WO2016002253A1

WO2016002253A1 - Dynamo-electric machine

Info

Publication number: WO2016002253A1
Application number: PCT/JP2015/055509
Authority: WO
Inventors: 道年東; 森　剛; 盛幸枦山; 大穀　晃裕; 知也立花; 秀哲有田
Original assignee: 三菱電機株式会社
Priority date: 2014-07-02
Filing date: 2015-02-26
Publication date: 2016-01-07
Also published as: JP6173593B2; JPWO2016002867A1; WO2016002867A1

Abstract

Provided is a dynamo-electric machine with which it is possible to evenly distribute heat in the central axial direction of a rotor and suppress thermal demagnetization of a permanent magnet without increasing the size of the dynamo-electric machine. The dynamo-electric machine (1) is characterized in that: provided are a stator (31) having a stator core (32) and a multilayer winding (33) wound around the stator core (32), and a rotor (40) having a rotor core disposed facing the stator core (32), the rotor (40) being supported so as to be capable of rotating relative to the stator (31); the rotor core has a permanent magnet (42) as well as a first cooling flow path (134), a second cooling flow path (135), and a third cooling flow path (136) that pass through in the central axial direction of the rotor (40) and are lined up in the stated order in the central axial direction of the rotor (40); and the cross-sectional area of the second cooling flow path (135) that is perpendicular to the central axial direction of the rotor (40) is less than the cross-sectional area of the first cooling flow path (134) and the cross-sectional area of the third cooling flow path (136).

Description

Rotating electric machine

The present invention relates to a rotating electrical machine including a rotor having permanent magnets.

Rotating electrical machines for driving and generating electric vehicles or hybrid vehicles are required to be highly efficient and downsized. Therefore, in recent years, permanent magnet type rotating electrical machines are generally used as rotating electrical machines for electric vehicles or hybrid vehicles. In order to improve the rotational torque in a permanent magnet type rotating electrical machine, a permanent magnet having a large maximum energy product is desired. Therefore, there are many cases where neodymium magnets having a large maximum energy product are used as permanent magnets used in rotating electrical machines. In automobile applications, the rotating electrical machine may be disposed near the engine. The rotating electrical machine in this case is required to be driven at a high temperature. Furthermore, when a permanent magnet type rotating electrical machine is energized, it is caused by Joule loss caused by excitation of multiphase windings in the stator, iron loss caused by an alternating magnetic field, and eddy current loss caused by interlinkage magnetic flux to the magnet. The rotating electrical machine generates heat. In order to suppress the self-heating of the rotating electrical machine, it is necessary to cool the rotating electrical machine.

As the cooling method, for example, in the rotating electric machine of Patent Document 1, a cooling flow path through which the refrigerant passes in the rotating shaft of the rotor is provided in order to cool the rotor.

Further, in the rotating electrical machine of Patent Document 2, a flow path along the radial direction from the central axis of the rotor is formed in the rotor core.

Furthermore, in the rotating electrical machine of Patent Document 3, a plurality of protrusions are formed on the inner peripheral surface of the cooling flow path in the rotor core.

JP2009-081953 JP2011-097725 JP2012-165600

In the configuration using the cooling flow path in Patent Document 1, the central portion in the central axis direction of the rotor core is actively cooled. However, in order to pass a sufficient amount of refrigerant through the cooling flow path in the rotating shaft, it is necessary to increase the cross-sectional area of the cooling flow path, and there is a problem that the rotating shaft is enlarged.

Also, with the configuration of Patent Document 2, the cooling performance of the central portion in the central axis direction of the rotor is improved. However, since the cooling flow path is provided in the radial direction of the rotor, the length of the rotor core in the central axis direction increases, and there is a problem that the rotor is enlarged in the central axis direction.

Furthermore, in the configuration of Patent Document 3, since the cooling area is increased by a plurality of protrusions on the inner peripheral surface of the cooling flow path, the rotor cooling performance is improved without increasing the size of the rotor. However, the cross-sectional shape perpendicular to the central axis of the rotor in the cooling channel is the same shape in the direction of the central axis of the rotor. For this reason, the cooling performance of the central portion in the central axis direction is the same as that of the end portion in the central axial direction of the rotor. Therefore, there is a problem that the temperature difference between the end portion in the central axis direction of the rotor and the central portion in the central axis direction is not flattened, and the heat distribution in the central axis direction of the rotor is not uniformed.

The present invention has been made in order to solve the above-described problems, and can achieve uniform heat distribution in the direction of the central axis of the rotor without increasing the size of the rotating electrical machine. A rotating electrical machine capable of suppressing magnetism is obtained.

A rotating electrical machine according to the present invention includes a stator core and a stator having a multi-layer winding wound around the stator core, and a rotor core disposed so as to face the stator core. A rotor core rotatably supported, and the rotor core includes a permanent magnet, a first cooling flow path, a second cooling channel, and a second cooling passage arranged in order in the direction of the center axis of the rotor. The cross-sectional area of the second cooling flow path that has the cooling flow path and the third cooling flow path and is perpendicular to the central axis direction of the rotor is the cross-sectional area of the first cooling flow path and the third cooling flow. It is characterized by being smaller than the cross-sectional area of the road.

According to the rotating electrical machine according to the present invention, the cross-sectional area of the second cooling channel perpendicular to the central axis direction of the rotor is greater than the cross-sectional area of the first cooling channel and the third cooling channel. Therefore, the flow rate of the refrigerant in the second cooling channel is increased, and the cooling effect at the central portion in the central axis direction of the rotor having a high temperature is improved as compared with the cooling effects at both ends in the central axial direction. Therefore, it is possible to change the cooling performance distribution from the both ends of the central axis direction where the temperature is relatively low to the central part where the temperature is high, and the heat distribution in the central axis direction of the rotor without increasing the size of the rotating electrical machine. Can be made uniform. In addition, the permanent magnet can be efficiently cooled and thermal demagnetization of the permanent magnet can be suppressed.

