CN203027042U - Permanent magnet type synchronous motor - Google Patents

Abstract

The utility model discloses a permanent magnet type synchronous motor capable of sufficiently inhibiting cogging torques of the 2f component and the 4f component. The permanent magnet type synchronous motor comprises: Z stator slots (21) which are formed into in a circular ring shape and applied with a winding; a rotor (1) which is configured in the circular ring formed by the stator slots (21); and a 2P pole annular magnet (11) which is formed with the rotor (1) into an integral body and configured in a manner that the 2P pole annular magnet (11) is opposite to the stator slots (21). The permanent magnet type synchronous motor is configured in a manner that the value of Z/{3(phase)*2P} is 2/5 or 2/7. One surface of the annular magnet (11) which is opposite to the stator slots (21) is provided with continuous skew whose electrical degree is in the range from 42 degrees to 128 degrees relative to the axial direction of the rotor (1).

Description

Permanent magnet synchronous motor

technical field

The utility model relates to a permanent magnet synchronous motor driven by a 3-phase power supply, in particular to a new and improved technology for effectively suppressing cogging torque. the

Background technique

Generally, in a permanent magnet synchronous motor, when the rotor magnet (rotor) is rotated by an external drive while the winding is not energized, a cogging torque is generated between the stator core and the rotor. the

This cogging torque is caused by the pulsation of the least common multiple of the number of stator slots and the number of permanent magnet poles every time the rotor rotates mechanically, and the magnitude of the cogging torque is inversely proportional to the number of pulsations. the

In a permanent magnet synchronous motor driven by 3-phase AC, the cogging torque generated when no power is applied can be reduced by appropriately selecting the combination of the number of magnetic poles and the number of slots. the

In general, in order to suppress the cogging torque of the permanent magnet synchronous motor, it is necessary to select a large combination of the least common multiple of the number of stator slots and the number of permanent magnet poles. the

As an example of a large combination of the least common multiple, in a so-called permanent magnet synchronous motor driven by a 3-phase power supply, the following structure can be cited: Z pieces ( Z is a natural number) In the case of a stator slot and a permanent magnet having 2P poles (P is a natural number), the value of Z/{3 (phase)×2P} is "2/5" or "2/7". the

For example, in a permanent magnet synchronous motor whose value of Z/{3(phase)×2P} is "2/5", when the number of magnetic poles is "10", the number of slots is "12", and the number of passing poles The cogging torque generated by the combination of the number of slots and the number of slots produces only "60 peaks" during one revolution of the rotor. the

In addition, in general, permanent magnet synchronous motors also have cogging torque due to manufacturing errors, magnetic anisotropy of electromagnetic steel sheets, etc. degree) is called "1f", the cogging torque of the 2f component (with an electrical angle of 180 degrees as a cycle) and the 4f component (with an electrical angle of 90 degrees as a cycle) will be generated due to the manufacturing error of the stator, etc. . the

In particular, when the stator core is manufactured by shrink-fitting the stator core in the diameter of a frame whose inner diameter is circular and the outer side is a quadrangular shape, or by stacking the rolling direction of the electromagnetic steel sheets in the same direction, the cogging torque The 4f component is greatly generated. the

On the other hand, conventionally, there has been proposed a technique for suppressing the generation of cogging torque by providing skew (Skew: forming the core or magnetization obliquely with respect to the axial direction) (for example, refer to Patent Document 1). the

Prior Art Literature

Patent Documents

Patent Document 1: Japanese Utility Model Publication No. 2558514

Utility model content

Problems to be solved by the utility model

In the previous permanent magnet synchronous motor, in order to reduce the cogging torque caused by the pulsation, a large combination of the number of stator slots and the least common multiple of the number of permanent magnet poles was selected, but there were the following problems: The cogging torque generated in the case of 10 poles and 12 slots has 60 peaks during one revolution of the rotor, and due to manufacturing errors, magnetic anisotropy of the electromagnetic steel plate, etc., the cogging torque of the 4f component moment will be greatly generated. the

Also, even when a skew is provided as in Patent Document 1, there is a problem that the cogging torque cannot be sufficiently suppressed because the electrical angle of the skew is small (about 20 degrees to 40 degrees). the

The utility model is made in order to solve the above problems, and the purpose is to obtain a permanent magnet synchronous motor capable of sufficiently suppressing the cogging torque of the 2f component and the 4f component. the

means for solving problems

The permanent magnet synchronous motor of the utility model has: Z (Z is a natural number) stator slots formed into a ring shape and applied with windings; a rotor arranged in the ring shape of the stator slot; 2P poles (P is a natural number) permanent magnets arranged opposite to the stator slots. The permanent magnet synchronous motor is composed of Z/{3 (phase) × 2P} with a value of 2/5 or 2/7. Among them, in The surface of the permanent magnet facing the stator slot is provided with a continuous skew with an electrical angle of 42 degrees to 128 degrees relative to the axial direction of the rotor. the

