JP2019115121A - Rotor and motor - Google Patents

Abstract

To provide a rotor and a motor capable of easily and reliably fixing a magnet to a rotor core.SOLUTION: The rotor and motor includes: a rotary shaft 31; a rotor core 32 externally fitted and fixed to the rotary shaft 31; a plurality of magnets 33 provided in the rotor core 32; and a magnet holder 34 for fixing the magnet 33 in the rotor core 32. The rotor core 32 has a plurality of magnet storage holes 41 which are formed to be circumferentially long near the outer periphery and in which the magnets 33 are stored. The magnet storage hole 41 is formed to have air gaps 43 at both ends in a circumferential direction in a state where the magnet 33 is stored in the magnet storage hole 41. The magnet holder 34 is made of a compressively deformable elastic body, and has a plurality of magnet fixing portions 46 inserted in a state of being compressed and deformed in each of the air gaps 43; and a holding unit 47 that connects one end of the plurality of magnet fixing units 46.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotor and a motor.

  A so-called brushless motor is provided with a stator in which a coil is wound, and a rotor rotatably supported radially inward of the stator in the motor, and the rotor is rotationally driven by performing energization control of the coil. There is. The rotor has a rotary shaft, a substantially cylindrical rotor core externally fitted and fixed to the rotary shaft, and a magnet provided on the rotor core. Then, a magnetic attraction force and a repulsive force are generated between the linkage flux formed in the stator and the magnet provided in the rotor core, whereby the rotor is continuously rotated.

  Here, as a method of arranging the magnet on the rotor, there is a magnet embedding method (IPM: Interior Permanent Magnet) in which a plurality of magnet housing holes are formed in the rotor core and the magnet is arranged in the magnet housing hole. In this type of rotor, various techniques have been proposed as a method of fixing a magnet to a magnet storage hole of a rotor core.

  For example, Patent Document 1 includes a magnet holder (rotor end plate) for fixing a magnet in a rotor core, and the magnet holder is a first member provided at one axial end of the rotor core (rotor core). And a second member extending from the member. The second member is separated from the outer peripheral portion located on the opposite side to the rotation shaft with respect to the magnet storage hole (storage hole) of the rotor core. The second member holds the magnet together with the inner circumferential portion of the rotor core located on the rotation shaft side with respect to the magnet housing hole.

JP, 2010-226882, A

However, as in Patent Document 1 described above, simply holding the magnet between the second member and the inner peripheral portion of the rotor core can not reliably hold the magnet due to a manufacturing error of the magnet holder, and the magnet There was a possibility of getting out.
Also, as another method of fixing the magnet to the rotor core, a method of fixing the magnet to the rotor core using an adhesive can be considered, but not only the application operation of the adhesive is troublesome, but the application amount of the adhesive must be managed. The problem is that the task of fixing the magnet becomes complicated.

  Then, this invention is made in view of the situation mentioned above, Comprising: The rotor and motor which can fix a magnet to a rotor core easily and reliably are provided.

  In order to solve the above problems, a rotor according to the present invention comprises a rotation shaft, a rotor core fixed to the rotation shaft, a plurality of magnets provided in the rotor core, and the magnets in the rotor core. And a magnet holder for fixing, the rotor core having a plurality of magnet storage holes formed to be long in the circumferential direction toward the outer periphery and storing the magnets, and the magnet storage holes In the state where the magnet is stored in the magnet storage hole, the magnet holder is formed to have a gap at both ends in the circumferential direction, the magnet holder is made of an elastic body that can be compressed and deformed, and a state in which the magnet is compressed and deformed in each of the gaps And a plurality of magnet fixing portions to be inserted at one end of the rotor core in the axial direction, and one end of the plurality of magnet fixing portions being connected And having a lifting unit.

By this configuration, both ends in the circumferential direction of the magnet can be held by the two magnet fixing portions only by inserting the magnet fixing portion into the gap portion. Therefore, the magnet can be easily fixed in the rotor core.
Further, the magnet fixing portion is made of an elastic body that can be compressed and deformed, and is inserted into each of the air gaps in a state of being compressed and deformed. For this reason, the circumferential direction both ends of this magnet can be clamped by two magnet fixing parts, applying pressing force to the circumferential direction both ends of a magnet by the elastic force of a magnet fixing part. Therefore, the magnet can be reliably fixed in the rotor core regardless of the manufacturing error of the rotor core and the magnet.

  The rotor according to the present invention is characterized in that a positioning convex portion for positioning the magnet in the magnet housing hole is provided in a part of the gap portion.

  With this configuration, positioning of the magnet with respect to the rotor core can be performed with high accuracy.

  The rotor according to the present invention is characterized in that a detachment preventing rib for preventing detachment of the magnet from the magnet storage hole is provided at the other axial direction end of the rotor core opposite to the holding part. I assume.

With such a configuration, the magnet can be reliably prevented from coming off the rotor core by the holding portion disposed at one axial end of the rotor core and the detachment preventing rib provided at the other axial end of the rotor core.
Furthermore, by providing the detachment preventing rib, it is not necessary to provide a holding portion at the other axial end of the rotor core, and the structure of the magnet holder can be simplified and the cost can be reduced.

  In the rotor according to the present invention, the magnet fixing portion and the holding portion are integrally formed, the magnet fixing portion is formed of an elastomeric resin, and the holding portion is higher than the hardness of the magnet fixing portion. It is characterized in that it is made of a resin of hardness.

  By configuring in this manner, the number of parts of the entire rotor can be reduced. Further, by changing the hardness as necessary, the magnet fixing portion can be configured to have elasticity, while the holding portion can be configured to be able to reliably connect the magnet fixing portions.

  In the rotor according to the present invention, at least one of the magnet fixing portion and the air gap portion is provided with a relief portion that allows elastic deformation of the magnet fixing portion inserted into the insertion portion. I assume.

  With this configuration, it is possible to prevent the magnet from being damaged because the pressing force applied to the magnet by the magnet fixing portion becomes larger than necessary. In addition, it is possible to prevent the magnet fixing portion and the rotor core from being damaged by applying stress to the magnet fixing portion and the rotor core more than necessary.

