WO2022264747A1 - Moteur sans balais - Google Patents

Moteur sans balais Download PDF

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Publication number
WO2022264747A1
WO2022264747A1 PCT/JP2022/020845 JP2022020845W WO2022264747A1 WO 2022264747 A1 WO2022264747 A1 WO 2022264747A1 JP 2022020845 W JP2022020845 W JP 2022020845W WO 2022264747 A1 WO2022264747 A1 WO 2022264747A1
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WO
WIPO (PCT)
Prior art keywords
brushless motor
permanent magnet
rotor
motor according
stator
Prior art date
Application number
PCT/JP2022/020845
Other languages
English (en)
Japanese (ja)
Inventor
渉 横山
肇 寺崎
洋平 河野
省三 川崎
Original Assignee
日立Astemo株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日立Astemo株式会社 filed Critical 日立Astemo株式会社
Publication of WO2022264747A1 publication Critical patent/WO2022264747A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/356—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear making the angular relationship oscillate, e.g. non-homokinetic drive
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
    • H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears

Definitions

  • the present invention relates to brushless motors.
  • This brushless motor has a rotor fixed to the outer circumference of the motor output shaft, and a plurality of magnets, which are permanent magnets, provided on the outer circumference of the rotor core of the rotor.
  • a magnetic sensor which is a rotation detection sensor, is arranged in the axial direction of the axial end face of the magnet. is placed in the right position.
  • the magnetic sensor is arranged so as to partially overlap the end surface of the magnet in the axial direction. is the N pole (or S pole), and the outer side is the S pole (or N pole), the magnetic flux component in the radial direction increases and the magnetic flux component in the axial direction decreases. For this reason, there is a possibility that the detection accuracy of the magnetic sensor that detects the magnetic flux component in the axial direction will be degraded.
  • the present invention has been devised in view of the above-mentioned conventional technical problems, and one of the objects thereof is to provide a brushless motor capable of suppressing costs while ensuring high detection accuracy of the rotation detection sensor.
  • One of the preferred aspects is, among others, a rotation detection sensor that detects the magnetism of a permanent magnet, the rotation detection sensor being spaced apart from the permanent magnet in the rotation axis direction of the rotor and At least a portion of the magnet is arranged radially outside or inside the rotating shaft with respect to the permanent magnet, and detects a magnetic flux component of the permanent magnet in the rotating shaft direction.
  • FIG. 1 is a side view showing a partial longitudinal section of a valve timing control device for an internal combustion engine according to an embodiment of the present invention
  • FIG. FIG. 2 is an exploded perspective view showing components of a speed reduction mechanism and a brushless motor used in the present embodiment
  • 1 is a longitudinal sectional view of a brushless motor used in this embodiment
  • FIG. 4 is an enlarged view of part A in FIG. 3
  • FIG. 6 is a cross-sectional view showing a cross-section of the upper portion of the rotor shown in FIG. 5; It is a schematic diagram showing the mounting positions of three magnetic sensors provided on the circuit board used in the present embodiment.
  • FIG. 3 is a distribution diagram of magnetic flux density of a permanent magnet used in the present embodiment
  • FIG. 1 is a side view showing a partial vertical cross-section of a valve timing control device for an internal combustion engine according to this embodiment
  • FIG. 2 is an exploded view showing components of a speed reduction mechanism and a brushless motor according to this embodiment It is a perspective view.
  • a valve timing control device is applied to the intake side of an internal combustion engine, and as shown in FIGS. a camshaft 2 rotatably supported by the sprocket 1, and a phase changing mechanism disposed between the sprocket 1 and the camshaft 2 for changing the relative rotational phase between the sprocket 1 and the camshaft 2 according to the engine operating state. ing.
  • the sprocket 1 includes an annular sprocket body 1a and a gear that is integrally provided on the outer circumference of the sprocket body 1a and receives rotational force from a crankshaft of an internal combustion engine via a timing chain (not shown) wound around the outside of the sprocket body 1a. a portion 1b;
  • a chain case (not shown) coupled to the cylinder block and cylinder head 01 of the internal combustion engine is provided on the outer periphery of the sprocket 1 .
  • the internal gear 5 is integrally connected to the sprocket body 1a and has a plurality of wavy internal teeth 5a on its inner circumference.
  • the sprocket body 1a is provided with a sliding bearing mechanism 6 between the inner peripheral surface on the side of the camshaft 2 and the outer peripheral surface of the driven member 9, which will be described later.
  • the slide bearing mechanism 6 bears the sprocket 1 relatively rotatably on the outer periphery of the driven member 9 (camshaft 2).
  • a holding plate 8 made of a ferrous metal plate and formed in an annular shape is fixed to the rear end face of the sprocket body 1a on the camshaft 2 side.
  • the holding plate 8 is integrally provided with a stopper projection 8b protruding in the central axis direction at a predetermined position on the inner peripheral surface of the central hole 8a.
  • the stopper convex portion 8b is formed in a substantially inverted trapezoidal shape, and the tip surface thereof is formed in an arcuate shape along the arcuate inner peripheral surface of the stopper concave groove 4b of the adapter 4, which will be described later.
  • the adapter 4 is made of a metal plate and fitted into the central hole 8a of the holding plate 8.
