Sensor Unit Spring Retention Structure for Easier Assembly
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Solution Overview
Problem
The existing sensor unit design is prone to coil spring loss during assembly due to the coil spring not being held by the housing components, leading to complex assembly processes.
Innovation Solution
A sensor unit design where the lower housing supports one end of the coil spring, and the upper housing has a positioning protrusion with a receiving recess and guide surfaces to securely hold the coil spring, allowing it to be assembled without loss and improving assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the coil spring is not held by the lower housing or upper housing before assembly, then the assembly structure is simpler, but the coil spring may be lost during assembly
Solution Approach 1:
The lower housing is designed with a support portion that can preliminarily hold the coil spring before the final assembly with the upper housing. This preliminary holding action prevents the coil spring from being lost during the assembly process while maintaining a relatively simple overall structure.
2Reliability
If the coil spring is held by the lower housing or upper housing, then the coil spring is securely retained, but the assembly operation becomes more complicated
Solution Approach 1:
The holding function is segmented between two components: the lower housing provides preliminary holding through its support portion, and the upper housing provides final securing through the positioning protrusion. This segmentation allows each component to have a simple, focused structure while achieving reliable coil spring retention throughout the assembly process.
3Device complexity
If the positioning protrusion directly inserts into the coil spring without engagement projection, then the structure is simpler, but the positioning protrusion cannot be securely locked
Solution Approach 1:
The engagement projection on the coil spring serves a dual function: it guides the positioning protrusion during insertion and then locks itself into the receiving recess through elastic deformation. The coil spring's own elastic properties enable the self-locking mechanism without requiring additional complex components.
4Reliability
If the engagement projection is rigid, then the locking is more secure, but the positioning protrusion cannot be inserted into the coil spring
Solution Approach 1:
The engagement projection is designed with elastic properties that allow it to dynamically change its shape. During insertion, it deforms elastically to accommodate the positioning protrusion, and after insertion, it elastically recovers to lock securely in the receiving recess. This dynamic behavior enables both easy insertion and secure locking.
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 design reduces the likelihood of coil spring loss and simplifies the assembly process by securely holding the coil spring, enhancing the overall workability of the sensor unit.
Implementation Method 1
the lower housing is biased toward the detection target in response to elastic recovery of the coil spring
Implementation Method 2
due to deflection and deformation of the engagement projection, the positioning protrusion is allowed to be inserted into the coil spring, and due to elastic recovery of the engagement projection, the engagement projection is received and locked
Data Source
AI summary
A sensor unit includes: a conductive path structure; a sensor element; a lower housing including a sensor element accommodation part; a coil spring; and an upper housing. The lower housing includes a support portion, and the upper housing includes a positioning protrusion that protrudes in the shape of a tapered tube toward the lower housing, and is inserted into another end of the coil spring in the axial direction. The lower housing is displaceable toward the positioning protrusion, the coil spring includes an engagement projection that projects to the inner circumferential side thereof so as to be deflectable and deformable. The positioning protrusion has a receiving recess, and the engagement projection is received and locked in the receiving recess, so that the coil spring is held by the upper housing.