JP3590472B2 - Vacuum circuit breaker - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vacuum circuit breaker, and in particular, extends the fatigue life of a bellows by adjusting the relationship between the phase of the natural oscillation period of the bellows and the phase of the acceleration of the driving force received by the bellows from the driving device. The present invention relates to a vacuum circuit breaker provided with the intended bellows.
[0002]
[Prior art]
FIG. 9 shows a conventional vacuum valve 1. A fixed electrode side end plate 3 and a movable electrode side end plate 4 are hermetically attached to both ends of a cylindrical insulating container 2 to form a vacuum container. An electrode rod 6 having a fixed electrode 5 at its tip penetrates and is hermetically attached to the fixed electrode side end plate 3, while a bellows 7 is hermetically attached to the center of the movable electrode side end plate 4 and is movable at its tip. The movable electrode rod 9 having the electrode 8 is inserted through the inside of the bellows 7 and airtightly connected to the other side of the bellows 7. In such a vacuum valve 1, the internal vacuum is maintained by the above configuration.
Since the vacuum valve 1 repeatedly turns on and off a large current by opening and closing the fixed electrode 4 and the movable electrode 8, the components of the fixed electrode 5 and the movable electrode 8 are changed by the arc or the like generated when the current is interrupted. The arc shield 10 is provided so as not to adhere to the inner wall of the.
[0003]
The movable electrode rod 9 of the vacuum valve 1 is connected to a drive device 11 which is a mechanical operation device using a cam, a spring, and the like.
In such a vacuum valve 1, the driving device 11 drives the movable electrode rod 9 to move the movable electrode 8 from the open position where the movable electrode 8 is separated from the fixed electrode 5 so as to supply a current. A closing operation in which the electrode 8 moves to a closed position in which the electrode 8 contacts the fixed electrode 5, and an opening operation in which the movable electrode 8 moves from the closed position to the open position in order to cut off a current flowing between the fixed electrode 5 and the movable electrode 8. By performing the opening and closing operation including the separating operation, the device can be used as a device for intermittently flowing current.
[0004]
[Problems to be solved by the invention]
However, the vacuum valve 1 needs to open and close the fixed electrode 5 and the movable electrode 8 at a high speed in order to turn on / off the current. In addition, as shown in FIG. 10, when the opening and closing operation of the driving device 11 is started at the first time point and when the opening and closing operation is completed at the second time point, the driving device 11 drives the movable electrode rod 9 to the bellows 7. The acceleration of force is transmitted. For this reason, when the vacuum valve 1 is driven at a high speed, a transient vibration occurs near the center of the bellows 7, and a stress peak higher than a static stress remaining after the transient vibration damping occurs. Therefore, in general, the fatigue life of the bellows is shorter at high speed operation than at constant speed operation.
Generally, as shown in FIG. 10, the phase at which the acceleration A of the natural vibration of the bellows 7 occurs at the start of the opening / closing operation as the first point in time, and the bellows 7, which is the first acceleration for vibrating the bellows 7, is driven. It is inevitable that the phase of the acceleration A ′ of the driving force received from the device 11 becomes the same. However, even at the completion of the opening / closing operation as the second time point, the driving device 11 stops the movement of the movable electrode rod 9 in the opposite direction to the phase of the natural vibration acceleration A and the first acceleration. When the phase of the driving force acceleration A 'is the same as the second acceleration, the transient amplitude generated near the center of the bellows 7 is amplified, and the fatigue life of the bellows 7 is significantly reduced. When the driving speed of the movable electrode rod 9 is different between the opening operation and the closing operation, the phase at which the acceleration A of the natural vibration of the bellows 7 occurs when the opening and closing operation is completed, and the bellows 7 are driven by the driving device 11. Since the probability that the phase of the acceleration A ′ of the driving force received from the motor becomes the same as the phase becomes higher, there is a problem that the fatigue life of the bellows 7 is more significantly reduced.
