Pole part

Abstract

The present invention relates to a pole part, comprising: - a vacuum interrupter (10); - a sealing lid (20); and - an overmolded plastic housing (90); wherein a stem of a moveable contact (50) of the vacuum interrupter is configured to move within an inner tube section of the sealing lid along a central axis of the inner tube section of the sealing lid, such that a central axis of the stem of the moveable contact is parallel to the central axis of the inner tube section of the sealing lid; wherein in a first configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid towards a fixed contact (70) of the vacuum interrupter to bring the moveable contact into contact with the fixed contact; wherein in a second configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid away from the fixed contact to space the moveable contact into from the fixed contact; wherein in the first configuration at least a part of the sealing lid is located between at least a first part of the stem of the moveable contact and at least a part of the overmolded plastic housing; and wherein in the second configuration the at least a part of the sealing lid is located between at least a second part of the stem of the moveable contact and the at least a part of the overmolded plastic housing.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a pole part.BACKGROUND OF THE INVENTION

[0002] Vacuum interupters for use in medium voltage applications are generally embedded into a polymeric material in an overmolding process.

[0003] To cover the thin metal upper lid of the vacuum interrupter and protect it against pressure and mechanical forces during the overmolding process a movable core is widely used inside the mold and a compensation ring is used to protect the top surface of the ceramic tube of the vacuum interrupter as the movable core provides a seal against the ceramic surface during the overmolding process.

[0004] Additionally, during subsequent installation, twisting and torques need to be applied to the movable contact and the stem of the movable contact. A bellows is connected to the stem of the movable contact, and this twisting and torque being applied to the stem of the movable contact can damage the bellows, and lead to ventilation of the vacuum interrupter. To absorb the forces that occur, an anti-twist protection device is inserted between the upper lid of the vacuum interrupter, bellows, and moving contact. This anti-twist protection device is fixed with snap rings against dropping out.

[0005] Thus, vacuum interrupters have a number of components to ensure correct operation and ensure that parts do not become damaged during an overmolding process of the vacuum interrupter to form a pole part. An anti-twist component is required for the stem of the movable contact to ensure that it does not rotate or twist about its axis in order to protect the bellows connected to the stem of the movable contact that cannot be subjected to torsional forces. A compensation component is required to protect the vacuum interrupter during the overmolding process.

[0006] Incorporation of these multiple components into a vacuum interrupter pole part increases costs due to numerous parts being required to be made, increases costs due to extra assembly steps required to be introduced.

[0007] There is a need to address these issues.SUMMARY OF THE INVENTION

[0008] Therefore, it would be advantageous to provide an improved pole part design that provides for improved operation of the vacuum interrupter of the pole part and provides for improved manufacturability of the pole part.

[0009] The object of the present invention is solved with the subject matter of the independent claim, wherein further embodiments are incorporated in the dependent claims.

[0010] In an aspect, there is provided a pole part, comprising: a vacuum interrupter (10); a sealing lid (20); and an overmolded plastic housing (90).

[0011] A stem of a moveable contact (50) of the vacuum interrupter is configured to move within an inner tube section of the sealing lid along a central axis of the inner tube section of the sealing lid, such that a central axis of the stem of the moveable contact is parallel to the central axis of the inner tube section of the sealing lid.

[0012] In a first configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid towards a fixed contact (70) of the vacuum interrupter to bring the moveable contact into contact with the fixed contact.

[0013] In a second configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid away from the fixed contact to space the moveable contact into from the fixed contact.

[0014] In the first configuration at least a part of the sealing lid is located between at least a first part of the stem of the moveable contact and at least a part of the overmolded plastic housing.

[0015] In the second configuration the at least a part of the sealing lid is located between at least a second part of the stem of the moveable contact and the at least a part of the overmolded plastic housing.

[0016] Thus, a new sealing lid is added to a vacuum interrupter, and both are overmolded in a plastic housing.

[0017] The sealing lid provides a guidance function for the moveable contact in order that the moveable contact can move accurately towards the fixed contact, ensuring that the contacts are correctly aligned as the vacuum interrupter closes to ensure integrity of the closing function. Thus, normally due to the assembly process of a vacuum interrupter, with respect to the bellows, the movable contact, the ceramic tube, and shielding, with only one soldering disc connecting everything, there is no ability to provide linear guidance of the movable contact. This lack of linear guidance of the movable contact leads to a higher load of the bellows and leads to an undefined concentricity of both context to each other that in turn leads to distortion of the electric field distribution and undefined striking distances. However, with the new sealing lid that provides guidance function for the movable contact, these issues are mitigated.