  In the rotor according to the present invention, the holding portion has a positioning portion for positioning the rotor core with respect to the magnetizing device.

  With this configuration, after the base material of the magnet is stored in the magnet storage hole of the rotor core, desired magnetization of the magnet can be reliably performed by the magnetizing device.

  A motor according to the present invention includes the above-described rotor, and a stator formed so as to surround the periphery of the rotor and having a coil wound thereon.

  With this configuration, it is possible to provide a motor that can easily and reliably fix the magnet to the rotor core.

  A motor according to the present invention comprises a rotational position detection device for detecting the rotational position of the rotor, and the holding portion has a sensor arrangement portion for mounting the rotational position detection device.

  With this configuration, it is possible to increase the accuracy of the mounting position of the rotational position detection device with respect to the rotor core. Therefore, a high quality motor can be provided.

According to the present invention, the circumferential direction both ends of the magnet can be held by the two magnet fixing portions only by inserting the magnet fixing portion into the gap portion. Therefore, the magnet can be easily fixed in the rotor core.
Further, the magnet fixing portion is made of an elastic body that can be compressed and deformed, and is inserted into each of the air gaps in a state of being compressed and deformed. For this reason, the circumferential direction both ends of this magnet can be clamped by two magnet fixing parts, applying pressing force to the circumferential direction both ends of a magnet by the elastic force of a magnet fixing part. Therefore, the magnet can be reliably fixed to the rotor core regardless of the manufacturing error of the rotor core or the magnet.

It is a sectional view of a brushless motor in an embodiment of the present invention. It is a side view of a rotor in an embodiment of the present invention. It is an exploded perspective view of a rotor in an embodiment of the present invention. It is a perspective view of a rotor core in an embodiment of the present invention. It is a perspective view of the magnet holder in the embodiment of the present invention. It is sectional drawing in alignment with the AA of FIG. It is the B section enlarged view of FIG. It is sectional drawing which follows the CC line of FIG.

  Next, an embodiment of the present invention will be described based on the drawings.

(Brushless motor)
FIG. 1 is a cross-sectional view of the brushless motor 1.
The brushless motor 1 is used, for example, in electric power steering (EPS).
As shown in FIG. 1, the brushless motor 1 is housed in a substantially bottomed cylindrical motor case 2, a substantially disk-shaped bracket 3 closing the opening 2 a of the motor case 2, and the motor case 2. And a rotor 5 rotatably provided relative to the stator 4. In the following description, the rotational axis direction of the rotor 5 is simply referred to as the axial direction, the rotational direction of the rotor 5 as the circumferential direction, and the radial direction of the rotor 5 orthogonal to the axial direction and the circumferential direction as the radial direction.

(Motor case)
At the opening 2 a of the motor case 2, an outer flange portion 15 protruding outward in the radial direction is formed to be bent. At the outer peripheral portion of the outer flange portion 15, a plurality of (three in the present embodiment) bolt seats 16 are extended radially outward. The bolt seat 16 is for fixing the brushless motor 1 to an external device (not shown). The bolt seats 16 are arranged at substantially equal intervals in the circumferential direction. Each bolt seat 16 is formed with a bolt insertion hole 16a through which a bolt (not shown) can be inserted.

  The stator 4 is fitted and fixed to the peripheral wall 2 b of the motor case 2. Further, the motor case 2 is provided with a bearing housing 6 formed in a substantially cylindrical shape by bending the bottom portion 2 c substantially at the center in the radial direction of the bottom portion 2 c. The bearing housing 6 is provided with a bearing 23 on which one end of the rotation shaft 31 of the rotor 5 is rotatably supported.

(Stator)
The stator 4 has a substantially cylindrical stator core 7. The stator core 7 is formed by laminating in the axial direction a metal plate (magnetic steel plate) punched into a substantially annular shape by press working, or press forming soft magnetic powder. In the stator core 7, a plurality of teeth 8 protruding inward in the radial direction are formed in line in the circumferential direction. Further, an insulator 9 which is an insulating material is attached to the stator core 7 so as to cover the periphery of the teeth 8. A coil 10 is wound around each of the teeth 8 from above the insulator 9.

  On the opposite side to the bottom 2 c of the motor case 2 in the stator 4, a bus bar unit 11 having a substantially annular shape as viewed in the axial direction is provided. The bus bar unit 11 connects the coils 10 and electrically connects the coils 10 to an external power supply (not shown). The bus bar unit 11 includes a plurality of bus bars 12 that connect the coils 10 to each assigned phase, and a resin mold portion 13 that integrates the plurality of bus bars 12 in a state of being insulated from each other. The terminal portion of each coil 10 is drawn toward the bus bar unit 11 and connected to the corresponding bus bar 12.

(bracket)
The bracket 3 is disposed such that the rear surface 3 a of the bracket 3 on the motor case 2 side is superimposed on the outer flange portion 15 of the motor case 2. At the outer peripheral portion of the bracket 3, bolt seats 19 are extended radially outward so as to overlap with the bolt seats 16 of the motor case 2. The bolt seat 19 also has a bolt insertion hole 19a through which a bolt (not shown) can be inserted. When the brushless motor 1 is fixed to an external device (not shown), the bolt seat 19 of the bracket 3 and the bolt seat 16 of the motor case 2 are fastened together by bolts (not shown).

  On the back surface 3 a of the bracket 3, a cylindrical inlay portion 14 fitted to the peripheral wall 2 b of the motor case 2 is formed to protrude. Positioning of the bracket 3 relative to the motor case 2 in the radial direction is performed by the inlay portion 14.

Further, on the surface 3b opposite to the motor case 2 of the bracket 3, a substantially bottomed cylindrical bearing housing 17 which protrudes outward in the axial direction by bending the bracket 3 substantially at the center in the radial direction It is formed. The bearing housing 17 is provided with a bearing 24 on which the other end side of the rotation shaft 31 of the rotor 5 is rotatably supported.
Further, in the upper wall 17 a of the bearing housing 17, a rotation shaft insertion hole 17 b through which the other end side of the rotation shaft 31 can be inserted is formed. The other end of the rotary shaft 31 protrudes outward in the axial direction via the rotary shaft insertion hole 17b.