It is a sectional side view of the upper half surface of the rotary electric machine which concerns on Embodiment 1 for implementing this invention. It is a perspective view of the rotor core which concerns on Embodiment 1 of this invention. It is principal part sectional drawing of the rotor which concerns on Embodiment 1 of this invention. It is principal part sectional drawing of the rotor which concerns on Embodiment 1 of this invention. It is a characteristic figure of the thermal conductance of the rotor concerning Embodiment 1 of the present invention. It is a temperature characteristic figure of the rotor which concerns on Embodiment 1 of this invention. It is a figure which shows the cooling effect of the cooling flow path in the rotor which concerns on Embodiment 1 of this invention. It is sectional drawing of the rotor core which concerns on Embodiment 2 of this invention. It is sectional drawing of the 2nd cooling flow path 135a in the rotor core which concerns on Embodiment 3 of this invention. It is sectional drawing of the 2nd cooling flow path 135b in the rotor core which concerns on Embodiment 4 of this invention. It is a perspective view of the rotor which concerns on Embodiment 5 of this invention. It is a sectional side view which comprises the principal part of the rotor core which concerns on Embodiment 5 of this invention. It is a sectional side view which comprises the principal part of the rotor core which concerns on Embodiment 6 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a side sectional view of an upper half surface of a rotating electrical machine 1 according to Embodiment 1 for carrying out the present invention. In FIG. 1, the rotating electrical machine 1 includes an annular stator 31 and a rotor 40 that is disposed inside the stator 31 and is rotatable with respect to the stator 31.

The stator 31 includes a stator core 32 and a multiphase winding 33 wound around the stator core 32, and the outer periphery of the stator core 32 is fixed to the frame 10. The stator core 32 is configured by laminating and integrating a plurality of magnetic steel plates formed in a predetermined shape in the central axis direction of the rotor 40. Further, the stator core 32 protrudes in a radial direction that is a direction perpendicular to the central axis of the rotor 40 from the cylindrical core back and the inner peripheral surface of the core back, and is arranged in 48 pieces at an equiangular pitch in the circumferential direction. The teeth are provided. In FIG. 1, the teeth and the core back are omitted. Here, the stator has multiphase windings 33 wound around the teeth so that the number of teeth per phase per phase is 2, but the detailed winding distribution is omitted in FIG. Has been.

The rotor 40 includes a permanent magnet 42 (not shown) as a magnetomotive force generation source, a first rotor core 34, a second rotor core 35, a third rotor core 36, and a rotation shaft 38. Yes. Further, the rotor 40 is rotatably attached to the

brackets

11 and 12 attached to both ends of the rotor 40 in the central axis direction via bearings 39 attached to both ends of the rotary shaft 38 in the central axis direction. Yes. The first rotor core 34, the second rotor core 35, and the third rotor core 36 are fixed to the outer periphery of the rotating shaft 38. Further, the first rotor core 34, the second rotor core 35, and the third rotor core 36 are disposed so as to face the stator core 32.

In the first rotor core 34, the second rotor core 35, and the third rotor core 36, a first cooling flow path 134 that is a flow path through which a refrigerant such as air or oil passes, a second cooling flow A channel 135 and a third cooling channel 136 are formed. The bracket 11 is provided with a refrigerant inlet 13, and the bracket 12 is provided with a refrigerant outlet 14. Although not shown, at least one of the refrigerant inlet 13 and the refrigerant outlet 14 is attached with a fan or a pump that is a power source for moving the refrigerant. The fan or pump then passes through the first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136 in order from the refrigerant inlet 13 to the refrigerant outlet 14 in FIG. Move the refrigerant in the direction of the arrow. Note that the fan or pump is not limited to the refrigerant inlet 13 and the refrigerant outlet 14, and may be attached to the outside of the rotating electrical machine to move the refrigerant to the refrigerant inlet 13 and the refrigerant outlet 14.

FIG. 2 is a perspective view of the rotor core according to the present embodiment. In FIG. 2, the first rotor core 34, the second rotor core 35, and the third rotor core 36 are formed of a plurality of magnetic steel plates formed in a predetermined shape in the direction of the central axis of the rotor 40. Each is manufactured by being laminated and integrated. Permanent magnets 42 (not shown) are arranged on the first rotor core 34, the second rotor core 35, and the third rotor core 36 at equiangular pitches in the circumferential direction that is the rotation direction of the rotor 40. Permanent magnet insertion holes 41 are formed. Further, the hole 41-1 is formed adjacent to the permanent magnet 42 inserted through the permanent magnet insertion hole 41, and at a position that minimizes the width between the permanent magnet 42 and the outer periphery of the rotor core. The permanent magnet 42 is not inserted into the hole 41-1, and leakage of magnetic flux between the permanent magnets 42 can be suppressed.

The first rotor core 34, the second rotor core 35, and the third rotor core 36 have a first cooling channel 134, a second channel through which a refrigerant such as air or oil passes, A cooling channel 135 and a third cooling channel 136 are respectively formed. For simplification of the drawing, the end plate provided at the central axial direction end of the rotor core is not shown.

