Vacuum valve, vacuum interrupter, and vacuum contactor

Abstract

To achieve both of a reduction and stability of a contact resistance value.SOLUTION: A vacuum valve comprises: a vacuum insulation container; a fixing side contactor provided into the vacuum insulation container; and a movable side contactor that is provided in the vacuum insulation container, and is contacted to or separated from the fixing side contactor. A first contact surface contacted to the fixing side contactor of the movable side contactor has a flat surface shape. A second contact surface contacted to the movable side contactor of the fixing side contactor has a spherical shape projected toward the movable side contactor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to vacuum valves, vacuum interrupters and vacuum contactors. [Background technology]

[0002] It is desirable for vacuum interrupters, which are used in vacuum circuit breakers and vacuum contactors that open and close frequently, to achieve both low contact resistance and stability. Conventional vacuum interrupters use a pair of disk-shaped contacts, and the current is opened and closed by the contact and opening of the contacts. In addition, vacuum interrupters with small rated capacity have been proposed that use contacts with spherical contact surfaces to obtain stable current-carrying performance with a small pressing force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4818530 [Patent Document 2] Patent No. 6039266 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a vacuum valve, a vacuum circuit breaker, and a vacuum contactor that can achieve both a reduction in contact resistance and stability. [Means for solving the problem]

[0005] The vacuum interrupter of the embodiment includes a vacuum insulating container, a fixed contactor provided in the vacuum insulating container, and a movable contactor provided in the vacuum insulating container and adapted to come into contact with and separate from the fixed contactor. A first contact surface of the movable contactor that comes into contact with the fixed contactor is flat. A second contact surface of the fixed contactor that comes into contact with the movable contactor is spherical and protrudes toward the movable contactor. [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a cross-sectional view showing a configuration example of a vacuum valve according to an embodiment. [Diagram 2] FIG. 13 is a graph showing an example of the relationship between the contact area and the contact resistance value. [Diagram 3] 11A and 11B are diagrams showing examples of the relationship between the radius of curvature of a contact and the contact area. [Figure 4] FIG. 11 is a diagram for explaining occurrence of slippage in a comparative example. [Diagram 5] FIG. 11 is a diagram for explaining occurrence of slippage in a comparative example. [Figure 6] 5A and 5B are diagrams for explaining force balance in the embodiment. [Figure 7] FIG. 1 is a diagram showing an example of the configuration of a vacuum circuit breaker using a vacuum valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the vacuum valve according to the present invention will be described in detail with reference to the accompanying drawings.

[0008] A vacuum interrupter (hereinafter referred to as the comparative example) has been proposed that uses contacts in which the contact surfaces of both the fixed electrode (hereinafter referred to as the fixed electrode) and the movable electrode (hereinafter referred to as the current-carrying electrode) are spherical. In the comparative example vacuum interrupter, in addition to the high contact surface pressure between the contacts, it is known that when the central axes of the fixed electrode and the movable electrode are eccentric, adhesions and holes up to about 50 μm in height are formed on the surface due to slippage (shear) on the contact surface.

[0009] Furthermore, if the adhered material and the hole cannot be brought into contact at the position where they match, the contact area is significantly reduced and the contact resistance increases. In addition, if the contact resistance increases, the current path becomes biased, the contact area becomes overheated, and the contact becomes welded, which can result in a decrease in interruption performance.

[0010] To stabilize the contact state, technology has been proposed that makes the shape of the contact surface flat. However, in a configuration where flat surfaces come into contact with each other, if the central axes of the fixed electrode and the movable electrode are offset, the fixed contactor (hereafter, fixed contactor) and the movable contactor (hereafter, movable contactor) will change from surface contact, where the entire contact surface is in contact, to point contact, where the contact surface is biased toward the periphery. In such a case, the contact area will decrease significantly, and the contact resistance will increase.

[0011] Another technique proposed for stabilizing the contact state is to make one of the contacts have a cone-shaped recess in the center, but this can increase manufacturing costs and cause quality variations.

[0012] In addition, the surface contact between the contacts as in the two technologies above leads to an increase in the peeling force when welding occurs. To suppress the peeling force, it is desirable for the contacts to be in point contact, as in the vacuum interrupter in the comparative example.

