Steering Device Joint and Spur Gear Mechanism for Compact Single-Wheel Steering
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Solution Overview
Problem
The existing single-wheel steering devices face issues with size increase due to the rigid coupling of the output shaft and steering knuckle, which affects smooth steering and efficiency, and the speed reducer's design limits the reduction ratio, making the device bulky and inefficient.
Innovation Solution
A steering device with a joint that allows the steering knuckle to incline relative to the suspension arm, coupled with a coaxial high reduction mechanism and an electric motor fixed to the suspension arm, enabling smooth steering and reducing the device's size by using a constant velocity joint and a compact speed reducer configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output shaft of the speed reducer is rigidly coupled to the steering knuckle, then the steering force is transmitted directly, but the inclination of the kingpin axis caused by bound/rebound movement adversely influences smooth steering
Solution Approach 1:
A constant velocity joint is introduced as an intermediary component between the speed reducer output shaft and the steering knuckle. This joint allows the kingpin axis to incline during bound/rebound movements while maintaining smooth power transmission, thereby resolving the conflict between rigid coupling and steering smoothness.
2Power
If a face gear and pinion are used for the speed reduction mechanism, then the steering force is transmitted, but the efficiency is not necessarily high and the device size increases
Solution Approach 1:
The patent changes the gear configuration from a face gear and pinion system to a spur gear system. This parameter change improves transmission efficiency while reducing the overall device size, as spur gears have lower sliding friction and more favorable meshing characteristics for this application.
3Productivity
If a larger diameter face gear is used to obtain a high reduction ratio, then the reduction ratio increases, but the size of the steering device increases
Solution Approach 1:
The patent changes from a face gear configuration to a spur gear configuration, which allows achieving the same reduction ratio with a more compact design. The spur gear system has more favorable geometric parameters that reduce the overall volume while maintaining the required reduction ratio.
4Ease of operation
If the pinion is driven radially outwardly of the face gear, then the face gear can rotate, but the steering device size increases in the direction orthogonal to the kingpin axis
Solution Approach 1:
The patent changes the entire gear system from a face gear and pinion arrangement to a spur gear system. This parameter change allows the drive source to be positioned more compactly, reducing the footprint area in the direction orthogonal to the kingpin axis while still enabling proper rotation and power transmission.
Data Source
AI summary
A steering device, including: a steering knuckle rotatably holding a wheel; an electric motor and a speed reducer configured to decelerate rotation of the electric motor, the electric motor and the speed reducer being fixed to a suspension arm; and a joint through which the steering knuckle is supported by the suspension arm in a state in which a kingpin axis is allowed to incline with respect to the suspension arm, the joint coupling the steering knuckle and an output shaft of the speed reducer such that the steering knuckle pivots about the kingpin axis by an operation of the electric motor.