In the permanent magnet synchronous motor described above, preferably, the continuous skew is provided such that a start position and an end position of the skew angle in the axial direction of the rotor are the same with respect to the rotation direction of the rotor. the

The permanent magnet synchronous motor of the present utility model has: Z stator slots, the stator slots are formed in an annular shape and applied with windings, Z is a natural number; the rotor is arranged in the annular shape of the Z stator slots ; and 2P pole permanent magnets, which are integrally formed with the rotor and arranged opposite to the stator slot, P is a natural number, and the permanent magnet synchronous motor has a value of Z/{3 (phase)×2P} 2/5 or 2/7, wherein, on the surface of the permanent magnet facing the stator slot, the electrical angle relative to the axial direction of the rotor is 42 degrees to 128 degrees, There is at least 2 more layer skews. the

In the above permanent magnet synchronous motor, preferably, the layer skew is composed of 2n+1 layers, and is set such that the start position and the end position of the skew angle are the same with respect to the rotation direction of the rotor, and n is a natural number. the

The permanent magnet synchronous motor of the present utility model has: Z stator slots, the stator slots are formed in an annular shape and applied with windings, Z is a natural number; the rotor is arranged in the annular shape of the Z stator slots ; and 2P pole permanent magnets, which are integrally formed with the rotor and arranged opposite to the stator slot, P is a natural number, and the permanent magnet synchronous motor has a value of Z/{3 (phase)×2P} 2/5 or 2/7, wherein, for the shape of the top end of the stator slot facing the permanent magnet, there is an electrical angle of 42 degrees to 128 degrees relative to the axial direction of the rotor. Continuous skew or layer skew. the

In the permanent magnet synchronous motor described above, it is preferable that the continuous skew or the layer skew is set such that a start position and an end position of the skew angle are the same with respect to a rotation direction of the rotor. the

utility model effect

According to the present invention, the 4f component of the cogging torque caused by the stator deviation can be reliably suppressed by providing the permanent magnet (rotor) with a continuous skew of 42 to 128 degrees in electrical angle. the

Description of drawings

1 is a sectional view showing a section perpendicular to an axial direction of a permanent magnet synchronous motor according to Embodiment 1 of the present invention. (Example 1)

2 is a cross-sectional view showing a cross-section perpendicular to the axial direction of a frame of the stator shown in FIG. 1 shrink-fitted. (Example 1)

3 is an explanatory view showing cogging torque generated by shrink fit of the stator into the frame, magnetic asymmetry in the rolling direction, and the like when no skew is provided. (Example 1)

FIG. 4 is an explanatory diagram showing the result of frequency analysis of the cogging torque in FIG. 3 . (Example 1)

Fig. 5 is an explanatory diagram showing a rolling direction of a general electrical steel sheet together with a cross-sectional view of a stator. (Example 1)

6 is a perspective view showing a state where no skew is provided to the ring magnet (rotor) in FIG. 1 . (Example 1)

Fig. 7 is a perspective view showing a ring magnet and a rotor provided with a continuous twist according to Embodiment 1 of the present invention. (Example 1)

8 is an explanatory diagram showing the relationship between the skew angle and the cogging torque (4f component) of the permanent magnet synchronous motor employing the rotor of FIG. 7 . (Example 1)

FIG. 9 is an explanatory diagram showing a relationship between a skew angle and a motor output of a permanent magnet synchronous motor employing the rotor of FIG. 7 . (Example 1)

Fig. 10 is a perspective view showing a ring magnet and a rotor provided with continuous skew according to Embodiment 2 of the present invention. (Example 2)

Fig. 11 is a developed view for explaining a method of manufacturing the ring magnet of Fig. 10 . (Example 2)

Fig. 12 is a developed view showing a combined state of two ring magnets in Fig. 11 . (Example 2)

Fig. 13 is a developed view of a case where the two-layer ring magnet of Fig. 11 is constituted by one ring magnet. (Example 2)

Fig. 14 is a perspective view showing a ring magnet and a rotor provided with layer skew according to Embodiment 3 of the present invention. (Example 3)

Fig. 15 is a developed view for explaining a method of manufacturing the ring magnet of Fig. 14 . (Example 3)

FIG. 16 is an explanatory diagram showing the relationship between the skew angle and the motor output of the permanent magnet synchronous motor employing the rotor of FIG. 14 . (Example 3)

17 is a sectional view showing a section perpendicular to the axial direction of a permanent magnet synchronous motor using sector magnets according to Embodiment 3 of the present invention. (Example 3)

FIG. 18 is a perspective view showing a state where no skew is provided to the ring magnet (rotor) in FIG. 17 . (Example 3)

