Hub Unit Bearing Staking With Multi-Stage Preload Control

Solution Overview

Problem

The preload of hub unit bearings affects driving stability, especially in electric motor-powered vehicles, and existing methods lack specificity in adjusting preload during manufacturing.

Innovation Solution

A method involving multiple stages of staking portion formation, where axial loads are adjusted based on pre-applied and real-time information to achieve a target preload, utilizing swaging with forming dies and considering factors like fitting allowance, press-fitting load, and bearing axial gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a preload is applied to the rolling element by pressing the inner race with a staking portion, then the rigidity of the hub unit bearing is improved, but the manufacturing precision of the preload cannot be controlled

Engineering Contradiction:

Improverigidity of hub unit bearingVSAvoidpreload adjustment precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The staking process is divided into multiple stages with different forming die shapes. The first stage uses a forming die with a larger swing angle to create an intermediate staking portion, while the second stage uses a forming die with a smaller swing angle to achieve the final precise preload. This segmentation allows control over the preload magnitude at each stage, enabling precise manufacturing of the target preload value.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention dynamically adjusts the shape parameters of the forming die between stages. Specifically, the swing angle of the forming die is changed from a larger angle in the first stage to a smaller angle in the second stage. This dynamic adjustment of processing parameters enables precise control over the staking portion formation and consequently the preload applied to the rolling elements.

Inventive Principle:

Principle #15Dynamics

2Ease of manufacture

If swaging is performed in one stage, then the manufacturing process is simple, but the preload cannot be adjusted to a target value

Engineering Contradiction:

Improvesimplicity of staking processVSAvoidpreload control accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The staking process is divided into multiple stages with different forming die shapes. The first stage uses a forming die with a larger swing angle to create an intermediate staking portion, while the second stage uses a forming die with a smaller swing angle to achieve the final precise preload. This segmentation allows control over the preload magnitude at each stage, enabling precise manufacturing of the target preload value.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the shape parameters of the forming die between stages, specifically the swing angle. The first stage uses a forming die with a larger swing angle, while the second stage uses a forming die with a smaller swing angle. This parameter change enables precise control over the staking portion formation and consequently the preload applied to the rolling elements.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the swing angle of the forming die is large, then the staking portion is formed quickly, but the load applied to the inner race becomes unbalanced

Engineering Contradiction:

Improvestaking portion formation speedVSAvoidload balance on inner race

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The staking process is divided into multiple stages with different forming die shapes. The first stage uses a forming die with a larger swing angle to create an intermediate staking portion, while the second stage uses a forming die with a smaller swing angle to achieve the final precise preload. This segmentation allows control over the preload magnitude at each stage, enabling precise manufacturing of the target preload value.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention dynamically adjusts the shape parameters of the forming die between stages. Specifically, the swing angle of the forming die is changed from a larger angle in the first stage to a smaller angle in the second stage. This dynamic adjustment of processing parameters enables precise control over the staking portion formation and consequently the preload applied to the rolling elements.

Inventive Principle:

Principle #15Dynamics

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

Enables precise adjustment of preload to enhance driving stability by ensuring consistent and optimal load distribution in hub unit bearings.

Implementation Method 1

a staking portion forming step of forming the staking portion by applying a load to the axial inner end portion of the hub body

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS12103065B2Staking assembly manufacturing method, hub unit bearing manufacturing method, and vehicle manufacturing method

Publication Date: 2024.10.01 NSK LTD

AI summary

A method of manufacturing a hub unit bearing (1) includes the step of applying an axial load to a shaft end of a hub body (21) so that a staking portion (26) for inner races (22a, 22b) is formed in the hub body (21). The load is adjusted based on at least one of first information acquired before applying the load and second information acquired while applying the load.