JP7334450B2 - Rotors and electric motors with rotors - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor having insulating members and an electric motor having the rotor.

2. Description of the Related Art Among conventional electric motors, there is known an inner rotor type permanent magnet electric motor in which a rotor having permanent magnets is rotatably arranged inside a stator that generates a rotating magnetic field. This permanent magnet motor is used, for example, for rotating a blower fan mounted on an air conditioner.

When this permanent magnet motor is driven by a PWM type inverter that performs high-frequency switching, a potential difference (shaft voltage) is generated between the inner ring and the outer ring of the bearing. When this shaft voltage reaches the dielectric breakdown voltage of the oil film inside the bearing, a current flows inside the bearing, causing electrolytic corrosion in the bearing.

In order to prevent this electrolytic corrosion of the bearing, there is known a rotor in which an insulating portion is provided to increase the impedance (insulation performance) of the rotor (see, for example, Patent Document 1). This rotor includes an annular outer core, an inner core positioned on the inner diameter side of the outer core, an insulating member positioned between the outer core and the inner core, and a center of the inner core. It has a shaft fixed to a through-hole penetrating in the axial direction, and a permanent magnet fixed to the outer peripheral surface of the outer peripheral iron core.

The insulating member of the rotor functions as a connecting member that connects the outer core and the inner core, and is made of insulating resin, for example.

JP 2010-166689 A

In such a rotor, the insulating member functions as a connecting member that connects the outer core and the inner core, so it is necessary to efficiently transmit power from the outer core to the inner core. be. Therefore, for example, if the connecting member is made of a relatively soft insulating material (elastomer, etc.), increasing the width of the connecting member in the radial direction may reduce the power transmission efficiency. be.

On the other hand, if the width of the connecting member is reduced (reduced) in the radial direction, a sufficient distance cannot be secured between the outer core and the inner core. However, there is a problem that it is difficult to suppress the electrolytic corrosion of the bearing.

Accordingly, the present invention provides a rotor capable of transmitting power from an outer core to an inner core without waste while suppressing electrolytic corrosion of the bearing by increasing the impedance of the rotor, and the rotor. The purpose is to provide electric motors and blowers.

In order to solve the above problems, one aspect of the rotor of the present invention includes an outer core, an inner core, and an insulating connecting member that connects the outer core and the inner core. . A plurality of annularly arranged grooves are formed in the connecting member. The outer core is formed with a plurality of inner peripheral recesses that are recessed from the inner peripheral surface in the outer diameter direction. The inner peripheral iron core is formed with a plurality of outer peripheral protrusions recessed in the radial direction from the outer peripheral surface thereof. The groove portion of the connecting member is arranged at a position on the inner diameter side with respect to the inner peripheral surface of the outer peripheral side core and on the outer diameter side with respect to the outer peripheral surface of the inner peripheral side core.

One aspect of the electric motor of the present invention includes a stator fixed to the motor shell, and the above-described rotor arranged on the inner diameter side of the stator. The rotor includes an annular outer core to which permanent magnets are fixed, an inner core positioned on the inner diameter side of the outer core, and an insulating connecting member positioned between the outer core and the inner core. and a shaft connected to the inner peripheral iron core and rotatably supported by a bearing on the outer shell of the motor.
One aspect of the blower of the present invention includes the electric motor described above.

According to the present invention, the impedance of the rotor can be increased, and power can be efficiently transmitted from the outer core to the inner core.

1 is a longitudinal sectional view showing a permanent magnet motor according to the present invention; FIG. FIG. 3A is a perspective view (a) and a plan view of an outer core in the rotor of the permanent magnet motor according to the present invention; FIG. 4A is a perspective view (a) and a plan view (b) of an inner peripheral iron core in the rotor of the permanent magnet motor according to the present invention; FIG. 4 is a perspective view of an insulating member in the rotor of the permanent magnet motor according to the present invention; 1 is a perspective view of a rotor of a permanent magnet motor according to the present invention; FIG. 6 is a plan view of the rotor of FIG. 5; FIG. FIG. 7 is a cross-sectional view taken along the line AA of FIG. 6; FIG. 8 is a cross-sectional view taken along line CC of FIG. 7; FIG. 8 is a cross-sectional view taken along line DD of FIG. 7; 1 is a perspective view of a rotor, a shaft and a second bearing of a permanent magnet motor according to the present invention; FIG. 1 is a cross-sectional view showing a permanent magnet motor according to the present invention; FIG. FIG. 11 is a perspective view showing how the permanent magnet motor of FIG. 1 or FIG. 10 is attached to an outdoor unit of an air conditioner;

An embodiment of the present invention will now be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and do not necessarily correspond to reality. Therefore, specific components should be determined with reference to the following description.

