JP2002345188A - Dynamo-electric rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable direct cooling of permanent magnets effectively, without decreasing the output of a dynamo-electric machine. SOLUTION: In a rotor 11 rotating on the inner peripheral side of a stator, the permanent magnets 12 are inserted and fixed in magnet insertion holes 16, which are formed in a rotor core 13 and stretched in a rotor shaft direction. With respect to the rotation center of the rotor 11, the outer peripheries of the permanent magnets 12 are brought into contact with the magnet insertion holes 16, and cooling channels 15, which guide refrigerant along the magnet insertion holes 16 are formed on the inner peripheral surface of the permanent magnets 12. The cooling channel 15 is formed so that its section protrudes toward the center of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotating electric machine such as a permanent magnet type synchronous motor.

[0002]

2. Description of the Related Art A permanent magnet synchronous motor as disclosed in Japanese Patent Application Laid-Open No. H11-206063 has been proposed to enhance the cooling performance of a rotor of a permanent magnet synchronous motor.

As shown in FIG. 7, a plurality of permanent magnets 2 are arranged on a rotor core 3 of a rotor 1 of a synchronous motor at equal intervals on the same circumference around a rotating shaft 4, The section of the magnet insertion hole 5 into which the permanent magnet 2 is inserted is
Is set to be slightly larger than the cross section of, and the refrigerant flows through the gap 5a formed when the permanent magnet 2 moves outward by centrifugal force acting when the rotor 1 rotates, and the permanent magnet 2 is directly It is designed to cool down.

Since the performance of the permanent magnet 2 decreases when its temperature rises due to self-heating due to an internal eddy current and heat transfer due to the temperature rise of the stator winding, the permanent magnet 2 is directly cooled. , To avoid such problems.

[0005]

If there is a gap around the permanent magnet 2 disposed on the rotor 1, the gap becomes a large resistance to the flow of magnetic flux from the permanent magnet 2 to the stator, and the output of the motor Although the torque decreases, the gap 5a through which the coolant flows is located on the inner peripheral side of the permanent magnet 2 and there is no air gap on the outer peripheral side of the permanent magnet 2 on the stator side. Can be blocked.

However, on the other hand, the gap 5a on the inner peripheral side having a uniform thickness along the entire width of the permanent magnet 2 becomes a resistance to obstruct the flow of magnetic flux inside the rotor core 3, and the magnetic force of the permanent magnet 2 is weakened. , But not as much as the outer circumferential gap,
It is undeniable that the output and torque of the electric motor are reduced.

An object of the present invention is to solve such a problem.

[0008]

According to a first aspect of the present invention, there is provided a rotor provided with a gap inside a stator, and a permanent magnet inserted in a rotor core extending in a rotor axial direction provided in a rotor core of the rotor. In a rotating electric machine in which a magnet is inserted and fixed, an outer peripheral side surface of the permanent magnet is in close contact with the magnet insertion hole with respect to a rotation center of the rotor, and an inner peripheral side surface of the permanent magnet is along the magnet insertion hole. A cooling passage through which the refrigerant is guided is formed, and a cross-sectional shape of the cooling passage is formed to be a convex shape having an apex toward the rotation center.

According to a second aspect of the present invention, in the first aspect, the cooling passage has a substantially triangular cross section in which a maximum width of a base is part of an inner peripheral side surface of the permanent magnet.

[0010] In a third aspect based on the first aspect, the cooling passage has a substantially triangular cross section in which the maximum width of the base is the same as the inner peripheral side surface of the permanent magnet.

In a fourth aspect based on the first aspect, the cooling passage is formed by a plurality of grooves extending from the magnet insertion hole, and is configured to be substantially triangular when connecting the apexes of the grooves.

In a fifth aspect based on the first aspect, the cooling passage is opened at an end face of the rotor, and a part of the rotor is immersed in a refrigerant stored in an internal space of a case of the rotating electric machine. .

In a sixth aspect based on the fifth aspect, a member for stirring the refrigerant is provided near the opening of the cooling passage on a side surface of the rotor.

According to a seventh aspect of the present invention, in the first aspect, a passage for guiding the refrigerant to the rotating shaft of the rotor is formed through the passage, the passage is connected to the cooling passage, and the refrigerant from the outside is guided to the cooling passage. To do.

According to an eighth aspect of the present invention, there is provided a rotating electric machine comprising a stator and a rotor, wherein a permanent magnet is inserted and fixed in a magnet insertion hole extending in a rotor axial direction provided in a rotor core of the rotor. A surface of the magnet on the stator side is in close contact with the magnet insertion hole, and a cooling passage through which the refrigerant is guided along the magnet insertion hole is formed on the opposite surface, and a cross-sectional shape of the cooling passage is defined by the permanent magnet. It is formed so as to have a convex shape having a vertex on the far side.

