Patent Grant
10650995
The present invention relates to a vacuum interrupter for use in, for example, a vacuum circuit breaker.
In such a spiral shaped contact 1, when fault current is interrupted, current flows along the contact 1 machined in the spiral shape and thereby generating a magnetic field in a radial direction, and a concentrated arc due to the fault current generated between the contacts 1 is driven in a circumferential direction by the magnetic field, whereby the arc is prevented from remaining in a certain place of the contact 1 and interruption performance is improved. The reinforcement plate 5 prevents metallic vapor or the like generated between the contacts 1 during the interruption of fault current from dispersing to the backside of the contact 1, from attaching to the inner surface of ceramics, and from degrading withstand voltage performance.
Furthermore, generally, contact pressure is exerted between the contacts 1 in a contact closed state; and force exceeding the contact pressure is further temporarily generated at a moment when the contacts 1 collide during contact closing operation, a lot of stress is generated in the contact 1, and the contact 1 is likely to be deformed. The reinforcement plate 5 also combines the role of reinforcing so that the contact 1 does not deform by being arranged on the backside of the contact 1 while coming in contact with the contact 1.
Material such as stainless steel, which is stronger in strength and higher in resistance than the contact 1, is generally used for material of the reinforcement plate 5; however, current is shunted to the reinforcement plate 5 according to the resistance ratio between the contact 1 and the reinforcement plate 5. The spiral shaped groove is not formed in the reinforcement plate 5; and accordingly, a magnetic field is not generated from the current that flows through the reinforcement plate 5, the magnetic field generated from the contact 1 is reduced by the amount of current that flows through the reinforcement plate 5 and it causes to degrade the interruption performance.
For example, if the structure is such that a contact does not come in contact with a reinforcement plate behind the contact as in U.S. Pat. No. 8,039,771, current that flows through the reinforcement plate disappears and a magnetic field generated from the contact increases, but a function serving as the reinforcement of the contact also disappears and the contact is more likely to be deformed.
More particularly, in the case of a contact for use at a high contact pressure and a shape in which a recess at a central portion of the contact is large and which comes in contact at a rim portion as in JP,3812711,B, a problem exists in that deformation of the contact increases and adoption of such a structure is difficult.
Patent Document 1: U.S. Pat. No. 8,039,771
Patent Document 2: JP,3812711,B
In the aforementioned conventional vacuum interrupter, the reinforcement plate is arranged on the back of the contact and comes in contact with the entire surface of the contact in order to reinforce the contact; and accordingly, problems exist in that current during the interruption of fault current flows through not only the contact but also the reinforcement plate, the magnetic field due to the current that flows through the contact is reduced, and the interruption performance is degraded.
The present invention has been made to solve the above described problem, and an object of the present invention is to improve interruption performance and a further object is to provide a vacuum interrupter which can also reinforce a contact.
According to the present invention, there is provided a vacuum interrupter including: a fixed side contact and a movable side contact, each of which is arranged in a vacuum vessel to be able to connect and disconnect, has a contact portion to be connected to and disconnected from each other, and is formed with a plurality of arc shaped grooves from a center portion to a rim portion; a fixed side electrode rod connected to the fixed side contact; a movable side electrode rod connected to the movable side contact; a fixed side reinforcement plate which is arranged between the fixed side electrode rod and the fixed side contact, and whose rim portion has a step portion to be arranged apart from the back of the fixed side contact; and a movable side reinforcement plate which is arranged between the movable side electrode rod and the movable side contact, and whose rim portion has a step portion to be arranged apart from the back of the movable side contact.
Furthermore, according to the present invention, there is provided a vacuum interrupter including: a fixed side contact and a movable side contact, each of which is arranged in a vacuum vessel to be able to connect and disconnect, has a contact portion to be connected to and disconnected from each other, and is formed with a plurality of arc shaped grooves from a center portion to a rim portion; a fixed side electrode rod connected to the fixed side contact; a movable side electrode rod connected to the movable side contact; a fixed side projection portion provided in a central portion on the back side of the fixed side contact; a movable side projection portion provided in a central portion on the back side of the movable side contact; a fixed side reinforcement plate which is arranged between the fixed side electrode rod and the fixed side contact, whose central portion comes in contact with the fixed side projection portion, and whose rim portion has a step portion to be arranged apart from the back of the fixed side contact; and a movable side reinforcement plate which is arranged between the movable side electrode rod and the movable side contact, whose central portion comes in contact with the movable side projection portion, and whose rim portion has a step portion to be arranged apart from the back of the movable side contact.