[0013] Thus, the challenge for vacuum valves that open and close frequently is to achieve both low contact resistance and stability. In order to reduce contact resistance, it is effective to increase the contact area when the contacts come into contact with each other. On the other hand, in order to maintain the stability of the contact resistance (contact state), it is effective to prevent wear and damage to the contact surface caused by contact between the contacts.

[0014] Therefore, in this embodiment, the contact surface of the contactor (fixed contactor) used for the fixed electrode of the vacuum interrupter is spherical (spherical shape), and the contact surface of the contactor (movable contactor) used for the movable electrode is flat (flat shape). This makes it possible to realize a vacuum interrupter with low contact resistance and stable contact resistance characteristics over a long period of time.

[0015] That is, the vacuum interrupter of this embodiment has a larger contact area than the comparative example, which uses spherical contacts, and therefore has a smaller contact resistance. Also, even if the movable electrode is inclined when in contact, the slippage (horizontal shear force) is small, so wear and damage on the contact surface are unlikely to occur. This makes the contact stable, and allows the contact resistance to be maintained for a long time.

[0016] In the following description, the movable electrode is assumed to move in the vertical direction and the slip direction is the horizontal direction. When the movable electrode is moved in the other direction DA, the slip direction is the direction DB perpendicular to the direction DA.

[0017] Fig. 1 is a cross-sectional view showing an example of the configuration of a vacuum interrupter 1 of this embodiment. As shown in Fig. 1, the vacuum interrupter 1 includes a vacuum insulating container 2, a fixed side sealing metal fitting 3, a movable side sealing metal fitting 4, a fixed side electrode 5, a fixed side contactor 6, a movable side contactor 7, a movable side electrode 8, a bellows cover 9, and a bellows 10.

[0018] The vacuum insulating container 2 is formed, for example, in a cylindrical shape. A fixed side sealing metal fitting 3 and a movable side sealing metal fitting 4 are sealed to the openings at both ends of the vacuum insulating container 2. A fixed side electrode 5 is fixed in a state in which it penetrates the fixed side sealing metal fitting 3. A fixed side contactor 6 is fixed to the end of the fixed side electrode 5 inside the vacuum insulating container 2. The contact surface (second contact surface) of the fixed side contactor 6 that comes into contact with the movable side contactor 7 is formed in a spherical shape that protrudes toward the movable side contactor 7.

[0019] The movable side electrode 8 is an electrode provided so as to penetrate the movable side sealing metal fitting 4. Opposite the fixed side contactor 6, the movable side contactor 7 which can be freely brought into contact with and separated from the fixed side contactor 6 is fixed to an end of the movable side electrode 8. The term "contact with and separation from" refers to contact and separation. That is, the movable side contactor 7 comes into contact with the fixed side contactor 6 or separates from the fixed side contactor 6 according to the movement of the movable side electrode 8. The contact surface (first contact surface) of the movable side contactor 7 which comes into contact with the fixed side contactor 6 is formed in a flat shape.

[0020] The degree of flatness of the contact surface of the movable contactor 7 may be determined so as to prevent wear and surface damage, for example. For example, the contact surface of the movable contactor 7 may be formed in a flat shape with a flatness of 0.1 mm or less.

[0021] A bellows cover 9 is provided at the middle of the movable electrode 8. A freely expandable bellows 10 is sealed between the bellows cover 9 and the movable sealing metal fitting 4. In addition, an arc shield 11 that surrounds the space between the fixed contactor 6 and the movable contactor 7 is fixed to the inner surface of the vacuum insulating container 2.

[0022] Each electrode (fixed electrode 5, movable electrode 8) and each contactor (fixed contactor 6, movable contactor 7) may be made of any material, but is preferably made of a composite material containing tungsten carbide (WC), cobalt (Co) and silver (Ag).