Furthermore, when the driving device 11 includes an impact mitigation device for alleviating the impact when the opening and closing operation of the fixed electrode 5 and the movable electrode 8 is completed, the displacement L of the movable electrode rod 9 and the acceleration A ′ of the driving force are reduced. As shown in FIG. 11, the time change characteristic is such that the amount of change of the displacement L before the operation is stopped becomes gentle around the inflection point. In the vacuum valve 1 driven by such a driving device 11, the acceleration of the driving force is generated not only at the time of completion of the opening / closing operation but also at the inflection point. When the phase of the driving force and the phase of the acceleration of the driving force become the same, there is a problem that the reduction in the fatigue life of the bellows becomes more remarkable.
[0005]
In general, a decrease in the fatigue life of a bellows causes vacuum breakage of a vacuum valve through fatigue failure of the bellows, and thus may cause a fatal problem of loss of function as a vacuum valve.
In addition, as a method of improving the fatigue life of the bellows in order to solve such a problem, bellows due to transient vibration and the like are increased due to an increase in the bellows itself due to an increase in the number of bellows, dimensions in the axial and radial directions, and the like. There is a method of relatively reducing the stress received and giving a margin to the fatigue life, but there is a problem that increasing the size of the bellows increases the size of the vacuum valve, which increases the cost, and furthermore, increasing the size of the bellows However, if the bellows is used under the condition that the phase of the acceleration of the natural vibration of the bellows and the phase of the acceleration of the driving force received from the driving device 11 are the same, the same problem as described above occurs, and There has been a problem that a sufficient effect for improving the life may not be obtained in some cases.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vacuum valve including a bellows which solves the above-described problems, and particularly, to provide an economical and reliable method using a bellows which has a longer fatigue life using existing parts. The object is to provide a highly efficient vacuum circuit breaker.
[0007]
[Means for Solving the Problems]
The vacuum circuit breaker according to claim 1, wherein the vacuum circuit breaker has a cylindrical shape and a pair of movable electrodes which are air-tightly mounted through the vacuum case and at least one of which is a movable electrode movable between a closed position and an open position in the vacuum case. And a bellows provided on the movable electrode to make the movable electrode movable and airtight with respect to the vacuum vessel, and connected to the movable electrode to drive the movable electrode between a closed position and an open position, A first acceleration for vibrating the bellows connected to the movable electrode is given at a first point in time when the opening and closing operation is started at the earliest in the opening and closing operation of the movable electrode. in an operation device for providing a second acceleration in the first acceleration in the opposite direction, at at least one of the separable operation and closing operation of the opening and closing operation, the natural vibration period of the axial direction of the entire bellows T1, First on bellows Time interval T2 and integer N until the second time the acceleration is applied a second acceleration from the first time point to be generated, a relationship that satisfies the N-1/4 <T2 / T1 <N + 1/4.
[0008]
In the vacuum circuit breaker according to the second aspect, the first time point is a start time of the opening / closing operation at which the opening / closing operation of the movable electrode is started.
[0009]
In the vacuum circuit breaker according to the third aspect, the second time point is a time point when the opening / closing operation of the movable electrode is completed.
[0010]
In the vacuum circuit breaker according to the fourth aspect, the operating device includes the shock absorbing device, and the second time point is before the opening and closing operation of the movable electrode is completed.
[0011]
In the vacuum circuit breaker according to the fifth aspect, the bellows includes a plurality of bellows pieces that are airtightly connected to each other and have different numbers of peaks.
[0012]
In the vacuum circuit breaker according to the sixth aspect, the bellows includes a plurality of bellows pieces and a connecting member for connecting the bellows pieces to each other in an airtight manner.
