Spiral Spring Bent Part Resonance Control
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Solution Overview
Problem
Existing fluid-pressure-operated valve timing controllers face issues with endurance and responsivity due to resonance and excessive stress in the spiral spring, caused by increased engine vibration frequencies matching the natural frequency of the spiral spring, leading to potential failure and reduced valve timing responsiveness.
Innovation Solution
The design incorporates a spiral spring with a bent part that linearly contacts adjacent elements, increasing the primary natural frequency and reducing resonance, while eliminating unnecessary radial forces to enhance durability and responsivity, and optimizing the spiral spring's geometry to prevent excessive stress and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spiral spring is designed with a standard configuration, then the device structure is simple, but resonance occurs when engine vibration frequency matches the natural frequency of the spiral spring, causing excessive stress and potential failure
Solution Approach 1:
The patent applies local quality by introducing a bent part at a specific location along the spiral spring's element wire. This localized structural modification changes the stress distribution and natural frequency characteristics only in the critical region, rather than redesigning the entire spring. The bent part creates a geometric feature that alters vibration behavior and reduces resonance susceptibility, thereby improving reliability without significantly increasing overall device complexity.
2Stress or pressure
If the most outside circumference part of the element wire is brought inward in the radial direction to increase contact between wire parts, then the natural frequency of the spiral spring is reduced making resonance easier to generate, but this was intended to prevent excessive stress
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the spiral spring, specifically introducing a bent part with a predetermined curvature radius. This changes the physical dimensions and shape parameters of the spring, which in turn alters its natural frequency and stress distribution characteristics. The bent part creates a localized geometric parameter change that prevents excessive stress while avoiding the resonance issue caused by bringing the outside circumference part inward.
3Strength
If the most outside circumference part is brought inward at the contact position in the radial direction, then contact between wire parts increases, but the element wire may be tensioned outward at positions different from the contact position, generating excessive stress
Solution Approach 1:
The bent part creates a localized quality change that differentiates the contact mechanism from the tension mechanism. By introducing this geometric feature at a specific location, the patent ensures that contact between wire parts occurs through the bent part's geometry rather than through radial compression, thereby preventing unintended tension stresses at other positions along the element wire.
4Reliability
If unnecessary force is applied in the radial direction to the most inside circumference part supported by the inner rotor, then contact resistance between the inner rotor and outer rotor increases, lowering the responsivity of the valve timing
Solution Approach 1:
The patent applies the taking out principle by removing the harmful radial force component from the system. The bent part geometry is designed to redirect forces away from the inside circumference part, extracting the unnecessary radial force that was causing increased contact resistance. This allows the inside circumference part to interact with the inner rotor primarily through axial forces, maintaining low contact resistance and high responsivity.
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 significantly improves the endurance and responsivity of the valve timing controller by preventing resonance and excessive stress, reducing torque loss, and maintaining high durability and responsiveness.
Implementation Method 1
The spiral spring is constructed by an element wire spirally extending. The element wire has a most outer circumference part supported by the outer rotor at a first position and a most inner circumference part supported by the inner rotor at a second position. The circumference direction has a deformation direction and a biasing direction opposite from each other. The spiral spring biases the inner rotor in the biasing direction relative to the outer rotor by twistingly deforming in accordance with rotation of the inner rotor in the deformation direction relative to the outer rotor.
Implementation Method 2
If the frequency of vibrations is increased to be equal to a natural frequency of vibration of the spiral spring, resonance will occur in the spiral spring. As a result, stress applied to the spiral spring is rapidly increased, and the spiral spring may have a failure such as bending or crack. The spiral spring has a bent part bent to protrude in a radial direction between the first position and the second position, and the bent part of the spiral spring is linearly contact with a part of the element wire located adjacent to the bent part in the radial direction.
Data Source
AI summary
A fluid-pressure-operated valve timing controller includes an outer rotor, an inner rotor, and a spiral spring constructed by an element wire spirally extending. The spiral spring biases the inner rotor in a biasing direction when the spiral spring twistingly deforms in accordance with sliding rotation of the inner rotor in a deformation direction relative to the outer rotor. The spiral spring has a bent part bent to protrude in a radial direction. The bent part of the spiral spring is linearly contact with a part of the element wire located adjacent to the bent part in the radial direction.