Chain Tensioner Oil Leak Path for Temperature-Stable Damping

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Solution Overview

Problem

Conventional chain tensioners face challenges in dynamically adjusting flow path resistance to accommodate changes in oil viscosity due to temperature variations, leading to potential noise, vibration, and increased manufacturing costs.

Innovation Solution

A chain tensioner with an oil leak path containing a movable piece that deforms with temperature changes, adjusting flow path resistance to maintain consistent damping characteristics without the need for electric control systems, allowing for simpler configuration and reduced costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flow path resistance is manually or automatically adjusted to accommodate oil viscosity changes, then damping characteristics can be maintained, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvedamping characteristics consistencyVSAvoiddevice configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the physical state of the deformation member from rigid to flexible, allowing it to automatically adjust its position based on oil temperature-induced pressure changes. This passive parameter adjustment maintains damping characteristics without requiring complex control systems

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The deformation member automatically adjusts the opening degree of the oil leak path based on oil temperature and pressure conditions, eliminating the need for external control systems. The system serves itself by using the oil's own thermal expansion properties to regulate flow resistance

Inventive Principle:

Principle #25Self-service

2Reliability

If electric control systems are used to dynamically adjust flow path resistance, then damping characteristics can be maintained across temperature variations, but manufacturing cost increases

Engineering Contradiction:

Improvedamping characteristics consistencyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces electric control systems with a purely mechanical solution using a flexible deformation member that responds to oil pressure changes. This mechanical substitution eliminates sensors, controllers, and power systems while maintaining automatic adjustment capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The deformation member's flexibility parameter allows it to passively respond to oil temperature-induced pressure changes, automatically regulating oil leak flow resistance without requiring active control systems or increasing manufacturing complexity

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If fixed flow path resistance is used in the oil leak path, then device configuration is simple, but damping characteristics change with oil temperature

Engineering Contradiction:

Improvedevice configurationVSAvoiddamping characteristics consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent transforms the static oil leak path into a dynamic one by introducing a flexible deformation member that automatically adjusts the opening degree based on oil pressure. This dynamic adjustment maintains consistent damping characteristics across varying operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The flexible deformation member changes its position parameter in response to oil temperature-induced pressure changes, thereby dynamically adjusting the oil leak path resistance to maintain consistent damping characteristics

Inventive Principle:

Principle #35Parameter changes

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 solution effectively stabilizes damping characteristics across varying oil temperatures, simplifies device configuration, and reduces manufacturing costs by automatically adjusting flow path resistance through temperature-dependent deformation members.

Implementation Method 1

a movable piece 133 which is movable with a temperature-dependent deformation member 131 that deforms according to oil temperature

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the oil flows through the slight gap between the plunger 520 and the plunger accommodation hole 511 as the plunger 520 reciprocates, and the oil produces a flow path resistance to cause a damping effect

Methodology Applied

Scientific EffectViscous damping: Viscous Damping

Data Source

PatentUS11156272B2Chain tensioner

Publication Date: 2021.10.26 TSUBAKIMOTO CHAIN CO

AI summary

The present invention provides a chain tensioner that automatically adjusts flow path resistance inside an oil leak path with a simple configuration to make it possible to reduce a change in damping characteristics resulting from a change in oil temperature and reduce an increase in manufacturing cost. In the chain tensioner, a pressure oil chamber is provided with an oil leak path communicating with an outside of the chain tensioner, the oil leak path contains a movable piece which is movable with a temperature-dependent deformation member that deforms according to oil temperature, and the movable piece is formed into a shape that changes flow path resistance of the oil leak path according to a position to which the movable piece is moved.