Spherical Bulb Coupling for Tiltable Steering Column
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Solution Overview
Problem
Conventional cardan joints in tiltable steering columns are limited by a maximum angle of 45°, are complex to assemble, require additional damping elements to manage vibrations, and are prone to oxidation, leading to increased costs and assembly complications.
Innovation Solution
A spherical bulb-shaped coupling with a damping sheath element and antifriction jacket mediates torque transfer between two shafts, eliminating the need for a cardan joint and integrating damping within the coupling, allowing for stable rotation and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional cardan joint is used to transmit rotational movement in a tiltable steering column, then the transmission of rotational movement between shafts with incidence angle is achieved, but the maximum potential angle is limited to 45° and the construction complexity increases
Solution Approach 1:
The cardan joint is divided into two separate universal joints that can be independently positioned and adjusted. This segmentation allows each joint to handle a portion of the angular regulation, enabling the steering column to achieve tilt angles greater than 45° while maintaining manageable complexity in each individual joint component
Solution Approach 2:
The solution introduces an additional dimensional aspect by using two cardan joints arranged in series rather than one joint, effectively distributing the angular regulation across multiple stages. This dimensional approach to angular transmission allows the system to exceed the 45° limitation of a single joint while keeping each joint's complexity within acceptable bounds
2Reliability
If a conventional cardan joint is used in a tiltable steering column, then the rotational movement transmission is achieved, but additional damping elements are required to manage vibrations, increasing encumbrance and assembly complications
Solution Approach 1:
The damping function is merged with the cardan joint structure itself. The universal joints are designed to inherently absorb and dampen vibrations through their spherical geometry and clearance characteristics, eliminating the need for separate damping elements and reducing assembly complexity
Solution Approach 2:
The cardan joint structure provides its own vibration damping capability through the natural characteristics of the spherical joints and their clearance design. The joints self-regulate vibrations without requiring external damping components, simplifying the overall system
3Reliability
If a conventional cardan joint is used in aggressive environments, then the rotational movement transmission is achieved, but oxidation problems occur affecting reliability
Solution Approach 1:
The cardan joint components are constructed using composite materials or coated with protective layers that combine the mechanical properties needed for rotational transmission with corrosion-resistant characteristics. This allows the joint to maintain reliability in aggressive environments while performing its primary function
4Reliability
If a conventional cardan joint with additional damping element is used, then vibration damping is improved, but the encumbrance and cost increase
Solution Approach 1:
The damping function is integrated into the cardan joint structure itself rather than being provided by a separate component. The universal joints' spherical geometry and inherent clearance provide vibration absorption capabilities without requiring additional damping elements, thereby reducing the overall weight and encumbrance of the steering column assembly
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
This solution simplifies construction, reduces costs, and enhances oxidation resistance while effectively managing vibrations and noise, providing a versatile and compact coupling that maintains quality without additional mechanical components.
Implementation Method 1
The first upper half-coupling 32 is sheathed (completely isolated) with respect to the other components, by means of a sheath element 34 which envelops it
Implementation Method 2
The sheath element 34 is in turn covered by an antifriction jacket 35
Data Source
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AI summary
A coupling for the transmission of the rotational movement in a tiltable steering column, wherein said column comprises a first movable part of the chassis (16) and a second underlying fixed part (19) of the chassis, a rod element (13), integral with a handle, positioned in the centre of a steering wheel of a vehicle, being situated in said first part of the movable chassis (16), and a shaft (31) connected to a hydraulic power steering system, being positioned inside said second underlying fixed part (19) of the chassis, the coupling effecting the transmission of the rotational movement between two rotating shafts defined by a tubular element (15) and a lower shaft (31) and the regulated tilted positioning between the first movable part (16) of the chassis and the second underlying fixed part (19) of the chassis, wherein the coupling (30) comprises a first upper half-coupling (32) coupled with the end of the tubular element (15) and a second lower half-coupling (33) integral with the lower shaft (31), which form a complete spherical bulb-shaped coupling in which said first upper half-coupling (32) is sheathed by means of a sheath element (34) which envelops it in one of its coupling portions to the second lower half-coupling (33), the sheath element (34) being a rubber damping element.