Brushless Motor Starter for Straddled Vehicle Space
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Solution Overview
Problem
In MT-type straddled vehicles, there is a need for higher flexibility in arranging components above the crankcase while minimizing the decline in starter motor functions.
Innovation Solution
The use of a multiphase brushless motor as both a starter motor and a generator allows for the removal of the conventional starter motor from the higher region, creating space for other components, with the motor driver being positioned under the seat to manage heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional starter motor is arranged in the region higher than the crankcase, then the starter motor can drive the crankshaft to start the engine, but the arrangement flexibility of components in that region is restricted and space for other components is limited
Solution Approach 1:
The patent applies multi-functionality by using a multiphase brushless motor that serves dual purposes: as a starter motor to drive the crankshaft during engine startup, and as a power generator during vehicle operation. This eliminates the need for a separate conventional starter motor in the restricted region, thereby improving arrangement flexibility while maintaining starter motor function through the integrated brushless motor system
2Ease of operation
If the motor driver is positioned in the region higher than the crankcase, then it can control the starter motor, but heat generated by the motor driver cannot be dissipated effectively
Solution Approach 1:
The patent resolves the heat dissipation issue by relocating the motor driver from the vertically constrained region higher than the crankcase to the horizontal space under the seat. This dimensional relocation allows the motor driver to be positioned in an area with adequate airflow and thermal management capacity, enabling effective heat dissipation while maintaining control functionality through electrical connections
3Volume of stationary object
If a multiphase brushless motor is used as both starter motor and power generator, then space is created in the region higher than the crankcase, but the motor driver generates heat during vehicle travel
Solution Approach 1:
The patent extracts the motor driver from the region higher than the crankcase and relocates it to the space under the seat. This separation removes the heat-generating component from the engine compartment, creating cooler operating conditions and freeing up space in the originally occupied region while maintaining all control functions through electrical wiring
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances flexibility in component arrangement above the crankcase without compromising starter motor functions, improving space utilization and heat management.
Implementation Method 1
a multiphase brushless motor that serves also as a power generator is provided as the starter motor at the end part of the crankshaft
Implementation Method 2
The motor driver also performs switching of the electric current generated by the starter motor. Accordingly, heat is generated in the motor driver while the vehicle is travelling
Implementation Method 3
when the vehicle is traveling, the air does not remain and is free to flow. Accordingly, when the motor driver is arranged under the seat, heat of the motor driver can be radiated easily
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The MT-type straddled vehicle according to the present teaching includes a seat that is supported by a seat frame, an engine, a multiphase brushless motor that starts the engine and that also serves as a generator driven by the engine to generate electricity, a motor driver that performs switching of the electric current to be supplied to the multiphase brushless motor, and an electric cable that connects the multiphase brushless motor to the motor driver. The motor driver is provided to two seat frames either directly or through a fixing member, in such a manner that the motor driver is fixed relative to the two seat frames, where at least a part of the motor driver is included within a seat frame space. The seat frame space is a space within the two seat frames when being viewed in the down direction of the MT type straddled vehicle from above, and the seat frame space is formed where downward displacement of the seat can be accepted thereinto.