  Further, on the surface 3 b of the bracket 3, a terminal 20 to which a connector (not shown) extending from an external power supply (not shown) is connected is provided. The terminal 20 is one in which a terminal 22 is provided in a terminal holder 21 made of resin. One end of the terminal 22 protrudes from the terminal holder 21 to the outside. On the other hand, the other end of the terminal 22 penetrates the bracket 3 and protrudes toward the bus bar unit 11 side. Then, the bus bar 12 of the bus bar unit 11 and the other end of the terminal 22 are connected. Thus, power is supplied to each coil 10 through the terminal 20 and the bus bar unit 11.

A substantially disk-shaped holder bracket 18 is provided on the back surface 3 a of the bracket 3 so as to close the opening 17 c opposite to the upper wall 17 a of the bearing housing 17.
At a position corresponding to the bearing housing 17 of the holder bracket 18, a rotation shaft insertion hole 18a through which the rotation shaft 31 can be inserted is formed. Further, a substantially cylindrical resolver holder 25 is provided on one surface 18 b of the holder bracket 18 on the side of the bus bar unit 11 so as to surround the rotation shaft insertion hole 18 a. The end of the resolver holder 25 opposite to the holder bracket 18 faces the inside of the bus bar unit 11 in the radial direction. On the other hand, at the end surface of the resolver holder 25 on the side of the holder bracket 18, an outer flange portion 29 projecting outward in the radial direction is bent and extended. The outer flange portion 29 is fixed to the holder bracket 18.

  A resolver stator 27 constituting one of the resolvers 26 is fixedly fitted to the resolver holder 25. The resolver 26 is a device that detects the rotational position of the rotor 5. The resolver stator 27 detects the rotational position of a resolver rotor 28 described later provided on the rotor 5.

(Rotor)
FIG. 2 is a side view of the rotor 5. FIG. 3 is an exploded perspective view of the rotor 5.
As shown in FIGS. 1 to 3, the rotor 5 has a rotary shaft 31 rotatably supported by the motor case 2 and the bracket 3, a rotor core 32 externally fitted and fixed to the rotary shaft 31, and the rotor core 32. And a magnet holder 34 for fixing the magnet 33 in the rotor core 32.

  The rotating shaft 31 is formed in a stepped shape where the diameter corresponding to the stator 4 is expanded most. That is, the rotation shaft 31 has a rotor core fixing portion 35 disposed at a position corresponding to the stator 4 and a first diameter reduction formed on one end side (lower side in FIG. 1) of the rotor core fixing portion 35 via the step 36 a. A bearing portion 36, a holder fixing portion 37 whose diameter is reduced on the other end side (upper side in FIG. 1) of the rotor core fixing portion 35 via the step 37a, and a step 38a on the other end side of the holder fixing portion 37 It is comprised by the 2nd bearing part 38 by which diameter reduction was formed.

The first bearing portion 36 is rotatably supported by a bearing 23 provided on the motor case 2. The second bearing portion 38 is rotatably supported by a bearing 24 provided on the bracket 3. Further, the second bearing portion 38 protrudes outward in the axial direction via the bearing 24. A joint 39 is externally fitted and fixed to this protruding point. The joint 39 is connected to an external device, such as a reduction gear, and has a role of transmitting the rotational force of the brushless motor 1 to the external device.
The rotor core 32 is externally fixed to the rotor core fixing portion 35.

(Rotor core)
FIG. 4 is a perspective view of the rotor core 32. As shown in FIG.
As shown in FIGS. 2 to 4, the rotor core 32 is formed in a substantially cylindrical shape. The rotor core 32 is formed by laminating in the axial direction a metal plate (magnetic steel plate) punched into a substantially circular shape by press processing, or press-molding soft magnetic powder.
At the radial center of the rotor core 32, a rotary shaft press-in hole 40 into which the rotor core fixing portion 35 of the rotary shaft 31 is press-fitted is formed. On the inner circumferential surface of the rotary shaft press-in hole 40, a plurality of (six in the present embodiment) relief recesses 40a formed over the entire axial direction are arranged at equal intervals in the circumferential direction. The relief recess 40 a is for relieving stress applied to the rotor core 32 when the rotary shaft 31 is press-fit into the rotor core 32. The relief recess 40 a is formed to be curved as viewed in the axial direction.

  A plurality of (six in the present embodiment) magnet housing holes 41 are formed in the outer peripheral portion of the rotor core 32 so as to penetrate the rotor core 32 in the axial direction. The magnet storage hole 41 is for storing the magnet 33 in the rotor core 32. The magnet housing hole 41 is constituted by a rectangular housing hole main body 42 which is long in the circumferential direction as viewed from the axial direction, and a gap 43 which is formed at both circumferential ends of the housing hole main body 42 and communicates with the housing hole main body 42. ing.

  The magnet 33 is housed in the housing hole main body 42. The housing hole main body 42 has a flat first inner side surface 42a positioned radially inward and a flat second inner side surface 42b positioned radially outward so as to radially face the inner side surface 42a. doing.

  A magnet fixing portion 46 described later of the magnet holder 34 is inserted into the air gap 43. The inner side surface of the cavity 43 is bent from the first inner side surface 42a of the storage hole main body 42 radially inward so as to be orthogonal to the first inner side surface 42a, and the first inner side surface 43a And a second inner side surface 43b parallel to the first inner side surface 42a of the accommodation hole main body 42 and extending circumferentially outward, and a first inner surface 43b extending radially outward from the second inner side surface 43b And a fourth inner side surface 43d extending obliquely from the third inner side surface 43c along the outer peripheral surface of the rotor core 32 and connected to the second inner side surface 42b of the storage hole main body 42. .

  In the gap 43, a magnet is disposed on the side of the first bearing portion 36 of the rotary shaft 31 (hereinafter, the side of the first bearing portion 36 (lower side in FIG. 1) is simply referred to as the first bearing portion 36 side). Positioning convex parts 44 are formed to protrude. The magnet positioning convex portion 44 is for positioning the magnet 33 housed in the housing hole main body 42 in the circumferential direction. The magnet positioning convex portion 44 is perpendicular to the first side surface 44a extending from the first inner side surface 42a of the housing hole main body 42 along the first inner side surface 42a and the first side surface 44a from the first side surface 44a. And the second side surface 44b bent and extended radially outward, and extends from the second side surface 44b in a direction parallel to the first inner side surface 42a of the storage hole main body 42 and circumferentially outward. And a third side surface 44c connected to the inner side surface 43c.

