Electric motor with compact busbar unit
By adopting a compactly arranged three busbar design in the brushless DC motor, the problem of excessive axial extension size of the stator laminate is solved, reducing the height of the motor structure and saving space, while reducing the risk of electrical short circuit.
Patent Information
- Application Number
- CN202080087678.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2019-12-18
- Filing Date
- 2020-12-09
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2040-12-09
AI Technical Summary
The extended size of the stator laminates of existing brushless DC motors in the axial direction is large, resulting in an increase in the structural height of the motor. Especially when space is limited in motor vehicle applications, it is difficult to meet the dual requirements of power and size.
The compact arrangement of three busbars is adopted, wherein the main parts of the first and second busbars extend in two vertical planes and the third busbars are in the circumferential position, through which the axial extension dimension of the busbars is reduced , and the design of the busbar seat is to be partially accommodated on the top side of the stator, simplifying installation.
It effectively reduces the axial extension size of the stator laminate and the axial structural height of the motor, saves structural space, reduces the risk of electrical short circuits, and improves installation ease.
Smart Images
Figure CN114830503B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to electric motors. Background Art
[0002] The brushless DC motor of the relevant configuration is called an inner rotor motor, which has a rotor connected to the motor shaft and rotatably mounted in the housing. The rotor is equipped with a plurality of permanent magnets. A stator is arranged around the motor, and the stator is equipped with a plurality of windings on the core. Under appropriate control, the windings generate a magnetic field that drives the rotor to rotate. The windings are usually wound in three phases and are correspondingly equipped with electrical terminals, through which the windings can be connected to the control unit (ECU). At low powers, the busbar can be designed as a conductive circuit foil. At higher powers such as here, the winding connections are contacted through a busbar consisting of copper plates.
[0003] For the geometric description of the electric motor, on the one hand, the rotation axis of the electric motor is assumed to be the central axis and the axis of symmetry. The stator is arranged concentrically with the rotation axis and the rotor. The rotation axis simultaneously defines the axial direction. In addition, the radial direction, which indicates the distance from the central axis, and the circumferential direction, which is characterized by being tangential to a certain radius arranged in the radial direction, are mentioned with respect to the central axis. The stator terminal side, which is connected to the busbar assembly here, is described as the top side of the stator.
[0004] In the case of the electric motors discussed here, in addition to the power data and the weight, the dimensions are also important, especially when the electric motors are used in motor vehicles. The installation space in a motor vehicle is usually limited, and the requirements set by the motor vehicle manufacturer must be observed. Therefore, there are always requirements for the design of the electric motor, for example, a certain axial length in the direction of the center axis should not be exceeded. In this case, the power data required by the electric motor essentially determines the axial length of the stator laminations and the rotor with the electromagnets mounted thereon. The busbar units required for contacting the stator windings contribute to this axial length.
[0005] Thus, JP2014-158421A discloses an electric motor, in which a busbar unit having three busbars is arranged axially above the stator laminations and connected to the winding connections. The busbar unit comprises a plurality of busbars, which are arranged concentrically with respect to the central axis in a semicircular shape. The plurality of busbars are arranged axially one above the other. The plurality of busbars and the required electrical isolation between them contribute to the axial length of the stator laminations, since they are arranged on the stator above the winding package. Summary of the invention
[0006] The object of the present invention is to develop an electric motor in such a way that the axial extension of the stator core and thus also the axial overall height of the electric motor are reduced.
[0007] This task is accomplished by an electric motor.
[0008] Therefore, a motor is provided, which has a rotor rotatably mounted about a rotation axis and a stator having a stator core and a coil wound on the stator core surrounding the rotor on the outside, wherein the winding is composed of a winding wire having a winding wire end, and the winding wire end is in conductive contact with three busbars at the end side to form a phase, wherein the three busbars respectively have a power connection terminal for conductively contacting the busbar with a power source and a ring segment-shaped main body for electrically connecting the busbar to the winding wire end, wherein the main body of the first busbar is arranged in a first plane perpendicular to the rotation axis, and the main body of the second busbar is arranged in a second plane perpendicular to the rotation axis and spaced from the first plane, and the main body of the first busbar extends clockwise from the power connection terminal of the first busbar, the main body of the second busbar extends counterclockwise from the power connection terminal of the second busbar, the power connection terminals of the first and second busbars are spaced from each other, and the power connection terminal of the third busbar is located between the first and third power connection terminals in the circumferential direction. The third busbar has a first region extending clockwise from the power connection terminal thereof and located in the second plane, and a second region extending counterclockwise from the power connection terminal thereof and located in the first plane.
