Vehicle approach alert device for saddle-ridden electric vehicle

1. A vehicle approach alert device for a saddle-ridden electric vehicle that is attached to a vehicle body of the saddle-ridden electric vehicle having an electric motor included in a power engine, and that is provided with a sound emitter that emits an alert sound to a surrounding area for notifying the surrounding area of an approach of the saddle-ridden electric vehicle, wherein:

the alert sound of the sound emitter is controlled according to a traveling status of the saddle-ridden electric vehicle;

the sound emitter is arranged so that a direction of the alert sound is oriented diagonally downward and forward of the saddle-ridden electric vehicle,

the sound emitter raises a frequency of the alert sound with an increase in a rotation speed of the electric motor,

an increase rate of this alert sound frequency is set so as to be lower than an increase rate of the rotation speed of the electric motor, and

the alert sound is set to be in a range between 100 Hz and 800 Hz and includes:

a first sound having a frequency and serving as a reference sound,

a second sound having a frequency higher than the frequency of the first sound,

a third sound having a frequency higher than the frequency of the second sound, and

a difference of 1 subtracted from a ratio of the frequency of the second sound with respect to the frequency of the first sound is set to be greater than a difference of a ratio of the frequency of the second sound with respect to the frequency of the first sound subtracted from a ratio of the frequency of the third sound with respect to the frequency of the first sound.

2. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 1 , wherein:

the saddle-ridden electric vehicle is provided with a front cover that covers a periphery of a head pipe of a vehicle body frame; and

the sound emitter is arranged on an inner side of the front cover.

3. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 2 , wherein:

the saddle-ridden electric vehicle is further provided with a sound emission duct that extends diagonally downward and forward from the sound emitter along the alert sound direction; and

the sound emitter is attached to the vehicle body frame, on the inner side of the front cover, and emits the alert sound to an outer side of the front cover through the sound emission duct.

4. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 2 , wherein the sound emitter is arranged below the head pipe.

5. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 4 , wherein the sound emitter is arranged on an outer side of a front fender of the saddle-ridden electric vehicle.

6. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 2 , wherein:

the saddle-ridden electric vehicle is further provided with a vehicle body frame member that extends diagonally backward and downward of this saddle-ridden electric vehicle, from the head pipe;

on the head pipe there is steerably supported a front fork that extends diagonally forward and downward and that suspends a front wheel; and

the sound emitter is arranged in front of the vehicle body frame member and at the rear of the front fork when this saddle-ridden electric vehicle is seen from a side.

7. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 2 , wherein:

on the head pipe, there is steerably supported a front fork that extends diagonally forward and downward and that suspends a front wheel; and

the sound emitter is arranged in front of the front fork when this saddle-ridden electric vehicle is seen from a side.

8. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 1 , wherein:

the saddle-ridden electric vehicle is further provided with a driving unit that supports the electric motor and a driving wheel, and that is connected to the vehicle body frame so as to be able to swing vertically with respect to the vehicle body frame; and

the sound emitter is provided on the driving unit and also at a position below a driver's seat part.

9. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 8 , wherein:

the saddle-ridden electric vehicle is further provided with a unit cover that covers the driving unit; and

within the unit cover, there is arranged the sound emitter.

10. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 8 , wherein:

the saddle-ridden electric vehicle is a swing type vehicle such that the vehicle body frame swings left and right with respect to the driving unit having a pair of the driving wheels; and

the sound emitter is arranged above a swing mechanism that connects the driving unit and the vehicle body frame.

11. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 8 , wherein:

the saddle-ridden electric vehicle is further provided with a battery between the pair of driving wheels; and

the sound emitter is arranged in front of the battery.

12. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 1 , wherein the sound emitter is arranged on an inner side of an electrical component that is exposed to an outside of the saddle-ridden electric vehicle.

13. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 12 , wherein the electrical component is arranged in front of a head pipe of the vehicle body frame.

14. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 12 , wherein the electrical component is a head lamp that is arranged at a front end of the vehicle body.

15. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 12 , wherein the electrical component is a meter unit that is arranged at a front end of the vehicle body.

16. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 1 , wherein:

the saddle-ridden electric vehicle is further provided, at the rear of a head pipe of a vehicle body frame, with an exterior member having a knee grip part that is to be sandwiched between both knees of the driver; and

the sound emitter is arranged on an inner side of the exterior member.

17. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 16 , wherein the exterior member has an opening part that opens toward the direction of the alert sound.

18. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 16 , wherein the sound emitter is arranged within a front end part of the exterior member.

19. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 16 , wherein a driving control device for the power engine and an output control device for the sound emitter are arranged within the exterior member.

20. The vehicle approach alert device for a saddle-ridden electric vehicle according to claim 16 , wherein a battery that serves as a power supply for the sound emitter is arranged within the exterior member.