Fig. 19 is a perspective view showing sector magnets and rotors provided with layer skew according to Embodiment 3 of the present invention. (Example 3)

Fig. 20 is a perspective view showing a ring magnet and a rotor provided with layer skew according to Embodiment 4 of the present invention. (Example 4)

Fig. 21 is a perspective view of a rotor in the case of employing sector magnets according to Embodiment 4 of the present invention. (Example 4)

22 is a cross-sectional view showing a cross-sectional shape of an axial upper end portion of one tooth of a stator slot according to Embodiment 5 of the present invention. (Example 5)

23 is a cross-sectional view showing a cross-sectional shape of an axial lower end portion of one tooth of a stator slot according to Embodiment 5 of the present invention. (Example 5)

24 is a perspective view showing the appearance of one tooth provided with continuously skewed stator slots according to Embodiment 5 of the present invention. (Example 5)

Fig. 25 is a perspective view showing a part of the inner surface structure of a stator formed by arranging a plurality of teeth of Fig. 24 . (Example 5)

Fig. 26 is a developed view planarly showing the tooth end face shape of the stator slot of Fig. 25 . (Example 5)

FIG. 27 is a perspective view showing another configuration example in which continuously skewed stator slots are provided according to Embodiment 5 of the present invention. (Example 5)

Fig. 28 is a developed view planarly showing the tooth end face shape of the stator slot of Fig. 27 . (Example 5)

29 is a perspective view showing the appearance of one tooth of a stator slot provided with layer skew according to Embodiment 5 of the present invention. (Example 5)

30 is a perspective view showing a part of the inner surface structure of a stator formed by arranging a plurality of teeth of FIG. 29 . (Example 5)

Fig. 31 is a developed view planarly showing the tooth end face shape of the stator slot of Fig. 30 . (Example 5)

32 is a perspective view showing another structural example of stator slots provided with layer skew according to Embodiment 5 of the present invention. (Example 5)

Fig. 33 is a developed view planarly showing the tooth end face shape of the stator slot of Fig. 32 . (Example 5)

Detailed ways

(Example 1)

Fig. 1 is a sectional view showing the basic structure of a permanent magnet synchronous motor according to Embodiment 1 of the present invention, showing a section perpendicular to the rotor axis direction. the

In FIG. 1 , a multi-pole (here, ten poles) ring magnet (permanent magnet) 11 is integrally formed on the outer peripheral portion of a rotor 1 constituted by a rotating shaft. the

Since the ring magnet 11 has a plurality of magnetic poles in a single permanent magnet, the boundaries between the magnetic poles cannot be seen visually, but in FIG. 1 , the boundary lines between the magnetic poles are shown for easy understanding. the

A stator 2 having multi-pole (here, 12 poles) stator slots 21 facing the ring magnet 11 is disposed on the outer peripheral portion of the rotor 1 . In addition, although not shown here, a coil is wound around each stator slot 21 . the

In addition, in FIG. 1 , taking the case where the number of magnetic poles 2P of the ring magnet 11 is 10 poles (P=5) and the number of slots Z is 12, the value of Z/{3 (phase)×2P} is set as The combination of 2/5 is not limited to this combination, and the value of Z/{3 (phase)×2P} can be set to 2/7 by combining 14 poles (P=7) rotor 1 and 12 slots. the

First, the cause of the cogging torque in the permanent magnet synchronous motor of FIG. 1 in the case where no skew is provided will be described with reference to FIGS. 2 to 6 . the

Fig. 2 is a cross-sectional view showing a frame 3 for fixing the stator 2 in Fig. 1 by shrink fit or the like, showing a cross section of the frame perpendicular to the axial direction. the

In FIG. 2 , the shape of the frame 3 is such that the inner diameter portion 31 of the shrink-fit stator 2 is processed into a circular shape, and the outer side is processed into a quadrangular shape. the

As shown in FIG. 2 , when using a frame 3 with different inner and outer shapes, when the stator 2 is shrink-fitted to the inner diameter portion 31, the stress applied to the stator 2 is different, so the core portion of the stator 2 is different. The BH curve changes according to the shrink fit stress. the

That is, when the stator 2 in FIG. 1 is shrink-fitted to the frame 3 in FIG. 2 , the stress received by the iron core of the stator 2 is different between the thicker part and the thinner part of the frame 3 . The shrink-fit stress of the given stator 2 also produces a difference. the

Therefore, in the stator 2 after shrink fitting, especially in the back part of the iron core of the stator 2, the BH curve will be different, and therefore, corresponding to the combination of the number of magnetic poles of the ring magnet 11 and the number of slots of the stator slot 21, in the rotor During one revolution, 10 and 20 torque ripples are generated. the

In particular, when shrink-fitting to a rectangular frame 3 as shown in FIG. 2 , magnetic imbalance occurs, and thus 20 pulsation components are strongly generated. the