In FIG. 2, the first cooling channel 134, the second cooling channel 135, and the third cooling channel 136 are provided between the permanent magnet insertion holes 41 at an equiangular pitch in the circumferential direction. However, it is not necessary to have an equiangular pitch with respect to the circumferential direction. The number of the first cooling channel 134, the second cooling channel 135, and the third cooling channel 136 does not need to match the number of the permanent magnet insertion holes 41.

3 and 4 are cross-sectional views of the main part of the rotor according to the present embodiment. FIG. 3 shows a cross-sectional shape of the first cooling flow path 134 of the first rotor core 34 and a cross-sectional shape of the third cooling flow path 136 of the third rotor core 36. FIG. This is the cross-sectional shape of the second cooling flow path 135 of the rotor core 35. Here, the broken lines shown in FIG. 4 indicate the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136, and are compared with the cross-sectional shape of the second cooling flow path 135. For illustration. 3 and 4, the cross-sectional area perpendicular to the central axis direction of the rotor 40 in the second cooling flow path 135 is the center of the rotor 40 in the first cooling flow path 134 and the third cooling flow path 136. It is smaller than the cross-sectional area perpendicular to the axial direction. Then, the refrigerant flows from the first cooling channel 134 to the third cooling channel 136 via the second cooling channel 135. For this reason, the 1st cooling flow path 134, the 2nd cooling flow path 135, and the 3rd cooling flow path 136 have penetrated from the one end of the center axis direction of the rotor 40 to the other end. That is, the first cooling channel 134, the second cooling channel 135, and the third cooling channel 136 are arranged side by side in the direction of the central axis of the rotor 40. The first rotor core 34, the second rotor core 35, and the third rotor core 36 are also arranged in order in the central axis direction of the rotor 40.

Next, the cooling operation of the rotating electrical machine 1 will be described. FIG. 5 is a characteristic diagram of the thermal conductance of the rotor according to the present embodiment. The horizontal axis in FIG. 5 represents the reduction rate κ of the cross-sectional area of the cooling channel described later. The vertical axis in FIG. 5 represents the thermal conductance [W / ° C.] of the rotor core described later. Further, a bar graph 51 and a bar graph 52 in FIG. 5 indicate the thermal conductance Ga of the first rotor core 34 and the thermal conductance Gb of the second rotor core 35, respectively.

Here, the reduction rate κ of the cross-sectional area Sb of the second cooling flow path 135 of the second rotor core 35 with respect to the cross-sectional area Sa of the first cooling flow path 134 of the first rotor core 34 is expressed as κ = It is defined as (Sa−Sb) / (Sa). When κ = 0, the sectional area Sb of the second cooling channel 135 is equal to the sectional area Sa of the first cooling channel 134. When κ> 0, the sectional area Sb of the second cooling channel 135 is , It is smaller than the cross-sectional area Sa of the first cooling flow path 134 (Sb <Sa). The thermal conductance is defined as the ease of passing heat. When the amount of heat generated in the rotor core is Q and the temperature difference between the rotor core and the refrigerant is ΔT, the thermal conductance G between the rotor core and the refrigerant is expressed by G = Q / ΔT. Thermal conductance is also the reciprocal of thermal resistance. For this reason, when the thermal conductance is large, heat is easily transmitted, so the temperature of the rotor core is lowered. On the other hand, if the thermal conductance is small, it is difficult for heat to be transmitted, so the temperature of the rotor core rises.

5, when κ = 0, the cross-sectional area of the second cooling flow path 135 is equal to the cross-sectional area of the first cooling flow path 134. For this reason, the pressure loss of the refrigerant flowing through the first cooling flow path 134 and the second cooling flow path 135 does not change and is constant. The flow rate of the refrigerant flowing through the first cooling channel 134 and the second cooling channel 135 is also constant. Therefore, since the pressure loss of the refrigerant is constant and the flow rate of the refrigerant is also constant, the thermal conductance in the first rotor core 34 and the second rotor core 35 is constant at Ga = Gb.

In FIG. 5, when κ> 0, the thermal conductance Ga of the first rotor core 34 is reduced as compared with the case where κ = 0. On the other hand, the thermal conductance Gb of the second rotor core 35 is increased. Furthermore, the thermal conductance Gb of the second rotor core 35 is larger than the thermal conductance Ga of the first rotor core 34 (Ga <Gb). Therefore, the cooling performance of the second rotor core 35 is improved with respect to the cooling performance of the first rotor core 34.

This principle will be explained. First, when the cross-sectional area Sb of the second cooling flow path 135 decreases from the cross-sectional area Sa of the first cooling flow path 134, the flow rate of the refrigerant in the second cooling flow path 135 increases from the law of flow rate conservation. When the flow rate of the refrigerant in the second cooling channel 135 increases, the pressure loss increases according to the following equation.

In Equation (1), P is a pressure loss, ξ is a friction loss coefficient, L is a length of the cooling channel, De is an equivalent diameter that is a diameter when the cooling channel cross section is approximated by a circle, u is The flow velocity of the refrigerant, ρ is the density of the refrigerant, n is the number of parallel cooling channels, Re is the Reynolds number, d is the diameter of the cooling channel, ν is the kinematic viscosity coefficient of the refrigerant, S is the cross-sectional area of the cooling channel, fw Represents the circumference of the cross section of the cooling channel. In the formula (1), the subscripts a, b, and c of the first cooling channel 134, the second cooling channel 135, and the third cooling channel 136 are omitted. The same applies to the following equations.
As a precondition in FIG. 5, the pressure difference between the refrigerant inlet of the first cooling channel 134 and the refrigerant outlet of the third cooling channel 136 is constant. For this reason, the flow rate of the refrigerant in the first cooling channel 134 decreases due to an increase in pressure loss in the second cooling channel 135. As a result, the average flow rate of the refrigerant in the entire rotor is reduced.
Here, the relationship between the thermal conductance and the flow rate of the refrigerant is shown in the following equation.

