JP3092372B2 - Vacuum interrupter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum interrupter provided with a metal bellows protective shield.

[0002]

2. Description of the Related Art A vacuum interrupter is very important together with its driving device as a main component of a vacuum circuit breaker.

[0003] The schematic structure of such a vacuum interrupter is shown in FIG.
Shown in the figure. That is, the electrodes 13 and 14 are integrally provided on the opposing inner end faces of the pair of lead rods 11 and 12 which are linear with each other. One lead rod 11 is integrally fixed to the metal end plate 16 in a state of penetrating the metal end plate joined to one end of the insulating cylinder 15. The other lead rod 12 connected to a driving device (not shown) is
The metal bellows 18 is attached to the metal end plate 17 joined to the other end of the
Through the electrodes 13 and 13 with the operation of the driving device.
The electrode 14 can come into contact with the fixed-side electrode 13 so as to be able to reciprocate in the direction opposite to the electrode 14.

On the other hand, in a vacuum chamber 19 formed in the insulating cylinder 15 and held in a vacuum, a shield 20 having one end fixed to an end plate 16 and surrounding the electrodes 13 and 14 is incorporated. The electrode 1
The vapors of the metals constituting the layers 3 and 14 are prevented from adhering to the inner wall of the insulating tube 15 and causing insulation failure. Similarly, since the thin metal bellows 18 may be damaged by an arc generated when the electrodes 13 and 14 approach each other, a portion of the other lead rod 12 located between the electrode 14 and the metal bellows 18 may be damaged. There is also known one in which a bellows protective shield 21 surrounding a metal bellows 18 is fixed.

FIGS. 5 and 6 show an extracted enlarged cross-sectional shape of a conventional joint portion between the lead rod 12 and the bellows protective shield 21 in such a vacuum interrupter.

In the structure shown in FIG. 5, a large-diameter portion 22 is formed in the middle of the lead rod 12, and the metal bellows 18 and the bellows protective shield 21 are sandwiched between the large-diameter portion 22 via a brazing material (not shown). And is fixed to the lead rod 12. 6 has a cylindrical holder 23 having a large-diameter portion 22 formed on the outer peripheral surface thereof.
By inserting into the holder fitting portion 24 formed in the middle of 2 and forming the caulking portion 25 on a part of the lead rod 12,
After fixing the holder 23 to the lead rod 12, the holder 2
3, the metal bellows 18 and the bellows protective shield 21 are fixed to the lead rod 12 via a brazing material (not shown).

[0007]

In a vacuum interrupter having a conventional structure as shown in FIGS. 5 and 6, the lead rod 12 is inserted into the metal bellows 18 from above and brazed. The large-diameter portion 22 of the lead rod 12 or the holder 23 is merely pressed against the upper end of the metal bellows 18 in a state where the dead weight of the lead rod 12 and the spring force of the metal bellows 18 are balanced. Due to vibration or the like accompanying the handling operation, the contact state may deviate from the normal state, and a minute gap may be generated to cause a vacuum failure.

Further, the spring constant of the metal bellows 18 is temporarily reduced by the heating operation accompanying the brazing operation, and the metal bellows 18 is in a state of being contracted.
It is difficult to secure an appropriate contact pressure between the large diameter portion 22 of the lead rod 12 or the holder 23 and the metal bellows 18 due to a defective setting of an assembly jig (not shown) capable of holding the metal jig 2. There is a possibility that a large gap may be generated between them to cause a vacuum failure.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vacuum interrupter capable of preventing a joint failure between a metal bellows and a lead rod during brazing.

[0010]

A vacuum interrupter according to the present invention hermetically joins one end of a substantially cylindrical metal bellows to a vacuum chamber side of a metal end plate constituting a part of a vacuum vessel, and further comprises a metal bellows. The other end is hermetically bonded to a lead rod having an electrode at an inner end, and the base end of a substantially cylindrical bellows protective shield surrounding at least the other end of the metal bellows is located in the vacuum chamber. In the vacuum interrupter joined to the outer periphery of the fitting shaft, the other end of the metal bellows and the base end of the bellows protective shield are fitted to the lead rod, and one end of the fitting shaft is formed at one end of the fitting shaft. Forming a locking step where the other end of the metal bellows locks,
Further, a caulking portion is formed at the other end of the fitting shaft portion so as to hold the other end of the metal bellows and the base end of the bellows protection shield in an overlapping state.

[0011]

The other end of the metal bellows and the base end of the bellows protective shield are fitted to a fitting shaft formed on a lead rod, and the other end of the metal bellows is fitted to one end of the fitting shaft. It comes into contact with the formed locking step. Then, the other end of the metal bellows and the base end of the bellows protection shield are overlapped with each other, and the other end of the fitting shaft is swaged, and the metal bellows and the bellows protection shield are rattled against the lead rod. And fix them together.

In this state, the other end of the metal bellows and the base end of the bellows protective shield are hermetically joined to the fitting shaft of the lead rod via the brazing material.

