JP2001045729A - Motor integrated with wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor integrated with wheels for making a man-powered vehicle, such as a wheelchair, which is easy to carry and moreover satisfactory in quality of side. SOLUTION: With respect to this motor 10 integrated with wheels, since the motor is composed of a fixed disk 12 as a stator and wheel disks 14 as a rotor, there is not need for a space for installing the motor. Since the wheel disks 14 constitute wheels, an area for installing rotor magnets 24 required for the direct drive of the wheels is ensured, and a speed reducer is unnecessary. For this reason, the weight of the entire wheelchair can be reduced, and its width in folding can be reduced as well. Therefore, a wheelchair easy to carry can be manufactured by using the motor 10 as a drive wheel. In addition, since the rotor magnets 24 opposed to each other between the wheel disks 14 are different in magnetic properties, the magnetic force produced in the fixed wheel 12 is extremely low, so that cogging torque is not produced, and the riding quality of the wheelchair can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel-integrated motor in which a motor and wheels are integrally formed.

[0002]

2. Description of the Related Art Conventionally, it is mounted on a manually driven vehicle such as a wheelchair or a bicycle that is driven and driven by human power, and is operated when a strong driving force is required, such as on an uphill, and the driving wheel of a manually driven vehicle. There is an assist motor that applies a driving force to the vehicle and assists the driving force required to climb an uphill.

The assist motor 100 includes, for example, a rotor 11 formed in a cylindrical shape as shown in FIG.
0 and a so-called radial gap type brushless motor (hereinafter referred to as a "radial motor") composed of a stator 120 formed in a cylindrical shape coaxial with the rotation axis of the rotor 110 so as to cover the rotor 110. Have been.
The assist motor 100 is attached to, for example, a lower portion of a wheelchair seat, a rear portion of a backrest, or the like.

Since the assist motor is mounted on a wheelchair or the like that basically relies on human power, the size of the assist motor is reduced by reducing the size.
If the motor diameter of the assist motor is reduced along with the downsizing, sufficient driving force cannot be obtained, so a speed reducer is installed in the transmission system between the motor and the driving wheels that transmits the driving force of the motor to the driving wheels. , Supplementing the driving force.

[0005]

The above-mentioned wheelchair is structurally required to be folded so that it can be carried on a train or a car.

However, in order to increase the driving force, the assist motor including the radial motor increases the width in the rotation axis direction (width in the direction perpendicular to the plane of FIG. The radius of the child 120 must be increased, while the smaller the driving force, the larger the speed reducer must be used due to the gear ratio. Therefore, in a wheelchair provided with a conventional assist motor, it has been difficult to reduce the overall volume and weight of the assist motor and the speed reducer in total, even if a downsized assist motor is used. For this reason, conventional wheelchairs cannot be reduced in folding width and weight cannot be reduced.
There was a problem that it was inconvenient to carry.

On the other hand, it is generally known that cogging is likely to occur in a radial motor because the stator has an iron core.

For example, in the radial motor shown in FIG. 3, the stator core 122 forming the stator 120 forms a magnetic circuit, and the magnetic flux emitted from the N-pole rotor magnet 112N provided on the drum surface of the rotor 110 is Mostly,
S-pole rotor magnet 112S passing through stator core 122
This is because, as a result, N or S polarity is generated at a point (for example, point α) and a point (for example, point β) where magnetic flux enters the stator core 122. Then, the generated polarity causes the stator core 122 and the rotor magnet 112 to attract or repel each other, thereby forming a stable point at which the rotor position where the attractive force and the repulsive force are balanced is stabilized. For example, in the radial motor illustrated in FIG. 3, the rotor has 16 rotor magnets and the field coil has 12 salient poles, so that the stable points are formed at 48 locations, which are the least common multiple of 16 and 12. You.

In other words, in the radial motor having such a stable point, the rotor 110 stopped at the stable point
When the rotor 110 is to be moved, the rotor 110 repels the force to be moved and generates a force to return to the original position (stable point). A force is generated that attempts to advance to the point. Therefore, the rotor 11
0 rotates so as to move discretely at a stable point until the rotation is stabilized by the inertial force, and so-called cogging occurs.

Therefore, a wheelchair provided with this radial motor as an assist motor has a problem that the ride comfort is poor, and even if the power is turned off, the load becomes heavy due to the cogging torque caused by the magnet. was there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wheel-integrated motor for making a human-powered vehicle such as a wheelchair which is easy to carry, has good riding comfort, and can be pushed lightly.

