JP5313752B2 - Brushless motor - Google Patents

Description

  The present invention relates to a brushless motor in which a magnetic pole portion in which a permanent magnet is accommodated in a rotor core and an iron core portion of the rotor core are alternately arranged in the circumferential direction.

  2. Description of the Related Art Conventionally, a brushless motor having a so-called embedded magnet type rotor in which a plurality of magnet housing portions penetrating in the axial direction of a rotor core constituting a rotor are formed in the circumferential direction, and permanent magnets are respectively disposed in the magnet housing portions. It is known (see, for example, Patent Document 1).

  The rotor of Patent Document 1 is disposed on the radially inner side of the stator, and a plurality of permanent magnets disposed in the circumferential direction have the same magnetic pole on the outer side in the circumferential direction (S pole in Patent Document 1). It is arranged to become. In this rotor, the core part on the radially outer surface side of the rotor core between the permanent magnets in the circumferential direction functions as a magnetic pole (N pole) different from the magnetic pole (S pole) on the radially outer side of the permanent magnet. It is configured as a rotor with a structure.

JP 2004-201406 A

  By the way, in the brushless motor rotor as described above, when the permanent magnet is inserted into each magnet accommodating portion formed in the rotor core, the magnet accommodating portion and the permanent magnet are dimensional tolerances of the magnet accommodating hole to facilitate the insertion. And it is formed in consideration of the dimensional tolerance of the permanent magnet. Therefore, a gap (gap) is easily formed between the permanent magnet and the magnet housing hole, and the permeance (reciprocal of the magnetic resistance) is reduced by the radial gap that is the direction of the magnetic flux passing through the permanent magnet and the iron core. Thus, the magnetic flux generated by the permanent magnet cannot be effectively used. For this reason, the output performance is lowered, and improvement of these problems is desired.

  The present invention has been made to solve the above problems, and an object thereof is to provide a brushless motor capable of improving output performance.

In order to solve the above problems, the invention according to claim 1 is a stator formed by winding a winding around a tooth, and a rotor provided rotatably with a plurality of magnetic pole portions facing each of the teeth. The rotor is inserted and arranged in a plurality of magnet housing portions formed at equal intervals in the circumferential direction of the rotor core so that the same magnetic pole surface of the permanent magnet faces the teeth, and the magnetic pole portions The brushless motor is formed with an iron core portion through which the magnetic flux of each magnetic pole portion passes in the radial direction by forming a gap that becomes a magnetic resistance between both magnetic pole portions. A magnetic member is inserted and disposed in the magnet housing portion so as to fill a gap between the magnetic pole surface of the permanent magnet and the magnet housing portion, and the magnetic member has a width of the permanent magnet to suppress eddy current. Split in direction and axial direction As its gist in that it is constituted by a block-shaped plurality of members.

  In this invention, since the magnetic member is inserted and arranged in the magnet housing portion so as to fill the gap between the magnetic pole surface of the permanent magnet and the magnet housing portion, the gap between the magnet housing portion and the permanent magnet can be easily formed by the magnetic member. It can be narrowed. And since it is a magnetic member, the magnetic flux of a permanent magnet can be passed suitably, the magnetic flux amount by the side of an iron core part increases, and it becomes possible to improve the output performance as a motor. Further, since the gap can be narrowed by the magnetic member, it is possible to suppress the rattling of the permanent magnet.

