JP3929144B2 - Center clamp type bushing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a center clamp type bushing having a soot tube provided with a conductive soot, and particularly relates to a novel conductive structure between a soot tube surface scissor portion and a metal fitting member connected to both ends of the soot tube.
[0002]
[Prior art]
Conventionally, as shown in FIG. 7, the bushing is a fitting member such as an oil chamber 21 at the top, a flange fitting 22 at the middle, and a bottom fitting 23 at the bottom with respect to the combination of the upper and lower pipes 11 and 12. Concatenated. And there are the following two types of connecting structures between the soot tube (11, 12) and the metal fittings (21, 22, 23) depending on the way of connecting.
[0003]
In the case of a normal bushing, a porcelain end flange fitting (not shown) fixed with a bonding material such as Portland cement is provided at both ends of the soot pipes (11, 12). A structure in which the members (21, 22, 23) are connected by bolting is employed.
[0004]
In the case of a system called a center clamp type, as illustrated in FIG. 7, a combination of the upper soot pipe 11, the flange fitting 22, and the lower soot pipe 12 is sandwiched between an oil chamber 21 and a bottom fitting 23, and this oil A structure is adopted in which the chamber 21 and the bottom metal fitting 23 are fastened together by a central conductor 3 penetrating the whole up and down to connect the members.
[0005]
In this case, in order to prevent damage to the porcelain soot tube and to ensure airtightness between the members, for example, the gasket 22a is provided with a predetermined gap between the end of the upper soot tube 11 and the end of the flange fitting 22. Is interposed. Further, a slip-off preventing member 24a such as a press board is fitted between the sleeve 24 provided on the inner peripheral portion of the flange fitting 22 and the inner periphery of the end portion of the soot tube 11, and a vibration such as an earthquake occurs. Even in this case, the positional relationship is regulated so that the shaft core of the soot tube and the metal fitting member does not shift. In addition, although the said gap | interval of a soot pipe and a metal fitting member produces a minute fluctuation | variation by the tightening degree of a center conductor, or the thermal expansion difference of each member, etc., the said gasket has also fulfill | performed the function which absorbs those fluctuation | variations. .
[0006]
As a surface glaze for a porcelain soot tube, there is a case where a conductive glaze, which is a special glaze imparted with weak electrical conductivity, is applied instead of a normal highly insulating glaze. Such a conductive soot can improve the antifouling property or equalize the electric field distribution by applying a predetermined weak current to the surface glaze based on the potential difference between the metal members at both ends insulated by the soot tube. The metal plate member to which a potential is applied needs to be electrically connected to the conductive rod itself because it exhibits the function of the period.
[0007]
Therefore, in the normal type bushing by cementing as described above, when trying to use this pipe with conductive flaws, there is a suitable conductive cement in the cement itself for bonding between the pipe and the metal fitting. The metal member and the conductive rod can be electrically connected. However, in the case of the center clamp type bushing described above, since a gap is provided by a gasket between the soot tube and the metal fitting member, conduction cannot be obtained. For this reason, it has been conventionally considered that a conductive rod cannot be applied to the center clamp type bushing.
[0008]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and in the center clamp type bushing, the reliability is high, provided between the glaze portion on the surface of the soot tube and the metal fittings arranged at both ends of the soot tube. A practical electrical connection structure is proposed, and a center-clamped bushing is provided that allows a porcelain porcelain tube provided with a conductive cage to be applied to a center-clamped bushing.
[0009]
[Means for Solving the Problems]
The above-mentioned problem is a center clamp type bushing having a soot tube with conductive flaws on the surface and a metal fitting member connected to both ends thereof, and is electrically connected to the metal fitting member and has an elasticity. This is solved by a center-clamped bushing having a soot tube with a conductive soot that is in contact with a conductive soot in the vicinity of the soot end and electrically connecting the conductive soot and the bracket member. can do.
[0010]
And this invention can be preferably embodied as a center clamp type bushing of each of the following forms.
