JP2015112924A - Motor-bicycle front wheel drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel unit to be attached to a motor bicycle in order that a motor bicycle travels over a slippery road surface such as on snow, sand, or mud road where forward movement is difficult.SOLUTION: A travel unit that drives the front wheel 10 serving as a non-driving wheel 10 is mounted on a motor bicycle of rear-wheel drive. This unit is constituted of a control part 4, a drive part 5, and a transmission part 6. The output of an electric motor 8 is reduced by restricting an effectively working speed range to a low-speed one to save energy. As a result, the electric motor 8 is miniaturized to enable operation on electric power with a battery 3 that is standard equipment of the motor bicycle, thereby dispensing with the addition of a power source to constitute the unit to be miniaturize and lightweight. A propulsive power is increased by giving driving power to not only the rear wheel but also the front wheel, so that start regarded as difficult on a slippery road surface can be assisted to improve a travel performance.

Description

The present invention relates to a traveling device that is attached to a motorcycle so that the motorcycle travels on a road surface that is slippery and difficult to move forward, such as on snow, ice, sand, and muddy ground.

Motorcycles are indispensable for people's lives as an easy means of transportation. In snowy areas, motorcycles deliver mail and newspapers even when there is snow. In addition, due to its good mobility, it can be expected to play an important role in transporting goods and saving lives in the event of a disaster.

The motorcycle is a rear wheel drive except for a part. The motorcycle starts by driving the rear wheels with the power generated by the prime mover and converting the driving force into propulsive force using the frictional force acting on the contact surface between the tire and the road surface that forms the outer periphery of the rear wheel. be able to. However, it is difficult to obtain a frictional force on slippery road surfaces such as snow, ice, sand, and muddy ground, and the driving wheel rotates idly and the motorcycle cannot start. On softer road surfaces, the wheels are buried, and in order to start, the snow, sand and mud accumulated in the traveling direction of the wheels must be overcome or pushed away, which acts as resistance and hinders starting. Measures such as changing to snow tires or winding a chain to prevent slipping are taken, but the driving wheels are only rear wheels, so it is difficult to start because the driving force exceeding the driving resistance is not obtained, driving performance There was a limit.

The example that was implemented while there was a need to drive the front wheels in addition to the rear wheels, such as a four-wheel drive vehicle, was only partially adopted for off-road racing vehicles. The power source of the front wheels of the competition vehicle uses hydraulic pressure, and there is no example using electric power. The reason is that motorcycles have problems of space and weight. Hybrid technology has been established in the automobile field, but the power source of the electric motor is a storage battery mounted separately from the battery. In the case of an automobile, a storage battery can be mounted under the floor (although engineers think that downsizing was difficult), the increase in weight has little effect on handling stability. On the other hand, there is no space for a storage battery in a motorcycle, which has an adverse effect on handling stability due to weight increase.

In order to solve the problems of the motorcycle as described above, there have been the following techniques. In the invention disclosed in Japanese Patent Laid-Open No. 7-242190, the driving force is increased by using a device for driving the front wheels, which are non-driven wheels, on a motorcycle driven by the rear wheels, and the running performance on a slippery road surface is improved. It is improving. An electric motor is arranged above the front wheel in a posture perpendicular to the front fork, and the generated output is transmitted to the drive shaft arranged parallel to the front fork by the bevel gear, and the front wheel is driven by the bevel gear at the lower end of the drive shaft. Yes. It is characterized in that the heaviest electric motor and gear box among the components constituting the apparatus are arranged close to the center of rotation of the rudder. When operating the rudder, the device moves with the rudder, but placing a heavy object at the center of rotation reduces the inertia when manipulating the rudder and minimizes adverse effects on steering stability. Yes.

Japanese Unexamined Patent Publication No. 7-242190

However, the traveling device described above has the following problems. The weight of a motorcycle is around 100 kg, and if it becomes an electric motor that can assist in its driving, the output must be increased, and the transmission system also requires strength. In the above disclosed technique, in addition to the drive shaft arranged in parallel to the front fork, there are two drive shafts arranged vertically, and a gear is attached to each end to transmit the drive. Since all the components are required to be strong, the apparatus becomes large and heavy, and a large inertia is generated for operation. In addition, there is resistance where gears mesh when driving. A large number of large gears causes a large output loss.