Here, the number of magnetic poles of the ring magnet 11 (rotor 1) is 10. Therefore, if the frequency of the energized current for driving the motor is 1f, the pulsation components of 10 are "2f components" in terms of electrical angles, and 20 The pulsation component is "4f component". the

Fig. 3 is an explanatory diagram showing the cogging torque of a permanent magnet synchronous motor with the number of magnetic poles "10 poles" and the number of slots "12 slots", showing the ratio of one rotation of the rotor when no skew is provided. The cogging torque waveform actually generated during the period (0°~360°). the

In FIG. 3 , the amplitude of the cogging torque fluctuates several times due to magnetic asymmetry such as shrink-fitting the stator 2 into the rectangular frame 3 and the rolling direction of the stator 2 (described later together with FIG. 5 ). . the

4 is an explanatory diagram showing the result of frequency analysis of the cogging torque waveform in FIG. 3 , the horizontal axis represents the number of cogging torques per rotor revolution, and the vertical axis represents the magnitude of the cogging torque. the

Here, the permanent magnet synchronous motor is a combination of the number of magnetic poles "10 poles" and the number of slots "12 slots". Therefore, in FIG. During this period, "12" and "24" pulses are generated. the

In addition, "60" pulsations which are the least common multiple of the number of magnetic poles "10" and the number of slots "12" are generated. the

However, as shown in Fig. 4, "20" pulsation components (electrical 4f components) are greatly generated due to magnetic imbalance due to shrink fit stress. the

In addition, as mentioned above, the magnetic imbalance of the permanent magnet synchronous motor will also occur due to the rolling direction of the electromagnetic steel sheet. the

In general, in order to reduce the eddy current loss generated in the stator 2, an electric motor is produced by stacking electrical steel sheets. As the electrical steel sheets, there are oriented electrical steel sheets and non-oriented electrical steel sheets. the

In the case of any of these electrical steel sheets, at the stage of the strip forming the core group, although the amount of generation is different, there will be "differentiation based on the crystal shape" which is considered to be caused by the rolling direction and the non-rolling direction. Magnetic directionality", iron loss and magnetic flux density are different in the rolling direction and the non-rolling direction. the

That is, as shown in FIG. 5 , when the stators 2 are stacked and assembled with the rolling direction (see arrow) always in the same direction, cogging torque occurs due to the difference in the magnetic directionality of the stators 2 . the

As shown in FIGS. 3 and 4 , the cogging torque generated by such a difference in magnetic direction generates 20 large pulsation components. the

FIG. 6 is a perspective view of a general ring magnet 11 viewed from the axial direction, showing a state where the skew angle θ is 0 degrees (no twist). the

Next, the permanent magnet synchronous motor according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 7 to 9 . the

FIG. 7 is a perspective view showing the twisted annular magnet 11 and the rotor 1 according to Embodiment 1 of the present invention. the

The skew structure shown in FIG. 7 can be realized by setting the skew angle θ to the shape of the yoke (not shown) in advance when magnetizing the ring magnet 11 . the

As shown in FIG. 7 , by providing a skew to the ring magnet 11 (rotor 1 ), 20 ripple components of the cogging torque shown in FIGS. 3 and 4 can be reduced. the

FIG. 8 is an explanatory diagram showing cogging torque characteristics in the case of using the rotor 1 of FIG. 7 , showing the magnitude of the skew angle θ (horizontal axis) and the cogging torque of 20 pulsation components (vertical axis) The relationship between. the

The skew angle θ shown in FIG. 7 is shown in mechanical degrees, but the skew angle shown in FIG. 8 is shown in electrical degrees. the

As can be seen from FIG. 8 , 20 pulsation components (4f components) can be suppressed by setting the skew angle θ in a large range (for example, 42 degrees or more). the

On the other hand, in the case of the aforementioned Patent Document 1, the skew angle θ is set in a small area (electrical angle of 20 degrees to 40 degrees), and therefore, the 4f component cannot be sufficiently suppressed. the

In addition, FIG. 9 is an explanatory diagram showing the relationship between the skew angle θ (horizontal axis) and the output of the permanent magnet synchronous motor (vertical axis). the

It can be seen from FIG. 9 that the larger the value of the skew angle θ from 0 degrees, the lower the output of the motor. Therefore, setting the skew angle θ too large will lead to a decrease in the output of the motor. the

Therefore, in view of Fig. 8 and Fig. 9, the skew angle θ is preferably set to an electrical angle at which the 4f component is reduced by 2/3 or more (the effect is obvious) is 42 degrees or more, and the electrical angle at which the suppression effect is sufficiently obtained without greatly reducing the motor output Below 128 degrees. the

Accordingly, the 4f component of the cogging torque can be sufficiently reduced without greatly reducing the output of the motor. the