[0023] It has been found that the contact area when contactors come into contact with each other serves as an index for reducing the contact resistance value, which is one of the issues of this embodiment. Fig. 2 is a diagram showing an example of the relationship between the contact area and the contact resistance value. Fig. 2 shows an example of the relationship between the contact area and the contact resistance value when spherical surfaces with different radii of curvature come into contact with each other. As shown in Fig. 2, the larger the contact area, the lower the contact resistance value. The contact area can be calculated based on, for example, Hertz's contact theory.

[0024] In this embodiment, instead of a combination of spherical contacts as in the comparative example, a combination of a spherical fixed contact 6 and a planar movable contact 7 is used. This makes it possible to increase the contact area compared to the comparative example even with the same pressing force, and as a result, it becomes possible to reduce the contact resistance value.

[0025] 3 is a diagram showing an example of the relationship between the radius of curvature of the contact surface (surface) of a contact and the contact area. The radius of curvature represents the radius of curvature of a spherical contact. In the case of a combination of a flat contact and a spherical contact as in this embodiment, the contact area increases as the radius of curvature of the spherical contact becomes larger. On the other hand, in the case of a combination of two spherical contacts as in the comparative example, the contact area hardly increases even if the radius of curvature becomes larger.

[0026] In this embodiment, since one of the contacts is spherical, the contact form is point contact as in the comparative example, and therefore the peeling force required when welding occurs can be reduced compared to a technique in which the contacts are in surface contact.

[0027] The contact surface of the movable electrode 8 may be formed to have a countersunk portion in the center, which can, for example, increase the contact area.

[0028] Another objective of this embodiment is to stabilize the contact resistance value, and it is effective to prevent wear and damage to the contact surface. This is because the inventors' previous research has shown that vacuum interrupters with increased contact resistance have damaged contact surfaces due to wear (the formation of minute irregularities). Previous research has also shown that slippage that occurs when contacts come into contact with each other is a condition that causes damage to the surface.

[0029] In a configuration in which the same spherical contacts are used on both the fixed and movable sides, as in the comparative example, if the central axis of the movable electrode is eccentric, the horizontal components of the contact load and reaction force will not be balanced at the contact point, and slippage (shear) will be likely to occur on the contact surface.

[0030] FIG. 4 is a diagram for explaining occurrence of slippage in the comparative example. As shown in FIG. 4, a spherical movable contactor 7b is used in the comparative example. In such a configuration, the load F (contact load) applied to the movable electrode 8 includes a horizontal component depending on the eccentricity of the central axis. Meanwhile, the reaction force N from the fixed electrode 5 includes no horizontal component or includes a horizontal component smaller than the load F. For this reason, the horizontal components of the load F and the reaction force N are not balanced, and slippage (shear) is likely to occur on the contact surface.

[0031] FIG. 5 is a diagram for explaining the occurrence of slippage in another comparative example. In the comparative example in FIG. 5, the fixed contactor 6b is planar, and the movable contactor 7b is spherical. In this configuration, the load F contains a horizontal component depending on the eccentricity of the central axis. Meanwhile, the reaction force N from the fixed electrode 5 contains no horizontal component or contains a horizontal component smaller than the load F. For this reason, the horizontal components of the load F and the reaction force N are not balanced, and slippage (shear) is likely to occur on the contact surface.

[0032] In contrast, in this embodiment, the fixed contactor 6 is spherical, and the horizontal components of the contact load and reaction force are easily balanced at the contact point even if the central axis of the movable electrode 8 is eccentric. Therefore, slippage (shear) is unlikely to occur on the contact surface.

[0033] Fig. 6 is a diagram for explaining the balance of forces in this embodiment. As shown in Fig. 6, in this embodiment, not only the load F but also the reaction force N from the fixed electrode 5 includes a horizontal component in response to the eccentricity of the central axis. Therefore, the horizontal components of the load F and the reaction force N are easily balanced, and slippage (shear) is unlikely to occur on the contact surface.

[0034] The radius of curvature of the fixed contactor 6 may be determined so that the contact area is an appropriate value. For example, the radius of curvature of the fixed contactor 6 may be set to a value equal to or greater than the length of the movable electrode 8 in the movable direction. This makes it possible to suppress slippage (shear) on the contact surface even if, for example, the central axis of the movable electrode 8 is eccentric.