Further, since the magnetic member is composed of a plurality of members, the generation of eddy current can be easily suppressed.
The invention according to claim 2 is the brushless motor according to claim 1, wherein the magnetic member is made of an electromagnetic steel plate.
In this way, by using an electromagnetic steel sheet, which is a member having a low magnetic loss, which is the sum of hysteresis loss and eddy current loss, as iron, which has high permeability among ferromagnetic elements, output performance is achieved. It can contribute to improvement.
Invention of Claim 3 is equipped with the stator which winds a coil | winding to teeth, and the rotor which has a some magnetic pole part which opposes each said teeth, and is provided rotatably, In the said rotor, A plurality of magnet receiving portions formed at equal intervals in the circumferential direction of the rotor core are inserted and disposed so that the same magnetic pole surface of the permanent magnet faces the teeth, and the magnetic pole portions are formed, and the magnetic pole portions are formed between the magnetic pole portions. Is a brushless motor in which an iron core portion through which the magnetic flux of each magnetic pole portion passes in the radial direction is formed by forming a gap that becomes a magnetic resistance at both ends of each magnetic pole portion, and the magnet housing portion includes The gist is that a magnetic member is inserted and arranged to fill a gap between the magnetic pole surface of the permanent magnet and the magnet housing portion, and the magnetic member is made of a ferromagnetic damping alloy.
In this invention, since the magnetic member is inserted and arranged in the magnet housing portion so as to fill the gap between the magnetic pole surface of the permanent magnet and the magnet housing portion, the gap between the magnet housing portion and the permanent magnet can be easily formed by the magnetic member. It can be narrowed. And since it is a magnetic member, the magnetic flux of a permanent magnet can be passed suitably, the magnetic flux amount by the side of an iron core part increases, and it becomes possible to improve the output performance as a motor. Further, since the gap can be narrowed by the magnetic member, it is possible to suppress the rattling of the permanent magnet. Moreover, the vibration which may generate | occur | produce with rotation of a rotor can be suppressed by comprising a magnetic member from a ferromagnetic type damping alloy.
The gist of the invention described in claim 4 is the brushless motor according to claim 3, wherein the magnetic member has a slit or a plurality of members to suppress eddy current. .
In this invention, since the slit is formed in the magnetic member or the magnetic member is composed of a plurality of members, generation of eddy current can be easily suppressed.
According to a fifth aspect of the present invention, in the brushless motor according to any one of the first to fourth aspects, the rotor is disposed radially inside the stator, and the magnetic member is The gist thereof is that the permanent magnet is inserted and disposed so as to be in contact with the radially inner magnetic pole surface.

  In the present invention, the rotor is disposed on the radially inner side of the stator. The magnetic member is inserted and disposed so as to contact the magnetic pole surface on the radially inner side of the permanent magnet. By adopting such a configuration, it is possible to leave a slight gap in the radial direction between the magnetic pole surface on the radially outer side of the permanent magnet and the magnet housing portion, for example, while improving the magnetic flux path to the iron core portion. In addition, the generation of so-called eddy currents that can occur outside in the radial direction can be suppressed, and deterioration of output performance due to eddy current loss can be suppressed.

The invention described in 請 Motomeko 6, in a brushless motor according to any one of claims 1 to 5, wherein the magnetic member, the permanent magnet-side surface of the magnetic member from the pole face of the permanent magnet The gist is that it is configured in a large manner.

  In this invention, the magnetic member is configured such that the surface of the magnetic member on the permanent magnet side is larger than the magnetic pole surface of the permanent magnet. For this reason, when the permanent magnet and the magnetic member are accommodated (arranged) in the magnet accommodating portion, the magnetic pole surface of the permanent magnet can be more reliably covered with the magnetic member. It is possible to pass through to the side suitably. For this reason, it becomes possible to improve the output performance as a motor more.

  Therefore, according to the above described invention, it is possible to provide a brushless motor capable of improving the output performance.

The schematic block diagram of the motor in this embodiment. Explanatory drawing for demonstrating arrangement | positioning of the permanent magnet and magnetic member in the same as the above. The graph which showed the comparison with the motor of this embodiment, and the conventional motor. (A) (b) is explanatory drawing for demonstrating arrangement | positioning of the permanent magnet and magnetic member in another example. (A) (b) is explanatory drawing for demonstrating arrangement | positioning of the permanent magnet and magnetic member in another example. The schematic block diagram of the rotor in another example. The schematic block diagram of the rotor in another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of the brushless motor of the present embodiment. The brushless motor 10 according to the present embodiment is capable of rotating on a stator 14 formed by winding a winding 13 around a plurality of teeth 12 extending radially inward from an annular portion 11 and on the radially inner side of the stator 14. And a rotor 15 provided on the motor.