As mentioned above, the permanent magnet synchronous motor according to Embodiment 1 of the present utility model (Fig. 1 and Fig. 7) has: Z (Z is a natural number) stator slots 21 formed in an annular shape and applied with windings; The rotor 1 in the annular shape of 21; and the 2P pole (P is a natural number) ring magnet (permanent magnet) 11 which is integrally formed with the rotor 1 and arranged opposite to the stator slot 21, and constituted as Z/{3 (phase) ×2P} has a value of 2/5 or 2/7. the

On the surface of the ring magnet 11 facing the stator slot 21 , a continuous skew is provided at an electrical angle of 42° to 128° with respect to the axial direction of the rotor 1 . the

Accordingly, the 4f component and the 2f component of the cogging torque can be suppressed, and in particular, the 4f component of the cogging torque caused by the deviation of the stator 2 can be reliably suppressed. the

(Example 2)

In Embodiment 1 (FIG. 7) described above, continuous skew in one direction is provided. However, as shown in FIG. The start position and end position of the bevel angle θ are set in the same way to set the continuous skew. the

Fig. 10 is a perspective view showing the rotor 1 and the ring magnet 11 of the permanent magnet synchronous motor according to Embodiment 2 of the present invention, and the same reference numerals as above are assigned to the same parts as above, and detailed descriptions are omitted. In addition, the whole structure of Embodiment 2 of this invention is as shown in FIG. 1. the

In the case of providing continuous skew in one direction as in the aforementioned Embodiment 1 (Fig. 7), in the state where the permanent magnet synchronous motor is energized and a load is applied, it will be in the axial direction (thrust direction) of the rotor 1 If force is generated, the bearing (not shown) in the bearing unit may be damaged. Such bearing damage may cause abnormal noise and increase mechanical loss. the

On the other hand, by magnetizing the rotor so that the start position and the end position of the skew angle θ with respect to the rotation direction of the rotor 1 are the same as in Embodiment 2 of the present invention ( FIG. 10 ), it is possible to cancel out the thrust direction. force. the

That is, as shown in FIG. 10 , magnetization is performed such that the positions between the magnetic poles at the ends in the axial direction of the ring magnet 11 are the same, and the position between the magnetic poles at the central part in the axial direction is deviated by only the skew angle θ. Eliminate thrust in the axial direction. the

When manufacturing the ring magnet 11 (rotor 1) of FIG. 10, first, as shown in the developed view of FIG. Thus, magnetization is performed at the skew angle θ (42 degrees to 128 degrees) shown in FIG. 8 . the

Next, as shown in the developed view of FIG. 12 , the ring magnet 11 of FIG. 10 can be produced by combining and integrating the two magnetized ring magnets 11 in the axial direction. the

In addition, as shown in the developed view of FIG. 13 , a single ring magnet 11 having the same length as the axial length of the rotor 1 is prepared, and a magnetization yoke (not shown) is used in which the positions between the magnetic poles at the ends in the axial direction are set to be the same. (shown) to perform magnetization, so that the ring magnet 11 of FIG. 10 can also be produced. the

In Fig. 10, a ring magnet 11 (rotor 1) with 10 poles (P=5) is shown, but it is not limited to this, and it can also be applied to a permanent magnet synchronous motor set as follows: the number of poles is Combination of 14-pole rotor 1 and 12-slot, the value of Z/{3(phase)×2P} is 2/7. the

As mentioned above, according to Embodiment 2 of the present invention (Fig. 1, Fig. 10), continuous skew is set in such a manner that the start position and end position of the skew angle θ in the axial direction of the rotor 1 are the same. The 4f component of the cogging torque can eliminate the thrust generated by the skew and avoid bearing damage. the

(Example 3)

In addition, in the above-mentioned Embodiments 1 and 2 ( FIGS. 7 and 10 ), continuous skew was provided, but layered skew may be provided as shown in FIG. 14 . the

Fig. 14 is a perspective view showing the rotor 1 and the ring magnet 11 of the permanent magnet synchronous motor according to Embodiment 3 of the present invention, and the same reference numerals as above are assigned to the same parts as above, and detailed descriptions are omitted. In addition, the overall structure of Embodiment 3 of the present invention is as shown in FIG. 1 . the

In FIG. 14 , the ring magnet 11 is divided into two layers in the axial direction of the rotor 1 , and the positions of the respective magnetic poles are shifted by the skew angle θ with respect to the rotation direction of the rotor 1 . the

FIG. 15 is a developed view for explaining a method of manufacturing the ring magnet 11 (rotor 1 ) in FIG. 14 . the

As shown in Fig. 14 and Fig. 15, two layers of ring magnets 11 with no twist are used along the axial direction, and the position between the magnetic poles at the ends in the axial direction is shifted only by the skew angle θ ( 42 degrees to 128 degrees), thereby, the same effect as that of the first embodiment described above can be obtained. the