  • the adapter 4 has an insertion hole 4a through which the cylindrical portion 9c of the driven member 9 is inserted, and has a stopper groove 4b at a predetermined position on the outer peripheral surface.
  • the stopper recessed groove 4b is formed in a predetermined range along the outer periphery of the adapter 4, and the stopper protrusions 8b on both side edges in the circumferential direction come into contact with the stopper protrusions 8b from the circumferential direction.
  • the relative rotational position of (the camshaft 2) on the maximum advance side or the maximum retardation side is mechanically restricted.
  • a front plate 15 is provided on the front end surface of the sprocket 1 on the internal gear 5 side. As shown in FIGS. 1 and 2, the front plate 15 is formed by stamping, for example, an iron-based metal plate into an annular shape by press forming. 15a is formed through.
  • the holding plate 8 is also formed with six female threaded holes 8c into which the male threaded portions 7a at the ends of the bolts 7 are screwed.
  • the camshaft 2 has two drive cams per cylinder on its outer circumference that open intake valves (not shown).
  • the camshaft 2 has an insertion hole 2b formed along the inner axial direction from the tip surface of the one end 2a, and a shaft portion 14b of a cam bolt 14, which will be described later, is inserted.
  • a female screw portion 2c is formed on the inner peripheral surface of the insertion hole 2b on the distal end side.
  • the driven member 9 is integrally formed of ferrous metal, and has a disk-shaped main body 9a, as shown in FIGS.
  • a bolt insertion hole 9b into which the shaft portion 14b of the cam bolt 14 is inserted is formed through the disk-shaped main body 9a at the center position.
  • a cylindrical portion 9c protruding toward the camshaft 2 is integrally provided at the edge of the bolt insertion hole 9b.
  • a journal portion 11 that constitutes a part of the slide bearing mechanism 6 is integrally provided on the outer peripheral surface of the disk-shaped main body 9a.
  • the driven member 9 is axially fastened and fixed to the camshaft 2 by a cam bolt 14 with the tip of the cylindrical portion 9c axially fitted into the cylindrical groove of the one end 2a of the camshaft 2 .
  • the slide bearing mechanism 6 includes an annular bearing recess 10 formed on the inner peripheral surface of the sprocket main body 1a, and a bearing recess 10 provided on the outer peripheral surface of the disk-shaped main body 9a. and a journal portion 11 disposed therein.
  • the bearing recess 10 has a sliding bearing surface on its annular bottom surface, and the other end on the side of the camshaft 2 is opened and released to the outside. covered by the inner surface.
  • the journal portion 11 has an annular outer peripheral surface that is slidable on the entire slide bearing surface of the bearing recess portion 10 .
  • the other end surface of the journal portion 11 on the holding plate 8 side in the axial direction is slidable on the inner surface of the inner peripheral portion of the holding plate 8 .
  • the cam bolt 14 includes a substantially cylindrical head portion 14a, a shaft portion 14b integrally fixed to the head portion 14a, and a cam formed on the outer peripheral surface of the shaft portion 14b. and a male threaded portion 14c screwed onto the female threaded portion 2c of the shaft 2 .
  • Each needle roller 34a of the needle bearing 34 is rotatably supported on the outer peripheral surface of the head 14a which has been subjected to heat treatment such as induction hardening.
  • the phase change mechanism comprises a brushless motor 12 arranged on the front end side of the front plate 15, and a cam by reducing the rotational speed transmitted from the brushless motor 12 via an Oldham coupling. and a speed reducer 13 for transmission to the shaft 2 .
  • the speed reducer 13 is provided independently of the brushless motor 12 in the axial direction, and each component is provided inside the sprocket 1 between the holding plate 8 and the front plate 15. placed in containment.
  • the speed reducer 13 includes a cylindrical eccentric shaft 30 partially arranged inside the sprocket body 1a, a ball bearing 31 provided on the outer circumference of the eccentric shaft 30, and provided on the outer circumference of the ball bearing 31, A plurality of rollers 32 rotatably held within the internal teeth 5a of the internal gear 5 and a plurality of rollers 32 integrally provided on the outer peripheral side of the disk-shaped main body 9a of the driven member 9 to hold the plurality of rollers 32 in the rolling direction. and a retainer 33 that permits radial movement while holding.
  • the eccentric shaft 30 includes an eccentric shaft portion 30a arranged on the outer periphery of a needle bearing 34 provided on the outer periphery of the head portion 14a of the cam bolt 14, and a brushless motor of the eccentric shaft portion 30a. and a cylindrical connecting portion 30b integrally provided on the 12 side.
  • the eccentric shaft portion 30a is formed in a cylindrical shape whose axial length is longer than that of the needle bearing 34 in its axial direction. As shown in FIG. 2, the eccentric shaft portion 30a is slightly eccentric with respect to the axis Y of the cam bolt 14 because the thickness t of the eccentric shaft portion 30a varies in the entire circumferential direction.
  • the connecting portion 30b is formed in a substantially circular shape with a uniform thickness, and is slightly thicker than the eccentric shaft portion 30a.
  • the connecting portion 30b protrudes toward the brushless motor 12 from the inside of the sprocket body 1a through the insertion hole 15a of the front plate 15. As shown in FIG.
  • the connecting portion 30b constitutes an Oldham coupling together with an intermediate member 28 of the brushless motor 12, which will be described later.
