Vacuum relay

Abstract

A vacuum relay 1 has a ceramic tube 2, a common terminal 3, an a-contact terminal 4, a b-contact terminal 5, and a movable terminal 7. The movable terminal 7 is housed in the ceramic tube 2, and enables conduction between the common terminal 3 and the a-contact terminal 4 or conduction between the common terminal 3 and the b-contact terminal 4. One of the common terminal 3, the a-contact terminal 4, and the b-contact terminal 5 is disposed at one end of the ceramic tube 2.

Description

Vacuum relay

[0001] The present invention relates to a miniaturized vacuum relay suitable for switching power supply circuits such as semiconductor manufacturing equipment.

[0002] As a vacuum relay used in a power supply circuit, for example, there is a relay device of a c-contact relay system disclosed in Patent Document 1. This relay device is composed of a ceramic tube provided with an a-contact terminal, a b-contact terminal, and a c-contact terminal which is a common terminal thereof. In a vacuum chamber inside this ceramic tube, a movable terminal is arranged between the a-contact terminal and the b-contact terminal, and the a-contact terminal and the c-contact terminal are conducted or the b-contact terminal and the c-contact terminal are conducted through this movable terminal. The movable terminal is supported by an insulating rod, and the power supply circuit is switched by the operation of the insulating rod by a driving unit.

[0003] The a-contact terminal, the b-contact terminal, and the c-contact terminal ensure an atmospheric surface insulation distance corresponding to the withstand voltage on the atmospheric side of the ceramic tube. The diameter of the ceramic tube is set on the condition that the diameters of the respective terminals arranged in the radial direction thereof and the atmospheric surface insulation distance between the terminals are ensured. In particular, the diameter of the ceramic tube of Patent Document 1 is set such that the atmospheric surface insulation distance between the a-contact terminal and the b-contact terminal is larger than the atmospheric surface insulation distance between the a-contact terminal and the c-contact terminal and the atmospheric surface insulation distance between the b-contact terminal and the c-contact terminal.

[0004] Japanese Patent Application Laid-Open No. 2020-47492

[0005] In recent years, further miniaturization of semiconductor manufacturing equipment and the like has been demanded, and the requirement for miniaturization of its component, the vacuum relay, has been intensifying. Since the diameter of the ceramic tube, which has a great influence on the dimensions of the vacuum relay, needs to be set large so as to ensure the atmospheric surface insulation distance between the terminals arranged in the radial direction of the ceramic tube, the miniaturization of the vacuum relay is restricted.

[0006] In view of the above circumstances, an object of the present invention is to reduce the diameter of the ceramic tube of the vacuum relay to achieve miniaturization of the vacuum relay.

[0007] One aspect of the present invention is a vacuum relay having a common terminal, an a-contact terminal, a b-contact terminal, a movable terminal that enables conductivity between the common terminal and the a-contact terminal or between the common terminal and the b-contact terminal, and a ceramic tube housing the movable terminal. One of the common terminal, the a-contact terminal, or the b-contact terminal is located at one end of the ceramic tube.

[0008] In one aspect of the present invention, in the vacuum relay, two terminals other than the one terminal are arranged on the side wall of the ceramic tube.

[0009] In one aspect of the present invention, in the vacuum relay, one end of the two terminals faces the other inside the ceramic tube.

[0010] In one aspect of the present invention, the vacuum relay is configured such that an uneven surface is formed on the side wall.

[0011] In one aspect of the present invention, in the vacuum relay, one terminal is arranged at one end coaxially with the ceramic tube via a flange portion made of ceramic.

[0012] According to the present invention described above, the diameter of the ceramic tube of the vacuum relay can be reduced, making it possible to miniaturize the vacuum relay.

[0013] A schematic cross-sectional view of a vacuum relay according to Embodiment 1 of the present invention. A schematic cross-sectional view of a vacuum relay according to Embodiment 2 of the present invention. A schematic cross-sectional view of a vacuum relay according to Embodiment 3 of the present invention. A schematic cross-sectional view showing an example of a terminal arranged at one end of the ceramic tube of a vacuum relay according to one aspect of the present invention.

[0014] Embodiments of the present invention will be described below with reference to the drawings.

