JP2007288903A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor which averages the rigidity of a stator as a whole in a circumferential direction when each magnet is firmly adhered to a yoke, while facilitating assembling by alternately arranging a plurality of magnets with gaps therebetween, and can suppress vibration at rotation-driving. <P>SOLUTION: In the yoke 2, a reinforcing part (attachment part 23) increased in thickness in the radial direction is arranged in a zone longer than the gap toward circumferential both sides in a position which corresponds to the gap between each magnet 5 in the yoke 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor having a magnet on the inner peripheral surface of a yoke.

Conventionally, for example, there is an electric motor in which a magnet is arranged as illustrated in FIG. On the inner peripheral surface of the cylindrical yoke of this electric motor, an arc-shaped magnet having a central angle of 120 ° is magnetized with the inner peripheral surface on one end side as the N pole and the inner peripheral surface on the other end side as the S pole. Three fixed in the direction without any gaps. An attachment portion for fixing the motor is provided on the outer periphery of the yoke where the magnetic pole that becomes the antinode of vibration changes, so that vibration associated with rotation of the rotor is suppressed.
JP 2006-34089 A

  However, according to the above magnet arrangement, each magnet is arranged along the inner circumferential surface of the yoke without any gap in the circumferential direction. Therefore, if the magnet and the yoke are not processed with high accuracy, each magnet is assembled to the yoke. There was a problem that could not.

  Therefore, as shown in FIG. 5, in order to facilitate the assembly of the magnet 101 to the yoke 100, it is considered that the magnets 101 are spaced apart in the circumferential direction on the inner peripheral surface of the yoke 100 to provide a gap. It is done. However, when a gap is provided between the magnets 101, the rigidity of the stator as a whole is reduced as compared with a case where the magnet 101 is arranged without a gap. Therefore, vibration (noise) at the time of rotational driving tends to occur.

  The present invention has been made in view of such circumstances, and its purpose is to arrange a plurality of magnets with gaps between them to facilitate assembly and fix these magnets to a yoke. It is an object of the present invention to provide an electric motor that can average the rigidity of the entire stator in the circumferential direction and suppress vibration during rotational driving.

  In order to solve the above-described problem, the invention according to claim 1 is a stator in which a plurality of arc-shaped magnets are fixed in the circumferential direction along the inner peripheral surface of a cylindrical yoke with a gap therebetween. In the electric motor, a section that is longer on both sides in the circumferential direction than the gap and a reinforcing portion that is thick in the radial direction are provided at positions corresponding to the gaps between the magnets in the yoke.

  According to this configuration, the yoke is provided with a section that is longer on both sides in the circumferential direction than the gap and a reinforcing portion that is thicker in the radial direction at positions corresponding to the gaps between the magnets. The ends of the magnets to be fitted are fixed to one reinforcing part with an overlap in the radial direction. By the way, when the magnets are arranged apart from each other in the circumferential direction so as to provide a gap between the magnets, the portion of the yoke where the magnet is not fixed is more resistant to the radial load than the portion of the yoke where the magnet is fixed on the inner peripheral side. Stiffness is reduced. For this reason, when a gap is provided between the magnets, vibration during rotation driving is larger than that in which the magnet is provided without a gap in the circumferential direction. According to the present invention, the reinforcing portions are provided in the section yokes that are longer on both sides in the circumferential direction than the gaps at positions corresponding to the gaps between the magnets, thereby separating the magnets in the circumferential direction so as to provide gaps between the magnets. The reduction in rigidity due to the arrangement can be compensated. Therefore, while arranging a plurality of magnets with a gap between them to facilitate assembly, the rigidity of the entire stator when the magnets are fixed to the yoke is averaged in the circumferential direction, and vibration during rotation drive is achieved. Can be suppressed.

According to a second aspect of the present invention, the reinforcing portion is provided on the outer peripheral side of the yoke.
According to this configuration, by providing the reinforcing portion on the outer peripheral side of the yoke, the circumferential position of the magnet fixed on the inner peripheral side of the yoke can be confirmed from the outside, and the yoke is fixed by the reinforcing portion. Positioning can be performed with respect to the member.

According to a third aspect of the present invention, in the electric motor according to the first or second aspect, the reinforcing portion also serves as an attachment portion for fixing the yoke and the other member.
According to this configuration, the reinforcing portion is provided as a portion that also serves as the attachment portion, and thus does not need to be provided as a reinforcing portion. Further, the yoke shape is not complicated.