In equation (2), G is the thermal conductance of the first, second or

third rotor core

34, 35 or 36, A is the heat transfer area, h is the heat transfer coefficient, Nu is the Nusselt number, and λ is the heat transfer Represents a rate.

Since the flow rate of the refrigerant in the first cooling flow path 134 decreases, the thermal conductance Ga of the first rotor core 34 decreases from the equation (2). Therefore, the cooling performance of the first rotor core 34 is lowered. On the other hand, since the flow rate of the refrigerant in the second cooling flow path 135 increases, the thermal conductance Gb of the second rotor core 35 increases from the equation (2), and the cooling performance of the second rotor core 35 increases. improves. Therefore, the thermal conductance Gb of the second rotor core 35 is larger than the thermal conductance Ga of the first rotor core 34 (Ga <Gb). For this reason, the cooling performance of the second rotor core 35 is improved as compared with the cooling performance of the first rotor core 34.
In FIG. 5, assuming that the refrigerant is air, ρ = 1.2 [kg / m ³ ], ν = 0.0000154 [m ² / s], Nu = 4.36, λ = 0.0261 [W / ( mK)].

Furthermore, in FIG. 5, when the cross-sectional area Sb of the second cooling flow path 135 decreases and increases to κ = 61%, the thermal conductance Ga of the first rotor core 34 decreases monotonously. On the other hand, the thermal conductance Gb of the second rotor core 35 increases to κ = 26% and then decreases. When κ> 26%, the pressure loss also increases, so the average flow rate of the refrigerant in the entire rotor also decreases. The decrease in the thermal conductance Gb of the second rotor core 35 due to the decrease in the average refrigerant flow velocity in the entire rotor is the second rotor core 35 due to the increase in the refrigerant flow velocity in the second rotor core 35. This exceeds the increase in the thermal conductance Gb. For this reason, the thermal conductance Gb of the second rotor core 35 decreases, and the cooling performance of the second rotor core 35 decreases. However, even when κ = 61%, the thermal conductance Gb of the second rotor core 35 is larger than the thermal conductance Ga of the first rotor core 34 (Ga <Gb). For this reason, the cooling performance of the second rotor core 35 is improved as compared with the cooling performance of the first rotor core 34.

Although not shown in FIG. 5, the sectional area Sc of the third cooling channel 136 of the third rotor core 36 is equal to the sectional area Sa of the first cooling channel 134 of the first rotor core 34. Even if they are different from each other (Sa ≠ Sc), if they are larger than the cross-sectional area Sb of the second cooling flow path 135 of the second rotor core 35 (Sb <Sc), as in the case of Sb <Sa described above. The thermal conductance Gb of the second rotor core 35 becomes larger than the thermal conductance Gc of the third rotor core 36 (Gc <Gb). Therefore, the cooling performance of the second rotor core 35 is improved more than the cooling performance of the third rotor core 36.

This principle will be explained. When the cross-sectional area Sc of the third cooling flow path 136 is larger than the cross-sectional area Sb of the second cooling flow path 135, the third cooling flow is determined from the flow rate conservation law as in the case of Sb <Sa described above. The flow rate of the refrigerant in the path 136 decreases. For this reason, the thermal conductance Gc of the third rotor core 36 decreases, and the cooling performance of the third rotor core 36 decreases.

FIG. 6 is a temperature characteristic diagram of the rotor according to the present embodiment. The horizontal axis in FIG. 6 represents the reduction rate κ of the cross-sectional area of the cooling channel. The vertical axis in FIG. 6 represents the temperature [° C.] of the rotor core. Moreover, the bar graph 61 and the bar graph 62 in FIG. 6 have shown the temperature of the 1st rotor core 34, and the temperature of the 2nd rotor core 35, respectively. Here, the cross-sectional area Sc of the third cooling flow path 136 of the third rotor core 36 is equal to the cross-sectional area Sa of the first cooling flow path 134 of the first rotor core 34 (Sa = Sc). . A calculation formula for the temperature rise δT [° C.] of the first, second or

third rotor core

34, 35 or 36 is shown below.

In Formula (3), Q [W] represents the amount of heat.
When κ = 0%, the temperature of the second rotor core 35 is higher than the temperature of the first rotor core 34. On the other hand, in the case of κ> 0%, the temperature of the second rotor core 35 is lowered as compared with κ = 0%. For this reason, κ exists such that the temperature of the first rotor core 34 is higher than the temperature of the second rotor core 35. When κ is further increased, the temperature of the second rotor core 35 is lower than the temperature of the first rotor core 34. This indicates that the cooling performance of the second rotor core 35 is improved as compared with the cooling performance of the first rotor core 34.

FIG. 7 is a diagram showing the cooling effect of the cooling flow path in the rotor according to the present embodiment. FIG. 7 shows the results of analysis under conditions where heat is not transferred at both ends of the rotor core in the central axis direction. The horizontal axis in FIG. 7 represents the reduction rate κ of the cross-sectional area of the cooling channel. The vertical axis in FIG. 7 represents the absolute value ΔT = | Tmax−Tmin | [° C. where the maximum temperature of the first rotor core 34 is Tmax and the minimum temperature of the second rotor core 35 is Tmin. ] Represents the analysis value. From FIG. 7, as κ increases from 0, ΔT decreases, and when κ = 0.05, ΔT becomes minimal. Further, when κ increases, the temperature of the second rotor core 35 decreases from the temperature of the first rotor core 34, and ΔT> 0. Therefore, the sectional area Sa of the first cooling channel 134 and the sectional area Sb of the second cooling channel 135 at which ΔT is minimized can be obtained from κ at which ΔT is minimized. In FIG. 7, when 0 <κ <0.15, ΔT is lower than when κ = 0. Further, when 0.02 <κ <0.1, ΔT is half or less than that when κ = 0. When κ = 0.05, ΔT is 0 and is minimal. Therefore, when κ = 0.05, the temperature of the first rotor core 34 and the temperature of the second rotor core 35 are the same.