Further, the embodiments shown below are examples of apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the shape, structure, arrangement, etc. of the component parts. It is not specific to the following. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

An electric motor according to one embodiment of the present invention will be described below.

<Overall configuration of electric motor>
1 to 11 are diagrams for explaining the configuration of the electric motor 1 according to the first embodiment. As shown in these figures, this permanent magnet motor 1 is, for example, a brushless DC motor. This electric motor 1 is used to rotationally drive a blower fan mounted on an outdoor unit 10 of an air conditioner as shown in FIG. The outdoor unit 10 of the air conditioner includes, for example, a bottom plate 102 screwed to the base 101 of the outdoor unit 10, a top plate 103 fixed to the top of the outdoor unit 10, a pedestal 104 to which the electric motor 1 is attached, and a bottom plate. 102, an upper plate 103 and two pillars 105 to which a base 104 is fixed. The electric motor 1 is screwed to the central portion of the pedestal 104 .

In the following, an inner rotor type permanent magnet electric motor 1 in which a rotor 3 having permanent magnets 31 is rotatably arranged inside a stator 2 that generates a rotating magnetic field will be described as an example. A permanent magnet motor 1 in this embodiment includes a stator 2 , a rotor 3 , and a motor shell 6 .

<Stator and rotor>
The stator 2 includes a stator core 21 having a cylindrical yoke portion and a plurality of teeth extending radially from the yoke, and windings 23 wound around the teeth via insulators 22 . . The stator 2 is covered with a motor shell 6 made of resin except for the inner peripheral surface of the stator core 21 .

The rotor 3 is rotatably arranged on the inner peripheral side of the stator core 21 of the stator 2 with a predetermined gap. The rotor 3 is of a surface magnet type in which permanent magnets 31 are arranged annularly on the outer peripheral surface facing the stator core 21 . The permanent magnet 31 is fixed to the outer peripheral surface of the outer peripheral side iron core 32 which will be described later. The shaft 35 is connected to the inner peripheral iron core 34, and the power generated by the rotor 3 is transmitted to the load (blowing fan) via the shaft 35 to rotate the blowing fan. . Further, the shaft 35 is supported by the first bearing 41 and the second bearing 42 , and the rotor 3 is supported by the first bearing 41 being supported by the first bracket 51 and the second bearing 42 being supported by the second bracket 52 . is rotatably supported.

<Bearing and bracket>
The first bearing 41 supports one end side (output side) of the shaft 35 of the rotor 3 . The second bearing 42 supports the other end side (anti-output side) of the shaft 35 of the rotor 3 . Ball bearings, for example, are used for the first bearing 41 and the second bearing 42 .

The first bracket 51 is made of metal (steel plate, aluminum, etc.) and is arranged on one end side of the motor shell 6 , that is, on the output side of the shaft 35 . The first bracket 51 has a first bearing housing portion 511 for housing the first bearing 41 and a flange portion 512 extending from the open end of the first bearing housing portion 511 . The first bearing accommodating portion 511 is formed in a cylindrical shape having a bottom portion provided with a through hole for passing the shaft 35 , and the flange portion 512 of the first bracket 51 is insert-molded when the motor shell 6 is molded. , are integral with the motor shell 6 .

The outer ring of the first bearing 41 is press-fitted into the inner surface of the first bearing accommodating portion 511, and the output side of the shaft 35 supported by the inner ring of the first bearing 41 is formed in the center of the bottom of the first bearing accommodating portion 511. It protrudes outside from the through hole.

The second bracket 52 is made of metal (steel plate, aluminum, etc.) like the first bracket 51 , and is fixed to the other end side of the motor shell 6 , that is, to the counter-output side of the shaft 35 . The second bracket 52 is formed in a generally disk shape and includes an outer edge portion 520 that closes the end of the motor shell 6 on the opposite side of the output, and a second bearing accommodating portion 522 that accommodates the second bearing 42 . have. The second bracket 52 has an outer edge 520 screwed to the end of the motor shell 6 opposite to the output side.

The first bearing 41 is housed in a first bearing housing portion 511 provided in the first bracket 51 , and the second bearing 42 is housed in a second bearing housing portion 522 provided in the second bracket 52 . The first bearing 41 and the first bearing accommodating portion 511, and the second bearing 42 and the second bearing accommodating portion 522 are electrically connected.