  Further, the outer peripheral surface of the rotor core 32 is constituted by the curved outer peripheral surface 32 a as many as the number of the magnet housing holes 41. Each curved outer peripheral surface 32 a is curved and formed so as to protrude radially outward as it goes to the circumferential center when viewed from the axial direction. Therefore, the circumferentially central position of the curved outer peripheral surface 32 a that protrudes most radially outward and the circumferentially central position of the magnet housing hole 41 coincide with each other. And both circumferential direction both ends of each curved outer peripheral surface 32a are connected, and the whole outer peripheral surface of the rotor core 32 is formed.

  Further, the rotor core 32 is provided at the end portion of the rotary shaft 31 on the first bearing portion 36 side with a detachment preventing rib 45 straddling the center in the circumferential direction of the magnet accommodation hole 41. The detachment preventing rib 45 is for restricting the detachment of the magnet 33 accommodated in the magnet accommodation hole 41 to one side (the lower side in FIG. 1).

Thus, in the rotor core 32, the first layer S1 on which the detachment preventing rib 45 and the magnet positioning convex portion 44 are formed, the second layer S2 on which only the magnet positioning convex portion 44 is formed, and the detachment preventing rib 45 And the third layer S3 in which the magnet positioning convex portion 44 is not formed (see FIG. 2).
For example, when the rotor core 32 is formed by laminating metal plates (electromagnetic steel plates) in the axial direction, the metal plate constituting the first layer S1, the metal plate constituting the second layer S2, and the third layer It is possible to form with three types of metal plates of, and the metal plate which constitutes.

  As shown in FIG. 3, the magnet 33 housed in the magnet housing hole 41 is formed in a plate shape having a rectangular cross section so as to correspond to the shape of the housing hole main body 42. That is, as shown in FIG. 3 and FIG. 4, the magnet 33 is formed such that the plate thickness H1 is approximately the same as or slightly smaller than the radial width H2 of the storage hole main body 42. The magnet 33 is formed such that the circumferential width W1 is approximately the same as or slightly smaller than the width W2 between the first side surfaces 44a of the magnet positioning convex portion 44 formed in the magnet housing hole 41. ing. Therefore, circumferential positioning of the magnet 33 with respect to the magnet housing hole 41 is performed by the magnet positioning convex portion 44.

(Magnet holder)
FIG. 5 is a perspective view of the magnet holder 34.
As shown in FIGS. 3 and 5, the magnet holder 34 includes a plurality of (12 in the present embodiment) magnet fixing portions 46 inserted into the air gaps 43 of the rotor core 32, and bus bar units in the magnet fixing portions 46. And a holding portion 47 for connecting the end portion (proximal end portion) on the 11 side. Moreover, the magnet holder 34 forms the magnet fixing | fixed part 46 and the holding | maintenance part 47 by 2 color molding with resin.

The magnet fixing portion 46 is formed of an elastomeric resin having elasticity that allows compression and deformation. The magnet fixing portion 46 is formed in a rod shape so as to be inserted over the entire axial direction of the air gap 43 and to correspond to the shape of the air gap 43.
More specifically, the magnet fixing portion 46 is extended from the fixing portion main body 48 inserted into the gap 43 at a position corresponding to the third layer S 1 of the rotor core 32 and the tip of the fixing portion main body 48. And a tip 49 inserted into the gap 43 at a position corresponding to the second layer S2 and the first layer.

6 is a cross-sectional view taken along the line A-A of FIG. FIG. 7 is an enlarged view of a portion B of FIG.
As shown in FIGS. 5 to 7, the fixing portion main body 48 of the magnet fixing portion 46 is formed in a substantially columnar shape. The fixing portion main body 48 is in contact with the magnet contact side surface 48 a that contacts the circumferential side surface 33 a of the magnet 33 housed in the housing hole main body 42 of the magnet housing hole 41 and the first inner side surface 43 a of the gap 43. The first side 48b, the second side 48c in contact with the second inner side 43b of the cavity 43, the third side 48d in contact with the third inner side 43c of the cavity 43, and the fourth inner side 43d of the cavity 43 The magnet contact side surface 48a and the first side surface 48b are connected to each other, and a corner portion contact side surface 48f is in contact with the corner portion of the magnet 33.

  Here, the fixing portion main body 48 of the magnet fixing portion 46 is formed in such a size as to be in a state of being slightly compressed when the fixing portion main body 48 is inserted into the gap 43. In order to allow the compressive deformation of the fixing portion main body 48, the fixing portion main body 48 includes three relief portions 51, 52, 53 (a first relief portion 51, a second relief portion 52, a third relief portion 53). It is formed. The three relief portions 51, 52, 53 will be described in detail below.

  As shown in detail in FIG. 7, in the fixing portion main body 48, contact between the fixing portion main body 48 and the inner side surfaces 43 b and 43 c of the air gap portion 43 is made at the connection portion between the second side surface 48 c A first escape portion 51 for avoiding is formed. The first relief portion 51 is in the form of a groove formed to cut off a portion of the second side surface 48c and a portion of the third side surface 48d, and is formed over the entire axial direction of the fixing portion main body 48 There is.

  Further, in the fixing portion main body 48, a second relief for avoiding the contact between the fixing portion main body 48 and the inner side surfaces 43c and 43d of the gap portion 43 in the connection portion between the third side surface 48d and the fourth side surface 48e. The part 52 is formed. The second relief portion 52 is a flat surface formed to cut off a portion of the third side surface 43d and a portion of the fourth side surface 48e, and is formed over the entire axial direction of the fixing portion main body 48 There is.

  Furthermore, in the fixing portion main body 48, a third relief for avoiding contact between the fixing portion main body 48 and the fourth inner side surface 43d of the air gap portion 43 in the connection portion between the fourth side surface 48e and the magnet abutting side surface 48a. The part 53 is formed. The third relief portion 53 is a flat surface formed to cut off a portion of the fourth side surface 48 e and a portion of the magnet contact side surface 48 a, and is formed over the entire axial direction of the fixed portion main body 48. ing.