  According to a fourth aspect of the present invention, in the electric motor according to the third aspect, the reinforcing portion includes an insertion hole for inserting a fastening member, the diameter of the insertion hole being the length of the gap. It is set equally.

  According to this configuration, since the diameter of the insertion hole provided in the reinforcing portion is set to be equal to the length of the gap between the magnets, the position of the magnet with respect to the yoke can be recognized by the insertion hole. Therefore, it is possible to prevent the magnet from being fixed at an incorrect position with respect to the yoke and the magnetized position of the magnet fixed to the yoke from being erroneously magnetized.

  According to a fifth aspect of the present invention, in the electric motor according to any one of the first to fourth aspects, the magnet includes at least two magnetic pole portions and a non-magnetic pole portion provided between the magnetic pole portions. And the angle range of the gap is set to be equal to the angle range of the non-magnetic pole portion.

  According to this configuration, since a plurality of magnetic poles are formed by one magnet, it is necessary when forming the same number of poles on the inner periphery of the yoke as compared to the case where one magnetic pole is formed by one magnet. It is possible to reduce the number of magnets. Therefore, the number of parts can be reduced, and the assembly of the magnet to the yoke can be facilitated. In addition, the number of gaps between the magnets can be reduced, and the number of low rigidity portions can be reduced. Therefore, it is possible to reduce the number of places where the reinforcing portion is required, and the yoke shape is not complicated.

  Further, the invention according to claim 6 is the electric motor according to any one of claims 1 to 5, wherein the number of the magnets is an odd number, and each of the plurality of magnets has a predetermined angular interval in the circumferential direction. And an even number of magnetic pole portions having different polarities alternately.

  According to this configuration, magnetic poles having different polarities alternately formed at equal angular intervals in the circumferential direction are formed on the stator by an odd number of magnets having an even number of magnetic pole portions having different polarities alternately at predetermined angular intervals in the circumferential direction. Is done. By the way, the natural vibration mode of the cylindrical stator is provided with an even number of nodes (antinodes) at equal angles in the circumferential direction. Therefore, at least one of the plurality of magnets continues in the circumferential direction corresponding to the position of the antinode of vibration induced in the stator. Therefore, by forming an even number of magnetic poles with an odd number of magnets, the rigidity can be increased in accordance with the position of the antinode of vibration induced in the stator. Therefore, the vibration induced in the stator can be suppressed as a whole by increasing the rigidity of the stator corresponding to the position of the antinode of the vibration.

  According to the present invention, while arranging a plurality of magnets with a gap between them to facilitate assembly, the rigidity of the entire stator when the magnets are fixed to the yoke is averaged in the circumferential direction and rotated. An electric motor that can suppress vibration during driving can be provided.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, a DC motor 1 as an electric motor is provided with a bottomed cylindrical yoke 2, and an end cap 3 is fixed to a screw 4 as a fastening member in the opening. An odd number (5 in this embodiment) of magnets 5 are fixed to the inner peripheral surface of the yoke 2. A bearing holding portion 2a is formed at the center of the bottom of the yoke 2, and a bearing 6 is provided inside the bearing holding portion 2a. In addition, a bearing 7 is provided substantially at the center of the end cap 3.

  An armature 8 is accommodated in the yoke 2. An output shaft 9 of the armature 8 is rotatably supported by bearings 6 and 7 and has a tip projecting from the end cap 3 to the outside. The armature 8 includes an armature core 10 fixed to the output shaft 9 and a 24-segment commutator 11, and a winding 12 wound around the armature core 10 is electrically connected to the commutator 11. Has been.

  A brush device 13 is fixed to the inner side surface of the end cap 3 with screws 14. The brush device 13 holds a brush 15 that is in sliding contact with the commutator 11. The end cap 3 is assembled with a power feeding unit 16. The power supply unit 16 supplies power to the brush 15 from the outside. Then, power is supplied from the power supply unit 16 to the armature winding 12 via the brush 15, the commutator 11, and the shorting member 11 a attached to the winding 12 side of the commutator 11. The output shaft 9 rotates with respect to the stator (yoke 2 and magnet 5).