(1) A form in which a ring-shaped elastic clamp fitting is fitted to the flange surface in the vicinity of the flange end portion and the clamp fitting and the fitting member are connected by a bond line.
(2) A plurality of elastic contact pieces each having a base portion fixed to the metal fitting member and having a distal end portion extending in the direction of the flange surface in the vicinity of the flange tube end portion are arranged, and the elastic contact pieces are pressed against the flange surface to perform the conductive operation. A form in which the collar and the metal member are electrically connected.
(3) A sleeve capable of enclosing the end of the soot tube is formed on the outer periphery of the metal fitting, and electrically connected via a conductive rubber piece in the gap between the sleeve and the soot surface near the end of the soot tube Form.
(4) A sleeve that can surround the end of the soot tube is formed on the outer periphery of the metal fitting member, and a conductive elastomer that is injected and cured in an elastic state is inserted into the gap between the sleeve and the soot surface near the end of the soot tube. A form in which the connection portion is electrically connected and the connection portion is covered with an insulating elastomer.
(5) In each of the above embodiments, the thickness of the conductive rod in the vicinity of the end portion of the soot tube is made thicker than other portions.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, each embodiment which put the center clamp type bushing of the present invention into practical use will be described with reference to FIGS.
(1) In FIG. 1, as a first embodiment, a center clamp type bushing in which a certain interval is set between the end surface of the tub tube 1 and the end surface 20 of the metal fitting member 2 by interposing a gasket 20a. The main part of the structure is illustrated. Here, as described above, the slip stopper 24a is disposed between the sleeve 24 provided on the metal fitting member 2 side and the inner side of the end portion of the soot tube so as to be located inside the soot tube 1. It is the same.
[0012]
A feature of this embodiment is that a ring-shaped elastic clamp fitting 4 is fitted in the vicinity of the end portion of the soot tube 1 so as to be in close contact with the surface of the conductive rod 13, and the clamp fitting 4 and the fitting member 2 are connected to each other. It is in the point which connected with the bond line 41 which consists of flexible metal wires. By adopting such a structure, the conductive rod 13 provided on the surface of the rod tube 1 can be electrically connected to the metal fitting 2, so in the center clamp type bushing, the conductive rod 13 13, the necessary weak current flows as described above, and the effect inherent to the conductive basket is exhibited. In addition, since the bond wire acts as a buffer material and can absorb the displacement against the minute fluctuation in the interval between the rod tube and the metal member described above, a connection structure suitable for the center clamp type bushing can be obtained. .
[0013]
In this case, the electrical connection structure between the conductive rod 13 and the metal fitting 2 is the oil chamber and the upper metal pipe, the upper metal pipe and the flange metal, the flange metal fitting and the lower metal pipe, and the lower metal pipe and the bottom in the center clamp type bushing. It can be applied between a porcelain insulator tube such as a metal fitting and a metal fitting member. Of course, the same applies to the description of each embodiment described later.
[0014]
In the case of this embodiment, as shown in FIG. 2, the ring-shaped elastic clamp fitting 4 is formed in a ring shape that can substantially surround the rod tube 1, and the surface of the conductive rod 13 is fastened by the entire clamp fitting 4. It can be embodied in a form of close contact.
In addition, as this clamp metal fitting 4, spring steel like stainless steel is suitable, and it is good to make it the state which provided the space 42 in the edge part and was separated like FIG. In addition, a flexible metal wire that is difficult to oxidize can be appropriately used for the bond wire 41, and an appropriate fixing method such as screwing can be used for attaching both ends thereof.
[0015]
In addition, as shown in FIG. 1, the portion of the conductive rod 13 to which the clamp fitting 4 is in close contact can be provided with a fixed mounting position of the clamp fitting 4 by forming a shallow concave groove 13 a along the outer periphery of the rod pipe. Thus, there is an advantage that a secure mounting without loosening is possible.
