JP2007330084A - Rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor allowing a permanent magnet to be easily assembled to a holder. <P>SOLUTION: A rotor 50 includes a rotating shaft 52, a cylindrically shaped rotating shaft 54 integrally engaged and firmly secured to the outer periphery of the rotating shaft 52, magnet holders 55 firmly secured to an outer peripheral surface of the rotating shaft 54, and permanent magnets 56 retained to the magnet holders 55. In a process to insert an insertion part 54a of the rotating shaft 54 into the magnet holders 55, the outer periphery of the insertion 54a of the rotating shaft 54 also slide contacts with the inner periphery of the magnet holders 55 and an inner periphery 56b of the permanent magnets 56. Consequently, for the permanent magnet 56, the inner peripheries 56b are pressed outwardly in a radial direction, and edges 56a at both sides abut against abutting surfaces 55g of the magnet holders 55, and thus protrusions 55h provided at the abutting surfaces 55g are elastically deformed. The permanent magnets 56 are press fitted into magnet insertion holes 55a to 55d respectively, and thus they are retained stably without rattling. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotor, and more particularly to a rotor configured to efficiently assemble a permanent magnet of a rotor incorporated in an inner rotor type brushless motor to a cylindrical holding member.

  The motor has a permanent magnet disposed on the stator side, a coil provided on the rotor side, and a brush motor that energizes the coil via a brush, and a brushless motor provided with a coil on the stator side and the permanent magnet disposed on the rotor side There is.

  Since the brushless motor has a configuration in which the brush is not slidably contacted with the commutator, it is possible to eliminate a failure due to a discharge phenomenon when the brush straddles between the commutators. However, in the inner rotor type brushless motor, a structure in which a stator having a coil wound around a core is fitted and fixed to the inner periphery of the case, and a permanent magnet held by a cylindrical holding member is integrally provided on the outer periphery of the rotor. It is.

  In a rotor incorporated in a conventional inner rotor type brushless motor, for example, a segment-shaped permanent magnet is attached to the rotor in a state of being held at a predetermined interval in the circumferential direction by a cylindrical holding member. In that case, a method of applying an adhesive to the permanent magnet and fixing it to the holding member is used. However, in the method of adhering the permanent magnet to the holding member, it is necessary to manage the cleaning process, the amount of adhesive applied, the drying time of the adhesive, etc. Manufacturing costs were also expensive.

In order to solve such a problem, as a fixing method not using an adhesive, for example, a plurality of magnet housing holes extending in the axial direction of the rotor core are provided, and segment-shaped permanent magnets are housed in the magnet housing holes. Method (for example, refer to Patent Document 1), or providing a V-shaped spacer arm on a cylindrical holding member, arranging a segment-shaped permanent magnet between the spacer arms, and covering the outer periphery with a cylindrical cover A method of holding each permanent magnet (for example, see Patent Document 2) has been considered.
Japanese Patent Laid-Open No. 2005-22395 Japanese Patent Laid-Open No. 2005-20887

  However, in the configurations described in Patent Documents 1 and 2, the gap (air gap) between the permanent magnet incorporated in the rotor and the core of the coil disposed outside the rotor is not the wall thickness of the magnet housing hole or the cover. There is a problem that the driving torque generated by the magnetic force between the permanent magnet and the coil decreases due to the increase in thickness.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a rotor that solves the above-described problems by fixing a segment-type permanent magnet without using an adhesive and bringing the permanent magnet close to a coil.

  In order to solve the above problems, the present invention has the following means.

  According to the present invention, in a rotor having a cylindrical holding member that holds a permanent magnet disposed inside a stator, a plurality of magnet insertion holes that penetrate from the inner periphery to the outer periphery in the circumferential direction of the holding member are formed at predetermined intervals. And it aims at solving the said subject by fitting the said rotary body to the inner periphery of the said holding member in the state which inserted the said permanent magnet from the inner side in the said magnet insertion hole.

  The magnet insertion hole preferably has a tapered contact surface that contacts the edge of the permanent magnet so that the inner peripheral opening is wide and the outer peripheral opening is narrow.

  It is desirable to provide an elastic portion that elastically contacts the edge of the permanent magnet on the contact surface of the magnet insertion hole.

  According to the present invention, a plurality of magnet insertion holes penetrating from the inner periphery to the outer periphery in the circumferential direction of the holding member are formed at predetermined intervals, and the permanent magnets are inserted into the magnet insertion holes from the inside, whereby the outer periphery of the permanent magnet is Since there is no covering member, the permanent magnet can be fixed to the holding member without using an adhesive, and it can be attached with the outer periphery of the permanent magnet exposed, and the driving efficiency of the generated torque can be reduced. It becomes possible to increase. Further, the number of magnetic poles of the rotor can be easily changed by changing the number of magnet insertion holes formed in the holding member.