The second bracket 52 may be integrally provided with a heat sink between the second bearing accommodating portion 522 and the outer edge portion 520 in a radial direction (hereinafter referred to as “radial direction”) about the central axis O (not shown). figure). As a result, space can be saved while improving the heat radiation performance of the electric motor 1 . Further, the second bracket may be provided with heat radiation fins (not shown) standing outward on the counter-output side of the shaft 35 as a heat sink. The second bracket may be in contact with a circuit board 72 (see FIG. 1) for controlling the electric motor 1 via a heat transfer member.

<Structure, action and effect of rotor according to the present invention>
Next, in the permanent magnet motor 1 according to the present embodiment, the structure of the rotor 3 according to the present invention and its action and effect will be described with reference to FIGS. 1 to 11. FIG.

In the permanent magnet motor 1 driven by a PWM type inverter, the neutral point potential of the windings does not become zero, and a voltage called common mode voltage is generated. The common mode voltage is generated on the inner ring side of the bearing (shaft side ) is divided as the potential of Also, the common mode voltage is determined by the electrostatic capacitance between the windings 23 of the stator 2 and the brackets (51, 52) and the electrostatic capacitance between the brackets (51, 52) and the circuit board 72 for driving the inverter. The potential is divided as the potential on the outer ring side (bracket side) of the bearings (41, 42). Due to this common mode voltage, a potential difference (shaft voltage) is generated between the outer and inner rings of the first bearing 41 and the second bearing 42 due to the stray capacitance inside the permanent magnet motor 1 . When this shaft voltage reaches the dielectric breakdown voltage of the oil film inside the bearing, a current flows inside the bearing, causing electrolytic corrosion inside the bearing.
Therefore, in the permanent magnet motor 1 according to the present embodiment, in order to prevent electrolytic corrosion from occurring in the first bearing 41 and the second bearing 42, as shown in FIG. I have. A specific configuration of the rotor 3 will be described below.

As shown in FIGS. 1 to 11, the rotor 3 includes a permanent magnet 31, an outer core 32, an insulating member (connecting member) 33, and an inner core 34 from the outer diameter to the inner diameter. and a shaft 35 .

As shown in FIGS. 1, 10 and 11, the permanent magnet 31 has a plurality of (e.g., 8 or 10) permanent magnet pieces 311 arranged such that N poles and S poles appear alternately at equal intervals in the circumferential direction. and is formed into a ring. It should be noted that the permanent magnet 31 may be a plastic magnet that is annularly formed by solidifying magnet powder with resin.

The outer core 32 is formed in an annular shape as shown in FIG. 2, and is located on the inner diameter side of the permanent magnet 31 as shown in FIGS. The outer core 32 is recessed in the outer diameter direction from an inner peripheral surface 324 (see FIG. 2) of the outer core 32 in order to secure the function of preventing rotation with the insulating member 33, which will be described later. It has a plurality of (for example, four in the circumferential direction) inner peripheral recesses 321 extending in the direction of O (hereinafter referred to as the “axial direction”). In other words, the inner peripheral concave portion 321 functions as a key groove (a groove that prevents slippage between the rotating member) that prevents rotation of the insulating member 33 .
By providing this key groove (inner peripheral side recessed portion 321), the connection strength between the connected members (outer peripheral side iron core 32 and insulating member 33) is improved, and power transmission efficiency can be enhanced. Further, the outer core 32 is provided with a plurality of (for example, 10 in the circumferential direction) outer protrusions 322 that protrude from the outer peripheral surface to the outer diameter side in order to position the permanent magnets 31 .

As shown in FIG. 2 , the plurality of inner peripheral recesses 321 extend axially from the end surface of the outer peripheral core 32 and are arranged at equal intervals in the circumferential direction. In this embodiment, the inner circumferential recess 321 is partitioned vertically by a partition wall 323 arranged in the center in the axial direction. Therefore, two inner peripheral recesses 321 are arranged so as to extend from both ends of the outer peripheral iron core 32 . As a result, the outer core 32 has a partition wall 323 between the axially adjacent inner recesses 321 , and the partition wall 323 (first retaining portion) allows the insulating member 33 (connection) to the outer core 32 . member) can be prevented from coming off (in both axial directions).
In other words, the partition wall 323 functioning as a retaining portion is formed at a position axially overlapping the inner peripheral side recessed portion 321 . As a result, as shown in FIGS. 8 and 9, the retaining portion (partition wall 323) does not need to protrude from the inner peripheral surface of the outer peripheral core 32 in the radial direction. can be prevented from becoming smaller. Therefore, it is possible to secure the separation distance between the outer peripheral core 32 and the inner peripheral core 34 and increase the impedance of the rotor 3 .

