SPOT WELDING APPARATUS FOR WELDING END CONDUCTORS IN CYLINDRICAL ELECTRICAL MACHINE ELEMENTS

• US 3,826,894 A
• Filed: 06/06/1973
• Issued: 07/30/1974
• Est. Priority Date: 06/06/1973
• Status: Expired due to Term

• Current Assignee: Raymond C. Melvin
• Original Assignee: Raymond C. Melvin
• Inventors: Melvin, Raymond C.
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US05/367,552
• Time in Patent Office: 419 Days
• Field of Search: 219/124,125,127,137,78,79,80,85,159 29/597,25CM 228/4,148
• US Class Current: 219/124.4
• CPC Class Codes: B23K 9/007 Spot arc welding
• CPC Class Codes: H01R 39/32 Connections of conductor to commutator segment
• CPC Class Codes: Y10T 29/49011 Commutator or slip ring assembly
• CPC Class Codes: Y10T 29/53157 Means to stake wire to commutator or armature

Abstract

A spot welding apparatus connects the coil end strips to commutating bars of an armature. A mixture has a rotating base supporting the armature at the end opposite the commutator. An adjustable top support locates a spot welding torch in proper alignment to the bar and with a spring loaded ground slidably engaging the same bar. The torch includes a two percent thoriated tungsten electrode having a tapered or pencilled tip terminating in a blunt or flat end. A high frequency, constant potential D.C. power supply is connected to the torch and maintains power instantly available to the electrode and ground under the control of a timer. A helium shield arc is created. A position sensor carried by the top support has a pair of conductive plungers axially aligned with and slidably engaging with the commutator bars to produce an on-off control as the plungers pass over an insulator between the bars. The sensor is connected to actuate the timer which operates the power supply to strike an arc for a predetermined time. A plurality of radially distributed spot welds are provided on each bar by a series of traverses or passes about the commutator. The ends of the coils of a wound rotor may also be similarly joined by spot welds automatically created by the method and apparatus.

Claims

1. In an apparatus for welding of coil lead means of an electric machine cylindrical element comprising a fixture means for supporting of an element with ends of the coil lead means in a predetermined planar relation, a non-consumable electrode arc spot welding torch means located adjacent the end of the element in spaced relation to said ends, means to establish relative movement between the element and the torch means, and control means to sequentially actuate said torch means in response to alignment of the torch means with the coil lead means to establish a welding arc between the torch and the aligned coil lead means.

2. The apparatus of claim 1 wherein said torch means includes a tungsten electrode, and means to supply a protective inert gas atmosphere about the end of the electrode.

3. The apparatus of claim 2 wherein said electrode is a two percent thoriated tungsten, and said gas is helium.

4. The apparatus of claim 1 wherein said electrode end is tapered to an essentially flat blunt end.

5. The apparatus of claim 1 wherein said torch means includes a tungsten electrode having a pencilled end terminating in a flat blunt end having a lateral diameter essentially within the range of 1/32 to 1/16 inches, and means to establish a helium protective atmosphere.

6. The apparatus of claim 1 having a sliding ground contact means for said torch means, and means to mount said contact means in sliding contact with the lead means.

7. The apparatus of claim 6 wherein said contact means is maintained in engagement with coil means being spot welded and immediately adjacent to the end.

8. The apparatus of claim 1 having a timing means connected to control the on-time of said torch means to create a corresponding arc, means to continuously rotate said cylindrical element, and sensing means responsive to alignment with each of said end connections to actuate said timing means and energize said torch means.

9. The apparatus of claim 8 wherein said timing means included a control relay, a power supply for operating of said control relay and having said sensing elements connected in series with said power supply and said control relay.

10. The apparatus of claim 8 wherein said torch means includes a 2 per cent thoriated tungsten electrode terminating in a blunt, essentially flat end of diameter between 1/32 and 1/16 inches and having means to supply a protecting helium gas about the end and adjacent arc, said fixture includes a rotating base support unit having means to support the element projecting axially upwardly to locate said connection legs in a common horizontal plane, a top support unit including horizontal and vertical guide means engaging the top end and adjacent side portion of the element, said guide means being adjuStably mounted to accommodate varying size elements, means connected to said top support unit for adjustably mounting of said torch means relative to said coplanar end connection.

