JP2012080715A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor that reduces cogging torque.SOLUTION: A motor includes: a plurality of magnet sections 21 and 22 with alternately arranged polarities; and a plurality of teeth 32 that project so as to face the plurality of magnet sections 21 and 22 and that are configured so as to be movable relative to the magnet sections 21 and 22. A tip end of each of the teeth 32 has a magnetic field line leakage promoting portion 132 that allows leakage of magnetic field lines, guided to the tip end of each of the teeth 32, from permanent magnets 21A and 22A, in areas 122 of a rotor 2 where polarities of the permanent magnets 21A and 22A are switched.

Description

  The present invention relates to a motor such as a linear motor or a rotary motor.

  2. Description of the Related Art Conventionally, there has been known a motor including a plurality of magnet portions arranged so that the polarities are switched and a plurality of teeth protruding so as to face the plurality of magnet portions and configured to be relatively movable with the magnet portions. (For example, refer to Patent Document 1).

JP 2007-259513 A (see FIGS. 3 and 4)

  In such a motor, in a region where the polarities of adjacent magnet portions are switched, attraction or repulsion between the teeth and one magnet portion is switched to repulsion or attraction between the other magnet portion. Cogging occurs at the time of switching, but cogging is preferably eliminated or suppressed because it pulsates the output torque of the motor.

  However, in the motor of Patent Document 1, since both side surfaces in the width direction (circumferential direction) of the umbrella portion formed at the tip portion of the tooth are small, the lines of magnetic force guided from the magnet portion to the tip portion of the tooth are saturated at the umbrella portion. As a result, the density of the magnetic field lines at the tip of the teeth becomes dense. Therefore, the attraction force between the tip portion of the teeth and the magnet portion is increased, and cogging is increased. As a result, it is difficult to obtain a stable output torque of the motor.

  Accordingly, the present invention has been made in view of such circumstances, and an object of the invention is to provide a motor that can suppress cogging and obtain a stable output torque.

  That is, in order to solve the above-described problems, the motor of the present invention is configured to be capable of moving relative to the plurality of magnet portions, which are alternately arranged in polarity, projecting so as to face the plurality of magnet portions. A plurality of teeth, and a leading portion of the teeth is formed with a leakage magnetic force line promoting portion for leaking the magnetic force lines led from the magnet portion in a region where the polarities of adjacent magnet portions are switched. It is said.

  According to the above configuration, since the leakage magnetic force line promoting portion that leaks the magnetic force line guided from the magnet portion to the tip portion of the tooth is formed, the lead portion is guided to the tip portion in the region where the polarities of the adjacent magnet portions are switched. Magnetic field lines can be actively leaked, and the magnetic flux density at the tip can be made sparse. Therefore, the attractive force (or repulsive force) between the teeth and the magnet portion can be reduced, and the cogging can be reduced.

  Further, in the motor of the present invention, the leakage magnetic force line promoting portion includes both side surfaces in the width direction orthogonal to the protruding direction of the teeth, and the size of the both side surfaces is set according to the amount of the magnetic force lines to be guided. It may be.

  Further, in the motor of the present invention, the leakage magnetic force line promoting portion includes both side surfaces in the width direction perpendicular to the protruding direction of the teeth, and the both side surfaces have a large air gap between the teeth and the magnet portion. The size may be set accordingly.

  According to the present invention, since the leakage magnetic force line promoting portion for leaking the magnetic force lines from the magnet portion guided to the tip portion of the teeth is formed, the polarity is introduced to the tip portion in the region where the polarities of the adjacent magnet portions are switched. As a result of actively leaking the magnetic lines of force and reducing the magnetic flux density at the tip, it is possible to provide a motor that can suppress cogging and obtain a stable output torque.

It is a cross-sectional view of the motor according to the present invention. It is an enlarged view of the principal part of FIG. It is an enlarged view of the principal part of the motor provided with the permanent magnet of another shape. It is a cross-sectional view of the motor which shows the front-end | tip part of the teeth of another shape. It is a cross-sectional view of the motor showing the tip of the tooth of another shape (A), (b), (c) is a cross-sectional view which shows the front-end | tip part of the teeth of another shape.

  Hereinafter, a brushless motor which is an example of a motor according to the present invention will be described with reference to the drawings. As shown in FIG. 1, this brushless motor has a rotor (movable element) 2 that rotates around the axis of the motor shaft 1 that is a rotating shaft, and a narrow gap (air gap G) that surrounds the outer periphery of the rotor 2. And a stator (stator) 3 fixed to a casing (not shown). This brushless motor is used as a load device (for example, a magnet dynamo for a test device) for applying an accurate load to the motor in order to perform a load test of a motor mounted on a hybrid vehicle or an electric vehicle. You may use as a motor mounted in a car, an electric vehicle, etc., and you may use for another purpose.