The plurality of outer peripheral side projections 322 extend in the axial direction and are arranged at regular intervals in the circumferential direction. In addition, each outer protrusion 322 is arranged to extend from one end to the other end of the outer core 32 in the axial direction.

As shown in FIG. 3, the inner core 34 is formed in an annular shape, and is located on the inner diameter side of the outer core 32 as shown in FIGS. The inner peripheral core 34 is recessed in the radial direction from the outer peripheral surface 345 (see FIG. 3) of the inner peripheral core 34 and extends in the axial direction in order to secure the function of preventing rotation with the insulating member 33, which will be described later. A plurality of (for example, six in the circumferential direction) outer peripheral recesses 341 are provided. That is, the outer peripheral recess 341 functions as a key groove that prevents the insulating member 33 from rotating. By providing this keyway (outer peripheral recess 341), the strength of the connection between the members (the insulating member 33 and the inner peripheral iron core 34) is improved, and power transmission efficiency can be enhanced.

The plurality of outer peripheral recesses 341 extend in the axial direction and are arranged at equal intervals in the circumferential direction. In this embodiment, the outer peripheral recessed portion 341 is defined by a partition wall 344 (retaining portion) arranged in the center in the axial direction. Therefore, two outer peripheral recesses 341 are arranged so as to extend from both ends of the inner peripheral iron core 34 . As a result, the inner peripheral core 34 has partition walls 344 between the outer peripheral recesses 341 adjacent in the axial direction. (connecting member) can be prevented from coming off (in both axial directions).
In other words, the partition wall 344 that functions as a retaining portion is formed at a position that axially overlaps with the outer peripheral side recessed portion 341 . As a result, as shown in FIGS. 8 and 9, the retaining portion (partition wall 344) does not need to protrude from the outer peripheral surface 345 of the inner peripheral side iron core 34 in the outer diameter direction. It is possible to prevent the distance between the iron cores 34 from becoming small. Therefore, the distance between the outer core 32 and the inner core 34 can be secured, and the impedance of the rotor 3 can be increased.

A through-hole 343 is provided at the center of the inner peripheral core 34 so as to extend therethrough in the axial direction. The shaft 35 is passed through the through hole 343 of the inner peripheral core 34, and the shaft 35 and the inner peripheral core 34 are connected. In addition, the inner peripheral core 34 may be provided with a plurality of through holes 342 for weight reduction between the through holes 343 and the outer peripheral surface 345 of the inner peripheral core 34 . These through-holes 342 are arranged at equal intervals in the circumferential direction so that the inner peripheral core 34 in which the through-holes 342 are formed has a spoke-like shape when viewed from the axial direction.

Further, as shown in FIG. 3, the plurality of through holes 342 formed in the inner peripheral core 34 are arranged at positions that do not radially overlap with the outer peripheral recesses 341 described above. Therefore, the through hole 342 and the outer recessed portion 341 do not come close to each other, so that the strength of the inner peripheral core 34 is prevented from being lowered.

As shown in FIGS. 4 to 9, the insulating member 33 (connecting member) has a cylindrical shape and connects the outer core 32 and the inner core 34 . That is, the outer core 32 and the inner core 34 are connected via an insulating member 33 (connecting member), and the insulating member 33 functions to transmit power between the outer core and the inner core. have The insulating member 33 is made of an elastomer (rubber elastic body) containing polypropylene (PP), ethylene propylene rubber (EPDM), or the like. In this embodiment, the insulating member 33 is formed integrally with the outer core 32 and the inner core 34 by filling an elastomer between the outer core 32 and the inner core 34 . In addition, the insulating member 33 may be formed only of an insulating resin.

The insulating member 33 (connecting member) is configured to increase the impedance between the outer core 32 and the inner core 34, although the details will be described later. In other words, the structure reduces the capacitance between the outer core 32 and the inner core 34 (part of the capacitance between the windings 23 of the stator 2 and the shaft 35). Thus, by reducing the potential difference between the inner ring side and the outer ring side of the first bearing 41 and the second bearing 42, it is possible to suppress the occurrence of electrolytic corrosion of the bearings.

As shown in FIG. 4 , the insulating member 33 has, on its outer peripheral surface, a plurality of outer protrusions 338 that engage with the inner recesses 321 of the outer core 32 described above. Also, the insulating member 33 has, on its inner peripheral surface, a plurality of inner peripheral protrusions 339 that engage with the outer peripheral recesses 341 of the inner peripheral iron core 34 .

That is, the inner recess 321 of the outer core 32 and the outer protrusion 338 of the insulating member 33 function as a first engaging portion that prevents rotation between the outer core 32 and the insulating member 33 , and the insulating member 33 The inner protrusion 339 and the outer recess 341 of the inner core 34 function as a second engaging part that prevents rotation between the insulating member 33 and the inner core 34 .

