Vehicle Seat Sensor Layout for Harness Space and Occupant Detection
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Solution Overview
Problem
In vehicle seats, particularly rear seats, there is insufficient space on the back side of the seat cushion and seat back to accommodate wire harnesses due to the support by vehicle body panels, and existing seat sensors face challenges in accurately distinguishing between a seated occupant and an object, especially when the seating posture varies.
Innovation Solution
A vehicle seat design with a recess on the back side of the pad to accommodate wire harnesses and a combination of pressure sensors and capacitance sensors to determine if an occupant is seated, with the capacitance sensor positioned on the seat back to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pad is supported by the vehicle body panel, then the seat structure is stable and strong, but there is insufficient space on the back side of the pad to accommodate wire harnesses
Solution Approach 1:
The patent introduces a recess on the back surface of the pad that extends in the depth direction (third dimension) to create wire harness accommodation space. This recess is formed at a position away from the vehicle body panel, utilizing the Z-axis dimension rather than compromising the panel support structure. The wire harness passage connects this recess to the front surface, allowing harness routing without interfering with the panel-pad support relationship.
2Measurement precision
If a pressure sensor is used to detect seat occupancy, then the sensor can detect pressure applied to the seating surface, but it cannot accurately distinguish between a seated occupant and an object
Solution Approach 1:
The patent combines a pressure sensor and a capacitance sensor into a single integrated seat sensor unit. The pressure sensor detects pressure applied to the seating surface, while the capacitance sensor detects changes in capacitance caused by the presence of an occupant. By merging these two sensing mechanisms and analyzing their combined output, the system can distinguish between occupants and objects with higher accuracy than either sensor alone.
Solution Approach 2:
The patent utilizes different physical parameters for detection: pressure (from the pressure sensor) and capacitance (from the capacitance sensor). By monitoring changes in both parameters simultaneously and comparing their patterns, the system can differentiate between the electrical properties of human bodies and inanimate objects, thereby improving detection accuracy without significantly increasing system complexity.
3Measurement precision
If the capacitance sensor is positioned on the seat back, then detection accuracy for varying seating postures is improved, but the device complexity increases
Solution Approach 1:
The capacitance sensor positioned on the seat back serves multiple functions: it detects occupancy presence, determines seating posture (seated vs. reclined), and works in conjunction with the pressure sensor to distinguish occupants from objects. This multi-functional capability is achieved through strategic placement rather than adding separate dedicated sensors for each function, thereby limiting the increase in device complexity.
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 allows for efficient placement of wire harnesses without interference and accurately differentiates between an occupant and an object, ensuring reliable detection across varying seating postures.
Implementation Method 1
The pressure sensor is a sensor that detects the pressure applied to the seating surface of the seat cushion
Implementation Method 2
a capacitance sensor (240) positioned on the seat back (205)
Data Source
AI summary
A wire harness connected to a sensor is positioned on a back surface of a pad of a vehicle seat supported by a panel. The vehicle seat (1) includes a panel (4); a pad (11, 51) supported by the panel; a skin material (12, 52) covering a front surface of the pad; and a sensor (32) provided between the front surface of the pad and the skin material for acquiring information on a seat occupant, wherein the pad is provided with a through hole (35, 58) passed from the front surface of the pad to a back surface of the pad, and a recess (45, 61) formed in the back surface of the pad and connected to the through hole, the wire harness connected to the sensor extending in the through hole and the recess.