  Next, the arrangement structure of the magnets 5 in the yoke 2 will be described. For simplification of the drawing, the bearing holding portion 2a provided at the center of the bottom of the yoke 2 is omitted in FIG.

  The yoke 2 includes a cylindrical portion 21 (see FIG. 1) formed in a substantially cylindrical shape. As shown in FIG. 2, five magnets 5 are arranged on the inner peripheral surface of the cylindrical portion 21 at equal intervals in the circumferential direction. Each magnet 5 is formed to have a substantially arc-shaped cross section having an outer surface 5 a along the inner peripheral surface of the yoke 2. Each magnet 5 is formed slightly shorter than the length obtained by dividing the inner peripheral surface of the yoke 2 into five equal parts in the circumferential direction, and a gap is provided between the magnets 5 adjacent to each other in the circumferential direction. That is, the range of the angle of the gap between the magnets 5 adjacent to each other in the circumferential direction is α, and the range of the angle of the circumferential length of the magnet 5 along the inner peripheral surface of the yoke 2 is β. Assuming that the number of magnets 5 is γ, the yoke 2 is formed such that (α + β) × γ = 360 °.

  Each magnet 5 is provided with an even number of magnetic pole portions 51 and 52 having different polarities alternately at predetermined angular intervals in the circumferential direction. More specifically, in each magnet 5, a magnetic pole portion 51 that is magnetized so that the inner peripheral surface side is an N pole is formed at one circumferential end, and the inner peripheral surface side is S at the other circumferential end. A magnetic pole portion 52 magnetized so as to be a pole is formed, and each of the magnets 5 is provided with two magnetic pole portions 51 and 52. Each magnet 5 is provided with a non-magnetic pole portion 53 that is not magnetized between the magnetic pole portions 51 and 52. The non-magnetic pole portion 53 is set to an angle range α1 equivalent to the angle range α of the gap between the magnets 5, and the magnetic pole portions 51 and 52 magnetized in the N pole and the S pole in each magnet 5, respectively. The angle range is set to be equal. That is, on the inner periphery of the yoke 2, an even number (10 pieces) of magnetic poles are provided at equal angular intervals (36 ° intervals) in the circumferential direction by an odd number (5 pieces) of magnets 5.

  The yoke 2 is provided with a section that is longer on both sides in the circumferential direction than the gap and a reinforcing portion that is thick in the radial direction at a position corresponding to the gap between the magnets 5 in the yoke 2. More specifically, a flange 22 is formed in the opening of the yoke 2. The flange portion 22 extends radially outward from the opening, and is formed in a substantially annular shape that is coaxial with the cylindrical portion 21 when viewed from the axial direction. Further, the flange portion 22 is provided with five attachment portions 23 as reinforcement portions at equal angular intervals in the circumferential direction. The attachment portion 23 is formed by extending the outer peripheral surface of the flange portion 22 radially outward in a substantially triangular shape, and the yoke 2 is thick in the radial direction. The mounting portion 23 is formed such that a section L1 in which the mounting portion 23 is provided in the circumferential direction is longer on both sides in the circumferential direction than a circumferential length L2 along the inner peripheral surface of the gap of the magnet 5. The end portions of the magnets 5 that are adjacent to each other in the circumferential direction fixed to the inner peripheral side of the magnet 2 overlap in the radial direction. Further, an insertion hole 24 for fixing the end cap 3 provided in the opening of the yoke 2 is formed in the attachment portion 23 so as to penetrate in the axial direction. The insertion hole 24 has a diameter (circumferential width) D equivalent to the circumferential length L2 of the gap between the magnets 5. The end cap 3 is fixed to the opening of the yoke 2 in which the magnet 5 and the armature 8 are accommodated by the screw 4 inserted through the insertion hole 24.

  Here, as shown in FIG. 2, in the yoke 2, the rigidity of the portion where the attachment portion 23 is provided with respect to the radial load is higher than the rigidity of the portion where the attachment portion 23 is not provided. In the yoke 2, the rigidity of the portion 22a where the magnet 5 is fixed on the inner peripheral side is such that the magnet 5 is not fixed on the inner peripheral side, that is, the portion 22b where a gap is provided between the magnets 5 in the circumferential direction. It becomes higher than rigidity. Therefore, when a gap is provided between the magnets 5, for example, when the magnet 101 is fixed so that the gap of the magnet 101 is arranged in a portion where the attachment portion 100 a is not provided as shown in FIG. 5, the gap is arranged. The rigidity of the portion 100b is lowered.

