Contact pin and pipe contact, and method for production

Abstract

A contact pin for a high-voltage and/or medium-voltage switch includes a contact tip of arc-erosion resistant material, a tubular support sleeve connected to the contact tip and a support core in the sleeve. The contact tip is in a forward region of the contact pin where arcs arise during use. The sleeve is in a rearward region of the contact pin, adjoining the forward region, where no arcs arise during use. A pipe contact includes an arc-erosion resistant annular contact and a support pipe connected to the annular contact. The annular contact is in a forward region of the pipe contact where arcs arise during use, and the support pipe is in a rearward region of the pipe contact, adjoining the forward region, where no arcs arise during use. Methods for producing a contact pin and a pipe contact are also provided.

Claims

1. A contact pin for at least one of a high-voltage switch or a medium-voltage switch, the contact pin comprising: a forward region of the contact pin in which arcs arise during use of the contact pin; a rearward region of the contact pin in which no arcs arise during use of the contact pin, said rearward region adjoining said forward region; a contact tip disposed in said forward region and formed of an arc-erosion resistant material; a tubular support sleeve connected to said contact tip and disposed in said rearward region, said support sleeve being formed of a material selected from the group consisting of a refractory metal, an alloy based on a refractory metal and steel; and a support core disposed in and connected to said support sleeve.

2. The contact pin according to claim 1, wherein said contact tip is formed of a material, and said support sleeve is formed of a material having lesser density than said contact-tip material.

3. The contact pin according to claim 1, wherein said support sleeve is formed of a material, and said support core is formed of a material having lesser density than said support sleeve material.

4. The contact pin according to claim 1, wherein: said contact tip, said support sleeve and said support core are formed of respective materials; said support sleeve material has lesser density than said contact-tip material; and said support core material has lesser density than said support sleeve material.

5. The contact pin according to claim 1, wherein said support core has higher electrical conductivity than said support sleeve.

6. The contact pin according to claim 1, wherein said support sleeve has an external radius, and said support sleeve has a wall thickness of between 5% and 25% of said external radius.

7. The contact pin according to claim 1, wherein said support sleeve has an external radius, and said support sleeve has a wall thickness of between 15% and 18%, of said external radius.

8. The contact pin according to claim 1, wherein said contact tip is formed of at least one refractory metal or a refractory-metal alloy having a refractory-metal content by mass of 90% by weight or more.

9. The contact pin according to claim 8, wherein said at least one refractory metal is tungsten or molybdenum.

10. The contact pin according to claim 1, wherein said support core is formed of a material selected from the group consisting of copper, aluminum, an alloy based on copper or aluminum and steel.

11. The contact pin according to claim 1, wherein: said support core is formed of a material selected from the group consisting of copper, aluminum, an alloy based on copper or aluminum and steel.

12. The contact pin according to claim 1, wherein said support sleeve and said support core are interconnected in a materially integral manner.

13. The contact pin according to claim 1, wherein said support core is integrally cast in said support sleeve.

14. A method for producing a pipe contact, the method comprising the following steps: providing an arc-erosion resistant annular contact in a forward region of the pipe contact in which arcs arise during use of the pipe contact; providing a support pipe in a rearward region of the pipe contact in which no arcs arise during use of the pipe contact, the rearward region adjoining the forward region, the support pipe being formed of a material selected from the group consisting of a refractory metal, an alloy based on a refractory metal and steel; axially aligning the support pipe and the annular contact; collectively infiltrating and interconnecting the annular contact and the support pipe; and machining the interconnected annular contact and support pipe to form a receptacle opening for receiving a contact pin according to claim 1.

15. A method for producing a contact pin, the method comprising the following steps: providing a contact tip formed of an arc-erosion resistant material in a forward region of the contact pin in which arcs arise during use of the contact pin; providing a tubular support sleeve in a rearward region of the contact pin in which no arcs arise during use of the contact pin, the rearward region adjoining the forward region, the support sleeve being formed of a material selected from the group consisting of a refractory metal, an alloy based on a refractory metal and steel; connecting the support sleeve to the contact tip; and providing a support core material disposed in or to be disposed in the support sleeve, forming a support core in the support sleeve.

16. A pipe contact for receiving a contact pin according to claim 1, the pipe contact comprising: a forward region of the pipe contact in which arcs arise during use of the pipe contact; a rearward region of the pipe contact in which no arcs arise during use of the pipe contact, said rearward region adjoining said forward region; an arc-erosion resistant annular contact disposed in said forward region of the pipe contact; and a support pipe connected to said annular contact and disposed in said rearward region of the pipe contact, said support pipe being formed of a material selected from the group consisting of a refractory metal, an alloy based on a refractory metal and steel.