[0012]

According to a first aspect of the present invention, an axle fixed to a vehicle body is rotatably mounted on a vehicle, and a center axis of the vehicle is set on a center axis of the axle. A wheel having a pair of wheel discs disposed close to each other, and a fixed disc disposed in a close space formed between the wheel discs and fixed to the axle;
A field coil provided on a plate surface of the fixed disk; and a rotor magnet provided on a plate surface of the wheel disk facing the field coil, wherein the wheel operates as a rotor and the fixed disk operates as a stator. This is a wheel-integrated motor.

The wheel-integrated motor according to claim 1 is
When electric power is supplied to the field coil provided on the fixed disk, a rotor magnet provided on the wheel disk receives a driving force, and as a result, the wheel disk rotates. That is, in the wheel-integrated motor according to the first aspect, the fixed disk constitutes the motor as the stator, the wheel disk constitutes the rotor, and the wheel disk constitutes the wheels. Therefore, in the wheel-integrated motor according to the first aspect, since the motor and the wheel are integrally formed, an external mounting space for installing the motor is unnecessary.

Further, in the wheel-integrated motor according to the first aspect, since the wheel disk constitutes the wheel, a driving force for directly driving the wheel is obtained by using a plane parallel to the radial direction of the wheel. Thus, an area for installing the rotor magnet required for the above can be secured. Therefore, the wheel-integrated motor according to the first aspect does not require a device corresponding to a speed reducer.

Therefore, when the wheel-integrated motor according to the first aspect is used as a driving wheel of a human-powered vehicle such as a wheelchair, a speed reducer can be omitted, so that the weight of the entire human-powered vehicle can be reduced. When mounted on a human-powered traveling vehicle that needs to be folded and transported, such as a wheelchair, a mounting space for installing a motor and a speed reducer is unnecessary, so that the folding width can be reduced.

Therefore, when the wheel-integrated motor according to the first aspect is used as a drive wheel of a human-powered vehicle, a portable human-powered vehicle can be provided.

Note that the human-powered vehicles include all vehicles that run manually, such as bicycles, in addition to wheelchairs.

Further, since the wheel-integrated motor according to the first aspect has a so-called coreless structure in which the stator does not have a ferromagnetic material such as an iron core, no cogging torque is generated even when the motor is rotated in a non-excited state. Therefore, when the wheel-integrated motor according to claim 1 is used in a human-powered vehicle such as a wheelchair,
Riding comfort is better than that of a conventional man-powered vehicle, and a load can be lightly applied because a load due to cogging torque is not applied.

Next, a wheel-integrated motor according to a second aspect is characterized in that, in the wheel-integrated motor according to the first aspect, the rotor magnet is a magnet using a material made of a rare earth element.

In the wheel-integrated motor according to the second aspect, since a magnet made of a material made of a rare earth element which generates a stronger magnetic force than ferrite or the like is used, compared with a conventional rotor magnet made of ferrite or the like, In order to obtain the required magnetic force, the size and weight of the rotor magnet itself can be reduced in thickness and weight.

Therefore, when the wheel-integrated motor according to claim 2 is applied to a wheelchair, the folding width of the wheelchair can be further reduced, and the weight of a human-powered vehicle including the wheelchair to which the wheel-integrated motor is applied. Therefore, it is possible to provide a man-powered vehicle that is easy to carry.

According to a third aspect of the present invention, there is provided a wheel-integrated motor according to any one of the first and second aspects, wherein the rotor magnets having different polarities are respectively provided on the pair of wheel discs. The pair of wheel discs are alternately arranged along the circumferential direction of the wheel discs, and the pair of wheel discs are positioned so that the opposite polarity of the rotor magnets is different between the two wheel discs.

It is necessary that the magnetic flux emanating from the rotor magnet pass vertically through the coil as much as possible. In the wheel-integrated motor according to the third aspect, as shown in FIG. 4, since the polarity of the rotor magnets facing each other is different between the wheel discs, the magnetic flux generated from the rotor magnet attached to one of the wheel discs is reduced. Most enters the rotor magnet mounted on the other side of the wheel disc.

If there is no wheel disc at the opposing position, the magnetic flux leaking to the adjacent pole without passing through the coil increases near the boundary of the portion where the magnetism of the same wheel disc is different, so that it does not work effectively as generated torque. Efficiency gets worse.

Further, since the two pairs of wheel discs rotate together, no change in magnetic flux occurs between the two rotor magnets. Therefore, even if the motor rotates at a high speed, no eddy current is generated and the loss can be reduced.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment to which the present invention is applied will be described below.

FIG. 1 is a partially transparent perspective view of a wheelchair to which the wheel-integrated motor of this embodiment is applied.