  In the present embodiment, the mounting portion 23 is provided on the section yoke 2 that is longer on both sides in the circumferential direction than the gap at a position corresponding to the gap between the magnets 5 in the yoke 2. The rigidity of the portion 22b whose rigidity is lower than that of the portion 22a to which the magnet 5 is fixed is increased. Therefore, a decrease in rigidity caused by providing a gap between the magnets 5 is suppressed.

As described above, the present embodiment has the following effects.
(1) Since a section longer on both sides in the circumferential direction than the gap and a mounting portion 23 having a thickness in the radial direction are provided at positions corresponding to the gaps between the magnets 5 in the yoke 2, they are adjacent to each other in the circumferential direction. The ends of the matching magnets 5 are fixed to one mounting portion 23 with an overlap in the radial direction. By the way, when the magnets 5 are arranged apart from each other in the circumferential direction so as to provide a gap between the magnets 5, the portion of the yoke 2 where the magnets 5 are not fixed is more than the portion of the yoke 2 where the magnets 5 are fixed on the inner peripheral side. However, the rigidity against the load in the radial direction is lowered. For this reason, when a gap is provided between the magnets 5, vibration during rotation driving is larger than when the magnet 5 is provided without a gap in the circumferential direction. According to the present invention, the magnets are provided so as to provide a gap between the magnets 5 by providing the mounting portions 23 on the section yoke 2 that is longer on both sides in the circumferential direction than the gap at a position corresponding to the gap between the magnets 5 in the yoke 2. It is possible to compensate for a decrease in rigidity caused by disposing 5 in the circumferential direction. Therefore, the rigidity of the entire stator (yoke 2 and magnet 5) when the magnets 5 are fixed to the yoke 2 is determined while arranging a plurality of magnets 5 with a gap therebetween to facilitate assembly. By averaging in the direction, vibration during rotational driving can be suppressed.

  (2) By providing the mounting portion 23 on the outer peripheral side of the yoke 2, the circumferential position of the magnet 5 fixed on the inner peripheral side of the yoke 2 can be confirmed from the outside, and the yoke 2 can be attached by the mounting portion 23. Positioning can be performed with respect to the member to be fixed.

  (3) Since the reinforcing portion is provided as the mounting portion 23 for fixing the end cap 3, it is not necessary to provide the reinforcing portion specially as the reinforcing portion. Further, the shape of the yoke 2 is not complicated.

  (4) Since the diameter D of the insertion hole 24 provided in the attachment portion 23 as the reinforcing portion is set to be equal to the length of the gap between the magnets 5, the position of the magnet 5 relative to the yoke 2 is recognized by the insertion hole 24. It becomes possible to do. Therefore, it is possible to prevent the magnet 5 from being fixed at an incorrect position with respect to the yoke 2 and the magnetized position of the magnet 5 fixed to the yoke 2 from being magnetized by mistake.

  (5) Since a plurality of magnetic poles are formed by one magnet 5, it is necessary when forming the same number of poles on the inner circumference of the yoke 2 compared to the case where one magnet 5 forms one magnetic pole. Therefore, the number of magnets 5 can be reduced. Therefore, the number of parts can be reduced, and the assembly of the magnet 5 to the yoke 2 can be facilitated. In addition, the number of gaps between the magnets 5 can be reduced, and the portion having low rigidity can be reduced. Therefore, it is possible to reduce the number of places where the reinforcing portion is required, and the shape of the yoke 2 is not complicated.

  (6) By an odd number of magnets 5 having even number of magnetic pole portions 51 and 52 having different polarities alternately at predetermined angular intervals in the circumferential direction, the stator (yoke 2 and magnet 5) is equiangularly spaced in the circumferential direction. Magnetic poles having different polarities are alternately formed. By the way, the natural vibration mode of the cylindrical stator (yoke 2 and magnet 5) is provided with an even number of nodes (antinodes) at equal angles in the circumferential direction. Therefore, at least one of the plurality of magnets 5 continues in the circumferential direction corresponding to the position of the antinode of vibration induced in the stator (yoke 2 and magnet 5). Therefore, by forming an even number of magnetic poles with an odd number of magnets 5, it is possible to increase the rigidity corresponding to the position of the antinode of vibration induced in the stator (yoke 2 and magnet 5). Therefore, the vibration induced in the stator (yoke 2 and magnet 5) can be suppressed as a whole by increasing the rigidity of the stator (yoke 2 and magnet 5) corresponding to the position of the antinode of the vibration.

