JP2002044927A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless motor capable of exactly detecting a rotational angle of an outer rotor using a simple structure. SOLUTION: In the brushless motor M, consisting of an inner stator 580, an outer rotor 550 that rotates around the external periphery of the inner stator and a magnetic sensor 590 that detects a rotational position of the outer rotor 550, with the outer rotor 550 comprising a flywheel 571 having a cylindrical rotor-core unit 573; a plurality of driving magnets 572 disposed at the internal peripheral surface of the rotor-core unit 573; and a flange 573a; that is outwardly expanded at the end of an opening of the rotor-core unit 573. The magnetic sensor 590 is disposed on a magnetic path, that is formed in the gap between the flange 573a and the drive magnets 572.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor, and more particularly, to a brushless motor capable of accurately detecting the rotation angle of a rotor with a simple structure.

[0002]

2. Description of the Related Art In a brushless motor, it is necessary to control the timing of a current flowing through a stator coil in accordance with a relative position between a rotor and a stator.

In order to detect the rotation angle of the rotor, a magnet for detecting the rotation angle has conventionally been provided separately from the drive magnet provided on the rotor. On the other hand, in Japanese Patent Application Laid-Open No. Hei 8-116657, in a brushless motor having an outer rotor structure in which a rotor rotates around a stator, angle detection is performed by detecting a magnetic field of a driving magnet fixed to the outer rotor with a magnetic sensor. There has been proposed a structure in which the magnet for use is abolished.

[0004]

The drive magnet provided on the outer rotor is required to have a function of causing its magnetic field to act strongly on the magnetic poles of the inner stator. However, in a brushless motor having an outer rotor structure, a magnetic field is required. Since the sensor is located outside the outer rotor,
The angle detecting magnet is required to have a function in which the magnetic field strongly acts on the outside of the outer rotor.

[0005] Therefore, in order to make the driving magnet function also as an angle detecting magnet, it is necessary that the driving magnet simultaneously satisfies the above conflicting conditions. For this reason, in the above-described related art, there is a problem that the shape of the driving magnet is complicated, which causes a decrease in productivity and an increase in cost.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a brushless motor capable of accurately detecting the rotation angle of the outer rotor with a simple structure.

[0007]

In order to achieve the above-mentioned object, the present invention provides a brushless motor including a stator, an outer rotor rotating around the outer periphery thereof, and a magnetic sensor for detecting a rotational position of the outer rotor. Wherein the outer rotor includes a flywheel having a cylindrical rotor core, a plurality of drive magnets disposed on an inner peripheral surface of the rotor core, and a flange that extends outward at an open end of the rotor core. The magnetic sensor is disposed on a magnetic path formed in a gap between the flange and the driving magnet.

According to the above feature, a sufficient magnetic action can be ensured between the outer magnetic sensor and the drive magnet while securing a strong magnetic action between the drive magnet and the stator. Therefore, the rotation position can be accurately detected by the magnetic sensor while the drive magnet also functions as the angle detection magnet without mounting the angle detection magnet.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of an electric motorcycle equipped with a brushless motor according to the present invention, which shows an electric traveling function of traveling by driving force of the brushless motor and a human traveling function of traveling by human power (pedal force) input from a pedal. Have.

A front portion of the vehicle body and a rear portion of the vehicle body are connected via a vehicle body frame 1, and a seat post 2 is erected upward from a central portion of the vehicle body frame 1. A seat hype 15 is inserted into the seat post 2, and a seat 8 in which a tail lamp 12 and left and right turn signals 13 are integrally formed is provided at an upper end of the seat hype 15.

At the end of the body frame 1, a headlight 1
1 is provided so as to protrude forward, and a headlight 11 is provided.
A front carrier 12 is mounted on an upper part of the front carrier. A front fork 3 is pivotally supported on a head pipe 16 at the front end of the body frame. A handle 9 is attached to an upper end of the front fork 3, while a front wheel FW is pivotally supported at a lower end. The left and right sides of the handle 9 are provided with front and rear wheel brake levers 14, and a right grip (not shown) also serves as an accelerator grip 58 (see FIG. 6).

An electric unit 5 is provided below the body frame 1.
Are fixed, and the rear wheel RW is supported by the transmission unit 6. The electric unit 5 has a built-in brushless motor M of the present invention, and has a crankshaft 52 through a crank 517.
The pedaling force input to 0 or the driving force generated by the brushless motor M is transmitted to the transmission unit 6.