[0013]
In the vacuum circuit breaker according to the present invention, the operating device has different driving speeds during the opening operation and the closing operation of the movable electrode, and changes the distance between the electrodes during the opening operation and at the closing operation. It is provided with an inter-electrode distance adjusting device that is different from that during operation.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
1 and 2 show a vacuum valve 12 and a bellows 13 of a natural vibration cycle adjusting type according to the present invention. The configuration of the vacuum valve 12 other than the bellows 13 is exactly the same as the conventional example.
As shown in detail in FIG. 2, the bellows 13 is formed by connecting a plurality of bellows pieces 14 and 15 each having a different number of peaks with a connection fitting 16 which is a connection tool for airtightly connecting the bellows pieces. Accordingly, the natural vibration period of the bellows 13 can be freely adjusted by changing the combination of the number of peaks of the bellows pieces 14 and 15. In this way, by combining the plurality of bellows pieces 14 and 15 in this manner, the entire length of the bellows 13, the characteristics of static generated stress at the time of constant speed driving, the spring constant, and the like can be adjusted.
[0015]
Here, assuming that the natural oscillation period of the bellows 13 is T1, and the time required for the opening operation and the closing operation is T2, it is generally T1 一般 T2, so that T1, T2 and the integer N are:
T2 = NT1 (1)
If T1 is set so as to satisfy the following equation, the time change characteristics of the displacement L of the movable electrode rod 9, the acceleration A 'of the driving force, the axial displacement X near the center of the bellows 13, and the acceleration A of the bellows 13 are shown in FIG. As shown. At this time, at the end of the contact and separation operations, the acceleration A ′ of the driving force and the acceleration A are in opposite phases, and the acceleration A ′ of the driving force acts in a direction to suppress the vibration of the bellows 13. Therefore, the fatigue life of the bellows 13 can be extended.
Equation (1) is an ideal condition, but it is difficult to always satisfy equation (1). On the other hand, even if the phases of the acceleration A 'and the acceleration A of the driving force do not coincide with each other, if the phases are opposite to each other, the effect similar to the ideal condition can be obtained although it is small.
Here, in order for the acceleration A 'of the driving force and the acceleration A to have the opposite phase, in FIG. 3 showing the condition of the expression (1), it is sufficient that the deviation of T1 is within a quarter cycle before and after. Therefore, T1, T2, and N
N − ／ <T2 / T1 <N + ／ (2)
If T1 is set by combining the bellows pieces 14 and 15 so as to satisfy the condition, the acceleration A 'of the driving force acts in a direction to suppress the vibration of the bellows 13 when the opening and closing operation is completed, and the fatigue life of the bellows 13 can be extended. .
[0016]
In this embodiment, the natural vibration period of the entire bellows can be adjusted by the combination of the existing bellows pieces. Since the stress characteristics, spring constant, etc. can also be adjusted, the overall length of the bellows is not changed from that of the conventional bellows, and therefore the fatigue life is long and reliable without changing the size of the vacuum valve. A vacuum circuit breaker with a high bellows can be provided.
[0017]
In the first embodiment, the bellows 13 is configured using three types of bellows pieces. However, in order to adjust the natural vibration period T1 of the bellows 13, a plurality of bellows pieces having different numbers of peaks are used in the present embodiment. The same effect can be obtained by adjusting the natural vibration period of the entire bellows by using different combinations.
[0018]
Embodiment 2 FIG.
FIG. 4 shows a bellows 21 of a natural vibration cycle adjusting type of a vacuum valve according to another embodiment of the present invention. The configuration of the vacuum valve according to the second embodiment other than the bellows 21 is the same as that of the first embodiment.
As shown in detail in FIG. 4, the bellows 21 is formed by airtightly connecting three identical bellows pieces 22 to a connecting fitting 23 having different masses from each other and a connecting fitting 24 so as not to cause a vacuum leak. In the second embodiment, the natural vibration period of the bellows 21 can be freely adjusted by changing the combination of the masses of the connection fittings 23 and 24 connecting the plurality of bellows pieces 22.
