Torque Transmission Joint With Elastic Spline Gaps for Reversal Noise
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Solution Overview
Problem
Existing torque transmission systems in electric power steering devices generate abnormal noise when reversing the rotational direction of the driving shaft due to backlash in the spline engagement portions between the output shaft and the worm shaft.
Innovation Solution
A torque transmission joint comprising an intermediate transmission member with concave-convex portions and elastic members that engage with the first and second transmission members, allowing for torque transmission with controlled circumferential gaps to reduce noise by elastic deformation and prevent separation, thereby suppressing abnormal noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If circumferential gaps are provided at spline engagement portion to allow swingable displacement, then abnormal noise is reduced during direction reversal, but torque transmission efficiency decreases
Solution Approach 1:
The spline engagement portion is designed with circumferential gaps that allow dynamic swingable displacement during operation. This dynamic capability enables the spline shaft to move slightly to accommodate direction reversals without generating abnormal noise, while the elastic members maintain continuous torque transmission through controlled engagement.
Solution Approach 2:
Elastic members are introduced as intermediary elements between the spline shaft and spline hole. These elastic members absorb and transmit torque while accommodating the swingable displacement enabled by circumferential gaps, thus maintaining torque transmission efficiency despite the presence of gaps that prevent rigid coupling.
2Object-affected harmful factors
If elastic members are used to transmit torque with circumferential gaps, then abnormal noise is suppressed by elastic deformation, but device complexity increases
Solution Approach 1:
The physical state of the torque transmission interface is changed from rigid to elastic by introducing elastic members. This parameter change allows the system to utilize elastic deformation to absorb impact and suppress abnormal noise during direction reversal, while the circumferential gaps provide the necessary freedom for swingable displacement.
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 solution effectively suppresses abnormal noise during rotational direction reversal by using elastic deformation to weaken contact forces and maintain torque transmission efficiency, improving the operational feeling of the steering wheel.
Implementation Method 1
configured to transmit torque with the intermediate transmission member by engaging with the first tooth portions... configured to transmit torque with the intermediate transmission member by engaging with the second tooth portions
Data Source
AI summary
A first concave-convex portion of a first transmission member is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being therebetween. A second concave-convex portion of a second transmission member is engaged with the intermediate concave-convex portion with a circumferential gap being therebetween. A first elastic member and a second elastic member are engaged with a first engagement portion and a second engagement portion of the intermediate transmission member such that separation between the intermediate transmission member and the first elastic member and the second elastic member can be prevented.