portion 422 is screwed into the cylindrical member 3. As a result, the terminal fitting 42 penetrates the cylindrical member 3. The conductor 51 is sandwiched between the flange 31 of the cylindrical member 3, the inner circumferential surface of the through hole 425, and the end face of the connecting portion 424 that is closer to the bolt portion 422. As a result, the conductor 51 comes into contact with the second shaft portion 423 and the connecting portion 424, so that the terminal fitting 42 and the electric wire 5 are electrically connected to each other.

[0043] It is desirable that a spring washer 43 and a flat washer 44 (referred to by the dashed lines in the figure) be interposed between the flange 31 and the conductor 51. The flat washer 44 is interposed between the spring washer 43 and the conductor 51, and the spring washer 43 biases the conductor 51 to press against the connection part 424 via the flat washer 44. For clarity of the figure, in Figure 3 the cylindrical member 3, terminal fitting 42, spring washer 43, flat washer 44, and conductor 51 are shown separated from each other.

[0044] The axial length of the portion of the terminal fitting 42 inserted into the insertion hole 23 is smaller than the depth of the insertion hole 23. Neither the cylindrical member 3 nor the terminal fitting 42 is present in the portion of the internal space of the insertion hole 23 closest to the inner bottom surface. In this embodiment, approximately 40% of the internal space of the insertion hole 23 is empty space for weight reduction.

[0045] The insulator 1 is detachable from the terminal fitting 42. The insulator 1 can be easily attached and detached by hand by an operator who grasps the handle 21 and rotates the insulator 1 in the circumferential direction of the handle 21. The handle 21 and the cylindrical member 3 are coaxial with each other, and a non-slip surface 211 is provided on the outer surface of the handle 21. Therefore, it is easy to grasp the handle 21 and accurately rotate the cylindrical member 3 in the circumferential direction to attach and detach the insulator from the bolt portion 422 of the terminal fitting 42.

[0046] When screwing the cylindrical member 3 and the bolt portion 422 together, the worker rotates the knob portion 21 and tightens it with a load corresponding to the screw diameter. At this time, the protruding portion 22 is inserted into the inside of the insulator tube 41 through the opening of one end portion 41a of the insulator tube 41. The opening edge of one end portion 41a of the insulator tube 41 and the opening edge of the knob portion 21 face each other in the axial direction with a small gap in between. Since the connection between the terminal fitting 42 and the electric wire 5 is covered by the peripheral wall of the insulator tube 41 and the insulator body 2 of the insulator 1, the connection between the terminal fitting 42 and the electric wire 5 can be protected from collision with foreign objects or electrical contact.

[0047] Bushing 4 is preferably weather-resistant, especially when used outdoors. Regarding insulator 1, since the insulator body 2 is susceptible to exposure to ultraviolet rays and wind and rain, a weather-resistant protective layer may be provided on the surface of the insulator body 2. Alternatively, the insulator body 2 itself may be made of a weather-resistant synthetic resin. If the insulator 1 is weather-resistant, it can be used for a long period even outdoors. Therefore, since there is no need to frequently replace the insulator 1, the environmental burden can be reduced.

[0048] With the insulator 1 described above, the outer surface of the cylindrical member 3 is directly joined to the inner surface of the insertion hole 23. Therefore, the cylindrical member 3 can be fixed to the insulator body 2 without the need for an adhesive layer made of a material different from both the material constituting the insulator body 2 and the material constituting the cylindrical member 3. In other words, the number of types of materials constituting the insulator 1 can be reduced. Therefore, the procurement of materials and the recycling or disposal of the insulator 1 after use are facilitated. In particular, if the insulator body 2 is made of thermoplastic resin, the insulator body 2 can be softened or melted by heating during recycling or disposal, making it easy to dismantle the insulator 1.

[0049] The synthetic resin insulator body 2 is lighter than the porcelain insulator body, which has a cement adhesive layer attached to it. Moreover, the knob portion 21 is a bottomed cylindrical shape, and an empty space is formed in the protruding portion 22. In other words, the insulator body 2 has a structure in which both the knob portion 21 and the protruding portion 22 have been lightened. As a result, the weight of the insulator 1 can be reduced. Therefore, the work of transporting the insulator 1 and the work of attaching and detaching the insulator 1 to the terminal fitting 42 are easier.

