JP6327474B2 - Outer rotor type variable field motor - Google Patents

Description

  The present invention uses a commutator type motor (DC motor with brush) and a rotating field type motor (permanent magnet rotor type motor) to automatically change the forward and reverse rotation directions according to the load torque. Regarding the structure of an outer rotor type brushless motor that performs field shifting (shifts), the relative position of the permanent magnet and the core of the electromagnet is shifted in the motor axial direction to change the variable overlap (overlap amount). This is an electric motor that performs magnetism (field weakening, etc.), and more specifically, it uses a cam to perform variable field, and the relative field travel (movable range) between the permanent magnet and electromagnet The present invention relates to an outer rotor type variable field motor that can increase the effect to about twice that of a single-row magnet type.

The variable field type and automatic variable field type motors are large, heavy, and expensive to manufacture because they have a complicated structure compared to general motors. For this reason, it is desirable that the mechanism for variable field be as simple, light and small as possible.
Changes over time (deterioration) also increase, so regular maintenance is required during operation.

  As is well known, there are electric motors that are used at full rated output for a long time, such as blower fans and compressors. On the other hand, there are cases where an electric motor that can freely change output characteristics from low speed to high speed and from high torque to low torque, such as an electric vehicle or an electric motorcycle, may be required. Even when it is necessary to change the power characteristics, there is a method of changing the characteristics using a mechanical transmission or the like without changing the characteristics of the motor itself. In this case, problems such as the size, weight, cost, life (change with time), and noise (vibration) of the entire power source arise. In addition, there is a method of changing the power characteristics of the motor by using a variable field using hydraulic pressure or an electric device. In this case, the mechanism and control are complicated as compared with a normal motor, and problems such as the size, weight, cost, life (time-dependent change), and maintenance (maintenance) of the entire apparatus occur.

As shown in Fig. 16, even with a DC motor of the same output, a motor with low speed rotation and high torque characteristics (first speed) ← (expressed in this way because it resembles the low gear characteristics of a manual transmission of an automobile) There are motors with different characteristics, such as motors with high speed rotation and low torque characteristics (5-speed).
In general, the former has a flat motor shape with a large diameter and the latter has a thin pencil type motor shape. Taking an electric vehicle as an example, the former is a motor characteristic that is advantageous as the power of a vehicle that climbs up a hill with heavy loads. However, without a transmission or the like, the speed does not increase even on a flat road with a light load.
The latter is a motor characteristic that is advantageous as power for a car that runs on a flat road at high speed. However, if there is no transmission or the like, the driving force of the car is insufficient when climbing a steep slope or when accelerating rapidly.

  If the amount of electric power applied to the motor is increased or decreased, a motor with any characteristics such as (1st speed) to (5th speed) shown in FIG. It seems that it can be used as an electric motor that can freely change the motor output from low to low torque. However, as long as the motor characteristics (slope of the graph) do not change, even if the amount of power applied to the motor is forcibly increased or decreased, each TN characteristic line only moves in parallel, and only the torque and rotational speed are increased or decreased independently. There is a limit. For example, using a (5-speed) motor with high-speed rotation and low-torque characteristics, if you try to obtain a high torque by forcibly increasing the amount of power (voltage) to be applied, the torque will be as if it was a (1-speed) motor. The motor does not rise, and the motor generates heat exceeding the allowable output and burns out.

There is a motor called a series winding motor that automatically reduces the induced electromotive force constant (performs field weakening) as the rotational speed of the rotor increases. The principle diagram of the motor is shown in FIG.
Usually, the field of a brushed DC motor is composed of a permanent magnet. However, as shown in FIG. 17, when the armature coil 101 and the field coil 102 are connected in series with the electromagnet field, the variable field (weak field) automatically increases as the rotational speed increases. Can be given. A motor of this system in which the armature coil 101 and the field coil 102 are connected in series is referred to as a series-winding motor. In addition to this, a split-winding motor that connects the armature coil 101 and the field coil 102 in parallel, or a multi-winding motor in which only one of the field coils is connected in series and the remaining one is connected in parallel with the armature coil; There is a motor called. In addition, there is another excitation type motor in which an armature coil and a field coil are independently connected. Here, the direct winding motor of FIG. 17 will be described.

The direct-winding motor is a so-called automatically variable field motor that automatically changes the inclination of the TN diagram shown in FIG. 16 according to the magnitude of the rotational speed. When the motor is started, a large current flows because the armature coil 101 and the field coil 102 have only winding resistance. At this time, since the field magnet has a high magnetic flux density and a large current flows through the armature coil 101, a large starting torque can be obtained. When the motor increases in rotational speed, a back electromotive voltage due to an induced electromotive voltage is generated in the armature coil 101 and acts in the opposite direction to the voltage supplied from the battery 105. As a result, the current flowing through the armature coil 101 and the field coil 102 decreases, and the magnetic flux density of the field decreases. The induced electromotive force constant is reduced, and a field weakening function is created.
Since the series-winding motor shown in FIG. 17 includes the brush 103 and the commutator 104, the change with time (wear and deterioration) is large. The direct-winding motor shown in FIG. 17 is a system that automatically weakens the field by increasing the rotation speed.

