Chain Tensioner Securing Mechanism for Engine Assembly
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Solution Overview
Problem
The existing chain tensioner for internal combustion engines faces challenges in assembly workability due to misalignment issues when the tensioner member is biased by a spring, leading to difficulties in securing the chain tensioner to the engine case body.
Innovation Solution
The proposed chain tensioner design includes a securing member with an upper securing portion secured to the engine main body in the bending direction of the tensioner member and a lower securing portion positioned perpendicularly to the bending direction, allowing for turnable support and preventing misalignment, enabling easier assembly and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tensioner member is biased by a spring and shifted in the biasing direction, then the chain tensioner applies tensile force to the endless chain, but the attachment holes of the case body and secured member become misaligned, making assembly difficult
Solution Approach 1:
The securing member is divided into two separate securing portions: an upper securing portion that secures the chain tensioner to the case body in the bending direction of the tensioner member, and a lower securing portion that secures it perpendicularly to the bending direction. This segmentation allows each portion to be secured independently, preventing misalignment issues during assembly while maintaining the spring biasing function for chain tension.
2Manufacturing precision
If the securing member is secured to the case body with both attachment holes aligned, then the chain tensioner is properly positioned, but the spring biasing force causes misalignment between attachment holes during assembly
Solution Approach 1:
The lower securing portion is designed to be secured first in a direction perpendicular to the bending direction, establishing a stable baseline position that is not affected by spring biasing. Then the upper securing portion is secured in the bending direction. This preliminary action of securing the lower portion first prevents misalignment issues during the overall assembly process.
3Adaptability or versatility
If the lower securing portion is positioned to allow turnable support, then the tensioner member can be adjusted and is not obstructive, but the securing member length increases
Solution Approach 1:
The lower securing portion is positioned at a location that allows the tensioner member to be turned about an axis perpendicular to the bending direction. This dimensional change in securing orientation enables the tensioner to be adjusted to different angular positions and prevents obstruction, while the securing member length is optimized by strategically positioning the lower securing portion to minimize the required length.
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 enhances assembly workability by preventing misalignment and allowing for adjustable positioning of the chain tensioner, reducing the length and weight of the securing member, and facilitating the removal of the chain tensioner by providing a tool-accessible hole for spring disengagement.
Implementation Method 1
a tensioner member provided to straddle between the securing member and the movable member, the tensioner member being elastically deformed and arcuately bent by the movable member biased and displaced in the biasing direction thereof
Data Source
AI summary
A chain tensioner includes a base frame secured to each of front and rear banks, a slider plate shiftable in the extending direction of the base frame, and a tensioner provided to straddle between the base frame and the slider plate. The slider plate is biased to elastically deform and arcuately bend the tensioner, which applies a tensile force to each of cam chains transmitting the rotation of a crankshaft. In the chain tensioner, upper securing portions are provided in an upper portion of the base frame so as to be secured to each of the front and rear banks in the bending direction of the tensioner. A lower end of the base frame extends to a position facing the inside of the crankcase to provide a lower securing portion which is secured to each of the front and rear banks perpendicularly to the bending direction of the tensioner.