ELECTRIC MACHINE

Abstract

An electric machine including armature equipped with armature slots for accommodating armature coils, a commutator equipped with commutator segments, and a first and second hammer brush that each rest against the commutator in sliding fashion by means of a spring lever, in which at least one armature coil is comprised of two partial coils that are situated symmetrically to each other in relation to the rotation axis of the armature and the partial coils are connected to two adjacent commutator segments of the commutator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in detail below, in conjunction with the accompanying drawings, in which:

FIG. 1 a shows an electric machine with two hammer brushes when new,

FIG. 1 b shows an electric machine with two hammer brushes at the end of their service life,

FIG. 2 shows a first embodiment of armature coils with two symmetrical partial coils connected in series,

FIG. 3 shows a second embodiment of armature coils with two symmetrical partial coils connected in parallel, and

FIG. 4 shows an arrangement of three hammer brushes that are positioned against a commutator, offset from each other in the rotation direction.

Claims

1. In an electric machine including an armature equipped with armature slots for accommodating armature coils, a commutator equipped with commutator segments, and a first and second hammer brush that each rest against the commutator in sliding fashion by means of a spring lever, the improvement wherein at least one armature coil is comprised of two partial coils that are situated symmetrically to each other in relation to the rotation axis of the armature and the partial coils are connected to two adjacent commutator segments of the commutator.

2. The electric machine according to claim 1, wherein the two partial coils are situated essentially geometrically parallel to each other.

3. The electric machine according to claim 1, wherein the two partial coils have the same number of windings.

4. The electric machine according to claim 2, wherein the two partial coils have the same number of windings.

5. The electric machine according to claim 1, wherein the two partial coils are wound in opposite winding directions.

6. The electric machine according to claim 2, wherein the two partial coils are wound in opposite winding directions.

7. The electric machine according to claim 3, wherein the two partial coils are wound in opposite winding directions.

8. The electric machine according to claim 1, wherein the two partial coils are electrically connected in series.

9. The electric machine according to claim 2, wherein the two partial coils are electrically connected in series.

10. The electric machine according to claim 3, wherein the two partial coils are electrically connected in series.

11. The electric machine according to claim 5, wherein the two partial coils are electrically connected in series.

12. The electric machine according to claim 8, wherein the two series-connected partial coils have two ends that are connected to adjacent commutator segments.

13. The electric machine according to claim 9, wherein the two series-connected partial coils have two ends that are connected to adjacent commutator segments.

14. The electric machine according to claim 10, wherein the two series-connected partial coils have two ends that are connected to adjacent commutator segments.

15. The electric machine according to claim 11, wherein the two series-connected partial coils have two ends that are connected to adjacent commutator segments.

16. The electric machine according to claim 1, wherein the two partial coils are electrically connected in parallel.

17. The electric machine according to claim 16, wherein each of the two parallel-connected partial coils has two ends and the ends of each respective partial coil are connected to adjacent commutator segments.

18. The electric machine according to claim 1, further comprising a third hammer brush, the first and second hammer brushes being situated opposite each other and cooperating in a first speed stage and the third hammer brush being situated radially between the first and second hammer brush and cooperating with the second hammer brush in a second speed stage.

19. The electric machine according to claim 2, further comprising a third hammer brush, the first and second hammer brushes being situated opposite each other and cooperating in a first speed stage and the third hammer brush being situated radially between the first and second hammer brush and cooperating with the second hammer brush in a second speed stage.

20. The electric machine according to claim 3, further comprising a third hammer brush, the first and second hammer brushes being situated opposite each other and cooperating in a first speed stage and the third hammer brush being situated radially between the first and second hammer brush and cooperating with the second hammer brush in a second speed stage.