[0015] The vacuum relay 1 of Embodiment 1, one aspect of the present invention shown in Figure 1, is based on a c-contact relay system, and one of the following terminals—a common terminal 3, an a-contact terminal 4, or a b-contact terminal 5—is arranged at one end of the ceramic tube 2. This embodiment aims to reduce the size of the ceramic tube 2 in the radial direction while ensuring the creepage insulation distance in the atmosphere between the common terminal 3, the a-contact terminal 4, and the b-contact terminal 5.

[0016] The vacuum relay 1 comprises a ceramic tube 2, a common terminal 3, a contact terminal 4, a contact terminal 5, a drive unit 6, a movable terminal 7, and an insulating rod 8.

[0017] The ceramic tube 2 is cylindrical in shape, such as a cylindrical body, and houses the movable terminal 7, the insulating rod 8, and the base portion 9 of the drive unit 6. It is vacuum-sealed by the a-contact terminal 4, the b-contact terminal 5, the common terminal 3, and the drive unit 6. One of the a-contact terminal 4, b-contact terminal 5, or common terminal 3 is located at one end of the ceramic tube 2. In the illustrated configuration, the common terminal 3 is located at the upper end 23 of the ceramic tube 2, while the a-contact terminal 4 and b-contact terminal 5 are located on the side wall 21 of the ceramic tube 2. The outer surface of the side wall 21 has a pleated, uneven surface 22.

[0018] The common terminal 3 is located at the upper end 23, which is one end of the ceramic tube 2, and is electrically connected to the a-contact terminal 4 or the b-contact terminal 5 via the movable terminal 7 inside the ceramic tube 2. The common terminal 3 consists of a flange portion 31 that is brazed to the upper end 23 of the ceramic tube 2 to seal the opening of the upper end 23, and a terminal body portion 32 that is arranged coaxially with the ceramic tube 2 at the center of the flange portion 31, with the outer surface near one end in contact with the movable terminal 7.

[0019] The a-contact terminal 4 is positioned approximately midway along the side wall 21 of the ceramic tube 2, penetrating the side wall 21 in the radial direction of the ceramic tube 2. One end of the a-contact terminal 4 faces one end of the b-contact terminal 5 inside the ceramic tube 2, and it is capable of electrical communication with the b-contact terminal 5 via the movable terminal 7.

[0020] The b-contact terminal 5 is positioned approximately midway along the side wall 21 of the ceramic tube 2, penetrating the side wall 21 in the radial direction of the ceramic tube 2. One end of the b-contact terminal 5 faces one end of the a-contact terminal 4 inside the ceramic tube 2, and it is capable of electrical communication with the a-contact terminal 4 via the movable terminal 7.

[0021] The drive unit 6 is brazed to the lower end 24, which is the other end of the ceramic tube 2, and allows the base portion 9, on which the insulating rod 8 is erected, to be positioned at an angle or horizontally within the ceramic tube 2. The base portion 9 is made of a metal member that receives the magnetic force of the coil 61 of the drive unit 6, and can be positioned at an angle within the ceramic tube 2 due to the repulsive force of the spring 62 of the drive unit 6, or it can be positioned approximately horizontally by energizing the coil 61 by energizing the drive unit 6.

[0022] The movable terminal 7 is housed in a vacuum chamber within the ceramic tube 2 and enables conductivity between the common terminal 3 and the a-contact terminal 4 or between the common terminal 3 and the b-contact terminal 5 through the movement of the insulating rod 8. The movable terminal 7 is made of a conductive plate material (for example, a molybdenum plate) with a bent U-shaped cross-section and contacts the outer surface near one end of the terminal body portion 32 of the common terminal 3, and is capable of contacting either the a-contact terminal 4 or the b-contact terminal 5. A hole 71 into which the insulating rod 8 is inserted is formed in the lower part of the movable terminal 7.

[0023] The insulating rod 8 is erected on the base portion 9 and inserted into the hole 71 of the movable terminal 7. The movable terminal 7 is operated in conjunction with the horizontal or inclined positioning of the base portion 9, thereby making the common terminal 3 and the a-contact terminal 4 or the common terminal 3 and the b-contact terminal 5 electrically connected. At the upper end of the insulating rod 8, there is an insertion portion 81 that is inserted into the hole 71 of the movable terminal 7, and a support surface 82 that supports the movable terminal 7 around this insertion portion 81.