  • the connecting portion 30b is formed therein with a fitting hole having a width across flats into which the cylindrical base portion 28a of the intermediate member 28 can be fitted from the axial direction.
  • the connecting portion 30b is provided with a pair of crescent-shaped convex portions forming a width across flats at positions approximately 180° in the circumferential direction of the inner peripheral surface of the fitting hole.
  • a pair of key grooves 21d and 21e into which the two transmission keys 28b and 28c of the cylindrical base 28a can be fitted are formed at radially symmetrical positions at substantially central positions of the pair of projections.
  • Each of the key grooves 21d and 21e is formed in a rectangular shape similar to the transmission keys 28b and 28c, and its depth is set to approximately the same length as the width of each of the transmission keys 28b and 28c.
  • the pair of projections functions as a suppressing portion that suppresses excessive supply of lubricating oil supplied into the speed reducer 13 from a lubricating oil supply mechanism, which will be described later, to the Oldham's coupling.
  • the needle bearing 34 is fixed to a plurality of needle rollers rolling on the outer peripheral surface of the head portion 14a of the cam bolt 14 and to a step surface formed on the inner peripheral surface of the eccentric shaft portion 21a. a cylindrical shell having a plurality of grooves in which it is rollably retained.
  • the ball bearings 31 are arranged in such a manner that they substantially overlap each other at the radial position of the needle bearings 34 .
  • the ball bearing 31 is composed of an inner ring 31a, an outer ring 31b, balls interposed between the two rings, and a cage for holding the balls.
  • the inner ring 31a is formed to have a radial thickness larger than that of the outer ring 31b, and is press-fitted and fixed to the outer peripheral surface of the eccentric shaft portion 21a.
  • the outer ring 31b is in a free state without being fixed in the axial direction. That is, one end surface of the outer ring 31b on the brushless motor 12 side in the axial direction faces the inner surface of the front plate 15 with a small clearance therebetween. The other end surface of the outer ring 31b in the axial direction also faces the rear surface of the disk-shaped main body 9a of the driven member 9 facing thereto with a small clearance therebetween.
  • the outer ring 31b is in contact with the outer peripheral surface so that the outer peripheral surface of each roller 32 can roll.
  • An annular clearance is formed between the outer peripheral surface of the outer ring 31 b and the inner surface of the retainer 33 . Therefore, the ball bearing 31 as a whole can eccentrically move in the radial direction with the eccentric rotation of the eccentric shaft portion 21a through the clearance.
  • the retainer 33 is formed in a cylindrical shape and is provided integrally with the outer peripheral portion of the disk-shaped main body 9a. That is, the retainer 33 protrudes toward the front plate 15 from the base side of the journal portion 11 of the disk-shaped main body 9a.
  • the retainer 33 has a plurality of roller holding holes 33a formed along the axial direction for holding the plurality of rollers 32 so that they can roll.
  • the roller holding holes 33a are provided at equal intervals in the circumferential direction of the retainer 33, and are formed in a rectangular shape elongated in the front-rear direction with their tip ends closed.
  • the total number of roller holding holes 33a (the number of rollers 32) is smaller than the total number of internal teeth 5a of the internal gear 5, thereby obtaining a predetermined reduction ratio. ing.
  • Each roller 32 is fitted into the internal tooth 5a of the internal gear 5 while moving in the radial direction with the eccentric motion of the ball bearing 31, and rocks in the radial direction while being guided in the circumferential direction by both side edges of each roller holding hole 33a. It is designed to move.
  • the reduction gear 13 and the Oldham's coupling are supplied with lubricating oil via a lubricating oil supply mechanism.
  • the lubricating oil supply mechanism includes an oil supply passage 35 formed axially inside the camshaft 2 and an oil supply passage 35 formed through the inner peripheral portion of the adapter 4 in the width direction. 35, and a supply hole 37 formed through the disk-shaped main body 9a in the width direction, one end communicating with the introduction passage hole 36, and the other end directed toward the needle bearing 34 of the speed reducer 13. and an oil pump 38 that supplies lubricating oil to the oil supply passage 35 .
  • FIG. 3 is a vertical cross-sectional view of a brushless motor used in this embodiment
  • FIG. 4 is an enlarged view of part A in FIG.
  • the brushless motor 12 is a DC motor, and as shown in FIGS. 1 to 4, has a bottomed cylindrical motor housing 16 fixed to the chain case and a A stator (stator) 17, a motor output shaft 18 arranged on the inner peripheral side of the stator 17, a rotor 19 fixed to the outer periphery of the motor output shaft 18, and a motor housing 16 provided on the opposite side of the sprocket 1. and a control mechanism 20 .
  • the motor housing 16 is formed, for example, by bending an iron-based metal plate into a cup shape, and a stator housing space S for housing the stator 17 and the like is formed therein.
  • the motor housing 16 is formed with a through hole 16b through which the motor output shaft 18 is inserted, substantially in the center of the bottom wall 16a on the speed reducer 13 side.
  • the through hole 16b is formed inside a tubular portion 16c formed by bending the center of the bottom wall 16a into a tubular shape.
  • a cylindrical bearing holding portion 16g for holding a first ball bearing 29a, which is a first bearing portion to be described later, is provided near the cylindrical portion 16c of the bottom wall 16a.
