JP7367384B2 - motor unit - Google Patents

Description

The present invention relates to a motor unit.

In recent years, development of motor units installed in hybrid vehicles has been actively conducted. Such a motor unit includes a motor, an inverter, and a power line (bus bar) that electrically connects these to each other (for example, Patent Document 1).

Japanese Patent Application Publication No. 2010-268633

If the power supply path by the bus bar becomes longer, there is a risk that not only power loss will increase but also the motor unit will become larger. Therefore, the inventors of the present invention have devised a configuration in which a busbar and a busbar holder that holds the busbar are disposed within a housing that accommodates a motor, thereby reducing the size of the busbar. Furthermore, in such a configuration, there has been a need for a method of easily increasing the positioning accuracy when assembling the bus bar holder.

In view of the above-mentioned background, one aspect of the present invention aims to provide a motor unit with improved positioning accuracy of a busbar unit within a housing.

One aspect of the motor unit of the present invention includes a motor having a rotor that rotates around a motor shaft and a stator located radially outside of the rotor, an inverter that supplies power to the motor, and a motor that connects the motor and the inverter. and a housing that accommodates the motor and the busbar unit. The stator includes an annular stator core centered around the motor shaft, and a coil wound around the stator core. The busbar unit includes a plurality of busbars made of conductors and connected to the coils, and a busbar holder that holds the busbars. The bus bar holder is fixed to a fixed surface of the inner wall surface of the housing that faces one side in the axial direction. The bus bar holder contacts an outer peripheral surface of the stator core.

According to one aspect of the present invention, a motor unit is provided in which the positioning accuracy of a busbar unit within a housing is improved.

FIG. 1 is a schematic cross-sectional view of a motor unit of one embodiment. FIG. 2 is a perspective view of the busbar holder and housing of one embodiment. FIG. 3 is a cross-sectional view showing a process of assembling the bus bar holder of one embodiment to the housing. FIG. 4 is a side view of the motor unit of one embodiment.

Hereinafter, a motor unit according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical idea of the present invention.

In the following description, the vertical direction will be defined based on the positional relationship when the motor unit 1 of this embodiment shown in each figure is mounted on a vehicle located on a horizontal road surface. In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction is simply referred to as the "upper side", and the lower side in the vertical direction is simply referred to as the "lower side". The X-axis direction is a direction perpendicular to the Z-axis direction, and is the front-rear direction of the vehicle in which the motor unit 1 is mounted. The Y-axis direction is a direction perpendicular to both the X-axis direction and the Z-axis direction, and is the left-right direction (vehicle width direction) of the vehicle. In this embodiment, the +Y side is one axial side of the motor shaft J, and the -Y side is the other axial side of the motor shaft J.

In the following explanation, unless otherwise specified, the direction parallel to the motor axis J of the motor 2 (Z-axis direction) is simply referred to as the "axial direction", and the radial direction centered on the motor axis J is simply referred to as the "radial direction". The circumferential direction centered on the motor shaft J, that is, the circumferential direction around the motor shaft J is simply referred to as the "circumferential direction."

Hereinafter, a motor unit 1 according to an exemplary embodiment of the present invention will be described.
The motor unit 1 of this embodiment is mounted on a vehicle that uses a motor as a power source, such as a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV), and is used as the power source.

FIG. 1 is a schematic cross-sectional view of the motor unit 1. As shown in FIG.
The motor unit 1 includes a motor 2, a busbar unit 5, a housing 6, and an inverter unit 8. Note that the motor unit 1 may include a speed reduction device (not shown) that slows down the rotation of the motor 2 and outputs the speed to the outside.

<Motor>
The motor 2 of this embodiment is a three-phase motor. The motor 2 is housed inside the housing 6. The motor 2 includes a rotor 20 that rotates around a motor shaft J that extends in the horizontal direction, a stator 30 that is located on the outside of the rotor 20 in the radial direction, and a pair of bearings 26 and 27 that rotatably support the rotor 20. Be prepared. The motor 2 of this embodiment is an inner rotor type motor.

The rotor 20 rotates when alternating current is supplied from the inverter unit 8 to the stator 30 . The rotor 20 includes a shaft 21, a rotor core 24, and a rotor magnet (not shown). The rotor 20 (that is, the shaft 21, the rotor core 24, and the rotor magnet) rotates around a motor shaft J that extends horizontally and in the width direction of the vehicle.

The shaft 21 extends along the axial direction centering on the motor shaft J. The shaft 21 rotates around the motor axis J. The shaft 21 is rotatably supported by a pair of bearings 26 and 27. The pair of bearings 26 and 27 are located on both sides of the shaft 21 in the axial direction, with the rotor core 24 in between. A pair of bearings 26 and 27 are held in the housing 6.