In commutator type motors (DC motors with brushes) and rotating field type motors (permanent magnet rotor type motors), the relative positions of the permanent magnets and the cores of the electromagnets are shifted in the motor axial direction so An electric motor (Patent Document 1) that performs a variable field by changing the amount of overlap) is known.
The variable field motor described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2014-50251) functions only in the forward rotation direction (when moving forward in an electric motorcycle), but automatically changes in the reverse rotation direction and regenerative braking. I do not. In addition, since the cam and the cam follower are in the vicinity of the central axis, when the displacement amount (lift amount) is large, the pressure angle becomes large, and an excessive force is applied to the cam follower (in Japanese Patent Application Laid-Open No. 2003-86260), resulting in significant wear.
According to the technique of Patent Document 1, the relative variable amount of each other (permanent magnet and electromagnet) is disclosed as small as impractical. In Patent Document 1, the variable amount is about 25% of the stack thickness of the stator core. If the amount of the variable field is increased, the displacement amount (movable range) of the rotor is increased and the length of the spring is also increased. The total length of such a motor is further increased.

JP 2014-50251 A JP 2011-50206 A JP 2008-141900 A JP 2008-216110 A JP 2010-57209 A JP 2010-51159 A JP 2008-259364 A

  The variable field motor of Patent Document 1 functions only in the forward rotation direction, but does not generate a variable field in the reverse rotation direction or regenerative braking. When used as a power source for an electric motorcycle or the like, a variable field is automatically generated in accordance with the magnitude of the load torque during forward movement, but no variable field is generated during regenerative braking. In addition, when used as a power source for an electric vehicle or the like, no variable field is generated even during reverse or regenerative braking.

Further, the variable field motor of Patent Document 1 is long because the spring and the rotor are arranged in series (in series) in the motor output shaft direction. Further, since the bearings that support the sliding motion of the rotor are arranged in series (in series) in the motor output shaft direction, there is a problem that the bearing becomes longer in the motor output shaft direction. In the diagram of Patent Document 1, the overlap margin between the rotor and the stator core can be varied from 75% to about 100%. Therefore, the variable field quantity is as small as about 25%.
In the variable field motor of Patent Document 1, when the amount of the variable field is increased, the displacement amount (movable range) of the rotor is increased and the length of the spring is also increased. Therefore, the total length of such a motor is further increased. Become.

Furthermore, the variable field motor of Patent Document 1 has an IPM (embedded magnet type) structure and uses electromagnetic steel plates laminated on both the stator and the rotor. In general, the inner rotor type has a smaller maximum torque than the outer rotor type. In order to obtain the required torque, it is necessary to increase the diameter of the motor or to increase the axial length (stack thickness) of the rotor and the stator core. As a result, the motor becomes heavy.
Furthermore, since the variable field motor of Patent Document 1 is an inner rotor type and IPM (embedded magnet type), the torque per motor weight is small. Generally, many inner rotor type motors have high-speed rotation and low torque characteristics. In order to increase torque, the inner rotor type motor needs to use a reduction gear or increase the diameters of the rotor and the stator.
As described above, in the variable field motor of Patent Document 1, since the cam and the cam follower are in the vicinity of the central axis, the circumferential length of the cam is short and the displacement amount (lift amount) cannot be increased. If the displacement amount (lift amount) is large, the pressure angle becomes large and an excessive force is applied to the cam follower (in Patent Document 1, the pin), so that the pin and the cam are significantly worn.

In addition to Patent Literature 1, Patent Literature 2, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 3, and the like have poor environmental resistance against water, muddy water, dust and the like.
In Patent Document 2, Patent Document 5, Patent Document 6, Patent Document 7, Patent Document 3, and the like, the electric wire may be bent and fatigued due to the structure that moves the stator.

  The present invention is an outer rotor type brushless motor that automatically changes (changes speed) in accordance with the magnitude of the load torque in both the forward and reverse rotation directions. The relative shift amount (movable range) of each other (permanent magnet and electromagnet) and the overall length of the motor can be shortened, and the follow-up performance of the variable field operation can be made quick. An object of the present invention is to provide an outer rotor type variable field motor.

In order to solve the above problems, the present invention provides an outer rotor type variable field motor that performs a variable field by sliding an outer rotor disposed radially outward of the stator in the motor axial direction with respect to the stator. The outer rotor is divided into an inner rotor body that slides in the motor axial direction and an outer rotor body, and the main magnet and the submagnet are axially arranged as permanent magnets disposed on the inner surface side of the inner rotor body. Are arranged in parallel with each other, the magnet characteristics of the main magnet and the sub magnet are configured in opposite directions, a cam follower is disposed on the inner rotor body, and an axial cam surface is formed on the outer rotor body, The cam follower is configured to be movable along the cam surface in accordance with a load applied to the motor shaft, and the motor shaft is configured to move the outer rotor with respect to the stator. Substantially lies in sliding movement direction.
The main magnet is disposed on the proximal end side of the inner rotor body, the sub magnet is disposed adjacent to the distal end side in the motor axial direction, and the sliding motion of the outer rotor in the motor axial direction is provided in the outer rotor body. This is done by controlling the axial position of the inner rotor body that slides in the motor axial direction by the cam surface and a resilient mechanism arranged in parallel with the motor shaft.
The size of the main magnet is larger than that of the sub-magnet in the motor axis direction, and control is performed so that the sub-magnet completely overlaps with the stator core of the stator in the motor axis direction when the motor is operating at high speed.
The size of the main magnet is larger than that of the sub-magnet in the motor axis direction, and control is performed so that the main magnet completely overlaps with the stator core of the stator in the motor axis direction when the motor is running at a low speed.