  • the motor housing 16 is integrally provided with a flange portion 16d projecting radially outward on the outer periphery of the open end of the rear end portion.
  • the flange portion 16d is integrally provided with three bracket pieces 16e at approximately 120° positions in the circumferential direction.
  • Bolt insertion holes 16f into which three bolts 21 are inserted are formed through the three bracket pieces 16e.
  • the number of bracket pieces 16e may be three or more.
  • Each bolt 21 fastens and fixes the motor housing 16 and a later-described casing 40 of the control mechanism 20 together, and also fixes them to a chain case (not shown).
  • each bolt 21 has a male threaded portion 21b on the outer periphery of the tip portion on the side of the eccentric shaft portion 21a, which is fastened to a female threaded portion of the chain case, thereby fixing the motor housing 16 and the casing 40 to the chain case.
  • the stator 17 includes a stator core (iron core) 17a and multi-phase (three-phase U, V, W) coils 17b wound around the outer periphery of the stator core 17a.
  • the stator core 17a is formed by laminating a number of steel plates, and has a ring-shaped yoke portion (not shown) and a plurality of teeth projecting inward from the yoke portion.
  • the coil 17b is wound around a plurality of teeth via insulators.
  • the motor output shaft 18 is made of, for example, an iron-based metal material, and one end 18a on the side of the speed reducer 13 in the rotation axis direction protrudes from the through hole 16b via an oil seal 22, which will be described later.
  • One end portion 18a of the motor output shaft 18 has a width across flat portion (not shown) formed along the tangential direction on the outer surface of the motor output shaft 18. are formed with fitting grooves. As shown in FIG. 1, a stopper member 50 for restricting the movement of the intermediate member 28 toward the cam bolt 14 is radially fitted and fixed in both fitting grooves. Also, the one end portion 18a is supported on the motor housing 16 by a first ball bearing 29a held in the bearing holding portion 16g.
  • the first ball bearing 29a has a general structure, and includes an outer ring fixed to the inner peripheral surface of the bearing holding portion 16g, an inner ring fixed to the outer peripheral surface of the one end portion 18a of the motor output shaft 18, and the two wheels. and a plurality of balls provided via a cage therebetween.
  • the other end 18b of the motor output shaft 18 is rotatably supported by a second ball bearing 29b provided in the casing 40 of the control mechanism 20.
  • the second ball bearing 29b has a general structure similar to that of the first ball bearing 29b. It has an inner ring into which the outer peripheral surface of the portion 18b is press-fitted, and a plurality of balls provided between the two rings via a cage.
  • the oil seal 22 has a general structure, the outer peripheral surface of which is press-fitted into the inner peripheral surface of the through hole 16b, while the inner peripheral seal piece is pressed against the outer peripheral surface of the one end portion 18a of the motor output shaft 18 by a backup spring. They are in slidable contact. Thereby, the oil seal 22 restricts the inflow of oil from the speed reducer 13 into the motor housing 16 .
  • one end 18a of the motor output shaft 18 is arranged close to the head 14a of the cam bolt 14 with a slight gap from the rotation axis direction.
  • the one end portion 18a can be axially inserted into a hexagonal groove formed on the front end surface of the head portion 14a including the stopper member 50. As shown in FIG.
  • the stopper member 50 is formed in a C-ring shape, and is elastically deformable in the radially expanding direction and the radially contracting direction by its own elastic force.
  • An intermediate member 28 is provided at one end portion 18a of the motor output shaft 18 .
  • the intermediate member 28 constitutes a part of an Oldham coupling which is a joint connected to the speed reducer 13, and as shown in FIG. It has a base 28a.
  • the cylindrical base portion 28a has a pair of flat surfaces on both sides of the circular outer surface, that is, at 180° positions in the circumferential direction. ing.
  • a through hole 28d into which the width across flats portion of the one end portion 18a of the motor output shaft 18 is inserted is formed at the central position of the cylindrical base portion 28a.
  • the through hole 28d has a circular inner peripheral surface formed with a pair of opposing surfaces extending in the radial direction from the rotation axis of the motor output shaft 18 and having a width across flats.
  • the through-hole 28d is formed in an oval shape that is long in the radial direction and similar to the outer shape of the cylindrical base portion 28a. Therefore, the intermediate member 28 can move radially (up and down in FIGS. 1 and 2) with respect to the one end 18a of the motor output shaft 18 via the oblong through hole 28d.
  • the tubular base portion 28a is provided with the two transmission keys 28b and 28c described above at approximately the center position of the pair of flat portions in the longitudinal direction (vertical direction in FIG. 1).
  • Each transmission key 28b, 28c is formed in a substantially rectangular plate shape and protrudes radially outward from two plane portions of the cylindrical base portion 28a.
  • FIG. 5 is a perspective view of the rotor used in this embodiment
  • FIG. 6 is a cross-sectional view showing the axially upper portion of the rotor shown in FIG.
  • the rotor 19 is arranged on the inner peripheral side of the stator 17, and includes an annular rotor core 23 fixed to the outer periphery of the motor output shaft 18 and an outer peripheral portion 23a of the rotor core 23. and eight permanent magnets 25 inserted and held in each of the holding holes 24 (eight in this embodiment).
  • the rotor core 23 and the permanent magnets 25 are provided coaxially with respect to the motor output shaft 18 .
