Patent Description:
In a switching device used for grid operation of power receiving/distributing equipment or the like, it is necessary to inhibit remaining of gas, for preventing reduction in insulation performance of the bus connection portion. Conventionally, in assembly of the bus connection portion, for example, a gas removing tool having an exhaust hole is inserted into the bus connection portion, and while a tightening member such as a screw is rotated, gas compressed in the bus connection portion is exhausted through the exhaust hole, thereby preventing remaining of the gas (see, for example, Patent Document <NUM>).

Patent Document discloses another example of the use of exhaust tools on insulated bus assemblies.

However, in a process when the gas removing tool is inserted between an insulating plug and a connector of the bus connection portion and the insulating plug is rotated and fitted into the connector, the gas removing tool moves so as to follow rotation of the insulating plug, so that the gas removing tool is displaced to hamper gas passage through the exhaust hole, thus causing a problem that the gas cannot be exhausted sufficiently.

The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide an exhaust tool and a switching device manufacturing method using the exhaust tool that, in assembly of a bus connection portion of a switching device, prevent displacement of a tool used for exhausting gas, and efficiently exhaust gas between a connector and an insulating plug, thereby inhibiting remaining of the gas.

Therefore, there are provided an exhaust tool and a switching device manufacturing method according to the independent claims.

According to the present disclosure, by the through-hole-shaped holding portion, movement of the exhaust tool is restricted and a gas passage can be ensured, and by severing the cut-in portion not penetrated, the body portion of the exhaust tool can be extracted from the electric apparatus. Thus, gas can be efficiently exhausted while the bus connection portion is assembled.

Hereinafter, embodiment <NUM> will be described with reference to the drawings.

<FIG> is a schematic view of a lateral side cross-section of a switching device according to embodiment <NUM>. In <FIG>, a switching device <NUM> is a switchgear used for grid operation of power receiving/distributing equipment for power of an electrical substation, for example. In a housing <NUM> of the switching device <NUM>, for example, a disconnector <NUM>, a disconnector operation mechanism <NUM> as an operation mechanism therefor, a circuit breaker <NUM>, a circuit breaker operation mechanism <NUM> as an operation mechanism therefor, a ground switch <NUM>, an arrester <NUM>, and a current transformer <NUM>, are arranged. When abnormal current flows due to a lightning strike or the like, the circuit breaker <NUM> interrupts a circuit, to prevent the abnormal current from flowing through a grid and protect electric apparatuses connected to the switching device <NUM>. The switching device <NUM> is provided with a bus connection portion <NUM>, and in an example in <FIG>, the bus connection portion <NUM> is connected to a bushing <NUM>, which is then connected to the disconnector <NUM> in the housing <NUM>. A first electric apparatus <NUM> and a second electric apparatus <NUM> described later are, at least partially, included in the bus connection portion <NUM>.

<FIG> schematically shows the bus connection portion <NUM>. The first electric apparatus <NUM> of the bus connection portion <NUM> includes a bus <NUM>, a connector <NUM>, and the bushing <NUM>. For example, the bus <NUM> and the bushing <NUM> are inserted into the connector <NUM>, thus forming the first electric apparatus <NUM>. The first electric apparatus <NUM> is connected via the bushing <NUM> to an electric apparatus in the housing <NUM> of the switching device <NUM>. The bus <NUM> is formed by a bus conductor <NUM> and an insulation shield <NUM> surrounding the periphery of the bus conductor <NUM>. The bushing <NUM> includes a first tightening portion <NUM> which is conductive, divided terminals <NUM>, and a conductive member <NUM>. The first tightening portion <NUM> is a stud bolt having external threads on both sides, for example. The bushing <NUM> is inserted into an opening <NUM> of the connector <NUM> in an arrow direction in <FIG>, and then the bus <NUM> is inserted into an opening <NUM> of the connector <NUM> in an arrow direction in <FIG>. When the bus <NUM> is inserted into the connector <NUM>, an end of the bus conductor <NUM> is held by the divided terminals <NUM> of the bushing <NUM>, and a side surface of the bus conductor <NUM> is held by the conductive member <NUM>.