[0018] The sealing lid also provides an anti-twist function, where the moveable contact and the stem connected to the moveable contact are stopped from rotating, thereby protecting a bellows that is connected to the stem from being damaged as the bellows cannot be subjected to torsional forces. The sealing lid also provides a compensation function, where it protects a delicate metallic upper lid and the ceramic tube of the vacuum interrupter that can be damaged during the overmolding process where a movable core of the mold can be pushed hard against the ceramic tube in the overmolding process and damage the ceramic tube. But now the sealing lid, made from an appropriate plastic or other suitable material that is not as hard as metal, can act as an intermediate spacer between the movable core and the ceramic tube such that the movable core pushes against the forgiving sealing lid that then pushes against the ceramic tube during the overmolding process, and the forgiving sealing lid then doesn't damage the delicate ceramic tube during the overmolding process.

[0019] In an example, the sealing lid is configured to stop the stem of the moveable contact from moving laterally with respect to the central axis of the stem of the moveable contact, and / or the sealing lid is configured to stop the central axis of the stem of the moveable contact from rotating with respect to the central axis of the stem of the moveable contact such that the central axis of the stem of the moveable contact is no longer parallel to the central axis of the inner tube section of the sealing lid.

[0020] In an example, an inner cross section of the inner tube section of the sealing lid matches an outer cross section of the stem of the moveable contact.

[0021] In an example, the stem of the moveable contact is configured to move within an opening of an upper lid (30) of the vacuum interrupter, and the sealing lid is fixedly connected to the upper lid and / or the sealing lid is configured not to move with respect to the upper lid.

[0022] In an example, at least a part of the inner tube section of the sealing lid extends into the opening of the upper lid.

[0023] In an example, a first end of a bellows (40) of the vacuum interrupter is fixedly connected to the moveable contact around an outer surface of the stem of the moveable contact. A second end of the bellows is fixedly connected to the upper lid around the opening of the upper lid, and wherein at least a part of the inner tube section of the sealing lid extends into the bellows.

[0024] Thus, the sealing lid is arranged and shaped such that it maintains the stem of the moveable contact along a same centre axis as it moves towards and away from the fixed contact to ensure the integrity of closing and indeed of opening operations, as the moveable contact is correctly positioned with respect to the fixed contact during these operations.

[0025] In other words, the sealing lid acts as a guiding component for the stem of the movable contact to ensure that the moveable contact moves correctly towards and away from the fixed contact.

[0026] In an example, the sealing lid is configured to stop the stem of the moveable contact from rotating about the central axis of the stem of the moveable contact.

[0027] In an example, the inner cross section of the inner tube section of the sealing lid is non-circular.

[0028] In an example, the inner cross section of the inner tube section of the sealing lid is substantially polygonal shaped or elliptically shaped or slightly deformed circular shaped.

[0029] Thus, the the sealing lid is arranged and shaped such that the stem of the moveable contact cannot rotate about its axis. This means that the bellows that is connected to the stem of the moveable contact is protected because it is not then subjected to torsional forces.

[0030] In other words, the sealing lid acts as an anti-twist component for the stem of the movable contact to ensure that it does not rotate or twist about its axis in order to protect the bellows connected to the stem of the movable contact that cannot be subjected torsional forces

[0031] In an example, at least a part of the sealing lid is located between a side wall of the upper lid and a part of the overmolded plastic housing.

[0032] In an example, at least a part of the sealing lid is in contact with a ceramic tube (60) of the vacuum interrupter, or at least a part of the sealing lid is configured to come into contact with the ceramic tube (60) of the vacuum interrupter.

[0033] In an example, at least a part of the sealing lid is located between the upper lid and a ceramic tube (60) of the vacuum interrupter.

[0034] In an example, a main body of the sealing lid is located adjacent to a top surface of the upper lid, and the top surface of the upper lid faces away from the fixed contact.

[0035] Thus, the the sealing lid is arranged and shaped such that it protects the ceramic tube from being directly subjected to forces from the hard metallic lid during an overmolding process, rather the softer sealing lid made from plastic can conform to the ceramic tube such that forces from the metallic upper lid are applied uniformly to the delicate ceramic tube and not just to limited contact points, thus the magnitudes of applied forces per unit area are reduced and damage to the ceramic tube during the overmolding process is mitigated.