  • the rotor core 23 is integrally formed of a metal material and has a substantially cylindrical outer peripheral portion 23 a and a cylindrical inner peripheral portion 23 b fixed to the motor output shaft 18 .
  • An intermediate portion between the outer peripheral portion 23a and the inner peripheral portion 23b is formed in a honeycomb shape.
  • the outer peripheral portion 23a has a shape in which eight arcuate blocks B are annularly connected along the circumferential direction, and the inner peripheral surface 23c is formed in an octagonal shape.
  • a gap having a substantially triangular cross-section is formed outside between the blocks B and filled with a covering portion 26 made of a synthetic resin material, which will be described later.
  • An insertion hole 23d into which the motor output shaft 18 is inserted and fixed is formed through the inner peripheral portion 23b in the central axial direction.
  • Each holding hole 24 is formed through each block B portion of the rotor core outer peripheral portion 23a along the inner axial direction.
  • Each holding hole 24 is formed in an elongated shape extending substantially along the circumferential direction when viewed from the front, and is formed in a substantially rectangular shape when viewed through from the radially outer side.
  • the holding hole 24 has a uniform cross-sectional area penetrating from one end opening edge 24a on the control mechanism 20 side to the other end opening edge 24b on the reduction gear 13 side in the axial direction.
  • each permanent magnet 25 is made of a general composite alloy material (rare earth sintered magnet) such as neodymium and formed into a substantially square plate shape with a predetermined thickness.
  • the permanent magnets 25 are each formed in a plate-like shape with sides having the same length.
  • each side means that the tolerance of the lengths in the axial direction and the circumferential direction is within a range of ⁇ 0.2 mm.
  • Each side of the permanent magnet 25 is shorter than the widthwise length of the holding hole 24.
  • both side surfaces and the holding hole facing the both side surfaces are formed.
  • a gap is formed between the opposite inner surfaces of 24 in the width direction.
  • each permanent magnet 25 When the rotational axis of the rotor 19 is taken as the axial direction, each permanent magnet 25 has one end on the side of the control mechanism 20 in the axial direction forming a projecting portion 25a projecting from one end opening edge 24a of each holding hole 24. there is Further, each permanent magnet 25 has a recessed portion 25b recessed inside the holding hole 24 from the other end opening edge 24b of each holding hole 24 at the other end on the speed reducer 13 side in the axial direction.
  • the amount of protrusion of the protrusion 25a that is, the length L from the one end opening edge 24a of the holding hole 24 to the tip end surface is approximately 2 mm in this embodiment.
  • the recessed portion 25b has a recessed amount, that is, a length L1 from the other end opening edge 24b of the holding hole 24 to the rear end face of the recessed portion 25b, which is approximately 1 mm in this embodiment.
  • the outer peripheral portion 23a of the rotor core 23 is entirely covered with a covering portion 26 made of a synthetic resin material, which is a non-magnetic material, on the protruding portion 25a side and the receding portion 25b side.
  • the covering portion 26 is annular so as to cover the entire outer peripheral surface of each projecting portion 25a so as to bury each projecting portion 25a inside.
  • the covering portion 26 is filled into the holding hole 24 from the other end opening edge 24b of the holding hole 24 so as to cover the recessed portions 25b, and is formed in an annular shape as a whole.
  • a portion 26a of the covering portion 26 is also filled in the triangular gap between the blocks B of the outer peripheral portion 23a, and the both side surfaces of the permanent magnet 25 in the circumferential direction and the opposite surfaces of the holding hole 24 in the width direction are covered with the covering portion 26.
  • the gaps between are also filled.
  • the covering portion 26 is filled in the rear end opening of the holding hole 24 so as to cover the recessed portion 25b. are provided with holes 27 communicating with each other.
  • the holes 27 are arranged in advance in the molding die when the synthetic resin material is molded on the outer peripheral portion 23a of the rotor core 23 by, for example, injection molding. It was formed on the trace after the pin was pulled out after molding.
  • the control mechanism 20 has a box-shaped casing 40 made of, for example, a synthetic resin material (non-magnetic material). As shown in FIG. 3, the casing 40 has a rectangular partition wall 40a arranged on the motor housing 16 side, and a rectangular frame-shaped peripheral wall 40b rising from the outer peripheral edge of the partition wall 40a. There is Further, a substrate accommodation space S1 is formed inside surrounded by the partition wall 40a and the peripheral wall 40b.
  • the partition wall 40a is integrally provided with a cylindrical tubular portion 41 in the center, and is integrally provided with four small-diameter cylindrical bosses 40e at the four corners of the inner surface.
  • Each of the columnar bosses 40e has a female threaded hole (not shown) in which four screws (not shown) for fixing the square circuit board 42 are screwed at the tip.
  • the partition wall 40a is provided with a first recess 43a at a portion axially facing a magnetic sensor 45, which will be described later, and at a portion facing a projecting portion 25a of the permanent magnet 25. is provided with a second recess 43b.
  • the first recess 43a and the second recess 43b partially overlap in the radial direction, that is, partially overlap in the radial direction.
  • the first concave portion 43a is formed in the shape of an annular groove with a radial width longer than the radial length of the magnetic sensor 45 so that the magnetic sensor 45 can enter.
