JP2004025941A - Drive for power-assisted bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive for a power-assisted bicycle, which enhances heat radiation from a driving motor built in a rotary drum of a wheel section and quickly drains infiltrating water. <P>SOLUTION: In assisted operation, when the driving motor bears large load and temperature in the rotary drum rises, heat is properly radiated and temperature rise in the DC brush motor can be prevented. This is because that two brushes 14 are arranged in a lower portion at an acute angle with respect to each other and a plurality of air vents 23 for motor cooling are formed in a side of the rotary drum 8. When rainwater infiltrates into the rotary drum 8 through the air vents 23 for motor cooling and through a plurality of air vents 24 serving also for water drainage, the rainwater is discharged outside through the air vents 24 that serve also for water drainage and face down. The rainwater is prevented from causing high humidity in the rotary drum and from damaging parts of a control circuit or the like and does not cause problems of layer short and the like due to rust and insulation decrease. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving unit of an electric assist bicycle that assists a driving force of human power by a driving force of a motor.
[0002]
[Prior art]
Recently, an electric bicycle that has both a human-powered drive unit and a motor-driven electric drive unit, drives a motor in accordance with the magnitude of the human-powered drive force, and assists the human-powered drive force with the motor drive force, a so-called electric bicycle. Electric-assisted bicycles are gaining in popularity.
[0003]
An example of such a drive-type electric assist bicycle will be described with reference to the drawings. FIG. 1 is an overall perspective view of an assist bicycle, in which a battery 2 is installed below a front basket 1 of the assist bicycle body, and a motor drive unit is installed in a rear wheel hub 3. The pedaling force by the human is transmitted to the human input unit of the rear wheel drive unit via the pedal 4, the crank 5, and the chain 6.
[0004]
The drive motor built into the rotating drum of the rear wheel part is composed of a stator and a rotor. The stator and the casing have a cylindrical yoke made of cast iron with a magnet fixed to the inner surface, and a motor cover fixed to the bicycle body. Some of them are sandwiched from both sides.
[0005]
In addition, in order to reduce the size of the drive unit of the electric assist bicycle, it is necessary to reduce the size of the motor. The stator yoke of the drive motor is arranged in the rotating drum of the wheel unit, and the casings are arranged on the left and right sides of the stator yoke. There has been proposed a configuration in which the stator of the drive motor is formed integrally with the stator and the casing by screwing or the like through a casing mounting screw hole to reduce the size of the motor.
[0006]
[Problems to be solved by the invention]
However, because the drive motor is of a sealed type for waterproofing, if the size is reduced, the temperature generated in the DC brush motor will increase due to the heat generated inside, so it is necessary to take measures to prevent motor burnout when climbing a hill. Become. A simple means for preventing the temperature rise is to make a hole in a rotating drum that rotates together with the wheels and cool the hole. However, it is necessary to take measures against problems such as rust and rare short due to a decrease in insulation due to infiltration of rainwater. In addition, even if it is a closed type, water may infiltrate from unexpected places such as the gap between the rotating drum and the axle, but because of the closed type, the intruded water can not go out of the rotating drum, This causes the inside of the drum to have a high humidity or the like, causing damage to components such as a control circuit provided inside.
[0007]
Accordingly, the present invention provides a drive unit of an electric assist bicycle that can increase the heat radiation of a drive motor built in a rotating drum of a wheel portion, can quickly drain infiltrated water, and can reduce the size of the motor. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a driving unit of an electric assist bicycle according to claim 1 of the present invention includes a rotating drum that rotates with the wheel around an axle of the wheel, a motor and a reduction mechanism built in the rotating drum. In the drive unit of an electric assist bicycle that drives the wheels by electric driving force of a motor in addition to the manual driving force of human power, a cooling air hole is provided in the rotating drum, and a power supply unit to the motor or The configuration was such that the power supply cord hole was located below.
[0009]
According to a second aspect of the present invention, there is provided a driving unit for an electric assist bicycle, comprising: a rotating drum that rotates together with the wheel around an axle of the wheel; a motor and a reduction mechanism built in the rotating drum; In the drive unit of the electric assist bicycle, which is driven by the electric driving force of the motor in addition to the manual driving force of human power, cooling air holes are provided on the side and bottom surfaces of the rotating drum, and a power supply unit or a power supply cord hole for the motor is provided. It was configured to be located below.
