CVT Parking Gear Shielding With Auxiliary Rib Structure
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Solution Overview
Problem
Existing continuously variable transmissions (CVTs) cannot completely prevent foreign matters such as metal belt fragments from scattering towards the parking gear, leading to potential damage and failure.
Innovation Solution
A CVT design that includes a guide support and an auxiliary rib extending from the guide support, with a gap from the drive pulley equal to or smaller than a predetermined width, to prevent foreign matters from scattering towards the parking gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover member is used to protect the parking gear, then foreign matters can be blocked, but foreign matters such as metal belt fragments can still scatter toward the parking gear
Solution Approach 1:
The patent introduces a guide support structure that extends in the axial direction of the drive pulley, creating a three-dimensional barrier system. This axial extension blocks foreign matters from scattering toward the parking gear in the axial dimension, complementing the radial protection provided by the cover member, thereby achieving comprehensive multi-directional protection.
Solution Approach 2:
The guide support acts as an intermediary structure between the drive pulley and the parking gear. It intercepts and redirects foreign matters (such as broken metal belt fragments) before they can reach the parking gear, serving as a protective mediator that prevents direct contact between harmful particles and the vulnerable parking gear components.
2Reliability
If the gap between the auxiliary rib and drive pulley is reduced, then foreign matter intrusion is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a preventive approach by providing the guide support and auxiliary rib structures that create multiple barriers against foreign matter intrusion. Rather than relying solely on achieving a precisely small gap, the design uses the geometric configuration of extended support surfaces to block foreign matters at multiple points, providing excessive protection that compensates for normal manufacturing tolerances.
Data Source
AI summary
A continuously variable transmission includes, in a case: a drive pulley and a driven pulley each including a fixed-side pulley half and a movable-side pulley half configured to move axially relative to the fixed-side pulley half; a belt including a plurality of elements and a plurality of rings wound around the drive pulley and the driven pulley; a parking gear provided to the fixed-side pulley half of the driven pulley; a parking pawl configured to be fitted to the parking gear; a parking rod configured to swing the parking pawl; and a guide member configured to guide the parking rod, the continuously variable transmission transmitting a driving force a wheel while changing a transmission ratio by changing groove widths of the drive pulley and the driven pulley, wherein the case includes an auxiliary rib having a gap from the drive pulley equal to or smaller than a predetermined width.