[0016]
(2) FIG. 3 shows a second embodiment in which a metal elastic contact piece 5 is interposed between the metal fitting 2 and the conductive rod 13. Specifically, in this embodiment, a plurality of elastic contact pieces 5 having a base portion fixed to the metal fitting member 2 and a distal end portion extending in the surface direction of the conductive rod 13 in the vicinity of the end portion of the soot tube 1 are provided along the perimeter of the soot tube. A structure in which the conductive contact 13 and the metal fitting member 2 are electrically connected by pressing the elastic contact pieces 5 onto the surface of the conductive support 13 is adopted.
[0017]
Also in this embodiment, it is possible to provide a connection structure that can absorb minute fluctuations in the gap between the soot tube and the metal fitting member. Further, when the elastic contact piece 5 is pressed against the surface of the conductive rod 13, the elastic contact piece 5 may be pressed by the elastic force of the elastic contact piece 5 itself, but as shown in FIG. If it is set so that the contact piece 5 is pressed and pressed by its elasticity, the reliability of the conductive portion can be further improved.
[0018]
(3) FIG. 4 shows a third embodiment. Specifically, this embodiment specifically has an outer sleeve 25 that can surround the end portion of the soot tube 1 in the outer peripheral portion of the end portion of the metal fitting member 2. And a structure in which a conductive rubber piece 7 is interposed and electrically connected to the gap between the outer sleeve 25 and the surface of the conductive rod 13 in the vicinity of the end of the vertical tube is employed.
In this embodiment, it is possible to absorb minute fluctuations in the gap between the steel tube and the metal member, and since the conductive member used is a soft rubber material compared to the case of the metal of the first and second embodiments, Therefore, there is an advantage that the contact area becomes large and current density concentration and unbalance can be prevented.
[0019]
As the conductive rubber piece 7 in this case, a hard synthetic rubber or the like in which conductive materials such as carbonaceous powder and metal powder are appropriately mixed can be applied, and also has a function of preventing misalignment. Further, the conductive rubber piece 7 may be interposed over the entire circumference of the outer periphery of the soot tube, but a plurality of the conductive rubber pieces 7 may be arranged with a certain interval. Furthermore, it is preferable from the viewpoint of improving durability that the conductive rubber piece 7 is interposed and then covered with a protective insulating elastomer (not shown).
[0020]
(4) FIG. 5 shows a fourth embodiment. As in the case of the third embodiment, an outer sleeve 25 is formed on the outer peripheral portion of the end portion of the metal fitting 2, and this sleeve 25 The conductive elastomer 8 is injected into the gap between the end of the pipe and the vicinity of the conductive rod 13 and cured to an elastic state to be electrically connected, and the connection portion is further covered with an insulating elastomer 81 to provide a protective coating. Adopted.
In this embodiment as well as the third embodiment, it is possible to absorb a minute gap variation between the steel tube and the metal fitting member, and since the conductive elastomer 8 is injected and arranged, the electrical contact becomes more reliable, There is an advantage that current density concentration and imbalance can be effectively prevented.
[0021]
As the conductive elastomer 8, a room temperature curable elastomer, usually a synthetic rubber abbreviated as RTV, is used. As the insulating elastomer 81, silicon RTV can be typically used. By applying the insulating elastomer 81, the deterioration of the conductive elastomer is prevented, the reliability of the conductive portion is improved, and the lifetime is effectively increased. Can be extended.
[0022]
(5) FIG. 6 shows the fifth embodiment, and in each of the embodiments described in (1) to (4), a conductive member that is electrically connected to the metal fitting and has elasticity A specific example of a structure in which the thickness of the conductive rod portion 13b in the vicinity of the end portion of the rod tube 1 corresponding to the rod surface to be formed is made thicker than other portions is shown.
[0023]
The conductive flange portion 13b that is in contact with the conductive member in each of the embodiments is likely to have a non-uniform current density. However, if the thickness is increased, the electrical resistance value per surface area can be reduced, the current density in the vicinity can be relaxed, malfunctions such as abnormal heating can be prevented, and the life of the conductive cage can be extended. Can do. In this case, if the thickness of the conductive rod portion 13b is at least 50% thicker than the other portions, it is sufficient to achieve the above object.