  According to the outer rotor type variable field motor according to the present invention, there are effects such that high torque can be easily generated, the thickness can be reduced, and the stator coil can be easily wound. The sliding amount of the outer rotor is only controlled by the cam surface and the spring, and the structure is simple. Cam followers and cam surfaces are used for the variable field. However, the number and size of the cam followers are more flexible than the inner rotor type, so it is easy to ensure durability. The amount of sliding of the outer rotor in the motor axial direction can be reduced. The outer rotor has a divided structure of an inner rotor body that slides in the motor axial direction and an outer rotor body, and a permanent magnet disposed on the inner surface side of the inner rotor body has a gap between the main magnet and the sub magnet in the axial direction. Since the magnet characteristics of the main magnet and the submagnet are opposite to each other, the main magnet and the submagnet move simultaneously in the motor axial direction with respect to the electromagnet core. By this movement, the action of the main magnet is increased, and the side effect of the secondary magnet is reduced at the same time, so that a larger variable field effect can be obtained as compared with the single-row magnet type. Since the main magnet and the sub magnet are arranged in opposite directions, the magnets are attracted to each other in the contact state, and the action of the magnet is reduced in the vicinity of the contact portion. Since the main magnet and the submagnet are arranged side by side with a gap in the axial direction, the main magnet and the submagnet can function independently, and the action of the magnet does not decrease.

It is a longitudinal cross-sectional view which shows the structure of the outer rotor type | mold variable field motor which changes automatically according to the magnitude | size of the load torque by embodiment of this invention applied to the outer rotor type brushless motor. It is the elements on larger scale of FIG. 1 which shows the structure of the spring for pressing the cam follower of a cam. It is a figure which shows the spring seat of FIG. It is a front view which shows the positional relationship of a magnet, a yoke, a stator, a magnetic sensor, etc. (A) is a front view which shows the external appearance of an outer rotor type variable field motor. FIG. 6B is a right side view of FIG. 5A showing the inner rotor body and the outer rotor body. FIG. 2 is a cross-sectional view showing the position of a magnet in a state where a load torque is about 25% in the outer rotor type variable field motor of FIG. 1. FIG. 2 is a cross-sectional view showing the position of a magnet in a state where the load torque is about 50% in the outer rotor type variable field motor of FIG. 1. FIG. 2 is a cross-sectional view showing the position of a magnet in a state where the load torque is about 75% in the outer rotor type variable field motor of FIG. 1. FIG. 2 is a cross-sectional view showing the position of a magnet in a state where the load torque is about 100% in the outer rotor type variable field motor of FIG. 1. It is a wave form diagram which shows the waveform of the induced electromotive voltage in a state whose load torque is about 25%. It is a wave form diagram which shows the waveform of the induced electromotive voltage of a state whose load torque is about 50%. It is a wave form diagram which shows the waveform of the induced electromotive voltage in a state whose load torque is about 75%. It is a wave form diagram which shows the waveform of the induced electromotive voltage in a state whose load torque is about 100%. FIG. 4 is a development view showing the relative positions of the inner rotor and the stator core, where (a) shows the positional relationship when the load torque is 100% or more, (b) shows the positional relationship when the load torque is about 75%, (c ) Is a diagram showing the positional relationship when the load torque is about 50%, and (d) is a diagram showing the positional relationship when the load torque is about 25%. It is a longitudinal cross-sectional view which shows the structure of the outer rotor type | mold variable field motor by other embodiment of this invention. It is a diagram showing the rotational speed and torque characteristics of a conventional motor. It is a figure which shows the principle of the direct-winding motor in which a field current also reduces automatically with the raise of the conventional rotational speed.

Embodiments of an outer rotor type variable field motor according to the present invention will be described below in detail with reference to the drawings shown in FIGS.
FIG. 1 shows the structure of an open-type outer rotor type variable field motor that automatically changes the field in accordance with the magnitude of the load torque in both the forward and reverse rotation directions applied to the brushless motor. FIG. 2 is a view showing a state in which the inner rotor main body is moved by the action of the cam and cam follower of the outer rotor type variable field motor of FIG.

  1 and 2, the outer rotor type variable field motor according to the present embodiment includes a motor body 1 and a pair of rotary bearings 2 and 3 on the inner peripheral surface side of the cylindrical portion 1a of the motor body 1. The motor shaft 4 is rotatably supported, the stator 5 is provided on the outer peripheral surface side of the cylindrical portion 1a, and is supported on one end portion of the motor shaft 4 and at a certain interval on the outer peripheral side of the stator 5. The magnet 6 is provided with an outer rotor 7 arranged so as to be movable in the axial direction.

The motor body 1 is provided with an end plate 1b on one end outer peripheral surface side of the cylindrical portion 1a, and a substrate 8 is attached to a plurality of boss portions 1c provided on the inner side of the end plate 1b via screws 9. It has been. A sliding bearing 10 is provided on the inner peripheral surface side of the cylindrical portion 1a, and a clearance is provided on the inner surface side of the sliding bearing 10 so that the rotary bearing 3 is slidable in the axial direction.
The rotary bearing 2 on the left side in the figure supports the motor shaft 4 with respect to the motor body 1 with only one degree of freedom of rotation. The right rotary bearing 3 supports the motor shaft 4 only in the radial direction. In the bearing 3, the inner ring is slidably disposed on the outer peripheral surface of the motor shaft 4, and the outer ring is assembled with a gap on the inner surface side of the sliding bearing 10. For this reason, the bearing 3 is movable in the motor axial direction in accordance with the sliding movement of the inner rotor body 72 described later. The sliding bearing 10 supports the outer ring of the right rotating bearing 3 so as to be slidable with a gap.

  Between the rotary bearing 2 and the rotary bearing 3, a plurality of coil springs 11 serving as a resilient mechanism for applying an urging force in the axial direction are spaced around the motor shaft 4 in the circumferential direction. Are arranged. As shown in FIG. 3, both ends of the coil spring 11 are engaged with a pair of disk-shaped spring seats 12 arranged on the inner surface of the cylindrical portion 1a. The pair of spring seats 12 are arranged to face each other between the rotary bearing 2 and the rotary bearing 3 and support both ends of the coil springs 11 arranged at regular intervals in the circumferential direction. The spring seat 12 arranged on the rotary bearing 3 side is arranged to be slidable in the axial direction along with the sliding of the rotary bearing 3.

