Engine Intake Control Positioning Boss and Shaft
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Solution Overview
Problem
Conventional engine intake control apparatuses face challenges in maintaining accurate inter-shaft distance and proper backlash in the reduction gear row due to errors in the assembly process, leading to deteriorated opening and closing accuracy of the throttle valve.
Innovation Solution
The engine intake control apparatus features a cover made of synthetic resin with an integrally formed positioning boss, a metal motor support plate with positioning holes, and a positioning shaft that accurately defines the positional relationship between components, ensuring precise inter-shaft distance and backlash adjustment, while preventing motor short-circuiting and accommodating thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional assembly methods are used without special positioning structures, then assembly process is simple, but manufacturing precision of inter-shaft distance and backlash deteriorates
Solution Approach 1:
A positioning shaft is introduced as an intermediary component to establish precise spatial relationships between the cover, motor support plate, and throttle valve body. The positioning shaft features a positioning portion that fits into a positioning hole in the motor support plate, thereby mediating the positional alignment and ensuring accurate inter-shaft distance and backlash without requiring complex direct positioning structures between the three main components.
2Measurement precision
If conventional assembly methods are used without special positioning structures, then assembly process is simple, but opening and closing accuracy of throttle valve deteriorates
Solution Approach 1:
The positioning shaft serves as a mediator to transfer and maintain precise positional relationships from the cover through the motor support plate to the throttle valve body. By providing a fixed reference axis with the positioning portion, it ensures that the motor and throttle valve are accurately aligned, thereby improving throttle valve opening and closing accuracy without requiring complex adjustment mechanisms.
3Ease of manufacture
If cover is made of synthetic resin, then weight is reduced and manufacturing is easier, but positioning precision may deteriorate due to material flexibility
Solution Approach 1:
The positioning structure employs a composite approach where the cover is made of lightweight synthetic resin for ease of manufacture, while the positioning shaft and its positioning portion are made of rigid material to ensure precise positioning. This combination allows the cover to benefit from the advantages of synthetic resin (lightweight, easy to manufacture) while the rigid positioning components maintain the required positioning precision despite the flexible cover material.
Data Source
AI summary
In an engine intake control apparatus, a cover is made of synthetic resin, a motor support plate is made of metal, a positioning boss is integrally formed on the cover, a first positioning hole arranged on a motor support plate is fitted on an outer peripheral surface of the positioning boss, and the positioning boss is positioned and fitted with a throttle valve body each other. With such an engine intake control apparatus, it is possible to perform with high accuracy the mutual positioning between the three components, i.e. the motor support plate, the cover and the throttle valve body, and it is possible to effectively improve the opening and closing accuracy for the opening and closing of the throttle valve by the motor.