[0035] The vacuum valve 1 of this embodiment may be used in any type of equipment, and can be used, for example, as a component of a vacuum circuit breaker and a vacuum contactor. Fig. 7 is a diagram showing a configuration example of a vacuum circuit breaker 100 using the vacuum valve 1. Since a vacuum contactor has a similar configuration to a vacuum circuit breaker, Fig. 7 can also be interpreted as a configuration example of the vacuum contactor 100.

[0036] 7, the vacuum circuit breaker 100 includes an operation mechanism unit 110 and an interrupter unit 120. The operation mechanism unit 110 includes an operation mechanism 111. The interrupter unit 120 includes a vacuum interrupter 1 and a rod 121. The operation mechanism 111 moves a movable electrode 8 of the vacuum interrupter 1 via the rod 121.

[0037] Although one vacuum valve 1 is shown in Fig. 7, the vacuum circuit breaker 100 may include multiple (e.g., three) vacuum valves 1. The configuration in Fig. 7 is only an example, and the vacuum valve 1 may be used in a vacuum circuit breaker (vacuum contactor) having any configuration other than that in Fig. 7.

[0038] In this manner, in the vacuum interrupter of the embodiment, the contact surface of the fixed contactor is spherical and the contact surface of the movable contactor is planar, thereby achieving both a reduction in contact resistance and stability.

[0039] A configuration example of the embodiment will be described below. (Configuration example 1) A vacuum insulating container; a fixed contact provided in the vacuum insulating container; a movable contactor provided in the vacuum insulating container and adapted to come into contact with and separate from the fixed contactor; a first contact surface of the movable contactor that contacts the fixed contactor is flat; A second contact surface of the fixed contactor that contacts the movable contactor is spherical and protrudes toward the movable contactor. Vacuum valve. (Configuration example 2) The fixed contact and the movable contact are formed of a composite material including tungsten carbide (WC), cobalt (Co) and silver (Ag). The vacuum interrupter according to configuration example 1. (Configuration example 3) The first contact surface is flat with a flatness of within 0.1 mm. 3. The vacuum interrupter according to configuration example 1 or 2. (Configuration Example 4) The first contact surface has a countersunk portion at the center. The vacuum valve according to any one of configuration examples 1 to 3. (Configuration Example 5) the second contact surface has a radius of curvature equal to or greater than the length in the moving direction of the movable electrode to which the movable contactor is fixed; 5. The vacuum valve according to any one of configuration examples 1 to 4. (Configuration Example 6) A vacuum circuit breaker comprising the vacuum valve according to any one of configuration examples 1 to 5. (Configuration Example 7) A vacuum contactor comprising the vacuum valve according to any one of configuration examples 1 to 5.

[0040] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0041] 1 Vacuum valve 2. Vacuum insulated vessel 3 Fixed side sealing metal fitting 4 Movable side sealing metal fitting 5 Fixed side electrode 6 Fixed side contact 7 Movable contact 8 Movable side electrode 9 Bellows cover 10 Bellows 11 Arc Shield

Claims

1. A vacuum insulating container; a fixed contact provided in the vacuum insulating container; a movable contactor provided in the vacuum insulating container and adapted to come into contact with and separate from the fixed contactor; a first contact surface of the movable contact that contacts the fixed contact is flat, a second contact surface of the fixed contactor that contacts the movable contactor has a spherical shape that protrudes toward the movable contactor; Vacuum valve.

2. The fixed contact and the movable contact are formed of a composite material containing tungsten carbide (WC), cobalt (Co) and silver (Ag).

2. The vacuum valve according to claim 1.

3. The first contact surface is flat with a flatness of within 0.1 mm.

2. The vacuum valve according to claim 1.

4. The first contact surface has a counterbore at a center portion.

2. The vacuum valve according to claim 1.

5. the second contact surface has a radius of curvature equal to or greater than the length in the moving direction of the movable electrode to which the movable contactor is fixed; 2. The vacuum valve according to claim 1.

6. A vacuum circuit breaker comprising the vacuum valve according to claim 1.

7. A vacuum contactor comprising the vacuum valve of claim 1.

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