  The stator 5 is composed of a stator core 51 in which steel plates are laminated, and a stator coil 53 wound around an insulator 52 assembled to the stator core 51, and is assembled to the outer peripheral surface side of the cylindrical portion 1a via a mounting screw 54. ing. Both ends of the stator coil 53 are connected to the circuit of the substrate 8, and driving power and control signals are sent by an electric wire 13 composed of an external power line and a control line connected to this circuit. As shown in FIG. 4, the stator core 51 has nine pole teeth 51a formed at every angle of 40 degrees, and the stator coil 53 is configured by winding a winding 53a around each pole tooth 51a. An insulator 52 formed of an insulating material is assembled in advance on the stator core 51 to keep the insulation between the stator core 51 and the stator coil 53.

The outer rotor 7 includes a bottomed cylindrical outer rotor body 71 having a central portion attached to a base end portion of the motor shaft 4, and slides in the axial direction of the motor shaft 4 inside the outer rotor body 71. A bottomed cylindrical inner rotor body 72 that is movably arranged is divided into two parts. As shown in FIG. 5B, the outer rotor main body 71 is curved so as to form a concave cam surface 73a having an inclined surface in the axial direction along the circumferential direction. In the illustrated example, three cams 73 are formed at predetermined intervals in the circumferential direction. The cam surface 73a of the cam 73 is formed in a substantially V shape having a valley in the motor shaft direction.
The cam surface 73a of the cam 73 forms an inclined portion 73c that gradually rises on both sides from the lowest point 73A of the valley bottom 73b formed in a substantially V shape, and faces in the uppermost point 73B of the upper portion 73d of the valley. The stopper portion 73e curved so as to draw a substantially semicircle is formed.

  On the other hand, a radial cam follower shaft 74 is mounted at each apex position on the outer peripheral cylindrical portion 72a of the inner rotor body 72 so as to form an equilateral triangle, and the cam follower shaft 74 is attached to the cam surface 73a. Cam followers 75 that roll and move along are respectively mounted. A central base end portion 72b of the inner rotor body 72 is attached to a ring-shaped rotary slide bearing 76. The rotary slide bearing 76 can be rotated and slid by inserting the motor shaft 4 on an axis. It is supported by. As shown in FIG. 1, the rotary slide bearing 76 is in sliding contact with the right side surface of the inner ring of the right rotary bearing 3 and is in sliding contact with the motor shaft 4.

14, the a magnetic sensor for a rotating position detection which is disposed between the stator pole teeth 51a each other of the stator 5, the rotational position detecting magnetic sensor 14, the main magnet ring ₆₁ of the inner rotor body 72 with respect to the stator 5 The position of the main magnet 6 </ b> A provided in the rotation direction is detected. The position of the inner rotor body 72 in the motor shaft direction is not detected. As shown in FIGS. 1 and 2, even if the inner rotor body 72 slides in the motor axial direction, the position of the inner rotor body 72 (main magnet 6A) in the rotational direction relative to the stator 5 can be detected in the entire region. Reference numeral 15 denotes a vent for releasing the pressure fluctuation caused by the change in volume of the air chamber between the rotary bearings 2 and 3 to the atmosphere and mitigating it.

  The outer peripheral cylindrical portion 72 a of the inner rotor main body 72 is formed to be longer in the axial direction than the outer peripheral cylindrical portion 71 a of the outer rotor main body 71, and the outer peripheral cylindrical portion 72 a of the inner rotor main body 72 is formed. On the inner surface side, a magnet 6 is mounted in which a main magnet 6A and a submagnet 6B are arranged in the axial direction with a gap g therebetween. The main magnet 6A and the sub magnet 6B are configured so that their magnet characteristics are opposite to each other.

  The main magnet 6A has a permanent magnet 61A in which the polarity of the N pole is on the inner peripheral side and the polarity of the S pole on the outer peripheral side, the polarity of the S pole on the inner peripheral side, and the polarity of the N pole on the outer peripheral side. The arranged permanent magnets 62A are alternately arranged in the circumferential direction to form six sets of poles. On the other hand, the secondary magnet 6B has a permanent magnet 61B in which the polarity of the N pole is on the inner peripheral side and the polarity of the S pole on the outer peripheral side, and the polarity of the S pole is on the inner peripheral side and the polarity of the N pole is the outer peripheral side. Six pairs of poles are formed by alternately arranging the permanent magnets 62B arranged on the side in the circumferential direction. In FIG. 4, the reference numerals (61B) and (62B) indicate the positions of the permanent magnets 61B and the permanent magnets 62B of the submagnet 6B that are shifted by 60 degrees in the circumferential direction and changed in polarity with the main magnet 6A. It is shown.

  The permanent magnet 61A and the permanent magnet 61B, and the permanent magnet 62A and the permanent magnet 62B are assembled to the inner surface side of the outer peripheral cylindrical portion 72a of the inner rotor main body 72 via a cylindrical main yoke 63A and sub yoke 63B. ing. The yokes 63 </ b> A and 63 </ b> B form a magnetic path and are attached to the outer peripheral cylindrical portion 72 a of the inner rotor main body 72 via a yoke set screw 64.