[0013]

FIG. 1 is a sectional view of a main part of an embodiment of a vacuum interrupter according to the present invention. That is, an outer peripheral end of a metal end plate 17 having an annular bellows joint 26 formed thereon is brazed to one end of the insulating cylinder 15 made of alumina ceramics, and the bellows joint 26 of the metal end plate 17 is brazed.
One end of an austenitic stainless steel bellows 18 having one end joined to the movable lead rod 12 is brazed.

In the middle of the lead rod 12, there is formed a fitting shaft portion 27 in which the other end of the bellows 18 and the base end of the bellows protective shield 21 located on the vacuum chamber 19 side are fitted. At one end of the shaft portion 27, a locking step 28 to which the other end of the bellows 18 can be locked is formed. A caulking portion 29 is formed at the other end of the fitting shaft 27 so as to hold the other end of the bellows 18 and the base end of the bellows protective shield 21 in an overlapping state.
The other end of the bellows 18 and the base end of the bellows protective shield 21 are fixed integrally with the lead rod 12 in a state where the other end of the bellows 18 and the base end of the bellows protective shield 21 are clamped. A brazing material (not shown) is interposed between the rod 12, the bellows 18, and the bellows protective shield 21, and these are joined in an airtight state.

That is, the other end of the bellows 18 is inserted from above the lead rod 12 into the lead rod 12 in a state where the caulking portion 29 is not formed, and the base end of the bellows protective shield 21 is further connected to the lead rod 12. Although they are inserted from above and placed on the locking step 28 of the lead rod 12, a ring-shaped brazing material may be attached to the fitting shaft 27 of the lead rod 12 simultaneously with these operations. Thus, the other end of the bellows 18 and the bellows protection shield 21
The other end of the fitting shaft portion 27 is swaged in this state, and the other end of the bellows 18 and the bellows protection shield are formed by the swaging portion 29 and the locking step portion 28 formed thereby. 21 is integrally clamped and held with the base end portion.

Next, the lead rod 12 and the bellows 1
8 and the base end of the bellows protective shield 21. Since these are already mechanically integrated, the bellows 18 with respect to the lead rod 12 are vibrated by handling operation or the like. There is no problem that the position of the other end or the base end of the bellows protective shield 21 shifts, and these can be securely hermetically joined.

The other end of the bellows protective shield 21 may have a shape other than that shown in FIG. 1, for example, as shown in FIGS. 2 and 3, without any problem. The members having the same functions as those of the embodiment shown in FIG. 1 described above are denoted by the same reference numerals.

[0018]

According to the vacuum interrupter of the present invention, a fitting shaft is formed on the lead rod so that the other end of the metal bellows and the base end of the bellows protective shield are fitted. Since the other end of the metal bellows and the base end of the bellows protective shield are overlapped and held by the locking step portion and the caulking portion formed in the above, the lead rod is held before the brazing operation. As a result of mechanically fixing the other end of the metal bellows and the base end of the bellows protective shield, there is no problem that their relative positions are shifted, and the airtight joining can be reliably performed.

Further, since the metal bellows is fixed to the lead rod, they can be securely hermetically joined without being affected by a change in the spring constant of the metal bellows during brazing. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a main part in an embodiment of a vacuum interrupter according to the present invention.

FIG. 2 is a sectional view illustrating a structure of a main part in another embodiment of the vacuum interrupter according to the present invention.

FIG. 3 is a sectional view showing a structure of a main part in another embodiment of the vacuum interrupter according to the present invention;

FIG. 4 is a cross-sectional view illustrating a schematic structure of a vacuum interrupter that is an object of the present invention.

FIG. 5 is an extracted enlarged cross-sectional view showing a conventional example of a joint portion between the lead rod and a metal bellows and a bellows protective shield.

FIG. 6 is an enlarged cross-sectional view showing another example of a conventional joint portion of a lead bar and a metal bellows and a bellows protective shield, similarly to FIG.

[Explanation of symbols]

12 is a lead rod, 15 is an insulating cylinder, 17 is a metal end plate, 18
Is a bellows, 19 is a vacuum chamber, 27 is a fitting shaft portion, 28 is a locking step portion, and 29 is a caulking portion.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-96367 (JP, A) JP-A-59-58726 (JP, A) JP-A-59-214122 (JP, A) JP-A-3-3 59921 (JP, A) Japanese Utility Model Showa 55-42228 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 33/66

Claims (1)

(57) [Claims] 1. A substantially cylindrical metal bellows is air-tightly joined to one end of a metal end plate constituting a part of a vacuum vessel on a vacuum chamber side, and the other end of the metal bellows is provided with an electrode at an inner end. A vacuum interrupter in which the base end of a substantially cylindrical bellows protective shield surrounding at least the other end of the metal bellows is joined to the outer periphery of the lead rod located in the vacuum chamber. A rod is formed with a fitting shaft in which the other end of the metal bellows and the base end of the bellows protection shield are fitted, and the other end of the metal bellows is locked to one end of the fitting shaft. Forming a locking step, and further forming a caulking portion at the other end of the fitting shaft portion capable of holding the other end of the metal bellows and the base end of the bellows protective shield in an overlapping state. Characteristic vacuum interrupter .