ELECTRIC MOTOR HAVING COMPACT BUSBAR UNIT

Abstract

An electric motor includes three busbars in contact at end surfaces thereof and including ring-segment-shaped base portions to provide electrical connection of the busbars. The base portion of a first busbar is in a first plane and the base portion of a second busbar is in a second plane. The base portion of the first busbar extends clockwise from the terminal of the first busbar and the base portion of the second busbar extends counterclockwise from the terminal of the second busbar. Terminals of the first and second busbars are spaced apart with the terminal of the third busbar between the first and third terminals. The third busbar includes a first region extending clockwise from its terminal and lying in the second plane and a second region extending counterclockwise from its terminal and lying in the first plane.

Claims

1-10. (canceled)

11. An electric motor comprising: a rotor rotatably supported about an axis of rotation; and a stator externally surrounding the rotor and including a stator core and coils wound on the stator core; wherein the windings include a winding wire including winding wire end portions; the winding wire end portions are electrically contacted with three bus bars at ends thereof to define phases; the three bus bars each include a power source connection terminal to electrically contact the bus bar with a power source and a ring segment-shaped base portion to electrically connect the bus bars with the winding wire end portions; the base portion of a first busbar of the three bus bars is in a first plane perpendicular or substantially perpendicular to the axis of rotation; the base portion of the second busbar is in a second plane perpendicular to the axis of rotation and spaced apart from the first plane; the base portion of the first busbar extends clockwise from the power source connection terminal of the first busbar and the base portion of a second busbar of the three busbars extends counterclockwise from the power source connection terminal of the second busbar; the power source connection terminals of the first busbar and the second busbar are spaced apart from each other; the power source connection terminal of a third busbar of the three busbars is circumferentially located between the power source connection terminals of the first busbar and the third busbar; the third busbar includes a first portion extending clockwise from its power source connection terminal, which lies in the second plane, and a second portion which extends counterclockwise from its power source connection terminal and lies in the first plane.

12. The electric motor according to claim 11, wherein the base portions of the first busbar, the second busbar, and the third busbar have a same radius.

13. The electric motor according to claim 11, wherein the busbars are at least partially accommodated in a busbar holder which is attached to a top of the stator.

14. The electric motor according to claim 11, wherein the base portion of the third busbar is completely or substantially completely covered by the first busbar and the second busbar in a plan view.

15. The electric motor according to claim 11, wherein the first portion and the second portion of the third busbar each extend over about 105°.

16. The electric motor according to claim 11, wherein the first busbar and the second busbar overlap at ends thereof remote from the power source connection terminal in a plan view.

17. The electric motor according to claim 11, wherein the first busbar and the second busbar each include a base portion extending through approximately 210°.

18. The electric motor according to claim 11, wherein the third bus bar includes a shoulder in the base portion extending in an axial direction that is parallel or substantially parallel with the axis of rotation.

19. The electric motor according to claim 18, wherein the power source connection terminal of the first busbar is located in the first plane, the power source connection terminal of the second busbar is located in the second plane, and the power source connection terminal of the third busbar is located in the axial direction between the first plane and the second plane.

20. The electric motor according to claim 11, wherein a distance between the first plane and the second plane provides electrical insulation between the three busbars.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Example embodiments of the present disclosure are explained in more detail below with reference to the drawings.

[0027] FIG. 1 shows a schematic representation of a stator according to an example embodiment of the present invention in a plan view.

[0028] FIG. 2 shows a schematic representation of the stator of FIG. 1 with busbars.

[0029] FIG. 3 shows a schematic representation of the power source connections of the three busbars shown in FIG. 2.

[0030] FIG. 4 shows a longitudinal section through a schematically shown electric motor with stator and busbars according to an example embodiment of the present invention.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a stator 1 of an electric motor. The stator 1 of the electric motor consists of an iron core and has three phase windings 3 constructed from a plurality of coils 2 on the poles to form a four-pole motor, with the coils 2 wound on the respective poles. Stator teeth extend inwardly from the iron core, leaving a cylindrical inner region within which the rotor of the motor, not shown, rotates during operation. The three phases U,V,W are formed by interconnected pairs of windings 4 so that two parallel current paths are formed in a delta connection. A first coil of each winding pair 4 is formed by winding a tooth counterclockwise. This is followed without interruption by winding a clockwise second tooth of the winding pair 4, which is immediately adjacent to the first tooth. The winding wire ends 7 of the winding pairs 4 are electrically contacted towards the center of the stator. All six winding pairs 4 are wound according to the same scheme. The necessary reversal of the magnetic pole within the winding pair 4 is achieved by an inverted electrical connection and a reversal of the direction of the current flow. The wire ends to be connected to each other are thus at an angle of approximately 150°. The respective contacts of one phase are distributed over a range of approximately 210°.