FIG. 16 is an explanatory diagram showing the relationship between the skew angle θ and the motor output of the permanent magnet synchronous motor using the ring magnet 11 (rotor 1 ) of FIG. 14 . the

In FIG. 16 , the motor output characteristic with respect to the skew angle θ is improved compared to the case of the aforementioned first embodiment ( FIG. 9 ). the

That is, in the case of FIG. 9, the skew angle θ that satisfies the motor output ≥ 0.8 is 0 degrees to about 130 degrees, but in the case of FIG. 16, the skew angle θ that satisfies the motor output ≥ 0.8 is 0 degrees to about 130 degrees. 150 degrees. the

Therefore, by providing layer skew as in Embodiment 3 of the present invention ( FIG. 14 ), it is possible to reduce the 4f component of the cogging torque without reducing the output of the motor. the

In Fig. 14, an integral ring magnet 11 is used, but as shown in Figs. 17 and 19, sector magnets 12 divided by magnetic poles may also be used. the

Fig. 17 is a sectional view showing another structural example of Embodiment 3 of the present invention, showing a section perpendicular to the axial direction of a permanent magnet synchronous motor using sector magnets 12. the

FIG. 18 is a perspective view showing a state where no layer skew is provided to the sector magnet 12 . the

FIG. 19 is a perspective view showing a state in which layer skew is provided to the sector magnet 12 (positions between magnetic poles are shifted) according to Embodiment 3 of the present invention. the

Even when the sector magnets 12 are used as shown in FIG. 19, by dividing the sector magnets 12 into two or more layers in the axial direction and shifting the sticking position between the magnetic poles in the axial direction, it is possible to achieve the same effect as in the first embodiment described above. Likewise, the 4f component of the cogging torque is sufficiently suppressed. the

Also in this case, the motor output characteristics of the permanent magnet synchronous motor with respect to the skew angle θ are as shown in FIG. 16 , and the motor output characteristics are improved similarly to the case of the ring magnet 11 . the

14 to 19 show the case where the number of magnetic poles of the ring magnet 11 or the sector magnet 12 (rotor 1) is 10 poles, but it is not limited to this, and it can also be equal to Z/{3 (phase) × The value of 2P} is 2/7 and the rotor 1 with 14 poles is combined to form a motor structure with 14 poles and 12 slots. the

As mentioned above, the permanent magnet synchronous motor according to Embodiment 3 of the present invention (Fig. 1, Fig. 14, Fig. 19) has: Z (Z is a natural number) stator slots 21 formed in an annular shape and applied with windings; The rotor 1 in the annular shape of the stator slot 21; and the annular magnet 11 or sector magnet 12 (permanent magnet) of 2P poles (P is a natural number) that is integrally formed with the rotor and arranged opposite to the stator slot 21, and constituted as The value of Z/{3(phase)×2P} is 2/5 or 2/7. the

On the surface of the ring magnet 11 or the sector magnet 12 facing the stator slot 21 , at least two or more layer skews are provided such that the electrical angle is 42° to 128° with respect to the axial direction of the rotor 1 . the

As a result, the 4f component of the cogging torque can be sufficiently suppressed similarly to Embodiments 1 and 2 described above, and it is also possible to achieve continuous skew with the above-mentioned setting like the motor output characteristics ( FIG. 16 ) in layer skew. The reduction of the fundamental wave is reduced compared to the case, and therefore, the output characteristics can also be improved. the

(Example 4)

In Embodiment 3 above (Fig. 14 and Fig. 19), layer skew is formed by using two layers of ring magnets 11 or sector magnets 12, but it can also be constructed as shown in Fig. 20 and Fig. 21: using three layers of ring magnets 11a to 11c Alternatively, the sector magnets 12a to 12c form layer skews in such a manner that they are in a symmetrical relationship through the central portion, and the start position and end position of the skew angle θ with respect to the rotation direction of the rotor 1 are the same as in the second embodiment described above. . the

Fig. 20 (Fig. 21) is a perspective view showing the rotor 1 and the ring magnet 11 (sector magnet 12) of the permanent magnet synchronous motor according to Embodiment 4 of the present utility model. Detailed description is omitted. In addition, the overall structure of Embodiment 4 of the present invention is as shown in FIG. 1 . the

In FIG. 20 ( FIG. 21 ), the rotational positions of the ring magnets 11 a and 11 c (sector magnets 12 a and 12 c ) at both ends in the axial direction of the ring magnet 11 (sector magnet 12 ) are set to be the same. the

In addition, the rotational position of the ring magnet 11 b (sector magnet 12 b ) at the central portion in the axial direction is shifted by the skew angle θ from the magnets at both end portions. the