[0050] To reinforce the hollowed-out knob portion 21 and protruding portion 22, the insulator body 2 has eight reinforcing portions 24, as shown in Figures 1 to 3. Each reinforcing portion 24 is integrally provided with the knob portion 21 and the protruding portion 22, respectively. The eight reinforcing portions 24 are arranged at equal intervals in the circumferential direction of the knob portion 21. Each reinforcing portion 24 extends from the inner bottom surface 21c and inner circumferential surface of the knob portion 21 to the outer circumferential surface of the protruding portion 22.

[0051] The reinforcing portion 24 is a plate oriented perpendicular to the circumferential direction of the knob portion 21, and is roughly trapezoidal in shape. Three sides of the trapezoid, excluding the hypotenuse, are in contact with the inner bottom surface 21c and inner circumferential surface of the knob portion 21 and the outer circumferential surface of the protruding portion 22. The hypotenuse of the trapezoid extends from the tip of the circumferential wall of the knob portion 21 to the vicinity of the tip of the protruding portion 22. In other words, at least a portion of the reinforcing portion 24 is located between the periphery of the opening of the knob portion 21 and the tip of the protruding portion 22. The reinforcing portion 24 has a tapered shape that narrows to the right when viewed from the outside. The taper angle of the reinforcing portion 24 is about 0.5 to 5°, preferably 3° or less.

[0052] As described above, the reinforcing portion 24 can reinforce both the knob portion 21 and the protruding portion 22, thereby improving the mechanical strength of the weight-reduced insulator body 2. Moreover, since the eight reinforcing portions 24 are equally distributed in the circumferential direction of the knob portion, the insulator body 2 is evenly reinforced in the circumferential direction of the knob portion 21. Note that the number of reinforcing portions 24 is not limited to eight. Alternatively, multiple reinforcing portions 24 may be arranged at uneven intervals in the circumferential direction of the knob portion 21. Even in this case, the insulator body 2 can be designed to be evenly reinforced in the circumferential direction of the knob portion 21.

[0053] The reinforcing portion 24 tapers from the inner bottom surface 21c side of the knob portion 21 toward the opening side, and the knob portion 21 tapers from the opening side toward the bottom wall side. As a result, the internal space of the knob portion 21 is narrower closer to the inner bottom surface and wider closer to the opening. Even if the axial length direction of the knob portion 21 is horizontal, the upward tapered surface of the reinforcing portion 24 is inclined so that it is located lower the closer it is to the opening of the knob portion 21. Such a tapered surface functions as a fluid guide surface to lead liquid that has entered the internal space of the knob portion 21 to the opening of the knob portion 21. Similarly, the lower part of the inner circumferential surface of the knob portion 21 is inclined so that it is located lower the closer it is to the opening of the knob portion 21, and thus functions as a fluid guide surface to lead liquid that has entered the internal space of the knob portion 21 to the opening of the knob portion 21. As a result, it is possible to prevent liquid from accumulating in the internal space of the knob portion 21.

[0054] Furthermore, the upper part of the outer surface of the knob portion 21 is inclined so that it is positioned higher the closer it is to the opening of the knob portion 21. This acts as a guide surface that directs liquid adhering to the outer surface of the knob portion 21 away from the opening of the knob portion 21. Therefore, it is possible to suppress the entry of liquid into the internal space of the knob portion 21.

[0055] The eight reinforcing sections 24 divide the internal space of the knob section 21 into eight sections. Each divided space is narrow. Moreover, the individual divided spaces become narrower the closer they are to the inner bottom surface of the knob section 21. Therefore, it is possible to prevent non-liquid objects (insects, dust, etc.) from entering the internal space of the knob section 21, and to prevent any non-liquid objects that do enter from accumulating in the internal space of the knob section 21.

[0056] A portion of the reinforcing part 24 (the part that protrudes to the right from the opening of the knob part 21; hereinafter referred to as the gap-reducing part) is located between the opening periphery of the knob part 21 and the tip of the protruding part 22. When the bushing 4 is constructed using the insulator 1, the gap-reducing part of the reinforcing part 24 can narrow the gap between the opening periphery of the knob part 21 and the outer circumferential surface of the protruding part 22, as well as the gap between the opening periphery of one end 41a of the insulator tube 41 and the outer circumferential surface of the protruding part 22. Therefore, it is possible to suppress the intrusion of liquid or non-liquid objects into the internal space of the knob part 21. Furthermore, since it is not necessary to provide a separate member from the reinforcing part 24 for this purpose, the construction of the insulator 1 can be simplified.

