Motorcycle EPS Actuator Layout for Dynamic Thrust Load Damping
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Solution Overview
Problem
In straddled vehicles equipped with EPS, the dynamic thrust load applied to the EPS actuator causes changes in power transmission conditions and requires larger component sizes for durability, complicating compact arrangement.
Innovation Solution
The EPS actuator is designed with upward and downward dynamic thrust load attenuation elastomer members to absorb and attenuate dynamic thrust loads in both directions, ensuring the rotor shaft movement is within allowable limits, maintaining gear mesh stability and preventing power transmission condition changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the EPS actuator is arranged with the rotor shaft extending in the up-down direction to achieve compact arrangement, then the device complexity is reduced, but the power transmission condition changes due to rotor shaft movement caused by dynamic thrust load
Solution Approach 1:
The patent introduces thrust load attenuation elastomer members as intermediary elements between the motor and the EPS actuator. These elastomer members absorb and attenuate the dynamic thrust load, preventing direct transmission of axial forces to the rotor shaft. This mediator approach allows the rotor shaft to remain stable in the axial direction while maintaining the compact vertical arrangement, thus resolving the contradiction between compact design and power transmission reliability
Solution Approach 2:
The elastomer members are pre-installed in the thrust load attenuation member to provide beforehand cushioning against dynamic thrust loads. This prior cushioning arrangement ensures that when thrust loads occur during vehicle operation, the elastomer members are already positioned to absorb and attenuate these forces, preventing rotor shaft displacement and maintaining stable gear meshing conditions
2Strength
If the size of components is increased to enhance durability against dynamic thrust load, then the strength is improved, but the device complexity and arrangement compactness deteriorate
Solution Approach 1:
Instead of increasing the size of critical components like the motor or gear parts to handle thrust loads, the patent introduces elastomer members as intermediary elements. These elastomer members specifically address the thrust load issue through their elastic properties, allowing the main components to maintain their original compact sizes while still achieving the required durability and load-bearing capacity
Solution Approach 2:
The patent changes the physical state and properties by introducing elastomeric materials with specific elastic moduli and damping characteristics. This parameter change allows the system to handle dynamic thrust loads through material deformation rather than through increased component size, thereby maintaining compact arrangement while enhancing durability
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 design achieves a compact EPS actuator arrangement while stabilizing power transmission to the steering shaft, reducing wear and maintaining gear mesh integrity despite dynamic thrust loads.
Implementation Method 1
an upward dynamic thrust load attenuation elastomer member disposed so as to allow the rotor shaft to move in the upward direction of the straddled vehicle, and to receive and attenuate a dynamic thrust load
Implementation Method 2
to receive and attenuate a dynamic thrust load that is applied in the upward direction
Data Source
Figure 1(A)~1(C)
AI summary
The present teaching aims to provide a straddled vehicle equipped with an EPS, capable of compact arrangement of an EPS actuator, with suppression of a change of a power transmission condition of the EPS actuator transmitting power to a steering shaft, the change being otherwise caused by a dynamic thrust load. A motor included in the EPS actuator is configured such that the sum of a maximum compression amount of an upward dynamic thrust load attenuation elastomer member, which is less than the height of an upward movement allowance space for allowing a rotor shaft to move in the upward direction when a dynamic thrust load in the upward direction is received, and a maximum compression amount of a downward dynamic thrust load attenuation elastomer member, which is less than the height of a downward movement allowance space for allowing the rotor shaft to move in the downward direction when a dynamic thrust load in the downward direction is received, can be shorter than the length in the up-down direction of a gear part having a longer length in the up-down direction out of a rotor gear part and a transmission gear part meshed with the rotor gear part.