[0010]
Thereby, in the assist operation, in an operation state in which a large load is applied to the drive motor, the temperature in the rotary drum increases, but a plurality of motor cooling air holes are provided on a side surface of the rotary drum. Therefore, the heat is appropriately released and the temperature rise of the motor can be prevented. In addition, even if water enters the rotating drum, it is discharged to the outside through the air hole that also serves as a drain on the bottom surface, preventing the inside of the rotating drum from becoming high humidity, etc. Rare shorts and the like due to insulation deterioration can be prevented.
[0011]
The drive unit of the electrically assisted bicycle according to claim 3 of the present invention includes a rotating drum that rotates together with the wheel around an axle of the wheel, and a motor and a speed reduction mechanism provided inside the rotating drum. In a drive unit of an electric assist bicycle that drives wheels by electric driving force of a motor in addition to manual driving force by human power, a cooling air hole is provided in the rotating drum, and brushes for supplying power to the motor are formed at acute angles below each other. The brush was arranged such that the insertion hole of the brush or the power supply cord hole for the brush was located below.
[0012]
According to a fourth aspect of the present invention, there is provided a driving unit for an electric assist bicycle, comprising: a rotating drum that rotates together with the wheel around an axle of the wheel; a motor and a reduction mechanism built in the rotating drum; In the drive unit of the electric assist bicycle, which is driven by an electric driving force of a motor in addition to a manual driving force of a human power, a cooling air hole is provided in the rotating drum, and brushes for supplying power to the motor are arranged at acute angles below each other. The brush insertion hole or the power supply cord hole for the brush is disposed below, and the brush is covered with a substrate case.
[0013]
A driving unit of an electric assist bicycle according to claim 5 of the present invention includes a rotating drum that rotates together with the wheel around an axle of the wheel, a motor and a reduction mechanism built in the rotating drum, and In the drive unit of the electric assist bicycle, which is driven by an electric driving force of a motor in addition to a manual driving force of a human power, a cooling air hole is provided in the rotating drum, and brushes for supplying power to the motor are arranged at acute angles below each other. The brush insertion hole or the power supply cord hole to the brush is arranged below, and a substrate case covering around the brush is arranged above the brush.
[0014]
A drive unit of an electric assist bicycle according to claim 6 of the present invention includes: a rotating drum that rotates together with the wheel around an axle of the wheel; a motor and a reduction mechanism built in the rotating drum; In the drive unit of the electric assist bicycle, which is driven by an electric driving force of a motor in addition to a manual driving force of a human power, a cooling air hole is provided in the rotating drum, and brushes for supplying power to the motor are arranged at acute angles below each other. Then, the brush insertion hole or the power supply cord hole to the brush is arranged downward, and the substrate case covering around the brush is arranged so as to cover the motor cover.
[0015]
According to a seventh aspect of the present invention, there is provided a drive unit for an electrically assisted bicycle, wherein the substrate case according to the fourth to sixth aspects is formed by molding and waterproofing.
[0016]
As a result, the two brushes are arranged at an acute angle below each other, the brush replacement openings also serving as holes for the code lines are formed downward, and the brush replacement openings and the periphery thereof are molded. Covering with a waterproofed board case, or disposing the board case above the brush, or covering the motor case so that rainwater or the like that has entered from above the brush is directly applied to the brush and the power supply terminal portion Can be prevented.
[0017]
According to an eighth aspect of the present invention, in the driving section of the electrically assisted bicycle according to any one of the fourth to seventh aspects, a power supply cord is wired between the board case and the motor case. Configuration.
[0018]
Thus, the power supply cord is wired using the gap between the board case and the motor case, so that it is possible to easily secure the storage position of the cord that requires attention when it is arranged at the same place as the rotating body.
[0019]
According to a ninth aspect of the present invention, there is provided a drive unit for an electrically assisted bicycle according to any one of the first to eighth aspects, wherein a sensor is attached to the rotating drum, and the sensor is mounted on a surface of a sensor case to which the sensor is attached. The configuration was such that irregularities were formed.
