Sliding Door Drive With Pivotable Support Arm
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Solution Overview
Problem
Existing sliding door drives for public transport vehicles experience issues with bending and shearing forces, leading to component tilting, increased edge pressure, and one-sided loading of the spindle nut, making reverse operation by hand difficult and prone to jamming, especially due to transverse forces and bending moments not being adequately managed.
Innovation Solution
A sliding door drive design featuring a drivable spindle with a spindle nut enclosed by an inner ring element and an outer fork element, allowing pivotal and linear movements to absorb and redirect forces, keeping the spindle nut free from disruptive loads, and enabling compact, space-saving, and cost-effective installation without requiring changes to the sliding door leaf.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a connecting rod with swivel joints is used to connect the drive spindle to the carriage, then the sliding door can be displaced and rotated, but the connecting rod experiences bending and shearing forces that require the swivel joints to be designed with high resistance
Solution Approach 1:
The support arm is divided into two separate pivotable connections: a first pivotable connection to the carriage and a second pivotable connection to the drive spindle. This segmentation allows each connection to handle specific movement components independently, preventing the accumulation of bending and shearing forces that would otherwise require overly robust swivel joints.
Solution Approach 2:
The support arm acts as an intermediary element between the carriage and the drive spindle. It mediates the force transmission by providing pivotable connections that accommodate relative movements and misalignments, thereby protecting the swivel joints from excessive bending and shearing forces while maintaining the mechanical linkage.
2Ease of operation
If the carriage and spindle nut are positioned at a relatively large distance from each other, then the sliding door can be operated, but both components are subject to tilting on their seats during operation, leading to increased edge pressure and one-sided loading
Solution Approach 1:
The support arm is designed with pivotable connections that allow dynamic adjustment of the mechanical linkage during operation. This enables the system to adapt to component tilting and positional variations, distributing loads more evenly and preventing excessive edge pressure and one-sided loading on the spindle nut while maintaining operational capability.
3Ease of operation
If the spindle nut is driven by hand during reverse operation, then the sliding door can be moved in reverse, but parallel displacement of the carriage and spindle nut is almost impossible due to component canting and wear
Solution Approach 1:
The pivotable connections of the support arm provide dynamic compensation for component canting and wear during reverse operation. When the spindle nut is driven by hand, the pivotable joints allow the support arm to self-adjust and accommodate misalignments, maintaining reliable parallel displacement capability despite tolerances and wear that would otherwise prevent accurate reverse movement.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a sliding door drive (20). The sliding door drive (20) has: a drivable spindle (24) having a Z longitudinal axis, a spindle nut (20) which is movable on the spindle (24) along the Z longitudinal axis, an inner ring element (30) which surrounds the spindle nut (22) and is connected to the spindle nut (22) via two mutually diametrically opposite first shaft butts (28), which form a Y axis, in such a manner that the inner ring element (30) is pivotable about the Y axis and is displaceable along the Y axis, and an outer fork element (34) which is connected to the inner ring element (30) via two mutually diametrically opposite second shaft butts (32), which form a X axis, in such a manner that the outer fork element (34) is pivotable about the X axis and is displaceable along the X axis, wherein the outer fork element (34) has a support arm (26) for connection to the sliding door.