In such a rotating electrical machine 1, the first rotor core 34, the second rotor core 35, and the third rotor core 36 penetrate in the direction of the central axis of the permanent magnet 42 and the rotor 40, and the rotor 40. The first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136, which are arranged side by side in the direction of the central axis of the rotor 40, are perpendicular to the direction of the central axis of the rotor 40. Since the sectional area Sb of the second cooling channel 135 is smaller than the sectional area Sa of the first cooling channel 134 and the sectional area Sc of the third cooling channel 136, the refrigerant in the second cooling channel 135 The cooling effect at the central portion in the central axis direction of the rotor 40 having a high temperature is improved more than the cooling effect at both ends in the central axial direction. Further, the cross-sectional area Sb of the second cooling flow path 135 perpendicular to the central axis direction of the rotor 40 is larger than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Due to the small configuration, the rotating electrical machine 1 is not increased in size. Therefore, the cooling performance distribution can be changed from the both ends in the central axis direction where the heat dissipation characteristics are good and the temperature is relatively low to the central part in the central axis direction where the heat dissipation characteristics are poor and the temperature is high, and the rotating electrical machine 1 is increased in size. In addition, the heat distribution in the central axis direction of the rotor 40 can be made uniform. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

In the rotating electrical machine 1 according to the present embodiment, the multiphase winding 33 is wound around the stator core 32 by the distributed winding method, but may be wound around the stator core 32 by the concentrated winding method. .

In the rotating electrical machine 1 according to the present embodiment, the number of poles and the number of slots are 8 poles and 48 slots, but are not limited to this, and may be 8 poles and 72 slots, for example.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view of a rotor core according to Embodiment 2 for carrying out the present invention. In FIG. 8, the configuration of the rotating electrical machine 1 according to the present embodiment is different from that of the first embodiment in the following points. The cross-sectional shape of the second cooling flow path 135 has a quadrilateral shape, similar to the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136. And each two sides in the four corners of the quadrilateral shape are smoothly connected in an arc shape. Further, the cross-sectional shape of the first cooling flow path 134, the cross-sectional shape of the second cooling flow path 135, and the cross-sectional shape of the third cooling flow path 136 are between the permanent magnets 42 arranged in the circumferential direction of the rotor 40. When the reference line 44 is a line connecting the intermediate point 43 in the circumferential direction (a point on the outer periphery of the rotor 40 in FIG. 3) and a point perpendicular to the axis of the rotor 40 from the intermediate point 43, the reference line 44. And the long side direction is a quadrilateral shape formed in parallel. Here, the current having the same phase as the induced voltage generated by the linkage of the field magnetic flux generated by the permanent magnet 42 to the multiphase winding 33 of the stator 31 is delayed by 90 degrees with respect to the q-axis current and the q-axis current. This current is called d-axis current. The q-axis magnetic path 81 shown in FIG. 8 is a magnetic path through which the magnetic flux generated by the magnetic field generated by the q-axis current passes. The direction of the q-axis magnetic path at the intermediate point 43 in the circumferential direction between the permanent magnets 42 is the reference. Along line 44. Therefore, the long side direction of the quadrilateral shape is along the q-axis magnetic path 81.

Thus, the q-axis magnetic path 81 is formed so as to pass between the permanent magnet 42 and the first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136. The increase in the magnetic resistance on the q-axis magnetic path 81 by the first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136 can be prevented. Therefore, the q-axis inductance Lq, which is a proportional coefficient between the q-axis current and the magnetic flux generated by the q-axis current, is equivalent to the case where no cooling flow path is provided. Further, Lq increases as compared with the case where the cross-sectional shape of the second cooling flow path 135 is a conventional circular shape. Here, the center of this circular shape is at the same position as the centroid of the quadrilateral shape in the cross section of the cooling channel 135 of the present embodiment. Therefore, Lq is larger than the d-axis inductance Ld, which is a proportional coefficient between the d-axis current and the magnetic flux generated by the d-axis current (Lq> Ld). For this reason, Lq−Ld, which is an index of saliency, increases. Therefore, the reluctance torque proportional to Lq−Ld is improved with respect to the cooling channel having the conventional circular cross-sectional shape.

Thus, the cross-sectional shapes of the first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136 are in the circumferential direction between the permanent magnets 42 arranged in the circumferential direction of the rotor 40. When the reference line 44 is a line connecting the intermediate point 43 and the point perpendicular to the axis of the rotor 40 from the intermediate point 43, the reference line 44 and the long side direction are formed in a quadrilateral shape. In addition, since the long side direction of the quadrilateral shape is along the q-axis magnetic path 81, the reluctance torque proportional to Lq-Ld is improved with respect to the conventional cooling flow path having a circular cross-sectional shape.

Further, the arrangement of the first cooling channel 134, the second cooling channel 135, and the third cooling channel 136 is not an equiangular pitch, or the first cooling channel 134, the second cooling channel 135 are arranged. Even when the number of the third cooling flow paths 136 is smaller than the number of poles of the rotor 40, the quadrilateral shape of the first cooling flow path 134, the second cooling flow path 135, and the third cooling flow path 136 is reduced. Since the long side direction is along the q-axis magnetic path 81, the reluctance torque is improved, and the size and weight can be reduced.

