Transfer Output Shaft Centering to Reduce Spline Backlash Vibration
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Solution Overview
Problem
In four-wheel-drive vehicles, the transfer device experiences vibration and loosening of bolt members due to backlash in the spline-engagement between the propeller shaft and the output shaft, leading to instability and assemblability issues.
Innovation Solution
The transfer device incorporates a hollow end part on the auxiliary-drive-wheel output shaft with a centering part and a flange part, along with a spacer and bolt member configuration, to center the joint part and prevent loosening by creating a gap that resists rotational forces, while an intermediate shaft part further reduces vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-press fitted spline-engagement is used between the joint part and the auxiliary-drive-wheel output shaft, then assemblability is improved and the bolt member is retained, but vibration occurs due to backlash
Solution Approach 1:
A centering part is introduced as an intermediary component between the joint part and the auxiliary-drive-wheel output shaft. This centering part includes a centering portion that fits into a centering hole in the auxiliary-drive-wheel output shaft, providing precise alignment and reducing backlash-induced vibration while maintaining the non-press fitted spline-engagement for ease of assembly
Solution Approach 2:
The connection structure is segmented into distinct functional components: the spline-engagement portion for power transmission, the centering part for alignment, and the bolt member for retention. This segmentation allows each component to optimize its specific function - the spline teeth engage for torque transmission while the centering part eliminates radial play, resolving the vibration issue without compromising assemblability
2Reliability
If a bolt member is used to retain the propeller shaft, then the joint part is secured to the output shaft, but the bolt member may loosen due to relative rotation from backlash
Solution Approach 1:
The centering part serves as a mediator that eliminates relative rotation between the joint part and the auxiliary-drive-wheel output shaft by providing precise radial alignment through the centering portion and centering hole interface. This prevents the bolt member from loosening due to rotational movement while maintaining secure retention
Solution Approach 2:
The centering part is designed to establish precise alignment and eliminate backlash before the bolt member is fully tightened. This preliminary centering action ensures that when the bolt member is secured, there is no relative rotation or movement that could cause loosening during operation
Data Source
AI summary
A transfer device of a vehicle is provided, in which an auxiliary-drive-wheel output shaft extending in parallel with a main-drive-wheel output shaft is connected to a propeller shaft having a universal joint. An end part of the auxiliary-drive-wheel output shaft on a propeller shaft side is formed in a hollow shape and includes a fitting part configured to be spline-engaged with a joint part provided to the universal joint. The joint part is provided with a centering part which is inserted into a centering hole formed in a flange part provided to one side of the auxiliary-drive-wheel output shaft so that the joint part is centered on the auxiliary-drive-wheel output shaft. The flange part is sandwiched between a spacer and the joint part, and a bolt member is attached to a bolt hole formed in the centering part so that the propeller shaft is assembled to the auxiliary-drive-wheel output shaft.