Torque Rod Bolt Fixing for Liquid-Tightness

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Solution Overview

Problem

Existing torque rods face challenges in firmly fixing the support shaft of the actuator within the third accommodation portion and ensuring liquid-tightness inside this compartment.

Innovation Solution

The torque rod design incorporates a bolt system where the bolt is screwed into the support shaft, with the bolt's head pressing against an annular flat surface, and the support shaft's end surface pressing against a thicker partition wall, creating a secure and sealed environment by using a communication hole and counterbore configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support shaft is simply installed in the third accommodation portion without additional fixing structures, then the device complexity is reduced, but the support shaft cannot be firmly fixed and liquid-tightness cannot be ensured

Engineering Contradiction:
Improvefixing reliability and liquid-tightnessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bolt is nested within the communication hole and counterbore structure of the partition wall. The head of the bolt fits into the counterbore which is recessed into the partition wall, creating a nested configuration that securely fixes the support shaft while maintaining a compact design without adding external complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The communication hole and counterbore act as intermediary structures that mediate between the bolt and the partition wall. These intermediary features enable the bolt to firmly secure the support shaft and ensure liquid-tightness without requiring direct modification of the main partition wall structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a complex fixing structure is used to firmly secure the support shaft and ensure liquid-tightness, then the fixing reliability is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvefixing reliability and liquid-tightnessVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The partition wall is segmented by creating a communication hole and a counterbore feature. This segmentation allows the bolt to be installed and secured in a distributed manner, with the counterbore providing a localized recess that simplifies the fixing process and reduces manufacturing complexity compared to a monolithic complex structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The counterbore structure serves multiple functions simultaneously: it provides a recess for the bolt head, ensures liquid-tightness through its geometric configuration, and simplifies assembly by guiding the bolt into position. This self-service design reduces the need for additional complex fixing mechanisms

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3369962B1Torque rod
Publication Date: 2020.04.08 BRIDGESTONE CORP
  • EP3369962B1 patent drawingFigure 1
  • EP3369962B1 patent drawingFigure 2

AI summary

There is provided a torque rod (1) in which any one of a partition wall (27) between an interior of a first accommodation portion (15) for accommodating a first elastic bush (11) and an interior of a third accommodation portion (17) for accommodating an actuator (14) and a partition wall (28) between an interior of a second accommodation portion (16) for accommodating a second elastic bush (12) and the interior of the third accommodation portion (17) has a communication hole (29) for allowing the interiors of both the accommodation portions to communicate with each other, and a whole area of the other partition wall is closed. In the communication hole (29), a counterbore (29a) is formed in an end portion on a side opposite to the third accommodation portion (17). The torque rod includes a bolt (30) that is inserted into the communication hole (29), and that has a head portion (30a) accommodated in the counterbore (29a). The bolt (30) is screwed into a support shaft (24) or the communication hole (29) so that the head portion (30a) is pressed against an annular flat surface (29c) which faces a side opposite to the third accommodation portion (17) on an inner surface of the counterbore (29a), and the support shaft (24) is pressed against the partition wall (28).