Electric machine with a resistor for dissipating shaft voltages

Patent metadata

Field	Value
Publication number	US-9887606-B2
Application number	US-201514800452-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 15, 2014
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

An electric machine with at least one electrical resistor ( 24 ) for dissipating shaft voltages occurring at the rotor shaft ( 2 ) of a rotor ( 1 ), in which the electrical resistor ( 24 ) is enclosed in a contact ring ( 13 ) mounted on the rotor shaft ( 2 ) between contact surfaces ( 17, 23, 25, 28, 29 ) applied to the contact ring ( 13 ) on the outside, and in which the resistor ( 24 ) is electrically connected via the contact surfaces ( 17, 23, 25, 28, 29 ) to the rotor shaft ( 2 ) on one side and to the excitation winding ( 14 ) of the rotor ( 1 ) on the other side.

First claim

What is claimed is:

1. An electric machine comprising:
a rotor ( 1 ) having a rotor shaft ( 2 ) and an excitation winding ( 14 );
a slip-ring group ( 8 ) arranged on the rotor shaft ( 2 ), wherein the slip-ring group includes at least one slip ring ( 9 , 10 );
a contact ring ( 13 ) mounted on the rotor shaft ( 2 ) and having a first side and a second side, wherein the inner diameter of the contact ring ( 13 ) is larger than the outer diameter of the at least one slip ring ( 9 , 10 ) and the contact ring is pushed over the slip-ring group such that at least a portion of the at least one slip ring ( 9 , 10 ) is between the contact ring ( 13 ) and the end of the rotor shaft ( 2 ) relative to a longitudinal axis ( 20 ) of the rotor shaft ( 2 ); and
at least one electrical resistor ( 24 ) for dissipating shaft voltages occurring at the rotor shaft ( 2 ), wherein the electrical resistor ( 24 ) is enclosed in the contact ring ( 13 ) between contact surfaces ( 17 , 23 , 25 , 28 , 29 ) applied to the contact ring ( 13 ), and wherein the at least one electrical resistor ( 24 ) is electrically connected via the contact surfaces ( 17 , 23 , 25 , 28 , 29 ) to the rotor shaft ( 2 ) on the first side and to the excitation winding ( 14 ) on the second side.

2. The electric machine according to claim 1 , wherein the at least one slip ring ( 9 , 10 ) includes a first slip ring ( 10 ), characterized in that a first contact surface ( 17 , 29 ) is electrically conductively connected to the first slip ring ( 10 ), which is used as a negative slip ring, of the slip-ring group ( 8 ).

3. The electric machine according to claim 1 , characterized in that the contact ring ( 13 ) has at least one contact surface ( 23 , 28 ) which is electrically conductively connected to the rotor shaft ( 2 ).

4. The electric machine according to claim 1 , characterized in that the contact ring ( 13 ) has at least one contact surface ( 17 , 25 ) arranged on a side surface of the contact ring ( 13 ).

5. The electric machine according to claim 1 , characterized in that the contact ring ( 13 ) is disk-shaped and is arranged between the rotor winding ( 14 ) and a bearing ( 5 ), in which the rotor shaft ( 2 ) is mounted, on the rotor shaft ( 2 ).

6. The electric machine according to claim 5 , characterized in that the contact ring ( 13 ) has one axially oriented and one radially oriented contact surface ( 17 , 25 ; 23 , 28 , 29 ) for making contact with the enclosed electrical resistor ( 24 ), and in that the axially oriented contact surface ( 17 ) makes contact with a connecting lug ( 18 ) of a conductor routed to the rotor winding ( 14 ) and the radially oriented contact surface ( 23 , 28 ) is disposed around the rotor shaft ( 2 ).

7. The electric machine according to claim 1 , wherein the at least one slip ring includes a first slip ring ( 10 ), characterized in that the contact ring ( 13 ) has a first contact surface ( 28 ) on an inner ring surface pointing toward the rotor shaft ( 2 ), which first contact surface abuts the rotor shaft ( 2 ), and a second contact surface ( 29 ), which abuts at least one contact segment ( 30 ) of the first slip ring ( 10 ).

8. The electric machine according to claim 7 , characterized in that the first slip ring ( 10 ) is used as a negative slip ring.

9. The electric machine according to claim 7 , characterized in that the contact ring ( 13 ) is fastened by means of a press fit in the region of contact surfaces ( 23 , 28 , 29 ) pointing radially toward the rotor shaft ( 2 ).

10. The electric machine according to claim 1 , characterized in that the electrical resistor ( 24 ) has an ohmic resistance value of between 50 ohms and 10 kilohms.

11. The electric machine according to claim 1 , where in the contact ring ( 13 ) is formed with an electrically insulating material.

Assignees

• Bosch Gmbh Robert

Inventors

• Henger Martin
• Schroeder Bernd

Classifications

• H02K11/0094 Primary

  Structural association with other electrical or electronic devices · CPC title

• H02K7/08

  Structural association with bearings · CPC title

• H02K11/028

  Suppressors associated with the rotor · CPC title

• H02K13/02

  Connections between slip-rings and windings · CPC title

• H02K7/083

  radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence) · CPC title