FIG. 8 is a cross-sectional view taken along the line C-C of FIG.
As shown in FIGS. 3, 5 and 8, the tip 49 of the magnet fixing portion 46 is a portion of the air gap 43 of the magnet housing hole 41 where the magnet positioning convex portion 44 is formed, that is, the air gap The cross-sectional shape orthogonal to the axial direction is formed to be substantially triangular so that it can be inserted into the portion corresponding to the 43 second layer S2.

  That is, the front end portion 49 contacts the magnet contact side surface 49 a that contacts the circumferential side surface 33 a of the magnet 33 housed in the housing hole main body 42 of the magnet housing hole 41 and the third side surface 44 c of the magnet positioning convex portion 44. It has positioning convex part contact side 49b to be in contact and gap contact side 49c to be in contact with the third inner side 43c of the gap 43. Further, an inclined surface 49d is formed on the gap contact side surface 49c of the distal end portion 49 so that the distal end portion 49 has a tapered shape.

  The holding portion 47 is formed of a resin having a hardness higher than the hardness of the magnet fixing portion 46. For example, the holding portion 47 is formed of a resin (for example, PBT or the like) having high affinity to the magnet fixing portion 46. The holding portion 47 is disposed at an end of the rotor core 32 opposite to the bottom portion 2 c of the motor case 2 and has a substantially disk-shaped holding portion main body 58 connecting the end portions of the respective magnet fixing portions 46. The diameter of the holding portion main body 58 is set to be substantially the same as the outermost diameter of the rotor core 32.

A plurality of (six in the present embodiment) positioning holes 56 are formed in the holding portion main body 58 radially inward of the portion where the magnet fixing portion 46 is connected. The positioning hole 56 is formed in a substantially arc shape as viewed in the axial direction so as to be long along the circumferential direction. The positioning holes 56 are arranged at equal intervals in the circumferential direction.
The positioning holes 56 are used when positioning the magnetizing device and the rotor core 32 when magnetizing the base material of the magnet 33 after assembling the base material of the magnet 33 to the rotor core 32 (details Will be described later). Further, the positioning holes 56 have a role of reducing the weight of the magnet holder 34 and a role of enhancing the cooling effect of the rotor core 32.

  The base material of the magnet 33 refers to a material which is not magnetized yet in a state where the shape of the magnet 33 is formed of neodymium or ferrite. In the present embodiment, although the magnet 33 and the base material of the magnet 33 are used selectively for convenience of explanation, the function and effect are different between the case where the magnet 33 is magnetized and the state of the base material not magnetized. There is no. For this reason, in the operation and effect of this embodiment, the magnet 33 and the base material of the magnet 33 are handled as the same.

  At the radial center of the holding portion main body 58, a substantially cylindrical rotating shaft outer fitting portion 54 is formed so as to project toward the side opposite to the rotor core 32. The inner peripheral surface 54 a of the rotary shaft outer fitting portion 54 is fitted to the other end side of the rotor core fixing portion 35 of the rotary shaft 31 and the entire holder fixing portion 37. An enlarged diameter portion 55 is formed on the inner peripheral surface 54 a of the rotation shaft outer fitting portion 54 on the side of the connecting portion with the holding portion main body 58 with the diameter enlarged through the step 55 a. The enlarged diameter portion 55 is fitted to the other end of the rotor core fixing portion 35 of the rotating shaft 31.

Further, a plurality of (three in the present embodiment) resolver rotor holding claws 57 are formed to project along the axial direction at the tip of the rotation shaft outer fitting portion 54 on the opposite side to the holding portion main body 58. The resolver rotor 28 constituting the other of the resolver 26 is attached to the resolver rotor holding claw 57.
The resolver rotor 28 is formed in a substantially annular shape through which the rotation shaft can be inserted. On the inner peripheral surface of the resolver rotor 28, an engagement recess 28a is formed at a position corresponding to the resolver rotor holding claw 57, into which the resolver rotor holding claw 57 is inserted. The resolver rotor 28 and the magnet holder 34 are engaged with each other by inserting the resolver rotor holding claw 57 into the engagement recess 28 a. Thereby, the resolver rotor 28 and the magnet holder 34 are integrated so as not to be relatively rotatable.

  Further, the resolver rotor 28 is located radially inward of the resolver stator 27 that constitutes one of the resolvers 26. Then, the resolver rotor 28 rotates integrally with the rotor 5 via the magnet holder 34. Thereby, the resolver stator 27 can detect the rotational position of the resolver rotor 28. As a result, the rotational position of the rotor 5 can be detected by the resolver 26.

(Assembling of magnet to rotor core)
Next, an operation of assembling the magnet 33 to the rotor core 32 will be described. The rotor core 32 may be assembled to the rotation shaft 31 after the magnet 33 is assembled to the rotor core 32 or before the magnet 33 is assembled to the rotor core 32. In the following description, for convenience of explanation, the first bearing portion 36 side of the rotary shaft 31 in the rotor core 32 is simply referred to as the first bearing portion 36 side, and the holder fixing portion 37 side of the rotary shaft 31 in the rotor core 32 (The upper side in FIG. 1) will be simply referred to as the holder fixing portion 37 side.

First, the base material of the magnet 33 is inserted into the magnet housing hole 41 of the rotor core 32 from the holder fixing portion 37 side. At this time, the circumferential end of the base material of the magnet 33 abuts on the first side surface 44 a of the magnet positioning convex portion 44 formed in the magnet housing hole 41, whereby the magnet 33 for the rotor core 32 (magnet housing hole 41) Positioning of the base material in the circumferential direction is performed.
In addition, a detachment preventing rib 45 is provided at an end of the rotor core 32 on the first bearing portion 36 side. For this reason, the base material of the magnet 33 inserted from the holder fixing portion 37 side of the magnet housing hole 41 is prevented from dropping off from the first bearing portion 36 side. Further, positioning of the magnet 33 in the axial direction with respect to the rotor core 32 (the magnet housing hole 41) is performed.