The main magnet 6A and subsidiary magnets 6B, as shown in FIG. 4, the main yoke is installed inside the (magnetic path) 63A and auxiliary yoke 63B, the main magnet ring ₆₁ and the sub magnet ring 6 ₂ are formed They are each magnetized in the radial direction. The main yoke 63A and the sub yoke 63B are installed inside the outer peripheral cylindrical portion 72a of the inner rotor main body 72. Since the surface magnet type outer rotor type magnet is less likely to fall off due to centrifugal force or the like than the inner rotor type magnet, a drop preventing ring is often unnecessary. Therefore, the main magnet 6A and the sub magnet 6B can be closer to the stator core 51 in the radial direction. For this reason, the maximum torque to be generated also increases. The ratio of the main magnet ring ₆₁ and the sub magnet ring 6 ₂ thickness, sub-magnet ring 6 ₂ thickness (axial length) = 3/8 × main magnet ring ₆₁ of a thickness (axial length ).

Next, the relationship among the inner rotor body 72, the cam 73, and the cam follower 75 will be described.
Inside the inner rotor body 72, a main magnet ring ₆₁ and the sub magnet ring 6 _2, placed at a magnetic gap g in the axial direction of the motor, to prevent the effect of the magnet is decreased. Three cam followers 75 are installed on the outer periphery of the inner rotor body 72 at regular intervals in the circumferential direction. As shown in FIGS. 1 and 2, the inner rotor main body 72 is pushed in the vicinity of the center by the coil spring 11 and the spring seat 12 in the right direction in the figure. As described above, the three cams 73 and the cam follower 75 are arranged in an equilateral triangle when the motor is viewed from the front.

  As a result, the inner rotor body 72 is supported by the outer rotor body 71 (three cam surfaces) so that the tripod stands stably, and stably rotates and slides relative to each other. Positioning of the inner rotor body 72 in the radial direction is performed by the rotary slide bearing 3 fitted with a gap on the motor shaft 4 as shown in FIGS.

  The position of the inner rotor body 72 in the rotational direction relative to the outer rotor body 71 changes depending on the magnitude of the load torque received by the motor shaft 4 (integrated with the outer rotor body 71). At this time, the position of the inner rotor body 72 in the motor axial direction also changes with respect to the outer rotor body 71 by the action of the cam 73 and the cam follower 75 provided on the outer rotor body 71 and the inner rotor body 72.

  In the example of FIG. 1, the inner rotor body 72 is closest to the outer rotor body 71 when the magnitude of the load torque received by the motor shaft 4 is about 25% or less of the maximum torque. 6 to 9 also show the position of the magnet 6 relative to the stator core 51 when the load torque receives a torque of about 25% or less to 100% or more. 6 to 9 show four stages, the inner rotor body 72 slides steplessly in the axial direction of the motor depending on the magnitude of the load torque applied to the motor shaft 4, and the overlapping amount of the magnet 6 and the stator core 51 is not limited. Changes steplessly.

  FIG. 6 shows the position of the magnet 6 in a state where the load torque is about 25%. The tip of the secondary magnet 6B in the axial direction moves to a position substantially coincident with the tip of the stator core 51, and the base of the main magnet 6A is shown. The end side is moved from the base end of the stator core 51 to the end position of the stator coil 53.

  FIG. 7 shows the position of the magnet in a state where the load torque is about 50%. The tip of the secondary magnet 6B in the axial direction is substantially coincident with the intermediate position of the stator coil 53 beyond the tip of the stator core 51. The base end side of the main magnet 6 </ b> A is moved away from the base end of the stator core 51 to a position substantially coincident with the intermediate position of the stator coil 53 on the opposite side.

  FIG. 8 shows the position of the magnet in a state where the load torque is about 75%, and the position where the tip of the secondary magnet 6B in the axial direction substantially coincides with the vicinity of the tip of the stator coil 53 ahead of the tip of the stator core 51. , The distal end of the main magnet 6A moves closer to the distal end of the stator core 51, and the proximal end portion side of the main magnet 6A slightly deviates from the proximal end of the stator core 51 and slightly coincides with the stator coil 53 on the opposite side. Moved to position.

  FIG. 9 shows the position of the magnet in a state where the load torque is about 100%, and the tip of the secondary magnet 6B in the axial direction is substantially coincident with the tip of the stator coil 53 beyond the tip of the stator core 51. The leading end of the main magnet 6 </ b> A moves to a position that substantially matches the leading end of the stator core 51, and the base end side of the main magnet 6 </ b> A moves to a position that substantially matches the base end of the stator core 51.

The induced electromotive voltage at this time is shown in FIGS. In each drawing, the alternate long and short dash line indicates the waveform of the main magnet 6A, the broken line indicates the waveform of the submagnet 6B, and the solid line indicates the combined waveform of the main magnet 6A and the submagnet 6B. FIG. 10 shows an induced electromotive voltage waveform in a state where the load torque is about 25%. FIG. 11 shows an induced electromotive voltage waveform in a state where the load torque is about 50%. FIG. 12 shows an induced electromotive voltage waveform in a state where the load torque is about 75%. FIG. 13 shows an induced electromotive voltage waveform in a state where the load torque is about 100%.
This shows that the motor is automatically variable fielded.

The operation of the coil spring 11 at this time will be described.
As described above, the coil spring 11 presses the cam follower 75 installed on the outer periphery of the inner rotor body 72 against the cam 73 installed on the outer periphery of the outer rotor body 71. As shown in FIG. 1, the force of the coil spring 11 includes the coil spring 11, the right spring seat 12, the inner ring of the right rotating bearing 3, the rotating sliding bearing 76, the inner rotor body 72, the cam follower 75, the cam 73, and the outer rotor body 71. The power is transmitted to the motor shaft 4, the right shaft retaining ring 22 of the left rotary bearing 2, and the left spring seat 12, and the force returns to the coil spring 11 (the force is closed). Thus, since the force of the coil spring 11 does not act as a thrust force on the rotary bearings 2 and 3 that support the rotation of the motor shaft 4, the force of the coil spring 11 does not directly become the rotational load resistance of the motor shaft 4.