  The stator 14 is housed in a motor housing (not shown), and includes 12 teeth 12 and windings 13 wound around each of the teeth 12. The winding 13 is composed of three phases of U, V, and W phases, and is configured to be normally wound in the order of the U phase, the W phase, and the V phase in the clockwise direction. The windings 13 wound around the teeth 12 are energized with a three-phase (U / V / W phase) alternating current.

The rotor 15 includes a rotor core 21 fixed to the rotary shaft 20 so as to be rotatable integrally with the rotary shaft 20 on the radially outer side of the rotary shaft 20 that is rotatably supported by a bearing (not shown).
The rotor core 21 has a substantially cylindrical shape, and a plurality of magnetic pole portions 22 facing the teeth 12 on the stator 14 side are formed on the outer peripheral edge of the rotor core 21.

  As shown in FIG. 2, the magnetic pole portion 22 has a permanent magnet 24 and a plurality of (in this embodiment) a housing hole 23 as a magnet housing portion formed in a mode of penetrating along the axial direction on the radially outer side of the rotor core 21. 2) magnetic steel plates 25 and 26 as magnetic bodies are accommodated. That is, the brushless motor 10 of this embodiment is configured as a so-called IPM motor having a permanent magnet embedded rotor 15. The receiving holes 23 are formed at regular intervals (90 ° intervals) in the circumferential direction.

  Each permanent magnet 24 is arranged in each accommodation hole 23 so that the radially outer surface thereof has the same polarity (S pole in this embodiment). Thereby, in the rotor 15 of the present embodiment, four magnetic pole portions 22 having the same polarity (S pole) are formed at equal intervals (90 ° intervals) along the circumferential direction.

  The plurality of electromagnetic steel plates 25 and 26 inserted (accommodated) in the accommodation hole 23 are arranged so that one of the electromagnetic steel plates 25 is in surface contact with the magnetic pole surface 24a (N pole side surface) on the radially inner side of the permanent magnet 24. In addition, the other electromagnetic steel plate 26 is disposed so as to be in surface contact with the radially inner plate surface 25 a of the electromagnetic steel plate 25 in surface contact with the permanent magnet 24. Further, the electromagnetic steel plates 25 and 26 have a length in the width direction (the length in the left-right direction in FIG. 2) longer than the width direction length of the permanent magnet 24 and shorter than the width direction length of the accommodation hole 23. Is set to a large size. Thereby, it is possible to easily cover the permanent magnet 24 with the electromagnetic steel plates 25 and 26.

  Asymmetrical gaps 30 and 31 are formed at both ends in the circumferential direction of the magnetic pole portion 22 configured as described above. Since each of these air gaps 30 and 31 serves as a magnetic resistance, an iron core portion 32 magnetically partitioned from each magnetic pole portion 22 in the circumferential direction is formed between the magnetic pole portions 22.

  That is, the magnetic flux of each magnetic pole part 22 flows into each iron core part 32 via the inside of the rotor core 21 so as to bypass each gap 30 and 31 formed at both ends in the circumferential direction. Then, when the magnetic flux passes through each iron core portion 32 toward the outside in the radial direction, each of the iron core portions 32 has a pseudo magnetic pole having a polarity different from that of the adjacent magnetic pole portion 22 (in this embodiment, radially outside). N poles) are formed. That is, the rotor 15 of the present embodiment is configured as a so-called contiguous pole type rotor. For this reason, the usage-amount of the permanent magnet 24 can be reduced in half. Of the asymmetrical gaps 30, 31, one of the gaps 30 is formed to have a larger shape than the other gap 31, so that it is optimal for rotation in one direction (counterclockwise in FIG. 1). It has become a structure.

