Automotive Sunshade Torsion Spring and Rack Drive Mechanism
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Solution Overview
Problem
Existing motorized sunshade apparatuses for automobiles installed on rear shelves face issues with low structural strength, generating shocks, vibrations, and noise due to complex and unreliable stopping mechanisms and elongated tension springs that increase weight and operational noise.
Innovation Solution
A sunshade apparatus with a sunshade screen wound around a casing biased by an elastic member, featuring arm units with torsion springs and a drive unit using small-diameter gears and racks to minimize noise and vibration, and a stopping mechanism with a bent protrusion and engaging groove for precise control, reducing operational noise and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tension spring is used to bias upper arm members and promote rotating motion, then the arm members can be easily stretched, but the tension spring becomes elongated and exceeds the length of the shade bar, making assembly difficult and increasing weight
Solution Approach 1:
The tension spring is divided into multiple segments or coils along its length, with each segment providing elastic biasing force. This segmentation allows the spring to achieve the required elongation and biasing function while maintaining a compact overall length that fits within the shade bar structure, thereby resolving the assembly difficulty without compromising the ease of stretching arm members
Solution Approach 2:
The tension spring is designed to be nested within or alongside other structural components of the shade bar assembly. By nesting the spring within the existing structure, the spring's elongated form is accommodated without increasing the external dimensions or complicating the assembly process, thus maintaining ease of operation while reducing device complexity
2Ease of operation
If a tension spring is used to bias upper arm members, then the arm members can be easily stretched, but the tension spring generates metal scratching noise and vibration during extension and contraction
Solution Approach 1:
A damping material or coating is introduced as an intermediary between the tension spring and the surrounding structure. This intermediary layer absorbs the metal scratching noise and vibration generated during spring extension and contraction, while allowing the spring to maintain its elastic biasing function for easy stretching of arm members
Solution Approach 2:
The tension spring is covered with a flexible damping shell or thin film that reduces metal scratching noise and vibration. This flexible covering allows the spring to move and stretch freely while suppressing harmful noise and vibration, thus maintaining ease of operation without generating disturbing sounds
3Ease of operation
If a tension spring is used to bias upper arm members, then the arm members can be easily stretched, but the tension spring increases the weight of the shade bar, requiring increased power from the drive unit
Solution Approach 1:
The tension spring is redesigned with modified parameters such as reduced wire diameter, optimized coil density, or alternative material selection. These parameter changes reduce the spring's weight while maintaining sufficient elastic biasing force to enable easy stretching of arm members, thereby reducing the overall weight of the moving object without compromising ease of operation
Solution Approach 2:
The tension spring is replaced with a lighter alternative component or design that provides similar biasing functionality with reduced weight. This substitution reduces the weight of the moving object and the power requirements of the drive unit, while still achieving the ease of stretching arm members through alternative mechanical means
4Reliability
If a stopping means with pin protrusion and engaging groove is provided to prevent excessive rotation, then the arm members can be controlled, but the production process becomes complicated and the stopping means may be deformed and abraded after repeated use
Solution Approach 1:
The stopping means is designed as a self-aligning or self-adjusting mechanism that automatically positions itself to prevent excessive rotation of arm members. This self-service design eliminates the need for complex pin protrusion and engaging groove assembly processes, while providing reliable rotational control through the inherent geometry of the components
Solution Approach 2:
Instead of using a pin protrusion that fits into a groove, the design inverts the approach by using a groove that receives a protrusion, or by using a cam-based stopping mechanism. This inversion simplifies the production process by reducing the number of precise fitting operations required, while maintaining reliable control over arm member rotation
5Reliability
If a stopping means with pin protrusion and engaging groove is provided to prevent excessive rotation, then the arm members can be controlled, but the pin protrusion and engaging groove may be deformed and abraded after repeated use, generating operational noise
Solution Approach 1:
The stopping means is constructed using composite materials that combine the hardness needed for durability with the toughness required to resist deformation and abrasion. This composite construction extends the service life of the stopping mechanism by preventing wear and deformation, thereby maintaining reliable rotational control and eliminating operational noise over extended periods
Solution Approach 2:
The stopping means is designed with built-in cushioning or shock-absorbing features that reduce impact forces during operation. This beforehand cushioning prevents deformation and abrasion of the pin protrusion and engaging groove by minimizing mechanical stress, thereby extending the duration of action and preventing operational noise generation
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 reliable, durable, and lightweight sunshade apparatus with reduced noise and vibration, suitable for low structural strength rear shelves, ensuring smooth operation and improved assembly efficiency.
Implementation Method 1
a sunshade screen wound around a winding roll, the winding roll being installed inside a casing and being biased by an elastic member
Implementation Method 2
torsion springs are fitted over respective pivots, which joint the upper arm members of the first and second arm units to the shade bar
Data Source
AI summary
The present invention relates to a sunshade apparatus for automobiles. In the apparatus, first and second linking rods, which function to stretch or close first and second arm units jointed to a shade bar, are actuated by first and second racks, which are engaged with motor-operated first and second drive pinions and are rectilinearly moved in opposite directions. Further, torsion springs are fitted over respective pivots, which joint the upper arm members of the first and second arm units to the shade bar, such that the torsion springs can promote the stretching of respective upper arm members. The torsion springs can be easily assembled in the apparatus, do not generate vibration or noises, and are light, thus reducing the power required to move the shade bar upwards or downwards. Therefore, the present invention realizes the smallness of the drive unit and the lightness of the sunshade apparatus.