[0020]
As a result, irregularities are formed on the surface of the torque sensor case to make the surface uneven, so that when the torque sensor rotates with the axle, the irregularities agitate the air in the rotating drum to reduce the cooling effect of the motor. And the size of the motor can be reduced.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a drive unit of an electric assist bicycle according to the present invention will be described with reference to the drawings. The present invention can be applied to either a front wheel drive type or a rear wheel drive type. FIG. 2 is a configuration diagram of the rotary drum. FIG. 2A is a front cross-sectional view of a structure of a driving unit built in the rotary drum of the rear wheel, and FIG. 2B is a side view. The structure of the rear wheel hub 3 is roughly divided into: a rotating drum 8 that rotates in conjunction with the rear wheel; and a fixed casing 9 that is fixed to the axle 7 of the assist bicycle main body. Spokes are installed.
[0022]
The rotary drum 8 of the rear wheel is provided with a human input unit 11 composed of a sprocket mounted on the axle 7, a transmission 12 having a planetary gear (not shown), a torque sensor 16, a motor stator core 20 and a brush 14. In addition, a speed reducer including a rotor 17 fixed to a motor shaft disposed inside the stator core 20 and a planetary gear 13 for transmitting the rotational force of the rotor 17 to the rotating drum 8 is built in.
[0023]
Further, a board case 15 for accommodating a motor control circuit is fixed to the fixed casing 9, a cap casing 10 is provided at the other end of the axle 7, and a brake 19 is arranged at the fixed casing 9. A plurality of air holes 23 for cooling the motor and air holes 24 for draining water are provided on the side and bottom surfaces of the rotating drum 8. As a result, as shown in the side view of the rotary drum 8 from the human input unit 11 side in FIG. 2B, the plurality of air holes 23 provided in the rotary drum 8 and the human input unit 11 are arranged.
[0024]
FIG. 3 shows a detailed view of the arrangement of the air holes 23 and 24. FIG. 3A shows a part of a front cross-sectional view of the outer periphery of the rotating drum 8, in which a plurality of motor cooling air holes 23 and a plurality of water draining air holes 24 are arranged on the outer periphery of the rotating drum 8. FIG. 3B is a sectional view of the rotary drum 8 taken along a dotted line, and a plurality of air holes 24 for both draining are arranged at equal intervals around the rotary drum 8.
[0025]
4A and 4B are side cross-sectional views of a structure of a driving unit built in the rotating drum, and FIG. 4B is a sectional view for explaining a mounting state of a brush peripheral member. FIG. 3 is a cross-sectional view taken along a dashed-dotted line in FIG. Here, the reference numerals of the respective parts of the rotary drum in FIG. 4 are the same as those in FIG. The two brushes 14 are arranged at an acute angle below each other. This protects against direct effects of infiltrated rainwater and the like.
[0026]
FIG. 5 is an explanatory view of another embodiment relating to the attachment of the brush peripheral member. FIG. 5A is a partial cross-sectional side view of the structure of the driving unit built in the rotary drum, and FIG. 5B is a cross-sectional view taken along a dashed line in FIG. 5A. Here, the reference numerals of the respective parts of the rotary drum in FIG. 5 are the same as those in FIG. The two brushes 14 are arranged at an acute angle to each other below, and the brush replacement openings 25 are formed downward so that the brushes can be easily replaced while also using the holes of the cord wires 22.
[0027]
FIG. 6 is an explanatory view of still another embodiment relating to the attachment of the brush peripheral member. FIG. 6A is a partial side sectional view of the structure of the driving unit built in the rotary drum, and FIG. 6B is a sectional view taken along a dashed line in FIG. 6A. Here, the reference numerals of the respective parts of the rotary drum in FIG. 6 are the same as those in FIG. The two brushes 14 are arranged below at an acute angle to each other, and the brush replacement openings 25 which also serve as holes of the code wires 22 are formed downward. Further, the brush replacement opening 25 of the brush 14 and its periphery are molded and covered with a waterproof and waterproof substrate case 26.
[0028]
As shown in FIG. 6, the substrate case 26 not only covers the brush replacement opening 25 of the brush 14 and its surroundings, but also has a configuration in which the substrate case 26 is disposed above the brush 14 or the substrate case 26 is a motor. It may be a form that covers the case.