Subsequently, the tip end 49 of the magnet holder 34 is directed to the gap 43 of the magnet housing hole 41. Then, the magnet fixing portion 46 of the magnet holder 34 is inserted into the gap portion 43 from the holder fixing portion 37 side. At this time, the tip end portion 49 is tapered since the inclined surface 49 d is formed, so that the holder fixing portion 37 can be easily inserted into the magnet housing hole 41.
Subsequently, the magnet fixing portion 46 is inserted into the gap 43 until the holding portion main body 58 of the magnet holder 34 abuts on the end surface of the rotor core 32 on the holder fixing portion 37 side. Then, the tip 49 is inserted into the gap 43 at a position corresponding to the second layer S2 and the first layer of the rotor core 32. Further, the fixing portion main body 48 is inserted into the air gap portion 43 of a portion corresponding to the third layer S1 of the rotor core 32.

  Here, the fixing portion main body 48 is formed in such a size as to be slightly compressed when the fixing portion main body 48 is inserted into the gap portion 43. For this reason, as shown in FIG. 7, the compressive deformation causes a force F1 to press the base material of the magnet 33 from both sides in the circumferential direction on the fixed portion main body 48. In addition, a force F2 that pushes the base material of the magnet 33 radially outward acts on the fixing portion main body 48.

  Therefore, the frictional resistance of the fixing portion main body 48 to the base material of the magnet 33 is increased, and the base material of the magnet 33 is reliably fixed to the magnet housing hole 41 of the rotor core 32. Further, the base material of the magnet 33 is pressed against the second inner side surface 42b of the housing hole main body 42 by the force F2 that presses the base material of the magnet 33 radially outward. For this reason, the positioning of the base material of the magnet 33 in the radial direction is accurately performed.

Further, in the fixing portion main body 48, three relief portions 51, 52, 53 (a first relief portion 51, a second relief portion 52, a third relief portion 53) are formed. For this reason, when the fixing portion main body 48 is compressed and deformed, the thickness of the fixing portion main body 48 escapes to each of the relief portions 51, 52, 53 and extra stress is applied to the fixing portion main body 48, the rotor core 32, and the magnet 33. Is suppressed.
Then, the magnet 33 is fixed to the rotor core 32 by the magnet holder 34, whereby the work of assembling the magnet 33 to the rotor core 32 is completed.

  After the work of assembling the magnet 33 to the rotor core 32 is completed, the base material of the magnet 33 is magnetized. Specifically, the rotor core 32 to which the base material of the magnet 33 is fixed is set in a magnetizing device (not shown), and a predetermined voltage is applied to the rotor core 32.

  Here, positioning holes 56 are formed in the holding portion main body 58 of the magnet holder 34. On the other hand, the magnetizing device (not shown) is provided with a positioning convex portion (not shown) which can be fitted into the positioning hole 56. Therefore, by setting the rotor core 32 in the magnetizing device so that the positioning hole 56 is fitted to the positioning convex portion, it is possible to accurately position the rotor core 32 with respect to the magnetizing device. Therefore, the base material of the magnet 33 can be magnetized with high precision.

  In addition, since the magnet 33 is disposed on the second inner side surface 42b of the storage hole main body 42 so that the base material of the magnet 33 is pressed, the magnet 33 magnetized with the storage hole main body 42 and the second inner side surface 42b There is no need to form an extra gap between them. Therefore, the magnetic flux of the magnet 33 is efficiently transmitted to the outer peripheral portion of the rotor core 32, and the effective magnetic flux of the rotor core 32 can be increased as much as possible.

  Thereafter, the resolver rotor 28 is assembled to the resolver rotor holding claws 57 of the magnet holder 34, and the assembling operation of the rotor 5 is completed.

(Operation of brushless motor)
Next, the operation of the brushless motor 1 will be described.
When power from an external power supply (not shown) is selectively supplied to each coil 10 via the terminal 20 and the bus bar unit 11, a predetermined magnetic field is generated in the stator 4. Then, a magnetic attractive force or repulsive force is generated between this magnetic field and the magnet 33 provided on the rotor 5. Thereby, the rotor 5 rotates.

When the rotor 5 rotates, the resolver rotor 28 attached to the magnet holder 34 also integrally rotates. The rotational position of the resolver rotor 28 is detected by the resolver stator 27. Thereby, the rotational position of the rotor 5 is detected by the resolver 26.
An external power supply (not shown) selectively supplies power to each coil 10 based on the detection result of the resolver 26. For this reason, the rotor 5 rotates continuously.

  Here, the outer peripheral surface of the rotor core 32 is constituted by the curved outer peripheral surface 32 a as many as the number of the magnet housing holes 41. Each curved outer peripheral surface 32 a is curved and formed so as to protrude radially outward as it goes to the circumferential center when viewed from the axial direction. Therefore, the distance between the inner peripheral surface of the stator 4 and the outer peripheral surface of the rotor core 32 becomes larger as it goes to both ends in the circumferential direction of the curved outer peripheral surface 32a. That is, the distance between the inner circumferential surface of the stator 4 and the outer circumferential surface of the rotor core 32 becomes larger as the magnetic pole boundary of the rotor core 32 is approached. As this interval increases, it is possible to suppress the rapid change of the magnetic pole to the stator 4 by the rotor 5. Therefore, the cogging torque of the brushless motor 1 can be suppressed.

As described above, in the above embodiment, in order to fix the magnet 33 in the magnet housing hole 41 of the rotor core 32, the magnet housing hole 41, the housing hole main body 42 for housing the magnet 33, and the circumference of the housing hole main body 42 The gap 43 is formed at both ends in the direction and communicates with the storage hole main body 42. Further, a magnet holder having a magnet fixing portion 46 inserted into each of the air gap portions 43 for fixing the magnet 33 in the magnet housing hole 41, and a holding portion 47 connecting the base end portion of each magnet fixing portion 46 34 was provided.
For this reason, the circumferential direction both ends of the magnet 33 can be held by the two magnet fixing portions 46 only by inserting the magnet fixing portion 46 into the gap 43. Therefore, the magnet 33 can be easily fixed in the rotor core 32.