  As shown in FIG. 3, a plurality of coil springs 11 (six examples are shown in FIG. 3) are arranged around the motor shaft 4. By dividing the coil spring 11 into a plurality of pieces, the spring load can be shared and the wire diameter of the coil spring 11 can be reduced. As shown in FIG. 1, even when the contact length is small, the number of turns of each coil spring 11 can be increased, so that the spring constant can be set in a wider range. Moreover, the utilization efficiency of the space in which the coil spring 11 is installed also increases. The coil spring 11 is supported by counterbore holes provided on the spring seat 12 at both ends. The force of the coil spring 11 is collected by the spring seat 12, and can be transmitted to the next part near the motor shaft 4 by a projection (seat) provided near the motor shaft 4.

  The relationship between the cam 73 and the cam follower 75 will be described with reference to FIGS. 5B and 14A, 14B, 14C, and 12D. The cam 73 is formed on the outer periphery of the outer rotor body 71 as viewed from the front of the motor. Are arranged on the outer peripheral portion of the inner rotor body 72 so as to be equilateral triangles. The right side of FIGS. 1 and 14 (d) represents a time when the magnitude of the load torque received by the motor shaft 4 is about 25% or less of the maximum torque. At this position, the outer rotor body 71 and the inner rotor body 72 are closest to each other. At the lowest point 73A, the radius of the contact surface of the cam 73 is slightly increased with respect to the radius of the roller of the cam follower 75 in order to reduce the impact during the movement of the cam 73 and the cam follower 75.

  2 and 14 (a) show the case where the magnitude of the load torque received by the motor shaft 4 receives 100% or more of the maximum torque. Also at the uppermost point 73B, the radius of the contact surface of the cam 73 is slightly increased. As shown in FIGS. 5B and 14A, the uppermost point 73B is provided with a stopper 73e. A cam surface 73a connecting the lowest point 73A and the highest point 73B is connected by a curved surface. FIG. 14B shows a time when the load torque is about 75% of the maximum torque. FIG. 14C shows the case where the load torque is about 50% of the maximum torque.

Next, the operation of the outer rotor type variable field motor according to the embodiment of the present invention will be described.
As shown in FIG. 1, the outer rotor 7 is rotated by a rotating magnetic field generated between the stator 5 and the outer rotor 7, and the rotation of the outer rotor body 71 directly connected to the motor shaft 4 is transmitted to the motor shaft 4. A load assembled to the shaft 4 is driven. If the load is an automobile, the rotation of the motor shaft 4 is transmitted to the wheels, and traveling is started. In the outer rotor 7, the rotation of the inner rotor body 72 is transmitted to the outer rotor body 71 via the cam 73 and the cam follower 75, and the motor shaft 4 is driven.

  When a load is applied to the motor shaft 4, a displacement due to rotation occurs between the outer rotor body 71 directly connected to the motor shaft 4 and the inner rotor body 72 attached to the rotary slide bearing 76, and the inner rotor The cam follower 75 of the main body 72 rotates along the cam surface 73a of the cam 73 of the outer rotor main body 71 to move the inner rotor main body 72 in the axial direction. The inner rotor body 72 sequentially moves from FIG. 6 to FIG. 9 against the urging force of the coil spring 11.

  In a state where the load torque is about 25%, as shown in FIG. 6, the tip end of the secondary magnet 6B in the axial direction moves to a position substantially coincident with the tip end of the stator core 51, and the base end side of the main magnet 6A is the stator core 51. And move to the end position of the stator coil 53. A waveform of the induced electromotive voltage at this time is shown by a solid line in FIG.

  Next, in a state where the load torque is about 50%, as shown in FIG. 7, the axial tip of the secondary magnet 6 </ b> B moves to a position that substantially coincides with the intermediate position of the stator coil 53 beyond the tip of the stator core 51. The base end side of the main magnet 6 </ b> A moves away from the base end of the stator core 51 and moves to a position that substantially coincides with the intermediate position of the stator coil 53 on the opposite side. A waveform of the induced electromotive voltage at this time is shown by a solid line in FIG.

  In the state where the load torque is about 75%, as shown in FIG. 8, the axial tip of the secondary magnet 6 </ b> B moves to a position that substantially coincides with the vicinity of the tip of the stator coil 53 ahead of the tip of the stator core 51. The tip of the main magnet 6A moves near the tip of the stator core 51, and the base end side of the main magnet 6A moves slightly away from the base end of the stator core 51 to a position that slightly matches the stator coil 53 on the opposite side. To do. A waveform of the induced electromotive voltage at this time is shown by a solid line in FIG.

In the state where the load torque is about 100%, as shown in FIG. 9, the axial tip of the secondary magnet 6 </ b> B moves to a position that substantially coincides with the tip position of the stator coil 53 ahead of the tip of the stator core 51. The front end of the main magnet 6 </ b> A moves to a position that substantially matches the front end of the stator core 51, and the base end side of the main magnet 6 </ b> A moves to a position that substantially matches the base end of the stator core 51.
A waveform of the induced electromotive voltage at this time is shown by a solid line in FIG.

