JP2024041397A - motor - Google Patents

Abstract

[Problem] To provide an inverter-integrated motor that can shorten the axial length of the motor. [Solution] The motor of the present invention comprises a rotor that can rotate around its axis, a stator having coils in slots in a stator core to rotate the rotor, and a housing that covers and fixes the stator. The housing has a cooling path in at least a portion that covers the outer circumferential surface of the stator, and electronic components of an inverter are disposed radially outward of the stator and inside the cooling path, so that the motor and electronic components can be cooled simultaneously, and the axial length of the motor can be shortened to make it more compact. [Selected Figure] Figure 1

Description

The present invention relates to a motor, and more particularly to an inverter-integrated motor that can be miniaturized.

2. Description of the Related Art Inverter-integrated motors are known in which an inverter that applies voltage to a motor coil is integrated with a motor.

Patent Document 1 describes an inverter-integrated motor in which a cooling fan is provided on the rotating shaft of the motor, cooling air is sucked through an opening provided in the housing, and the cooling air flow that cools the inverter is sent to the motor side. It is disclosed that miniaturization is possible while ensuring cooling performance.

Japanese Patent Application Publication No. 2004-274992

However, the inverter-integrated motor requires space in the axial direction because the motor and the inverter components are arranged side by side in the axial direction.

The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide an inverter-integrated motor that can shorten the length of the motor in the axial direction.

As a result of extensive studies to achieve the above object, the inventor of the present invention has discovered that the electronic components of the inverter that supplies power to the coils of the motor are arranged radially outside the motor and inside the cooling path provided in the housing. The inventors have discovered that the above problems can be solved, and have completed the present invention.

That is, the motor of the present invention includes a rotor that is rotatable about its axis, a stator that has a coil in a slot of a stator core and rotates the rotor, and a housing that covers and fixes the stator.
The housing has a cooling passage at least in a portion covering the outer peripheral surface of the stator, and the electronic components of the inverter are arranged radially outside the stator and inside the cooling passage. do.

According to the present invention, since the electronic components of the inverter are arranged radially outside the motor and inside the cooling path provided in the housing, the motor and electronic components can be cooled at the same time. It is possible to provide an inverter-integrated motor that can be shortened in length and downsized.

1 is a sectional view of a main part of an example of a motor according to the present invention taken in a direction perpendicular to an axis; FIG. FIG. 3 is a diagram showing magnetic flux of a stator in which a recessed portion is formed. 1 is a sectional view of a main part of an example of the motor of the present invention taken in the axial direction.

The motor of the present invention will be explained in detail.
FIG. 1 shows a cross-sectional view of the motor of the present invention taken in a direction perpendicular to the shaft.
Note that in FIG. 1, the coil and the substrate are omitted.

As shown in FIG. 1, the motor of the present invention includes a rotor 1 rotatable around an axis, a coil 22 in a slot of a stator core 21, and a stator 2 that rotates the rotor 1 and supplies power to the coil 22. The inverter 3 that controls the frequency of the electric power and the rotational speed of the motor is housed in one housing 4, and is an integrated inverter motor.

Since the motor section consisting of the stator 2 and the rotor 1 generates heat due to losses such as copper loss and iron loss, a structure for dissipating heat to the outside of the motor is essential for a vehicle motor that operates continuously.

The housing 4 of the present invention covers the stator 2 from its outer circumferential side, and the inner circumferential surface of the housing 4 contacts the outer circumferential surface of the stator 2 to fix the stator 2, and at least the portion that covers the outer circumferential surface of the stator 2 A cooling path 41 is provided in the cooling path 41, and the heat of the motor section is transferred to the cooling water flowing through the cooling path 41 to remove the heat.

Furthermore, since the life of the inverter tends to decrease as the temperature rises, the inverter is generally installed at a location away from the motor section so as not to be affected by heat.

In the motor of the present invention, the electronic components 31 of the inverter are arranged radially outside the stator 2 and inside the cooling path 41, and the electronic components 31 are brought close to the cooling path 41, so that the electronic components 31 are separated from the electronic components 31. Improves heat removal efficiency.

Therefore, in order to prevent the inverter's electronic components 31 from being affected by the heat of the motor, the inverter's electronic components 31 and the motor section do not need to be spaced apart and arranged side by side in the axial direction, so that the inverter's electronic components 31 generate heat. It is possible to arrange the motor near the outside in the radial direction of the stator 2, and the length in the axial direction of the motor can be shortened.

Furthermore, since the electronic components 31 of the inverter and the motor section can be cooled simultaneously, the length of the cooling path 41 can be shortened, and the overall size of the motor can be reduced. The amount of power required for cooling can also be reduced.

The cooling path 41 of the housing 4 is made of a material with high thermal conductivity, and examples of the material with high thermal conductivity include aluminum and aluminum alloy.

Furthermore, as shown in FIG. 1, it is preferable that a recess 23 be formed in the outer peripheral surface of the stator 2, and that the electronic components 31 of the inverter be disposed in the region where the recess 23 is formed.

The magnetic field generated from the coil 22 provided in the slot of the stator core 21 is generated in the axial direction around which the coil 22 is wound according to the right-handed screw rule. The normal operation of the electronic components 31 of the inverter may be hindered due to the influence of the above.

