CN113273060A

CN113273060A - Pump equipped with an electric motor with a compact busbar unit

Info

Publication number: CN113273060A
Application number: CN201980069075.6A
Authority: CN
Inventors: K·塔提格塔
Original assignee: Nidec GPM GmbH
Current assignee: Nidec GPM GmbH
Priority date: 2018-10-26
Filing date: 2019-09-10
Publication date: 2021-08-17
Also published as: DE102018126777A1; WO2020083559A1

Abstract

The invention relates to a pump (16) equipped with an electric machine (17) having a rotor which can be rotatably mounted about a rotational axis (100) and having a stator (6) which surrounds the rotor on the outside and has a stator core (7) and a winding (8) which is arranged on the stator core (7), wherein the winding (8) is formed by a winding wire having a winding wire end (12), and wherein the winding wire end (12) is electrically connected on the end side to at least three busbars (3, 4, 5), wherein the at least three busbars (3, 4, 5) have a coil connection end (14), a power source connection end (13) and a ring segment-type base body segment (30, 40, 50), wherein the base segment (30, 40, 50) connects the coil connection end (14) to the power source connection end (13), and wherein the first busbar (3) and the second busbar (5) are spaced apart from one another in the circumferential direction about the rotational axis (100) and are base-spaced apart from one another The body sections (30, 50) are arranged in one and the same plane perpendicular to the axis of rotation (100), and the third busbar (4) is arranged between the first busbar (3) and the second busbar (5) in a circumferential direction around the axis of rotation, and the base section (40) of the third busbar is arranged in a plane perpendicular to the axis of rotation between the end side of the stator and the plane defined by the base sections (30, 50) of the first and second busbars.

Description

Pump equipped with an electric motor with a compact busbar unit

The invention relates to a pump having the features of the preamble of claim 1.

Pumps are used in motor vehicles, for example as coolant pumps. The pump usually has a brushless dc motor, which is also referred to as an internal rotor motor. The dc motor includes a rotor that is coupled to the motor shaft and rotatably mounted in the housing. The rotor is provided with permanent magnets. The stator is arranged around the motor with a number of windings on the core of the stator. Under appropriate control, the windings generate magnetic fields to drive the rotor to rotate. The winding is usually a three-phase winding and accordingly three electrical terminals are provided, by means of which the winding can be connected to a control unit (ECU). At low power, the busbars may be designed as strip-shaped conductive foils. At high power, as assumed here, the winding connection lines are connected by busbars made of copper plates.

For the geometric description of the motor, it is assumed, on the one hand, that the axis of rotation of the motor is the central axis and the axis of symmetry. The stator is disposed concentrically with the axis of rotation and the rotor. The axis of rotation defines simultaneously an axial direction along which the thickness of the stator stack and the axial length of the electrical machine are determined. Further, the radial direction and the circumferential direction are also relative to the central axis, the radial direction representing the distance to the central axis, and the circumferential direction representing tangency with respect to a particular radius disposed in the radial direction. The connection side of the stator, i.e., the connection side of the winding wire and the bus bar assembly, is described as the top of the stator.

Especially when the electric machine is applied in a coolant pump in a motor vehicle, for the electric machine in question also dimensions are essential in addition to performance data and weight. The installation space in motor vehicles is usually limited and must comply with the specifications given by the motor vehicle manufacturer. Therefore, the design of the electrical machine imposes a constant requirement, for example, that the direction along the central axis does not exceed a certain axial length. In this respect, the performance data required of the electrical machine essentially determine the axial length of the stator lamination stack and the rotor together with the electromagnets arranged thereon. The bus bar units required for switching the winding connections of the stator also contribute to the axial length.

For example, JP 2014-158421A discloses an electric machine in which a busbar unit having three conductive rails is arranged in the axial direction above a stator lamination stack and connected with winding connection lines. The busbar unit includes a plurality of busbars arranged in a partial circle concentric with the central axis. The plurality of busbars are arranged in a stacked manner with each other in the axial direction. Since the plurality of busbars and the electrical insulation required between these busbars are arranged above the winding stack on the stator, they contribute to the axial length of the stator stack.

The object of the invention is to design a pump equipped with an electric motor such that the axial extension of the stator lamination stack is reduced and thus the overall height of the electric motor in the axial direction is reduced.

The above object is achieved by a pump having the features of claim 1.

