Vehicle Door Latch Power Unit Noise Reduction
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Solution Overview
Problem
Conventional vehicle door latch apparatuses with powered cinching mechanisms generate significant operation noise due to the separate placement of the power source, which limits design flexibility and increases noise levels despite the use of sound-proofing materials.
Innovation Solution
A vehicle door latch apparatus with a power unit integrated into the door, featuring a motor, cable drum, deceleration mechanism, and closed-type housing that includes a worm gear and helical gear, reduces operational noise by housing the motor and minimizing vibration through sound-proofing and vibration-damping measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power source of the powered cinching mechanism is arranged separately near the center of the vehicle door, then design flexibility is improved, but operation noise increases significantly
Solution Approach 1:
The patent merges the power source with the latch unit into a single integrated assembly, allowing both components to be positioned together at the rear end portion of the vehicle door. This integration enables the powered cinching mechanism to maintain high design flexibility while reducing operation noise, as the compact unified structure allows for effective sound-proofing and sound-absorbing material placement around the entire assembly.
2Object-generated harmful factors
If sound-proofing and sound-absorbing material is used to reduce noise from the separately arranged power source, then operation noise is reduced, but manufacturing cost increases
Solution Approach 1:
By integrating the power source with the latch unit, the patent creates a compact assembly that requires less sound-proofing material to achieve satisfactory noise levels. The unified structure allows noise control materials to be more efficiently placed around the entire assembly, reducing the total quantity of material needed and thereby lowering manufacturing costs while still achieving effective noise reduction.
3Ease of manufacture
If the power source is integrated with the latch unit, then manufacturing cost is reduced, but design flexibility is restricted due to narrow space constraints
Solution Approach 1:
The patent applies the nesting principle by integrating the power source within or alongside the latch unit structure, creating a compact nested arrangement. This allows both components to share the limited space at the rear end portion of the vehicle door effectively, achieving cost-efficient integration while maintaining sufficient design flexibility through optimized spatial arrangement.
4Adaptability or versatility
If the power source is arranged separately, then design flexibility is improved, but the quantity of sound-proofing material required increases
Solution Approach 1:
The integration of the power source with the latch unit creates a compact unified assembly that reduces the volume requiring sound-proofing coverage. By consolidating both components into one location, the patent minimizes the total surface area that needs sound-proofing and sound-absorbing material, thereby reducing the quantity of material required while maintaining design flexibility.
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 effectively reduces operation noise to a satisfactory level while saving costs by integrating the power unit into the vehicle door, enhancing sound quality and reducing noise levels to 42.2-46.5 dB.
Implementation Method 1
The deceleration mechanism includes a worm gear and a helical gear.
Implementation Method 2
The deceleration mechanism includes a worm gear and a helical gear.
Implementation Method 3
a cable drum onto which one end of the cable is wound and that takes up and feeds the cable
Implementation Method 4
a first cinching lever that is rotated to displace the latch from the half-latched position to the full-latched position
Implementation Method 5
a ratchet that prevents the latch from rotating in an unlatching direction when the ratchet engages the half-latching step and the full-latching step
Data Source
AI summary
A power unit for a powered cinching mechanism with a favorable level of operational noise is provided. A door latch apparatus includes latch unit and power unit. Latch unit has latch that engages striker, ratchet that engages latch and first cinching lever that displaces latch from a half-latched position to a full-latched position. Latch unit is attached to an end portion of a vehicle door. Power unit includes motor, cable drum, deceleration mechanism and closed-type housing that houses them. Operational noise at 300 mm right above the housing of power unit is 42.2 to 40.9 dB at a supply voltage to the motor of 9V, 47.5 to 43.9 dB at a supply voltage of 12V, and 49.7 to 46.5 dB at a supply voltage of 16 V. Deceleration mechanism includes a worm gear and a helical gear.