[0024]
Incidentally, the thickness of the conductive rod is originally subjected to fairly strict thickness management as a problem in production management. That is, if the thickness is set large, there is a risk of causing a thermal escape phenomenon, and the variation in thickness is set to a predetermined uniform thickness for the purpose of inhibiting the original purpose of the conductive cage. Production management is performed. However, forming only the thickness of the conductive flange portion 13b in the vicinity of the end portion thicker than other portions is such that the influence on the original purpose is negligible, so strict thickness control is not necessary, and production There are no technical problems.
[0025]
【The invention's effect】
Since the center clamp type bushing of the present invention is configured as described above, in the center clamp type bushing to which a conventional porcelain porcelain tube with conductive flaws could not be applied, it is arranged on the glaze part of the porcelain tube surface and both ends of the porcelain tube. Since a highly reliable and practical electrical connection structure is formed between the metal fitting and the metal fitting, the center clamp type bushing to which a conductive soot tube is applied can be put into practical use for the first time. In addition, according to each embodiment of the present invention, the reliability of the conductive portion can be further improved, and the conductive portion can be prevented from deteriorating and can be effectively extended in life, which can also be used as a slip prevention member. There are excellent effects such as. Therefore, the present invention has an extremely large industrial value as a center clamp type bushing that solves the conventional problems.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing a first embodiment of the present invention.
FIG. 2 is a perspective view showing a clamp fitting of the first embodiment.
FIG. 3 is a cross-sectional view of a main part showing a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a main part showing a third embodiment of the present invention.
FIG. 5 is a cross-sectional view of a main part showing a fourth embodiment of the present invention.
FIG. 6 is a cross-sectional view of a relevant part showing a fifth embodiment of the present invention.
FIG. 7 is a cross-sectional / side view showing a center clamp type bushing.
FIG. 8 is a cross-sectional view of a main part of a center clamp type bushing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Corrugated pipe, 13 Conductive rod, 13a Groove, 2 Bracket member, 20 End face, 20a Gasket, 24 Sleeve, 24a Shift stop member, 25 Outer sleeve, 4 Clamp bracket, 41 Bond wire, 5 Contact piece, 6 Ring spring, 7 conductive rubber pieces, 8 conductive elastomers, 81 insulating elastomers.

Claims (6)

A center-clamp type bushing comprising a metal pipe having a conductive pipe on its surface and a metal member connected to both ends thereof, wherein the conductive member electrically connected to the metal member and having elasticity is connected to the metal pipe end. A center clamp type bushing provided with a hook tube provided with a conductive rod, which is brought into contact with a nearby conductive rod and electrically connected between the conductive rod and the metal fitting member. The center clamp type bushing according to claim 1, wherein a ring-shaped elastic clamp fitting is fitted on the flange surface in the vicinity of the flange end portion, and the clamp fitting and the fitting member are connected by a bond line. A plurality of elastic contact pieces each having a base portion fixed to the metal fitting member and having a distal end portion extending in the direction of the rivet surface near the end of the tub tube are arranged, and the elastic contact pieces are pressed against the heel surface to press the conductive rod and the metal fitting The center clamp type bushing according to claim 1, wherein the member is electrically connected to the center clamp type bushing. A sleeve capable of enclosing the end of the soot tube is formed on an outer peripheral portion of the metal fitting member, and electrically connected via a conductive rubber piece in a gap between the sleeve and the soot surface near the end of the soot tube. The center clamp type bushing according to 1. A sleeve that can surround the end of the soot tube is formed on the outer periphery of the metal fitting member, and a conductive elastomer that is injected and cured in an elastic state is interposed in the gap between this sleeve and the soot surface near the end of the soot tube. The center clamp type bushing according to claim 1, wherein the center clamp type bushing is electrically connected and the connection portion is covered with an insulating elastomer. The center clamp type bushing according to any one of claims 1 to 5, wherein a thickness of the conductive rod in the vicinity of the end portion of the vertical tube is formed thicker than other portions.

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