[0036] In other words, the sealing lid acts as a compensation component to protect the vacuum interrupter during the overmolding process.

[0037] In an example, the sealing lid comprises plastic.

[0038] In an example, the sealing lid comprises thermoplastic polymer.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Exemplary embodiments will be described in the following with reference to the following drawing: Fig. 1 shows an isometric view of an example of a sealing lid, where an inner tube section has an inner cross section that is circular; Fig. 2 shows a front view of an example of the sealing lid of Fig. 1; Fig. 3 shows a cut-through view of an example of the sealing lid of Fig. 1; Fig. 4 shows a top view of an example of the sealing lid of Fig. 1; Fig. 5 shows isometric, front and top views of a sealing lid, where an inner tube section has an inner cross section that is rectangular with rounded ends; Fig. 6 shows isometric, and top views of a sealing lid, where an inner tube section has an inner cross section that is hexagonal; Fig. 7 shows isometric, front, cut-through and top views of a sealing lid, where an inner tube section has an inner cross section that is substantially square; Fig. 8 shows an example of a pole part; and Fig. 9 shows an example of a pole part, that has been rotated through 180 degrees with respect to the pole part of Fig, 8. DETAILED DESCRIPTION OF EMBODIMENTS

[0040] Figs. 1-9 relate to a sealing lid 20 that is utilized with a vacuum interrupter 10 that has been overmolded with an overmolded plastic housing 90 to form a new pole part.

[0041] An exemplar pole part, comprises: a vacuum interrupter 10; a sealing lid 20; and an overmolded plastic housing 90.

[0042] A stem of a moveable contact (50) of the vacuum interrupter is configured to move within an inner tube section of the sealing lid along a central axis of the inner tube section of the sealing lid, such that a central axis of the stem of the moveable contact is parallel to the central axis of the inner tube section of the sealing lid.

[0043] In a first configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid towards a fixed contact (70) of the vacuum interrupter to bring the moveable contact into contact with the fixed contact.

[0044] In a second configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid away from the fixed contact to space the moveable contact into from the fixed contact.

[0045] In the first configuration at least a part of the sealing lid is located between at least a first part of the stem of the moveable contact and at least a part of the overmolded plastic housing.

[0046] In the second configuration the at least a part of the sealing lid is located between at least a second part of the stem of the moveable contact and the at least a part of the overmolded plastic housing.

[0047] Thus, a new sealing lid is added to a vacuum interrupter, and both are overmolded in a plastic housing.

[0048] The sealing lid provides a guidance function for the moveable contact in order that the moveable contact can move accurately towards the fixed contact, ensuring that the contacts are correctly aligned as the vacuum interrupter closes to ensure integrity of the closing function. Thus, normally due to the assembly process of a vacuum interrupter, with respect to the bellows, the movable contact, the ceramic tube, and shielding, with only one soldering disc connecting everything, there is no ability to provide linear guidance of the movable contact. This lack of linear guidance of the movable contact leads to a higher load of the bellows, and leads to an undefined concentricity of both context to each other that in turn leads to distortion of the electric field distribution and undefined striking distances. However, with the new sealing lid that provides guidance function for the movable contact, these issues are mitigated.

[0049] The sealing lid also provides an anti-twist function, where the moveable contact and the stem connected to the moveable contact are stopped from rotating, thereby protecting a bellows that is connected to the stem from being damaged as the bellows cannot be subjected to torsional forces. The sealing lid also provides a compensation function, where it protects a delicate ceramic tube of the vacuum interrupter than can be damaged during the overmolding process where a metallic upper lid of the vacuum interrupter can be pushed hard against the ceramic tube in the overmolding process and damage the ceramic tube. But now the sealing lid, made from an appropriate plastic or other suitable material that is not as hard as metal, can act as an intermediate spacer between the metallic upper lid and the ceramic tube such that the hard metallic lid pushes against the forgiving sealing lid that then pushes against the ceramic tube during the overholding process, and the forgiving sealing lid then doesn't damage the delicate ceramic tube during the overmolding process.

[0050] In an example, the sealing lid is configured to stop the stem of the moveable contact from moving laterally with respect to the central axis of the stem of the moveable contact, and / or the sealing lid is configured to stop the central axis of the stem of the moveable contact from rotating with respect to the central axis of the stem of the moveable contact such that the central axis of the stem of the moveable contact is no longer parallel to the central axis of the inner tube section of the sealing lid.