The second electric apparatus <NUM> includes an insulating plug <NUM>, and for example, a ground apparatus (not shown). The insulating plug <NUM> serves to make insulation between the bus <NUM> and the second electric apparatus <NUM>. The insulating plug <NUM> has, therein, a second tightening portion <NUM> which is conductive. The second tightening portion <NUM> has an internal thread to be fitted to the first tightening portion <NUM>. After the bushing <NUM> and the bus <NUM> are inserted into the connector <NUM> in the arrow directions in <FIG>, the insulating plug <NUM> is inserted into the connector <NUM> in an arrow direction in <FIG>, and the first tightening portion <NUM> and the second tightening portion <NUM> are tightened, whereby the bus connection portion <NUM> is assembled.

As described above, the bus <NUM>, the bushing <NUM>, and the insulating plug <NUM> are inserted into the openings <NUM> of the connector <NUM>, whereby the bus connection portion <NUM> is formed. In this case, the openings <NUM> of the connector <NUM> are closed by the bus <NUM>, the insulating plug <NUM>, and the bushing <NUM> that are inserted. In particular, when the insulating plug <NUM> is inserted after the bus <NUM> and the bushing <NUM> are inserted, gas is likely to remain between the insulating plug <NUM> and the connector <NUM>. Gas present near the bus conductor <NUM> can be a cause of discharge during operation of the switching device <NUM>, leading to insulation deterioration. Therefore, it is necessary to sufficiently exhaust the gas in assembling of the bus connection portion <NUM>.

Considering the above, the bus connection portion <NUM> is assembled while gas is exhausted using an exhaust tool <NUM> shown in <FIG> according to embodiment <NUM>. <FIG> is a plan view of the exhaust tool <NUM> and <FIG> is a side view of the exhaust tool <NUM>. The exhaust tool <NUM> has a bar-shaped body portion <NUM>, a tip portion <NUM> provided at an end of the body portion <NUM>, and a base portion <NUM> provided at another end opposite to the tip portion <NUM>. In the tip portion <NUM>, a hole-shaped holding portion <NUM> is provided so as to penetrate in an X-axis direction in <FIG>, and at the end side, a cut-in portion <NUM> is provided adjacently to the holding portion <NUM>. The cut-in portion <NUM> has a width approximately equal to or smaller than a short-side width (a Z-axis-direction width in <FIG>) of the holding portion <NUM>, and is cut in toward a tip end on the side where the tip portion <NUM> is provided in the exhaust tool <NUM>. The cut-in portion <NUM> is formed in a valley-like shape by being cut in toward the inner side of the exhaust tool <NUM>, i.e., toward the positive or negative direction of the X axis in <FIG>, and has a thin portion left at the bottom of the valley part.

<FIG> shows a schematic plan view of the tip portion <NUM> of the exhaust tool <NUM>, in which the tip portion <NUM> shown in <FIG> is enlarged. The tip portion <NUM> has the through-hole-shaped holding portion <NUM>, and the cut-in portion <NUM> which is adjacent to the holding portion <NUM> and is not penetrated. In <FIG>, the cut-in portion <NUM> is cut in along the long-side direction of the body portion <NUM> toward the end of the tip portion <NUM>. By expanding the hole of the holding portion <NUM>, the first tightening portion <NUM> is allowed to pass through the holding portion <NUM>, and by tearing the cut-in portion <NUM>, the holding portion <NUM> can be released from the first tightening portion <NUM>. That is, the penetrated holding portion <NUM> is put so that the first tightening portion <NUM> passes therethrough, thereby restricting movement of the exhaust tool <NUM>, and after an exhaust process, the exhaust tool <NUM> is drawn in a direction away from the first tightening portion <NUM>, so that the cut-in portion <NUM> can be torn by the first tightening portion <NUM>. Thus, displacement of the exhaust tool <NUM> is prevented and a gas passage is ensured, and the exhaust tool <NUM> can be taken out without leaving at least a part of the body portion <NUM> between the connection surfaces of an inner wall <NUM> of the connector <NUM> and an outer wall <NUM> of the insulating plug <NUM>.