  • the second recess 43b is also formed in an annular groove shape, and its radial width is formed sufficiently larger than the thickness width of the protrusion 25a, so that the protrusion 25a can enter. It's becoming
  • the circuit board 42 is housed in the board housing space S1, and a conductive circuit (not shown) such as a bus bar for supplying power to the brushless motor 12 is arranged inside. Further, one side of the circuit board 42 is provided with hall terminals that are coupled to a plurality of terminal strips of a connector 44 to be described later by soldering.
  • the circuit board 42 has an insertion hole 42a through which the cylindrical portion 41 can be inserted, and four small-diameter screw insertion holes through which screws (not shown) are inserted at the four corners. formed.
  • the board accommodation space S1 also contains three magnetic sensors 45a, 45b, and 45c, which are rotation detection sensors that conduct with the circuit board 42 and control the drive of the brushless motor 12, and an aluminum electrolytic sensor.
  • a plurality of electronic components such as a capacitor, a normal coil, a common coil, and a plurality of ceramic capacitors are housed and arranged.
  • FIG. 7 is a schematic diagram showing the attachment positions of the magnetic sensors provided on the circuit board used in this embodiment.
  • a V-phase magnetic sensor 45b provided between the V-phase and the V-phase and a W-phase magnetic sensor 45c provided between the V-phase and the W-phase are provided. Further, each of the magnetic sensors 45a to 45c detects the magnetic flux component (magnetic flux density) in the axial direction of the permanent magnet 25 instead of the magnetic flux component in the radial direction, and determines whether the magnetic flux density is positive or negative. It's becoming
  • the magnetic sensors 45a to 45c are arranged on the circuit board 42 at positions separated from the permanent magnets 25 in the rotation axis direction of the rotor 19 and radially. It is provided at a position shifted to the outside (arrow side) of the In other words, the magnets 25 are arranged at positions radially outwardly displaced from the circumferential central positions of the permanent magnets 25 . This is because, as will be described later, the characteristic of detecting magnetic flux components (magnetic flux densities) in the axial direction of the magnetic sensors 45a to 45c is to enhance the detection accuracy by the unique arrangement configuration with respect to the permanent magnets 25.
  • each of the magnetic sensors 45a to 45c is arranged so as to straddle an annular gap C between the inner peripheral surface of the stator 17 and the outer peripheral surface of the rotor 19, and the sensor center P1 in the radial direction is positioned in the annular gap C. doing.
  • Each of the magnetic sensors 45a to 45c is partially arranged between the coils 17b at the mounting position in the circumferential direction of the stator 17, and substantially faces the projecting portion 25a of the permanent magnet 25 in the axial direction. placed in position.
  • the tubular portion 41 is formed in a substantially cylindrical shape with a bottom, and one axial end and the other axial end face the stator housing space S and the substrate housing space S1, respectively, with the partition wall 40a as the center. That is, one end is arranged in the stator accommodation space S, and the other end is arranged in the substrate accommodation space S1. Further, the cylindrical portion 41 has a bearing holding groove 41a for accommodating and holding the second ball bearing 29b therein.
  • the peripheral wall 40b is integrally provided with a connector 44 that serves as both a signal and a power supply on the outer periphery.
  • the connector 44 is formed in the shape of a box, and a pair of one end portions 44a of terminal strips are arranged therein.
  • the other end portion of the terminal strip (not shown) located in the board accommodation space S1 is connected to the hole terminal of the conduction circuit of the circuit board 42 by soldering.
  • a pair of one end portions 44a located in the connector 44 of the terminal piece is partially connected to an engine control unit (ECU) (not shown) via a female terminal to a battery as a power source.
  • ECU engine control unit
  • Other parts are adapted to output information signals such as rotation angle signals detected by the magnetic sensors 45a to 45c to the ECU.
  • a cover member 46 is attached to the outer periphery of the peripheral wall 40 b on the side opposite to the motor housing 16 .
  • the cover member 46 is formed of, for example, an aluminum alloy material in a plate-like square shape, and an outer peripheral portion 46a bent in a crank shape toward the casing 40 is fixed to a peripheral wall 40b of the casing 40 by a predetermined fixing means. It has become so.
  • the ECU detects the current engine operating status based on information signals from various sensors (not shown) such as a crank angle sensor, air flow meter, water temperature sensor, and accelerator position sensor, and controls the engine based on this. ing.
  • the ECU controls the rotation of the motor output shaft 18 by energizing the coil 17b of the brushless motor 12 based on the information signals and signals from the magnetic sensor 45 and the like.
  • the reduction gear 13 controls the relative rotational phase of the camshaft 2 with respect to the timing sprocket 1 .
  • the control current from the control unit is applied to each coil 17b of the brushless motor 12, and the motor output shaft 18 is driven to rotate forward and backward.
  • the rotational force of the motor output shaft 18 is transmitted to the eccentric shaft 30 via the Oldham's coupling, and reduced rotational force is transmitted to the camshaft 2 by the operation of the speed reducer 13 .
  • the camshaft 2 rotates forward and backward relative to the timing sprocket 1 to convert the relative rotation phase. Therefore, the opening/closing timing of each intake valve is controlled to advance or retard.
  • each of the magnetic sensors 45a to 45c uses sensors that detect axial magnetic flux components, which are cheaper than sensors that detect radial magnetic flux components. Therefore, the cost of the magnetic sensors 45a to 45c themselves can be reduced.