[0057] When forming the insulator body 2 of the insulator 1 as described above, for example, the worker sets the cylindrical member 3 in a mold for molding the insulator body 2, then injects synthetic resin into the mold and allows it to harden. As a result, the outer surface of the cylindrical member 3 can be directly joined to the inner surface of the insertion hole 23. Alternatively, the worker pushes the cylindrical member 3 into the portion that will become the insertion hole 23 of the synthetic resin before the synthetic resin injected into the mold hardens, and allows the synthetic resin to harden. When using thermoplastic resin, the worker may soften the insulator body 2 formed using a mold or 3D printer by heating, and before the softened thermoplastic resin hardens, push the cylindrical member 3 into the portion that will become the insertion hole 23 of the thermoplastic resin, and allow the thermoplastic resin to harden.

[0058] The insertion hole 23 does not need to be coaxial with the knob portion 21, but it does not need to be coaxial with the protruding portion 22. The cylindrical member 3 does not have to be an insert nut with anti-slip grooves. The cylindrical member 3 may also be configured without a flange 31. The insulator tube 41 is not limited to being arranged so that its axial length is horizontal; it may also be arranged so that one end 41a of the insulator tube 41 is higher than the other end, and its axial length is oblique or vertical.

[0059] The fluid guide surface provided on the reinforcing portion 24 is not limited to the tapered surface of the tapered reinforcing portion 24. For example, if the flat reinforcing portion 24 is inclined with respect to the horizontal plane such that one surface is located lower as it approaches the opening of the knob portion 21, the upper surface of the reinforcing portion 24 can function as the fluid guide surface. The reinforcing portion 24 may reinforce only one of the knob portion 21 or the protruding portion 22. Furthermore, multiple reinforcing portions 24 may include those that reinforce only the knob portion 21 and those that reinforce only the protruding portion 22.

[0060] Embodiment 2. The insulator 1 of this embodiment is substantially the same as the insulator 1 of Embodiment 1, except for the configuration of the reinforcing portion 24. The insulator 1 of this embodiment provides substantially the same effects and benefits as the insulator 1 of Embodiment 1. The differences from Embodiment 1 will be explained below, and other components identical to those in Embodiment 1 will be denoted by the same reference numerals and their descriptions will be omitted.

[0061] Figure 4 is an external view of the insulator 1 according to Embodiment 2. In the case of the insulator 1 shown in Figure 4A, multiple fluid passages 241 are provided on each side of the reinforcing portion 24, similar to the reinforcing portion 24 of Embodiment 1. The multiple fluid passages 241 provided on the same surface of the reinforcing portion 24 are aligned radially with the knob portion 21 and are parallel to each other. Each fluid passage 241 is a narrow groove extending from the inner bottom surface 21c side of the knob portion 21 toward the opening side of the knob portion 21.

[0062] The fluid conduit 241 is grooved. Liquid that has entered the internal space of the knob 21 tends to collect in the upward-opening fluid conduit 241. The liquid collected in the fluid conduit 241 flows along the fluid conduit 241 from the inner bottom surface 21c side of the knob 21 toward the opening side and is guided to the opening of the knob 21. Therefore, it is possible to prevent liquid from accumulating in the internal space of the knob 21. Note that the number and width of the fluid conduit 241 are not limited to those shown in Figure 4A. Also, the fluid conduit 241 may be provided on the inner circumferential surface of the knob 21.

[0063] In the case of the insulator 1 shown in Figure 4B, the reinforcing portion 24 is corrugated, and multiple fluid conduits 242 are arranged in parallel in the radial direction of the knob portion 21 on each side of the reinforcing portion 24. Each fluid conduit 242 is a wide recessed groove that extends toward the opening of the knob portion 21 on the inner bottom surface 21c of the knob portion 21. The fluid conduits 242 have the same effects as the fluid conduits 241.

