Engine Cover Integral Molding Attachment Member
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Solution Overview
Problem
Conventional engine covers have high manufacturing costs due to multiple processing steps and are prone to grommet detachment issues during maintenance, with burrs formed during foam molding affecting dimensional accuracy and sound transmission.
Innovation Solution
The engine cover integrates the attachment member with the cover body through integral molding, using a thermoplastic urethane elastomer attachment member with a sealing portion and reinforcement rib to enhance adhesion and reduce burrs, and a thinning portion to improve detachment ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grommet is attached to an attachment base to manufacture an engine cover, then the attachment function is achieved, but the number of processing steps increases and manufacturing cost increases
Solution Approach 1:
The attachment member is integrated into the cover body through integral molding, combining two separate components (attachment member and cover body) into a single molded part. This eliminates the need for separate attachment processes and reduces the number of processing steps while maintaining the attachment function.
2Reliability
If a grommet is attached to an attachment base, then the attachment function is achieved, but the grommet may be incidentally removed during maintenance and needs to be reattached
Solution Approach 1:
By integrating the attachment member into the cover body through integral molding, the attachment member becomes an inherent part of the cover body structure. This prevents accidental removal during maintenance and eliminates the need for reattachment, as the attachment member cannot be separated from the cover body without damaging the molded structure.
3Ease of manufacture
If foam molding is performed for a foamable resin material to cover the attachment member, then the cover body is formed, but burrs are formed on the periphery of the recess opening due to foaming pressure
Solution Approach 1:
A projection is provided on the attachment member that protrudes from the opening of the recess. This projection acts as a preliminary barrier to prevent the foaming resin material from entering the recess during foam molding. By addressing the potential burr formation issue before molding occurs, the need for post-molding burr removal is eliminated, and dimensional accuracy is maintained.
4Strength
If the covering material is made of polypropylene or polyamide which are full hard, then the structural strength is achieved, but vibrations from the engine are easily transmitted and secondary sound is generated
Solution Approach 1:
The cover body is constructed using a composite structure combining a skin layer made of hard resin (polypropylene or polyamide) for structural strength, and a sound absorption layer made of foamed resin for vibration damping and sound absorption. This composite material approach allows the cover body to simultaneously achieve structural strength and reduce sound transmission.
5Device complexity
If an attachment member with a recess is disposed in the sound absorption layer through foam molding, then the attachment function is integrated, but the formable resin material easily enters the recess due to foaming pressure
Solution Approach 1:
A projection is provided on the attachment member that protrudes from the opening of the recess. This projection serves as a preliminary barrier to prevent the foaming resin material from entering the recess during foam molding. By addressing the potential material entry issue before molding occurs, the dimensional accuracy at the recess opening is maintained, and burr formation is prevented.
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 approach reduces manufacturing costs, improves sound absorption, and ensures secure attachment without burrs, maintaining dimensional accuracy and preventing attachment defects.
Implementation Method 1
the attachment member is formed of an elastic body, whereby vibrations generated from an engine can be absorbed by the attachment member and the cover body
Data Source
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AI summary
The present invention provides an engine cover that can be manufactured easily and at a lower cost and has an attachment member that is high in quality and may not easily fall off. The engine cover (1) has a cover body (2) made of urethane foam, a skin layer (3) disposed on a surface of the cover body (2), and an attachment member (4) made of an elastic body and integrally molded with the cover body (2). The attachment member (4) has a recess (40) into which an attachment pin (81) provided to project from an engine member (80) is fitted, and a sealing portion (41) that is provided to project at least one of the opening end surface (430) of the recess (40) and the side surface of the opening end part (431) of the recess (40) and that suppresses entry of a foamed urethane resin material (20) that forms the cover body (2) into the recess (40) during integral molding.