Steering Column Gearwheel Structure to Reduce Backlash and Wear
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Solution Overview
Problem
Existing motorized steering column adjustment drives face challenges with mechanical properties conflicts in one-piece components, leading to plastic deformation and high manufacturing costs due to the need for different materials for toothings, threads, and ball tracks, which results in unacceptable backlash and wear.
Innovation Solution
A gear wheel design with a core element and axially connected bearing rings that support compressive forces outside the power flow, allowing for independent optimization of materials for the core element and bearing rings, using harder materials for bearing rings and softer materials for the core element to prevent deformation and improve mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-piece gear wheel component is used to integrate toothings, threads, and ball tracks, then device complexity is reduced, but mechanical properties conflict arises requiring different materials which leads to plastic deformation and high manufacturing costs
Solution Approach 1:
The gear wheel is divided into two separate components: a plastic core element containing the toothing and a metal bearing ring containing the ball tracks and threads. This segmentation allows each component to be optimized for its specific function with appropriate material properties, eliminating the material conflicts present in one-piece designs.
Solution Approach 2:
The invention combines plastic and metal materials in a composite structure where the plastic core element provides the toothing and the metal bearing ring provides the ball tracks and threads. This composite approach resolves the material property conflicts by allowing each material to perform its optimal function without compromise.
2Reliability
If harder materials are used for ball tracks to reduce wear, then reliability is improved, but plastic deformation occurs in one-piece components due to material property conflicts
Solution Approach 1:
The bearing ring is segmented as a separate metal component from the plastic core element. This allows the bearing ring to be made entirely of hard, wear-resistant metal material without compromising the toothing structure, thereby eliminating plastic deformation while maintaining high reliability.
Solution Approach 2:
Different material qualities are applied to different parts: the plastic core element provides the toothing with appropriate plastic properties, while the metal bearing ring provides the ball tracks and threads with hard, wear-resistant properties. Each location receives the optimal material quality for its specific function.
3Reliability
If different materials are used for toothings and ball tracks to optimize mechanical properties, then reliability is improved, but manufacturing costs increase due to multi-material processing
Solution Approach 1:
The gear wheel is segmented into two components that can be manufactured separately using optimal processes for each material, then assembled together. This segmentation reduces manufacturing complexity compared to multi-material injection molding or other complex multi-material processing methods.
Solution Approach 2:
The plastic core element and metal bearing ring are combined through assembly rather than complex multi-material processing. This merging approach allows each component to be manufactured independently with standard processes, reducing overall manufacturing costs while maintaining high reliability.
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 design enhances mechanical properties, reduces backlash, and lowers manufacturing costs by enabling the use of suitable materials for each component, resulting in a more reliable and efficient steering column adjustment system.
Implementation Method 1
a threaded spindle (52) which engages in a spindle nut (51) and has an axis (G)
Implementation Method 2
a gear wheel (7) which can be driven by the drive unit (55) to rotate about the axis (G) and which has a toothed section (72)
Implementation Method 3
two bearing rings (8) which are connected to said core element (71) and which each have a bearing surface (81) and are supported axially against one another
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a motor-adjustable steering column (1) for a motor vehicle, having a supporting unit (2) which can be attached to a vehicle body and by which an actuation unit (3) is held in which a steering shaft (32) is mounted rotatably about a longitudinal axis (L), and having an adjustment drive (5, 6) which is connected to the supporting unit (2) and to the actuation unit (3) and by which the actuation unit (3) can be adjusted relative to the supporting unit (2), wherein the adjustment drive (5, 6) has a lead screw (52, 62) which engages in a shaft nut (51) and has an axis (G), a drive unit (55, 65) and a gearwheel (7) which can be driven by the drive unit (55, 65) in a rotary manner about the axis (G) and has a toothed section (72) which is located axially between two bearing faces (81) running around coaxially to the axis (G), wherein the gearwheel (7) is connected for conjoint rotation to the shaft nut (51) or to the lead screw (62), and wherein the lead screw (52, 62) and the shaft nut (51, 61) can be driven in a rotary manner relative to each other about the axis (G) by the drive unit (55, 65). To specify a steering column with an improved adjustment drive (5, 6) with an optimised gearwheel (7) which has improved mechanical properties, the invention proposes that the gearwheel (7) has a core element (71) to which two bearing rings (8) are connected which each have a bearing face (81) and are supported axially against each other. In an adjustment drive (5, 6) according to the invention, the gearwheel (7) has a core element (71) to which two bearing rings (8) are connected which each have a bearing face (81) and are supported axially against each other.