As shown in FIG. 1, the wheelchair 1 mainly includes a body frame 3 including left and right side frames 30 and a seat supporting frame 32 for connecting the side frames 30 so as to be foldable. 3, and includes a driving wheel 10, which can provide a driving force by human power, an auxiliary wheel 5, and a chair 7.

Although not shown, the wheelchair 1 of the present embodiment includes a battery and a known detecting device for detecting an assist timing, such as a hill, that requires a driving force for driving the driving wheels that is higher than usual. When the detection device detects the assist timing, power for moving the driving wheels 10 is supplied from the battery.

The wheel-integrated motor of this embodiment is
It is used as the drive wheel 10 of the wheelchair thus configured. Hereinafter, the wheel-integrated motor is also denoted by reference numeral 10.

Next, the wheel-integrated motor 10 of this embodiment will be described.

Here, FIG. 2A is a plan view of the wheel-integrated motor of this embodiment, and FIG. 2B is a sectional view taken along the line AA 'of FIG. In FIG. 2A, the portion above the line BB ′ is
FIG. 3 is a plan view of the vehicle body frame with an outermost wheel disc removed, and a plan view above the line BB ′ with the fixed disc removed.

As shown in FIG. 2, the wheel-integrated motor 10 is formed in a disc shape, and the center axis of the disc coincides with the center axis of the axle 11 fixed to the side frame 30 of the body frame 3. Fixed disk 1 fixed to axle 11
2 and a disk, the center axis of the disk and the axle 11
Are mounted so as to coincide with the center axis of the axle 11, are rotatably mounted on the axle 11 using the bearings b1 to b4, and are mounted so as to sandwich the fixed disk 12, and are disposed close to each other on the axle And a pair of wheel discs 14 attached thereto. The wheel disk 14 is formed in a disk shape having a diameter larger than that of the fixed disk 12, and is formed in such a size that the fixed disk 12 is completely contained in the near space a formed by the pair of wheel disks 14. .

The wheel-integrated motor 10 includes a wheel rim 16 mounted on an outer peripheral portion of the wheel disc 14.
And a rubber tube tire 18 attached to the wheel rim 16.

Further, the wheel-integrated motor 10 is provided with a hand rim 20 for a user on the wheelchair 1 to give a driving force by hand. This hand rim 20
Is fixed to the outer peripheral end of the wheel disk 14 together with the wheel rim 16 using a fixing pin P.

Meanwhile, in the wheel-integrated motor 10 thus configured, the fixed disk 12
As shown in (a), a plurality of field coils 22 formed in a rectangular shape with rounded corners are provided. A plurality of the field coils 22 are arranged along the circumferential direction such that the longitudinal direction thereof coincides with the radial direction of the fixed disk 12.

On the other hand, a rotor magnet 24 having a substantially rectangular shape and different polarities is provided on the wheel disk 14 along a back yoke 26 along the circumferential direction of the wheel disk 14.
Are installed through the Internet. Also, this rotor magnet 2
4 is attached so that its longitudinal direction substantially coincides with the radial direction of the wheel disk 14 and along the circumferential direction. Further, the rotor magnets 24 are arranged such that the opposite polarities of the rotor magnets 24 between the two wheel disks 14 are different.

The rotor magnet 22 is a magnet made of a rare earth element and having a thickness of 4 mm. Specifically, for example, Nd-F
eB is used as the material.

In the wheel-integrated motor 10 configured as described above, the field coil 2 mounted on the fixed disk 12
When power is supplied to the wheel 2, the rotor magnet 24 provided on the wheel disk 14 receives a driving force, and as a result, the wheel disk 14 rotates. This operation is exactly the same as that of a conventional axial type brushless motor. In the wheel-integrated motor 10 of this embodiment, the fixed disk 12 constitutes a stator and the wheel disk 14 constitutes a motor. Further, in the wheel-integrated motor 10, since the wheel disk 14 constitutes a part of the wheel, the wheel-integrated motor 10 of the present embodiment can be said to be one in which the motor and the wheel are integrally formed. .

The use of the wheelchair 1 having the above-described wheel-integrated motor 10 has the following effects.

First, the wheel-integrated motor 10 of the present embodiment
Since the motor and the wheels are integrally formed, no mounting space for installing the motor outside is required.

The wheel-integrated motor 10 of this embodiment
Since the wheel disk 14 constitutes a wheel,
By utilizing a plane parallel to the radial direction of the wheel, it is possible to secure an area for installing the rotor magnet 24 necessary for obtaining a driving force for directly driving the wheel. Accordingly, the wheel-integrated motor 10 of the present embodiment does not require a device corresponding to a speed reducer.

