Throttle Valve Spring Guide Structure for Low-Hysteresis Rotation
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Solution Overview
Problem
Existing throttle valve devices face challenges in accurately controlling rotation due to high sliding resistance from resin-made guides interacting with the body and valve gear, making precise control across the valve intermediate open position difficult.
Innovation Solution
The throttle valve device incorporates a design with guides that reduce contact area and sliding resistance by using guides with specific shapes and configurations, such as tapered hubs and connecting portions, and forming a T- or L-shape in cross-section, which minimizes contact with the lever and bearings, and includes a disc-shaped connecting portion with radial ribs for increased strength and reduced sliding resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin-made guides are used to support the coil spring, then the device structure is simplified and ease of manufacture is improved, but sliding resistance increases and measurement precision deteriorates
Solution Approach 1:
The guide structure is changed from a simple cylindrical shape to a tapered shape with specific dimensional parameters (larger diameter at one end, smaller at the other). This parameter change reduces the contact area between the guide and rotating components, thereby reducing sliding resistance and improving rotation control precision while maintaining the resin material's manufacturing advantages
Solution Approach 2:
The guide is designed with a tapered geometry that creates a wedge effect, utilizing the dimensional transition from uniform cylinder to tapered form. This dimensional change allows the guide to maintain stability while reducing contact area and sliding resistance during rotation
2Stability of the object's composition
If the guide contacts both the lever and bearing during rotation, then structural stability is improved, but sliding resistance increases and device complexity worsens
Solution Approach 1:
The guide structure is designed to contact only one component (either the lever or the bearing) at a time during rotation, rather than both simultaneously. This extraction of one contact function reduces sliding resistance and simplifies the device while maintaining sufficient structural stability through the tapered geometry and proper positioning
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
This design significantly reduces hysteresis and sliding resistance, allowing for more precise control of the throttle valve, enabling accurate rotation across the valve intermediate open position and contributing to a downsized device with reduced assembly time and costs.
Implementation Method 1
The coil spring applies a biasing force when the rotation of the motor is transmitted to the shaft
Implementation Method 2
The first guide is in contact with the lever only at an end surface of the hub when the at least one of the first guide and the second guide is the first guide. The second guide is in contact with one of the pair of bearings, which is located close to the valve gear, at an end surface of the hub
Data Source
AI summary
A throttle valve device includes a body, a shaft, a pair of bearings, a valve, a motor, a valve gear, a coil spring, a first guide, and a second guide. At least one of the first guide and the second guide includes a circular holder that faces an end surface of the coil spring, a spring-end holding portion that outwardly protrudes from the circular holder and is configured to hold a spring end of the coil spring, a hub that is rotatably connected to the shaft, and a connecting portion that connects the hub and the circular holder. The first guide is in contact with a lever only at an end surface of the hub. The second guide is in contact with one of the pair of bearings, which is located close to the valve gear, at an end surface of the hub.