  The rotor 2 has a first magnet portion 21 arranged so that the N pole faces outward in a range that is substantially half of the outer circumferential surface of the motor shaft 1 (upper half in the figure), and the remaining half range. And a second magnet portion 22 arranged so that the south pole faces outward. The first magnet portion 21 is formed by integrating a plurality of (for example, 10) permanent magnets 21A arranged along the circumferential direction so that the north pole faces outward, with a slight gap or without a gap. The second magnet portion 22 has a plurality of (for example, ten) permanent magnets 22A arranged along the circumferential direction so that the south pole faces outward, with a slight gap or no gap. It is constructed integrally.

  The stator 3 includes an annular yoke 31 positioned on the outer side, and a plurality of (for example, 24) teeth 32 that project radially from the inner peripheral surface of the yoke 31 toward the motor shaft 1. The gap between the adjacent teeth 32 and 32 is referred to as a slot 33 and is provided in the same number as the number of teeth 32.

  A winding (not shown) is wound around each tooth 32. By supplying power to the winding, a magnetic field is generated in the stator 3, and this magnetic field and the first and second magnet portions 21 and 22 are generated. The rotor 2 is rotated by the interaction with the magnetic field lines from.

  The teeth 32 include a teeth body 32A that extends radially inward from the yoke 31 and a tip portion 32B that extends further radially inward from the tip of the teeth body 32A and is integrated.

  The teeth main body 32A is configured in a plate shape, and has a substantially rectangular shape in plan view extending inward in the radial direction with the same width. Moreover, as shown in FIG.1 and FIG.2, in the front-end | tip part 32B, the leakage magnetic force line | wire acceleration | stimulation part 132 is formed, and in the area | region where the polarity of adjacent magnet parts 21,21 (, 22,22) switches, A function of leaking the magnetic lines of force guided from the magnet unit 21 to the tip 32B of the tooth 32 is provided. The leakage magnetic force line promoting portion 132 includes a tip surface 132c facing the magnet portions 21 and 22, a pair of both side surfaces 132a and 132b extending radially outward from both widthwise ends of the tip surface 132c, and both side surfaces 132a and 132b. And wedge portions 132d and 132d that connect the tip of the teeth body 32A.

  The front end surface 132c is a flat surface extending in a direction substantially orthogonal to the longitudinal direction of the teeth 32, and both side surfaces 132a and 132b are tapered surfaces that extend in the radial direction and are further away from the radially outer side and closer to the radially inner side. It is configured. Note that both side portions of the distal end surface 132c slightly protrude outward in the width direction from both side portions of the teeth main body 32A. That is, the width (dimension in the circumferential direction) of the front end surface 132c is wider than the width of the teeth body 32A. Further, the wedge portions 132d and 132d have a triangular shape that is cut obliquely and becomes narrower toward the teeth main body 32A side. A gap between the tip surface 132c and the outer peripheral surfaces 21a and 22a of the magnet portions 21 and 22 is an air gap.

  The width of the front end surface 132c is determined by the amount of magnetic flux (induced voltage value). Therefore, by changing (optimizing) the amount of magnetic flux and the size (length) of the air gap, the width of the tip surface 132c can be determined. Next, an example in which the width of the distal end surface 132c is specifically set will be described.

  Both side surfaces 132a and 132b are set in size according to the number of magnetic lines of magnetic force (magnetic flux amount) guided to the leakage magnetic field line promoting part 132. For example, the length dimension (more specifically, the length dimension of both side surfaces 132a and 132b) of the distal end portion 32B of the tooth 32 is L1, and the width dimension (more specifically, the distal end surface) of the distal end portion 32B of the tooth 32. When the width dimension of 132c is L2, L1 and L2 are set so as to satisfy 0.5 <L1 / L2 <1. That is, the leakage magnetic force line promoting portion 132 is set such that the length dimension L1 of the teeth 32 is larger than 0.5 and smaller than 1 with respect to the width dimension L2 of the teeth 32.

