JP3835231B2 - Electric motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
It belongs to a synchronous rotating machine configured using permanent magnets.
[0002]
[Prior art]
A rotor including a magnet groove for embedding a plurality of permanent magnets, a permanent magnet embedded in the magnet groove, a stator having a plurality of slots, and a coil portion having windings in the slots; In order to generate high torque with less current in an electric motor that is driven to rotate by reluctance torque, a coil and a chain arranged on the stator side have a little more magnetic flux generated by a permanent magnet embedded in the rotor. It is necessary to make them interact. Thereby, it is possible to effectively use the magnet torque. In order to effectively use the reluctance torque, a permanent magnet is embedded in the rotor, the q-axis inductance on the q-axis side having a small magnetic resistance on the magnetic circuit viewed from the outside of the rotor, and a magnet groove in which the permanent magnet is embedded. In addition, it is necessary to increase the difference in d-axis inductance on the d-axis side, which has a very large magnetic resistance due to the flux barrier. At that time, in order to effectively link the magnetic flux of the permanent magnet to the coil on the stator side, it is necessary to make the bridge width, which is the distance between the end of the permanent magnet and the flux barrier, and the outer periphery of the rotor as narrow as possible. . By performing such a design, the bridge portion can be magnetically saturated with a smaller number of permanent magnet magnetic fluxes, and as a result, more permanent magnet magnetic fluxes can be linked to the coils on the stator side.
[0003]
However, when narrowing the bridge width, which is the distance between the permanent magnet end and flux barrier end and the outer periphery of the rotor, it is necessary to sufficiently consider the breaking strength against centrifugal force when the rotor rotates. That is, as the bridge width is narrowed, the leakage magnetic flux that is short-circuited inside the rotor can be reduced, and high torque can be obtained with less current, but the weight of the rotor core on the entire surface of the permanent magnet and permanent magnet is supported. Since the stress applied to the bridge portion is high, the risk of the rotor breaking during rotation is very high.
[0004]
[Problems to be solved by the invention]
The following solutions have been proposed as means for overcoming the danger.
[0005]
By dividing and arranging the magnet groove for embedding the permanent magnet within the same magnetic pole, the weight of the rotor core of the permanent magnet and the entire permanent magnet is used in the same magnetic pole other than the bridge portion of the rotor surface. This is a method of dispersing. However, in this case, since the magnetic flux of the permanent magnet is short-circuited via the bridge portion and the rib arranged in the same magnetic pole, it is difficult to increase the magnetic flux linked to the coil.
[0006]
The present invention proposes a rotor structure capable of generating a high torque using a smaller amount of current by narrowing the bridge width, which is the distance between the end of the permanent magnet and the outer periphery of the rotor. In addition, when the rotor rotates at a high speed at that time, the risk of the rotor breaking during rotation is small.
[0007]
[Means for Solving the Problems]
An electric motor structure according to the present invention includes a rotor having a magnet groove in which a plurality of permanent magnets are embedded, a permanent magnet embedded in the magnet groove, a stator having a plurality of slots, and a coil in which windings are provided in the slots. An electric motor that is rotationally driven by magnet torque and reluctance torque, wherein there are two or more magnet grooves provided in the same magnetic pole of the rotor in the circumferential direction, and the magnet groove and the magnet groove in the same magnetic pole dividing the permanent magnet into two or more segments through a division portion between the flux barriers are arranged behind the divided portion, two or more arranged on the front surface of the flux barrier in the center of the flux barrier in the electric motor of the permanent magnet is arranged a permanent magnet of the same pole is divided into segments, which is disposed in front of the flux barrier in the center of the flux barrier 2 Characterized in that a permanent magnet is the same magnetic pole and divided permanent magnet or more segments.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes a rotor having a magnet groove for embedding a plurality of permanent magnets, a permanent magnet embedded in the magnet groove, a stator having a plurality of slots, and a coil portion in which the slots are wound. , An electric motor driven to rotate by magnet torque and reluctance torque, wherein there are two or more magnet grooves provided in the same magnetic pole of the rotor in the circumferential direction, and the division between the magnet groove and the magnet groove in the same magnetic pole An electric motor having a structure in which a permanent magnet is divided into two or more segments through a section and a flux barrier is disposed behind the divided section.
[0009]
In the present invention, as shown in FIG. 1, the permanent magnet disposed inside the rotor has a structure in which it is divided into two or more segments, and a flux barrier serving as a magnetic flux barrier is disposed behind the permanent magnet. And Even if the bridge width, which is the distance between the end of the permanent magnet and the outer periphery of the rotor, is reduced by this structure, the weight of the permanent magnet and the front of the permanent magnet is supported by the rib structure between the permanent magnet poles in addition to the flux barrier. Therefore, sufficient breaking strength can be maintained even when the rotor rotates at high speed.