[0016]

According to the first aspect of the present invention, the inner peripheral surface of the permanent magnet can be directly cooled by the refrigerant to prevent the performance from being degraded due to the temperature rise of the permanent magnet, while being formed on the inner peripheral side of the permanent magnet. Since the cross-sectional shape of the cooling passage to be formed is convex toward the center of rotation, increasing the Lq / Ld ratio increases reluctance torque and reduces the decrease in magnet torque due to the provision of the cooling passage. By compensating, it is possible to suppress a decrease in overall output and torque as a rotating electric machine.

According to the second aspect of the present invention, the base of the cross section of the cooling passage is formed as a part of the inner peripheral side surface of the permanent magnet, so that the ratio Lq /
The Ld ratio can be increased, and the effect of suppressing reduction in output and torque can be increased accordingly.

According to the third aspect of the present invention, the permanent magnet can be efficiently cooled by matching the cross-section base of the cooling passage with the entire width of the permanent magnet.

According to the fourth aspect of the invention, by forming the cooling passage with a plurality of grooves, the Lq / Ld ratio can be increased as described above.

In the fifth aspect, since the rotor is immersed in the refrigerant, the refrigerant can easily flow through the cooling passage, and the configuration of the cooling system can be simplified.

In the sixth aspect, the refrigerant is stirred by the rotation of the rotor, and the refrigerant can be efficiently guided to the cooling passage.

According to the seventh aspect of the present invention, the refrigerant does not flow inside the rotor and does not leak to the outside. Therefore, efficient cooling is possible, and there is no rotational resistance of the rotor, and the mechanical efficiency is reduced. Nothing.

According to the eighth aspect, the same function and effect as those of the first aspect are obtained even with a rotating electric machine in which a rotor is disposed outside the stator.

[0024]

Embodiments of the present invention applied to a synchronous motor will be described below with reference to the drawings.

In the first embodiment shown in FIG. 1, only the rotor 11 of the electric motor is shown in this figure, and the stator arranged on the outer peripheral side of the rotor 11 is omitted.

A plurality of permanent magnets 12 are arranged on a rotor core 13 constituting the rotor 11 at equal intervals on the same circumference around a rotation shaft 14. In this example, eight permanent magnets 12 are arranged such that adjacent magnetic poles are different from each other.

The permanent magnet 12 is provided on the rotor core 13.
It is inserted and fixed in a magnet insertion hole 16 extending in the axial direction of the rotor.

Here, the cross-sectional shape of the magnet insertion hole 16 is the same as the outer surface of the permanent magnet 12 so as to be in close contact with the outer surface of the permanent magnet 12 around the rotary shaft 14.
The inner circumferential side of the cooling passage 15
A substantially triangular mountain-shaped inclined surface 16b protruding toward the rotating shaft 14 is formed such that

That is, the cross section of the cooling passage 15 is formed in a triangular shape whose base is smaller than the circumferential width of the permanent magnet 12 and whose top is directed toward the axis of the rotating shaft 14.

By forming the cooling passage 15 in this manner, the Lq / Ld ratio of the rotor 11, that is, the ratio between the inductance (Lq) in the q-axis direction of the rotor and the inductance (Ld) in the d-axis direction is increased. Can be a permanent magnet 12
Due to the gap formed by the cooling passage 15 provided on the inner peripheral side of the motor, even if the torque by the permanent magnet 12 decreases, the reluctance torque increases, so that the output and torque of the electric motor can be prevented from lowering.

The permanent magnet 12 is fixed by inserting it into the magnet insertion hole 16 with the adhesive applied, but at this time, the adhesive is not applied to the surface of the cooling passage 15 which contacts the refrigerant, and the cooling efficiency is reduced. To prevent the decline.

In this case, since the cooling passage 15 is provided on the inner peripheral side of the permanent magnet 12, the permanent magnet 12 coated with the adhesive on the outer peripheral surface side is inserted into the magnet insertion hole 16, and then the jig is inserted into the cooling passage 15. For example, the permanent magnet 12 can be strongly pressed toward the outer peripheral side by inserting the adhesive into the outer periphery, and if the adhesive is solidified in this state, the adhesive layer can be made extremely thin. Since this adhesive layer is equivalent to an air gap in terms of a magnetic circuit, the rotor 11
If there is a gap on the outer peripheral side of the magnet, the gap becomes a large resistance to the flow of the magnetic flux from the permanent magnet 2 to the stator, which causes a decrease in the output and torque of the electric motor. Such a problem can be avoided as much as possible.