[0019]
In the second embodiment, as in the first embodiment, the natural oscillation period T1 of the bellows 21, the required time T2 of the opening operation and the closing operation, and the integer N satisfy the equation (2) described in the first embodiment. By setting T1 as described above, it is possible to provide a vacuum valve including the bellows 21 having a long fatigue life and a high reliability as in the first embodiment.
[0020]
Further, in the second embodiment, three identical bellows pieces are connected by two connection fittings 23 and 24 having different masses from each other to form the bellows 21. However, in order to adjust the natural vibration period T1 of the bellows 21, a plurality of identical bellows pieces are used. Even when the bellows 21 is configured with a combination of the number of bellows pieces and the mass of the connection fitting different from that of the present embodiment, the same effect as in the above case can be obtained.
[0021]
Embodiment 3 FIG.
FIG. 5 shows another embodiment of the vacuum valve of the present invention. In the third embodiment, the configuration other than the driving device 31 is the same as that of the first embodiment.
Since the driving device 31 of the vacuum valve 30 according to the third embodiment includes an impact mitigation device (not shown) that works at the end of the contact and separation operations, the displacement L of the movable electrode rod 9 of the vacuum valve 30 and the acceleration A ′ of the driving force. 6, the amount of change in the displacement L becomes gentle at the inflection point 32, which is a discontinuous point, before the operation is stopped as shown in FIG. An acceleration A ′ of the driving force applied to the bellows 33 is generated.
[0022]
Here, according to the same principle as in the first embodiment, the natural oscillation period T1 of the bellows 33, the required time T3 from the start of the opening / closing operation to the inflection point 32 in the time displacement of the driving device 31, and the integer N are
N − ／ <T3 / T1 <N + ／ (3)
If the T1 is adjusted by changing the combination of the bellows pieces 35 and 36 that are airtightly connected by the connection fitting 34 so as to satisfy the bellows 33, the phase of the acceleration of the natural vibration of the bellows 33 at the inflection point 32 is adjusted. And the phase of the acceleration of the driving force can be reversed.
Further, in the driving device 31 including the shock absorbing device, the acceleration of the driving force acting on the bellows 33 at the start of the opening / closing operation is generated as in the first embodiment. Accordingly, the natural oscillation period T1 of the bellows 33, the required time T2 of the opening operation and the closing operation, and the integer N satisfy the expression (2) shown in the first embodiment, and at the same time, T1, T3 and N satisfy the expression (3). By adjusting T1 such that the following condition is satisfied, the phase of the acceleration of the natural vibration of the bellows 33 and the phase of the acceleration of the driving force can be reversed at both the inflection point 32 and the completion of the opening / closing operation. Therefore, the fatigue life of the bellows 32 can be extended, and at the same time, the reliability of the vacuum valve 30 can be improved.
[0023]
As described above, in the vacuum valve 30 according to the third embodiment in which the driving device 31 includes the shock absorbing device, similarly to the second embodiment, the mass of the connection fitting that connects a plurality of the same bellows pieces is changed to change the mass of the bellows 33. The same effect can be obtained by adjusting the natural vibration period T1.
[0024]
Embodiment 4 FIG.
FIG. 7 shows another embodiment of the vacuum valve of the present invention. In the fourth embodiment, the configuration of the driving device 40 is the same as that of the first embodiment.
In the driving device of the vacuum valve 41 according to the fourth embodiment, the driving speed of the movable electrode rod 9 is different from V and V ′ at the time of the opening operation and at the time of the closing operation, respectively.
Therefore, in the fourth embodiment, an inter-electrode distance adjusting device (not shown) provided in the driving device 40 so that the required time T2 of the opening operation and the required time T2 of the closing operation are equal as shown in FIG. The distance between the fixed electrode 5 and the movable electrode 9, which is the displacement of the movable electrode 9 during the opening operation and the closing operation, is adjusted between the two operations. Accordingly, the displacement D during the opening operation and the displacements D ′ and V, V ′ during the closing operation are D / V = D ′ / V ′ = T2 (4)
Meet.