  In the brushless motor 10 configured as described above, the rotating shaft 20 is rotated together with the rotor 15 by energizing the winding 13 with a three-phase alternating current. At this time, as described above, the permanent magnet 24 and the electromagnetic steel plates 25 and 26 as magnetic members are inserted into the accommodation hole 23. For this reason, since the gap (air gap) between the magnetic pole surface 24a on the radially inner side of the permanent magnet 24 and the receiving hole 23 is narrowed by the electromagnetic steel plates 25 and 26, the magnetic flux generated from the magnetic pole surface 24a on the radially inner side is generated by the iron core portion 32. It can be suitably passed to the side.

  Here, the inventor performed a simulation to show the effectiveness of the present embodiment. In this simulation, when the thickness of the permanent magnet 24 is 2.25 mm and the radial gap between the permanent magnet 24 and the accommodation hole 23 is 0.335 mm, the electromagnetic steel plates 25 and 26 having a thickness of about 0.1 mm are formed. Two sheets (thickness gauge of about 0.2 mm) are set as insertion conditions. When the simulation is performed under such conditions, the induced voltage of the conventional brushless motor having a gap of 0.335 mm is increased to about 106.1% in the brushless motor of this embodiment, assuming that the induced voltage amount is 100%. (See FIG. 3). That is, it can be said that the permeance is improved by inserting the electromagnetic steel plates 25 and 26 and the induced voltage is increased because the effective magnetic flux is increased. For this reason, by inserting and arranging the electromagnetic steel plates 25 and 26 between the permanent magnet 24 and the accommodation hole 23 as in this embodiment, the effective magnetic flux increases and the output performance as the motor 10 can be improved. .

  Further, by inserting and arranging one of the electromagnetic steel plates 25 and 26 so as to contact the magnetic pole surface 24a on the radially inner side of the permanent magnet 24, for example, the magnetic pole surface 24b on the radially outer side of the permanent magnet 24 and Since it is possible to leave a slight gap in the radial direction with respect to the housing hole 23, it is possible to suppress the generation of so-called eddy currents that can occur outside in the radial direction, and to suppress deterioration in output performance due to eddy current loss. it can. In addition, as a magnetic member that fills the radial gap between the permanent magnet 24 and the accommodation hole 23, it is iron having high permeability among ferromagnetic elements, and so-called iron loss that is the sum of hysteresis loss and eddy current loss. By using the electromagnetic steel plates 25 and 26 which are members having a small amount, the output performance as the motor 10 can be improved.

Next, characteristic actions and effects of the present embodiment will be described.
(1) Since the magnetic steel plates 25 and 26 as magnetic members are inserted and arranged in the accommodation hole 23 as the magnet accommodation portion so as to fill the radial gap between the magnetic pole surface 24a of the permanent magnet 24 and the accommodation hole 23, The radial gap between the accommodation hole 23 and the permanent magnet 24 can be easily narrowed by the electromagnetic steel plates 25 and 26. And since the electromagnetic steel plates 25 and 26 are magnetic members, the magnetic flux of the permanent magnet 24 can be suitably passed, and the amount of magnetic flux on the iron core portion 32 side is increased, so that the output performance as the motor 10 can be improved. It becomes possible. In addition, since the gap can be narrowed by the electromagnetic steel plates 25 and 26, it is possible to suppress the rattling of the permanent magnet 24 in the radial direction.

  (2) The rotor 15 is disposed on the radially inner side of the stator 14. The electromagnetic steel plate 25 is inserted and disposed so as to contact the magnetic pole surface 24 a on the radially inner side of the permanent magnet 24. By adopting such a configuration, it is possible to leave a slight gap in the radial direction between, for example, the magnetic pole surface 24a on the radially outer side of the permanent magnet 24 and the accommodation hole 23 while improving the magnetic flux path to the iron core portion 32. Therefore, the generation of so-called eddy currents that can occur on the outside in the radial direction can be suppressed, and deterioration of the output performance of the motor 10 due to eddy current loss can be suppressed.

