Vehicle Steering Apparatus Reducing Backlash with Spring-Loaded Nut
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Solution Overview
Problem
Existing steering apparatuses for vehicles face challenges in adjusting the operation position of the steering wheel in the up-down direction without causing shakiness or looseness between the threaded shaft and nut member, often requiring additional parts and increasing assembly complexity and cost.
Innovation Solution
A steering apparatus with a simplified configuration that includes a motor-driven threaded shaft and a nut member with flat surface portions and a pivot shaft, supported by a link mechanism with a spring member to maintain stable engagement and reduce parts, allowing easy assembly and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slider mechanism with biasing member and pressing member is used to remove backlash, then shakiness or looseness between threaded shaft and nut member is restricted, but the number of parts increases and assembly complexity increases
Solution Approach 1:
The patent extracts and eliminates the biasing member and pressing member from the slider mechanism, retaining only the essential threaded shaft and nut member combination. This removal of unnecessary components directly reduces the number of parts while maintaining the core functionality of removing backlash through precise threading engagement.
Solution Approach 2:
The threaded shaft and nut member are designed to automatically remove backlash through their own geometric engagement without requiring external biasing members or pressing members. The self-service principle is embodied in the self-aligning threaded connection that inherently eliminates shakiness and looseness through its structural design.
2Reliability
If a slider mechanism with biasing member and pressing member is used to remove backlash, then shakiness or looseness between threaded shaft and nut member is restricted, but assembly workload increases
Solution Approach 1:
The patent removes the biasing member and pressing member from the assembly process, significantly reducing assembly workload. The simplified structure requires fewer assembly steps, less precise alignment procedures, and fewer fastening operations, making the assembly process more efficient and less labor-intensive.
Solution Approach 2:
The threaded connection design enables self-alignment and self-securing during assembly, eliminating the need for additional components to enforce engagement. The self-service characteristic reduces assembly complexity and workload by allowing the basic threaded components to perform all necessary functions automatically.
3Reliability
If resin material is used for nut and metal material is used for shaft, then tight fit at low temperatures is prevented, but deformation of resin nut occurs affecting sliding-friction torque
Solution Approach 1:
The patent modifies the geometric parameters of the threaded shaft and nut member to compensate for thermal expansion differences between resin and metal materials. By adjusting threading dimensions, pitch, and engagement geometry, the design maintains stable sliding-friction torque across temperature variations while preventing tight fit conditions at low temperatures.
Solution Approach 2:
The patent utilizes the composite material system of resin nut and metal shaft, leveraging the complementary properties of each material. The resin provides self-lubricating characteristics and thermal insulation, while the metal provides structural strength and dimensional stability. The threading design optimizes the interaction between these composite materials to maintain consistent friction torque.
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 restricts shakiness or looseness between the threaded shaft and nut member using fewer parts, ensuring a stable and cost-effective assembly process.
Implementation Method 1
a spring member arranged between the bearing portion and at least one of the two flat surface portions of the female threaded portion, and pressing the female threaded portion in a direction which is orthogonal to the axial direction of the threaded shaft
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A steering apparatus for a vehicle provided with a steering wheel (70) includes a main housing (10), a movable column member (20), a fixing bracket (30) fixing the main housing to the vehicle body, a link mechanism (4) and a drive mechanism (5) connected to the link mechanism, wherein the drive mechanism includes a motor (60), a threaded shaft (62) rotated by the motor, and a nut member (50) moving in an axial direction of the threaded shaft and threadedly engaged with the threaded shaft, the nut member includes a female threaded portion (51) including two flat surface portions (51 a, 51 b) facing each other and parallel to the threaded shaft, the nut member includes a pivot shaft portion (52) including a rotational axis (P4) orthogonal to an axis of the female threaded portion, the link mechanism includes a bearing portion (423, 424, 425) rotatably supporting the pivot shaft portion, a spring member (71, 72, 73) arranged between the bearing portion and at least one of the two flat surface portions.