17. The pipe contact according to claim 16, wherein said support pipe has a lesser wall thickness than said annular contact, and said support pipe has an internal diameter corresponding to an internal diameter of said annular contact.

18. The pipe contact according to claim 16, wherein said support pipe has a lesser wall thickness than said annular contact, and said support pipe has an external diameter corresponding to an external diameter of said annular contact.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Exemplary embodiments of the invention will be explained in more detail by means of the figures in which:

(2) FIGS. 1a-c show schematic illustrations of the individual components of a contact pin before and after assembly, in a sectional side view;

(3) FIGS. 2a-b show schematic illustrations of the components of a pipe contact according to a first design embodiment, before and after infiltration and post-machining;

(4) FIGS. 3a-b show schematic illustrations of the components of a pipe contact according to a second design embodiment, before and after infiltration and post-machining; and

(5) FIG. 4 shows a schematic illustration of an alternative design embodiment of a contact pin in a sectional side view.

DESCRIPTION OF THE INVENTION

(6) FIGS. 1a-c schematically and in a sectional side view show the components of a contact pin 2 during production. The contact pin 2 is constructed from a contact tip 4, a support sleeve 6, and a support core 8.

(7) When the contact pin 2 is used in a high-voltage switch the contact tip 4 contacts a pipe contact 10a-b (FIGS. 2a-b and 3a-b) so as to close the switch contact. The contact tip 4 is produced from an arc resistant or arc-erosion resistant material, respectively, such that the contact tip 4 or the contact pin 2, respectively, is not damaged by the arcs which arise during a switching procedure. For example, WCu 80/20 (Cu: 20% by weight) may be used as a contact-tip material. The contact tip 4 extends across the entire forward region of the contact pin 2 in which arcs may arise during a switching procedure. Respectively, the contact pin 4 in the axial direction A (movement direction) has an extent/length which guarantees that arcs which arise during use are limited to the contact tip 4.

(8) The tubular support sleeve 6 is disposed so as to directly adjoin the contact tip 4 and is connected to the contact tip 4 by means of electron-beam welding, for example. The connection between the contact tip 4 and the support sleeve may preferably be established during integral-casting of the support core 8. The support sleeve 6 is disposed in a region of the contact pin 2 in which no arcs arise during use, the support sleeve 6 being disposed outside the region in which arcs may arise, respectively. Therefore, the support sleeve 6 may be produced from a material which is not arc resistant but is (only) heat resistant and resistant to hot gases which are created by virtue of the arcs during switching procedures. In particular, more cost-effective materials may be used such that the production costs of the contact pin 2 are reduced. Additionally, materials of lesser density may be used for the support sleeve 6, such that the total weight of the contact pin 2 is reduced, on account of which in turn a drive for the contact pin 2 is stressed to a lesser extent, or a more cost-effective drive having less output may be used. For example, molybdenum, tungsten, or another refractory metal, or an alloy based on a refractory metal, may be used for the support sleeve 6. A further alternative is steel which is conceived for withstanding the high temperatures (up to approx. 1000 C., for example). The support sleeve 6 may be provided as a seamless (ready-made) pipe, for example. Alternatively, a flat sheet metal may be simply bent and welded to form a pipe or a hollow cylinder, respectively.

(9) Once the support sleeve 6 has been fastened to or even just positioned on the contact tip 4, respectively, (FIG. 1b), in a next step the support sleeve 6 is cast such that a support core 8 is configured in the support sleeve 6. The support core 8 is produced from a material having good electrical conductivity, for example copper, aluminum, or a respective alloy based on copper/aluminum, for example CuCr1Zr. The support core 8 having good electrical conductivity improves the electrical conductivity of the contact pin 2. By casting the support core 8 inside the sleeve 6, the sleeve 6, the contact tip 4, and the core 8 are interconnected in a stable manner. In particular, the support core 8 by way of the open end of the sleeve 6 (toward the contact tip 4) is in direct contact with the contact tip 4 such that a connection having good conductivity is provided between the tip 4 and the core 8. When a comparatively soft core material is used, the sleeve 6 stabilizes or supports the support core 8, respectively.

(10) As can be seen in FIG. 1c, the support core 8 protrudes somewhat beyond the open end of the sleeve 6 so as to guarantee that the contact pin 2 may be reliably installed in a respective switch or be connected to a support (not illustrated), preferably by means of electron-beam welding. Alternatively, the core 8 terminates so as to be flush with the sleeve 6.

