Outward Lock Spring Arms for Vehicle Seat Recliner
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Solution Overview
Problem
Existing reclining devices for vehicle seats face issues with friction and wear due to spring arms extending inwardly, leading to malfunction and increased manufacturing costs due to strict tolerances required for correct operation.
Innovation Solution
A reclining device with a lock spring design where spring arms extend outwardly from the lock spring body, providing a larger contact area and allowing greater tolerances, reducing friction and dependency on exact geometry and stiffness, and featuring a wedge engaging element for direct interaction with wedge elements to prevent self-rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring arms extend inwardly from the lock spring body, then the lock spring can engage the wedge elements, but friction and wear increase leading to malfunction
Solution Approach 1:
The spring arms are inverted from the conventional inward extension to outward extension from the lock spring body. This inversion eliminates the friction and wear problems caused by inward extension while maintaining the engagement function with wedge elements through the outwardly extending arms that can still interact with the wedge elements when needed
2Ease of manufacture
If spring arms extend inwardly from the lock spring body, then the lock spring structure is compact, but strict tolerances are required increasing manufacturing costs
Solution Approach 1:
By inverting the spring arm extension direction to outward, the design reduces dependency on precise geometric tolerances and stiffness requirements. The outward extension provides a larger contact area and more favorable stress distribution, allowing for greater manufacturing tolerances and reducing production costs
3Object-generated harmful factors
If spring arms extend outwardly from the lock spring body, then friction and wear are reduced, but the contact area with wedge elements decreases
Solution Approach 1:
The outward extension of spring arms actually provides a larger contact area with the wedge elements compared to inward extension. The outwardly extending arms have more space to engage and can distribute the contact force over a larger surface area, reducing pressure and friction while maintaining effective engagement
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 enhances reliability by reducing friction and wear, simplifying kinematic transmission, and lowering manufacturing costs by allowing less stringent tolerances in lock spring production.
Implementation Method 1
a wedge spring, which has an omega-shape comprising a circular portion ending with two, parallel arms... The wedge spring biases the wedge elements apart from each other
Implementation Method 2
said locking teeth are configured to be received in a space between two consecutive teeth of a ring gear provided on said external gear
Implementation Method 3
The body of the lock spring is further provided with one or more spring arms that can engage a raised rim provided on the external gear and bias the locking teeth towards the teeth of the above-mentioned ring gear
Data Source
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AI summary
The invention relates to a reclining device (1) for a vehicle seat of the kind comprising a first plate (3) carrying an internal gear (5), and a second plate (9) carrying an external gear (11) cooperating with the internal gear. The reclining device includes a first and second wedge elements (17a, 17b) for preventing undesired rotation of the external and internal gears relative to each other. The reclining device (1) further includes a lock spring (21) comprising one or more locking teeth (41), intended to engage a ring gear (45) which is integral with one of said first and second plates for inhibiting relative rotation of said plates, and one or more spring arms (43), which elastically urge said locking teeth (41) towards said ring gear (45). According to the invention, said spring arms (43) outwardly extend from the outer perimeter of the body (31) of said lock spring, wherein each of said spring armes (43) comprises a first outwardly projecting portion (43a) and a second portion (43b) running along the outer periphery of said body (31) of said lock spring (21), said second portions (43b) of said spring arms (43) each spanning over an angle of more than 45° along the outer periphery of said body of said lock spring.