Next, specific operation for assembling the bus connection portion <NUM> using the exhaust tool <NUM> described above will be described. First, the holding portion <NUM> is expanded toward the outer side of the exhaust tool <NUM>, the expanded holding portion <NUM> is hooked on the first tightening portion <NUM> of the bushing <NUM> placed in the connector <NUM>, and the body portion <NUM> of the exhaust tool <NUM> is brought into close contact with the inner wall <NUM> of the connector <NUM>.

In a connection process for the connector <NUM> and the insulating plug <NUM>, when the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> are brought into contact with each other, gas surrounded by the connector <NUM> and the insulating plug <NUM> has no way to escape, and therefore remains between the connector <NUM> and the insulating plug <NUM>. This gas is pressurized and compressed by the insulating plug <NUM> being screwed to the first tightening portion <NUM> of the bushing <NUM>. Here, between the inner wall <NUM> of the connector <NUM> and the insulating plug <NUM>, the exhaust tool <NUM> whose movement is restricted by the holding portion <NUM> is interposed and thus a gap is formed. With this gap, a gas passage is ensured and the pressurized gas is exhausted through the gap to the outside of the connector <NUM>. In addition, the holding portion <NUM> holds the first tightening portion <NUM> so that movement of the exhaust tool <NUM> is restricted during assembly of the bus connection portion <NUM>, and thus it is possible to efficiently exhaust the gas without obstructing the gas passage. Accordingly, while remaining of gas between the connector <NUM> and the insulating plug <NUM> is inhibited, connection between the first electric apparatus <NUM> and the second electric apparatus <NUM> can be made.

Further, shortly before connection between the connector <NUM> and the insulating plug <NUM> is completed, or after the completion, the body portion <NUM> of the exhaust tool <NUM> is drawn from the connector <NUM>, whereby force acts on the cut-in portion <NUM> so that the cut-in portion <NUM> can be torn by the first tightening portion <NUM>. By the cut-in portion <NUM> being severed, holding of the first tightening portion <NUM> by the holding portion <NUM> is released and the exhaust tool <NUM> can be pulled out from the first electric apparatus <NUM> without leaving gas therein. Thus, gas surrounded by the connector <NUM> and the insulating plug <NUM> is exhausted to the outside of the connector <NUM>, and connection between the first electric apparatus <NUM> and the second electric apparatus <NUM> is completed while close contact between the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> is kept.

Here, the tip width of the tip portion <NUM> is preferably tapered toward the tip end, as shown in <FIG>. In a case of such a shape, insertion and extraction of the exhaust tool <NUM> are facilitated and a drawing force at the time of detachment is less likely to concentrate locally on the exhaust tool <NUM>. Thus, the exhaust tool <NUM> can be prevented from being partially left inside the connector <NUM> and between the connection surfaces of the connector <NUM> and the insulating plug <NUM>.

<FIG> shows a schematic side view of the tip portion <NUM> of the exhaust tool <NUM>, in which the tip portion <NUM> shown in <FIG> is enlarged. As shown in <FIG>, the thickness of the tip portion <NUM> preferably decreases toward the tip end. The tip portion <NUM> having such a shape provides effects that the exhaust tool <NUM> can be attached even to a narrow part and a drawing force at the time of detaching the exhaust tool <NUM> does not concentrate locally on the exhaust tool <NUM>. A broken line in <FIG> represents the cut-in portion <NUM> seen through a side surface of the exhaust tool <NUM>, and the cut-in portion <NUM> is provided adjacently to the holding portion <NUM> so as to have a thin portion remaining as shown by the broken line.

