Steering Assist Speed Reducer With Single Torque Output
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Solution Overview
Problem
Conventional steering assistance devices have a larger size due to two lines of large torques being outputted to the rack shaft, which is unfavorable for downsizing.
Innovation Solution
A two-stage speed reducer with a crank shaft and oscillating gear configuration that decelerates the driving force from a motor and inputs the operation force from a human, ensuring a single line of final output to the steering mechanism, thereby achieving downsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pinion is mounted to the final output shaft of the speed reducer and meshes with a rack shaft, then the steering assistance force can be transmitted, but two lines of large torques are outputted to the rack shaft leading to a larger device size
Solution Approach 1:
The patent merges the motor-driven assistance force and the driver's operation force into a single torque transmission line. The operation force is input to the crank shaft which is already part of the speed reducer mechanism, combining both force sources before they reach the pinion-rack shaft interface. This eliminates the need for separate torque transmission paths and reduces the number of components required.
Solution Approach 2:
The crank shaft serves multiple functions: it receives the driver's operation force, transmits it through the speed reducer, and simultaneously serves as part of the motor-driven assistance transmission path. This multi-functionality allows both torque sources to be integrated into a single transmission line, reducing overall device complexity and size.
2Volume of moving object
If a two-stage speed reducer with crank shaft and oscillating gear is used to decelerate both driving force and operation force, then a single line of final output is achieved, but the gear train complexity increases
Solution Approach 1:
The patent employs an oscillating gear mechanism where the gear oscillates back and forth during operation. This dynamic motion allows the gear to engage with different teeth on the crank shaft during different phases of the oscillation cycle, enabling the transmission of both motor-driven and driver-applied forces through the same gear path without requiring separate static gear trains for each force source.
Solution Approach 2:
The speed reducer is divided into two stages: a first stage that decelerates the motor's high-speed driving force, and a second stage that decelerates the driver's operation force. This segmentation allows each stage to be optimized for its specific function while both stages share common components like the crank shaft, reducing overall complexity compared to having completely separate transmission paths.
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
The configuration allows for a compact design by transmitting the steering force in a single line, enabling the steering assistance device to be downsized while maintaining operational efficiency.
Implementation Method 1
an input gear fixed to the second rotation shaft, a third gear meshing with the input gear
Implementation Method 2
an oscillating gear to be oscillated by the crank shaft and internal teeth meshing with the oscillating gear
Implementation Method 3
a first bevel gear disposed on the first rotation shaft and a second bevel gear meshing with the first bevel gear, wherein the second bevel gear is connected to the crank shaft
Data Source
AI summary
An object of the present invention is to provide a steering assistance device that has a single line of final output, thereby to achieve downsizing. The assistance device of the present application includes a speed reducer configured to decelerate a driving force from a motor and output the decelerated driving force, wherein the speed reducer is configured to receive an operation force produced by an operation of a human.