Refrigerator Door Knock Sensor Mounting to Reduce Cold Air Impact
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Solution Overview
Problem
Existing refrigerators face challenges in accurately sensing knock signals due to the influence of cold air and humidity on the knock sensing device, which deteriorates its sensing accuracy and makes it difficult to access and replace the sensor module.
Innovation Solution
The refrigerator design includes a sensor module installed on the door frame, spaced apart from the front panel, with a mounting portion that accommodates a sensor PCB and element, allowing for improved vibration transmission and reduced exposure to cold air, enhancing sensing accuracy and serviceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the knock sensing device is in contact with the rear surface of the front panel to sense sound waves, then the sensing capability is improved, but the sensing accuracy deteriorates due to exposure to cold air and humidity
Solution Approach 1:
The door structure is segmented into multiple components: the front panel, the door frame, and the knock sensing device are separated. The sensing device is mounted on the door frame rather than directly on the front panel, creating spatial separation that isolates the sensor from harmful environmental factors while maintaining sensing capability through structural vibration transmission.
Solution Approach 2:
The door frame acts as an intermediary element between the front panel and the knock sensing device. It transmits vibrations from the front panel to the sensing device while simultaneously protecting the sensor from direct exposure to cold air and humidity, thus mediating between sensing requirements and environmental protection.
2Measurement precision
If the sensor module is installed on the door frame spaced apart from the front panel, then the sensing accuracy is improved by reducing exposure to cold air, but the vibration transmission may be weakened
Solution Approach 1:
The knock sensing device includes a knock transmission enhancing element with a curved surface that contacts the front panel. This curved contact surface increases the contact area and improves vibration transmission efficiency from the front panel to the sensing device, compensating for the spatial separation between the sensor and panel.
Solution Approach 2:
The knock transmission enhancing element is made of a material with high vibration transmission characteristics, forming a composite structure that efficiently transmits mechanical vibrations from the front panel through the element to the sensing device, maintaining force transmission despite increased distance.
3Reliability
If the sensor module is spaced apart from the front panel, then the reliability is improved by minimizing cold air impact, but the ease of repair deteriorates due to reduced accessibility
Solution Approach 1:
The sensor module is segmented as a separate, independently replaceable component mounted on the door frame. This segmentation allows the sensing device to be accessed, removed, and replaced without disassembling the entire door structure, maintaining ease of repair despite being spaced from the front panel.
Solution Approach 2:
The door frame serves multiple functions: it provides structural support for the door, acts as a mounting platform for the knock sensing device, and facilitates sensor replacement. This multi-functionality enables the sensing device to be positioned optimally for reliability while maintaining accessibility for maintenance.
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 configuration enables accurate sensing of knock signals while minimizing the impact of cold air and humidity, improving the reliability and ease of maintenance of the knock sensing system.
Implementation Method 1
a knock sensing device disposed on a rear surface of the panel assembly to sense user's knock manipulation of the panel assembly
Implementation Method 2
The knock sensing device includes a microphone module that is in contact with the rear surface of the front panel to receive a sound wave generated by vibration during a knock transmitted through the front panel
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A refrigerator includes a cabinet having a storage space and a door to open and close the storage space. The door includes a panel assembly including a front panel, a door frame connected to the panel assembly, a door liner connected to the panel assembly and the door frame and to define an insulating space, in which an insulator is disposed, together with the panel assembly and the door frame, and a sensor module installed on the door frame to sense a knock input applied to the front panel. The door frame includes a front wall that is in contact with the front panel and a rear wall spaced apart from the front wall and configured to define an accommodation space, in which the sensor module is accommodated, together with the front wall.