Filter Casing Anti-Loosening Leaf Spring Mechanism

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Solution Overview

Problem

Existing element replacement type filters face challenges in minimizing the radial dimension of the casing while ensuring a strong, durable, and cost-effective anti-loosening mechanism, as previous designs either compromise on strength and durability or increase the casing size due to complex structures and increased parts.

Innovation Solution

The filter employs a metal leaf spring member that is elastically deformable in the radial direction, with a regulating portion on the outer peripheral side of one casing member and a contact portion with specific angled surfaces to facilitate easy tightening and difficult loosening, along with a press-fixed portion for easy attachment and vibration suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ring-shaped leaf spring that elastically deforms in the axial center direction is provided on the inner peripheral side of the case, then the anti-loosening mechanism is provided within the casing, but the dimension in the radial direction of the casing increases

Engineering Contradiction:
Improveanti-loosening mechanism reliabilityVSAvoidradial dimension of casing
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent inverts the conventional design by placing the leaf spring on the outer peripheral side of the case rather than the inner peripheral side, and making it elastically deform in the radial direction rather than the axial direction. This inversion allows the anti-loosening mechanism to function effectively while minimizing the radial dimension of the casing.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the dimension of elastic deformation from the axial direction to the radial direction. By making the leaf spring elastically deform in the radial direction rather than the axial center direction, the design achieves compact radial dimensions while maintaining anti-loosening functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a mobile pin biased by a coil spring and projecting portion structure is used, then the anti-loosening mechanism is formed, but the structure becomes complicated and expensive with at least three parts

Engineering Contradiction:
Improveanti-loosening mechanism reliabilityVSAvoidnumber of parts in anti-loosening mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of the mobile pin, coil spring, and projecting portion into a single integrated leaf spring member. This consolidation reduces the number of parts from three separate components to one unified structure, simplifying the anti-loosening mechanism while maintaining its reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leaf spring member performs multiple functions simultaneously: it provides elastic deformation for engagement, acts as the anti-loosening element, and replaces the need for separate mobile pin and coil spring components. This multi-functionality reduces part count and complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If the leaf spring member is provided on the outer peripheral side of the case, then the radial dimension is minimized, but it may be damaged from contact with tools and attachment/removal under cold conditions

Engineering Contradiction:
Improveradial dimension of casingVSAvoidleaf spring member strength
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The patent changes the material parameter from synthetic resin to metal for the leaf spring member. This material substitution significantly increases strength and durability, enabling the leaf spring to withstand contact with tools and attachment/removal operations under cold conditions while maintaining the compact radial dimension design.

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

This design achieves a compact structure with high strength and durability, preventing damage from cold conditions and allowing for easy maintenance, while minimizing the radial casing dimension and enhancing reliability by positioning the leaf spring member externally for easier defect detection.

Implementation Method 1

a leaf spring member made of metal that is provided elastically deformable in a radial direction of the second casing member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1772177B1Element replacement type filter
Publication Date: 2009.10.14 TOYOTA BOSHOKU KK
  • EP1772177B1 patent drawingFigure 1
  • EP1772177B1 patent drawingFigure 2~3
  • EP1772177B1 patent drawingFigure 4~6

AI summary

An element replacement type filter accommodates an element assembly that includes a filter element (1) within a casing formed from a first casing member (2) and a second casing member (3) which are mutually screwable by relative rotation, and provides an anti-loosening mechanism (30) between the first casing member (2) and the second casing member (3). The anti-loosening mechanism (30) comprises a regulating portion (31) that is provided on an outer peripheral side of the first casing member (2); and a leaf spring member (32) made of metal that is provided elastically deformable in a radial direction of the second casing member (3), with a base end side (37) thereof fixed to an outer peripheral side of the second casing member (3). The leaf spring member (32) has a free end side that is provided with a contact portion (35), which contacts the regulating portion (31) due to relative rotation of the first casing member (2) and the second casing member (5).