[0009] The arrangement of the busbars is very compact, since only two planes are required and the axial extension of the busbar socket can therefore be kept small.
[0010] Preferably, the main bodies of the first, second and third busbars have the same radius and overlap in the axial direction.
[0011] Advantageously, the busbar is at least partially accommodated in a busbar holder which is fixed to the top side of the stator. This arrangement simplifies installation.
[0012] Preferably, the main body of the third busbar is completely covered by the first busbar and the second busbar in a plan view. In other words, the covering is located outside the power connection terminal.
[0013] In a preferred embodiment, the first region and the second region of the third busbar each extend over approximately 105°.
[0014] Advantageously, the first and second busbars are arranged overlapping at their ends facing away from the power connection terminals in plan view.
[0015] In this preferred embodiment, it is advantageous if the first and second busbars each have a main portion extending over approximately 210°.
[0016] The third busbar preferably has a shoulder in the axial direction on the main body, and the shoulder is used for transformation between planes.
[0017] The power connection terminals of the first busbar are preferably located in a first plane, the power connection terminals for the second busbar are located in a second plane, and the power connection terminals of the third busbar are located axially between the two planes.
[0018] The distance between the two planes results in the busbars being electrically isolated from each other.
[0019] This busbar embodiment is advantageous when the stator is wound according to the following scheme:
[0020] Starting from the end of the winding wire, winding the first stator tooth in a first direction,
[0021] Leading the winding wire to a second stator tooth immediately following the first stator tooth in the first circumferential direction, and
[0022] winding the second stator tooth in a second direction opposite to the first direction, and wherein,
[0023] The winding pairs are designed to be supplied with current in such a way that the direction of the current flow through the circumferentially opposite winding pairs is reversed, so that a south pole and a north pole are respectively opposite each other in the circumferential direction in the stator.
[0024] The stator preferably has uniformly spaced stator teeth which protrude inwardly from the stator core and leave a cylindrical inner region free and which are wound in pairs with winding wire to form winding pairs.
[0025] The first direction and the corresponding winding direction are identical for each winding pair.
[0026] The advantage obtained by the winding concept is that the winding of each tooth pair is identical and thus different components can be avoided, which in turn saves costs. In addition, the risk of electrical short circuits between the phases is significantly reduced because the intersection of the metal wires is avoided.
[0027] Preferably, each winding pair is wound with a separate winding wire. However, it can also be provided that at least two winding pairs are wound with a separate winding wire to form a coil chain.
[0028] In one embodiment, the stator has six winding pairs. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] A preferred embodiment of the present invention will be explained in detail below with reference to the drawings. The same components or components having the same functions are marked with the same reference numerals in the drawings, wherein:
[0030] Figure 1 A schematic top view of the stator is shown.
[0031] Figure 2 Show Figure 1 The schematic diagram of the stator and busbar is shown in Figure 1.
[0032] Figure 3 Show three roots such as Figure 2 A schematic diagram of the power supply terminals of the busbar is shown, and
[0033] Figure 4 A schematically illustrated electric motor with a stator and busbars is shown in longitudinal section. DETAILED DESCRIPTION
[0034] exist Figure 1 1 shows a stator 1 of an electric motor. The stator 1 of the electric motor is composed of an iron core and has three phase windings 3 composed of a plurality of coils 2 on the poles to form a four-pole motor, wherein the coils 2 are wound on the respective poles. The stator teeth extend inward from the iron core and leave a cylindrical inner area in which the motor rotor (not shown) rotates during operation. The three phases U, V, and W are formed by wiring winding pairs 4 connected in a wiring manner, so that two parallel current paths appear in the delta circuit. The first coil of each winding pair 4 is formed by winding a tooth counterclockwise. This is followed by the second tooth of the winding pair 4 that is adjacent to the first tooth that is wound clockwise in the clockwise direction without interruption. The winding wire ends 7 of the winding pair 4 are electrically contacted toward the center of the stator. The winding of all six winding pairs 4 is carried out according to the same scheme. The required direction of rotation of the magnetic poles in the winding pair 4 is obtained by reversing the electrical terminals and the direction of current flow. The wire ends connected to each other in a wiring manner are therefore located at an angle of approximately 150°. The respective contact points of one phase are spread over an area of approximately 210°.