  The reason is that the magnetic lines of force from the magnet parts 21 and 22 guided through the front end surface 132c of the leakage magnetic force line promoting portion 132 escape through both side surfaces 132a and 132b in the width direction of the leakage magnetic force line promoting portion 132. When it is possible to do so, all the lines of magnetic force can be leaked by half from both side surfaces. If it is set to be larger than 0.5, which is half, the magnetic field lines can be surely leaked from both side surfaces 132a and 132b, and the magnetic field lines from the permanent magnet 21A or 22A The width dimension L of the tooth 32 (of the tip portion 32B) when it can be escaped only from one of the side surfaces 132a and 132b in the direction. By setting the (tip portion 32B) the length L1 of the teeth 32 in the same size with respect to, because it is possible to leak reliably magnetic field lines even only on one side 132a or 132b. Therefore, the leakage magnetic force line promoting portion 132 is made to flow from the both side surfaces 132a and 132b of the leakage magnetic force line promoting portion 132 or from one surface 132b (or 132a) so that the amount of the magnetic force lines guided from the magnet portions 21 and 22 to the teeth 32 is flowed. By setting, the magnetic flux density can be effectively sparse.

  Moreover, the magnitude | size is set according to the magnitude | size of the air gap G between the teeth 32 and the magnet parts 21 and 22 on both the side surfaces 132a and 132b. That is, as the air gap G becomes smaller, the magnetic resistance in the air gap G becomes smaller, so that the magnetic lines of force from the magnet parts 21 and 22 are more easily transmitted to the leakage magnetic field line promoting part 132. For this reason, the length of the leakage magnetic force line promoting portion 132 is lengthened, that is, the length dimension L1 of the tooth 32 (of the tip end portion 32B) is the same as the width dimension L2 of the tooth 32 (the tip end portion 32B) as described above. By adjusting to the dimension side, a large amount of magnetic field lines can be surely leaked. On the other hand, the larger the air gap G, the greater the magnetic resistance in the air gap G, so that the magnetic lines of force from the magnet parts 21 and 22 are less likely to be transmitted to the leakage magnetic field line promoting part 132. Therefore, the length of the leakage magnetic force line promoting portion 132 is shortened, that is, as described above, the length dimension L1 of the tooth 32 (of the tip end portion 32B) is half of the width dimension L2 of the tooth 32 (of the tip end portion 32B). If the adjustment is made to the side of 0.5, the length of the tooth 32 (of the tip portion 32B) can be shortened, but a small amount of magnetic field lines can be surely leaked.

  FIG. 2 shows a state in which a region (boundary portion) 122 where the NS magnetic poles of the magnet portions 21 and 22 of the rotor 2 are switched reaches one of the adjacent teeth 32. In this state, three magnetic lines 4A, 4B, 4C out of the four magnetic lines 4A, 4B, 4C, 4D emitted from the permanent magnet 21A of the one magnet portion 21 guided to one of the teeth 32 are leaked magnetic lines. It leaks from one side 132b of the width direction both sides 132a and 132b of the promotion part 132, and leaks to 22A of permanent magnets 22A of the other magnet part 22. FIG. The magnetic lines 4D that have not leaked move to the adjacent teeth 32 via the yoke 31 and return to the other permanent magnet 22A. Further, in each of the teeth 32 or 32 positioned on both sides in the circumferential direction of the two adjacent teeth 32, 32, the magnetic lines of force 4 E, 4 E from the permanent magnet 21 A are passed from one tooth 32 through the yoke 31 to the other tooth 32. To return to the permanent magnet 22A.

  As described above, the leakage magnetic force line promoting portion 132 actively leaks, that is, the leakage magnetic force line promoting portion 132 forms a magnetic path in which the magnetic force lines flow from the front end surface 132c toward the side surface 132b, and is guided from the front end surface 132c. Since the magnetic field lines are guided along the magnetic path and leaked from the side surface 132b, the magnetic flux density of the magnetic field lines at the tip 32B where the leakage magnetic field line promoting part 132 is formed can be made sparse. The suction force (or repulsive force) acting between the teeth 32 can be reduced. As a result, it is possible to realize the motor 1 that can suppress cogging acting on the rotor 2 (magnets 21A, 22A) and can obtain a stable output torque.

  Since the size of the side surfaces 132a and 132b of the leakage magnetic force line promoting portion 132 is set according to the amount of the magnetic force lines to be guided and the size of the gap G, it is possible to reliably leak without enlarging the tip portion 32B unnecessarily. There is an advantage that cogging can be effectively suppressed.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  In the above-described embodiment, the first magnet portion 21 is composed of 10 permanent magnets 21A (permanent magnets with the N pole facing outward), and 10 permanent magnets 22A (permanent magnets with the S pole facing outward). As shown in FIG. 3, the first magnet unit 21 is composed of one permanent magnet 21B (permanent magnet with the N pole facing outward), as shown in FIG. You may comprise the 2nd magnet part 22 from permanent magnet 22B (permanent magnet which S pole becomes outward). In this case, it is preferable to form both ends in the circumferential direction of the permanent magnets 21B and 22B on tapered surfaces 21T and 22T which are obliquely dropped. By adopting such tapered surfaces 21T and 22T, in the region 122, the air gap G becomes larger toward the end portions in the circumferential direction of the magnet portions 21 and 22, and between the permanent magnets 21B and 22B and the teeth 32 in the region 122. This increases the magnetic resistance, thereby suppressing the attractive force (or repulsive force) and suppressing cogging.