[0051] In an example, an inner cross section of the inner tube section of the sealing lid matches an outer cross section of the stem of the moveable contact.

[0052] In an example, the stem of the moveable contact is configured to move within an opening of an upper lid 30 of the vacuum interrupter, and the sealing lid is fixedly connected to the upper lid and / or the sealing lid is configured not to move with respect to the upper lid.

[0053] In an example, at least a part of the inner tube section of the sealing lid extends into the opening of the upper lid.

[0054] In an example, a first end of a bellows 40 of the vacuum interrupter is fixedly connected to the moveable contact around an outer surface of the stem of the moveable contact. A second end of the bellows is fixedly connected to the upper lid around the opening of the upper lid, and wherein at least a part of the inner tube section of the sealing lid extends into the bellows.

[0055] Thus, the sealing lid is arranged and shaped such that it maintains the stem of the moveable contact along a same centre axis as it moves towards and away from the fixed contact to ensure the integrity of closing and indeed of opening operations, as the moveable contact is correctly positioned with respect to the fixed contact during these operations.

[0056] In other words, the sealing lid acts as a guiding component for the stem of the movable contact to ensure that the moveable contact moves correctly towards and away from the fixed contact.

[0057] In an example, the sealing lid is configured to stop the stem of the moveable contact from rotating about the central axis of the stem of the moveable contact.

[0058] In an example, the inner cross section of the inner tube section of the sealing lid is non-circular.

[0059] In an example, the inner cross section of the inner tube section of the sealing lid is substantially polygonal shaped or elliptically shaped or slightly deformed circular shaped.

[0060] Thus, the sealing lid is arranged and shaped such that the stem of the moveable contact cannot rotate about its axis. This means that the bellows that is connected to the stem of the moveable contact is protected because it is not then subjected to torsional forces.

[0061] In other words, the sealing lid acts as an anti-twist component for the stem of the movable contact to ensure that it does not rotate or twist about its axis in order to protect the bellows connected to the stem of the movable contact that cannot be subjected torsional forces

[0062] In an example, at least a part of the sealing lid is located between a side wall of the upper lid and a part of the overmolded plastic housing.

[0063] In an example, at least a part of the sealing lid is in contact with a ceramic tube 60 of the vacuum interrupter, or at least a part of the sealing lid is configured to come into contact with the ceramic tube of the vacuum interrupter.

[0064] In an example, at least a part of the sealing lid is located between the upper lid and a ceramic tube 60 of the vacuum interrupter.

[0065] In an example, a main body of the sealing lid is located adjacent to a top surface of the upper lid, and the top surface of the upper lid faces away from the fixed contact.

[0066] Thus, the sealing lid is arranged and shaped such that it protects the ceramic tube from being directly subjected to forces from the hard metallic lid during an overmolding process, rather the softer sealing lid made from plastic can conform to the ceramic tube such that forces from the metallic upper lid are applied uniformly to the delicate ceramic tube and not just to limited contact points, thus the magnitudes of applied forces per unit area are reduced and damage to the ceramic tube during the overmolding process is mitigated.

[0067] In other words, the sealing lid acts as a compensation component to protect the vacuum interrupter during the overmolding process.

[0068] In an example, the sealing lid comprises plastic.

[0069] In an example, the sealing lid comprises thermoplastic polymer.

[0070] Thus, the new sealing ring achieves the following:A guidance function:

[0071] The movable contact 50 is connected to the bellows 40, which is in turn connected to the upper Vl-lid 30. Caused by the flexibility of the bellows 40 there is no guaranteed alignment of the fixed 70 and movable contact 50. The inner tube section of the sealing lid 20 prevents the movable contact 50 from being radially misaligned during movement.An anti-twist protection function:

[0072] The bellows 40 is not suited to withstand tangential shear forces when torques is applied to the movable contact 50. The inner tube section of the sealing lid 20 is shaped in such a way that form closure between the movable contact 50 and the sealing lid 20 is ensured. Therefore, occurring torques are transferred to the sealing lid 20.A compensation function:

[0073] The upper lid 30 and the lower lid 80 of the vacuum interrupter must be sealed during injection molding process of an overmolded plastic housing 90 to prevent a damage caused by high injection pressure. This is usually done by movable cores inside the injection mold. Because the metallic mold core could cause damage to the fragile ceramic tube 60 via the upper lid 30, the sealing lid 20 is placed between the ceramic tube 60 and the mold core (on top of the VI-lid) and transfers the applied forces of the mold via the upper lid 30 to the ceramic tube 60 like an elastic sealing. Thus, the sealing lid 20 equalizes tolerancing issues within the vacuum interrupter 10 and absorbs forces of the mold core to ceramic tube 60.Reference numerals