[0024] An example of the operation of the vacuum relay 1 will be explained with reference to Figure 1.

[0025] When the coil 61 of the drive unit 6 is not energized, the base portion 9 tilts due to the repulsive force of the spring 62, causing the insulating rod 8 to tilt and the movable terminal 7 to contact the b-contact terminal 5, thus creating electrical conductivity between the common terminal 3 (terminal body portion 32) and the b-contact terminal 5.

[0026] When the coil 61 of the drive unit 6 is energized, the magnetic force of the coil 61 causes the base portion 9 to become horizontal and the insulating rod 8 to be positioned vertically, causing the movable terminal 7 to contact the normally open contact terminal 4, thus creating electrical conductivity between the common terminal 3 (terminal body portion 32) and the normally open contact terminal 4.

[0027] In the vacuum relay 1 described above, one terminal (common terminal 3) of the c-contact relay is located at the upper end 23 of the ceramic tube 2, and the other two terminals (a-contact terminal 4, b-contact terminal 5) of the c-contact relay are located facing each other radially in the ceramic tube 2 at the midpoint of the side wall 21. In this configuration, the creepage insulation distance in the atmosphere between the one terminal and the other two terminals is secured along the height direction of the ceramic tube 2, and two creepage insulation distances in the atmosphere via the other two terminals are secured along the outer circumference of the ceramic tube 2. Therefore, the outer circumference of the ceramic tube 2 can be utilized efficiently, and the outer diameter of the ceramic tube 2 can be reduced.

[0028] In particular, the outer diameter of the ceramic tube 2 of the vacuum relay 1 is the value obtained by dividing the sum of the outer diameters of the two contact terminals + the sum of the creepage insulation distance in air between the two contact terminals by pi.

[0029] On the other hand, the outer diameter of a ceramic tube in a conventional vacuum relay, in which three contact terminals are arranged on the outer circumference of the ceramic tube, is the value obtained by dividing the sum of the outer diameters of the three contact terminals (a-contact terminal, b-contact terminal, and c-contact terminal) + (the sum of the creepage insulation distance in air between the three contact terminals) by pi.

[0030] Furthermore, the outer diameter of the ceramic tube of the vacuum relay disclosed in Patent Document 1 is the value obtained by dividing the sum of the outer diameters of the three contact terminals (a-contact terminal, b-contact terminal, and c-contact terminal) + (the creepage insulation distance in air between two contact terminals (a-contact terminal and b-contact terminal)) + (the creepage insulation distance in air between the other contact terminal (c-contact terminal) and the two contact terminals) × 2 by pi.

[0031] Therefore, according to the vacuum relay of the present invention, the outer diameter of the ceramic tube 2 can be reduced to about two-thirds of that of a conventional vacuum relay, and to about half of that of the vacuum relay described in Patent Document 1.

[0032] In Embodiment 1, the a-contact terminal 4 and the b-contact terminal 5 are arranged on the side wall 21 facing each other in the radial direction of the ceramic tube 2. However, depending on the internal structure of the ceramic tube 2, the same effect as in Embodiment 1 can be obtained even if they are arranged in close proximity to each other on the side wall 21.

[0033] The vacuum relay of the present invention is not limited to the vacuum relay 1 of Embodiment 1 in Figure 1. Alternatively, as in the vacuum relay 1 of Embodiment 2 in Figure 2, a b-contact terminal 5 may be arranged on the upper end 23 of the ceramic tube 2, and a common terminal 3 and an a-contact terminal 4 may be arranged on the side wall 21 of the ceramic tube 2.

[0034] In the vacuum relay 1 of Embodiment 2, when the coil 61 of the drive unit 6 is not energized, the insulating rod 8 tilts as the base portion 9 tilts due to the repulsive force of the spring 62, and electrical conductivity is established between the common terminal 3 on the side wall 21 side and the b-contact terminal 5 on the upper end 23 side via the movable terminal 7. When the coil 61 of the drive unit 6 is energized, the base portion 9 becomes horizontal due to the magnetic force of the coil 61, and the insulating rod 8 is positioned vertically, so that electrical conductivity is established between the common terminal 3 on the side wall 21 side and the a-contact terminal 4 of the ceramic tube 2 via the movable terminal 7. The movable terminal 7 and its hole 71 are formed by processing the plate material in such a way.