11. The apparatus of claim 10 including a ground contact located in alignment with said torch means and slideably engaging the periphery of the coil lead means immediately adjacent to the torch means.

12. The apparatus of claim 8 including a DC welding power supply having a constant output instantly applied to the torch in response to activation of the timing means and maintained for a selected time.

13. An apparatus for welding of a plurality of circumferentially spaced coil connections in an essentially common radial plane, comprising a torch means mounted to traverse said radial plane, said torch means including a two percent thoriated tungsten electrode and gas shielding means, a constant potential welding supply connected to energize said electrode and having a source of helium shielding gas, said welding supply being continuously energized to establish a welding potential at an output means, a timing means operable to initially complete the connection of the output means to the torch means, and conductive sensing means mounted to traverse said connecting means and slideably engaging said connection means to produce control signals in response to the sequential alignment with each coil connection, and means connecting the sensing means to actuate the timing means.

14. The apparatus of claim 13 wherein said welding supply is a high frequency direct current supply, and said timing means includes a power supply separate from said welding supply.

15. In an apparatus for welding of coil lead means to copper commutating bars of a dynamoelectric machine element, comprising a fixture means for supporting of a rotor element, a non-consumable electrode arc spot welding torch means, means to establish relative movement between the rotor element and the torch means, and control means to sequentially actuate said torch means in response to alignment of the torch means with a commutating bar to establish a welding arc between the torch and the aligned commutating bar.

16. The apparatus of claim 15 wherein said commutating bars are individual, L-shaped members having a short radial connection leg aligned with an axially extended rotor conductor, said leg having the rotor conductors exposed on the axial end face of the connecting legs, a support unit including horizontal and vertical guide means engaging the end and adjacent side portion of the L-shaped members, means connected to said support unit for adjustably mounting of said torch means relative to said coplanar connection legs, a ground contact means resiliently engaging the outer circumference of the connection leg, and a pair of sensing elements mounted to resiliently engage a single commutator bar and having a width no greater than the interbar insulator to open the circuit therebetween as each interbar insulator passes the sensing elements, and a timing means having an input means connected to said sensing means and connected to control the on-time of said torch to create a corresponding arc.

17. The apparatus of claim 16 wherein said torch includes a tungsten electrode and means to supply a protective helium gas atmosphere about the end of the electrode.

18. The apparatus of claim 16 wherein said torch means has an electrode, said electrode end being tapered to an essentially flat blunt end.

19. The apparatus of claim 16 wherein said torch includes a tungsten electrode having a pencilled end terminating in a flat blunt end having a lateral diameter essentially within the range of 1/32 to 1/16 inches.

20. The apparatus of claim 16 wherein said timing means includes a control relay, a power supply for operating of said control relay and having said sensing elements connected in series with said power supply and said control relay.

21. The apparatus of claim 16 wherein said sensing elements are spring-loaded conductive plungers mounted in vertical alignment, attachment means for said plungers connected to said support means and locating said plungers in alignment with a commutating bar in synchronism with location of the torch means with a commutating bar.

22. The apparatus of claim 16 wherein said commutating bars have split connection legs and said lead means are strips extended within said bars and exposed in the outer surface of said connection portions, and said spot welds being formed on each outer surface of each of said bars integrally connecting each rotor conductor to the corresponding commutating bars.

23. The method of spot welding of the end conductors of the coils in a slotted cylindrical rotor to a commutator having circumferentially spaced commutator bars separated by insulating members, comprising continuously moving a torch means relative to the commutating bars in spaced welding relation to each of said bars, simultaneously moving a conductive sensing means around said commutator in operative sensing relation to said bars, and activating said torch means for a predetermined time in response to the sensing of each commutator bar.

24. The method of claim 23 including the step of continuously energizing a welding supply to establish a welding potential at an output means and activating said torch means by completing a connection of the supply to the torch means.

25. The method of claim 23 including the steps of establishing a plurality of radially spaced welded connections to each of said commutator bars by sequentially circumferentially traversing of said bars at least twice and establishing a selected spot weld connection during each traverse.