<FIG> shows examples of a cross-section along line M-M in <FIG>, i.e., the sectional shape of the body portion <NUM>. The sectional shape of the body portion <NUM> may be a rectangular shape with rounded corners as shown in <FIG>, or an oval shape as shown in <FIG>, for example. Here, the oval shape includes a circle and an elliptic shape. Although not shown, the sectional shape may be a polygonal shape with rounded corners. Thus, by forming the sectional shape of the body portion <NUM> as a rounded-corner shape, it becomes possible to exhaust gas without damaging the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM>. In addition, even when the radial-direction dimensions of the connector <NUM> and the insulating plug <NUM> are small, a necessary strength can be ensured against an insertion/extraction force at the time of inserting/extracting the exhaust tool <NUM>.

<FIG> is an enlarged view of a part of the body portion <NUM>. As shown in <FIG>, recesses <NUM> and projections <NUM> may be formed on the body portion <NUM>. For example, the recesses <NUM> and the projections <NUM> may be provided over a range from the body portion <NUM> to the tip portion <NUM> of the exhaust tool <NUM> so as to traverse in the short-side direction. The recesses <NUM> and the projections <NUM> may traverse over a partial range in the short-side direction instead of the entire range. The recesses <NUM> and the projections <NUM> may be provided on only one surface or on a plurality of surfaces. The recesses <NUM> and the projections <NUM> may be arranged in a dotted manner instead of traversing.

By providing the recesses <NUM> and the projections <NUM> as described above, it is possible to perform the exhaust process without hindering flow of an insulating lubricant such as paste or oil applied to the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> at the time of connecting the connector <NUM> and the insulating plug <NUM>.

The exhaust tool <NUM> may be made from a flexible and lubricating material such as fluororesin, for example. The exhaust tool <NUM> may be made from polypropylene resin, polyamide resin, polyether ether ketone resin, or polyacetal resin. The exhaust tool <NUM> may be formed by impregnating a polyamide fiber with polypropylene resin. By using a composite material obtained by impregnating a reinforced fiber such as a polyamide fiber with resin, the strength can be ensured and thus damage and breakage are prevented when the exhaust tool <NUM> is extracted, whereby a part thereof can be prevented from being left between the connection surfaces of the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM>.

For the connector <NUM>, for example, a deformable and restorable material such as silicone resin or ethylene propylene rubber may be used so that the exhaust tool <NUM> can be interposed between the connection surfaces of the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM>.

As described above, the exhaust tool <NUM> having the through-hole-shaped holding portion <NUM> and the cut-in portion <NUM> not penetrated is used in assembly of the bus connection portion <NUM>, whereby movement of the exhaust tool <NUM> is restricted and a gas passage is ensured while gas can be efficiently exhausted. After the gas is sufficiently exhausted, the cut-in portion <NUM> is severed and thus the exhaust tool <NUM> can be extracted. Therefore, the gas in the bus connection portion <NUM> can be assuredly exhausted.

The present embodiment has shown the case where the connector <NUM> has the openings <NUM> in three ways and one of the openings <NUM> is closed by the bushing <NUM>. However, without using the bushing <NUM>, the connector may be configured such that the openings <NUM> are provided in two ways with one opening closed and the first tightening portion <NUM> is provided inside.

<FIG> shows an exhaust tool according to embodiment <NUM>. The same components as in embodiment <NUM> are denoted by the same reference characters and the description thereof is omitted.

In <FIG> is a plan view of an exhaust tool <NUM> and <FIG> is a side view of the exhaust tool <NUM>. The exhaust tool <NUM> according to embodiment <NUM> includes the bar-shaped body portion <NUM> and the tip portion <NUM> provided at the end of the body portion <NUM>. As shown in <FIG> which is an enlarged view of the tip portion <NUM> in <FIG>, the tip portion <NUM> has the hole-shaped holding portion <NUM> through which the first tightening portion <NUM> can pass and which is provided so as to penetrate in the X-axis direction in <FIG>. The periphery of the holding portion <NUM> is surrounded by a support portion <NUM>. Unlike embodiment <NUM>, it is not necessary to expand the hole in the short-side direction of the exhaust tool <NUM> so as to allow the first tightening portion <NUM> to pass therethrough.