The rotor core 24 is constructed by laminating silicon steel plates. The rotor core 24 is a cylindrical body extending along the axial direction. A plurality of rotor magnets (not shown) are fixed to the rotor core 24 . The plurality of rotor magnets are arranged along the circumferential direction with alternating magnetic poles.

The stator 30 includes a stator core 32, a coil 31 wound around the stator core 32, and an insulator (not shown) interposed between the stator core 32 and the coil 31. Stator 30 is held in housing 6.

The stator core 32 has an annular shape centered on the motor shaft J. The stator core 32 has a plurality of magnetic pole teeth (not shown) radially inward from the inner peripheral surface of the annular yoke. A coil wire is wound between the magnetic pole teeth. The coil wire wrapped around the magnetic pole teeth constitutes a coil 31. That is, the coil 31 is wound around the stator core 32 via the insulator. The coil wire extending from the coil 31 is connected to the inverter unit 8 via the bus bar 50 of the bus bar unit 5.

<Housing>
Housing 6 accommodates motor 2 and busbar unit 5. A housing space 60 is provided inside the housing 6 . The motor 2 and the busbar unit 5 are located in the housing space 60. The accommodation space 60 has a motor accommodation area 60A that accommodates the motor 2, and a busbar unit accommodation area 60B that accommodates the busbar unit 5. The busbar unit housing area 60B is located on the radially outer side of the motor housing area 60A.

The housing 6 includes a housing body 65 and a closing member 61. The housing space 60 is a space surrounded by a housing body 65 and a closing member 61. The housing body 65 and the closing member 61 are made of aluminum die-casting, for example.

The housing body 65 has a cylindrical portion 66 that extends along the motor axis J, and a bottom portion 67 that closes one opening of the cylindrical portion 66. The housing body 65 opens in the axial direction of the motor 2. The opening of the housing body 65 faces one side in the axial direction (+Y side). The bottom 67 holds the bearing 27. The bottom portion 67 supports the shaft 21 via the bearing 27.

The cylindrical portion 66 of the housing body 65 is provided with an expanded portion 66a that extends outward in the radial direction. A busbar unit accommodating area 60B is provided inside the extended portion 66a. That is, the busbar unit 5 is arranged inside the extended portion 66a. The expanded portion 66a is provided with a housing through hole 65b that penetrates in the radial direction. That is, the housing 6 is provided with a housing through hole 65b that penetrates in the radial direction. A part of the bus bar 50 of the bus bar unit 5 passes through the housing through hole 65b.

The closing member 61 covers the opening of the housing body 65. The closing member 61 is fixed to the cylindrical portion of the housing body 65. The closing member 61 faces the bottom portion 67 in the axial direction. The closing member 61 holds the bearing 26. The closing member 61 supports the shaft 21 via the bearing 26.

The housing 6 has an inner wall surface 60a surrounding the accommodation space 60. A fixing surface 60b for fixing the busbar unit 5 is provided on the inner wall surface 60a. The fixed surface 60b faces one side in the axial direction (+Y side). A screw hole 60c extending along the axial direction is provided in the fixing surface 60b. A fixing screw 58 for fixing the busbar unit 5 is inserted into the screw hole 60c of the fixing surface 60b. The fixing structure between the housing 6 and the busbar unit 5 will be explained in detail later.

<Inverter unit>
Inverter unit 8 is fixed to the outer surface of housing 6. The inverter unit 8 includes an inverter 82 that supplies power to the motor 2, a control section 83 that controls the motor 2, and a case 80.

Case 80 houses an inverter 82 and a control section 83. The case 80 is provided with a case through hole 80a that communicates the inside and outside of the case 80. The case through hole 80a is continuous with the housing through hole 65b. A portion of the bus bar 50 of the bus bar unit 5 passes through the housing through hole 65b and the case through hole 80a, and is routed from the inside of the housing 6 to the inside of the case 80.

The inverter 82 converts a direct current supplied from an external device (not shown) into an alternating current and supplies the alternating current to the motor 2 . The inverter 82 includes, for example, a power board, a capacitor, a switching element, and the like. Inverter 82 is connected to an external power supply (not shown). The external power supply device is, for example, a secondary battery mounted on a vehicle.

Inverter 82 has three terminals 81. Terminal 81 is connected to bus bar 50 inside case 80 . That is, the inverter 82 is connected to the motor 2 via the bus bar 50.

<Busbar unit>
The busbar unit 5 is arranged in a busbar unit accommodation area 60B inside the housing 6. Busbar unit 5 connects motor 2 and inverter unit 8. The busbar unit 5 includes three busbars 50 and a busbar holder 55 that holds the busbars 50.