In addition, the lengths Ha and Hc of the ring magnets 11 a and 11 c (sector magnets 12 a and 12 c ) at both ends in the respective axial directions are set to the same value, and the sum of the magnet lengths at both ends (Ha+Hc) is equal to It is set to the same value as the magnet length Hb of the ring magnet 11b (sector magnet 12b ) in the center. the

Thereby, while reliably suppressing the 4f component of the groove torque, like the second embodiment described above, the thrust in the axial direction due to the skew in the state where the motor current is passed and the load is applied can be eliminated. the

In particular, by setting the sum (Ha+Hc) of the magnet lengths at both ends to the same value as the magnet length Hb in the center, it is possible to reliably cancel the thrust. the

In addition, in Fig. 20 and Fig. 21, the case where the number of magnetic poles of the ring magnet 11 or the sector magnet 12 (rotor 1) is 10 poles is shown, but it is not limited thereto. ) × 2P} value of 2/7 of the 14-pole rotor 1 combination, a 14-pole 12-slot motor structure. the

In addition, the layers constituting the three layers here are skewed, but they can also be composed of any number of (2n+1) layers (n is a natural number), as long as the start position and end position of the skew angle are the same. the

(Example 5)

In addition, in the above-mentioned Embodiments 1 to 4 (Fig. 7 to Fig. 21), in order to suppress the 4f component of the cogging torque, a skew was provided on the rotor 1 side, but as shown in Fig. 22 to Fig. 33, the The stator 2 side (stator slot 21) is provided with a skew. the

In this case, as the rotor 1 , for example, a configuration in which no skew is provided may be applied (see FIGS. 6 and 18 ). In addition, the overall structure of Embodiment 5 of the present invention is as shown in FIG. 1 . the

22 to 33 show the stator slot 21 according to Embodiment 5 of the present invention, and FIG. 22 is a cross-sectional view showing the cross-sectional shape of the axial end of one tooth of the stator slot 21 provided with continuous skew. the

In addition, FIG. 23 is a cross-sectional view showing the cross-sectional shape of the lower end portion in the axial direction of one tooth of the stator slot 21 in the case where continuous skew is provided. the

FIG. 24 is a perspective view showing one tooth of the stator slot 21 having the upper and lower cross-sectional shapes of FIGS. 22 and 23 (the front side and the rear side in the axial direction). the

In FIG. 24 , one tooth shape of the stator slot 21 is continuously skewed by changing only the tooth end surface in the axial direction, and has the same skew angle θ as described above. the

25 is a perspective view showing the inner surface structure of the stator 2 produced by arranging a plurality of teeth of FIG. 24 , and FIG. 26 is a developed view showing the tooth end surface shape of the stator slot 21 of FIG. 25 in plan. the

In the permanent magnet type synchronous motor employing the stator slots 21 shown in FIGS. 22 to 26 , the relationship of the cogging torque with respect to the skew angle θ is as shown in the aforementioned FIG. 8 . the

In addition, even when continuous skew is provided to the stator slot 21 (stator 2 ) as shown in FIGS. 22 to 26 , as shown in FIG. The upper surface (near) side and the lower surface (deep) side are set at the same position and the tooth position of the central part is shifted, thereby canceling the thrust generated on the rotor 1 due to the skew. the

In FIG. 27 , the tooth end faces are in a positional relationship in which the upper end side and the lower end side in the axial direction are at the same position, and the tooth central portion is at a different position. the

FIG. 28 is a developed view planarly showing the shape of the end surface of the stator slot 21 in FIG. 27 . the

In addition, in FIGS. 22 to 28 , the stator slots 21 are provided with a continuous skew, but as shown in FIGS. 29 to 33 , the stator slots 21 may be provided with a layered skew. the

FIG. 29 is a perspective view showing one tooth of the stator slot 21 provided with layer skew, showing a state in which the shape of the tooth end surface changes in the center portion of the tooth. the

In FIG. 29, the tooth end surfaces of the stator slots 21 have a point-symmetrical shape with respect to the axial direction after the central portion of the tooth. the

30 is a perspective view showing the inner surface structure of the stator slot 21 in which a plurality of teeth of FIG. 29 are arranged, and FIG. 31 is a developed view showing the end surface shape of the stator slot 21 of FIG. 30 in plan. the

In FIG. 30 , each tooth of the stator slot 21 is formed in the same shape up to the central portion in the axial direction, and therefore, there is no need to have a plurality of dies. the

As shown in FIGS. 30 and 31 , even when the shape of the center portion and end surface of each tooth changes, the 4f component of the cogging torque with respect to the skew angle θ can be sufficiently suppressed as described above. the

In addition, in the case where the stator slot 21 is provided with layer skew as shown in FIGS. The shape that the positional relationship of the central part changes. the

In FIG. 32 , the end faces of the teeth of the stator slots 21 are in the following positional relationship: the upper side and the lower side in the axial direction are at the same position, and the central parts of the teeth are at different positions. the