As the motor rotates, the temperature of the permanent magnet 12 of the rotor 11 rises due to self-heating caused by an eddy current flowing in the permanent magnet and heat transfer caused by heating of the stator winding.
If the temperature rise causes the magnetic force to weaken and the output and torque of the motor decrease, or if the temperature causes permanent demagnetization, the initial performance may not be maintained.

However, the cooling passage 15 is formed on the inner peripheral side of the permanent magnet 12 as described above, and the permanent magnet 12 can be efficiently cooled by flowing a coolant such as insulating oil through the cooling passage 15. The temperature rise can be effectively suppressed. Note that the supply of the refrigerant to the cooling passage 15 is specifically performed by a method described later with reference to FIGS.

Next, the embodiment shown in FIG. 2 will be described.

This is because the base of the cooling passage 15 is
Of the refrigerant in the circumferential direction, the contact area of the refrigerant with the permanent magnet 12 is increased, and the cooling efficiency of the permanent magnet 12 is further increased.

The angled slope 16 of the magnet insertion hole 16
For b, the inclination angle is set smaller than that in FIG.

In the embodiment shown in FIG. 3, a plurality of grooves 16c having different depths are provided parallel to each other from the magnet insertion hole 16 on the inner peripheral side of the permanent magnet 12, and the apex of each groove 16c is connected to form a mountain shape. The grooves 16
The cooling passage 15 is formed by c.

In this case, by forming the cooling passage 15 with the plurality of grooves 16c, the above-described Lq / Ld ratio can be further increased, and a decrease in the output torque can be suppressed accordingly. . Further, since the permanent magnet 12 is also supported on the inner peripheral side of the magnet insertion hole 16, the holding of the permanent magnet 12 becomes more reliable.

Further, the embodiment shown in FIG. 4 will be described.

FIG. 4 is an overall sectional view of the electric motor. End plates 21 are arranged on both sides of the rotor 11 in the axial direction. The end plates 21 are fixed to the rotating shaft 14 by welding or the like. In a state of being compressed and held, the rotating torque generated in the rotor 11 is transmitted from the rotor core 13 to the end plate 21 by mutual contact frictional force,
Further, the power is transmitted to the rotation shaft 14.

The rotating shaft 14 of the rotor 11 is rotatably supported by the case 20 via a bearing (not shown) disposed at a penetrating portion thereof. A stator 17 is arranged on the outer peripheral side of the rotor 11 with a predetermined gap.
Is fixedly supported on the inner surface of the case 20 with the coil 18 wound.

The interior of the case 20 basically includes the rotor 1
1. Except for the stator 17, a closed internal space 23 is formed, and a refrigerant is supplied to the internal space 23 from an inlet 24a provided above one side surface of the case 20. Outlet 2 provided below the other side of the
4b.

The end plate 21 is provided with a through hole 22 at a position corresponding to the cooling passage 15 of the permanent magnet 12 provided in the rotor 11, whereby the cooling passage 15 is connected to the outside of the rotor 11. .

In the internal space 23 of the case 20, the supply amount of the refrigerant is adjusted so that a predetermined amount of the refrigerant is always stored.
The stored refrigerant is guided through the through-hole 22 of the end plate 21 to cool the permanent magnet 12.

In this case, in particular, since a part of the rotor 11 is immersed in the refrigerant, the cooling of the rotor core 13 together with the permanent magnet 12 can be performed effectively.

The embodiment shown in FIG. 5 differs from the embodiment shown in FIG.
The fin 2 is provided near the outside of the through hole 22 and on the rear side in the rotational direction.
5 is provided so that the refrigerant stored in the internal space 23 is actively scraped by the fins 25 when the rotor 11 rotates, so that the flow of the refrigerant to the cooling passage 15 is improved.

This makes it possible to cool the permanent magnet 12 more efficiently.

[0049] Instead of providing the fins 25 on the end plate 21, a part of the end plate 21 may be shaved to provide an equivalent stirring effect. Further, the refrigerant may be circulated through the cooling passage 15 by other means such as a pump, a screw, and an impeller.

Next, the embodiment shown in FIG. 6 will be described. In this embodiment, a passage for guiding the refrigerant to the cooling passage 15 is formed inside the rotary shaft 14, and the internal space 23 of the case 20 is simply a passage through which the refrigerant does not flow. It is a space.