According to this, a pump equipped with an electric motor is provided, which has a rotor and a stator surrounding the rotor on the outside, the rotor being rotatably mounted about a rotational axis, the stator having a stator core and a coil wound on the stator core, the winding being formed by a winding wire having a winding wire end, and the winding wire end being electrically connected on the end side to at least three busbars having a coil connection end element, a power source connection end element and a base section in the form of a ring segment, and the base section connecting the coil connection end element with the power source connection end element. The first and second busbars are spaced from each other in a circumferential direction around the axis of rotation, and the base sections are arranged in one and the same plane perpendicular to the axis of rotation, and a third busbar is arranged between the first and second busbars in a circumferential direction around the axis of rotation, and the base section of the third busbar is arranged in a plane perpendicular to the axis of rotation between an end side of the stator and a plane defined by the base sections of the first and second busbars. Preferably, the busbars are oriented parallel to one another. Preferably, each busbar extends perpendicularly to the axis of rotation. Since the base body sections are not all arranged at one axial level, the orientation of the bus bars can be selected, which allows a smaller axial extension, thus making the pump more compact.

In a preferred embodiment, the base body section of the third busbar is arranged outside the coil in a radial direction with respect to the axis of rotation, and the base body sections of the first and second busbars at least partially cover the coil in the radial direction. Therefore, the third bus bar can be disposed in a free space between the stator core outside the coil and the top of the stator, thereby saving an installation space.

Preferably, the base body section of the first busbar and the base body section of the second busbar have the same radius and are preferably arranged in a busbar holder along a common circumference. Preferably, the bus bar support is fixed to a top of the stator.

In a preferred embodiment, in the radial direction, the coil is surrounded on the outside by a positioning means on which the busbar holder is held. Advantageously, the base body section of the third busbar is arranged outside the positioning means in a radial direction with respect to the axis of rotation.

Preferably, the coil connection end element has a substantially U-shaped or V-shaped form and extends in a plane perpendicular to the axis of rotation, so that the coil connection end element can preferably enclose the winding wire ends extending substantially parallel to the direction of rotation.

The busbar has a bent portion away from the top of the stator, and the coil connection end element is disposed at an end of the bent portion.

In an advantageous embodiment, the distance in the radial direction between the base body section of the third busbar and the base body sections of the first and second busbars is selected to be of sufficient size that the coil connection end element can be accommodated between the base body section of the third busbar and the base body sections of the first and second busbars, respectively.

Preferably, the busbars are oriented relative to each other such that the third busbar is partially covered by the first and second busbars.

Preferably, the bus bar has a bent portion toward a top of the stator, the power source connection end element is provided at an end of the bent portion, and a short side of the power source connection end element extends parallel to the rotation axis.

In a preferred embodiment, the pump is used for an electric coolant pump, in particular a dry rotor pump, for a motor vehicle.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Identical or functionally identical components are denoted by the same reference numerals in the figures. Wherein:

FIG. 1 is a top perspective view of a busbar unit;

FIG. 2 is a bottom perspective view of the busbar unit;

fig. 3 shows a perspective view of a stator with a busbar unit;

FIG. 4 shows a perspective view of a buss bar; and

fig. 5 shows a longitudinal section of the coolant pump.

Fig. 1 and 2 show a top view and a bottom view of a busbar unit 1 for a stator of an electric machine. The busbar unit 1 includes a busbar holder 2 and three

busbars

3, 4, 5 mounted on the busbar holder 2. The

busbars

3, 4, 5 are made of an electrically conductive material, preferably a metal, in particular copper. The busbar holder 2 is at least partially or completely made of an electrically insulating material, so that short circuits between the

busbars

3, 4, 5 can be effectively prevented. The busbar holder 2 is preferably produced by injection molding and extends over a portion of the

busbars

3, 4, 5. In this way, a firm and clearly defined physical connection between the busbar holder 2 and the

busbars

3, 4, 5 can be provided. The busbar holder 2 is provided for positioning on one axial side (top) of the stator.