In this way, as shown in FIGS. 6 to 9, the coil spring 11, the cam 73, and the cam follower 75 change the relative overlap margin of the stator core 51, the main magnet 6 </ b> A, and the magnet 6 made of the submagnet 6 </ b> B to thereby induce induction. The electromotive force constant (torque constant) is changed, and the motor characteristics (inclination of the TN line in FIG. 16) are changed.
In this way, the outer rotor type brushless motor that automatically changes (changes speed) in accordance with the magnitude of the load torque in the forward and reverse rotation directions by the coil spring 11, the cam 73, and the cam follower 75 shown in FIG. Functions and structures can be formed.
The main magnet ring ₆₁ and the sub magnet ring 6 _2, with respect to the stator core 51, in the axial direction of the motor, move simultaneously. This movement increases the action of the main motor of the magnet ring _61, by the side effects as a generator of auxiliary magnet ring 6 ₂ decreases, larger and more as compared to the magnet of one row (approximately 2 fold) A variable field effect is obtained. The main magnet ring ₆₁ and the sub magnet ring 6 _2, the polarity of the magnets are arranged in the opposite direction, is in contact in the vicinity of the contact portion adsorbed on the interaction of the magnet is decreased. Since there is provided a magnetic gap g between the main magnet ring ₆₁ and the sub magnet ring 6 _2, the core of the electromagnet, be made to function independently of the main magnet ring ₆₁ and the sub magnet ring 6 ₂ It is possible to prevent a decrease in the action of the magnet. The main magnet ring ₆₁ and the sub magnet ring 6 _2, since the non-magnetic steel rotor is fixed with screws or the like, not to lose the effect of the magnet magnetically coupled through the housing and the yoke. The main magnet ring ₆₁ acts independently of the core of the electromagnet, the sub-magnet ring 6 ₂ acts independently of the core of the electromagnet. Thus, when the main magnet ring ₆₁ and the core of the electromagnet acts as a motor, the core of the secondary magnet ring 6 ₂ and the electromagnet can function as a generator.

During regenerative braking, the variable field is automatically generated according to the magnitude of the load torque (here, according to the magnitude of the braking torque). Even when the motor rotates at a low speed, as shown in FIGS. 6 to 9, the variable field is automatically generated and the induced electromotive force constant is changed from FIG. 10 to FIG. Since it becomes large as shown, the effect of regenerative braking becomes larger. Therefore, the regenerative power can be collected more effectively.
The thrust load by the coil spring 11 is not applied to the rotary bearings 2 and 3 that support the motor shaft 4. Thus, there is no increase in rotational resistance due to the addition of the variable field function.

  Since the inertia (moment of inertia) of the inner rotor body 72 including the main magnet 6A and the submagnet 6B is small, the variable field function at the time of start-up is quick. As a result, when the motor is started, even if the load torque applied to the motor shaft 4 is large and the rise of the rotation of the outer rotor body 71 is delayed, the variable field effect appears more quickly, and the torque constant increases more rapidly. The rise of the axis 4 becomes faster.

As shown in FIG. 1, an open-type outer rotor brushless motor that automatically changes the field torque according to the magnitude of the load torque in both the forward and reverse rotation directions has an outer rotor 7 and a stator 5 with an open-type structure. Therefore, the effect of air cooling is high.
Since only the inner rotor body 72 slides in the motor axial direction inside the motor, the total length of the motor does not change.

By covering or molding the stator core 51, the substrate 8, the magnet 6 and the yoke (magnetic path) with a resin, environmental resistance such as drip-proofing is improved.
By providing the inner rotor body 72 including the outer rotor body 71, the main magnet 6A, and the submagnet 6B, a so-called variable field function is realized by a method of changing the overlap margin (in the motor axis direction) of the outer rotor 7 and the stator 5. However, neither the stator 5 nor the outer rotor main body 71 is moved (in the motor axis direction).
Functional components such as the motor shaft 4, the coil spring 11, the sliding bearing 10, the stator core 51, the magnetic sensor 14 for detecting the rotational position of the inner rotor body 72, the magnet 6, the yoke (magnetic path) 63, the cam follower 75, the cam 73, and the like in the radial direction. The outer rotor brushless motor structure that is flat and has high torque is realized by overlapping the arrangement.

FIG. 15 shows a sealed outer rotor type variable field motor according to another embodiment of the present invention. The same parts as those in FIG. 1 and FIG. Will be omitted.
The upper half of FIG. 15 represents the time when the magnitude of the load torque received by the same motor shaft 4 as in FIG. 1 is about 25% or less of the maximum torque. The lower half of FIG. 15 represents the time when the magnitude of the load torque received by the same motor shaft 4 as in FIG. 2 is 100% or more.
The motor main body 1 includes a motor main body front portion 16 and a motor main body rear portion 17, and a sealed motor is configured by fastening the outer peripheral cylindrical portion 16 a and the outer peripheral cylindrical portion 17 a provided on the outer peripheral portion with screws 18. . The motor main body rear 17, the boss portion 17b is provided at the center, which creates a sealed structure by placing the rotational bearing 3 ₂ in the boss portion 17b.
As described above, the sealed motor has the same basic performance and function as the open motor shown in FIG. 1, and the motor body 1 has a sealed structure. Is expensive.

According to the outer rotor type variable field motor according to the above embodiment, the variable field is automatically variable according to the magnitude of the load torque in both the forward and reverse rotation directions. High torque can be output at startup even during reverse (reverse rotation).
Also during regenerative braking, variable field is automatically generated according to the magnitude of the load torque (in this case, braking torque). For this reason, regenerative electric power can be more effectively collected even in a state of low speed rotation.

In addition, since the outer rotor body 71, the inner rotor body 72 provided with the main magnet 6A and the submagnet 6B, the stator 5, the spring 11, and the motor shaft 4 are arranged in the radial direction, the thickness portion is formed in a flat shape. High torque is generated at startup. Moreover, high speed rotation is possible by variable field.
Furthermore, since the open motor has a high air cooling effect and is light, the output per weight can be increased.

On the other hand, since the sealed motor has high environmental resistance, it can be used in places where use conditions are severe, such as an electric vehicle and an electric motorcycle.
Further, since only the inner rotor body 72 having the main magnet 6A and the sub magnet 6B slides in the motor axial direction inside the motor during the variable field, the total length of the motor is also increased during the variable field. It does not change. Little change in the center of gravity of the motor.

