Eccentric-Web Bearing Bush for Progressive Torsional Stiffness
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Solution Overview
Problem
Existing bearing bushes with radially extending webs primarily induce shear stresses, leading to inadequate torsional stiffness and resonance issues due to their natural frequency alignment with vehicle part excitation frequencies, and fail to achieve reliable centering and progressive stiffness.
Innovation Solution
A bearing bush design featuring an elastomer body with at least four webs whose longitudinal centerlines are arranged eccentrically, not directed towards the central axis, inducing compressive stresses and allowing for self-centering and progressive stiffness adjustment through angled web configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radially extending webs are used in the elastomer body, then the bearing bush provides structural support and damping, but primarily shear stresses are induced which prevent good calibration and reliable centering
Solution Approach 1:
The patent applies asymmetry by arranging the longitudinal centerlines of the webs eccentrically rather than radially symmetrically. Specifically, the centerlines are directed at angles relative to the radius such that they do not all meet at a common central point, creating an asymmetric stress distribution that induces compressive stresses in addition to shear stresses, thereby enabling reliable centering and calibration
2Ease of operation
If radially extending webs are used in the elastomer body, then the bearing bush provides torsional flexibility, but the torsional stiffness does not progress adequately with increasing deflection
Solution Approach 1:
The patent changes the geometric parameters of the web arrangement by directing their longitudinal centerlines at specific angles relative to the radius (eccentrically). This parameter change transforms the stress state in the elastomer during torsional movement, inducing compressive stresses that contribute to progressive stiffness while maintaining initial flexibility, thus resolving the contradiction between torsional flexibility and stiffness progression
3Loss of energy
If the bearing bush has a natural frequency aligned with vehicle part excitation frequencies, then the bearing bush provides effective vibration damping, but resonance occurs leading to undesirably large amplitudes
Solution Approach 1:
The patent applies dynamics by creating a bearing bush with progressive stiffness characteristics through the eccentric web arrangement. The natural frequency of the bearing bush can adapt as the stiffness changes with deflection, allowing the system to maintain effective damping across varying operating conditions while avoiding sustained resonance at fixed frequencies, thus resolving the contradiction between vibration damping and resonance control
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 bearing bush ensures reliable centering, increased torsional flexibility, and improved stiffness progression, reducing resonance and enhancing the capacity to handle radial movements and loads effectively.
Implementation Method 1
an elastomer body (4) which is arranged between the core (2) and the outer sleeve (3). The elastomer body (4) comprises at least four webs (5a-d). The longitudinal centerlines (M1-4) of the at least four webs (5a-d) are not directed toward the central longitudinal axis (Z) of the bearing bush (1). Instead, the longitudinal centerlines (M1-4) are directed eccentrically
Implementation Method 2
vehicle parts, such as, for example, internal combustion engines, electric motors or transmissions, can be attached to the body in a damping manner, thereby making it possible to isolate the vibrations generated by the respective vehicle part
Data Source
AI summary
The invention involves a bearing bush for supporting a vehicle part on a vehicle body. In embodiments, a bearing bush includes a core, which extends along a central longitudinal axis of the bearing bush, and an outer sleeve, which surrounds the core circumferentially. In embodiments, an elastomer body is arranged between the core and the outer sleeve; the elastomer body comprises at least four webs, each having a centerline; and/or longitudinal centerlines of the at least four webs are not directed toward the central longitudinal axis of the bearing bush.