Torque Transmission Joint With Elastic Backlash Damping
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Solution Overview
Problem
Conventional electric-powered power steering apparatuses experience noise due to backlash in the spline engagement section between the output shaft of the electric motor and the worm shaft, which is inherent to allow for rocking displacement necessary for smooth operation.
Innovation Solution
A torque transmission joint with a combined body featuring an intermediate transmission member and elastic members with specific uneven sections and slits, allowing for controlled engagement and interference to mitigate noise by adjusting clearances and elastic deformations during torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If spline engagement is used to transmit torque between the output shaft and worm shaft, then torque transmission is achieved, but noise occurs due to backlash during reverse rotation
Solution Approach 1:
The patent introduces a damping element between the output shaft and worm shaft that预先 absorbs shocks and reduces impact forces during reverse rotation. This cushioning element mitigates the harmful effects of backlash before they can generate noise, while still allowing the spline engagement to transmit torque effectively.
Solution Approach 2:
The patent introduces a damping element as an intermediary component between the output shaft and worm shaft. This mediator absorbs vibrations and reduces the direct transmission of impact forces that cause noise, while still allowing torque to be transmitted through the spline engagement.
2Ease of operation
If clearance is provided in spline engagement to allow for rocking displacement of the worm shaft, then smooth operation is achieved, but backlash cannot be completely eliminated
Solution Approach 1:
The patent modifies the physical parameters of the engagement interface by introducing a damping element with specific viscoelastic properties. This changes the way clearance is managed - instead of rigid clearance that causes backlash, the system uses controlled elastic deformation that maintains contact while allowing necessary displacement for smooth operation.
Solution Approach 2:
The patent employs composite material properties by using a damping element made of viscoelastic material between the metal shafts. This composite approach combines the rigidity needed for torque transmission with the elasticity needed to eliminate backlash, achieving both smooth operation and precise engagement.
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 noise during reverse rotation of the drive shaft by managing backlash through controlled engagement and elastic deformation, ensuring smooth torque transmission.
Implementation Method 1
a convex portion in the circumferential direction that protrudes in the axial direction and extends in the circumferential direction, and the other of the intermediate transmission member and one elastic member has a concave portion in the circumferential direction that opens in the axial direction and extends in the circumferential direction, and the convex portion in the circumferential direction contacts to at least one circumferential surface of both circumferential surfaces in the radial direction of an inner surface of the concave portions in the circumferential direction elastically
Data Source
AI summary
A torque transmission joint to suppress occurrence of noise when reversing the direction of rotation of a drive shaft. A first transmission member fixed to an output shaft (the drive shaft) is engaged with a first elastic member such that a first gap in a circumferential direction is interposed, as well as with an intermediate transmission member such that a larger gap in the circumferential direction is interposed. A second transmission member fixed to an end portion of a worm is engaged with a second elastic member such that a second gap in the circumferential direction is interposed, as well as with the intermediate transmission member such that a larger gap in the circumferential direction is interposed. First and second annular convex portions are fitted to, respectively, first and second concave portions to prevent separation of the first and second elastic members with respect to the intermediate transmission member.