In this embodiment, the concave portion of the first engaging portion is provided on the outer peripheral core 32 side, and the concave portion of the second engaging portion is provided on the inner peripheral core 34 . 2, 3 and 8 when providing the engaging portion for preventing rotation between the rotor core (outer core 32, inner core 34) and the connecting member (insulating member 33). , by providing the concave portion of the engaging portion on the core (outer peripheral side core 32, inner peripheral side core 34) side, the convex portion of the engaging portion is provided on the core (outer peripheral side core 32, inner peripheral side core 34) The distance between the outer core 32 and the inner core 34 (the distance between the closest points) can be increased compared to the case where they are provided on the sides, and the impedance of the rotor 3 can be further increased.

Also, as shown in FIGS. 2 to 4 and FIGS. 8 and 9, the first engaging portions (321, 338) are arranged between the outer peripheral protrusions 338 (inner peripheral recesses 321) adjacent in the axial direction. A retaining portion (partition wall 323) is positioned between them. Similarly, in the second engaging portions (339, 341), a retaining portion (partition wall 344) is positioned between the inner peripheral side protrusions 339 (outer peripheral side recessed portions 341) that are adjacent in the axial direction. As a result, the first engaging portions (321, 338) and the second engaging portions (339, 341) can have both anti-rotation and anti-disengagement functions due to the engagement of the recesses and protrusions provided therein. .

Now, let us consider the shear stress that the engaging portions (the first engaging portion and the second engaging portion) that function as the key (mechanical element that fastens the rotating body to the shaft) receive when the rotor 3 rotates. Assuming that the engagement portion (key) is located at a radius r [m] from the central axis O on the shaft that transmits torque having a magnitude of T [N·m], the first engagement portion and the first Assuming that the shape of the two engaging portions is uniform, the shear stress τ [Pa] acting on each engaging portion can be expressed by τ=α×T/r (α: constant of proportionality). In addition, the radial position of the first engaging portion provided between the outer core 32 and the insulating member 33 (that is, the inner diameter of the outer core 32) r1 and the distance between the insulating member 33 and the inner core 34 When comparing the radial position of the second engaging portion (that is, the outer diameter of the inner peripheral iron core 34) r2, r1>r2 is always established.
Furthermore, the torque transmitted between the outer core 32 and the insulating member 33 and the torque transmitted between the insulating member 33 and the inner core 34 can be considered equal. Therefore, the shear stress τ1 acting between the members on the outer diameter side (the first engaging portion between the outer core 32 and the insulating member 33) is greater than the shear stress τ1 between the members on the inner diameter side (the inner core 34 and the insulating member 33). The shear stress τ2 acting on the second engaging portion between ) is always larger (that is, τ1<τ2 is always established). Therefore, the number of second engaging portions (the number of outer recessed portions 341 formed in the inner peripheral iron core 34) in the circumferential direction is made greater than the number of first engaging portions 321 and 338 in the circumferential direction. Thus, the shear stress acting on the individual first engaging portions 321 and 338 provided between the members on the inner diameter side can be reduced, and the anti-rotation of the insulating member 33 can be further strengthened.

As shown in FIGS. 4 to 9, the insulating member 33 has a first axial hole, which is a plurality of grooves for increasing the impedance (reducing the capacitance) of the rotor 3, at one end in the axial direction. 331 are formed, and second axial holes 332, which are a plurality of grooves for similarly increasing the impedance of the rotor 3 (reducing the capacitance), are formed at the other end in the axial direction. In addition, while the dielectric constant of insulating members (elastomers, etc.) is about 2 to 3, the dielectric constant of air is approximately 1, and the impedance of the air layer is higher than that of the insulating member itself. expensive. Therefore, by providing the insulating member 33 with grooves (the first axial hole 331 and the second axial hole 332), an air layer is formed in the insulating member 33, and the impedance of the rotor 3 can be further increased. .

A plurality (for example, eight) of these first axial holes 331 and second axial holes 332 (grooves) are formed at equal intervals in the circumferential direction. Between each of the plurality of first axial holes 331 and between each of the plurality of second axial holes 332, radial connecting portions (partition walls) 334 are uniformly formed and are circumferentially adjacent to each other. It separates the first axial holes 331 and the second axial holes 332 adjacent in the circumferential direction. Here, the plan view and bottom view of the rotor 3 are the same. The radial connecting portion 334 has a small (short) length in the radial direction, thereby suppressing a decrease in mechanical strength. can be transmitted without waste.