According to the vacuum interrupter according to the present invention, the reinforcement plate which is arranged between the fixed side electrode rod and the fixed side contact, and whose rim portion has the step portion to be arranged apart from the back of the fixed side contact; and the reinforcement plate which is arranged between the movable side electrode rod and the movable side contact, and whose rim portion has the step portion to be arranged apart from the back of the movable side contact are provided, whereby, each step portion of the reinforcement plate does not come in contact with the fixed side contact and the movable side contact and therefore there can be obtained the vacuum interrupter that can improve interruption performance of the vacuum interrupter while maintaining the strength of a contact portion.
Hereinafter, Embodiment 1 of the present invention will be described based on
In these drawings, a reference numeral 10 denotes a vacuum vessel of the vacuum interrupter and, for example, the vacuum vessel is made of ceramics. 11 denotes a fixed side flange attached to the fixed side of the vacuum vessel 10; 12 denotes a movable side flange attached to the movable side of the vacuum vessel 10; 13 denotes a fixed side electrode rod which is supported to the fixed side flange 11 and is arranged in the vacuum vessel 10; 14 denotes a movable side electrode rod which can pass through the movable side flange 12, is arranged in the vacuum vessel 10, and is coaxially arranged with the fixed side electrode rod 13; and 15 denotes an accordion shaped bellows made of thin metal which is coupled to the movable side electrode rod 14 and the movable side flange 12 and allows the movable side electrode rod 14 to be movable while the interior of the vacuum vessel 10 of the vacuum interrupter is kept vacuum.
16 denotes a fixed side contact which is attached to the tip of the fixed side electrode rod 13 and has a contact portion 16a; and although not shown in the drawing, 17 denotes a movable side contact to be connected to and disconnected from the fixed side contact 16, the movable side contact 17 being attached to the tip of the movable side electrode rod 14 and having a contact portion to be brought into contact with the contact portion 16a. A concave shaped spiral portion 16b is formed in a center portion on the contact portion 16a side of the fixed side contact 16 and arc shaped grooves 16c are formed from the spiral portion 16b toward the rim portion, what is called, a spiral shaped fixed side electrode is constituted.
Furthermore, also in the movable side contact 17, similarly to the fixed side contact 16, a concave shaped spiral portion 17b is formed in a center portion on the contact portion 17a of the movable side contact 17 and arc shaped grooves 17c are formed from the spiral portion 17b toward the rim portion, what is called, a spiral shaped movable side electrode is configured.
18 denotes a spacer arranged between the fixed side electrode rod 13 and the fixed side contact 16; and 19 denotes a reinforcement plate arranged between the spacer 18 and the fixed side contact 16 and a configuration is such that a rim portion of the reinforcement plate 19 has a step portion 19a separated from the back 16d of the fixed side contact 16. More specifically, the configuration is such that the thickness of a central portion of the reinforcement 19 is thickened, the step portion 19a of the reinforcement 19 is thinned than the thickness of the central portion, and the step portion 19a is arranged apart from the back 16d of the fixed side contact 16.
20 denotes a spacer arranged between the movable side electrode rod 14 and the movable side contact 17; 21 denotes a reinforcement plate arranged between the spacer 20 and the movable side contact 17 and a configuration is such that a rim portion of the reinforcement plate 21 has a step portion 21a separated from the back 17d of the movable side contact 17. More specifically, the configuration is such that the thickness of a central portion of the reinforcement 21 is thickened, the step portion 21a of the reinforcement 21 is thinned than the thickness of the central portion, and the step portion 21a is arranged apart from the back 17d of the movable side contact 17.
Incidentally, 22 denotes a shield which is attached inside the vacuum vessel 10 and is arranged over the fixed side contact 16 and the movable side contact 17. Then, the shield 22 prevents metallic vapor, which is diffused from an arc that is ignited between the fixed side contact 16 and the movable side contact 17, from attaching to an inner wall of the vacuum vessel 10.
During energization, the movable side contact 17 is contact closed by an operating mechanism of a circuit breaker (not shown in the drawing) and is pressurized by a contact pressure spring (not shown in the drawing); and when fault current is generated, the movable side contact 17 moves the movable side electrode rod 14 to a contact opened position by the operating mechanism to interrupt large current. After the fixed side contact 16 is separated from the movable side contact 17, the arc is generated between the fixed side contact 16 and the movable side contact 17; however, if the current exceeds approximately 10 kA, the arc is concentrated at one place and becomes a concentrated arc A.