Embodiment 3 FIG.
FIG. 9 is a cross-sectional view of second cooling flow path 135a in the rotor core according to Embodiment 3 for carrying out the present invention. In FIG. 9, the configuration of the rotating electrical machine 1 according to the present embodiment is different from that of the second embodiment in the following points. The cross-sectional shape of the second cooling flow path 135a is a quadrilateral slit shape divided into right and left along the reference line 44. An iron core portion 45 parallel to the reference line 44 divides these slits 135a-1 and 135a-2 at the center. Further, although the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136 are not illustrated, the cross-sectional shape of the second cooling flow path 135a is a shape obtained by removing the core portion 45. is there. For this reason, the cross-sectional area of the second cooling flow path 135a is smaller than the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136 by the cross-sectional area of the iron core portion 45. Yes. At the four corners of the quadrilateral shape in the slits 135a-1 and 135a-2, the two sides are smoothly connected in an arc shape. The long side direction of the quadrilateral shape in the slits 135a-1 and 135a-2 is along the q-axis magnetic path (not shown).

As described above, in the present embodiment, the cross-sectional shape of the second cooling flow path 135a is a quadrilateral shape divided into the left and right with respect to the reference line 44, and thus the fluid passing through the second cooling flow path 135a. The area in contact with the molecules can be increased, and the cooling performance can be improved.

In addition, since the cross-sectional shape of the second cooling flow path 135a is a quadrilateral shape divided to the left and right with respect to the reference line 44, the second cooling flow path is perpendicular to the central axis direction of the rotor 40. The cross-sectional area Sb of 135a is smaller than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Therefore, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Also, the long side direction of the quadrilateral shape of the second cooling channel 135a is along the q-axis magnetic path (not shown). For this reason, as in the second embodiment, the reluctance torque is improved and the size and weight can be reduced.

In addition, the cross-sectional shape of the second cooling flow path 135a is not only a quadrilateral shape divided to the left and right with respect to the reference line 44, but also the cross-sectional shape of the first cooling flow path 134 and the third shape. The cross-sectional shape of the cooling flow path 136 may be a quadrilateral shape that is divided to the left and right with respect to the reference line 44. In this case, the cross-sectional area Sb of the second cooling flow path 135a perpendicular to the central axis direction of the rotor 40 is greater than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Needs to be smaller. Also with this configuration, it is possible to increase the area in contact with the fluid molecules passing through the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136, and the cooling performance can be further enhanced. Further, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Embodiment 4 FIG.
FIG. 10 is a cross-sectional view of second cooling flow path 135b in the rotor core according to the fourth embodiment for carrying out the present invention. In FIG. 10, the configuration of the rotating electrical machine 1 according to the present embodiment is different from that of the second embodiment in the following points. The inner surface of the second cooling channel 135 b has a plurality of protrusions 46. Although the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136 are not shown in the drawing, the cross-sectional shape of the second cooling flow path 135b is a shape obtained by removing the plurality of protrusions 46. For this reason, the cross-sectional area of the second cooling flow path 135b is smaller than the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136 by the plurality of protrusions 46. At the four corners of the quadrilateral shape, each two sides are smoothly connected in an arc shape. The long side direction of the quadrilateral shape is along a q-axis magnetic path (not shown).

As described above, in the present embodiment, the inner surface of the second cooling channel 135b has a plurality of protrusions 46, that is, a shape having a plurality of irregularities, and thus the heat radiation area of the inner surface of the second cooling channel 135b is reduced. The cooling performance can be increased. Furthermore, since the fluid molecules are agitated by the uneven shape of each inner surface, the cooling performance can be enhanced.

Further, since the inner surface of the second cooling channel 135b has a plurality of protrusions 46, that is, a shape having a plurality of irregularities, the cross-sectional area Sb of the second cooling channel 135b perpendicular to the central axis direction of the rotor 40 is obtained. Is smaller than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Therefore, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Also, the long side direction of the quadrilateral shape of the second cooling channel 135b is along the q-axis magnetic path (not shown). For this reason, as in the second embodiment, the reluctance torque is improved and the size and weight can be reduced.

In addition, the inner surface of the second cooling channel 135b has not only a plurality of protrusions 46, that is, a shape having a plurality of irregularities, but also the cross-sectional shape of the first cooling channel 134 and the third cooling channel 136. The inner surface may have a plurality of protrusions 46, that is, a shape having a plurality of irregularities. In this case, the cross-sectional area Sb of the second cooling flow path 135b perpendicular to the central axis direction of the rotor 40 is greater than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Needs to be smaller. Also with this configuration, it is possible to increase the area in contact with the fluid molecules passing through the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136, and the cooling performance can be further enhanced. Further, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Further, in addition to the inner surface of the second cooling channel 135b having a plurality of protrusions 46, that is, a shape having a plurality of irregularities, the second cooling channel 135b is similar to the third embodiment. The cross-sectional shape may be a quadrilateral shape divided to the left and right with respect to the reference line 44. Even with such a configuration, it is possible to increase the area in contact with the fluid molecules passing through the second cooling flow path 135b, and the cooling performance can be improved. In addition, the inner surface of the second cooling channel 135b has a plurality of protrusions 46, that is, a shape having a plurality of irregularities, and the cross-sectional shape of the second cooling channel 135b is divided into left and right with respect to the reference line 44. Therefore, the sectional area Sb of the second cooling channel 135b perpendicular to the central axis direction of the rotor 40 is equal to the sectional area Sa of the first cooling channel 134 and the third cooling channel. It is smaller than the cross-sectional area Sc of the flow path 136. Therefore, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