[0035] Figure 2 The view from above schematically shows Figure 1 The busbar unit 8 of the stator 1 shown. The busbar unit 8 comprises a busbar seat (not shown) and three busbars 9, 10, 11 mounted on the busbar seat. The busbars 9, 10, 11 are made of a conductive material, preferably a metal, especially copper. The busbar seat is at least partially or completely made of an electrically insulating material, so that a short circuit between the busbars 9, 10, 11 can be effectively prevented. The busbar seat is preferably manufactured by die casting and extends over a part of the busbars 9, 10, 11. In this way, a fixed and carefully defined physical connection between the busbar seat and the busbars 9, 10, 11 can be provided. The busbar seat is designed to be located on one axial side (top side) of the stator.
[0036] The busbar unit 8 is designed to electrically contact the coils 2 of the stator 1 by means of busbars 9, 10, 11. The coils 2 are divided into three phase groups U, V, W. The four winding wire ends 7 each contact a busbar. The busbar of one phase extends over an area of 210°. Each busbar 9, 10, 11 has a power connection terminal 12, 13, 14, which is designed to electrically connect the busbar to a power source.
[0037] The busbars 9, 10, 11 are arranged along a circumference with a fixed radius with main body parts 9', 10', 11' respectively. The main body parts 9', 10', 11' are formed in the shape of ring segments.
[0038] exist Figure 2 In the view of FIG. 1 , the busbars are movably located at different radii in order to illustrate the arrangement of the busbars on different planes. The arrangement of the busbars will be described below.
[0039] The first busbar 9 extends through an area of about 210° along the circumference with its main body 9'. The first busbar is located in the first plane E1. It has a terminal 12 for a power supply at one end of the main body 9'. From the power connection terminal 12, the main body 9' extends clockwise. The second busbar 10 also extends through an area of about 210° along the circumference with the same radius as the first busbar with its main body 10'. The second busbar is located in the second plane E2. It has a terminal 13 for a power supply at one end of the main body 10'. From the power connection terminal 13, the main body 10' extends counterclockwise. The two busbars 9 and 10 are arranged overlapping at their ends away from the power supply in a top view. The two planes E1 and E2 are selected here so that the ends are overlapped in the axial direction, but not in contact and are electrically isolated from each other. The two busbars have a spacing a in the axial direction.
[0040] The third busbar 11 has a power connection terminal 14, which is located between the terminals 12, 13 of the first and second busbars 9, 10 in the circumferential direction. All three terminals 12, 13, 14 are adjacent to each other. Starting from the third power connection 14, the third busbar 11 extends on the second plane E2 in the direction of the first busbar 9 in the first area 11", and extends on the first plane E1 in the direction of the second busbar 10 in the second area 11"'. The third busbar 11 is therefore arranged overlapping with the first busbar 9 in the first area 11" and overlapping with the second busbar 10 in the second area 11"' in a plan view. Each area 11", 11"' extends in the form of a ring segment over approximately 105°.
[0041] Figure 3 and Figure 4 FIG. 1 shows the arrangement of the busbars along the axial direction 100. Figure 3As shown, the third busbar 11 changes planes on the two halves of the main body 11'. The main body of the third busbar is therefore dispersed into two areas 11" and 11"'. Therefore, the third busbar 11 has a shoulder 15 in the main body 11'. The power connection terminals 12 of the first busbar 9 are located in the first plane E1, the terminals 13 for the power supply of the second busbar 10 are located in the second plane E2, and the power connection terminals 14 of the third busbar 11 are axially located between these two planes E1 and E2. The three busbars 9, 10, and 11 are dispersedly arranged on only two planes E1 and E2. Therefore, the axial extension of the stator laminations and thus the axial structural height of the motor are kept to a minimum to save structural space.