At this time, the spiral shaped groove 16c is formed in the fixed side contact 16 and the spiral shaped groove 17c is formed in the movable side contact 17, the current flows along the shape of the spiral and thereby generating a magnetic field G, and the concentrated arc A is made to rotate and move without being remained at one place by the magnetic field G and arc driving force K by current I, whereby local overheat of the fixed side contact 16 and the movable side contact 17 is suppressed and interruption performance is improved.
For example, although a description will be made on the fixed side contact 16 side, as shown in
For example, as shown in
At this time, the moment M depending on the length of L=(D1−D3)/2 is generated on a contact thin portion L of the fixed side contact 16 in a direction shown in
However, in this Embodiment 1, the diameter D3 of the portion in which the reinforcement 19 comes in contact with the fixed side contact 16 is increased than the inner diameter D1 of the thick portion of the rim portion of the fixed side contact 16, whereby the backside of the thin portion of the fixed side contact 16 can be supported, the moment exerted on the thin portion of the fixed side contact 16 is extremely reduced, and the deformation and/or damage of the fixed side contact 16 can be prevented.
Furthermore, in the spiral shaped contact, the current I flows along the facing spiral shape and thereby generating the magnetic field Gin a radial direction; and as shown in
In the conventional structure shown in
In the vacuum interrupter according to this Embodiment 1, as shown in
As for an inner portion of the diameter D1 of the fixed side contact 16, the fixed side contact 16 comes in contact with the reinforcement plate 19, the current is shunted to the reinforcement plate 19 and the current that flows along the spiral shape is reduced, and the magnetic field is reduced; however, the arc moves to the rim portion by electromagnetic force immediately after arc generation and begins to rotate on the rim portion; and therefore, the influence on the interruption performance is small. More particularly, as for the shape like JP,3812711,B in which the contact portion is positioned in the rim portion, the generation of the arc is limited to the contact portion of the rim portion and thus the influence to be exerted on the interruption performance by a magnetic field at a portion within the diameter D1 is imperceptible.
If the diameter D3 of the portion in which the reinforcement 19 comes in contact with the fixed side contact 16 is increased, an effect as the reinforcement of the fixed side contact 16 increases; however, the magnetic field tends to reduce by an increase in current that flows through the reinforcement plate 19 at the same time and, if the diameter D3 reaches an outer circumferential diameter D2 of the fixed side contact 16, the magnetic field strength becomes the same as that of the conventional structure.
Consequently, the diameter D3 of the portion in which the reinforcement 19 comes in contact with the fixed side contact 16 needs to be smaller than the outer circumferential diameter D2 of the fixed side contact 16. Preferably, a range of D1<D3<(D1+D2)/2 has a profound effect and is effective for an improvement in magnetic field strength. Furthermore, in order not to bring the fixed side contact 16 into contact with the reinforcement plate 19, it is preferable that a level difference is equal to or more than 0.5 mm.
When the large current is interrupted, the metallic vapor generated between the fixed side contact 16 and the movable side contact 17 by the arc is dispersed in the axial direction through the groove 16c of the spiral shaped fixed side contact 16 and is dispersed to the inside or the like of the vacuum vessel 10 made of ceramics in the vacuum interrupter and the withstand voltage performance is degraded; however, the reinforcement plate 19 has the role of blocking the metallic vapor dispersed from the groove 16c of the fixed side contact 16 and preventing the degradation of the withstand voltage performance.
The larger the outer diameter D4 of the reinforcement 19 is, the larger the interruption effect is; however, if the outer diameter D4 is larger than the outer circumferential diameter D2 of the fixed side contact 16, field strength at the tip of the reinforcement plate 19 is increased and the withstand voltage performance is degraded; and thus, it is desirable that the outer diameter D4 is smaller than the outer circumferential diameter D2 of the fixed side contact 16.
The reinforcement plate 19 and the fixed side contact 16 are generally joined by a method such as blazing; however, if temperature in brazing is too high, brazing material between the reinforcement plate 19 and the fixed side contact 16 may creep up near the surface of the contact. However, if the brazing material is present adjacent to the surface of the contact, the brazing material is melted by the arc during the interruption of large current and the interruption performance may be degraded; and thus, control of blazing temperature becomes important.
In the shape of this Embodiment 1, area in which the fixed side contact 16 is blazed to the reinforcement plate 19 is small in the back 16d of the fixed side contact 16, the amount of the brazing material can be reduced, the brazing material can be difficult to creep up adjacent to the surface of the contact even when the brazing temperature is high, the temperature control in brazing becomes easy, and an effect can also be obtained that the vacuum interrupter with higher reliability can be easily manufactured.