Bus bar 50 is made of a conductor. The three bus bars 50 are connected to the U-phase, V-phase, and W-phase coils 31 of the motor 2, for example. Further, the three bus bars 50 are respectively connected to three terminals 81 extending from the inverter unit 8. Bus bar 50 supplies alternating current output from inverter 82 of inverter unit 8 to motor 2 . Busbar 50 is fixed to busbar holder 55.

The bus bar 50 has a bus bar main body part 52 and a connection terminal part 51. The busbar main body portion 52 extends along the axial direction. A coil wire extending from the coil 31 of the stator 30 is connected to one end of the bus bar body 52 in the axial direction (+Y side).

The connection terminal portion 51 of the bus bar 50 extends radially outward from the end portion of the bus bar body portion 52 on the other axial side (−Y side). That is, the connection terminal portion 51 extends along the radial direction. The connection terminal portion 51 is connected to the inverter unit 8 through a housing through hole 65b provided in the housing 6.

The bus bar holder 55 is made of an insulating material. In this embodiment, the bus bar holder 55 is made of resin material. Busbar holder 55 holds three busbars 50. Bus bar holder 55 is fixed to housing 6. That is, the busbar unit 5 is fixed to the housing 6 at the busbar holder 55.

The bus bar holder 55 has a first opposing surface 55a facing inward in the radial direction and a second opposing surface 55b facing the other side in the axial direction (-Y side). The bus bar holder 55 contacts the fixing surface 60b of the housing 6 at the second opposing surface 55b. Further, the bus bar holder 55 contacts the outer peripheral surface 32a of the stator core 32 at the first opposing surface 55a.

FIG. 2 is a perspective view of the busbar holder 55 and the housing 6.
The first opposing surface 55a of the bus bar holder 55 is provided with a groove portion 56 extending along the axial direction. The groove portion 56 opens on one axial side in the end face of the bus bar holder 55 on one axial side (+Y side). Further, the end of the groove portion 56 on the other axial side (−Y side) is closed by a closing portion 57. The closing portion 57 is provided with a through hole 57a that penetrates along the axial direction. That is, the bus bar holder 55 is provided with a through hole 57a that passes through the bus bar holder 55 in the axial direction. A fixing screw 58 is inserted into the through hole 57a. The fixing screw 58 fixes the bus bar holder 55 to the housing 6 by being screwed into a screw hole 60c provided in a fixing surface 60b of the housing 6.

The second opposing surface 55b is provided with a protruding portion (convex portion) 59 that protrudes toward the other side in the axial direction. The protruding portion 59 has a rib shape that protrudes toward the other side in the axial direction (−Y side) and extends in the radial direction. Further, the fixing surface 60b of the housing 6 is provided with a groove (recess) 69 into which the protruding strip 59 fits. The groove 69 is recessed toward the other side in the axial direction (-Y side). The groove 69 extends in the radial direction. The groove 69 opens radially inward. The protruding portion 59 fits into the groove 69 .

FIG. 3 is a schematic cross-sectional view of the process of assembling the motor unit 1, showing a procedure for assembling the busbar unit 5 to the housing 6. The busbar unit 5 is fixed to the housing 6 by screws after the protruding portion 59 is moved and inserted along the direction in which the groove 69 extends.

According to this embodiment, the bus bar holder 55 is fixed to a fixing surface 60b facing one side in the axial direction among the inner wall surfaces of the housing 6 with one fixing screw 58. That is, only one fixing screw 58 is used to fix the bus bar holder 55 and the housing 6. Therefore, the number of parts of the motor unit 1 can be reduced. In addition, in the assembly process, the fixing screw 58 can be tightened only once, simplifying the assembly process. However, if only one fixing screw 58 is used, the bus bar holder 55 may rotate around the fixing screw 58, making it difficult to position the bus bar holder 55 with respect to the housing 6. According to this embodiment, the protruding portion 59 of the bus bar holder 55 fits into the groove 69 of the housing 6 . Therefore, the rotation of the bus bar holder 55 around the fixing screw 58 is suppressed, and the positioning of the bus bar holder 55 around the fixing screw 58 can be easily performed.

In the present embodiment, a case has been described in which the fixing surface 60b of the housing 6 is provided with the concave groove 69, and the second opposing surface 55b of the bus bar holder 55 is provided with the protruding portion 59. However, if one of the fixing surface 60b and the second facing surface 55b is provided with the protruding strip 59, and the other is provided with the groove 69 into which the protruding strip 59 fits, the above-mentioned effect can be obtained. be able to. Moreover, the above-mentioned effect can be obtained if the protruding stripes 59 are simply protrusions and the grooves 69 are recesses into which the protrusions fit.

