Rear-Axle Steering Spindle Drive for Axial Play Elimination
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Solution Overview
Problem
Existing spindle drives with spindle threads and nut threads experience axial play due to production processes, which affects the precision and efficiency of rear axle steering systems.
Innovation Solution
Incorporating elastomeric spring elements, such as elastomer disks, to provide continuous prestress between the threaded ring and the spindle nut, eliminating axial play by using a combination of elastomer disks and an adjustment ring with a securing element to maintain prestress and prevent lubricant escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metallic spring elements are used to eliminate axial play, then the precision is improved, but the weight and manufacturing cost increase
Solution Approach 1:
The patent changes the material parameter of the spring element from metallic to elastomeric material. This parameter change maintains the functional capability of eliminating axial play through elastic deformation while significantly reducing the weight and manufacturing cost of the spring element.
Solution Approach 2:
The patent employs composite material strategy by using elastomeric material (such as rubber or plastic with elastic properties) instead of traditional metallic material for the spring element. This material substitution achieves the same prestress function with reduced weight and lower manufacturing complexity.
2Manufacturing precision
If metallic spring elements are used to eliminate axial play, then the precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the material parameter from metal to elastomer, which fundamentally simplifies the manufacturing process. Elastomeric spring elements can be produced through simpler molding or extrusion processes compared to metallic spring manufacturing, reducing both complexity and cost while maintaining the axial play elimination function.
Solution Approach 2:
The patent adopts a strategy of using inexpensive elastomeric material for the spring element, making the component cheaper to manufacture and replace if necessary. This approach prioritizes cost-effectiveness and ease of manufacture over the longevity associated with metallic components.
3Ease of manufacture
If production processes are used without additional prestress elements, then the manufacturing is simpler, but axial play occurs reducing precision
Solution Approach 1:
The patent applies preliminary action by pre-stressing the threaded connection through the elastomeric spring element before the actuator begins operation. This preliminary prestress ensures that the spindle thread and nut thread remain in continuous contact, eliminating axial play and ensuring precision from the start of operation.
Solution Approach 2:
The elastomeric spring element acts as an intermediary component between the threaded ring and the spindle nut. This intermediary element transmits and maintains the prestress force, ensuring continuous contact between the threading elements while allowing for simple manufacturing of the overall 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
The solution effectively eliminates axial play between the spindle nut and spindle, enhancing the precision and reliability of the rear axle steering system while offering weight and cost advantages over metallic spring elements.
Implementation Method 1
The at least one spring element consists of an elastomer such as a plastic with elastic properties. The elastomer can be deformed elastically and, on being deformed, exerts an elastic restoring force or prestress.
Data Source
AI summary
Actuator having a spindle drive (1) for a rear wheel steering system, including a spindle (2) with a spindle thread (2a) and a spindle nut (3) with a nut thread (3a). The spindle thread (2a) and the nut thread (3a) are designed as displacement threads and the spindle nut (3) threadedly engages with the axially displaceable spindle (2) by way of the displacement thread. The spindle thread (2a) and the nut thread (3a) are braced against one another, in the longitudinal direction of the spindle (2), by a bracing element (4). The bracing element (4) is in the form of a threaded ring having an internal thread (4a) which engages with the spindle thread (2a). The threaded ring (4) is supported relative to the spindle nut (3) by at least one spring element (5, 6), and the at least one spring element (5, 6) is made of an elastomer.