Rack Bar Support Yoke With Elastic Compensation
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Solution Overview
Problem
Conventional rack bar supporting devices in vehicle steering apparatuses experience increased operational friction and noise due to wear of the support yoke, leading to varying clearance between the rack bar and pinion gear, which reduces the supporting force and deteriorates the driver's steering feeling.
Innovation Solution
The proposed solution involves a rack bar supporting device with wedge-shaped yoke seats and elastic supports that maintain a constant clearance between the rack bar and support yoke, utilizing a yoke plug and elastic member to ensure consistent contact and reduce friction, featuring mounting grooves and an adjustment mechanism to compensate for wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the support yoke is made of plastic material softer than the rack bar to prevent wear, then the rack bar wear is reduced, but the support yoke wears faster leading to increased clearance and reduced supporting force
Solution Approach 1:
The support yoke is divided into two functional parts: a hard wear-resistant contact surface (first surface) that contacts the rack bar, and a softer body material that provides elastic deformation capability. This segmentation allows each part to perform its specific function optimally without the trade-off present in the conventional single-material design.
Solution Approach 2:
The support yoke employs local quality by making only the contact surface (first surface) harder than the rack bar while keeping the body material softer. This localized hardness distribution ensures wear resistance at the critical contact point while maintaining overall elastic properties for clearance compensation.
2Reliability
If the support yoke is made harder than the rack bar to increase wear resistance, then the support yoke wear is reduced, but the rack bar wears faster leading to increased clearance and reduced supporting force
Solution Approach 1:
The support yoke is segmented into a hard first surface for rack bar contact and a softer body material. This segmentation reverses the conventional approach by placing the hardest material only where needed (at the contact surface) rather than making the entire yoke hard, thereby protecting the rack bar while ensuring yoke durability.
Solution Approach 2:
Local quality is applied by concentrating the hard material property only at the first surface that contacts the rack bar, while the rest of the yoke body maintains softer elastic properties. This localized hardness optimization protects the rack bar from wear while ensuring the yoke's overall structural integrity and durability.
3Power
If elastic support is used to compensate for clearance between rack bar and pinion gear, then force transmission efficiency is improved, but operational friction and noise increase due to support yoke wear
Solution Approach 1:
The elastic support function is localized to specific regions of the support yoke (second and third surfaces) that are designed with softer material properties. This localized softness reduces friction and noise at contact points while the hard first surface maintains efficient force transmission, thereby resolving the contradiction between power transmission and harmful operational effects.
4Object-generated harmful factors
If the support yoke and rack bar maintain constant clearance, then operational friction and noise are reduced, but the device complexity increases due to additional mounting grooves and adjustment mechanisms
Solution Approach 1:
The mounting grooves for elastic supports are merged into the body of the support yoke rather than being separate components. This integration simplifies the overall device structure while maintaining the constant clearance function, as the elastic supports are housed within the yoke's own structure rather than requiring external mounting features.
Solution Approach 2:
The support yoke is designed with multi-functionality by incorporating both the structural support function and the elastic support function within a single component. The mounting grooves are formed directly in the yoke body, making the yoke itself serve as both the structural element and the housing for elastic supports, thereby reducing device complexity while maintaining constant clearance.
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 configuration reduces operational friction and noise, maintains a consistent supporting force, and enhances the driver's steering experience by maintaining a constant clearance and efficient force transmission between the rack bar and pinion gear.
Implementation Method 1
an elastic support 263 arranged behind the support yoke 260 to push the support yoke 260 with a predetermined pressure
Implementation Method 2
the yoke plug 265 is positioned behind the elastic support 263 to support the elastic support 263
Implementation Method 3
The support yoke 260 is caused to be frictionally slid against the rear side of the rack bar 140
Data Source
AI summary
A rack bar supporting device for a vehicle steering apparatus, having a clearance between the rack bar and a support yoke can be kept always constant when the vehicle steering apparatus is operated, which makes it possible to reduce operational friction and noise, to maintain the supporting force of the support yoke and the rack bar to be constant for a long time, and to improve a steering feeling of a driver.