The wheel-integrated motor 10 according to the present embodiment
Is a so-called coreless structure in which the stationary disk 12 corresponding to the stator does not have a ferromagnetic material such as an iron core, so that no cogging torque is generated at all even when rotated in a non-excited state. For this reason, when the wheel-integrated motor 10 of this embodiment is used for a human-powered vehicle such as a wheelchair 1, the riding comfort is better than that of a conventional human-powered vehicle, and a light pushing is possible because no load due to cogging torque is applied. it can.

Further, the wheel-integrated motor 10 of the present embodiment
Uses a magnet made of a material made of a rare earth element which generates a stronger magnetic force than ferrite or the like as the rotor magnet 24. Therefore, in the wheel-integrated motor 10 of the present embodiment, the size and weight of the rotor magnet 24 itself can be made thinner and lighter in order to obtain a necessary magnetic force, as compared with a conventional rotor magnet made of ferrite or the like. .

Further, in the wheel-integrated motor 10 of the present embodiment, as shown in FIG.
Since the polarities of the rotor magnets 24 facing each other are different, most of the magnetic flux coming out of the rotor magnets 24 attached to the wheel disc 14 on one side is transmitted to the rotor magnets 24 attached to the wheel disc 14 on the other side. enter.
If there is no wheel disc 14 at the opposing position, the magnetic flux leaking to the next pole without passing through the coil near the boundary of the portion where the magnetism of the same wheel disc 14 is different increases, and it does not work effectively as generated torque, so efficiency Gets worse. Furthermore, since the two pairs of wheel discs 14 rotate together, no change in magnetic flux occurs between the two rotor magnets 24. Therefore, even if the motor rotates at a high speed, no eddy current is generated and the loss can be reduced.

Therefore, if the wheel-integrated motor 10 of the present embodiment described above is used as a driving wheel of the wheelchair 1, a reduction gear can be omitted, so that the weight of the entire wheelchair 1 can be reduced, and furthermore, the rare earth material can be reduced. Using the rotor magnet 24
Since the weight of the wheelchair 1 is reduced, the weight of the entire wheelchair 1 can be further reduced. Further, when the wheel-integrated motor 10 of this embodiment is used as a drive wheel of the wheelchair 1, the folding width can be reduced because no mounting space is required for installing the motor and the speed reducer. Therefore, when the wheel-integrated motor 10 of this embodiment is used as a drive wheel of the wheelchair 1, a wheelchair that is more portable than a conventional wheelchair can be manufactured.

When the wheel-integrated motor 10 of this embodiment is used as a driving wheel of the wheelchair 1, no cogging occurs, so that the riding comfort is better than that of a conventional wheelchair, and the driver pushes lightly when running manually. Can be.

Although the wheelchair has been described in the above embodiment, it is needless to say that the present invention can be applied to a human-powered vehicle such as a bicycle that runs manually.

In the above-described embodiment, an example in which the present invention is applied to a wheelchair having an assist function is described. Etc.) may be used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wheelchair to which a wheel-integrated motor according to an embodiment is applied.

FIG. 2 is a plan view of the wheel-integrated motor according to the embodiment.

FIG. 3 is a sectional view of a conventional assist motor.

FIG. 4 is an explanatory diagram for explaining a direction of a magnetic flux generated by a wheel-integrated motor in the embodiment and the invention according to claim 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wheelchair, 3 ... Body frame, 5 ... Auxiliary wheel, 7 ... Seat chair part, 10 ... Drive wheel, wheel integrated motor, 12 ... Fixed disc, 14 ... Wheel disc, 16 ... Wheel rim, 18 ... Tire, 20: Hand rim, 22: Field coil, 24: Rotor magnet, 26: Back yoke, 30: Side frame, 32: Seat seat support frame,

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H621 AA02 BB02 BB06 BB07 GB03 HH01 JK07

Claims (3)

[Claims] 1. A wheel, which is rotatably mounted on an axle fixed to a vehicle body and has a central axis disposed close to a pair of wheel discs coaxial with the axle, and is formed between the wheel discs. A fixed disk disposed in the near space and fixed to the axle; a field coil provided on a plate surface of the fixed disk; and a field coil provided on a plate surface of the wheel disk opposed to the field coil. A wheel-integrated motor comprising: a rotor magnet; and operating the wheel as a rotor and the fixed disk as a stator. 2. The wheel-integrated motor according to claim 1, wherein the rotor magnet is a magnet using a material made of a rare earth element. 3. The wheel-integrated motor according to claim 1, wherein the rotor magnets having different polarities are alternately arranged on each of the pair of wheel disks along a circumferential direction of the wheel disk. In addition, the pair of wheel discs are positioned so that the polarity of the rotor magnets facing each other is different between the two wheel discs.