According to this embodiment, the groove 69 extends along the radial direction and opens radially inward. Therefore, by moving the bus bar holder 55 in the radial direction, the protruding portion 59 can be inserted and fitted into the groove 69. Further, in this embodiment, the direction in which the groove 69 extends matches the direction in which the housing through hole 65b penetrates. That is, the housing 6 is provided with a housing through hole 65b that penetrates along the direction in which the groove 69 extends. Therefore, by inserting and fitting the protruding portion 59 into the concave groove 69, the connecting terminal portion 51 of the bus bar 50 extending radially outward can be easily inserted into the housing through hole 65b.

FIG. 4 is a side view of the motor unit 1. In FIG. 4, illustration of the closing member 61 is omitted.
The coil wires of each phase extending from the coil 31 are gathered together by a crimp terminal 31a. Further, the crimp terminal 31a is connected to the bus bar 50 by being screwed to the bus bar 50 in the fixing hole 32aa.

The first opposing surface 55a is curved concavely along the circumferential direction. The radius of curvature of the first opposing surface 55a matches the radius of curvature of the outer peripheral surface 32a of the stator core 32. Bus bar holder 55 contacts along outer peripheral surface 32a of stator core 32 at first opposing surface 55a.

According to this embodiment, the bus bar holder 55 can be positioned in the radial direction with respect to the motor 2. That is, the positional accuracy of the bus bar 50 with respect to the motor 2 can be improved. Therefore, when connecting the coil 31 and the bus bar 50, it becomes easy to align the crimp terminal 31a and the bus bar 50. Furthermore, since the positional accuracy of the bus bar 50 with respect to the crimp terminal 31a can be improved, the hole diameter of the fixing hole 32aa of the crimp terminal 31a can be reduced. Thereby, the size of the crimp terminal 31a can be reduced while ensuring the contact area between the bus bar 50 and the crimp terminal 31a. As a result, the motor unit 1 can be downsized.

In this embodiment, the bus bar holder 55 contacts the outer circumferential surface 32a of the stator core 32 at a first opposing surface 55a that is curved in a concave shape. Therefore, the bus bar holder 55 can be easily aligned in the assembly process.

Although the embodiments of the present invention have been described above, each configuration and combination thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other changes to the configurations may be made without departing from the spirit of the present invention. is possible. Moreover, the present invention is not limited by the embodiments.

DESCRIPTION OF SYMBOLS 1... Motor unit, 2... Motor, 5... Busbar unit, 6... Housing, 8... Inverter unit, 20... Rotor, 30... Stator, 31... Coil, 32... Stator core, 32a... Outer peripheral surface, 50... Bus bar, 51... Connection terminal portion, 55... Bus bar holder, 55a... First opposing surface, 55b... Second opposing surface, 57a... Through hole, 58... Fixing screw, 59... Convex strip (convex portion), 60a... Inner wall surface, 60b... Fixed surface, 60c...screw hole, 65b...housing through hole, 69...concave groove (recess), 82...inverter, J...motor shaft

Claims (6)

a motor having a rotor that rotates around a motor shaft and a stator located radially outside the rotor;
an inverter that supplies power to the motor;
a busbar unit connecting the motor and the inverter;
a housing that accommodates the motor and the busbar unit,
The stator is
an annular stator core centered on the motor shaft;
a coil wound around the stator core;
The busbar unit includes:
a plurality of bus bars made of conductors and connected to the coil;
a busbar holder that holds the busbar;
The bus bar holder is fixed to a fixed surface facing one side in the axial direction among the inner wall surfaces of the housing,
the bus bar holder contacts an outer peripheral surface of the stator core ;
A convex portion is provided on a second opposing surface facing the other side in the axial direction of the bus bar holder,
The fixing surface is provided with a recess that opens radially inward and into which the convex part fits.
motor unit. The bus bar holder has a first opposing surface that faces radially inward and curves concavely along the circumferential direction,
The motor unit according to claim 1, wherein the bus bar holder contacts along an outer peripheral surface of the stator core at the first opposing surface. The fixing surface is provided with a screw hole extending along the axial direction,
The bus bar holder is provided with a through hole that penetrates along the axial direction,
The motor unit according to claim 1 or 2, wherein a fixing screw screwed into the screw hole is inserted into the through hole. The motor unit according to claim 3, wherein the bus bar holder is fixed to the housing with one of the fixing screws. The motor unit according to any one of claims 1 to 4 , wherein the recess is a groove extending in a radial direction. The housing is provided with a housing through hole that penetrates along the extending direction of the groove,
The motor unit according to claim 5 , wherein the bus bar has a connection terminal portion that extends along the radial direction, passes through the housing through hole, and is connected to the inverter.

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