The transmission unit 6 is fixed to the vehicle body frame 1 via a U-shaped frame 4. The drive sprocket 514 of the electric unit 5 and the driven sprocket 614 of the transmission unit are connected by a chain 516. The drive pulley 540 of the electric unit 5 and the driven pulley 610 of the transmission unit 6 that constitute the automatic transmission are connected by a V-belt 543. A flip-up center stand 19 is provided below the electric unit 5.

FIG. 2 shows a crankshaft 52 of the electric unit 5.
0 is a cross-sectional view in a plane perpendicular to the drive shaft 521,
The same reference numerals as those described above denote the same or equivalent parts.

The case of the electric unit 5 is a case body 5
12 and an L case 513 and an R case 511 which cover the left and right thereof. One end of the crankshaft 520 is supported by the R case 511 via the bearing 531, and the other end is supported by the L case 513 via the bearing 532. The drive shaft 521 includes bearings 533 and 53
4 through a case body 512.

At one end of the crankshaft 520, the crank 5
17 is fixed outside the R case 511, and further, a driving sprocket 514 is supported via a one-way ratchet 515. A chain 516 is hung on the drive sprocket 514. One end of the drive shaft 521 is provided with a brushless motor M having this as a rotation axis, and the other end of the drive shaft 521 is provided with a drive pulley 540 of the automatic transmission.

The brushless motor M will be described later with reference to FIGS.
, An inner stator 580 including a stator core 581 and an exciting coil 582, a bobbin-shaped flywheel 571 having a ring-shaped rotor core 573 as a main part, and inner circumferential surfaces of the rotor core 573. An outer rotor 570 including a plurality of drive magnets 572 disposed along the drive magnet 572;
Of the outer rotor 570 based on the magnetic field of
Magnetic sensor 59 for detecting a relative position with respect to 80
0.

The driving pulley 540 includes a driving shaft 521
And a movable pulley piece 541 that is slidable in the axial direction with respect to the drive shaft 521. A holder plate 545 is attached to the back surface of the movable pulley piece 541, that is, the surface that does not come into contact with the V-belt 543.
The movement of the holder plate 545 with respect to the drive shaft 521 is restricted in both the rotation direction and the axial direction, and the holder plate 545 rotates integrally with the drive shaft 521. The space surrounded by the holder plate 545 and the movable pulley piece 541 forms a pocket for accommodating the roller 544 as a governor weight.

FIG. 3 shows the output shaft 62 of the transmission unit 6.
It is sectional drawing in the plane perpendicular | vertical to 0. The case of the transmission unit 6 includes a case body 612, an L case 613 and an R case 611 that cover the left and right sides thereof, and one end of an output shaft 620 is supported by the R case 611 via a bearing 632. The center of the output shaft 620 is supported by the case main body 512 via a bearing 633.

A driven sprocket 614 connected to a driving sprocket 514 of the electric unit 5 is provided at one end of the output shaft 620. At the other end of the output shaft 620, a fixed pulley piece 651 of the driven pulley 610 is provided.
The outer sleeve 653, the needle bearing 658, and the inner sleeve 659 are pivotally supported. Output shaft 6
At the end of 20, a cup-shaped clutch plate 661 is provided.

On the outer periphery of the outer sleeve 653, a movable pulley piece 652 is slidably supported on the output shaft 620. The movable pulley piece 652 is connected to the output shaft 620
Clutch disc 6 so that it can rotate integrally around
54. Between the clutch disk 654 and the movable pulley piece 652, a compression coil spring 655 that generates a repulsive force in a direction to increase the distance between them is provided.

The movable pulley piece 652 is a V-belt 543
Is transmitted to the clutch plate 661 via the shoe 662 of the clutch disk 654, and further the inner sleeve 659, the first and second planetary gear mechanisms 6
71, 681 and transmitted to the rear wheel RW via the output shaft 620.

FIG. 4 is an enlarged sectional view of the brushless motor M in the electric unit 5, and FIG. 5 is a partially broken plan view of a main part thereof.

As shown in FIG. 4, the stator core 581 is screwed to the case body 512 with screws 563. Flywheel 57 of outer rotor 570
1 is fixed to the drive shaft 521. The rotor core portion 573 of the flywheel 571 includes a flange portion 573a that is open outward at the opening thereof.
Reference numeral 90 stands vertically from the sensor substrate 591 and is positioned on a magnetic path formed in a gap between the flange portion 573a and the driving magnet 572.