  Further, according to the present invention, the contact surface that contacts the edge of the permanent magnet is formed in a tapered shape so that the inner peripheral opening of the magnet insertion hole is wide and the outer peripheral opening is narrow, so that when the rotor rotates. It is possible to prevent the permanent magnet from falling off due to the centrifugal force.

  Further, according to the present invention, since the elastic portion that elastically contacts the edge of the permanent magnet is provided on the contact surface of the magnet insertion hole, the magnet insertion hole is rotated with the permanent magnet inserted from the inside. When the elastic portion is elastically deformed and receives a pressing force when the body is fitted to the inner periphery of the holding member, the permanent magnet can be stably held in a state in which the magnet insertion hole does not rattle.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing an inner rotor type brushless motor to which an embodiment of a rotor according to the present invention is applied. As shown in FIG. 1, an inner rotor type brushless motor (hereinafter referred to as “motor”) 10 includes a housing 30 fixed to a bracket 20, a cylindrical case 40 supported by the housing 30, and the housing 30 and the case 40. And a stator 60 disposed on the outer circumferential side of the rotor 50.

  The rotor 50 includes a rotating shaft 52, a cylindrical rotating body 54 that is integrally fitted and fixed to the outer periphery of the rotating shaft 52, a magnet holder (holding member) 55 that is fixed to the outer peripheral surface of the rotating body 54, and And a segment-shaped permanent magnet 56 held by a magnet holder 55. The housing 30 holds a bearing 32 that rotatably supports one end of the rotary shaft 52. In addition, a bearing 42 that rotatably supports the other end of the rotary shaft 52 is held on the inner wall of the case 40. Accordingly, the rotor 50 has the rotating shaft 52 supported by the bearings 32, 42, and therefore, when a rotating torque is generated by the magnetic force between the permanent magnet 56 and the stator 60, the rotor 50 is rotated and connected to the rotating shaft 52. A drive mechanism (not shown) is driven.

  The stator 60 includes an annular core 62 disposed so that its inner peripheral surface is in close proximity to the outer peripheral surface of the permanent magnet 56, a three-phase coil 64 wound around the core 62, and shafts from both end surfaces of the core 62. And an insulator 66 extending in the direction. The core 62 has a configuration in which a plurality of annular metal plates made of a magnetic material are stacked, and is inserted into the internal space of the case 40.

  The insulator 66 is formed of a resin material, holds the coil 64 from the inner and outer periphery, and clamps the core 62 from both sides in the axial direction in the process of fixing the case 40 to the housing 30. The coil 64 is connected to a control circuit (not shown) via the connector 70.

  Therefore, when a current is supplied to the coil 64 of the stator 60 and the current supply to each phase is switched, a rotational torque is generated by the interaction between the magnetic force generated by the coil 64 and the magnetic force from the permanent magnet 56 of the rotor 50. In the motor 10 configured as described above, in order to further increase the driving torque at the time of rotational driving, it is desired to make the gap S (air gap) between the inner periphery of the core 62 and the outer periphery of the permanent magnet 56 as small as possible. Has been. Since the rotor 50 of the present invention is configured so that the outer periphery of the permanent magnet 56 is exposed, the outer periphery of the permanent magnet 56 can be brought closer to the core 62 because there is no cover or the like around the permanent magnet 56. Thus, the gap S can be made smaller than the conventional one (see Patent Documents 1 and 2 described above).

  2A and 2B are diagrams showing the magnet holder 55, where FIG. 2A is a side view, FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A, and FIG. 2C is an enlarged view of a portion A in FIG. is there. As shown in FIGS. 2A to 2C, the magnet holder 55 is formed of a resin material, and has a plurality of cylindrical circumferential positions (in this embodiment, four positions at intervals of 90 degrees). ) Are provided with magnet insertion holes 55a to 55d. That is, the magnet holder 55 is formed in a cage shape so as to surround the magnet insertion holes 55a to 55d, and is mounted between the pair of annular portions 55e formed at both ends in the axial direction and the pair of annular portions 55e. And four support portions 55f formed so as to extend in the axial direction.