<FIG> shows a schematic plan view of the tip portion <NUM> of the exhaust tool <NUM>, in which the tip portion <NUM> shown in <FIG> is enlarged. As shown in <FIG>, the cut-in portion <NUM> is provided between the body portion <NUM> and the support portion <NUM>. The cut-in portion <NUM> is provided at the outer edge of the support portion <NUM> adjacently to the holding portion <NUM>, and is cut in along the short-side direction of the body portion <NUM>. When the body portion <NUM> and the support portion <NUM> are pulled in directions opposite to each other, the cut-in portion <NUM> not penetrated is torn and thus the body portion <NUM> and the support portion <NUM> can be separated with the cut-in portion <NUM> as a boundary.

<FIG> shows a schematic side view of the tip portion <NUM> of the exhaust tool <NUM>, in which the tip portion <NUM> shown in <FIG> is enlarged. The tip portion <NUM> is formed such that the thickness thereof decreases toward the tip end, and the end of the tip portion <NUM> is thinnest.

In a case of assembling the bus connection portion <NUM> using the exhaust tool <NUM>, a lubricant is applied in advance to the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> which are the connection surfaces of the first electric apparatus <NUM> and the second electric apparatus <NUM>. Thereafter, the holding portion <NUM> of the exhaust tool <NUM> is hooked on the first tightening portion <NUM> in the first electric apparatus <NUM>, and the body portion <NUM> of the exhaust tool <NUM> is brought into close contact with the inner wall <NUM> of the first electric apparatus <NUM>, thus making preparation before assembly.

Then, as in embodiment <NUM>, the first electric apparatus <NUM> and the second electric apparatus <NUM> are assembled while positional displacement of the exhaust tool <NUM> is prevented by the holding portion <NUM>. Shortly before completion of the assembly, or after the completion, the base portion <NUM> is pulled so as to draw the exhaust tool <NUM> from the connector <NUM>, whereby the cut-in portion <NUM> provided between the body portion <NUM> and the support portion <NUM> of the exhaust tool <NUM> is torn and the body portion <NUM> and the support portion <NUM> are separated. Thus, the body portion <NUM> can be extracted to the outside of the connector <NUM>. Although the support portion <NUM> is left between the first electric apparatus <NUM> and the second electric apparatus <NUM>, the surrounding space around the support portion <NUM> is at the same potential and therefore there is no electrical problem.

The through-hole-shaped holding portion <NUM> and the support portion <NUM> supporting the holding portion <NUM> may be formed in various shapes such as a circle, a quadrangle with rounded corners, a triangle with rounded corners, and a rhombus with rounded corners as shown in <FIG>. Thus, the shape of the support portion <NUM> may be changed so as to be appropriate for insertion and extraction of the exhaust tool <NUM>.

For example, if the support portion <NUM> has a polygonal shape, a frictional force acting on corners of the support portion <NUM> becomes smaller than in a case of having a shape with no corners, and thus the polygonal shape is more appropriate for insertion and extraction of the exhaust tool <NUM>. If the support portion <NUM> has a rounded-corner shape or an elliptic shape including a circle, damage of the connector <NUM> and the insulating plug <NUM> can be prevented at the time of inserting/extracting the exhaust tool <NUM>.

As described above, the exhaust tool <NUM> having the through-hole-shaped holding portion <NUM>, the cut-in portion <NUM> not penetrated, and the support portion <NUM> is used in assembly of the bus connection portion <NUM>, whereby movement of the exhaust tool <NUM> is restricted and a gas passage is ensured while gas can be efficiently exhausted. After the gas is sufficiently exhausted, the cut-in portion <NUM> is severed to separate the body portion <NUM> and the support portion <NUM>, and thus the body portion <NUM> can be easily extracted. Therefore, the gas in the bus connection portion <NUM> can be assuredly exhausted.

