E-latch Magnetic Snap Assembly Reduces Attachment Time
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Solution Overview
Problem
Existing systems for detecting the operative condition of a vehicle door latch are slow and costly to assemble due to methods involving glue, resin, or over-molding, which require extended drying times or additional magnetization steps.
Innovation Solution
A system comprising a magnetic field generating element snap-fitted into a housing with elastically deformable retaining elements, allowing for quick and secure assembly, where a permanent magnet is coupled with a Hall effect sensor to detect the latch's operative condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the magnet is fixed by using glue or resin to the plastic part of the rotatable element, then the magnet is securely attached, but the assembly time is significantly increased due to drying time requirements
Solution Approach 1:
The patent replaces chemical bonding (glue/resin) with a mechanical snap-fit system. The magnet is attached to the rotatable element through a snap-fit connection that uses elastic deformation of retaining elements to secure the magnet mechanically, eliminating the need for drying time associated with adhesive bonding while maintaining secure attachment.
Solution Approach 2:
The patent divides the attachment system into separate components: the magnet, the rotatable element with cavity, and elastic retaining elements. This segmentation allows the magnet to be quickly inserted and mechanically secured without requiring chemical bonding, thus reducing assembly time while ensuring secure attachment through the elastic retention mechanism.
2Strength
If the magnet is over-molded inside the plastic rotatable element, then the magnet is securely integrated, but additional magnetization steps are required which increase assembly time
Solution Approach 1:
The patent replaces the over-molding process with a mechanical snap-fit system. Instead of integrating the magnet through plastic molding (which requires subsequent magnetization), the magnet is mechanically attached using elastic retaining elements that snap into place, eliminating the need for additional magnetization steps and reducing assembly time.
Solution Approach 2:
The magnet is pre-attached to the rotatable element through the snap-fit mechanism before final assembly into the latch system. This preliminary attachment using mechanical retention eliminates the need for post-assembly magnetization steps, as the magnet is already securely in position and magnetized when inserted into the housing.
3Loss of time
If a snap-fit system is used to attach the magnet to the housing, then assembly time is reduced, but the attachment strength may be compromised
Solution Approach 1:
The patent uses elastic retaining elements that can dynamically deform during insertion and then return to their original shape to secure the magnet. This dynamic elastic deformation allows for quick insertion while maintaining strong attachment, as the elastic material can flex during assembly and then provide continuous retention force to secure the magnet firmly in place.
Solution Approach 2:
The patent employs composite construction with the housing containing both rigid structural elements and elastic retaining elements. This combination of rigid and elastic materials allows the snap-fit system to achieve both quick assembly (through the rigid housing structure) and strong attachment (through the elastic retaining elements that deform and lock the magnet in place).
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 solution significantly reduces assembly time by enabling the magnet to be easily and securely inserted into the housing, allowing for rapid detection of the latch's operative condition without the need for lengthy drying processes or additional magnetization steps.
Implementation Method 1
a magnetic field generating element adapted to generate a magnetic field which is associated to the operative condition of the latch
Implementation Method 2
a Hall effect sensor mounted on the printed circuit board. Very briefly, the sensor outputs an electrical signal which varies with the magnetic field detected by the same sensor
Implementation Method 3
The housing comprises at least one retaining element which extends into cavity, is elastically deformable when the generating element is inserted inside the cavity and elastically returns to snap-lock the generating element inside the cavity
Data Source
AI summary
A system for detecting the operative condition of a latch for a door of a motor-vehicle, comprises a magnetic field generating element adapted to generate a magnetic field which is associated to the operative condition of latch; a support which defines a housing for magnetic field generating element; and a sensor magnetically coupled with magnetic field generating element and adapted to sense the magnetic field. The generating element is snap-fitted to the housing.