In addition, you may change embodiment of this invention as follows.
-In the above-mentioned embodiment, although the reinforcement part is provided only in the opening part of the yoke 2 as the attaching part 23 of the collar part 22, it is not limited to such an aspect. For example, as shown in FIGS. 3 (a) and 3 (b), the reinforcing portion is pivoted on the outer peripheral surface of the cylindrical portion 21 of the yoke 2 so as to correspond to the position of the gap of the magnet 5 provided on the inner peripheral side of the yoke 2. Ribs 25 extending in the direction may be provided together.

  In the above embodiment, the 10-pole DC motor 1 including the five magnets 5 is used. However, the present invention is not limited to this mode. For example, as shown in FIG. The present invention may be applied to a 6-pole DC motor in which three magnets 5 having magnetic poles are fixed.

  In the above embodiment, the end cap 3 is fixed to the attachment portion 23 as the reinforcing portion. However, the embodiment is not limited to such an embodiment. For example, the direct current is applied to the driven body driven by the direct current motor 1. It may also be used as a configuration for fixing or positioning the motor 1.

  -In the said embodiment, although the reinforcement part is provided in the outer peripheral side of the yoke 2, it is not limited to such an aspect, For example, the thick part formed by extending the inner peripheral surface of the yoke 2 to radial inside May be provided as a reinforcing portion. In this case, the outer surfaces of both ends of the magnet 5 are recessed inward in the radial direction as necessary.

  In the above embodiment, the magnet 5 is provided with the non-magnetic pole portion 53 and the two magnetic poles are formed by one magnet 5. However, the present invention is not limited to this mode. Magnetic poles may be formed, and three or more magnetic poles may be formed by one magnet 5.

  In the above embodiment, the brushed DC motor 1 is shown as the electric motor. However, the present invention may be applied to motors other than the brushed DC motor.

Schematic of the DC motor according to the present embodiment. The top view which shows the magnet arrangement | positioning which concerns on this Embodiment. (A) The perspective view of the other example of this Embodiment, (b) Partial sectional drawing of another example. The top view which shows the magnet arrangement | positioning of another example of this Embodiment. The top view which shows the conventional magnet arrangement | positioning.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2,100 ... Yoke (stator), 3 ... End cap (other member), 4 ... Screw (fastening member), 5,101 ... Magnet (stator), 5a ... Outer surface, 23, 100a ... Mounting part (reinforcement) Part), 24 ... insertion hole, 51, 52 ... magnetic pole part, 53 ... non-magnetic pole part, D ... diameter of the insertion hole, L1 ... circumferential length (section) of the attachment part (reinforcing part), L2 ... circumference of the gap Directional length, α: range of gap angle, α1: range of non-magnetic pole angle.

Claims (6)

A motor having a stator in which a plurality of arc-shaped magnets are circumferentially fixed along the inner peripheral surface of a cylindrical yoke, and are fixed with a gap therebetween,
An electric motor characterized in that at a position corresponding to the gap between each of the magnets in the yoke, there are provided a section that is longer on both sides in the circumferential direction than the gap and a reinforcing portion that is thick in the radial direction.   The electric motor according to claim 1, wherein the reinforcing portion is provided on an outer peripheral side of the yoke.   The electric motor according to claim 1, wherein the reinforcing portion also serves as an attachment portion for fixing the yoke and another member. The reinforcing portion includes an insertion hole for inserting a fastening member,
The electric motor according to claim 3, wherein a diameter of the insertion hole is set to be equal to a length of the gap. The magnet includes at least two magnetic pole portions and a non-magnetic pole portion provided between the magnetic pole portions,
5. The electric motor according to claim 1, wherein the electric motor is set to be equal to an angle range of the gap and an angle range of the non-magnetic pole portion.   6. The magnet according to claim 1, wherein the number of magnets is an odd number, and each of the plurality of magnets includes an even number of magnetic pole portions having different polarities alternately at predetermined angular intervals in the circumferential direction. The electric motor according to item 1.

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