Furthermore, as shown in FIGS. 6 to 9, the first axial hole 331 and the second axial hole 332 are axially opposed to each other, and are axially centered (axially opposed) of the insulating member 33 . A wall portion 333 is provided between the first axial hole 331 and the second axial hole 332) so that the depths of the holes are the same. The wall portion 333 enhances the mechanical strength of the connecting member 33 and can improve the efficiency of power transmission from the outer core 32 to the inner core 34 .
Further, by providing this wall portion 333, the bottom portion 33c of the first axial hole 331 is formed on one end side of the wall portion 333, and the bottom portion of the second axial direction hole 332 is formed on the other end side of the wall portion 333. 33c is formed. In the insulating member 33 (connecting member), an inner annular portion 33i and an outer annular portion 33o are formed along the axial direction from the bottom portions 33c of the first axial hole 331 and the second axial hole 332, respectively. .

In this manner, the first axial hole 331 and the second axial hole 332 form a bottomed hole (groove) in the axial direction by forming the wall portion 333 . In addition, the first axial hole 331 and the second axial hole 332 are formed in an arcuate shape along the circumferential direction when viewed from the axial direction, and are partitioned by radial connecting portions 334, A plurality of them (for example, eight in the circumferential direction) are formed at regular intervals.

Here, for example, when the radial length (width) of the connecting member (insulating member 33) is small, the radial length (width) R of the first axial hole 331 and the second axial hole 332 is also small and limited. Therefore, there is a limit to increasing the impedance of the rotor 3 . Therefore, in the present embodiment, as shown in FIG. The above-described grooves (the first axial hole 331 and the second axial hole 332) are formed at positions on the outer diameter side of the outer peripheral surface 345. As shown in FIG.
As a result, for example, an air layer having a higher impedance than a connecting member made of an insulating member is formed between the inner peripheral surface 324 and the outer peripheral surface where the outer peripheral side iron core 32 and the inner peripheral side iron core 34 are closest in the radial direction. 345 can be provided. As a result, for example, the impedance between the outer core 32 and the inner core 34 of the rotor 3 having a connecting member (insulating member 33) with a small radial width can be further increased, and electrolytic corrosion of the bearing can be prevented. can be further suppressed.

The insulating member 33 (connecting member) has an outer annular portion 33o, an inner annular portion 33i, and a plurality of radial connecting portions 334 that connect the outer annular portion 33o and the inner annular portion 33i. In other words, the grooves (the first axial hole 331 and the second axial hole 332) are arranged between the adjacent radial connecting portions 334 in the circumferential direction. As a result, the length (width) in the circumferential direction of the radial coupling portion 334 formed of an insulating member having a higher dielectric constant (lower impedance) than air can be reduced, and the outer core 32 and the inner Impedance between the peripheral iron cores 34 can be increased. Further, as described above, by providing the radial connecting portion 334 having a small (short) radial length, a decrease in the mechanical strength of the connecting member 33 is suppressed, and the movement from the outer core 32 to the inner core 34 is suppressed. power can be sufficiently transmitted.

Also, the first axial hole 331 and the second axial hole 332 are formed so that their circumferential lengths are longer than their radial lengths. As a result, in the region between the outer core 32 and the inner core 34, the ratio of the air layer having the highest impedance can be increased, and the impedance of the rotor 3 can be increased.

Furthermore, at least one of the plurality of radial connecting portions 334 is formed at a position corresponding to the inner peripheral recess 321 and the outer peripheral recess 341 in the radial direction, as shown in FIG. 8 . As a result, at least one of the radial coupling portions 334 formed of an insulating material having a lower impedance than the air layer is arranged at a position where the distance between the outer peripheral side iron core 32 and the inner peripheral side iron core 34 is the longest. The impedance of child 3 can be increased. In addition, since a part of the insulating member 33 (the radial connecting portion 334 sandwiched between the outer peripheral convex portion 338 and the inner peripheral convex portion 339) is held from both sides in the radial direction, the detent becomes stronger.

As described above, the size, shape, and number of the first axial holes 331 and the second axial holes 332 are determined in consideration of both improving the impedance of the rotor 3 (reducing the capacitance) and ensuring mechanical strength. determined by

By the way, generally, the coefficient of linear expansion of elastomer (rubber) is larger than that of metal. Therefore, the insulating member 33 made of elastomer expands more when the temperature rises and contracts more when the temperature drops than the outer core 32 and the inner core 34 made of metal.