The driving device 40 is a mechanical device using a cam and a spring, or an electromagnetic device using a solenoid or the like. When the driving device 40 is a mechanical device, it is necessary to adjust the rotation angle of the cam. Thus, in the case of the electromagnetic type, it is possible to satisfy Expression (4) by controlling the current flowing through the solenoid. The adjustment of the distance between the electrodes is performed smoothly so that the acceleration of the driving force hardly occurs when the distance between the electrodes is sufficiently large. There is no hindrance.
[0025]
Therefore, also in the fourth embodiment, a plurality of bellows pieces 44 and 45 having a different number of peaks are hermetically connected by a connection fitting 43 constituting the bellows 42 of the vacuum valve 41 on the same principle as in the first embodiment. By adjusting the natural vibration period T1, the required time T2 of the opening operation and the closing operation, and the integer N so as to satisfy the expression (1) described in the first embodiment, the natural vibration at the completion of the opening / closing operation is obtained. Since the phase of the acceleration of the bellows 42 and the phase of the acceleration of the driving force received by the bellows 42 are opposite to each other, the fatigue life of the bellows 42 can be prolonged and the reliability of the vacuum valve 41 can be improved.
[0026]
As described above, in the vacuum valve 41 of the fourth embodiment, as in the second embodiment, the natural vibration period T1 of the bellows 42 is adjusted by changing the mass of the connection fitting 43 that air-tightly connects a plurality of identical bellows pieces. The same effect can be obtained even if this is done.
[0027]
【The invention's effect】
The vacuum circuit breaker according to claim 1, wherein the vacuum circuit breaker has a cylindrical shape and a pair of movable electrodes which are air-tightly mounted through the vacuum case and at least one of which is a movable electrode movable between a closed position and an open position in the vacuum case. And a bellows provided on the movable electrode to make the movable electrode movable and airtight with respect to the vacuum vessel, and connected to the movable electrode to drive the movable electrode between a closed position and an open position, A first acceleration for vibrating the bellows connected to the movable electrode is applied at the first point in time at which the opening and closing operation is started at the earliest during the opening and closing operation of the movable electrode. An operating device that applies a second acceleration in a direction opposite to the first acceleration at the time, and in at least one of the opening operation and the closing operation of the opening and closing operation, the axial natural vibration period T1 of the entire bellows. No. on bellows Since the time interval T2 and the integer N from the first time point at which the second acceleration acts to the second time point at which the second acceleration acts have a relationship of N − ／ <T2 / T1 <N + ／, At the completion of the operation, the acceleration of the driving force received by the bellows from the driving device and the acceleration of the natural vibration of the entire bellows are in opposite phases, and the fatigue life of the bellows can be extended by reducing the stress applied to the bellows.
[0028]
In the vacuum circuit breaker according to the fifth aspect, since the bellows are provided with a plurality of bellows pieces that are airtightly connected to each other and have different numbers of peaks, the combination of the bellows pieces is changed to change the combination of the bellows pieces. The natural oscillation period can be adjusted.
[0029]
In the vacuum circuit breaker according to claim 6, the bellows is provided with a plurality of bellows pieces and a connecting member for connecting the bellows pieces to each other in an airtight manner. Can be adjusted.
[0030]
In the vacuum circuit breaker according to the present invention, the operating device has different driving speeds during the opening operation and the closing operation of the movable electrode, and changes the distance between the electrodes during the opening operation and at the closing operation. It is equipped with an inter-electrode distance adjustment device that is different from the operation time.By adjusting the time required for the opening operation and the closing operation, the acceleration of the driving force that the bellows receives from the driving device when the opening and closing operation is completed When the acceleration of the natural vibration of the bellows and the acceleration of the natural vibration of the bellows are in opposite phases, the fatigue life of the bellows can be extended by reducing the stress applied to the bellows.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a vacuum circuit breaker of the present invention.
