Captive Spacer Formed by Overmolding Accelerometer Mounting Base

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Solution Overview

Problem

The existing methods for mounting accelerometer sensors face challenges in securely holding a centering spacer in the central bore of the mounting base, leading to quality control issues and increased costs due to the risk of spacer loss or incorrect positioning during storage, transport, and assembly.

Innovation Solution

A method where the spacer is formed integrally within the central bore of the mounting base during the overmolding of plastic material, ensuring it is captive and securely attached to the encapsulation, eliminating the need for additional assembly steps and reducing the risk of spacer loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a separate centering spacer is inserted into the central bore during assembly, then the fastening element can be centered in the central bore, but the spacer may be lost or incorrectly positioned during storage, packaging, transport, and manipulation

Engineering Contradiction:

Improvecentering spacer positioningVSAvoidspacer retention

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention merges the centering spacer and the encapsulation into a single integrated component. The spacer is formed as an integral part of the encapsulation material that overmolds the mounting base, eliminating the need for a separate spacer component. This integration ensures the spacer cannot be lost or incorrectly positioned, as it is permanently formed within the encapsulation structure during the overmolding process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The centering spacer is formed in advance during the encapsulation overmolding process, before the sensor undergoes storage, packaging, transport, and assembly operations. By creating the spacer as part of the encapsulation material that flows into and solidifies within the central bore, the spacer is pre-positioned and secured, eliminating subsequent risks of loss or mispositioning.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If a separate centering spacer is used, then the M6 screw can be centered in the central bore, but additional quality control checks and visual identification methods are required

Engineering Contradiction:

Improvefastening element centeringVSAvoidquality control procedures

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention combines the centering function with the encapsulation structure itself. The encapsulation material flows through the central bore during overmolding, forming an integrated spacer that centers the fastening element. This eliminates the need for separate quality control checks, visual identification markers, or additional assembly steps, as the centering function is inherently built into the encapsulation process.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the spacer is formed integrally with the encapsulation during overmolding, then the spacer is permanently held in position and cannot be lost, but the plastic material must flow through the barrel during overmolding

Engineering Contradiction:

Improvespacer retentionVSAvoidovermolding process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention segments the overmolding process by creating a dedicated flow path through the barrel that allows encapsulation material to specifically reach and form the spacer in the central bore. This segmentation enables the spacer formation to be integrated into the existing overmolding process without requiring separate manufacturing steps, maintaining ease of manufacture while achieving integral spacer formation.

Inventive Principle:

Principle #1Segmentation

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 provides a robust and reliable attachment of the spacer, preventing its loss and ensuring correct positioning, thereby enhancing the sensor's structural integrity and simplifying the assembly process while reducing costs associated with quality control measures.

Implementation Method 1

when the plastic material is overmolded around the mounting base to form the encapsulation, part of the plastic material passes through the barrel to form the spacer while fixing it to the encapsulation

Methodology Applied

Scientific EffectOvermolding:

Data Source

PatentUS10132822B2Method for forming a captive spacer housed in a mounting base of an accelerometer sensor and sensor equipped with such a mounting base

Publication Date: 2018.11.20 VITESCO TECHNOLOGIES GMBH

AI summary

Disclosed is a method for forming a spacer extending at least partially within the length of a central bore passing from one side to the other of a barrel of a mounting base of an accelerometer sensor, the central bore being designed to receive a fastening element for fixing the mounting base onto a support element, the fastening element being centered by the spacer in the central bore, the mounting base being at least partially surrounded by an encapsulation of overmolded plastic material. When the plastic material is overmolded around the mounting base to form the encapsulation, a part of the plastic material passes through the barrel to form the spacer while fixing it to the encapsulation. Also described is a mounting base with at least one channel for the passage of the plastic material, and to an accelerometer sensor equipped with such a mounting base.