[0029]
Next, an arrangement of the substrate case 26 above the brush 14 will be described with reference to an exploded view of FIG. 7 in which the arrangement relationship between the stator core 20, the brush 14, and the substrate case 26 is disassembled. In the drawings, the brushes 14 and 14 are different from the actual one and are arranged at an acute angle in the upper left direction. FIG. 4A shows a front sectional view of the stator core 20, and FIG. 4B shows a side sectional view. ing.
[0030]
The stator core 20 is sandwiched and held by the left and right motor cases 18 in the rotating drum 8. The motor case 18 is fixed to the fixed casing by screws. A magnet 27 is inserted into a magnet insertion hole formed in the stator core 20, and one pole is constituted by two adjacent magnets 27. A rotor (not shown) is rotatably arranged inside the magnet.
[0031]
FIG. 7C is a side sectional view of the board case 26, and FIG. 7D is a front sectional view. The board case 26 is fitted to the motor case 18, and covers around the brush 14 except for the brush 14. That is, when the two brushes 14 are arranged below at an acute angle to each other, they cover the upper periphery of the brushes 14. Since the board case 26 is formed of a molded and waterproofed product, rainwater or the like that has entered from above the brush 14 is prevented from splashing on the brush 14.
[0032]
Further, by forming the wiring groove 28 in a part of the stator core 20, the power supply cord 22 introduced therethrough can be wired through a gap between the board case 26 and the motor case 18.
[0033]
8A and 8B are external views of the torque sensor 16 mounted in the rotary drum 8, FIG. 8A is a front view of the torque sensor case 29, and FIG. 8B is a side view of the case 29. Protrusions 30 and 31 are formed on the surface of the case 29 to make the surface uneven and uneven. Thus, when the torque sensor 16 rotates together with the axle 7, the air in the rotary drum 8 is agitated by the unevenness to enhance the cooling effect of the motor.
[0034]
The drive motor in the rotating drum configured as described above supplies the current from the power supply cord line 22 to the armature winding of the rotor 17 via the brush 14 and the commutator 21, and transmits the rotational force to the planetary gears. It is configured to be transmitted to the rotating drum 8 via a three-stage gear reducer 13 composed of a device.
[0035]
The planetary gear device serving as a reduction gear includes an external gear and three planetary gears 13, one of the planetary gears 13 is held by a motor cover 18 also serving as a planetary gear carrier, and the other is held by a planetary gear plate. A pinion gear is formed at one end of a rotatable motor shaft to which the rotor 17 is fixed, and is engaged with the planetary gear 13. Further, the planetary gear 13 is engaged with an external gear fixed to the rotary drum 8. Thus, the rotational force of the rotor 17 is reduced and transmitted to the rotating drum 8.
[0036]
When the driver steps on the pedal 4, the crank 5 rotates, which is transmitted to the human power input unit 11 via the chain 6, and the torque corresponding to the pressing force is detected by the torque sensor 16 via the transmission 12, It is supplied to a motor control circuit in a board case 15 fixed to the casing 9. The motor control circuit controls the driving force of the motor according to a program according to the magnitude of the driving force by human power, and assists the driving force of human power by the driving force of the motor.
[0037]
In such an assist operation, in an operation state in which a large load is applied to the drive motor, that is, when climbing a long uphill, the temperature in the rotary drum increases, but the side surface of the rotary drum 8 Since the motor cooling air holes 23 are provided, the heat is appropriately released and the temperature rise of the DC brush motor can be prevented.
[0038]
Also, even if water infiltrates into the rotary drum 8 or rainwater enters through the motor cooling air holes 23 and the plurality of water draining air holes 24, the water draining air holes 24 which face downwards are used. It is prevented from being discharged to the outside and damaging the components such as the control circuit due to high humidity inside the rotary drum and the like, and does not cause a problem such as rust or rare short due to reduced insulation.
[0039]
The two brushes 14 are arranged below at an acute angle to each other, and the brush replacement openings 25 also serving as holes for the code wires 22 are formed downward, respectively. Is covered with a board case 26 that has been subjected to waterproof treatment, or is disposed above the brush 14 with the board case 26, or the board case 26 covers the motor case so that rainwater or the like that has entered from above the brush 14 can be brushed. 14 and the power supply terminal portion can be prevented from being directly applied.
