Valve Timing Spiral Spring Wear Reduction via Elastic Clip
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Solution Overview
Problem
The existing valve timing adjustment devices experience wear between the spiral spring and stopper pins due to line contact, leading to potential breakage of the spiral spring.
Innovation Solution
A valve timing adjustment device with a clip attached to a projection on the first rotary body, which comes into contact with the outermost winding of the spiral spring instead of the stopper pins, reducing wear by utilizing an elastic force to minimize direct contact and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stopper pins are used to stop radially outward expansion of the spiral spring, then the spiral spring can be prevented from breaking, but wear occurs between the spiral spring and stopper pins due to line contact
Solution Approach 1:
A clip is introduced as an intermediary component between the spiral spring and the projection. The clip contacts the outermost winding of the spiral spring with its first portion, while being attached to the projection by elastic force. This mediator transfers the stopping function from direct projection-spring contact to clip-spring contact, reducing wear on both the spiral spring and projection while maintaining the expansion stopping function
2Device complexity
If the projection directly contacts the spiral spring to stop expansion, then the structure is simple, but wear and torque loss occur due to direct line contact
Solution Approach 1:
The clip serves as a minimal added intermediary that interfaces between the projection and spiral spring. The first portion of the clip contacts the outermost winding of the spiral spring, distributing contact forces and reducing wear compared to direct projection-spring line contact, while the clip remains attached to the projection through elastic force
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 clip reduces wear on both the spiral spring and the projection, thereby preventing torque loss and breakage of the spiral spring, while maintaining effective biasing and adjustment functionality.
Implementation Method 1
a clip (6) having a first portion (6a) coming in contact with the outermost winding (5c) of the spiral spring, the clip being attached to the projection (13) by elastic force of the clip
Data Source
AI summary
A spiral spring (5) has an inner circumferential end (5a) fixed to a rotor (3) and an outer circumferential end (5b) fixed to a plate (8) of a housing (2), and biases the rotor (3) in one direction with respect to the housing (2). A projection (13) protrudes from the plate (8), and stops radially outward expansion of an outermost winding (5c) of the spiral spring (5). A clip (6) has a first portion (6a) coming in contact with the outermost winding (5c) of the spiral spring (5), and is attached to the projection (13) by elastic force of the clip (6).