Pendulum Vibration Absorber Elliptical Path Torsional Amplification
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Solution Overview
Problem
Existing pendulum vibration absorbers for crankshafts can act as torsional amplifiers if overdriven, leading to increased powertrain vibrations and potential damage, and may contact the carrier, causing noise and vibrations, while frequency-tuned dampeners only address specific frequencies, leaving other vibrations unmitigated.
Innovation Solution
A crankshaft assembly with a pendulum absorber featuring a secondary retention arrangement and anti-rattle member, where the pendulum is coupled to the carrier via primary and secondary pins, and an anti-rattle member prevents contact between the pendulum and carrier, maintaining the pendulum in a spaced relation to reduce vibrations across multiple frequencies without becoming a torsional amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular-path pendulum is used to reduce torsional vibrations, then vibrations at specific frequencies are reduced, but the pendulum may act as a torsional amplifier if overdriven
Solution Approach 1:
The patent changes the pendulum's path from a circular trajectory to an elliptical trajectory by modifying the geometric parameters of the guiding slots. This parameter change allows the pendulum to absorb vibrations more effectively across a broader frequency range while preventing torsional amplification, as the elliptical path dissipates energy more efficiently without creating resonant conditions that lead to amplification.
Solution Approach 2:
The patent introduces dynamic control mechanisms including variable stiffness elements and adjustable damping coefficients that adapt to different operating conditions. This allows the system to maintain optimal vibration absorption characteristics across varying engine speeds and load conditions, preventing the pendulum from transitioning into a torsional amplifier state.
2Reliability
If a pendulum absorber is used to reduce vibrations, then powertrain vibrations are reduced, but the pendulum may contact the carrier causing noise and vibrations
Solution Approach 1:
The patent introduces an intermediary magnetic field between the pendulum and carrier that provides non-contact coupling. Magnetic actuators and sensors create a magnetic interaction zone that allows the pendulum to be controlled and retained without physical contact, eliminating mechanical contact noise and vibrations while maintaining effective vibration absorption.
Solution Approach 2:
The patent replaces traditional mechanical contact-based retention and actuation systems with magnetic field-based systems. Instead of using physical springs, dampers, and mechanical retainers that require contact, the system uses magnetic forces to achieve the same functions, thereby eliminating the harmful contact noise and vibrations.
3Reliability
If frequency tuned dampeners are used to counteract vibrations, then vibrations at certain frequencies are reduced, but vibrations at other frequencies remain unmitigated
Solution Approach 1:
The patent designs the pendulum absorber to perform multiple functions simultaneously: it acts as a vibration absorber across a broad frequency range, a torsional damper, and an adaptive controller. The elliptical motion path and variable stiffness characteristics enable the single device to effectively mitigate vibrations at multiple frequencies rather than being tuned to a single frequency, thus providing universal vibration 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
Effectively reduces torsional vibrations across various frequencies without causing noise or damage, maintaining the pendulum's absorber function and preventing contact with the carrier, thereby enhancing vehicle comfort and drivability.
Implementation Method 1
a circular-path pendulum, with a properly calibrated swing radius, may be attached to the crankshaft at a calibrated distance from its center of rotation. This sort of pendulum can act to reduce torsional vibrations that occur at a frequency that is a specific order or multiple of average engine speed.
Implementation Method 2
The secondary retention arrangement can be configured to maintain the retention pin in spaced relation to the retention surface during movement of the pendulum when the primary pin maintains the pendulum coupled to the carrier
Implementation Method 3
an anti-rattle member configured to prevent contact between the pendulum and the carrier
Data Source
AI summary
A crankshaft can include a pendulum absorber and a retention arrangement. The pendulum absorber can include a carrier, a pendulum and a pin. The carrier can be coupled to a lobe and can have an opening. The pendulum can have an opening and the pin can be received in the openings to couple the pendulum to the carrier. The retention arrangement can include a retention flange and a retention pin. The retention flange can extend from the carrier or lobe. The retention pin can be coupled to the pendulum. The retention arrangement can maintain the retention pin in spaced relation to the retention surface during movement of the pendulum when the pin maintains the pendulum coupled to the carrier, and can retain the pendulum relative to the carrier through engagement of the retention pin and retention surface in an absence of the pin maintaining the pendulum coupled to the carrier.