Tensioner Check Valve Retention via Segmented Coil Spring
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Solution Overview
Problem
The existing tensioner designs face issues with reduced maintenance efficiency due to the check valve tipping or falling out during plunger removal, compromised sealing performance due to radial gaps, and limited design freedom for the check valve, as well as potential coil spring deformation during assembly.
Innovation Solution
A tensioner design featuring a coil spring with a small-diameter and large-diameter part, where the large-diameter part is larger than the valve setting hole, allowing it to be radially compressed and retaining the check valve, preventing it from tipping or falling out and ensuring proper sealing, while also preventing the coil spring from getting caught on the check valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the check valve is retained at a predetermined position by the pressing force of the coil spring, then the check valve can be positioned during operation, but the check valve may tip inside the plunger hole or fall out when the plunger is removed for maintenance
Solution Approach 1:
The coil spring is divided into two functional parts: a small-diameter part for normal operation and a large-diameter part for maintenance. The large-diameter part can be radially compressed to reduce its diameter, allowing it to pass through the valve setting hole during assembly and then expand to retain the check valve during operation, preventing it from tipping or falling out during maintenance
Solution Approach 2:
The coil spring transitions from a static retention mechanism to a dynamic one where the spring's diameter can change. The large-diameter part is designed to be radially compressed during assembly to fit through the valve setting hole, then naturally expands to its original larger diameter to provide retention force, adapting its state based on operational requirements
2Reliability
If the check valve is pressed by the coil spring against the stepped portion to provide sealing, then sealing is achieved, but radial gaps cause the check valve to displace radially and deteriorate sealing performance
Solution Approach 1:
The coil spring's diameter parameter is dynamically changed through radial compression of the large-diameter part. This allows the spring to adapt its dimensions to eliminate radial gaps between the check valve and valve setting hole, ensuring uniform contact between the seat member and stepped portion for reliable sealing
3Ease of manufacture
If the check valve is designed to prevent coil spring distal end from getting caught, then assembly failure is avoided, but the degree of design freedom of the check valve is limited
Solution Approach 1:
The coil spring is segmented into small-diameter and large-diameter parts with distinct functions. The large-diameter part's ability to be radially compressed creates sufficient clearance during assembly, preventing the distal end from getting caught on the check valve, while the overall spring structure remains flexible enough to accommodate various check valve designs without limiting design freedom
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 maintenance efficiency, prevents check valve loss, maintains effective sealing, and increases design freedom by ensuring the check valve is centered and securely positioned, facilitating easier assembly and operation.
Implementation Method 1
a coil spring accommodated inside an oil pressure chamber formed between the plunger and the plunger accommodating hole so as to be able to expand and contract and to urge the plunger toward a front side
Implementation Method 2
The largest diameter in the large-diameter part in a portion that is disposed inside the valve setting is set larger than an inner diameter of the valve setting hole
Data Source
AI summary
To provide a tensioner that improves, with a simple structure, maintenance operation efficiency, as well as enhances the sealing performance and the degree of freedom of check valve design. Either a plunger or a housing has a valve setting hole for disposing a check valve therein, and a valve movement restricting part that restricts movement of the check valve, disposed in the valve setting hole, toward an oil supply passage. A coil spring includes a small-diameter part and a large-diameter part continuous with the small-diameter part and disposed in contact with the check valve. The coil spring is disposed so as to urge the check valve toward the oil supply passage. The largest diameter of the large-diameter part is set larger than the inner diameter of the valve setting hole.