Variable Support Arm Rotary Rake Drive Reliability
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Solution Overview
Problem
Current rotary swathers face challenges in providing reliable drives and ground adaptation due to insufficient displacement paths in drive cardan shafts, leading to issues with working width adjustments and negative impacts on ground tracking.
Innovation Solution
A rotary swather design with a variable-length support arm and a transfer case positioned 30% to 75% of the rotary rake's outer diameter from the central axis, allowing drive cardan shafts to extend at an angle, optimizing the change in length of drive shafts relative to height changes, and limiting the quotient of change in length to 8% or less for improved ground adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the support arm length is increased to provide sufficient displacement path for drive shafts in working position, then the drive reliability is improved, but the transport height becomes excessively high
Solution Approach 1:
The support arm length is made variable rather than fixed. The support arm can be extended to a first length during working position to provide sufficient displacement path for drive shafts, ensuring reliable drive operation. During transport position, the support arm is retracted to a second, shorter length to minimize transport height. This dynamic adjustment resolves the contradiction between drive reliability and transport height requirements.
2Reliability
If the support arm pivot axis tilt angle is increased to improve ground adaptation, then the ground tracking quality is improved, but the change in drive shaft length becomes excessive
Solution Approach 1:
The tilt angle of the support arm pivot axis is optimized within a specific range (5° to 15°) to achieve the best compromise between ground adaptation and drive shaft length stability. This parameter optimization ensures that the rotary rakes adequately follow ground contours while minimizing excessive changes in drive shaft length that would compromise drive reliability.
Solution Approach 2:
The variable support arm length works in conjunction with the pivot axis tilt angle to dynamically adjust the drive shaft operating conditions. When the support arm length is adjusted, it compensates for the effects of pivot axis tilt, maintaining drive shaft length within acceptable limits while preserving ground adaptation capability.
3Productivity
If the working width is increased to improve productivity, then the harvesting efficiency is improved, but the displacement path requirements for drive shafts become insufficient
Solution Approach 1:
The variable support arm length provides the necessary displacement path for drive shafts even when working width is increased. By extending the support arm to a first length during working operations, sufficient displacement path is ensured for the drive shafts to accommodate the larger working width, thereby maintaining both productivity and drive reliability.
Data Source
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AI summary
Rotary rake with a machine frame (2) extending in the direction of travel and work (F) and with at least one rotary rake (3) arranged on each side of the machine frame and driven around a vertical axis, which can be moved from a working position parallel to the ground to an at least approximately vertical transport position and back via a support arm (9) oriented at least approximately transversely to the machine frame (2) and whose length can be varied, wherein each support arm (9) is pivotably mounted on the machine frame (2) about a support arm pivot axis (11) inclined at an acute angle to a horizontal plane, and wherein a drive device is provided for driving the rotary rakes (3), which is formed from a distribution gearbox (12) and a drive shaft (13) extending from the distribution gearbox (12) to each of the rotary rakes (3), wherein the distribution gearbox (12) is arranged in a region relative to the rotary rakes (3),which is positioned upstream or downstream of the gyratory rake (3) by a distance of 30% to 75% of the outer diameter of the gyratory rake (3). (Fig. 2)