  Further, the magnet fixing portion 46 is formed of an elastomeric resin having elasticity that allows compression and deformation. Then, the magnet fixing portion 46 is inserted (press-fitted) into the air gap 43 in a state of being compressed and deformed. For this reason, while applying a pressing force to the circumferential direction both ends of the magnet 33 by the elastic force of the magnet fixing portion 46, the circumferential direction both ends of the magnet 33 can be held by the two magnet fixing portions. Therefore, regardless of the manufacturing error of the rotor core 32 or the magnet 33, the magnet 33 can be reliably fixed in the rotor core 32.

  Further, a magnet positioning convex portion 44 is formed to project from the air gap portion 43 on the side of the first bearing portion 36 of the rotating shaft 31. Therefore, the circumferential positioning of the magnet 33 with respect to the rotor core 32 (the magnet housing hole 41) can be performed with high accuracy.

  Moreover, due to the compressive deformation of the magnet fixing portion 46, a force F1 that presses the base material of the magnet 33 from both sides in the circumferential direction acts on the fixing portion main body 48. In addition, a force F2 that pushes the base material of the magnet 33 radially outward acts on the fixing portion main body 48. Therefore, the circumferential positioning of the magnet 33 with respect to the rotor core 32 (the magnet housing hole 41) can be performed with higher accuracy. In addition, since the magnet 33 is disposed on the second inner side surface 42b of the storage hole main body 42 so that the base material of the magnet 33 is pressed, the magnet 33 magnetized with the storage hole main body 42 and the second inner side surface 42b There is no need to form an extra gap between them. Therefore, the magnetic flux of the magnet 33 is efficiently transmitted to the outer peripheral portion of the rotor core 32, and the effective magnetic flux of the rotor core 32 can be increased as much as possible.

  Further, the rotor core 32 is provided at the end portion of the rotary shaft 31 on the first bearing portion 36 side with a detachment preventing rib 45 straddling the center in the circumferential direction of the magnet accommodation hole 41. For this reason, the base material of the magnet 33 inserted from the holder fixing portion 37 side of the magnet housing hole 41 is prevented from dropping off from the first bearing portion 36 side. As a result, assembly of the base material of the magnet 33 to the magnet storage hole 41 is facilitated. Further, by providing the detachment preventing rib 45, it is not necessary to separately provide the holding portion 47 and the like at the first bearing portion 36 side end of the rotor core 32. Therefore, the structure simplification and cost reduction of the magnet holder 34 can be achieved.

  Moreover, the magnet holder 34 forms the magnet fixing | fixed part 46 and the holding | maintenance part 47 by 2 color molding with resin. The magnet fixing portion 46 is formed of an elastic elastomer, while the holding portion 47 is formed of a resin having a hardness higher than the hardness of the magnet fixing portion 46. For this reason, the number of parts of the whole rotor 5 can be reduced. Further, the plurality of magnet fixing portions 46 can be reliably connected by the holding portion 47.

  Further, in the fixing portion main body 48, three relief portions 51, 52, 53 (a first relief portion 51, a second relief portion 52, a third relief portion 53) are formed. Therefore, when the fixing portion main body 48 is compressed and deformed, the meat of the fixing portion main body 48 can be released to each of the relief portions 51, 52, 53. Therefore, unnecessary stress can be suppressed from being applied to the fixing portion main body 48, the rotor core 32, and the magnet 33, and damage to the fixing portion main body 48, the rotor core 32, and the magnet 33 can be suppressed.

  Further, positioning holes 56 are formed in the holding portion main body 58 in the magnet holder 34. Therefore, by using the positioning holes 56, the positioning of the rotor core 32 with respect to the magnetizing device (not shown) can be performed with high accuracy. Therefore, the base material of the magnet 33 can be magnetized with high accuracy.

  Further, a plurality of (three in the present embodiment) resolver rotor holding claws 57 are formed in a projecting manner in the rotation shaft outer fitting portion 54 of the magnet holder 34. Then, the resolver rotor holding claws 57 are attached to the resolver rotor 28 that constitutes the other of the resolver 26. Thus, the rotor core 32 and the resolver rotor 28 are integrated via the magnet holder 34. For this reason, the accuracy of the attachment position of the resolver rotor 28 with respect to the rotor core 32 can be raised. Therefore, the rotational position detection accuracy of the rotor 5 by the resolver 26 can be enhanced, and the high quality brushless motor 1 can be provided.

  Further, the outer peripheral surface of the rotor core 32 is constituted by the curved outer peripheral surface 32 a as many as the number of the magnet housing holes 41. Each curved outer peripheral surface 32 a is curved and formed so as to protrude radially outward as it goes to the circumferential center when viewed from the axial direction. Therefore, the distance between the inner circumferential surface of the stator 4 and the outer circumferential surface of the rotor core 32 becomes larger as the magnetic pole boundary of the rotor core 32 is approached. As this interval increases, it is possible to suppress the rapid change of the magnetic pole to the stator 4 by the rotor 5. Therefore, the cogging torque of the brushless motor 1 can be suppressed.

  Further, at the radial center of the rotor core 32, a rotary shaft press-fit hole 40 into which the rotor core fixing portion 35 of the rotary shaft 31 is press-fitted is formed. On the inner circumferential surface of the rotary shaft press-in hole 40, a plurality of (six in the present embodiment) relief recesses 40a formed over the entire axial direction are arranged at equal intervals in the circumferential direction. The stress applied to the rotor core 32 can be relieved when the rotary shaft 31 is pressed into the rotor core 32 by the relief recess 40 a.

The present invention is not limited to the above-described embodiment, and includes the above-described embodiment with various modifications, without departing from the spirit of the present invention.
For example, the case where the brushless motor 1 is used for electric power steering (EPS) has been described. However, the present invention is not limited to this, and the brushless motor 1 can be adopted for various electric devices.

  In the above embodiment, three reliefs 51, 52, 53 (first relief 51, second relief 52, third relief 53) are formed in the magnet fixing portion 46 of the magnet holder 34. Explained. The clearances 51, 52, 53 prevent the fixing portion main body 48, the rotor core 32, and the magnet 33 from being subjected to an unnecessary stress when the fixing portion main body 48 of the magnet fixing portion 46 is compressed and deformed. The case was described. However, the present invention is not limited to this, and a relief may be formed on the inner peripheral surface of the air gap 43, and the relief main body 48, the rotor core 32, and the magnet 33 may be unnecessarily stressed by this relief. You may comprise so that it can suppress.

