HEAVY-CURRENT TRANSFORMER HAVING A MULTI-POINT CONTACTING, TRANSFORMER ELEMENT, CONTACT PLATE AND SECONDARY WINDING, AND METHOD FOR PRODUCING SUCH A HEAVY-CURRENT TRANSFORMER

• US 20140313679A1
• Filed: 10/31/2012
• Published: 10/23/2014
• Est. Priority Date: 10/31/2011
• Status: Active Grant

• Current Assignee: Fronius International GmbH (G&K Privatstiftung)
• Original Assignee: Fronius International GmbH (G&K Privatstiftung)
• Inventors: Artelsmair, Bernhard, Schultschik, Christoph, Neuboeck, Johannes, Wolfsgruber, Stefan
• Granted Patent: US 10,141,106 B2
• Time in Patent Office: Days
• US Class Current: 361/748
• CPC Class Codes: B23K 11/241 Electric supplies B23K11/248 takes precedence
• CPC Class Codes: B23K 11/314 Spot welding guns, e.g. mounted on robots
• CPC Class Codes: H01F 27/08 Cooling heat-transfer elements F28F; Ventilating structural details of casings H01F27/02
• CPC Class Codes: H01F 27/16 Water cooling
• CPC Class Codes: H01F 27/20 Cooling by special gases or non-ambient air
• CPC Class Codes: H01F 27/29 Terminals; Tapping arrangements for signal inductances
• CPC Class Codes: H01F 38/085 Welding transformers
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: H01F 41/0246 Manufacturing of magnetic circuits by moulding or by pressing powder magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36
• CPC Class Codes: H01F 41/10 Connecting leads to windings making electric connections in general H01R43/00
• CPC Class Codes: H05K 1/18 Printed circuits structurally associated with non-printed electric components H05K1/0201, H05K1/023, H05K1/0243, and H05K1/16 take precedence
• CPC Class Codes: H05K 2201/1003 Non-printed inductor
• CPC Class Codes: H05K 3/34 by soldering
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 by assembling coil and core
• CPC Class Codes: Y10T 29/49144 by metal fusion

Abstract

The invention relates to a heavy-current transformer (12), in particular for a power source (10) in order to provide a welding current of a resistance welding device (1), with at least one primary winding (13) and at least one secondary winding (14) with center tapping, and to a transformer element, a contact plate (29) and a secondary winding (14) for such a heavy-current transformer (12) as well as a method for the manufacturing thereof. For reduction of losses and improvement of efficiency, at least four contacts (20, 21, 22, 23) are provided to form a multi-point contacting, said contacts (20, 21, 22, 23) being formed by four contact faces within which the at least one primary winding (13) and the at least one secondary winding (14) are arranged in a series/parallel connection.

Claims

1-50. -50. (canceled)

51. A heavy-current transformer (12), in particular for a power source (10) in order to provide a welding current of a resistance welding device (1), with at least one primary winding (13) and at least one secondary winding (14) with center tapping, wherein at least four contacts (20, 21, 22, 23) are provided to form a multi-point contacting, whereby the welding current is at least halved and the contact losses are thus reduced, said contacts (20, 21, 22, 23) being formed by four contact faces within which the at least one primary winding (13) and the at least one secondary winding (14) are arranged in a series/parallel connection.

52. The heavy-current transformer (12) according to claim 51, wherein a plurality of, preferably at least 10, primary windings (13) connected in series, and a plurality of, preferably at least 10, secondary windings (14) with center tapping connected in parallel are provided.

53. The heavy-current transformer (12) according to claim 51, wherein an I-beam (25) of electrically conductive material is provided, in the recesses (25a) of which at least one respective ring core (15) is arranged, wherein one respective connection of each secondary winding (14) is directly contacted with one inner surface and the contact plate (29) of the I-beam (25), and wherein the outer surfaces (28) of the I-beam (25) form two contacts (20, 21), and wherein the center tapping of the at least one secondary winding (14) of the heavy-current transformer (12) is connected with the I-beam (25) without lines.

54. The heavy-current transformer (12) according to claim 53, wherein the at least one primary winding (13) is arranged to run through the at least one ring core (15) and around the central web of the I-beam (25).

55. The heavy-current transformer (12) according to claim 53, wherein respective contact plates (29) are located above the recesses (25a) of the I-beam (25) and the secondary winding (14) arranged therein, said contact plates (29) being of electrically conductive material and connected with the respectively other connections of each secondary winding (14) via a synchronous rectifier (16) and an actuation circuit (17), wherein the outer surfaces of the contact plates (29) form the two additional contacts (22, 23) of the power source (10).