  • the magnetic sensors 45a to 45c are Hall ICs, and the sensor cores of the Hall ICs are plate-shaped. Magnetic flux passing through the plate-shaped sensor core in the thickness direction is detected.
  • the magnetic sensors 45a to 45c are arranged at positions separated from the permanent magnets 25 in the rotation axis direction of the rotor 19 and at positions outside the rotor 19 in the radial direction. That is, each of the magnetic sensors 45a to 45c is provided at a position shifted outward in the radial direction of the rotor 19 with the permanent magnet 25 as the center. As a result, the magnetic flux density of the permanent magnet 25 can easily reach the peak value, so that the detection performance is improved and the magnetic sensors 45a to 45c are less susceptible to variations in axial position.
  • FIG. 8 is an enlarged view showing nine radial mounting positions (measurement positions) of one magnetic sensor with respect to a permanent magnet. 2 is a graph showing the measurement of the directional component).
  • the inventors of the present application have arranged the attachment positions of the magnetic sensors 45 (45a to 45c) provided on the circuit board 42 with respect to the permanent magnets 25 in the radial direction of the rotor 19 from the center position of the permanent magnets 25.
  • the magnetic flux density (magnetic flux component in the axial direction) was determined to be positive or negative by dividing it into 9 mounting positions (measurement positions) indicated by black dots between the predetermined inner side and the predetermined outer side.
  • the determination results of the magnetic flux density (T) obtained at each of the nine measurement positions of the magnetic sensor 45 are the magnetic flux density T The peak value of becomes small, and 0 crosses at an unnecessary place. Therefore, at this position, the possibility of erroneous detection by the magnetic sensor 45 may increase.
  • the inner and outer measuring positions I1 to I4 and the outer measuring positions O1 to O4 which are the farthest from the permanent magnet 25, are too far apart, resulting in an axial magnetic flux component was found to be weaker (the peak value was smaller). Also, when the magnetic sensor 45 is too close to the coil 17b as in the outer measurement position O4, it is likely to be affected by the magnetic flux component generated from the coil 17b when the coil 17b is energized. may become
  • the peak value of the magnetic flux density T is high and the waveform is stable.
  • the peak values are highest at the inner and outer measurement positions I2 and O2.
  • Fig. 10 is a distribution diagram of the magnetic flux density of a permanent magnet.
  • the permanent magnet 25 as shown in the magnetic flux density distribution diagram of FIG. It can be seen that the Q region radially outward from the center axis P or the radially inner R region is sufficiently higher than the P region.
  • Positioning the magnetic sensor 45 radially outward from the permanent magnet 25 rather than radially inward reduces angular errors due to variations in mounting of the magnetic sensor 45, thereby increasing the detection accuracy. can.
  • the mounting angle error of the three magnetic sensors 45a to 45c is likely to occur.
  • Each of the magnetic sensors 45a to 45c is attached to the radially outer measurement position O2, and as shown in FIG. and the coil 17b.
  • the peak value of the magnetic flux component in the axial direction of the permanent magnet 25 is high, and the influence of the magnetic flux component generated from the coil 17b is reduced.
  • the detection accuracy of each of the magnetic sensors 45a to 45c is improved, and stable detection performance can be obtained.
  • each of the magnetic sensors 45a to 45c is mounted at a position (measurement position O2) that straddles the annular gap C between the rotor 19 and the stator 17 in the radial direction.
  • 25 is the position where the peak value of the magnetic flux density is the highest, the detection performance of each of the magnetic sensors 45a to 45c is enhanced.
  • the magnetic sensors 45a to 45c are partly arranged between the coils 17b at the mounting positions in the circumferential direction of the stator 17, the influence of the magnetic flux of the coils 17b can be sufficiently avoided. Higher control accuracy.
  • the magnetic sensors 45a to 45c are provided at positions substantially facing the protruding portions 25a of the permanent magnets 25 in the axial direction, the magnetism of the protruding portions 25a can be detected, resulting in high detection accuracy.
  • the first recessed portion 43a provided in the partition wall 40a is made to function as a relief portion so that the magnetic sensors 45a to 45c can be moved inwardly of the first recessed portion 43a. Therefore, the distance between each of the magnetic sensors 45a to 45c and the projecting portion 25a of the permanent magnet 25 facing in the axial direction can be shortened. As a result, the detection accuracy of the magnetism of the permanent magnet 25 by each of the magnetic sensors 45a to 45c is improved.
  • the second recessed portion 43b provided in the partition wall 40a can be made to function as a relief portion for the projecting portion 25a of the permanent magnet 25, so that the projecting portion 25a can be moved into the second recessed portion 43b.
  • the projecting portion 25a of the permanent magnet 25 can be brought closer to the magnetic sensors 45a to 45c, so that the magnetism detection accuracy of the permanent magnet 25 by the magnetic sensors 45a to 45c is further increased.
  • the axial distance between the permanent magnet 25 and the magnetic sensors 45a to 45c can be reduced by the first concave portion 43a and the second concave portion 43b, so that the entire brushless motor can be shortened in the axial direction.
  • each permanent magnet 25 protrudes from one end opening edge 24a of each holding hole 24, and each magnetic sensor 45a to 45c is arranged at a substantially axial position of each protruding portion 25a.