[0035] Alternatively, as shown in the third embodiment of the vacuum relay 1 in Figure 3, the a-contact terminal 4 may be placed on the upper end 23 of the ceramic tube 2, and the common terminal 3 and b-contact terminal 5 may be placed on the side wall 21 of the ceramic tube 2.

[0036] In the vacuum relay 1 of Embodiment 3, when the coil 61 of the drive unit 6 is not energized, the insulating rod 8 tilts as the base portion 9 tilts due to the repulsive force of the spring 62, and electrical conductivity is established between the common terminal 3 on the side wall 21 side and the b-contact terminal 5 via the movable terminal 7. When the coil 61 of the drive unit 6 is energized, the base portion 9 becomes horizontal due to the magnetic force of the coil 61, and the insulating rod 8 is positioned vertically, so electrical conductivity is established between the common terminal 3 on the side wall 21 side and the a-contact terminal 4 on the upper end 23 side via the movable terminal 7. The movable terminal 7 and its hole 71 are formed by processing the plate material in such a manner.

[0037] It is clear that the vacuum relay 1 of Embodiments 2 and 3 described above can achieve the same effects as the vacuum relay 1 of Embodiment 1.

[0038] The side wall 21 of the ceramic tube 2 has a recessed portion 22 formed for the vacuum relay 1. The recessed portion 22 is formed when the vacuum relay 1 is used under high voltage conditions, but it is not necessary to form the recessed portion 22 when it is used under low voltage conditions. Since the vacuum insulation inside the ceramic tube 2 has a high voltage resistance configuration, there is no need to change the internal structure of the ceramic tube 2, and components can be shared by changing only the structure on the atmospheric side.

[0039] In addition, in the vacuum relay 1 of embodiments 1, 2, and 3, the common terminal 3, a-contact terminal 4, and b-contact terminal 5 arranged at the upper end 23 of the ceramic tube 2 may be formed in a columnar shape coaxial with the ceramic tube 2, as illustrated in Figure 4. These columnar common terminal 3, a-contact terminal 4, and b-contact terminal 5 are brazed to the upper end 23 of the ceramic tube 2 via a flange portion 25 made of ceramic coaxial with the ceramic tube 2. According to the vacuum relay 1 of this embodiment, the creepage insulation distance in the atmosphere between the single contact terminal arranged at the upper end 23 of the ceramic tube 2 and the two contact terminals arranged on the side wall 21 of the ceramic tube 2 is increased, thereby improving the withstand voltage of embodiments 1, 2, and 3.

[0040] 1... Vacuum relay 2... Ceramic tube, 21... Side wall, 22... Uneven part, 23... Upper end, 24... Lower end, 25... Flange part 3... Common terminal, 31... Flange part, 32... Terminal body part 4... a-contact terminal 5... b-contact terminal 6... Drive unit, 61... Coil, 62... Spring 7... Movable terminal, 71... Hole 8... Insulating rod, 81... Insertion part, 82... Support surface 9... Base part

Claims

1. A vacuum relay comprising: a common terminal; an a-contact terminal; a b-contact terminal; a movable terminal that enables conductivity between the common terminal and the a-contact terminal or between the common terminal and the b-contact terminal; and a ceramic tube housing the movable terminal, wherein one of the common terminal, the a-contact terminal, or the b-contact terminal is located at one end of the ceramic tube.

2. The vacuum relay according to claim 1, characterized in that two terminals other than the one terminal are arranged on the side wall of the ceramic tube.

3. The vacuum relay according to claim 2, characterized in that one end of the two terminals faces the other inside the ceramic tube.

4. The vacuum relay according to claim 2, characterized in that the side wall has an uneven surface.

5. The vacuum relay according to claim 1, characterized in that one of the terminals is arranged at one end coaxially with the ceramic tube via a flange portion made of ceramic.

Images