[0010]
In addition, the magnetic flux of the permanent magnet that is short-circuited at the rib structure between the permanent magnet poles at that time can be magnetically saturated by the flux barrier disposed at the back, so that the magnetic flux that is short-circuited at the rib structure can be reduced. It is. For this reason, it is possible to minimize the magnetic flux that is short-circuited inside the rotor via the bridge part and the rib structure part, it is possible to obtain high torque with less current, Even if it rotates at a high speed, it is possible to guarantee a sufficient strength for the breaking strength.
[0011]
Further, as shown in FIG. 2, the permanent magnet disposed in the rotor is divided into two or more segments, a flux barrier serving as a magnetic flux barrier is disposed behind the permanent magnet, and the center of the flux barrier is further disposed. The same effect can be obtained by using a structure in which a permanent magnet having the same magnetic pole as that of the permanent magnet is disposed in the part. Even if the bridge width, which is the distance between the end of the permanent magnet and the outer periphery of the rotor, is reduced by this structure, the weight of the permanent magnet and the front of the permanent magnet is supported by the rib structure between the permanent magnet poles in addition to the flux barrier. Therefore, sufficient breaking strength can be maintained even when the rotor rotates at high speed.
[0012]
Moreover, it is possible to prevent the short circuit of the magnetic flux by the rib structure part by repelling the magnetic flux of the permanent magnet which is short-circuited at the rib structure part between the permanent magnet poles by the permanent magnet disposed behind. For this reason, it is possible to minimize the magnetic flux that is short-circuited inside the rotor via the bridge part and the rib structure part, it is possible to obtain high torque with less current, Even if it rotates at a high speed, it is possible to guarantee a sufficient strength for the breaking strength.
[0013]
【Example】
( Reference Example)
FIG. 1 shows a reference embodiment. FIG. 1 shows a rotor 5 having 8 magnetic poles having a plurality of permanent magnet embedded grooves 11 to 12 and 21 to 22, permanent magnets 14 to 15 and 24 to 25 embedded in the magnet grooves, and 12 slots. An electric motor that includes a stator 1 and a coil portion in which windings 2 to 4 of U, V, and W are sequentially arranged in the slots, and is driven to rotate by magnet torque and reluctance torque, and is disposed inside the rotor. A configuration of an electric motor in which the permanent magnets 14 to 15 and 24 to 25 are divided into two segments at the center of each magnetic pole, and a flux barrier 31 as a magnetic flux barrier is provided behind the permanent magnets 14 to 15 and 24 to 25 is shown.
[0014]
With this configuration, the weight of the iron portion in front of the permanent magnets 14 to 15 and 24 to 25 is set to the left side of the permanent magnets 14 and 24, the bridge portion on the right side of the permanent magnets 15 and 25, and the intermediate part of the permanent magnets 14 and 15, Since it can be supported by the magnetic pole intermediate portions of the permanent magnets 24 and 25, the bridge width can be made narrower than that of a rotor in which a conventional permanent magnet is not divided into a plurality of segments. At that time, in addition to the leakage magnetic flux that is short-circuited inside the rotor through the bridge portion, a leakage magnetic flux that is short-circuited inside the rotor through the magnetic pole intermediate portions of the permanent magnets 14, 15 and 24, 25 is generated. By providing the flux barrier 31 behind the permanent magnet, the latter leakage magnetic flux can magnetically saturate the magnetic pole intermediate portions of the permanent magnets 14, 15 and 24, 25 with less magnetic flux, resulting in the same magnet The amount can be used to increase the amount of magnetic flux interlinked with the windings rather than a rotor in which a conventional permanent magnet is not divided into a plurality of segments.
[0015]
Incidentally, the flux barrier 31 shown in this reference example along the pole intermediate part of the permanent magnets 14, 15, and 24, 25 in order to effectively magnetically saturate the leakage flux short-circuited internally rotor intermediate If the shape is intended to magnetically saturate the magnetic pole middle part, for example, the end plate or balance weight as shown in FIG. 3 can be fixed to the rotor. For the purpose, the same effect can be obtained by also using the through hole 32 formed in the rotor.