  Moreover, in the said embodiment, although the both sides | surfaces of the leakage magnetic force line promotion part 132 were made into a plane, as shown in FIG. 4, the protrusion 132F of one or more (4 pieces in the figure) protrusion 132F was formed in the both sides of the leakage magnetic force line promotion part 132. Alternatively, as shown in FIG. 5, the side surfaces can be made uneven by providing one or more pointed heads on the both side portions. In this case, since the area of both side surfaces 132a and 132b can be increased, there is an advantage that the radial dimension of the tip portion can be reduced and the teeth 32 can be reduced in size. 4 and 5, the leakage magnetic force line promoting portion 132 becomes wider from the tip end surface 132c toward the teeth main body 32A, but it may be the same width.

  In the above embodiment, the wedge portions 132d and 132d that are obliquely cut are provided on both sides on the outer peripheral side (yoke 31 side) of the leakage magnetic force line promoting portion 132. However, as shown in FIG. The parts 132d and 132d can be omitted. In FIG. 6A, the leakage magnetic force line promoting portion 132 has the same width from the tip end surface 132c thereof to the teeth main body 32A. That is, both side surfaces 132 a and 132 b of the leakage magnetic force line promoting portion 132 are flat along the protruding direction of the teeth 32. Moreover, you may comprise the magnetic force line promotion part 132 as shown in FIG.6 (b), (c). In FIG. 6B, the leakage magnetic force line promoting portion 132 of FIG. 4 is configured to have the same width from the tip end surface 132c to the teeth main body 32A, and a single (in the figure, one is present) on both sides of the leakage magnetic force line promoting portion 132. However, a plurality of point heads 132T may be provided. Further, in FIG. 6C, the leakage magnetic force line promoting portion 132 is configured to have the same width from the front end surface 132c to the teeth body 32A, and is recessed toward the front end side at the outer peripheral side (yoke 31 side) end of the magnetic force line promoting portion 132. The structure provided with a pair of recessed parts 132K and 132K is shown.

  Moreover, although the inner type brushless motor was shown in the said embodiment, an outer type brushless motor may be sufficient and various linear motors may be sufficient.

  In the above embodiment, a motor having two poles and 24 slots is shown. However, the present invention is not limited to this, and various motors having freely set poles and slots may be used. Good.

  Moreover, in the said embodiment, although the square-shaped permanent magnet was used, you may use the hook-shaped permanent magnet from which the corner | angular of the both ends of the circumferential direction was taken.

  Moreover, in the said embodiment, although all the teeth 32 were equipped with the leakage magnetic force line promotion part 132, it can also be made to equip some teeth 32 with the leakage magnetic force line promotion part 132, and can implement.

  DESCRIPTION OF SYMBOLS 1 ... Motor shaft, 2 ... Rotor, 3 ... Stator, 4A, 4B, 4C ... Magnetic field line, 21, 22 ... Magnet part, 21A, 21B, 22A, 22B ... Permanent magnet, 21T ... Tapered surface, 21a, 22a ... Outer peripheral surface , 31 ... Yoke, 32 ... Teeth, 33 ... Slot, 122 ... Region, 132 ... Leakage magnetic force line promotion part, 132K, 132K ... Recess, 132T, 132T ... Projection, 132a, 132b ... Both sides in the width direction, 132a, 132b ... Both sides Surface, G ... Air gap

Claims (3)

A plurality of magnet portions alternately arranged in polarity, and a plurality of teeth protruding so as to face the plurality of magnet portions and configured to be relatively movable with the magnet portion,
The motor is characterized in that a leakage magnetic force line accelerating portion for leaking magnetic force lines introduced from the magnet portion is formed at a tip portion of the tooth in a region where the polarities of adjacent magnet portions are switched.   The leakage magnetic force line promoting portion includes both side surfaces in a width direction perpendicular to the protruding direction of the teeth, and the both side surfaces are sized according to the amount of the magnetic force lines to be guided. Item 4. The motor according to Item 1.   The leakage magnetic force line promoting portion includes both side surfaces in the width direction orthogonal to the protruding direction of the teeth, and the both side surfaces are set according to the size of the air gap between the teeth and the magnet portion. The motor according to claim 1, wherein the motor is provided.

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