56. The heavy-current transformer (12) according to claim 51, wherein one secondary winding (14) with center tapping is each formed by two metal sheets (44, 45) insulated from each other and being of electrically conductive material and having a substantially S-shaped mirror-inverted course around the cross-section of a ring core (15) and through the ring core (15), wherein the exterior surfaces (47) of the metal sheets (44, 45) form contacts.

57. The heavy-current transformer (12) according to claim 53, wherein the I-beam (25) and the contact plates (29) form a cube or ashlar-shaped unit, wherein an electrical insulation is arranged between the I-beam (25) and the contact plates (29), wherein cover plates (31) are arranged at the front faces of the I-beam (25), and wherein the cover plates (31) are formed of electrically conductive material and are adapted to be screwed to the contact plates (29), so that the contact plates (29) are connected electrically.

58. The heavy-current transformer (12) according to claim 53, wherein the I-beam (25) and/or the contact plates (29) and/or the cover plates (31) and/or the metal sheets (44, 45) for forming the secondary winding (14) are formed of copper or a copper alloy, preferably with a silver coating.

59. The heavy-current transformer (12) according to claim 51, wherein at the first secondary winding (14) of each side of the I-beam (25) a current transducer (18) each is arranged for measuring the current through this secondary winding (14).

60. The heavy-current transformer (12) according to claim 53, wherein channels (39) for feeding a cooling fluid are arranged in the I-beam (25) and the contact plates (29), wherein two inlets (32) for feeding the cooling fluid and one outlet (33) for discharging the cooling fluid are arranged at an outer surface of the I-beam (25), wherein the cooling channels (39) are arranged to extend from each inlet (32) to the contact plates (29) and via the I-beam (25) to the outlet (33).

61. The heavy-current transformer (12) according to claim 51, wherein a synchronous rectifier (16) with circuit elements (24) and a circuit (17) for actuating the circuit elements (24) of the synchronous rectifier (16) are connected with the at least one secondary winding (14).

62. The heavy-current transformer (12) according to claim 61, wherein the actuation circuit (17) is designed to activate the circuit elements (24) of the synchronous rectifier (16) at a preset point in time prior to reaching zero crossing of the current in the secondary winding (14).

63. The heavy-current transformer (12) according to claim 61, wherein the circuit elements (24) of the synchronous rectifier (16) are connected without lines with the at least one secondary winding (14).

64. The heavy-current transformer (12) according to claim 62, wherein the actuation circuit (17) and the synchronous rectifier (16) are arranged on at least one circuit board (35) which is arranged on the inner surface of at least one contact plate (29), and wherein each circuit board (35) of the synchronous rectifier (16) and of the actuation circuit (17) comprises openings (37) above which the circuit elements (24) are arranged, and wherein the inner surface of the contact plates (29), in the places of the openings (37) in the circuit board (35) of the synchronous rectifier (16), comprises protrusions (36), in particular pinnacle-shaped protrusions, so that the circuit elements (24) can be contacted without lines via the protrusions (36) protruding into the openings (37) on the circuit board (35) on the inner surface of the contact plates (29).

65. A method for manufacturing a heavy-current transformer (12) comprising at least one primary winding (13) and at least one secondary winding (14) with surfaces (47) for contacting, wherein at first inner surfaces (47) of the at least one secondary winding (14) are connected with an I-beam (25) of electrically conductive material of the heavy-current transformer (12) with a first soldering material at a first, higher melting temperature (T_s1), and subsequently at least one contact plate (29) of electrically conductive material is soldered with exterior surfaces (47) of the at least one secondary winding (14) with a second soldering material at a second melting temperature (T_S2) that is lower as compared to the first melting temperature (T_S1).

66. The method according to claim 65, wherein a circuit board (35) is connected with the at least one contact plate (29) with the first soldering material at the first, higher melting temperature (T_S1).

67. The method according to claim 66, wherein after connecting the at least one contact plate (29) with the circuit board (35), circuit elements (24) are connected with the circuit board (35) and/or the contact plate (29), in particular with protrusions (36) on the contact plate (29), by using the first soldering material at the first, higher melting temperature (T_S1).

68. The method according to claim 67, wherein the circuit elements (24), in particular the connections or the housings of the circuit elements (24), are connected with the surfaces (47) of the at least one secondary winding (14) with the second soldering material at the second, lower melting temperature (T_S2).

69. The method according to claim 65, wherein a first soldering material at a first melting temperature between 220°

C. and 300°

C., in particular 260°

C., and a second soldering material at a second melting temperature between 120°

C. and 220°

C., in particular 180°

C., is used.