The insulating member 33 is radially thin and axially thick, as shown in FIG. Therefore, the amount of expansion and contraction of the insulating member 33 tends to be greater in the axial direction than in the radial direction. The amount of expansion and contraction of the wall portion 333 and the partition wall 334 of the insulating member 33 can be divided into a component in the radial direction and a component in the axial direction. Since it is regulated by the iron core 34, the amount of expansion and contraction in the axial direction tends to be greater than the amount of expansion and contraction in the radial direction.

Moreover, thermal stress is likely to concentrate at a portion of the insulating member 33 where expansion and contraction in the radial direction are restricted by the outer core 32 and the inner core 34 .

However, in the present embodiment, since the insulating member 33 is made of elastic elastomer, it is possible to suppress cracks due to stress. In addition, since the insulating member 33 is formed with the grooves (the first axial hole 331 and the second axial hole 332), the insulating member 33 can expand or contract radially toward the grooves. As a result, expansion and contraction of the insulating member 33 in the axial direction can be relatively suppressed. In addition, since the insulating member 33 is made of a soft elastomer, the vibration is easily damped, and the vibration of the electric motor 1 having the rotor 3 can be reduced.
Therefore, since the vibration generated in the insulating member 33 (electric motor 1) can be suppressed, the motor of the electric motor 1 provided when the electric motor 1 is fixed to the pedestal 104 (see FIG. 12) of the outdoor unit 10 (blower) The anti-vibration rubber interposed between the outer shell 6 and the pedestal 104 may be omitted. In this case, the number of parts for fixing the electric motor 1 can be reduced.

Further, as shown in FIG. 7 , the insulating member 33 has axial ends 33 d partially covering both axial end faces of the outer core 32 and the inner core 34 . As a result, it is possible to prevent the relative positions of the rotor cores (the outer core 32 and the inner core 34 ) from being displaced with respect to the insulating member 33 . Further, both axial end surfaces of the outer annular portion 33o, the inner annular portion 33i, and the radial connecting portion 334 of the insulating member 33 are flush with each other. As a result, the force applied to the radial connecting portion 334 can be dispersed, and the strength of the insulating member 33 can be increased.

As described above, the rotor 3 of the present embodiment maintains the strength of the connection between the outer core 32 and the inner core 34 while increasing the impedance therebetween (reducing the capacitance). It is possible to suppress the occurrence of electrolytic corrosion of the bearing.

At least one of the first axial hole 331 and the second axial hole 332 may be attached with a member (resin, metal, etc.) for adjusting capacitance and durability.

Further, in each of the above-described embodiments, the end face shape of the first axial hole 331 and the second axial hole 332 as seen from the axial direction is arc-shaped along the circumferential direction. The shape of the axial hole (groove) is not limited to this. Also, the number of first axial holes 331 and second axial holes 332 (or the number of radial connecting portions 334) is not limited to eight, and may be any number.

In each of the above-described embodiments, the first axial hole 331 and the second axial hole 332 are formed in a symmetrical shape with respect to the wall portion 333, but are not limited to this. The direction hole 331 and the second axial hole 332 may be formed in an asymmetrical shape (for example, C-shaped when viewed in the axial direction) with respect to the wall portion 333 .

Furthermore, in each of the above-described embodiments, the case where the present invention is applied to the surface magnet type rotor 3 in which the permanent magnets 31 are arranged on the outer peripheral surface of the outer core 32 has been described, but the present invention is not limited to this. The present invention can also be applied to an embedded magnet type rotor in which slots extending in the axial direction are formed at chord positions with respect to the outer peripheral surface of the outer core 32 and permanent magnets are arranged in these slots.

DESCRIPTION OF SYMBOLS 1... Permanent magnet motor 2... Stator 10... Outdoor unit 101... Base 102... Bottom plate 103... Top plate 104... Pedestal 105... Support 21... Stator core 22... Insulator 23... Winding 3... Rotor 31... Permanent magnet 311 ... Permanent magnet piece 32 ... Outer circumference iron core 321 ... Inner circumference recess (first engaging portion) (recess of engaging portion)
323... Partition (first retaining portion)
33... Insulating member (connecting member)
331... First axial hole (groove)
332... Second axial hole (groove)
333... Wall portion 334... Radial connection portion (partition wall)
33i... Inner annular portion (side wall)
33o... Outer annular portion (side wall)
33c... Bottom part 33d... End part 338... Outer peripheral side convex part (first engaging part) (convex part of engaging part)
339... Inner periphery side convex portion (second engaging portion) (convex portion of engaging portion)
34... Inner peripheral core 341... Outer peripheral recess (second engagement portion) (recess of engagement portion)
343... Through hole 344... Partition (second retaining portion)
35... Shaft 41... First bearing 42... Second bearing 51... First bracket 511... First bearing housing portion 512... Flange portion 52... Second bracket 520... Outer edge portion 522... Second bearing housing portion O... Center shaft