(11) FIG. 4 shows a schematic illustration of an alternative design embodiment of a contact pin 2. In as far as not stated to the contrary, the function and use of the elements of the contact pin 2 which will be described hereunder correspond to those of the contact pin 2 which has been described in the context of FIGS. 1a-c. Identical or equivalent elements of the contact pins 2, 2 are provided with the same or equivalent reference signs, respectively.

(12) As opposed to the contact pin 2 as has been described above, the contact pin 2 which is illustrated in FIG. 4 has a contact tip 4 having a recess 9 or a depression or bore, respectively. When a support sleeve 6 of the contact pin 2 is being effused (the former being connected to the contact tip 4, as has been described above), the recess 9 is likewise effused with the support-core material such that the support core 8 reaches into the contact tip 4. Since the support-core material or the support core 8, respectively, is produced from a material having good (thermal) conductivity, such as copper, for example, heat dissipation from the contact tip 4 is improved by this design embodiment of the contact pin 2 such that the service life of the contact pin 2 is extended.

(13) FIGS. 2a-b show a schematic illustration of a pipe contact 10a according to a first design embodiment, before and after infiltration and post-machining.

(14) FIG. 2a shows the two precursor elements of the pipe contact 10a: an annular contact 12 having a receptacle opening 20 (for receiving the above-described contact pin 2), and a support pipe 14a. In an analogous manner to the description with reference to the contact pin 2, the annular contact 12 is produced from an arc resistant material and is disposed in a forward region of the pipe contact 10a in which arcs may arise during use. Respectively, the annular contact in the axial direction A has an extent/length which guarantees that arcs which arise during use are limited to the annular contact. In a manner which is likewise analogous to the support sleeve 6 of the contact pin 2, the support pipe 14a, in the case of the pipe contact 10a, is disposed in a region in which no arcs arise during use of the pipe contact 10a.

(15) In order for the pipe contact 10a to be produced, the annular contact 12 and the support pipe 14a are mutually aligned in an axial manner or disposed on one another so as to be axially aligned, respectively. The annular contact 12 and the support pipe 14a are provided as sintered bodies, for example, and subsequently are collectively infiltrated with copper, for example, in an infiltration process. The annular contact 12 and the pipe 14a are interconnected by the collective infiltration. The excess infiltration material is removed in a subsequent subtractive machining process, the pipe contact 10a being imparted the final shape thereof, as is schematically illustrated in FIG. 2b.

(16) In the design embodiment illustrated in FIGS. 2a-b, the support pipe 14a has a lesser wall thickness and the same internal diameter as the annular contact 12. An electrically conducting layer 16a remains on the external side of the support pipe 14a after infiltration and post-machining. As can be seen in FIG. 2b, the conducting layer 16a extends across the end edge of the support pipe 14a so that the pipe contact 10a may be reliably connected to a support (not illustrated), preferably by means of electron-beam welding. By way of infiltration, this layer 16a is connected in a stable manner to the annular contact 12 and the support pipe 14a, on account of which a pipe contact 10a which is extremely stable and has good electrical conductivity is provided. The support pipe 14a, which is exposed on the internal side, guarantees protection of the internal side of the pipe contact 10a from the influence of high temperatures and from hot gases, as has been described above with reference to the support sleeve 6 or the contact pin 2, respectively.

(17) FIGS. 3a-b show a schematic illustration of a pipe contact 10b according to a second design embodiment, before and after infiltration and post-machining. In as far as not stated to the contrary, the elements, functions, and materials used correspond to those as described above with reference to FIGS. 2a-b.

(18) As opposed to the first design embodiment, the support pipe 14b (at a lesser wall thickness) has the same external diameter as the annular contact 12. As can be seen in FIG. 2b, an electrically conducting layer 16b of the infiltration material is provided on account thereof on the internal side of the support pipe 14b after infiltration and subtractive machining. The support pipe 14a, which is exposed on the external side, guarantees protection of the external side of the pipe contact 10a from the influence of high temperatures and from hot gases, as has been described with reference to the support sleeve 6 or the contact pin 2, respectively.

(19) The materials which have been described above with reference to the contact tip 4, the support sleeve 6, or the core 8, respectively, may also be used for the annular contact 12, the support pipe 14a-b, or the electrical conductor 16a-b.

LIST OF REFERENCE SIGNS

(20) 2, 2 Contact pin/pin 4, 4 Contact tip 6 Support sleeve 8, 8 Support core 9 Recess 10a-b Pipe contact 12 Annular contact 14a-b Support pipe 16a-b Electrical conductor/infiltration material 20 Receptacle opening A Axis contact pin/axis pipe contact