Further, since the stator coil 53 does not slide (movable) in the motor axial direction during the variable field, the electric wire 13 does not bend and fatigue.
Furthermore, the force of the spring 11 for creating a function of automatically changing the field according to the magnitude of the load torque is closed in the rotor 7. That is, the force of the spring 11 does not act as a thrust force on the rotary bearings 2 and 3 that support the rotation of the motor shaft 4. Therefore, since the force of the spring 11 does not become a direct rotational load resistance of the motor shaft 4, it does not cause a loss of the motor.

  Although it is a high-performance brushless motor that automatically changes the field according to the magnitude of the load torque in both the forward and reverse rotation directions, it is small (flat), lightweight, low cost, high torque, high rotation, in a wide rotation range A highly efficient motor can be made. Also, when using as a regenerative brake, if a large amount of regenerative energy is extracted even at low speed rotation, a variable field is automatically generated according to the magnitude of the load torque (in this case, the braking torque) (induction The regenerative energy can be recovered more (regenerative braking works well).

The present invention can be downsized (flattened) by arranging functional parts such as a rotating shaft, a spring, a bearing, a stator, a rotor, a cam, and a cam follower in a radial direction. In addition, in order to prevent tilting and shaking during the sliding movement of the rotor, it is created by bearings for both rotation and sliding, three sets of cams and cam followers installed on the outer periphery of the rotor, and a spring that presses them. In this way, it is possible to prevent tilting and shaking so that the tripod placed on the floor is stabilized by gravity.
The outer rotor type has a SPM (surface magnet type) structure in which the magnet is directly installed (adhered) inside the yoke (magnetic path), and the centrifugal force applied to the magnet is directed to the outside (yoke side). There is no falling off of the magnet due to force. In that regard, the SPM (surface magnet type) inner rotor type requires a drop prevention ring outside the magnet.

  The original form of the present invention is an outer rotor type brushless motor. In general, the outer rotor type has a larger rotor diameter than the inner rotor type, and therefore has a relatively high torque and low speed rotation. Therefore, the torque per weight of the motor is large. Applications can be expected in fields that require high torque, such as in-wheel motors and direct drive motors.

  As in the present invention, when the overlap between the rotor and the stator core can be varied from about 25% to about 100% (variable field quantity is 4 times), the diagram of Japanese Patent Application Laid-Open No. 2014-50251 is further elongated in the axial direction. It is.

  Note that the present invention is not limited to the above-described embodiment, and the outer rotor type variable field motor is not limited to an electric vehicle or an electric motorcycle. It can also be used for loads. In the above-described embodiment, the case where three sets of cams 73 and cam followers 75 are used has been described, but three or more sets of cams 73 and cam followers 75 such as four sets, five sets, and six sets may be used. Corresponding to this, the rotational position detecting magnetic sensors 14 of the inner rotor main body 72 can also be used in four sets, five sets, six sets, and the like. In addition, it goes without saying that the present invention can be appropriately modified and implemented within a range that does not change the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Motor body 1a Cylindrical part 2 Rotating bearing 3 Rotating bearing 4 Motor shaft 5 Stator 6 Magnet 6A Main magnet 6B Sub magnet 6 ₁ Main magnet ring 6 ₂ Sub magnet ring 7 Outer rotor 8 Substrate 9 Screw 10 Sliding bearing 11 Coil spring 12 Spring seat DESCRIPTION OF SYMBOLS 13 Electric wire 14 Magnetic sensor for rotational position detection 15 Air vent 16 Motor main body front part 17 Motor main body rear part 18 Screw 53 Stator coil 61A, 61B Permanent magnet 62A, 62B Permanent magnet 63 Yoke (magnetic path)
63A Main yoke 63B Sub yoke 71 Outer rotor main body 72 Inner rotor main body 73 Cam 74 Cam follower shaft 75 Cam follower 76 Rotary sliding bearing

Claims (4)

In an outer rotor type variable field motor that performs a variable field by sliding an outer rotor arranged radially outside the stator with respect to the stator in the motor axial direction,
The outer rotor has a split structure of an inner rotor body that slides in the motor axial direction and an outer rotor body,
As a permanent magnet disposed on the inner surface side of the inner rotor body, the main magnet and the sub magnet are arranged side by side with a gap in the axial direction, and the magnet characteristics of the main magnet and the sub magnet are configured to be opposite to each other.
A cam follower is disposed on the inner rotor body, an axial cam surface is formed on the outer rotor body, and the cam follower is configured to be movable along the cam surface in accordance with a load applied to the motor shaft. The outer rotor type variable field motor is characterized by causing the stator to slide substantially in the motor axial direction with respect to the stator.   The main magnet is disposed on the proximal end side of the inner rotor body, the sub magnet is disposed adjacent to the distal end side in the motor axial direction, and the sliding motion of the outer rotor in the motor axial direction is provided in the outer rotor body. 2. The outer rotor type variable field according to claim 1, wherein an axial position of the inner rotor body that slides in the motor axial direction is controlled by a cam surface and a resilient mechanism disposed in parallel with the motor shaft. Magnetic motor.   The outer magnet according to claim 1 or 2, wherein the main magnet is larger in the motor axial direction than the sub magnet, and the secondary magnet completely overlaps with the stator core of the stator in the motor axial direction when the motor is operating at high speed. Rotor type variable field motor.   The outer magnet according to claim 1 or 2, wherein the main magnet is larger than the sub magnet in the motor axial direction, and the main magnet completely overlaps with the stator core of the stator in the motor axial direction when the motor is at a low speed. Rotor type variable field motor.

Images