The electromagnetic steel plate forming the stator core 21 has high magnetic permeability, and air has low magnetic permeability. Therefore, when the recess 23 is formed on the outer peripheral surface of the stator core 21, the recess 23 formed on the outer peripheral surface of the stator 2 has a high magnetic permeability as shown in FIG. In addition, the air makes it difficult for the magnetic flux to pass through, making the magnetic flux sparse, and it is possible to form areas where the magnetic flux is dense and areas where the magnetic flux is sparse on the outer peripheral surface of the stator core.

By arranging the electronic components 31 of the inverter in a region where the magnetic flux is sparse, it becomes less susceptible to the influence of the magnetic field, and normal operation of the inverter can be prevented from being disturbed.
The coil 22 may be wound in either concentrated winding or distributed winding.

Furthermore, the portion of the stator 2 where the recess 23 is formed is less likely to be affected by the magnetic field from the coil 22. The electronic component 31 may be placed in the recess 23 formed on the outer circumferential surface of the stator 2, but as shown in FIG. It may be arranged in a recess 23 formed on the outer peripheral surface. It is preferable to arrange the electronic component 31 on the surface of the housing 4 because the electronic component 31 can come into contact with the cooling path 41. Where to place the electronic component 31 is determined based on whether heat removal from the electronic component 31 is necessary or not.

By arranging the inverter's electronic components 31 within the recess formed in the housing 4, a gap is formed between the outer peripheral surface of the stator 2 and the inverter's electronic components 31, which not only makes it less susceptible to the influence of magnetic fields, but also Heat from the stator 2 is less likely to be transmitted and the electronic components 31 of the inverter are closer to the cooling path 41, so heat removal efficiency is improved.

The shape of the recess 23 of the stator 2 may be a shape and size that matches the shape of the electronic component 31 of the inverter and makes the electronic component 31 less susceptible to the influence of the magnetic field, but it may be a groove extending in the axial direction. It is preferable.

The stator core 21 is formed by laminating a plurality of electromagnetic steel plates, so if the shape of the recess 23 of the stator 2 is a groove extending in the axial direction, multiple types of electromagnetic steel plates with different shapes are used to form the recess 23. Since the stator core 21 having the concave portion 23 can be formed by laminating one type of electromagnetic steel sheets having the same shape, the cost can be reduced.

It is preferable that the electronic component 31 disposed in the region of the outer circumferential surface of the stator 2 where the magnetic flux is sparse is a discrete component.

A discrete component is an electronic component that has a single function, and a plurality of these discrete components are combined to form an electronic circuit that achieves a desired function.

Since the electronic component 31 placed in the area where the magnetic flux is sparse is a small discrete component rather than a module in which the entire electronic circuit is integrated, the recess 23 formed in the stator 2 can be made smaller. It is possible to minimize the influence on the magnetic circuit design.

Among the discrete components, power semiconductors that control and supply electrical energy are easily affected by magnetic fields, so it is preferable to prioritize them and place them in the region where the magnetic flux is sparse.

Examples of the power semiconductor include an insulated gate bipolar transistor (IGBT) and a diode, and these power semiconductors are arranged so that the distance from the coil 22 wound around the slot of the stator core 21 is equal , as shown in FIG. 1, it is preferable that they are evenly distributed and arranged on the outer circumferential surface of the stator.

As shown in FIG. 3, the board 32, which forms an inverter circuit by combining a plurality of the above-mentioned discrete components, has a donut shape with an outer diameter that is approximately the same as the outer diameter of the stator 2 so as to avoid the rotor shaft 12. It can be placed at the axial end of the stator 2 with the surface facing in the direction perpendicular to the axis.

By arranging the donut-shaped substrate 32 as described above, it is possible to shorten the distance between the substrate 32 and the discrete components placed in the area where the magnetic flux is sparse, and it is possible to shorten the distance between the discrete components and the coil 22. They can be electrically connected to form an inverter circuit.

Since the motor of the present invention can be shortened in length in the axial direction, when the motor is placed horizontally in a vehicle, it is possible to avoid damage to the motor due to interference from side members deformed during a vehicle collision. In addition, the length of the shaft that transmits the output from the transmission provided at the end of the motor to the wheels can be made approximately equal on the left and right sides, which helps to compensate for the difference in torsion caused by the difference in the length of the left and right shafts. Easy to correct.

1 Rotor 11 Rotor core 12 Rotor shaft 2 Stator 21 Stator core 22 Coil 23 Recess 3 Inverter 31 Electronic components (discrete components)
32 Board 33 Smoothing capacitor 34 PN connector 4 Housing 41 Cooling path

Claims (5)

A rotor rotatable about an axis;
a stator having coils in slots of a stator core for rotating the rotor;
a housing that covers and fixes the stator,
the housing has a cooling passage at least in a portion covering an outer circumferential surface of the stator,
A motor, characterized in that electronic components of an inverter are arranged radially outside the stator and inside the cooling path. The stator has a recess in a part of an outer circumferential surface as viewed in the axial direction,
2. The motor according to claim 1, wherein the electronic component is disposed in the portion where the recess is formed. The motor according to claim 2, wherein the recess is a groove extending in the axial direction. The motor according to claim 3, wherein the electronic component is a discrete component. having a substrate at an axial end of the stator;
The above-mentioned substrate is arranged with its main surface in a direction perpendicular to the axis,
A terminal of the discrete component and a coil end of the coil are fixed to the board,
The motor according to claim 4, wherein the discrete component and the coil are electrically connectable.

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