  The support portions 55f surrounding the magnet insertion holes 55a to 55d are arranged at intervals of 90 degrees in the circumferential direction, and abut against the edge of the permanent magnet 56 so that the inner peripheral opening is wide and the outer peripheral opening is narrow. The contact surface 55g is formed in a taper shape. The contact surface 55g is provided with a plurality of protrusions 55h that function as elastic portions. The protrusion 55h is elastically deformed by the contact of the edge of the permanent magnet 56 and holds the permanent magnet 56 in a stable state without rattling.

  Since the magnet holder 55 can change the positions and the number of magnet insertion holes 55a to 55d by a resin molding die, the number of permanent magnets 56 can be set relatively easily even when the design of the motor 10 is changed. It is possible to change.

  FIG. 3 is a perspective view showing the shape of the permanent magnet 56. As shown in FIG. 3, the permanent magnet 56 has a cross section formed in an arc shape corresponding to the magnet insertion holes 55 a to 55 d, and both edge portions 56 a are formed in a tapered shape. That is, in the permanent magnet 56, the radius of curvature of the inner periphery 56 b is substantially the same as that of the inner periphery of the magnet holder 55, and the radius of curvature of the outer periphery 56 c is the same as that of the outer periphery of the magnet holder 55.

  Further, in the permanent magnet 56, the width Lb of the inner circumference 56b is the same as the width of the inner circumference opening of the magnet insertion holes 55a to 55d, and the width Lc of the outer circumference 56c is the width of the outer circumference opening of the magnet insertion holes 55a to 55d. It is formed in the same dimension as the dimension. The width Lb of the inner periphery 56b is wide and the width Lc of the outer periphery 56c is narrow (Lb> Lc).

  Further, the edge portions 56a on both sides are formed to be inclined at the same angle so as to correspond to the inclination angle of the contact surface 55g of the magnet holder 55. Furthermore, the total length Ld of the permanent magnet 56 in the axial direction is formed to be slightly shorter than the total length of the magnet insertion holes 55a to 55d. Therefore, when the permanent magnet 56 is inserted into the magnet insertion holes 55 a to 55 d from the inside, the outer periphery 56 c is mounted so as to be integrated with the outer periphery of the magnet holder 55.

  4A and 4B are views showing a state in which the permanent magnet 56 is attached to the magnet holder 55. FIG. 4A is a side view, and FIG. 4B is a cross-sectional view taken along the line CC in FIG. FIG. 5 is a longitudinal sectional view taken along line DD in FIG. 4A and 4B and FIG. 5, as the procedure 1 of the method for attaching the permanent magnet 56, first, the four permanent magnets 56 are inserted into the magnet insertion holes 55 a from the inner peripheral side of the magnet holder 55. Insert into each of ~ 55d. At that time, the inner periphery 56b of the permanent magnet 56 is on the inner side, and the outer periphery 56c is inserted in the magnet insertion holes 55a to 55d in the direction of the outer side.

  In the next procedure 2, a cylindrical rotating body 54 is inserted in the center of the magnet holder 55 in the axial direction. The end of the insertion portion 54a of the rotating body 54 has a chamfered shape, and can be easily inserted even when the inner periphery 56b of the permanent magnet 56 protrudes inward. In the process of inserting the insertion portion 54 a of the rotating body 54 into the magnet holder 55, the outer periphery of the insertion portion 54 a of the rotating body 54 is in sliding contact with the inner periphery of the magnet holder 55 and the inner periphery 56 b of the permanent magnet 56.

  Thereby, the inner periphery 56b of the permanent magnet 56 is pressed outward in the radial direction, and the edge portions 56a on both sides come into contact with the contact surface 55g of the magnet holder 55. Furthermore, since the protrusion 55h of the contact surface 55g is elastically deformed by the press-fitting of the permanent magnet 56, the permanent magnet 56 is protected from being broken by a load during press-fitting.

  In this manner, the permanent magnet 56 is press-fitted into each of the magnet insertion holes 55a to 55d, so that the permanent magnet 56 is stably held without rattling. In the rotor 50, since the permanent magnet 56 is held in the magnet insertion holes 55a to 55d of the magnet holder 55 without using an adhesive, the amount of adhesive applied, the drying time, the cleaning process, and the like are conventionally performed. This eliminates the need for management and improves production efficiency.

  The contact surfaces 55g of the magnet insertion holes 55a to 55d are formed in a taper shape so that the inner peripheral opening is wide and the outer peripheral opening is narrow. Therefore, the magnet insertion holes 55a to 55d are formed in the magnet insertion holes 55a to 55d. The inserted permanent magnet 56 is prevented from falling off due to the centrifugal force when the rotor rotates.