Claims (9)

An outer core, an inner core, and an insulating connecting member that connects the outer core and the inner core,
A plurality of annularly arranged grooves are formed in the connecting member,
The outer core is formed with a plurality of inner recesses that are recessed in the outer diameter direction from the inner peripheral surface of the outer core,
The inner peripheral core is formed with a plurality of outer peripheral recesses that are recessed in the radial direction from the outer peripheral surface of the inner peripheral core,
The connecting member has an outer annular portion, an inner annular portion, and a plurality of radial connecting portions that connect the outer annular portion and the inner annular portion;
The groove portion is arranged at a position on the inner diameter side with respect to the inner peripheral surface of the outer peripheral side iron core and at a position on the outer diameter side with respect to the outer peripheral surface of the inner peripheral side iron core , and is adjacent in the circumferential direction. arranged between the radial connecting portions,
At least one of the radial connecting portions is formed at a position corresponding to the inner peripheral side recess and the outer peripheral side recess in the radial direction.
rotor. An outer core, an inner core, and an insulating connecting member that connects the outer core and the inner core,
A plurality of annularly arranged grooves are formed in the connecting member,
The outer core is formed with a plurality of inner recesses that are recessed in the outer diameter direction from the inner peripheral surface of the outer core,
The inner peripheral core is formed with a plurality of outer peripheral recesses that are recessed in the radial direction from the outer peripheral surface of the inner peripheral core,
The groove portion is arranged at a position on the inner diameter side with respect to the inner peripheral surface of the outer peripheral side iron core and at a position on the outer diameter side with respect to the outer peripheral surface of the inner peripheral side iron core,
The location where the outer core and the inner core are closest in the radial direction is between the inner peripheral surface of the outer core and the outer peripheral surface of the inner core.
rotor. An outer core, an inner core, and an insulating connecting member that connects the outer core and the inner core,
A plurality of annularly arranged grooves are formed in the connecting member,
The outer core is formed with a plurality of inner recesses that are recessed in the outer diameter direction from the inner peripheral surface of the outer core,
The inner peripheral core is formed with a plurality of outer peripheral recesses that are recessed in the radial direction from the outer peripheral surface of the inner peripheral core,
The groove portion is arranged at a position on the inner diameter side with respect to the inner peripheral surface of the outer peripheral side iron core and at a position on the outer diameter side with respect to the outer peripheral surface of the inner peripheral side iron core ,
A first retaining portion for preventing the connecting member from slipping off in the axial direction with respect to the outer core is formed at a position overlapping the inner peripheral recess in the axial direction, and a position overlapping the outer peripheral recess in the axial direction. is formed with a second retaining portion that retains the connecting member from the inner peripheral iron core in the axial direction.
rotor. An outer core, an inner core, and an insulating connecting member that connects the outer core and the inner core,
A plurality of annularly arranged grooves are formed in the connecting member,
The outer core is formed with a plurality of inner recesses that are recessed in the outer diameter direction from the inner peripheral surface of the outer core,
The inner peripheral core is formed with a plurality of outer peripheral recesses that are recessed in the radial direction from the outer peripheral surface of the inner peripheral core,
The groove portion is arranged at a position on the inner diameter side with respect to the inner peripheral surface of the outer peripheral side iron core and at a position on the outer diameter side with respect to the outer peripheral surface of the inner peripheral side iron core ,
The number of the outer peripheral recesses in the circumferential direction is greater than the number of the inner peripheral recesses in the circumferential direction.
rotor. The rotor according to any one of claims 2 to 4 ,
The connecting member has an outer annular portion, an inner annular portion, and a plurality of radial connecting portions that connect the outer annular portion and the inner annular portion;
The groove portion is arranged between the radial connecting portions adjacent to each other in the circumferential direction of the rotor. A rotor according to claim 5,
At least one of the radial connecting portions is formed at a position corresponding to the inner peripheral side recess and the outer peripheral side recess in the radial direction. The rotor according to any one of claims 1, 5 or 6 ,
The connecting member covers part of both axial end faces of the outer core and the inner core,
The axial end surfaces of the outer annular portion, the inner annular portion, and the radial coupling portion are formed flush with each other. The rotor according to any one of claims 1 to 7,
The connecting member is made of polypropylene (PP) or ethylene propylene rubber (EPDM). Rotor. An electric motor, comprising: the rotor according to any one of claims 1 to 8; and a stator arranged on the outer diameter side of the rotor.

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