CVT Key Damping Member for Noise Reduction
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Solution Overview
Problem
Conventional CVTs experience noise issues due to key vibration and contact with supporting members, leading to wear and reduced durability.
Innovation Solution
A CVT design featuring a damping member with an axial length greater than the key, positioned between the key and supporting member, allowing axial movement and alleviating collision impact, thereby reducing noise and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a key is used to couple the movable sheave half to the crankshaft, then the movable sheave half can be rotatably driven while being axially movable, but the key may run wild in the keyway and holding groove due to crankshaft vibration, causing noise
Solution Approach 1:
A damping member is introduced as an intermediary element between the key and the supporting member. This damping member absorbs the impact when the key runs wild due to crankshaft vibration, preventing direct collision between the key and supporting member, thereby eliminating noise while maintaining the axial movability function of the key-coupled movable sheave half.
Solution Approach 2:
The damping member is pre-installed in the damping chamber of the supporting member to provide cushioning protection before any collision occurs. This beforehand cushioning ensures that when the key runs wild during operation, the impact is already mitigated by the damping material, preventing noise and potential damage.
2Stability of the object's composition
If the key is allowed to move freely in the keyway to accommodate crankshaft deflection, then the coupling remains effective under elastic deflection, but the key may collide with the supporting member causing wear and reduced durability
Solution Approach 1:
The damping member is pre-positioned in the damping chamber to provide protective cushioning before any harmful collision occurs. This allows the key to move freely within the keyway to accommodate crankshaft deflection while the damping member stands ready to absorb any impact, preventing wear and extending the durability of both the key and supporting member.
Solution Approach 2:
The damping member serves as a protective intermediary between the key and the supporting member structure. It allows the key to maintain its free movement capability for accommodating deflection while mediating any potential collision through energy absorption, thereby preserving the reliability and durability of the entire coupling system.
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 CVT effectively restricts noise caused by key contact and enhances the durability of the damping member by distributing contact points, reducing wear and improving sound absorption.
Implementation Method 1
a damping member disposed between an outer face of the key and an inside face of the supporting member and adapted to move axially relative to the key
Data Source
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AI summary
A continuously variable transmission (10) comprises a primary sheave (31) which includes a fixed sheave half (34) fixed to a crankshaft (11); and a movable sheave half (35), having a boss portion (38) covering the outside round surface of the crankshaft (11) and with a keyway (40) extending in the axial direction of the crankshaft (11), and freely movable in the axial direction of the crankshaft (11). A key (42) rotating together with the crankshaft (11) for transmitting torque of the crankshaft (11) to the boss portion (38) is inserted for free sliding in the keyway (40). A supporting member (43) of a generally cylindrical shape for covering the keyway (40) is provided around the boss portion (38). A damping member (81) capable of making relative axial motion is interposed between the top face (42a) of the key (42) and the inside round surface of the supporting member (43).