In this embodiment, at least a part of the magnetic sensor 590 includes the flange portion 573a and the driving magnet 5
72 so as to fit in the space between them. The sensor substrate 591 is screwed to the plate 592 with screws 597. The plate 592 is the case body 512
Is screwed with a screw 598.

As described above, in the present embodiment, the magnetic sensor 59 is provided in the gap between the driving magnet 572 and the flange 573a which extends outward at the open end of the rotor core 573.
Since 0 is arranged, it is possible to secure a sufficient magnetic action between the outer magnetic sensor 590 and the drive magnet 572 while securing a strong magnetic action between the drive magnet 572 and the stator 580. Therefore, the rotation position can be accurately detected by the magnetic sensor 590 while the drive magnet 572 also functions as an angle detection magnet.

FIG. 6 is a block diagram showing the configuration of a drive circuit for driving the brushless motor M. The same reference numerals as those described above denote the same or equivalent parts.

The control unit 50 controls the respective excitation coils 582 of the motor M based on the high voltage (48V) supplied from the battery 10 (the first and second batteries 10a and 10b each having 24V) via the breaker 51. Supply the excitation current. The down converter 52 reduces the high voltage supplied from the battery 10 to 12 V and
7 The main switch 54 is, for example, a reed switch, and is opened and closed in a non-contact manner by bringing a magnet key 56 close to the main switch 54. The accelerator opening sensor 55 is
The opening of the accelerator grip 58 is detected.

The control unit 50 converts a high voltage supplied from the battery 10 into a predetermined DC voltage.
DC converter 501 and the DC / DC converter 5
The controller 50 is driven by the output voltage of No. 01 and determines the magnitude and timing of the exciting current supplied to each exciting coil 582 of the brushless motor M based on the outputs of the accelerator opening sensor 55 and the magnetic sensor 590.
And a driver 503 driven by the output voltage of the DC / DC converter 501 and supplying an excitation current to each excitation coil 582 of the brushless motor M in response to an instruction from the controller 502. The control unit 50 is housed at the bottom of the electric unit 5 as shown in FIG.

In the present embodiment, the high voltage (48 V) supplied from the battery 10 is in a floating state in the electric unit 5, and this high voltage does not leak outside through the case of the electric unit 5. Therefore, the driver and the occupant do not come into contact with the high voltage.

[0031]

According to the present invention, since the magnetic sensor is disposed on the magnetic path formed in the gap between the rotor core of the outer rotor and the drive magnet, a strong magnetic sensor is provided between the drive magnet and the inner stator. A sufficient magnetic action can be ensured between the outer magnetic sensor and the drive magnet while ensuring the magnetic action. Therefore, the rotation position can be accurately detected by the magnetic sensor while the drive magnet also functions as the angle detection magnet without mounting the angle detection magnet.

[Brief description of the drawings]

FIG. 1 is an overall side view of an electric motorcycle powered by a brushless motor according to the present invention.

FIG. 2 is a sectional view of an electric unit incorporating a brushless motor.

FIG. 3 is a sectional view of a transmission unit.

FIG. 4 is a sectional view of the brushless motor in the electric unit.

FIG. 5 is a partially cutaway plan view of the brushless motor.

FIG. 6 is a block diagram of a drive circuit for driving a brushless motor.

[Explanation of symbols]

Reference numeral 5: electric unit, 6: transmission unit, 520: crankshaft, 521: drive shaft, 570: outer rotor, 571
… Flywheel, 572… drive magnet, 573…
Rotor core portion, 573a flange portion, 581 stator core, 590 magnetic sensor, 591 sensor substrate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H019 AA00 BB01 BB05 BB15 BB20 BB23 CC04 CC09 DD01 EE01 FF01 5H115 PC06 PG10 PI16 PI29 PU11 PV02 PV09 RB21 UI14 UI34 UI35 5H621 BB07 GA01 GA04 HH01 JK15

Claims (2)

[Claims] 1. A brushless motor comprising: an inner stator, an outer rotor that rotates around the outer periphery thereof, and a magnetic sensor that detects a rotational position of the outer rotor, wherein the outer rotor has a cylindrical rotor core. And a plurality of drive magnets arranged on the inner peripheral surface of the rotor core portion, and a flange portion that extends outward at an open end of the rotor core portion, wherein the magnetic sensor includes the flange portion and the drive magnet. A brushless motor arranged on a magnetic path formed in a gap between the brushless motors. 2. The brushless motor according to claim 1, wherein at least a part of the magnetic sensor is disposed in a gap between the flange and a driving magnet.