Resin Cylindrical Member with Slit for Input Device Locking

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Solution Overview

Problem

The existing input devices, such as those described in Japanese Patent Application Laid-Open No. 2007-99058, require costly machining processes to ensure the swingability of the input rod's head part within the piston, leading to increased production time and costs.

Innovation Solution

An input device featuring a cylindrical member made of resin with a rod receiving part, a locking part, and a slit along its axial direction, allowing for elastic deformation and eliminating the need for swaging processes, thereby simplifying assembly and reducing costs while enhancing locking and holding capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston end part is swaged to hold the input rod head part swingably, then the input rod can be securely locked in the piston, but the machining process becomes complex and time-consuming, increasing production cost

Engineering Contradiction:
Improvelocking reliabilityVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the expensive and time-consuming swaging process with a disposable resin cylindrical member that is molded with integrated locking features. This resin component is designed to be assembled once and discarded if needed, eliminating the need for complex machining while maintaining secure locking of the input rod in the piston.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses composite construction by integrating multiple functions into a single resin cylindrical member that combines the rod receiving part, locking part, and elastic deformation capability. This composite approach replaces traditional metal swaging processes with a molded resin solution that achieves the same locking function more efficiently.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the piston end part is swaged to secure the input rod, then locking is achieved, but the number of machining processes increases, resulting in higher cost

Engineering Contradiction:
Improvelocking functionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the rod receiving function, locking function, and elastic deformation capability into a single resin cylindrical member. This integration eliminates the need for separate swaging operations and multiple components, simplifying the manufacturing process while maintaining reliable locking of the input rod in the piston.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resin cylindrical member is designed as a cost-effective, molded component that replaces expensive and complex swaging processes. It is manufactured once with all necessary features integrated, reducing both manufacturing complexity and cost while achieving the required locking reliability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If a resin cylindrical member with a slit is used to replace swaging, then productivity improves and cost reduces, but the member must withstand lateral forces that try to dislodge the input rod

Engineering Contradiction:
Improveassembly efficiencyVSAvoidwithstand load capacity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent changes the physical state and properties of the cylindrical member by using resin material with elastic deformation capability instead of rigid metal. The slit introduces controlled flexibility, allowing the member to deform elastically under lateral forces and then recover, maintaining both assembly efficiency and withstand load capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The resin cylindrical member with a slit functions as a flexible structure that can elastically deform in the radial direction. This flexibility allows the member to accommodate lateral forces that try to dislodge the input rod while maintaining secure locking, replacing rigid swaged structures with a flexible, resilient solution.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If the cylindrical member is rigid to ensure secure locking, then locking reliability is maintained, but assembly becomes difficult and time-consuming

Engineering Contradiction:
Improvelocking securityVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the rigidity parameter of the cylindrical member by introducing a slit that enables elastic deformation. This allows the member to be flexible during assembly for easy installation while maintaining sufficient rigidity when engaged to ensure secure locking of the input rod in the piston.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cylindrical member transitions from a static, rigid structure to a dynamic, elastic structure that can deform during assembly and operation. The slit enables the member to flexibly adapt during assembly while maintaining locking security, improving ease of operation without compromising reliability.

Inventive Principle:
Principle #15Dynamics

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 configuration improves productivity by reducing machining hours and costs, while ensuring secure locking and eliminating backlash, thus enhancing the operational efficiency and reliability of the input device.

Implementation Method 1

a slit formed over the length of the whole of the cylindrical member in the axial direction. The cylindrical member can be elastically deformed in a radial direction due to the slit

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

since the slit can cause resilience of the rod receiving part relative to the end part of the input rod, it is possible to eliminate backlash of the input rod in the axial direction

Methodology Applied
Scientific EffectResilience: Elasticity

Data Source

PatentEP3184385B1Input device
Publication Date: 2021.11.10 AUTOLIV NISSIN BRAKE SYST JAPAN CO LTD
  • EP3184385B1 patent drawingFigure 1
  • EP3184385B1 patent drawingFigure 2
  • EP3184385B1 patent drawingFigure 3

AI summary

An input device includes an input rod, a piston, and a cylindrical member. The cylindrical member includes a rod, a locking part, and a slit. The rod receiving part is provided on one end side in an axial direction and configured to receive the end part of the input rod. The locking part is formed on the other end side in the axial direction so as to lock an engaging part of the piston, thereby preventing the input rod from falling off the piston. The slit is formed over the length of the whole of the cylindrical member in the axial direction. The cylindrical member can be elastically deformed in a radial direction due to the slit.