[0040]
Furthermore, since the protrusions 30 and 31 are formed on the surface of the torque sensor case 29 to make the surface uneven and uneven, the air in the rotary drum 8 is removed when the torque sensor 16 rotates together with the axle 7. The unevenness is agitated to enhance the cooling effect of the motor, and the motor can be downsized.
[0041]
【The invention's effect】
As described above, the driving unit of the electric assist bicycle according to the present invention provides a plurality of motor cooling air on the side surface of the rotating drum even when a large load is applied to the driving motor and the temperature inside the rotating drum increases in assist driving. The heat is appropriately released from the holes to prevent a rise in the temperature of the drive motor, and rainwater or the like that has infiltrated into the rotating drum is discharged to the outside through a downwardly-drained air hole that serves as a drain. Damage to components such as the control circuit due to humidity or the like can be prevented, and the drive unit can be protected from problems such as rust and rare shorts due to reduced insulation.
[0042]
Further, by covering the brush replacement opening and the power supply terminal portion with the waterproofed board case, it is possible to prevent rainwater or the like that has entered from above the brush from directly splashing. Further, by forming uneven portions on the surface of the torque sensor case to make the surface uneven, the unevenness agitates the air in the rotating drum when the torque sensor rotates with the axle, thereby increasing the cooling effect of the motor. Therefore, the size of the motor can be reduced.
[Brief description of the drawings]
FIG. 1 is an overall view of an electric assist bicycle.
FIG. 2 is a configuration diagram of a rotary drum of the present invention.
FIG. 3 is a detailed view of an arrangement of air holes in a rotating drum.
FIG. 4 is an attached state diagram of a brush peripheral member of the present invention.
FIG. 5 is another mounting state diagram of the brush peripheral member of the present invention.
FIG. 6 is another mounting state diagram of the brush peripheral member of the present invention.
FIG. 7 is an arrangement diagram of a stator, a brush, and a substrate case of the present invention.
FIG. 8 is an external view of a torque sensor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Front basket 2 Battery 3 Rear wheel hub 7 Axle 8 Rotary drum 9 Fixed side casing 10 Cap casing 11 Human input section 12 Transmission 13 Reduction gear 14 Brush 15 Board case 16 Torque sensor 17 Rotor 18 Motor case 20 Stator core 21 Commutator 22 Cord wire 23 Cooling air hole 24 Water draining air hole 25 Brush replacement opening 26 Board case 27 Magnet 28 Code groove 29 Torque sensor case 30, 31 Convex part

Claims (9)

A rotating drum that rotates together with the wheel around the axle of the wheel, and a motor and a speed reduction mechanism built in the rotating drum, wherein the wheel is driven by an electric driving force of the motor in addition to the manual driving force of the human power A driving unit for an electrically assisted bicycle, wherein a cooling air hole is provided in the rotating drum, and a power supply unit or a power supply cord hole for the motor is disposed below. The drive unit of an electric assist bicycle according to claim 1, wherein the cooling air holes are arranged on a side surface and a bottom surface of the drum. The drive unit of an electric assist bicycle according to claim 1, wherein the power supply unit is formed of a brush, and the brushes are arranged at an acute angle below each other. 4. The drive unit for an electrically assisted bicycle according to claim 1, wherein a periphery of the brush is covered with a substrate case. The drive unit for an electrically assisted bicycle according to claim 4, wherein a board case that covers the periphery of the brush is disposed above the brush. The drive unit of an electric assist bicycle according to claim 4, wherein the board case covers a motor cover. 7. The drive unit for an electrically assisted bicycle according to claim 4, wherein the board case is formed by molding and waterproofing. The drive unit for an electric assist bicycle according to claim 4, wherein a power supply cord is wired between the board case and the motor case. The electric driving force is driven in accordance with the human driving force, a sensor for detecting the human driving force is attached to a rotating drum, and irregularities are formed on a surface of a sensor case to which the sensor is attached. The drive unit of the electric assist bicycle according to any one of claims 1 to 8.

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