In addition to the fact that the cross-sectional shape of the first cooling channel 134 and the inner surface of the third cooling channel 136 have a plurality of protrusions 46, that is, a shape having a plurality of irregularities, the third embodiment. Similarly to the above, the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136 may be quadrilateral shapes divided on the left and right with respect to the reference line 44. In this case, the cross-sectional area Sb of the second cooling flow path 135b perpendicular to the central axis direction of the rotor 40 is greater than the cross-sectional area Sa of the first cooling flow path 134 and the cross-sectional area Sc of the third cooling flow path 136. Needs to be smaller. Also with this configuration, it is possible to increase the area in contact with the fluid molecules passing through the cross-sectional shape of the first cooling flow path 134 and the cross-sectional shape of the third cooling flow path 136, and the cooling performance can be further enhanced. Further, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Embodiment 5 FIG.
FIG. 11 is a perspective view of a rotor according to Embodiment 5 for carrying out the present invention. In FIG. 11, the configuration of the rotating electrical machine 1 according to the present embodiment is different from the first embodiment in the points described below. The rotor 40 includes a fourth rotor core 63 and a fifth rotor instead of the first rotor core 34, the second rotor core 35, and the third rotor core 36 of the first embodiment. An iron core 64 and a sixth rotor iron core 65 are provided.

FIG. 12 is a cross-sectional side view of the main part of the rotor core according to the present embodiment. In FIG. 12, the configuration of the rotating electrical machine 1 according to the present embodiment is different from that of the first embodiment in the points described below. The fifth cooling channel 164 of the fifth rotor core 64 is inclined with respect to the central axis direction of the rotor 40 toward the outer peripheral side from the upstream side to the downstream side of the refrigerant. The fourth cooling flow path 163 of the fourth rotor core 63 and the sixth cooling flow path 165 of the sixth rotor core 65 are formed substantially parallel to the central axis direction of the rotor 40. . The fourth cooling channel 163 and the sixth cooling channel 165 are connected to each other at the upstream end and the downstream end of the refrigerant in the fifth cooling channel 164, respectively. For this reason, the radial position of the sixth cooling channel 165 is on the outer peripheral side with respect to the radial position of the fourth cooling channel 163. Therefore, the radial position on the sixth rotor core 65 side in the fifth cooling channel 164 is on the outer peripheral side than the radial position on the fourth rotor core 63 side in the fifth cooling channel 164. . That is, the radial position of the downstream end in the direction in which the refrigerant flows in the fifth cooling channel is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows. The cross-sectional area of the fifth cooling channel 164 is smaller than the cross-sectional area of the fourth cooling channel 163 and the cross-sectional area of the sixth cooling channel 165.

The flow of the refrigerant when the rotor 40 actually rotates will be described. In FIG. 12, when the rotor 40 rotates around the central axis, a refrigerant such as air or oil flows from the fourth cooling channel 163 to the sixth cooling channel 165 through the fifth cooling channel 164. When the refrigerant passes through the fourth cooling flow path 163, the fourth cooling flow path 163 is formed substantially parallel to the central axis direction of the rotor 40, so that the centrifugal force generated by the rotation of the rotor 40 becomes constant. The flow rate of the refrigerant becomes constant. On the other hand, the flow of the refrigerant changes in the fifth cooling channel 164. That is, since the radial position of the fifth cooling channel 164 is directed toward the outer periphery as it goes from the upstream side to the downstream side of the refrigerant, the centrifugal force is different between the upstream end and the downstream end of the refrigerant in the fifth cooling channel 164. . For this reason, the refrigerant passing through the fifth cooling channel 164 is agitated due to the difference in centrifugal force between the upstream end and the downstream end, and the number of heat exchanges between the refrigerant molecules and the heat transfer surface in the fifth cooling channel 164. Will increase. As a result, heat transfer between the fifth rotor core 64 and the refrigerant is improved.

Thus, in the present embodiment, the radial position of the downstream end in the direction in which the refrigerant flows in the fifth cooling channel 164 is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows. The refrigerant molecules passing through the fifth cooling channel 164 are agitated due to the difference in centrifugal force between the upstream end and the downstream end, and the number of times of contact with the heat transfer surface increases. As a result, the cooling performance of the fifth rotor core 64 can be improved as compared with the first embodiment.

Also, the cross-sectional area of the fifth cooling channel 164 is smaller than the cross-sectional area of the fourth cooling channel 163 and the sixth cooling channel 165. Therefore, similarly to the first embodiment, the heat distribution in the central axis direction of the rotor 40 can be made uniform without increasing the size of the rotating electrical machine 1. Further, the permanent magnet 42 can be efficiently cooled, and thermal demagnetization of the permanent magnet 42 can be suppressed.

Embodiment 6
FIG. 13 is a side cross-sectional view that constitutes a main part of a rotor core according to Embodiment 6 for carrying out the present invention. In FIG. 13, the configuration of the rotating electrical machine 1 according to the present embodiment is different from that of the fifth embodiment in the following points. The fourth cooling flow path 163 of the fourth rotor core 63 and the sixth cooling flow path 165 of the sixth rotor core 65 move toward the outer peripheral side from the upstream side to the downstream side of the refrigerant. It is inclined with respect to the central axis direction. The fourth cooling channel 163 and the sixth cooling channel 165 are connected at the upstream end and the downstream end of the refrigerant in the fifth cooling channel 164 of the fifth rotor core 64. That is, the radial position at the downstream end in the direction in which the refrigerant flows in the fourth cooling flow path 163 is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows in the fourth cooling flow path 163. The radial position at the downstream end in the direction in which the refrigerant flows in the sixth cooling flow path 165 is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows in the sixth cooling flow path 165. The cross-sectional area of the fifth cooling channel 164 is smaller than the cross-sectional area of the fourth cooling channel 163 and the cross-sectional area of the sixth cooling channel 165.