As a result, a large electric motor that can withstand large inertia and large output loss for operation is required. Since a large electric motor has an adverse effect on steering stability, it is necessary to place the mounting position at the center of rotation of the rudder, and there are restrictions on the layout. As a result of having to increase the output of the electric motor, it is necessary to increase the size of the battery as the power source, and there are restrictions on the layout. The increase in weight and restrictions on the layout due to the electric motor and battery mounted on the motorcycle are no longer the easy means of transportation inherent in motorcycles.

The present invention solves the above-described problems and provides a small, lightweight and energy-saving traveling device. The traveling device of the present invention is characterized by being exhibited when the vehicle speed is low. By limiting the speed range where the driving force is exerted to a low speed, the apparatus can be reduced in size, weight and energy saving.

Motorcycles are difficult to start on slippery roads because the drive wheels tend to slip. The feature is that it is the most difficult to move from the stop state. Once it starts moving, it is easy to continue moving forward, but it is wise to drive without increasing speed because there is a risk of falling on slippery surfaces. In such a slippery road surface condition, the vehicle speed is limited to a low speed, so that means for avoiding a state where the vehicle cannot move forward only needs to be operated at a low speed.

In the traveling device of the present invention, the torque generated by the electric motor is increased by a large reduction ratio and transmitted to the front wheels. By setting the reduction ratio large, the motor output for obtaining the required torque for starting can be reduced, and the electric motor that is a heavy object can be made smaller and lighter. Less motor output means energy saving. There is no need to add a power source because it can be powered by the battery supplied as standard equipment on motorcycles. Further, the strength of the transmission system may be small. As a result, the entire device can be reduced in size and weight, and there are few restrictions on layout.

A large reduction ratio is used as a means to save energy in a compact and lightweight device. However, if the output characteristics of the electric motor are high torque, the transmission system configuration for increasing the reduction ratio is reduced or omitted. be able to. Then, the form of the in-wheel motor which integrated the hub and the electric motor can also be employ | adopted.

A large driving force by the front wheels may affect maneuverability. Since the driver is used to the characteristics of the rear wheel drive, the driver feels uncomfortable with the characteristics of the front wheel drive. As in the example of a four-wheeled vehicle, the cornering characteristics of a front-wheel drive vehicle are unique, and this is especially true for two-wheeled vehicles that turn while tilting the vehicle body during cornering.
This device is designed so that there is no sense of incongruity in driving. The characteristics of the DC motor employed as an electric motor contribute to this. The DC motor generates the largest torque when the rotation speed is zero, and the torque decreases as the rotation increases. This characteristic is convenient for this apparatus, and means that the driving force of the front wheels decreases as the vehicle speed increases. In the speed range that affects maneuverability, the output of this device is very small. Therefore, it is not necessary to control the rotation speed of the motor according to the vehicle speed.

If the tires do not slip and the driving conditions are good, the vehicle speed can be further increased. As a result, the electric motor reaches the maximum number of revolutions that can generate torque. In a higher speed range, the vehicle speed exceeds the maximum peripheral speed of the front wheels that can be driven by the electric motor. The electric motor is turned by the driving force generated by the main prime mover, and becomes a running resistance. In order to prevent this, the electric motor is equipped with a clutch for releasing the force turned by the rotation of the wheel, and the running resistance is reduced. Since the drive transmission between the electric motor and the wheel is interrupted by the action of the clutch, the output of the motor may be turned off in a speed range equal to or higher than the maximum rotation speed of the electric motor. Subsequent travel is performed without front wheel driving force until the speed decreases. It has the same drive configuration as when no device is attached.

The driving force of the device, that is, the motor output, is turned on when the motorcycle is opened, and turned off before the accelerator is closed or the maximum rotational speed of the electric motor is reached. To protect the electric motor and the control system, the control circuit is provided with overcurrent protection.

The present invention can solve the problem of a motorcycle having a limited traveling performance on a slippery road surface, and has the following effects. When the traveling device of the present invention is attached to a motorcycle, it is possible to help start difficult on a slippery road surface such as on snow, ice, sand, muddy ground, and improve traveling performance in a low speed range. it can. Even if the front wheels are buried on a soft road surface, the risk of getting stuck is reduced because the front wheels work to escape.

Calculate how much the driving performance will actually improve. The force F by which the motorcycle moves forward on a slippery road surface is governed by the frictional force between the tire and the road surface.
F = μW
μ is a coefficient of friction between the tire and the road surface, and W is a load acting on the road surface of the tire. Assuming a small displacement motorcycle, the weight is 95kg + one driver is 55kg = 150kg in total. Since the load distribution before and after riding a motorcycle is 50:50, the load on the front and rear wheels is 75kg.