[0064] In both the insulator 1 shown in Figure 4A and the insulator 1 shown in Figure 4B, fluid guide channels 241 and 242 are provided on both sides of each of the eight equally spaced reinforcing parts 24. Therefore, regardless of which part of the knob part 21 is facing upward in the circumferential direction, the insulator 1 can guide any liquid that has entered the internal space of the knob part 21 to the opening of the knob part 21 via the fluid guide channels 241 and 242. The fluid conduit provided in the reinforcing portion 24 is not limited to fluid conduits 241 and 242, but may also be, for example, a through hole provided in the lower part of the reinforcing portion 24. The liquid that passes through the through hole-shaped fluid conduit collects, for example, at the lower part of the inner circumferential surface of the knob portion 21 and flows down toward the opening of the knob portion 21.

[0065] Next, embodiments 3 and 4 will be described. The insulator 1 of embodiments 3 and 4 is substantially the same as the insulator 1 of embodiment 1, except that the insulator body 2 has reinforcing parts 25 and 26 instead of reinforcing part 24. The insulator 1 of embodiments 3 and 4 provides substantially the same effects and benefits as the insulator 1 of embodiment 1. In the following, the differences from embodiment 1 will be explained, and other components identical to those of embodiment 1 will be denoted by the same reference numerals and their descriptions will be omitted.

[0066] Embodiment 3. Figure 5 is an external view of the insulator 1 according to Embodiment 3. Figure 5A is a front view of the insulator 1, and Figure 5B is a view taken along the VV line in Figure 5A. The insulator body 2 has a reinforcing section 25. The reinforcing section 25 has a protruding cylinder 251 and eight ribs 252, 253.

[0067] The protruding cylinder 251 is integrally provided with the knob portion 21. The protruding cylinder 251 is cylindrical in shape and protrudes coaxially to the right from the inner bottom surface 21c of the knob portion 21. The protruding portion 22 is located inside the protruding cylinder 251. The inner circumferential surface of the knob portion 21 and the outer circumferential surface of the protruding cylinder 251 are spaced appropriately apart from each other. The inner circumferential surface of the protruding cylinder 251 and the outer circumferential surface of the protruding portion 22 are spaced appropriately apart from each other. The protruding cylinder 251 can reinforce the bottom wall of the knob portion 21 around its entire circumference.

[0068] The amount of protrusion of the protruding cylinder 251 (the distance from the inner bottom surface 21c of the knob portion 21 to the tip of the protruding cylinder 251) is appropriately larger than the amount of protrusion of the peripheral wall of the knob portion 21, and less than or equal to the amount of protrusion of the protruding portion 22. A part of the protruding cylinder 251 (specifically, the part that protrudes to the right from the opening of the knob portion 21) provides the same effect as the gap-reducing portion of the reinforcing portion 24 in Embodiment 1.

[0069] Ribs 252 and 253 have the same configuration as reinforcement section 24. The differences from reinforcement section 24 will be explained below. Each rib 252 is integrally provided on the knob portion 21 and the protruding cylinder 251, respectively. The rib 252 is a rectangular plate, with three sides in contact with the inner bottom surface 21c and inner circumferential surface of the knob portion 21 and the outer circumferential surface of the protruding cylinder 251. The length of the rib 252 in the left-right direction is less than or equal to the amount of protrusion of the circumferential wall of the knob portion 21. The rib 252 can reinforce the knob portion 21 and the protruding cylinder 251.

[0070] Each rib 253 is integrally provided on the knob portion 21, the projection portion 22, and the projection cylinder 251, respectively. The rib 253 is a rectangular plate, with three sides in contact with the inner bottom surface 21c of the knob portion 21, the outer surface of the projection portion 22, and the inner surface of the projection cylinder 251. The length of the rib 253 in the left-right direction of the knob portion 21 is less than or equal to the projection amount of the projection cylinder 251. The rib 253 can reinforce the knob portion 21, the projection portion 22, and the projection cylinder 251.

[0071] The reinforcing section 25 divides the internal space of the knob section 21 into 16 sections. Each of these divided spaces is very narrow. Therefore, it is possible to prevent non-liquid objects from entering the internal space of the knob section 21, and also to prevent any non-liquid objects that have entered from accumulating in the internal space of the knob section 21.