Thus, in the present embodiment, the radial position at the downstream end in the direction in which the refrigerant flows in the fourth cooling flow path 163 is the radial position at the upstream end in the direction in which the refrigerant flows in the fourth cooling flow path 163. It is on the outer peripheral side. The radial position at the downstream end in the direction in which the refrigerant flows in the sixth cooling flow path 165 is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows in the sixth cooling flow path 165. For this reason, the refrigerant molecules passing through the fourth cooling channel 163 and the sixth cooling channel 165 are agitated due to the difference in centrifugal force between the upstream end and the downstream end, and the number of times of contact with the heat transfer surface increases. As a result, the cooling performance of the fourth rotor core 63 and the sixth rotor core 65, that is, the cooling performance at both ends in the central axis direction of the rotor 40 can be improved as compared with the fifth embodiment.

Further, the fourth cooling channel 163, the fifth cooling channel 164, and the sixth cooling channel 165 of the fifth and sixth embodiments have the same cross-sectional shape as the first cooling channel 134 of the third embodiment. Or the cross-sectional shapes of the second cooling channel 135a and the third cooling channel 136. Further, the cross-sectional shapes of the fourth cooling channel 163, the fifth cooling channel 164, and the sixth cooling channel 165 of the fifth and sixth embodiments are the same as those of the first cooling channel 134 of the fourth embodiment. Or the cross-sectional shapes of the second cooling channel 135b and the third cooling channel 136.

1 rotating electrical machine, 10 frame, 11, 12 bracket, 13 refrigerant inlet, 14 refrigerant outlet, 31 stator, 32 stator core, 33 multi-phase winding, 34 first rotor core, 35 second rotation Core, 36, 3rd rotor core, 38 rotary shaft, 39 bearing, 40 rotor, 41 permanent magnet insertion hole, 41-1 hole, 42 permanent magnet, 43 intermediate point, 44 reference line, 45 core part, 46 protrusions, 51 bar graph indicating the thermal conductance of the first rotor core, 52 bar graph indicating the thermal conductance of the second rotor core, 61 bar graph indicating the temperature of the first rotor core, 62 second rotor Bar graph showing temperature of iron core, 63 4th rotor core, 64 5th rotor core, 65 6th rotor core, 81 q-axis magnetic path, 134 1st Cooling channel, 135, 135a, 135b, second cooling channel, 135a-1, 135a-2 slit, 136, third cooling channel, 163, fourth cooling channel, 164, fifth cooling channel, 165th 6 cooling channels.

Claims

A stator having a stator core and a multi-layer winding wound around the stator core;
A rotor having a rotor core disposed so as to face the stator core and supported rotatably with respect to the stator;
The rotor core penetrates in the direction of the central axis of the permanent magnet and the rotor, and is arranged in order in the direction of the central axis of the rotor. The first cooling channel, the second cooling channel, and the third cooling channel And
A cross-sectional area of the second cooling flow path perpendicular to the central axis direction of the rotor is smaller than a cross-sectional area of the first cooling flow path and a cross-sectional area of the third cooling flow path. Rotating electric machine.
The rotating electrical machine according to claim 1, wherein a cross-sectional area of the first cooling flow path perpendicular to a central axis direction of the rotor is equal to a cross-sectional area of the third cooling flow path.
The cross-sectional area of the first cooling channel and the cross-sectional area of the third cooling channel perpendicular to the central axis direction of the rotor are Sa, and the cross-sectional area of the second cooling channel is Sb and Sa When the decrease rate of Sb is κ = (Sa−Sb) / (Sa),
The rotating electrical machine according to claim 2, wherein the κ has a relationship of 0 <κ <0.15.
The rotating electrical machine according to claim 3, wherein the κ has a relationship of 0.02 <κ <0.1.
The cross-sectional shape of the first cooling channel perpendicular to the central axis direction of the rotor, the cross-sectional shape of the second cooling channel, and the cross-sectional shape of the third cooling channel are the circumferential direction of the rotor When the reference line is a line connecting the intermediate point in the circumferential direction between the permanent magnets arranged on the point and a point perpendicular to the axis of the rotor from the intermediate point, the reference line and the long side direction are The rotating electrical machine according to any one of claims 1 to 4, wherein the rotating electrical machine has a quadrangular shape formed in parallel.
6. The cross-sectional shape of the second cooling flow path perpendicular to the central axis direction of the rotor is a quadrilateral shape divided into left and right with respect to the reference line. The rotating electrical machine according to any one of the above.
The rotating electrical machine according to any one of claims 1 to 6, wherein an inner surface of the second cooling channel has a shape having a plurality of irregularities.
The radial position at the downstream end in the direction in which the refrigerant flows in the second cooling channel is located on the outer peripheral side with respect to the radial position at the upstream end in the direction in which the refrigerant flows. The rotating electrical machine according to claim 1.
The radial position at the downstream end of the first cooling channel in the direction in which the refrigerant flows is on the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows in the first cooling channel,
The radial position at the downstream end of the third cooling flow path in the direction in which the refrigerant flows is closer to the outer peripheral side than the radial position at the upstream end in the direction in which the refrigerant flows in the third cooling flow path. The rotating electrical machine according to claim 8, wherein