Calculate the forward force F of the rear-wheel-drive motorcycle. Because the friction coefficient between the tire and ice is 0.07, and the rear wheel load is 75kg,
F = 0.07X75 = 5.25kg
The driving force of a rear-wheel-drive motorcycle is 5.25 kg, which is approximately 2 ° in terms of climbing ability.

Next, the forward force F of the two-wheeled motorcycle with the front wheel driving force applied is calculated. Because the load on the front and rear wheels is 75kg,
F = 0.07X75X2 = 10.5kg
The driving force of a two-wheeled motorcycle is 10.5 kg, which is approximately 4 ° when converted to climbing ability.

Thus, it can be seen that when both the front and rear wheels are driven, the driving force and the climbing ability are both doubled as compared with the case where the driving wheels are only the rear wheels. Actually, the numerical value varies depending on various conditions, but it is certain that the running performance is improved. The device can be retrofitted to a rear-wheel drive motorcycle and can be removed if not needed.

Example 1 will be described. Fig. 2 is a right side view of a motorcycle with a front wheel drive device attached. Example 1 will be described. FIG. 2 is an enlarged view of the drive device of FIG. Example 1 will be described. FIG. 3 is a cross-sectional view of the drive device of FIG. 2 as viewed from above. Example 1 will be described. FIG. 3 is a cross-sectional view of the drive device of FIG. Example 1 will be described. FIG. 5 is a cross-sectional view of a cross-sectional line C of the drive device shown in FIG. Example 2 will be described. Fig. 2 is an enlarged view of a right side surface of a motorcycle equipped with a front wheel drive device.

Example 1, FIG. 1, FIG. 2, FIG. 3, FIG. 4 and FIG. FIG. 1 shows a state in which a front wheel drive device is attached to a motorcycle adopting a general rear wheel drive system. While the main prime mover 1 drives the rear wheels, the electric power generated by the generator 2 built in the main prime mover 1 is stored in the battery 3 that is standard on the motorcycle. The apparatus is divided into three parts: a control unit 4, a drive unit 5 of a mechanical part, and a transmission unit 6. The controller 7 of the control unit 4 supplies necessary power from the battery 3 to the electric motor 8 of the drive unit 5. The required power is determined by the accelerator opening detected by the throttle sensor 9. The electric motor 8 converts electric power into rotational power and transmits the chain to the transmission unit 6. The transmission unit 6 is attached to the front wheel 10 and drives the front wheel 10.

FIG. 2 shows the mounting state of the drive unit 5 of the present apparatus. The mounting stay 11 is fixed to the lower end of the front fork 12 with an axle shaft 13. The mounting bracket 14 is fixed so as to wind the outer periphery of the outer tube of the front fork 12. The main plate 15 is fixed by a mounting stay 11 and a mounting bracket 14. An electric motor 8 is fixed to the main plate 15, and a main shaft 18 that supports the driven gear 17 is rotatably attached. This device includes a gear cover 19 that waterproofs the gear and a chain cover 20 that prevents the human body from touching the chain 27.

FIG. 3 explains how the power of the electric motor 8 of the present apparatus is transmitted. This figure is a cross section taken along a cross sectional line A in FIG. A drive gear 21 concentrically fixed to the motor shaft of the electric motor 8 meshes with the driven gear 17 to transmit the rotational power of the electric motor 8. The driven gear 17 is fixed to the one-way clutch 22 concentrically. A motor cover 23 for waterproofing the electric motor 8 is provided.

FIG. 4 explains how driving is transmitted to the front wheel 10. This figure is a cross section taken along a cross sectional line B in FIG. The one-way clutch 22 is attached to the end of the main shaft 18 concentrically. The one-way clutch 22 performs drive transmission in an arbitrary rotation direction, but does not transmit drive in the counter-rotation direction. With this function, even if the vehicle speed exceeds the peripheral speed of the front wheels 10 driven at the maximum number of revolutions exhibited by the electric motor 8, the motor shaft is not forcibly rotated and travel resistance is reduced. The bearing holder 24 is fixed to the main plate 15. The outer ring of the flanged bearing 25 is inserted into the bearing holder 24, and the main shaft 18 penetrates through the inner ring so that the main shaft 18 is rotatable. A drive sprocket 26 is concentrically fixed to the other end of the main shaft 18. The driving force of the drive sprocket 26 is transmitted to the driven sprocket 28 via the chain 27. The driven sprocket 28 is fixed to the drive disk 29 concentrically. A drive disk 29 is fixed to the outer ring of the hub bearing 30, and a driven disk 31 is fixed to the inner ring. The two disks are rotatable, but the steel ball 32 works like a wedge, takes charge of the rotational direction of the two disks, and transmits the driving force. The driven disk 31 is concentrically fixed by a hub holder 33 to a hub 34 provided as a standard in a motorcycle. The front wheel 10 that is standard on the motorcycle is composed of a hub 34, spokes, rims and tires. Therefore, the rotational power of the electric motor 8 can be transmitted to the front wheels 10 as a driving force.