FIG. 2 is a conceptual diagram showing a bellows of the vacuum circuit breaker of the present invention.
FIG. 3 is a diagram showing a time change characteristic of the operation of the bellows of the vacuum circuit breaker of the present invention.
FIG. 4 is a conceptual diagram showing a bellows of a vacuum circuit breaker according to another embodiment of the present invention.
FIG. 5 is a conceptual diagram showing a bellows of a vacuum circuit breaker according to another embodiment of the present invention.
FIG. 6 is a diagram showing a time change characteristic of the operation of a bellows of a vacuum circuit breaker according to another embodiment of the present invention.
FIG. 7 is a conceptual diagram showing a bellows of a vacuum circuit breaker according to another embodiment of the present invention.
FIG. 8 is a diagram showing a time change characteristic of the operation of a bellows of a vacuum circuit breaker according to another embodiment of the present invention.
FIG. 9 is a conceptual diagram showing a bellows of a conventional vacuum circuit breaker.
FIG. 10 is a diagram showing a time change characteristic of the operation of the bellows of the conventional vacuum circuit breaker.
FIG. 11 is a diagram illustrating a time change characteristic of the operation of a bellows by a driving device including a conventional shock absorber for a vacuum circuit breaker.
[Explanation of symbols]
2 Insulating container, 3 fixed electrode side end plate, 4 movable electrode side end plate, 5 fixed electrode, 6 electrode rod, 8 movable electrode, 9 movable electrode rod, 10 arc shield, 11, 31, 40 drive device, 12, 30 , 41 Vacuum valve, 13, 21, 33, 42 Bellows, 14, 15, 22, 35, 36, 44, 45 Bellows pieces, 16, 23, 24, 34, 43 Connecting fitting, 32 Inflection point.

Claims (7)

A cylindrical vacuum vessel,
A pair of electrodes that are airtightly mounted through the vacuum container and at least one of which is a movable electrode movable between a closed position and an open position in the vacuum container,
A bellows provided on the movable electrode to make the movable electrode movable and airtight with respect to the vacuum vessel;
The movable electrode is connected to the movable electrode to drive the movable electrode between the closed position and the open position, and is connected to the movable electrode at the first time point when the opening and closing operation of the movable electrode is started at the earliest. An operating device that applies a first acceleration for vibrating the bellows and applies a second acceleration in a direction opposite to the first acceleration at a second point in time when the opening and closing operation is completed at the latest during the opening and closing operation of the movable electrode. With
In at least one of the opening operation and the closing operation of the opening / closing operation, the axial natural vibration period T1 of the entire bellows, and the first acceleration from the first point in time at which the first acceleration is generated in the bellows. The time interval T2 and the integer N up to the second time point at which the acceleration of 2 acts are:
N − ／ <T2 / T1 <N + ／
A vacuum circuit breaker that satisfies the relationship. The vacuum circuit breaker according to claim 1, wherein the first time point is a start time of an opening / closing operation at which the opening / closing operation of the movable electrode is started. 3. The vacuum circuit breaker according to claim 1, wherein the second time is a time when the opening and closing operation of the movable electrode is completed. 3. The vacuum circuit breaker according to claim 1, wherein the operating device includes an impact mitigation device, and the second time point is before the opening and closing operation of the movable electrode is completed. The vacuum circuit breaker according to any one of claims 1 to 4, wherein the bellows comprises a plurality of bellows pieces that are airtightly connected to each other and have different numbers of peaks. The vacuum circuit breaker according to any one of claims 1 to 5, wherein the bellows includes a plurality of bellows pieces and a connecting tool for airtightly connecting the bellows pieces to each other. The operating device has different driving speeds for the opening operation and the closing operation of the movable electrode, and makes the distance between the electrodes different between the opening operation and the closing operation. The vacuum circuit breaker according to any one of claims 1 to 6, further comprising an inter-electrode distance adjusting device.

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