FIG. 33 is a developed view planarly showing the formation of the end surface of the stator slot 21 of FIG. 32 . the

Even in the permanent magnet synchronous motor using the stator 2 shown in FIGS. 31 to 33 , the effect of suppressing the 4f component of the cogging torque can be obtained as described above. the

In addition, by forming the stator shape shown in FIG. 32 , it is possible to cancel the thrust generated on the rotor 1 due to the skew. the

As described above, the permanent magnet synchronous motor according to Embodiment 5 of the present invention (Fig. 1, Fig. 6, Fig. 18, Fig. 22 to Fig. 33) includes: Z (Z is a natural number) formed in an annular shape and applied with windings ) the stator slot 21; the rotor 1 arranged in the annular shape of the stator slot 21; and the annular magnet 11 or sector magnet 12 of 2P poles (P is a natural number) which is integrally formed with the rotor 1 and arranged opposite to the stator slot 21 ( permanent magnet), and the value of Z/{3 (phase) × 2P} is 2/5 or 2/7. the

The tip shape of the stator slot 21 facing the ring magnet 11 or the sector magnet 12 is provided with a continuous or layered skew with an electrical angle of 42° to 128° relative to the axial direction of the rotor 1 . the

Thus, by providing the skewed structure on the end surface of the stator slot 21, the 4f component of the cogging torque can be sufficiently suppressed as described above. the

In addition, when skew is also provided on the rotor 1 side, it is possible to suppress another component of the cogging torque, and also to reduce the cogging torque. the

In addition, as shown in FIG. 32 , by setting the start position and end position of the skew angle to be the same with respect to the rotation direction of the rotor 1 in the continuous skew or layer skew, generation of thrust can be suppressed. the

Label description

1: rotor, 2: stator, 3: frame, 11, 11a~11c: ring magnet, 12, 12a~12c: sector magnet, 21: stator slot, 31: inner diameter part, θ: skew angle. the

Claims (6)

1. permanent-magnet synchronous electric motor, it possesses:

Z stator slot, this stator slot shape become circular and are applied with winding, and Z is natural number;

Rotor, this rotor configuration is in described stator slot circular; With

2P utmost point permanent magnet, this permanent magnet and described rotor one consist of and configure opposed to each other with described stator slot, and P is natural number,

Described permanent-magnet synchronous electric motor is take the Z/{3(phase) * value of 2P} consists of as 2/5 or 2/7 mode,

Described permanent-magnet synchronous electric motor is characterised in that,

In described permanent magnet and opposed faces described stator slot, being provided with electrical degree is the continuous skews of 42 degree ~ 128 degree with respect to the direction of principal axis of described rotor.

2. permanent-magnet synchronous electric motor as claimed in claim 1, is characterized in that,

Described continuous skew is configured to: the starting position of the axial skew angle of described rotor is identical about the direction of rotation of described rotor with end position.

3. permanent-magnet synchronous electric motor, it possesses:

Z stator slot, this stator slot shape become circular and are applied with winding, and Z is natural number;

Rotor, this rotor configuration is in a described Z stator slot circular; With

2P utmost point permanent magnet, this permanent magnet and described rotor one consist of and configure opposed to each other with described stator slot, and P is natural number,

Described permanent-magnet synchronous electric motor is take the Z/{3(phase) * value of 2P} consists of as 2/5 or 2/7 mode,

Described permanent-magnet synchronous electric motor is characterised in that,

In described permanent magnet and opposed faces described stator slot, with respect to the direction of principal axis of the described rotor modes as 42 degree ~ 128 degree, be provided with the layer skew more than at least 2 layers take electrical degree.

4. permanent-magnet synchronous electric motor as claimed in claim 3, is characterized in that,

Described layer skew is made of the 2n+1 layer, and it is identical about the direction of rotation of described rotor with end position to be configured to the starting position of skew angle, and n is natural number.

5. permanent-magnet synchronous electric motor, it possesses:

Z stator slot, this stator slot shape become circular and are applied with winding, and Z is natural number;

Rotor, this rotor configuration is in a described Z stator slot circular; With

2P utmost point permanent magnet, this permanent magnet and described rotor one consist of and configure opposed to each other with described stator slot, and P is natural number,

Described permanent-magnet synchronous electric motor is take the Z/{3(phase) * value of 2P} consists of as 2/5 or 2/7 mode,

Described permanent-magnet synchronous electric motor is characterised in that,

To with the end shape of the opposed described stator slot of described permanent magnet, being provided with electrical degree is continuous skews or the layer skew of 42 degree ~ 128 degree with respect to the direction of principal axis of described rotor.

6. permanent-magnet synchronous electric motor as claimed in claim 5, is characterized in that,

Described continuous skew or described layer skew are configured to: the starting position of skew angle is identical about the direction of rotation of described rotor with end position.

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