[0016]
(Example 1 )
FIG. 2 shows an embodiment of the present invention. FIG. 2 shows a rotor 5 having 8 magnetic poles having a plurality of permanent magnet embedded grooves 11 to 13 and 21 to 23, permanent magnets 14 to 16 and 24 to 26 embedded in the magnet grooves, and fixing of 12 slots. An electric motor that includes a child 1 and a coil portion in which windings 2 to 4 of U, V, and W are sequentially arranged in the slots, and is driven to rotate by magnet torque and reluctance torque, and is disposed inside the rotor. The permanent magnets 14 to 15 and 24 to 25 have a structure in which the magnetic poles are divided into two segments at the center of each magnetic pole, and a flux barrier 31 that is a magnetic flux barrier is provided behind the permanent magnets. The structure of an electric motor provided with the structure which has arrange | positioned the permanent magnets 16 and 26 of the same magnetic pole as the magnets 14-15 and 24-25 is shown.
[0017]
With this configuration, the weights of the iron portions of the front portions of the permanent magnets 14 to 15 and 24 to 25 are set to the left side of the permanent magnets 14 and 24, the bridge portion on the right side of the permanent magnets 15 and 25, and the permanent magnets 14, 15 and 24, Since it can be supported by 25 magnetic pole intermediate portions, the bridge width can be made narrower than that of a rotor in which a conventional permanent magnet is not divided into a plurality of segments.
[0018]
At that time, in addition to the leakage magnetic flux that is short-circuited inside the rotor through the bridge portion, a leakage magnetic flux that is short-circuited inside the rotor through the magnetic pole intermediate portions of the permanent magnets 14, 15 and 24, 25 is generated. The latter leakage magnetic flux can be suppressed to a minimum by repelling the magnetic flux generated by the permanent magnets 16 and 26 disposed behind the permanent magnet. As a result, the conventional permanent magnet is used with the same magnet amount. It is possible to increase the amount of magnetic flux linked to the winding rather than the rotor in which the magnet is not divided into a plurality of segments.
[0019]
The stator winding method shown in the present embodiment is so-called concentrated winding in which windings 2 to 4 of U, V, and W are sequentially arranged in the slots, respectively. The same effect can be obtained with so-called distributed windings that are arranged across the windings 2 to 4 of W.
[0020]
【The invention's effect】
According to the first aspect of the present invention , a flux barrier is disposed behind a permanent magnet that is divided and embedded inside the rotor, and a permanent magnet having the same magnetic pole as that of the permanent magnet is disposed at the center thereof. Magnetic flux interlinked with the stator winding with the same breaking strength as a rotor composed of permanent magnets embedded without dividing, reducing leakage magnetic flux that short-circuits inside the rotor while maintaining the breaking strength of Can be increased.
[0021]
Further, the flux barrier according to claim 1 can be used as a through-hole formed in the rotor for the purpose of fixing the rotor to the end plate, balance weight, etc., which is absolutely necessary for the configuration of the rotor. By effectively using the through hole, a simple rotor shape can be obtained, and the cost can be reduced.
[0022]
Further, if the invention of claim 1 is constituted by a permanent arc and a flux barrier having a reverse arc shape when viewed from the rotation axis of the rotor, the permanent magnet and flux barrier perpendicular to the magnetic pole of the rotor of claim 1 It is possible to increase the reluctance torque by making the difference in dq axis inductance larger than in the case of the above configuration.
[0023]
Further, if the invention of the first aspect is configured by using two or more layers of permanent magnets and a flux barrier, the difference in dq axis inductance is made larger than that of the two-layer structure of the first aspect. It is possible to increase the reluctance torque.
[Brief description of the drawings]
Other references embodiment disclosed exemplary cross-sectional view of a synchronous motor showing the configuration of Embodiment 1 of Reference Example sectional view of a synchronous motor showing the arrangement of Figure 2 The present invention the present invention; FIG Sectional view of synchronous motor showing configuration
DESCRIPTION OF SYMBOLS 1 Stator 2 U phase winding 3 V phase winding 4 W phase winding 5 Rotor 6 Rotating shaft 11, 12 Permanent magnet embedded groove 14, 15 Permanent magnet 31 Flux barrier 32 Through hole

Claims (1)

A rotor including a magnet groove for embedding a plurality of permanent magnets, a permanent magnet embedded in the magnet groove, a stator having a plurality of slots, and a coil portion having windings in the slots; And an electric motor that is rotationally driven by a reluctance torque, and there are two or more magnet grooves provided in the same magnetic pole of the rotor in the circumferential direction, and a part between the magnet groove and the magnet groove in the same magnetic pole is interposed. The permanent magnet is divided into two or more segments, a flux barrier is disposed behind the divided portion, and the permanent magnet is divided into two or more segments disposed in front of the flux barrier at the center of the flux barrier. An electric motor comprising a permanent magnet having the same magnetic pole as a magnet.

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