For this reason, an upstream passage 26 a and a downstream passage 26 b are formed in the axis of the rotary shaft 14, and the end plate 2 is connected to these two ends of the cooling passage 15.
1 are each formed with a branch passage 26c extending in the radial direction.

The refrigerant introduced from the upstream passage 26a is
It flows into one end of the cooling passage 15 through the branch passage 26c,
It flows to the downstream side while cooling the permanent magnet 12, and then flows out from the branch passage 26c to the downstream passage 26b.

In this case, since there is no refrigerant in the internal space 23 and no friction torque is generated by the refrigerant between the rotor 11 and the stator 17, the mechanical loss of the rotor 11 is reduced accordingly. Further, since the cooling system including the cooling passage 15 has a closed circuit, the design for cooling the permanent magnet 12 is facilitated.

In the above embodiment, an example in which the present invention is applied to a motor is shown. However, it is apparent that the present invention can be similarly applied to a generator. Further, the cross section of the permanent magnet is not limited to a rectangle, but may be an arc shape, a kamaboko shape, or the like.

The present invention is also applicable to a rotating electric machine in which a cylindrical rotor is concentrically arranged outside the stator.

The present invention is not limited to the above-described embodiment, but includes various changes and improvements that can be made by those skilled in the art within the scope of the technical idea of the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a part of a rotor according to a second embodiment.

FIG. 3 is a sectional view showing a part of a rotor according to a third embodiment.

FIG. 4 is a cross-sectional view of an electric motor according to a fourth embodiment.

FIG. 5 is a rotor side view of a fifth embodiment.

FIG. 6 is a sectional view of an electric motor according to a sixth embodiment.

FIG. 7 is a partial cross-sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotor 12 Permanent magnet 13 Rotor iron core 14 Rotation axis 15 Cooling passage 16 Magnet insertion hole 16a Plane 16b Inclined surface

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) // H02K 1/32 H02K 1/32 Z (72) Inventor Toshio Kikuchi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Automobile Stock In-house (72) Inventor Takashi Tsuneyoshi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term (reference) 5H002 AA10 AB08 AD04 AE00 5H609 BB03 BB19 BB21 PP07 QQ14 RR06 RR36 RR42 RR69 RR73 5H621 BB07 HH01 AK11 5H CA02 CA07 CA10 CB01 PP10 PP19

Claims (8)

[Claims] 1. A rotating electric machine comprising a rotor arranged inside a stator with a gap, and a permanent magnet inserted and fixed in a magnet insertion hole extending in a rotor axial direction provided in a rotor core of the rotor. An outer peripheral side surface of the permanent magnet is in close contact with the magnet insertion hole with respect to a rotation center of the rotor, and a cooling passage through which a refrigerant is guided along the magnet insertion hole is formed on an inner peripheral side surface of the permanent magnet. The rotating electric machine is characterized in that the cross-sectional shape of the cooling passage is formed to be a convex shape having an apex toward the rotation center. 2. The rotating electric machine according to claim 1, wherein said cooling passage has a substantially triangular cross section in which a maximum width of a base portion is part of an inner peripheral side surface of the permanent magnet. 3. The rotating electric machine according to claim 1, wherein the cooling passage has a substantially triangular cross section in which a maximum width of a base is the same as an inner peripheral side surface of the permanent magnet. 4. The rotating electric machine according to claim 1, wherein the cooling passage is formed by a plurality of grooves extending from the magnet insertion holes, and is configured to be substantially triangular when connecting the vertexes of the grooves. 5. The rotating electric machine according to claim 1, wherein the cooling passage is opened at an end face of the rotor, and a part of the rotor is immersed in a refrigerant stored in an internal space of a case of the rotating electric machine. 6. The rotating electric machine according to claim 5, wherein a member for stirring the refrigerant is provided on a side surface of the rotor near an opening of the cooling passage. 7. The rotation according to claim 1, wherein a passage for guiding the refrigerant to the rotating shaft of the rotor is formed through the passage, and this passage is connected to the cooling passage, and the refrigerant from the outside is guided to the cooling passage. Electric machine. 8. A rotary electric machine comprising a stator and a rotor, wherein a permanent magnet is inserted and fixed in a magnet insertion hole extending in a rotor axial direction provided in a rotor core of the rotor. The surface on the side is in close contact with the magnet insertion hole, and a cooling passage through which the refrigerant is guided along the magnet insertion hole is formed on the opposite surface, and the cross-sectional shape of the cooling passage is apex far away from the permanent magnet. A rotating electric machine formed to have a convex shape having