Embodiment <NUM> has shown the case where the sectional shape of the body portion <NUM> is a rectangular shape with rounded corners or an oval shape. However, sectional shapes shown in <FIG> may be employed. Each sectional shape in <FIG> corresponds to the sectional shape along line M-M in <FIG> or <FIG>. In <FIG>, sectional shapes of the body portion <NUM> are shown in cells arranged in columns and rows. The features of the columns are as follows: in column <NUM>, the outer shape is a quadrangular shape with rounded corners; in column <NUM>, the outer shape is an oblong shape; in column <NUM>, the outer shape is an elliptic shape; and in column <NUM>, the outer shape is a rhombus. The features of the rows are as follows: in row A, there are no grooves on the surface; in row B, the upper and lower surfaces have grooves extending from the base portion <NUM> to the tip portion <NUM>; in row C, one surface has a groove extending from the base portion <NUM> to the tip portion <NUM>; and in row D, both side surfaces of the body portion <NUM> have grooves extending from the base portion <NUM> to the tip portion <NUM>.

The sectional shape of the body portion <NUM> can be selected from various shapes as shown in <FIG>. Thus, the sectional shape of the body portion <NUM> may be changed so as to be appropriate for insertion and extraction of the exhaust tool <NUM> or the exhaust tool <NUM>. If the sectional shape of the body portion <NUM> is a polygonal shape, the contact areas where the surface of the body portion <NUM> contacts with the inner wall <NUM> and the outer wall <NUM> are increased as compared to a case where the surface of the body portion <NUM> has a curved shape, and therefore the body portion <NUM> can be prevented from being displaced so as to follow rotation of the insulating plug <NUM>. If the sectional shape of the body portion <NUM> is a rounded-corner shape or an oval shape, damage of the connector <NUM> and the insulating plug <NUM> can be prevented at the time of inserting/extracting the exhaust tool <NUM> or the exhaust tool <NUM>. If the body portion <NUM> has a groove extending from the tip portion <NUM> to the base portion <NUM> as shown in rows B, C, D in <FIG>, a gap formed between the connection surfaces of the connector <NUM> and the insulating plug <NUM> when the exhaust tool <NUM> or the exhaust tool <NUM> is interposed, is enlarged. Thus, the gas remaining between the connector <NUM> and the insulating plug <NUM> can be sufficiently exhausted.

With reference to <FIG>, the exhaust process using the exhaust tool <NUM> according to embodiment <NUM> in manufacturing of the switching device <NUM> will be described. The bus connection portion <NUM> of the switching device <NUM> shown in <FIG> includes at least parts of the first electric apparatus <NUM> and the second electric apparatus <NUM> as shown in <FIG>, the first electric apparatus <NUM> is composed of the bushing <NUM>, the bus <NUM>, and the connector <NUM>, and the second electric apparatus <NUM> is composed of the insulating plug <NUM> and the ground apparatus (not shown) connected to the insulating plug <NUM>.

The first electric apparatus <NUM> is formed by inserting the bus <NUM> and the bushing <NUM> into the openings <NUM> of the connector <NUM>. The bushing <NUM> is inserted into the opening <NUM> of the connector <NUM> so that one opening <NUM> is closed. After the bushing <NUM> is inserted, the bus <NUM> is inserted into another opening <NUM> of the connector <NUM> so that the opening <NUM> is closed. The bushing <NUM> includes the first tightening portion <NUM>, the divided terminal <NUM>, and the conductive member <NUM>. The bus <NUM> is formed by the bus conductor <NUM> and the insulation shield <NUM> surrounding the periphery thereof, and the bus conductor <NUM> is exposed at the end of the bus <NUM>. When the bus conductor <NUM> is inserted, the end of the inserted bus <NUM> is held from the upper and lower sides by the divided terminals <NUM> of the bushing <NUM>, and the side part of the end of the bus <NUM> is supported by the conductive member <NUM>. By contact with the divided terminals <NUM> and the conductive member <NUM>, the bus <NUM> and the bushing <NUM> are electrically connected, so that another electric apparatus provided to the switching device <NUM> and connected to the bushing <NUM>, and the first electric apparatus <NUM>, are electrically connected. Since the openings <NUM> into which the bushing <NUM> and the bus <NUM> are inserted are closed, the gas passages are closed.