Fig. 3 shows the stator 6 mounted with the bus bar support 2 of a substantially annular shape. The stator 6 has a stator core 7, the stator core 7 extending coaxially with the longitudinal axis 100 and having a plurality of stator core segments, not shown, each wound with a coil 8 therearound. The coil 8 is only schematically shown. Viewed in the radial direction, the outside of the coil 8 is surrounded by a positioning mechanism 9. The positioning means 9 may be made of an electrically insulating material to avoid short-circuits between the winding wires of different phases. The stator core segments are arranged in sequence in the circumferential direction of the stator 6. Each stator core segment may be at least partially made of a ferromagnetic material, for example ferromagnetic steel. The stator 6 is fixedly mounted inside the housing of the electrical machine and is arranged to generate a time-varying magnetic field by means of the coil 8. A not shown magnetized rotor is thus mounted in the central opening 10 of the stator 6. The magnetized rotor is arranged to rotate by interaction with a time-varying magnetic field generated by the coil 6. The busbar unit 1 is arranged to be electrically connected to the coils 8 of the stator by the

busbars

3, 4, 5. The busbar unit 1 has arms 11 distributed uniformly at intervals in the circumferential direction, the ends of which are bent and which are in contact with the positioning means 9 in order to be fixed on the stator 6, and are preferably snap-fitted. The coil 8 is divided into three phase groups U, V, W. The coils of each phase group U, V, W are formed by winding wire that is wound around the corresponding stator core segment of stator core 7, and the winding wire may be connected to a power source through winding wire end 12.

Fig. 4 shows three

busbars

3, 4, 5. The

busbars

3, 4, 5 each have a power source connection end element 13 adapted to be electrically connected to a power source and two coil connection end elements 14 adapted to be electrically connected to the coils of the stator 8.

The coil connecting end element 14 has a substantially U-or V-shape and extends in a plane perpendicular to the longitudinal axis 100. In other words, the coil connecting end elements 14 have a U-shaped or V-shaped contour in a transverse sectional view relative to the longitudinal axis 100 and each enclose a winding wire end 12 running approximately parallel to the longitudinal direction. In this connection, all openings of the coil connection end elements 14 for the introduction of the winding wire ends 12 are directed in the circumferential direction, except for the openings of the coil connection end elements 14' which are oriented in the opposite direction. The axial height h of the coil connection end element can thus be reduced in comparison with the prior art, which discloses that the coil connection end element is joined from above to the radially extending winding wire ends. Preferably, the coil connection end element 14 is designed as a crimping element which is crimped around the winding wire end 12. In this way, the winding wire end 12 can be electrically connected to the

busbars

3, 4, 5 simply by mechanical deformation of the respective coil connection end element 14. The busbar holder 2 has a stator surface 15 shown in fig. 1 and 2, which engages with the stator (top). The power source connection end member 13 protrudes in the radial direction from the stator surface of the busbar holder 15. In this way the axial extension of the stator is not significantly increased by the power source connection end element 13. To form the power source connecting end member 13, each bus bar preferably has a bent portion toward the top of the stator. The rectangular power source connection end element has a short side, a long side and a certain thickness. Thus, the short sides extend in the longitudinal direction, while the long sides extend in the radial direction. The three power source connecting end members 13 preferably lie in the same plane perpendicular to longitudinal axis 100.

The three

busbars

3, 4, 5 are arranged overlapping in the circumferential direction. The

busbars

3, 4, 5 each have a

base portion

30, 40, 50, which connects the coil connection end element 14 to the respective power source connection end element 13. The first and

second busbars

3, 5 are spaced from each other and the

base sections

30, 50 lie in the same plane perpendicular to the longitudinal axis. The

base sections

30, 50 of the two

busbars

3, 5 have a ring-segment-shaped form corresponding to the ring shape of the busbar holder. The ring segments of the two

busbars

30, 50 have the same radius. In the assembled state, the two ring segments partially cover the end sides of the coil 8. In the circumferential direction, an intermediate third busbar 4 is arranged between the two

busbars

3, 5, which third busbar is partially covered in the circumferential direction by the first and

second busbars

3, 5. The base section 40 of the third busbar likewise has the shape of a ring segment. But with a radius larger than the radius of the first and second busbar, so that a distance a is formed in the radial direction between the first and

second busbar

3, 5 and the third busbar 4. Preferably, the coil connection end elements of the third busbar are arranged in the radial direction between the

base sections

30, 50 of the first and second busbars and the base section 40 of the third busbar. The base section 40 of the third busbar lies in a different plane perpendicular to the longitudinal axis than the two

other base sections

30, 50. In the assembled state, the base section 40 of the third busbar is located between the stator 6 and the

base sections

30, 50 of the first and second busbars. The radius of the base section 40 of the third busbar is arranged such that this base section 40 is located outside the coil 8 and the positioning mechanism 9 in the radial direction. Since the coil 8 and the positioning mechanism 9 protrude outside the stator core 7 in the longitudinal direction, the base body section of the third busbar can be placed in the existing free space above the stator 7. Thereby, the axial projecting amount of the third bus bar 4 on the stator end side is small. This makes it possible to provide a motor having a small axial height. The stator 6 with the busbar unit 1 can be installed in an electric machine.