  Moreover, in the above-mentioned embodiment, the case where the magnet positioning convex part 44 for positioning the magnet 33 was protruded and formed in the 1st bearing 36 side end of the space | gap part 43 was demonstrated. However, the formation position of the magnet positioning convex portion 44 is not limited to the end on the first bearing portion 36 side of the air gap 43, and may be formed at any position in the axial direction of the air gap 43. That is, the magnet positioning convex portion 44 may be disposed such that the position of the magnet 33 with respect to the magnet housing hole 41 is determined by the magnet positioning convex portion 44.

  Moreover, in the above-mentioned embodiment, the case where the magnet fixing portion 46 of the magnet holder 34 is formed of an elastomeric resin having elasticity capable of compressive deformation has been described. However, the present invention is not limited to this, and the magnet fixing portion 46 may be formed of an elastic body that can be compressed and deformed.

Moreover, in the above-mentioned embodiment, the case where the holding part 47 of the magnet holder 34 was formed with resin whose hardness is higher than the hardness of the magnet fixing part 46 was demonstrated. However, the present invention is not limited to this, and the holding portion 47 and the magnet fixing portion 46 can be formed of the same material.
Furthermore, the magnet holder 34 demonstrated the case where the magnet fixing | fixed part 46 and the holding | maintenance part 47 were formed by 2 color molding with resin. However, the present invention is not limited to this. After the magnet fixing portion 46 and the holding portion 47 are separately formed, the magnet fixing portion 46 and the holding portion 47 may be integrated.

Moreover, in the above-mentioned embodiment, the case where the resolver 26 was used as an apparatus which detects the rotation position of the rotor 5 was demonstrated. However, the present invention is not limited to this, and any device capable of detecting the rotational position of the rotor 5 may be used.
For example, a rotational position detection device using a sensor magnet and a magnetic detection element for detecting a magnetic change of the sensor magnet may be employed instead of the resolver 26. In this case, the magnet holder 34 may be configured to be able to attach a sensor magnet, and a control substrate having a magnetic detection element mounted on the motor case 2 or the bracket 3 may be attached.

  Moreover, in the above-mentioned embodiment, while the positioning hole 56 was formed in the magnet holder 34, the case where the positioning convex part (not shown) which can be fitted to the positioning hole 56 was provided in the magnetizing apparatus not shown was demonstrated. Then, the case where the positioning of the rotor core 32 with respect to the magnetizing device is performed by the positioning hole 56 and the positioning convex portion (not shown) has been described. However, the present invention is not limited to this, and the positioning hole 56 may be formed in a magnetizing device (not shown), and the magnet holder 34 may be provided with a positioning protrusion which can be fitted in the positioning hole 56.

  Moreover, in the above-mentioned embodiment, the case where the positioning hole 56 was formed in a substantially arc shape as viewed from the axial direction so as to be long along the circumferential direction was described. However, the present invention is not limited to this, and the shape of the positioning hole 56 can be arbitrarily determined.

DESCRIPTION OF SYMBOLS 1 ... Brushless motor (motor), 4 ... stator, 5 ... rotor, 10 ... coil, 26 ... resolver (rotational position detection device), 27 ... resolver stator (rotational position detection device), 28 ... resolver rotor (rotational position detection device , 31: rotation axis, 32: rotor core, 33: magnet, 34: magnet holder, 41: magnet storage hole, 42: storage hole main body, 43: air gap, 44: magnet positioning convex (positioning convex), 45 ... A detachment preventing rib, 46 ... a magnet fixing portion, 47 ... a holding portion, 48 ... a fixing portion main body, 49 ... a tip portion, 51 ... a first relief portion (a relief portion), 52 ... a second relief portion (a relief portion), 53 3rd relief part (removal part) 54: rotation shaft outer fitting part 56: positioning hole (positioning part) 57: resolver rotor holding claw (sensor placement part) 58: holding part main body

Claims (8)

With the rotation axis,
A rotor core externally fitted and fixed to the rotating shaft;
A plurality of magnets provided in the rotor core;
A magnet holder for fixing the magnet in the rotor core;
Equipped with
The rotor core has a plurality of magnet storage holes which are formed to be circumferentially long near the outer periphery and in which the magnets are stored.
The magnet housing hole is formed to have a gap at both ends in the circumferential direction, with the magnet housed in the magnet housing hole.
The magnet holder is
A plurality of magnet fixing parts made of an elastic body that can be compressed and deformed, and inserted in a state of being compressed and deformed in each of the air gaps;
A holding portion disposed at one axial end of the rotor core and connecting one end of the plurality of magnet fixing portions;
A rotor characterized by having. The rotor according to claim 1, wherein a positioning convex portion for positioning the magnet in the magnet housing hole is provided in a part of the gap portion. The other end in the axial direction opposite to the holding portion of the rotor core is provided with a detachment preventing rib for preventing detachment of the magnet from the magnet storage hole. The rotor according to item 2. The magnet fixing portion and the holding portion are integrally molded,
The magnet fixing portion is formed of an elastomeric resin,
The rotor according to any one of claims 1 to 3, wherein the holding portion is formed of a resin having a hardness higher than the hardness of the magnet fixing portion. The relief part which permits the elastic deformation of the said magnet fixing part inserted in the said void part is formed in at least any one of the said magnet fixing part and the said void part, The 1st-4th aspect is characterized by the above-mentioned. The rotor of any one of claim 4. The rotor according to any one of claims 1 to 5, wherein the holding portion has a positioning portion for positioning the rotor core with respect to a magnetizing device. A rotor according to any one of claims 1 to 6, and
A stator formed so as to surround the periphery of the rotor and having a coil wound thereon;
A motor characterized in that it comprises. A rotational position detection device for detecting the rotational position of the rotor;
The motor according to claim 7, wherein the holding unit has a sensor placement unit for attaching the rotational position detection device.

Images