In order to increase the torque transmitted to the front wheels 10, a large reduction ratio is adopted. When the gear transmission is reduced to 14: 120 and sprocket transmission to 8:60, the torque generated by the electric motor 8 can be transmitted to the front wheel 10 by 64 times. In the first embodiment, chain drive is adopted as the final stage of the reduction gear, but gear drive is also possible. Although the one-way clutch 22 is adopted as the clutch of this embodiment, an electromagnetic clutch or a centrifugal clutch is also possible.

Next, the function of the steel ball 32 will be described. A steel ball 32 attached to the drive disk 29 presses the driven disk 31 by a spring 35. At this time, the steel ball 32 has fallen into the recess of the driven disk 31, and the driving force of the drive disk 29 can be transmitted to the driven disk 31 via the steel ball 32.
When the motorcycle according to this embodiment travels on a slippery road surface, it is assumed that the rear wheels are idle and cannot start. When the front wheel 10 does not idle, the motor shaft does not rotate even though the electric motor 8 generates torque. At this time, the torque generated by the electric motor 8 is maximized and the current value is also maximized, resulting in an overload state. The electric motor 8 generates heat, and if this state continues for a long time, it will burn out. It is effective to release the driving force by the electric motor 8 and reduce the current value before that happens.
The steel ball 32 functions as a torque limiter. When the drive disk 29 drives the driven disk 31, a force in the rotational direction is applied to the steel ball 32. However, if the force exceeds the arbitrary force, the force pressing the steel ball 32 by the spring 35 cannot withstand the driving force. The steel ball 32 moves toward the drive disk 29 (outside the vehicle body) by compressing the spring 35 so as to remove it from the depressed depression. Then, the driving force is released, the drive disk 29 and the driven disk 31 are rotatable, and the electric motor 8 is prevented from being burned out. When the drive disk 29 rotates 360 degrees, the steel ball 32 falls into the recess of the driven disk 31 and returns to the state where the driving force is transmitted. By changing the pressure applied to the spring 35 by the adjusting screw 36, the pressing force of the steel ball 32 can be adjusted and the characteristics can be changed. The function as a torque limiter is also effective for reverse rotation, and even when foreign matter is caught in the chain 27 and the drive system is locked, the force is released, and it can also be used as a fail safe that avoids falling due to the front wheel 10 locking Function.

The upper diagram of FIG. 5 shows a state where the drive is transmitted by the steel ball 32, and the lower diagram shows the moment when the drive force is released without being able to withstand a large drive force. In the figure below, the steel ball 32 removed from the depression 37 is advanced by θ °. Although the hollow 37 of the driven disk 31 in this figure is assumed to be circular, the characteristic can be changed by making it long in the circumferential direction. In this embodiment, the steel ball 32 and the depression 37 are assumed to be one place, but the characteristics can be changed by providing several places evenly in the circumferential direction.

FIG. 6 shows Example 2. Instead of the drive unit and the transmission unit of the first embodiment, a wheel 51 with an in-wheel motor can be replaced. In the second embodiment, the front wheel that is standard on the motorcycle is changed to a wheel 51 with an in-wheel motor. The control unit and the power source are the same as those in the first embodiment. The inside of the hub 52 is represented by a cutting line D and shows how the power of the electric motor 53 drives the front wheels. An internal gear 54 is concentrically fixed inside the hub 52 of the wheel 51 with the in-wheel motor, and has a structure that rotates together with the front wheel. A drive gear 55 is engaged with the internal gear 54, the drive gear 55 is concentrically fixed to the one-way clutch 56, and the one-way clutch 56 is coaxially attached to the motor shaft of the electric motor 53. The electric motor 53 is fixed to the hub cover 58 in a posture parallel to the axle shaft 57. However, the electric motor 53 does not need to be built in the hub 52, and is installed with the opposite side of the motor shaft facing the outside of the vehicle body. You may stick out. Non-rotating portions of the wheel 51 with the in-wheel motor are an electric motor 53, a hub cover 58, and an axle shaft 57. Therefore, the power of the electric motor 53 can drive the wheel 51 with the in-wheel motor.