In the aforementioned
Embodiment 2 of the present invention will be described based on
In a shape shown in
Embodiment 3 of the present invention will be described based on
In a shape shown in
Incidentally, if the spacer 18 and the fixed side reinforcement plate 24 are made as an integrated structure, the number of components can be further reduced and there can be obtained an effect that can be manufactured more inexpensively.
Embodiment 4 of the present invention will be described based on
The shape of a fixed side reinforcement plate 25 shown in
This allows the fixed side reinforcement plate 25 to be manufactured by press working and a reduction in the number of components and a reduction in cost can be achieved at the same time. Furthermore, effects regarding the improvement in interruption performance and the reinforcement of the fixed side contact 16 in the aforementioned Embodiment 1 can also be similarly obtained.
Embodiment 5 of the present invention will be described based on
In the shape of
The fixed side reinforcement plate 28 has a shape which is plate-shaped, is not provided with a level difference, and is flat washer-shaped. In this Embodiment 5, a level difference is formed by providing the fixed side projection portion 27 in the central portion on the back side of the fixed side contact 16, a portion in which the fixed side projection portion 27 comes in contact with the fixed side reinforcement plate 28 becomes a diameter D3, and effects regarding the improvement in interruption performance and the reinforcement of the fixed side contact 16 in the aforementioned Embodiment 1 can also be similarly obtained.
According to Embodiment 5 of the present invention, the shape of the fixed side reinforcement plate 28 becomes simple and can be manufactured inexpensively by press working or the like. The level difference needs to be formed by providing the fixed side projection portion 27 in the central portion on the back side of the fixed side contact 16; however, since the fixed side contact 16 is generally manufactured by machining from the beginning, an increase in cost by the addition of the level difference is small and there is an advantage that can be manufactured inexpensively as a whole.
Furthermore, a structure in which a spacer 18 is integrated with the fixed side reinforcement plate 28 in this
In the aforementioned Embodiment 2 to Embodiment 5, the fixed side contact 16 side are mainly described; however, although not shown in the drawings, the movable side contact 17 side can be similarly applied and the similar effects can be exhibited.
Incidentally, the present invention can freely combine the respective embodiments and appropriately modify and/or omit the respective embodiments, within the scope of the present invention.
The present invention is suitable for achieving a vacuum interrupter which can improve interruption performance of the vacuum interrupter while maintaining the strength of a contact portion.
10 Vacuum vessel, 13 Fixed side electrode rod, 14 Movable side electrode rod, 16 Fixed side contact, 16a Contact portion, 16c Groove, 16d Back, 17 Movable side contact, 17a Contact portion, 17c Groove, 17d Back, 18 Spacer, 19 Fixed side reinforcement plate, 19a Step portion, 20 Spacer, 21 Movable side reinforcement plate, 21a Step portion, 23 Fixed side reinforcement plate, 23a Step portion, 24 Fixed side reinforcement plate, 24a Step portion, 25 Fixed side reinforcement plate, 25a Step portion, 26a Spacer, 27 Fixed side projection portion, 28 Fixed side reinforcement plate, 28a Step portion
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-083334 | Apr 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/008423 | 3/3/2017 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/183323 | 10/26/2017 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3244843 | Ross | Apr 1966 | A |
| 3469050 | Robinson | Sep 1969 | A |
| 4210790 | Kurosawa | Jul 1980 | A |
| 4588879 | Noda | May 1986 | A |
| 4926017 | Aoki | May 1990 | A |
| 6479778 | Kimura et al. | Nov 2002 | B1 |
| 6506992 | Kim | Jan 2003 | B2 |
| 8039771 | Trondsen | Oct 2011 | B2 |
| 8779317 | Kim | Jul 2014 | B2 |
| 20090184274 | Kikuchi et al. | Jul 2009 | A1 |
| 20120091101 | Kim | Apr 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 531 248 | Nov 1972 | CH |
| 4119191 | Dec 1992 | DE |
| 50-086678 | Jul 1975 | JP |
| 3812711 | Aug 2006 | JP |
| 2009170372 | Jul 2009 | JP |
| 2014127280 | Jul 2014 | JP |
| 2011104751 | Sep 2011 | WO |
| Entry |
|---|
| Translation of DE4119191 (original document published Dec. 17, 1992) (Year: 1992). |
| International Search Report (PCT/ISA/210) dated Jun. 6, 2017, by the Japanese Patent Office as the International Searching Authority for International Application No. PCT/JP2017/008423. |
| Extended European Search Report dated Feb. 13, 2019, issued by the European Patent Office in corresponding European Application No. 17785666.3. (10 pages). |
| Number | Date | Country | |
|---|---|---|---|
| 20190035578 A1 | Jan 2019 | US |