In the first electric apparatus <NUM>, after the above connection process, the first tightening portion <NUM> provided in the bushing <NUM> protrudes inside the connector <NUM> toward the opening <NUM> of the connector <NUM> which is not closed by the bus <NUM> and the bushing <NUM>. The first tightening portion <NUM> is, for example, a stud bolt having external threads on both sides, and the first tightening portion <NUM> and a tightening portion of another electric apparatus are fitted to each other, whereby the first electric apparatus <NUM> and the other electric apparatus are connected. In the present embodiment, the tightening portion of the other electric apparatus is the second tightening portion <NUM>, and the other electric apparatus is the second electric apparatus <NUM>. The second tightening portion <NUM> provided inside the insulating plug <NUM> and the first tightening portion <NUM> are fitted to each other, whereby the first electric apparatus <NUM> and the second electric apparatus <NUM> are connected.

Next, with reference to <FIG>, an exhaust procedure in the connection process for the first electric apparatus <NUM> and the second electric apparatus <NUM> will be described. In advance, an insulating lubricant is applied to the connection surfaces of the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> which are the connection surfaces of the first electric apparatus <NUM> and the second electric apparatus <NUM>. For example, grease is used as the lubricant.

Then, as shown in <FIG>, the exhaust tool <NUM> is placed in the opening <NUM> along the inner wall <NUM> of the connector <NUM>, and the holding portion <NUM> of the exhaust tool <NUM> is put so that the first tightening portion <NUM> passes therethrough. Thus, the exhaust tool <NUM> is mounted in the opening <NUM>. In a case where the exhaust tool <NUM> having the holding portion <NUM> in a closed state is used, the holding portion <NUM> is pulled outward of the exhaust tool <NUM> to expand the through hole so that the first tightening portion <NUM> can be inserted into the holding portion <NUM>.

After the exhaust tool <NUM> is mounted in the opening <NUM>, the inner wall <NUM> of the connector <NUM> provided to the first electric apparatus <NUM> and the outer wall <NUM> of the insulating plug <NUM> provided to the second electric apparatus <NUM> are fitted to each other, so that the exhaust tool <NUM> is interposed between their connection surfaces. Here, the inner wall <NUM> and the outer wall <NUM> have such dimensions as to closely contact with each other when fitted.

Inside the insulating plug <NUM>, the second tightening portion <NUM> having an internal thread on the inner side is provided at one end in the direction of a driving shaft <NUM>. In addition, a rotation member <NUM> for rotating the insulating plug <NUM> is provided at the other end in the direction of the driving shaft <NUM>. Here, the rotation member <NUM> has, for example, a hexagonal portion <NUM> for rotation, at an end thereof. By rotating the insulating plug <NUM> using a torque wrench <NUM> having the driving shaft <NUM> and a socket <NUM>, the first electric apparatus <NUM> and the second electric apparatus <NUM> are connected.

Inside the first electric apparatus <NUM>, the divided terminal <NUM> connected to the bus <NUM> of the switching device <NUM> is provided. At an end of the divided terminal <NUM>, the first tightening portion <NUM> having an external thread on the outer circumference thereof is provided so as to protrude toward the second electric apparatus <NUM>. With the insulating plug <NUM> inserted into the connector <NUM>, when the insulating plug <NUM> is rotated in a direction A in <FIG> (clockwise direction as seen from the upper side of the torque wrench <NUM>), the insulating plug <NUM> is driven in a direction to be inserted into the connector <NUM>, so that the first tightening portion <NUM> and the second tightening portion <NUM> are tightened.

Through the process of inserting the insulating plug <NUM>, the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> come close to each other and then closely contact with each other. Since the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> closely contact with each other, gas present at the close-contact part is surrounded by the connector <NUM> and the insulating plug <NUM> and thus has no way to escape.