  (3) The electromagnetic steel plates 25 and 26 are configured such that the surface of the electromagnetic steel plates 25 and 26 on the permanent magnet 24 side is larger than the magnetic pole surface 24 a of the permanent magnet 24. For this reason, when the permanent magnet 24 and the electromagnetic steel plates 25 and 26 are accommodated (arranged) in the accommodation hole 23, the magnetic pole surface 24a of the permanent magnet 24 can be covered with the electromagnetic steel plates 25 and 26 more reliably. The magnetic flux generated from the magnet 24 can be suitably passed to the iron core 32 side. For this reason, it becomes possible to improve the output performance as the motor 10 more.

  (4) By using magnetic steel sheets 25 and 26 which are irons having a high magnetic permeability among ferromagnetic elements and a so-called low iron loss member, which is the sum of hysteresis loss and eddy current loss, as magnetic members. This can contribute to the improvement of output performance as the motor 10.

The embodiment of the present invention may be modified as follows.
In the above embodiment, two electromagnetic steel plates 25 and 26 as magnetic members are provided, but one or three or more may be used. In short, it may be configured to fill the radial gap between the permanent magnet 24 and the accommodation hole 23 with an electromagnetic steel plate.

  In the above embodiment, the magnetic pole surface (a magnetic pole surface on the N pole side) 24a in the radial direction of the permanent magnet 24 and the magnetic steel plate 25 as the magnetic member are in contact with each other. The magnetic pole member (S pole side magnetic pole surface) 24b may be in contact with the magnetic member. Further, the permanent magnet 24 may be sandwiched between a plurality of magnetic members.

  In the above embodiment, although not particularly mentioned, the gap between the magnetic pole surface 24 a and the accommodation hole 23 can be filled more reliably by press-fitting the electromagnetic steel plates 25 and 26 into the accommodation hole 23.

  -In above-mentioned embodiment, although the electromagnetic steel plates 25 and 26 as a magnetic member were comprised by the plate-shaped member, you may comprise a magnetic member (electromagnetic steel plates 25 and 26) by the aggregate | assembly of a some member. For example, as shown in FIGS. 4A and 4B, a configuration in which a plurality of strip-like magnetic members 40 and 41 divided in the width direction of the permanent magnet 24 (left and right in the drawing) may be employed. Further, as shown in FIGS. 5A and 5B, a configuration in which a plurality of block-like magnetic members 50 divided in the width direction and the axial direction (perpendicular to the paper surface) of the permanent magnet 24 may be employed. Thus, by comprising a magnetic member with a some member, an eddy current can be suppressed and an eddy current loss can be suppressed.

  In the above embodiment, although not specifically mentioned, slits may be formed in the electromagnetic steel plates 25 and 26 as magnetic members. With such a configuration, eddy current can be suppressed and eddy current loss can be suppressed.

  In the above-described embodiment, each magnetic pole portion 22 is formed using the flat permanent magnet 24, but is not limited thereto. For example, as shown in FIG. 6, each magnetic pole portion 60 may be embodied by a curved plate-like permanent magnet 61. Further, as shown in FIG. You may actualize in the structure which forms each magnetic pole part 66 by arrange | positioning in letter shape. In such a configuration, the magnetic member 75 that is in surface contact (contact) with the magnetic pole surfaces 61a and 65a of the permanent magnets 61 and 65 is disposed in order to fill the gaps between the accommodation holes 70 and the permanent magnets 61 and 65. Thus, the same effect as in the above embodiment can be obtained. In the case of a curved permanent magnet 61 as shown in FIG. 6, it is desirable to dispose a magnetic member formed following the curved shape.