[0042] Figure 4 An electric motor 16 is schematically shown, which has a stator 1 equipped at its end with a busbar unit 8. The busbars 10, 11 are located in two different planes E1, E2. The third busbar 11 is contacted with the winding wire end 7 of the associated coil.
Claims
1. An electric motor (16), comprising a rotor and a stator (1), wherein the rotor is mounted so as to be rotatable about a rotation axis (100), the stator (1) surrounds the rotor on the outside and comprises a stator core and a coil (2) wound on the stator core, wherein: The phase winding (3) is composed of a winding wire having a winding wire end (7), and the winding wire end (7) is in conductive contact with three busbars (9, 10, 11) at the end side to form a phase, wherein the three busbars (9, 10, 11) respectively have power connection terminals (12, 13, 14) for making the busbar in conductive contact with a power source and ring segment-shaped main parts (9', 10', 11') for electrically connecting the busbar to the winding wire end. , wherein a main body (9') of the first busbar (9) is arranged in a first plane (E1) perpendicular to the rotation axis (100), and wherein a main body (10') of the second busbar (10) is arranged in a second plane (E2) spaced from the first plane (E1) and perpendicular to the rotation axis (100), wherein the main body (9') of the first busbar (9) is connected from a power supply connection of the first busbar (9) to a power supply connection of the first busbar (9) The invention relates to a third busbar (10) having a first power connection terminal (12) and a second power connection terminal (13) arranged in a clockwise direction from the power connection terminal (12), and the main body (10') of the second busbar (10) extends counterclockwise from the power connection terminal (13) of the second busbar (10), and the power connection terminal (12) of the first busbar (9) and the power connection terminal (13) of the second busbar (10) are spaced from each other, and wherein the power connection terminal (14) of the third busbar (11) is circumferentially located between the power connection terminal (12) of the first busbar (9) and the power connection terminal (13) of the second busbar (10), characterized in that the third busbar (11) has a first area (11") extending clockwise from its power connection terminal (14) and located in the second plane (E2), and a second area (11'") extending counterclockwise from its power connection terminal (14) and located in the first plane (E1).
2. The electric motor according to claim 1, characterized in that: The main body (9') of the first busbar (9), the main body (10') of the second busbar (10) and the main body (11') of the third busbar (11) have the same radius.
3. The electric motor according to claim 1 or 2, characterized in that: The first busbar (9), the second busbar (10) and the third busbar (11) are at least partially accommodated in a busbar seat, which is fixed on the top side of the stator (1).
4. The electric motor according to claim 1 or 2, characterized in that: The main body (11') of the third busbar (11) is completely covered by the first busbar (9) and the second busbar (10) in a plan view.
5. The electric motor according to claim 1 or 2, characterized in that: The first region (11") and the second region (11'") of the third busbar (11) each extend over 105°.
6. The electric motor according to claim 1 or 2, characterized in that: The first busbar (9) and the second busbar (10) are arranged overlapping at their ends away from the power connection terminals in a plan view.
7. The electric motor according to claim 1 or 2, characterized in that: The first busbar (9) and the second busbar (10) each have a main body portion extending over approximately 210°.
8. The electric motor according to claim 1 or 2, characterized in that: The third busbar (11) has a shoulder (15) in the axial direction in the main body portion (11').
9. The electric motor according to claim 1 or 2, characterized in that: The power connection terminal (12) of the first busbar (9) is located in the first plane (E1), the power connection terminal (13) for the power supply of the second busbar (10) is located in the second plane (E2), and the power connection terminal (14) of the third busbar (11) is axially located between the first plane (E1) and the second plane (E2).
10. The electric motor according to claim 1 or 2, characterized in that: The distance between the first plane (E1) and the second plane (E2) causes the first busbar (9), the second busbar (10) and the third busbar (11) to be electrically isolated from each other.