After the above process, the insulating plug <NUM> is further rotated by the torque wrench <NUM> so as to be screwed into the connector <NUM>, whereby the gas remaining between the connector <NUM> and the insulating plug <NUM> is compressed. As the insulating plug <NUM> is rotated by the torque wrench <NUM>, the compressed gas moves in the circumferential direction of the outer wall <NUM> of the insulating plug <NUM>, so as to gather in the gap formed by the exhaust tool <NUM> interposed between the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM>. The gas gathering in the gap is exhausted through the gap to the outside.

Then, shortly before connection of the first electric apparatus <NUM> and the second electric apparatus <NUM> is completed, or after the completion, the exhaust tool <NUM> is drawn in a direction to be extracted from the connector <NUM>, i.e., a direction B in <FIG>. By the drawing force, the cut-in portion <NUM> of the exhaust tool <NUM> is torn, so that the body portion <NUM> can be extracted. Then, after the cut-in portion <NUM> is severed, the body portion <NUM> is extracted from the connector <NUM>, and thus connection between the first electric apparatus <NUM> and the second electric apparatus <NUM> is completed while close contact between the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM> is kept.

That is, the exhaust tool <NUM> is placed along the inner wall <NUM> of the connector <NUM>, and the through-hole-shaped holding portion <NUM> is put so that the first tightening portion <NUM> inside the connector <NUM> passes therethrough. Then, the first tightening portion <NUM> and the second tightening portion <NUM> are fitted to each other and the insulating plug <NUM> is rotated with the body portion <NUM> interposed between the inner wall <NUM> of the connector <NUM> and the outer wall <NUM> of the insulating plug <NUM>, so that gas between the connector <NUM> and the insulating plug <NUM> is exhausted through a gap formed by the body portion <NUM> interposed between the insulating plug <NUM> and the connector <NUM>, and the first tightening portion <NUM> and the second tightening portion <NUM> are tightened. Then, while the exhaust tool <NUM> is drawn from the connector <NUM>, the cut-in portion <NUM> is severed and the body portion <NUM> is extracted from the connector <NUM>. Thus, it is possible to efficiently exhaust gas while assembling the bus connection portion <NUM> provided to the switching device <NUM>.

The present embodiment has shown the case of using the exhaust tool <NUM> according to embodiment <NUM>. However, the same effects can be obtained even in a case of using the exhaust tool <NUM> described in embodiment <NUM> to perform the exhaust process in manufacturing of the switching device <NUM>. In this case, in the process of drawing the exhaust tool <NUM>, the support portion <NUM> and the body portion <NUM> are separated and the support portion <NUM> is left in the connector <NUM>.

Embodiments <NUM> to <NUM> have shown the case of connecting the first electric apparatus <NUM> and the second electric apparatus <NUM>, but may be applied to another electric apparatus in the switching device <NUM> or an external electric apparatus connected to the switching device <NUM>.

Claim 1:
An exhaust tool (<NUM>) comprising:
a bar-shaped body portion (<NUM>); and
a tip portion (<NUM>) provided at an end of the body portion (<NUM>),
characterized in that the exhaust tool (<NUM>) further comprises:
a through-hole-shaped holding portion (<NUM>) which is provided at the tip portion (<NUM>) and is configured to restrict movement of the body portion (<NUM>) by being configured to be put so that a first tightening portion (<NUM>) placed inside an insulating connector (<NUM>) of a first electric apparatus (<NUM>) having a bus (<NUM>) and the connector (<NUM>) passes through the holding portion (<NUM>); and
a cut-in portion (<NUM>) which is not configured to be penetrated and is cut in adjacently to the holding portion (<NUM>), the cut-in portion (<NUM>) being formed in a valley-like shape by being cut in toward the inner side of the exhaust tool (<NUM>), the cut-in portion (<NUM>) having a thin portion left at the bottom of the valley part, wherein the cut-in portion (<NUM>) is configured to be torn by the first tightening portion (<NUM>) when the exhaust tool (<NUM>) is drawn in a direction away from the first tightening portion (<NUM>).