  In the above embodiment, in the motor 10 having a so-called 8-pole 12-slot configuration, the winding 13 is configured to be wound in the clockwise direction in the order of the U phase, the W phase, and the V phase. . For example, in a motor with 10 poles and 12 slots, the windings are clockwise W phase (forward winding), bar W phase (reverse winding), bar V phase, V phase, U phase, bar U phase, bar W phase, W phase. , V phase, bar V phase, bar U phase, U phase, and so on. Even in this case, by applying the present invention, the induced voltage increases, and the output performance as a motor can be improved.

  -In the said embodiment, although the magnetic member was comprised with the electromagnetic steel plates 25 and 26, it is not restricted to this. For example, the magnetic member may be made of a ferromagnetic damping alloy. By configuring the magnetic member with a ferromagnetic damping alloy in this way, vibration that can occur as the rotor 15 rotates can be suppressed.

In the above embodiment, the gaps 30 and 31 between the magnetic pole part 22 and the iron core part 32 are configured to be asymmetrical, but may be symmetrical.
In the above embodiment, the inner rotor type brushless motor is configured so that the rotor 15 is rotatably disposed inside the stator 14. However, an outer rotor type brushless motor may be used.

  DESCRIPTION OF SYMBOLS 10 ... Brushless motor, 12 ... Teeth, 13 ... Winding, 14 ... Stator, 15 ... Rotor, 21 ... Rotor core, 22, 60, 66 ... Magnetic pole part, 23 ... Accommodating hole as magnet accommodating part, 24, 61, 65 ... permanent magnets, 24a, 24b, 61a, 65a ... magnetic pole surfaces, 25, 26 ... magnetic steel sheets as magnetic members, 30, 31 ... gaps, 32 ... iron cores, 40, 41, 50, 75 ... magnetic members.

Claims (6)

A stator formed by winding a winding around a tooth, and a rotor provided rotatably with a plurality of magnetic pole portions facing each of the teeth,
In the rotor, each magnetic pole part is formed by being arranged so that the same magnetic pole surface of a permanent magnet faces the teeth in each magnet housing part formed at equal intervals in the circumferential direction of the rotor core, Between each of the magnetic pole parts, a brushless motor in which an iron core part through which the magnetic flux of each magnetic pole part passes in a radial direction is formed by forming a gap that becomes a magnetic resistance at both ends of each magnetic pole part,
In the magnet housing portion, a magnetic member is inserted and arranged to fill a gap between the magnetic pole surface of the permanent magnet and the magnet housing portion ,
The brushless motor , wherein the magnetic member is composed of a plurality of block-shaped members divided in the width direction and the axial direction of the permanent magnet in order to suppress eddy currents . The brushless motor according to claim 1 ,
The brushless motor, wherein the magnetic member is made of an electromagnetic steel plate. A stator formed by winding a winding around a tooth, and a rotor provided rotatably with a plurality of magnetic pole portions facing each of the teeth,
In the rotor, each magnetic pole part is formed by being arranged so that the same magnetic pole surface of a permanent magnet faces the teeth in each magnet housing part formed at equal intervals in the circumferential direction of the rotor core, Between each of the magnetic pole parts, a brushless motor in which an iron core part through which the magnetic flux of each magnetic pole part passes in a radial direction is formed by forming a gap that becomes a magnetic resistance at both ends of each magnetic pole part,
In the magnet housing portion, a magnetic member is inserted and arranged to fill a gap between the magnetic pole surface of the permanent magnet and the magnet housing portion,
The brushless motor is characterized in that the magnetic member is made of a ferromagnetic damping alloy. The brushless motor according to claim 3 ,
The magnetic member has a slit or is composed of a plurality of members in order to suppress eddy currents. In the brushless motor according to any one of claims 1 to 4 ,
The rotor is disposed radially inside the stator,
The brushless motor according to claim 1, wherein the magnetic member is inserted and disposed so as to contact only a magnetic pole surface on the radially inner side of the permanent magnet. In the brushless motor according to any one of claims 1 to 5 ,
The magnetic member is a brushless motor characterized in that the surface of the magnetic member on the permanent magnet side is larger than the magnetic pole surface of the permanent magnet.

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