  • the torque characteristic increased by the projecting portion 25a of the permanent magnet 25 can be reduced by adjusting the number of coil windings. can also be easily reduced.
  • the amount of protrusion L of the projecting portion 25a and the amount of recession L1 of the recessed portion 25b are relatively determined according to the induced voltage change rate. It is only necessary to set the retreat amount L1.
  • an increase in the induced voltage can be suppressed by appropriately determining the receding amount L1 of the receding portion 25b while considering the induced voltage increase rate due to the protruding amount L of the protruding portion 25a. This makes it possible to reduce changes in the torque characteristics of the motor.
  • the induced voltage increase rate due to the protruding portion 25a can be easily reduced by simply providing the recessed portion 25b, which facilitates motor design and improves manufacturing efficiency.
  • the increase in the torque characteristic of the motor output due to the projecting portion 25a can be reduced by the recessed portion 25b.
  • the shorter length makes it easier to balance torque characteristics.
  • the permanent magnet 25 is covered with a covering portion 26 made of a synthetic resin material on the front and back of the projecting portion 25a and the receding portion 25b in the axial direction, and the holding hole 24 is also filled with the covering portion 26 to be covered. Therefore, since the positional displacement of the permanent magnets 25 is suppressed, the magnetic field can be stabilized, and cracking and scattering of the permanent magnets 25 due to impact can be suppressed.
  • the permanent magnet 25 can be effectively dissipated.
  • the weight can be reduced, and the effect of stirring the surrounding air is further enhanced with the rotation of the rotor 19, so that the heat dissipation effect for each permanent magnet 25 is further enhanced.
  • the reduction in the magnetic force of each permanent magnet 25 due to heat can be suppressed, so that the rotation of the motor can be stabilized.
  • the present invention is not limited to the configuration of the above-described embodiment. It may be the outer measurement position O3 where the density T is relatively high, or it may be the inner measurement position I3.
  • first recess 43a of the partition wall 40a in an arcuate groove shape only in the portion where the three magnetic sensors 45a to 45c are formed instead of the annular groove shape. By doing so, the rigidity of the partition wall 40a can be increased.
  • the lengths of the projecting portions 25a and the retracting portions 25b of the permanent magnets 25 are relatively determined according to the specifications of the brushless motor 12, the magnitude of the magnetic force, and the like. is possible.
  • Brushless motor 12 includes not only valve timing control devices for internal combustion engines, but also various vehicle motors such as power steering motors, power window motors, sunroof motors, and power seat motors, as well as home appliances such as air conditioners. It can also be applied to motors used in products.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Valve Device For Special Equipments (AREA)
  • Brushless Motors (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Abstract

Ce moteur sans balais comprend : un stator (17) qui est fixé à la périphérie interne d'un carter de moteur (16) et qui comporte une bobine (17b) enroulée sur un noyau de stator (17a); un rotor (19) qui est fixé à un arbre de sortie moteur de bobine de stator (18); un rotor (19) qui comporte un noyau de rotor (23) disposé à l'intérieur du stator et un aimant permanent (25) disposé dans le noyau de rotor; et un capteur magnétique (45) qui détecte le champ magnétique de l'aimant permanent, le capteur magnétique étant disposé au niveau d'une position de mesure (2) qui est à distance de l'aimant permanent dans la direction de l'axe de rotation du rotor et qui est sur le côté extérieur dans le sens radial, et détecte une composante de flux magnétique dans la direction axiale de l'aimant permanent.　Ainsi, il est possible de supprimer une augmentation du coût tout en garantissant une haute précision de détection d'un capteur magnétique.
PCT/JP2022/020845 2021-06-14 2022-05-19 Moteur sans balais WO2022264747A1 (fr)

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JP2021098405A JP2024105747A (ja) 2021-06-14 2021-06-14 ブラシレスモータ
JP2021-098405 2021-06-14

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0562182U (ja) * 1992-01-28 1993-08-13 国産電機株式会社 ブラシレス直流電動機
JP2010263697A (ja) * 2009-05-07 2010-11-18 Denso Corp 電動機
JP2012244791A (ja) * 2011-05-20 2012-12-10 Seiko Epson Corp コアレス電気機械装置及びコアレス電気機械装置の製造方法
JP2015015872A (ja) * 2013-07-08 2015-01-22 ヤマハ発動機株式会社 回転電気機械及び鞍乗型車両
JP2015127652A (ja) * 2013-12-27 2015-07-09 マブチモーター株式会社 回転検出装置およびモータ
JP2016010294A (ja) * 2014-06-26 2016-01-18 日本電産株式会社 モータ

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0562182U (ja) * 1992-01-28 1993-08-13 国産電機株式会社 ブラシレス直流電動機
JP2010263697A (ja) * 2009-05-07 2010-11-18 Denso Corp 電動機
JP2012244791A (ja) * 2011-05-20 2012-12-10 Seiko Epson Corp コアレス電気機械装置及びコアレス電気機械装置の製造方法
JP2015015872A (ja) * 2013-07-08 2015-01-22 ヤマハ発動機株式会社 回転電気機械及び鞍乗型車両
JP2015127652A (ja) * 2013-12-27 2015-07-09 マブチモーター株式会社 回転検出装置およびモータ
JP2016010294A (ja) * 2014-06-26 2016-01-18 日本電産株式会社 モータ

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