[0032] FIG. 2 shows a schematic top view of a busbar unit 8 of the stator 1 shown in FIG. 1. The busbar unit 8 comprises a busbar holder not shown and three busbars 9, 10, 11 mounted on the busbar holder. The busbars 9,10,11 are made of an electrically conductive material, preferably metal, in particular copper. The busbar holder consists at least partly or completely of an electrically insulating material, so that short circuits between the busbars 9,10,11 can be effectively prevented. The busbar holder is preferably produced by injection molding and extends over part of the busbars 9,10,11. In this way, a solid and well-defined physical connection between the busbar holder and the busbars 9,10,11 can be provided. The busbar holder is adapted to be positioned on an axial side of the stator (top side).

[0033] The busbar unit 8 is set up to electrically contact the coils 2 of stator 1 by means of busbars 9,10,11. The coils 2 are grouped in the three phase groups U, V, W. Four winding wire end sections 7 each contact a busbar. The busbar of one phase extends over a range of 210°. Each of the busbars 3,4,5 has a power source connection terminal 12,13,14 arranged to electrically connect the busbar to a line source.

[0034] The busbars 9,10,11 are each arranged with a base portion 9′,10′,11′ along the circumference with a fixed radius. The base portions 9′,10′,11′ are shaped like ring segments.

[0035] In the illustration of FIG. 2, the busbars appear to be on different radii to show the arrangement of the busbars on different planes. This arrangement of the busbars is described below.

[0036] A first busbar 9 extends over a range of approximately 210° with its base portion 9′ along the circumference. This first busbar lies in a first plane E1. It has the power source connection terminal 12 at one end of the base portion 9′. Starting from the power source connection terminal 12, the base portion 9′ extends in a clockwise direction. A second bus bar 10 also extends with its base portion 10′ over a range of about 210° along the circumference with the same radius as the first bus bar. The second busbar lies in a second plane E2. It has the power source connection 13 at one end of the base portion 10′. Starting from the power source connection port 13, the base portion 10′ extends counterclockwise. In a plan view, the two busbars 9,10 are arranged overlapping at their ends remote from the power source. The two planes E1 and E2 are selected so that the ends overlap in the axial direction but do not touch and are electrically insulated from each other. The two busbars are spaced apart by a in the axial direction.

[0037] The third busbar 11 has a power source connection terminal 14 located circumferentially between the terminals 12,13 of the first and second busbars 9,10. All three terminals 12,13,14 are in close proximity to each other. Starting from the third power source connection 14, the third busbar 11 extends in a first area 11″ towards the first busbar 9 on the second level E2 and in a second area 11′″ towards the second busbar 10 on the first level E1. Thus, in a plan view, the third busbar 11 is arranged in the first area 11″ overlapping with the first busbar 9 and in the second area 11′″ overlapping with the second busbar 10. Each of the areas 11″, 11′″ extends in the manner of a ring segment over approximately 105°.

[0038] FIGS. 3 and 4 show the arrangement of the busbars in the axial direction 100. As shown in FIG. 3, the third busbar 11 changes plane halfway along the base portion 11′. The base portion of the third busbar is thus divided between the two sections 11″,11′″. Thus, the third bus bar 11 has a step 15 in the base portion 11′. The power source connection terminal 12 of the first busbar 9 is located in the first plane E1, the power source connection terminal 13 of the second busbar 10 is located in the second plane E2, and the power source connection terminal 14 of the third busbar 11 is located between the two planes E1,E2 in the axial direction. The three busbars 9,10,11 are distributed over only two planes E1,E2. The axial extent of the stator pack and thus also the overall height of the electric motor in the axial direction are therefore kept to a minimum in order to save installation space.

[0039] FIG. 4 schematically shows an electric motor 16 with stator 1, which carries the busbar unit 8 on its end face. The busbars 10,11 lie in two different planes E1,E2. The third busbar 11 is in contact with a winding wire end section 7 of the associated coil.

[0040] While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.