Fig. 5 shows a coolant pump 16 with the aforementioned electric machine 17, the electric machine 17 having a rotor 18 and a stator 6, the stator 6 having a busbar unit 1. The coolant pump 16 is configured as a dry rotary pump. The motor 17 is a brushless dc motor. In particular, coolant pumps are used in motor vehicles.

Claims

1. Pump (16) equipped with an electric machine (17) having a rotor (18) which can be rotatably mounted about a rotational axis (100) and a stator (6) which surrounds the rotor (18) on the outside and which has a stator core (7) and a coil (8) wound on the stator core (7), the winding being formed by a winding wire having a winding wire end (12), and the winding wire end (12) being electrically connected at the end side to at least three busbars (3, 4, 5), the at least three busbars (3, 4, 5) having a coil connection end element (14), a power source connection end element (13) and a ring-segment-type base body segment (30, 40, 50), the base segment (30, 40, 50) connecting the coil connection end element (14) to the power source connection end element (13), and the first busbar (3) and the second busbar (5) in the circumferential direction around the rotational axis (100) Spaced from each other and the base body sections (30, 50) are arranged in one and the same plane perpendicular to the axis of rotation (100), and a third busbar (4) is arranged between the first busbar (3) and the second busbar (5) in a circumferential direction around the axis of rotation, characterized in that the base body section (40) of the third busbar is arranged in a plane perpendicular to the axis of rotation between the end side of the stator and the plane defined by the base body sections (30, 50) of the first and second busbars.

2. Pump according to claim 1, characterized in that the base section (40) of the third busbar is arranged outside the coil (8) in a radial direction with respect to the axis of rotation (100), and the base sections (30, 40) of the first and second busbars at least partially cover the coil (8) in a radial direction.

3. Pump according to claim 1 or 2, characterized in that the base section (30) of the first busbar and the base section (40) of the second busbar have the same radius.

4. Pump according to any one of the preceding claims, characterized in that the busbars (3, 4, 5) are at least partially contained on a busbar support (2) fixed on top of the stator (6).

5. Pump according to claim 4, characterized in that the coil (8) is surrounded radially on the outside by a positioning means (9) on which the busbar holder (2) is held.

6. Pump according to claim 5, characterized in that the base section (40) of the third busbar is arranged outside the positioning means (9) in a radial direction with respect to the axis of rotation (100).

7. Pump according to any one of the preceding claims, characterized in that the coil connection end element (14) has a substantially U-or V-shaped shape and extends in a plane perpendicular to the axis of rotation (100).

8. Pump according to claim 7, characterized in that the coil connection end elements (14) each enclose one of the winding wire ends (12) which extend substantially parallel to the longitudinal direction.

9. Pump according to claim 7 or 8, characterized in that the coil connection end element (14) is formed by a bend of the busbar remote from the top of the stator.

10. Pump according to any one of the preceding claims, characterized in that the distance in the radial direction between the base section (40) of the third busbar and the base sections (30, 40) of the first and second busbars is chosen to be of such a size that: the coil connecting end elements (14) can be accommodated between the base body section (40) of the third busbar and the base body sections (30) of the first busbar and the base body section (40) of the second busbar, respectively.

11. Pump according to any one of the preceding claims, characterized in that the third busbar (4) is partially covered by the first busbar (3) and the second busbar (5).

12. Pump according to any of the preceding claims, characterized in that the power source connection end element (13) has a bend in the direction of the top of the busbar towards the stator and extends parallel to the axis of rotation.

13. Pump according to any of the preceding claims, characterized in that the pump (16) is used for a coolant pump of a motor vehicle.

14. A pump according to any preceding claim, wherein the pump (16) is a dry rotor pump.