The attachment procedure of Example 1 will be described. First, a method of attaching the transmission portion 6 to the motorcycle will be described with reference to FIG. Pull out axle shaft 13 and remove front wheel 10 from front fork 12. The mounting bracket 14 is attached to the front fork 12. The transmission unit 6 can be handled as an already assembled unit. The transmission unit 6 is attached to the hub 34 of the front wheel 10 and fixed using the hub holder 33. The chain 27 is wound around the driven sprocket 28, the front wheel 10 is returned to the front fork 12, and the axle shaft 13 is attached together with the mounting stay 11.
Next, a method of attaching the drive unit 5 to the motorcycle will be described with reference to FIG. The drive unit 5 can be handled as an already assembled unit. The drive unit 5 is applied to the mounting stay 11 and the mounting bracket 14, and the drive unit bolt 16 is temporarily tightened. Put chain 27 on drive sprocket 26. Applying a force upward to the drive unit 5 so that the chain 27 is stretched, and the drive unit bolt 16 is finally tightened. Install the chain cover 20.
Next, a method for attaching the control unit 4 to the motorcycle will be described with reference to FIG. Install the throttle sensor 9 where it can detect the accelerator opening, and wire the controller 7 to the battery. If the operation is confirmed, the installation work can be finished.

When the traveling device of the present invention is attached to a motorcycle, it can be used for the following applications. Means of transportation during snowfall. Patrol at the ski resort. Transportation of goods and lifesaving at the time of disaster. Means of transportation in the forest. Leisure sports.

1 Main prime mover
2 Generator
3 Battery
4 Control unit
5 Drive unit
6 Transmitter
7 Controller
8 Electric motor
9 Throttle sensor
10 Front wheels
11 Mounting stay
12 Front fork
13 Axle shaft
14 Mounting bracket
15 Main plate
16 Drive bolt
17 Driven gear
18 Main shaft
19 Gear cover
20 Chain cover
21 Drive gear
22 one-way clutch
23 Motor cover
24 Bearing holder
25 Bearing with flange
26 Drive sprocket
27 chain
28 Driven sprocket
29 Drive disk
30 Hub bearing
31 Driven disc
32 steel balls
33 Hub holder
34 Hub
35 Spring
36 Adjustment screw
37 depression
51 Wheel with in-wheel motor
52 Hub
53 Electric motor
54 Internal gear
55 Drive gear
56 one-way clutch
57 Axle shaft
58 Hub cover

Claims (4)

In order to drive a non-driven wheel different from the wheel driven by the main prime mover, a drive device having an electric motor as a prime mover is added later, or in a motorcycle in which a wheel with an in-wheel motor is replaced with the non-driven wheel, Motorcycle auxiliary drive device in which a reduction ratio is set so that the peripheral speed of the outer periphery of the wheel driven by the electric motor or the in-wheel motor is 24 km / h or less when the electric motor or the in-wheel motor exhibits the maximum rotation speed . In order to drive a non-driven wheel different from the wheel driven by the main prime mover, a drive device having an electric motor as a prime mover is added later, or in a motorcycle in which a wheel with an in-wheel motor is replaced with the non-driven wheel, A motorcycle auxiliary drive device that does not require a new power source by using electric power of a battery that is standard equipment on the motorcycle as a power source of the electric motor or the in-wheel motor. In order to drive a non-driven wheel different from the wheel driven by the main prime mover, a drive device having an electric motor as a prime mover is added later, or in a motorcycle in which a wheel with an in-wheel motor is replaced with the non-driven wheel, When a driving force or braking force exceeding the set value is generated in the rotational direction or counter-rotating direction of the wheel driven by the electric motor or the in-wheel motor, it is released and the driving force or control exceeding the set value is released. A motorcycle auxiliary drive device having a torque limiter function for preventing transmission of power. In a motorcycle to which a drive device using an electric motor as a prime mover is added to drive a non-drive wheel different from the wheel driven by the main prime mover, it is one of the parts constituting the non-drive wheel. The motor shaft, which is the rotating portion of the electric motor, is parallel to the axle shaft toward the inner diameter side of the ring-shaped rim, that is, the position approaching the axle shaft for axially mounting the non-driving wheel. Motorcycle auxiliary drive device characterized by being arranged in a posture of