[0074] 10Vacuum interrupter 20Sealing lid 30Upper lid 40Bellows 50Moveable contact 60Ceramic tube 70Fixed contact 80Lower lid 90Overmolded plastic housing

Claims

1. A pole part, comprising: - a vacuum interrupter (10); - a sealing lid (20); and - an overmolded plastic housing (90); wherein a stem of a moveable contact (50) of the vacuum interrupter is configured to move within an inner tube section of the sealing lid along a central axis of the inner tube section of the sealing lid, such that a central axis of the stem of the moveable contact is parallel to the central axis of the inner tube section of the sealing lid; wherein in a first configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid towards a fixed contact (70) of the vacuum interrupter to bring the moveable contact into contact with the fixed contact; wherein in a second configuration the stem of the moveable contact has moved within the inner tube section of the sealing lid away from the fixed contact to space the moveable contact into from the fixed contact; wherein in the first configuration at least a part of the sealing lid is located between at least a first part of the stem of the moveable contact and at least a part of the overmolded plastic housing; and wherein in the second configuration the at least a part of the sealing lid is located between at least a second part of the stem of the moveable contact and the at least a part of the overmolded plastic housing.

2. Pole part according to claim 1, wherein the sealing lid is configured to stop the stem of the moveable contact from moving laterally with respect to the central axis of the stem of the moveable contact, and / or the sealing lid is configured to stop the central axis of the stem of the moveable contact from rotating with respect to the central axis of the stem of the moveable contact such that the central axis of the stem of the moveable contact is no longer parallel to the central axis of the inner tube section of the sealing lid.

3. Pole part according to any of claims 1-2, wherein an inner cross section of the inner tube section of the sealing lid matches an outer cross section of the stem of the moveable contact.

4. Pole part according to any of claims 1-3, wherein the stem of the moveable contact is configured to move within an opening of an upper lid (30) of the vacuum interrupter, and wherein the sealing lid is fixedly connected to the upper lid and / or wherein the sealing lid is configured not to move with respect to the upper lid.

5. Pole part according to claim 4, wherein at least a part of the inner tube section of the sealing lid extends into the opening of the upper lid.

6. Pole part according to any of claims 4-5, wherein a first end of a bellows (40) of the vacuum interrupter is fixedly connected to the moveable contact around an outer surface of the stem of the moveable contact, wherein a second end of the bellows is fixedly connected to the upper lid around the opening of the upper lid, and wherein at least a part of the inner tube section of the sealing lid extends into the bellows.

7. Pole part according to any of claims 1-8, wherein the sealing lid is configured to stop the stem of the moveable contact from rotating about the central axis of the stem of the moveable contact.

8. Pole part according to claim 7 when dependent upon claim 3 or when dependent upon claim 7 when dependent upon any of claims 4-6 when dependent upon claim 3, wherein the inner cross section of the inner tube section of the sealing lid is non-circular.

9. Pole part according to claim 8, wherein the inner cross section of the inner tube section of the sealing lid is substantially polygonal shaped or elliptically shaped or slightly deformed circular shaped.

10. Pole part according to claim 4 or any of claims 9-5 when dependent upon claim 4, wherein at least a part of the sealing lid is located between a side wall of the upper lid and a part of the overmolded plastic housing.

11. Pole part according to claim 4 or any of claims 10-5 when dependent upon claim 4, wherein at least a part of the sealing lid is in contact with a ceramic tube (60) of the vacuum interrupter, or wherein at least a part of the sealing lid is configured to come into contact with the ceramic tube (60) of the vacuum interrupter.

12. Pole part according to claim 11, wherein at least a part of the sealing lid is located between the upper lid and a ceramic tube (60) of the vacuum interrupter.

13. Pole part according to claim 4 or any of claims 12-5 when dependent upon claim 4, wherein a main body of the sealing lid is located adjacent to a top surface of the upper lid, wherein the top surface of the upper lid faces away from the fixed contact.

14. Pole part according to any of claims 1-13, wherein the sealing lid comprises plastic.

15. Pole part according to claim 14, wherein the sealing lid comprises thermoplastic polymer.

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