[0072] Embodiment 4. Figure 6 is an external view of the insulator 1 according to Embodiment 4. Figure 6A is a front view of the insulator 1, and Figure 6B is a view taken along the line VI-VI in Figure 6A. The insulator body 2 has eight reinforcing parts 26. Each reinforcing part 26 is integrally provided with the knob part 21 and the protruding part 22, respectively. The eight reinforcing portions 26 are arranged at equal intervals in the circumferential direction of the knob portion 21. Each reinforcing portion 26 extends from the inner bottom surface 21c and inner circumferential surface of the knob portion 21 to the outer circumferential surface of the protruding portion 22.

[0073] The reinforcing portion 26 is cylindrical in shape and protrudes to the right from the inner bottom surface 21c of the knob portion 21, with the axial direction of the reinforcing portion 26 being parallel to the axial direction of the knob portion 21. A portion of the circumferential direction of the reinforcing portion 26 is in contact with the inner circumferential surface of the knob portion 21, and the other portion of the circumferential direction of the reinforcing portion 26 is in contact with the outer circumferential surface of the protruding portion 22. The reinforcing portion 26 described above can reinforce both the knob portion 21 and the protruding portion 22, similar to the case of the reinforcing portion 24 in Embodiment 1. Two adjacent reinforcing parts 26 may also be in contact with each other in the circumferential direction. In this case, the reinforcing parts 26 can reinforce each other.

[0074] The amount of protrusion of the reinforcing portion 26 (the distance from the inner bottom surface 21c of the knob portion 21 to the tip of the reinforcing portion 26) is appropriately larger than the amount of protrusion of the peripheral wall of the knob portion 21, and less than or equal to the amount of protrusion of the protruding portion 22. A part of the reinforcing portion 26 (specifically, the part that protrudes to the right from the opening of the knob portion 21) provides the same effect as the gap-reducing portion of the reinforcing portion 24 in Embodiment 1. The eight reinforcing parts 26 divide the internal space of the knob part 21 into 16 sections, so, similar to the case of the reinforcing part 25 in Embodiment 3, the intrusion and accumulation of non-liquid substances can be suppressed.

[0075] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is intended to include, but not in the sense described above, the equivalents of the claims and all modifications within the claims. The constituent elements (technical features) disclosed in each embodiment are combinable with each other, and new technical features can be formed by these combinations. Furthermore, the independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference. Moreover, while the claims use a multi-claim format in which claims refer to two or more other claims (multi-claim format), the claims are not limited to this. A multi-claim format in which at least one multi-claim is referenced (multi-multi-claim format) may also be used. [Explanation of Symbols]

[0076] 1 Insulator; 2 Insulator body; 21 Knob; 21c Inner bottom surface; 22 Protruding part; 23 Insertion hole; 24,25,26 Reinforcement parts; 241,242 Fluid conduit; 3 Cylindrical member

Claims

1. An insulator body made of synthetic resin with an insertion hole, A cylindrical member is inserted coaxially into the aforementioned insertion hole, and its outer surface is directly joined to the inner surface of the aforementioned insertion hole. Equipped with, The insulator body is, The cylindrical member has a bottomed, cylindrical gripping portion that is grasped when the cylindrical member is rotated in the circumferential direction, A protruding portion that extends from the inner bottom surface of the knob portion, with the insertion hole at its tip provided coaxially with the knob portion, A reinforcing portion that reinforces at least one of the aforementioned knob portion and the aforementioned protruding portion. An insulator characterized by having [a certain feature].

2. The insulator according to claim 1, characterized in that the reinforcing portion is tapered, narrowing from the inner bottom surface side of the knob portion toward the opening side of the knob portion.

3. The insulator according to claim 1, characterized in that a liquid guide surface or liquid guide channel for guiding liquid that has entered the internal space of the knob to the opening of the knob is provided on the reinforcing part or the inner surface of the knob.

4. The insulator according to claim 3, characterized in that the fluid passage has a concave ridge shape extending from the side of the inner bottom surface of the knob toward the side of the opening of the knob.

5. The insulator according to any one of claims 1 to 4, characterized in that at least a portion of the reinforcing portion is located between the peripheral edge of the opening of the knob portion and the tip of the protruding portion.

6. Multiple reinforcing sections are provided, The insulator according to any one of claims 1 to 4, characterized in that the plurality of reinforcing parts are spaced apart in the circumferential direction of the knob part.

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