  As shown in FIG. 5, the rotating body 54 includes an insertion portion 54 a inserted into the inner periphery of the magnet holder 55, a flange portion 54 b that contacts the end portion of the magnet holder 55, and the opposite side of the flange portion 54 b. A locking recess 54c into which a protrusion 55i protruding from the inner periphery of the magnet holder 55 is fitted is provided on the outer periphery of the insertion portion 54a. Therefore, when the insertion portion 54 a of the rotating body 54 is inserted into the inner periphery of the magnet holder 55, the flange portion 54 b comes into contact with the end of the magnet holder 55 to restrict the insertion position, and the protrusion 55 i of the magnet holder 55. Is fitted into the locking recess 54c to prevent detachment in the axial direction. Therefore, the rotating body 54, the magnet holder 55, and the permanent magnet 56 are integrated in a state where they cannot be separated from each other.

  Further, in the magnet holder 55, the center O1 of the core 62 of the stator 60 is shifted from the center O2 of the permanent magnet 56 by a predetermined distance Lx toward the flange portion 54b. Thereby, the permanent magnet 56 is always urged | biased by the flange part 54b with the magnetic force of an axial direction (X direction). Therefore, the permanent magnet 56 is held in contact with the flange portion 54b, and movement in the axial direction is restricted by the protrusion 55i of the magnet holder 55 fitting into the locking recess 54c.

  Next, a modified example will be described. FIG. 6 is a cross-sectional view showing a state in which the permanent magnet 56 is attached to the magnet holder 55 of a modified example. As shown in FIG. 6, the magnet holder 55 has an engaging protrusion 55j protruding from the inner periphery of the support portion 55f. The engagement protrusion 55j is formed to extend linearly in the axial direction. Further, an engaging groove 54d into which the engaging protrusion 55j is fitted is formed on the outer periphery of the rotating body 54 so as to extend in the axial direction.

  The engagement protrusions 55j and the engagement grooves 54d are provided at four positions at intervals of 90 degrees in the circumferential direction, and are positioned so as to be fitted to each other when the rotating body 54 is inserted into the inner periphery of the magnet holder 55. To be combined. In a state where the rotary body 54 has been inserted into the inner periphery of the magnet holder 55, the four engagement protrusions 55j and the engagement grooves 54d are engaged, and the magnet holder 55 and the rotary body 54 are integrated. . Therefore, when the rotor 50 is rotated by the driving torque acting on the rotor 50, the magnet holder 55 is prevented from idling around the outer periphery of the rotating body 54 due to the engagement between the engagement protrusion 55j and the engagement groove 54d, and is permanent. Torque acting on the magnet 56 can be reliably transmitted to the rotating body 54.

1 is a longitudinal sectional view showing an inner rotor type brushless motor to which an embodiment of a rotor according to the present invention is applied. It is a figure which shows the magnet holder 55, (A) is a side view, (B) is BB sectional drawing of FIG. 2 (A), (C) is the A section enlarged view of FIG. 2 (B). 3 is a perspective view showing the shape of a permanent magnet 56. FIG. It is a figure which shows the state which attached the permanent magnet 56 to the magnet holder 55, (A) is a side view, (B) is CC sectional drawing of FIG. 4 (A). It is a longitudinal cross-sectional view which follows the DD line | wire in FIG. 4 (B). It is sectional drawing which shows the state which attached the permanent magnet 56 to the magnet holder 55 of the modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inner rotor type brushless motor 20 Bracket 30 Housing 40 Case 50 Rotor 60 Stator 52 Rotating shaft 54 Rotor 54a Insertion part 54b Flange part 55 Magnet holder 55a-55d Magnet insertion hole 55g Contact surface 55h Protrusion 56 Permanent magnet 62 Core 64 Coil

Claims (3)

In a rotor having a cylindrical holding member that holds a permanent magnet disposed inside a stator, and a rotating body that fits on the inner periphery of the holding member,
A plurality of magnet insertion holes penetrating from the inner periphery to the outer periphery in the circumferential direction of the holding member are formed at predetermined intervals,
The rotor, wherein the rotor is fitted to the inner periphery of the holding member in a state where the permanent magnet is inserted into the magnet insertion hole from the inside.   2. The magnet insertion hole according to claim 1, wherein a contact surface that contacts the edge of the permanent magnet is formed in a tapered shape so that the inner peripheral opening is wide and the outer peripheral opening is narrow. Rotor. The rotor according to claim 1, wherein an elastic portion that elastically abuts against an edge portion of the permanent magnet is provided on the abutment surface of the magnet insertion hole.

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