Rolling Bearing Unit Caulking via Motor Current Feedback

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Solution Overview

Problem

Existing methods for manufacturing rolling bearing units for wheels lack optimization in caulking processing time, leading to potential overloading or prolonged processing due to variations in workpiece manufacturing errors and properties.

Innovation Solution

A method involving a rotating type caulking apparatus where a roll is inclined and rotated against a cylindrical section to form a caulking section, with the caulking process terminated based on detected rotational torque or current values, ensuring consistent preload application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the caulking process uses a fixed predetermined time for all workpieces, then the manufacturing process is simple to control, but the processing time cannot be optimized for each individual workpiece leading to potential overloading or prolonged processing

Engineering Contradiction:
Improvecaulking processing time optimizationVSAvoidprocess control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies feedback control by detecting the rotational torque or current values during the caulking process in real-time, and using this information to determine when to terminate the caulking operation. This allows the processing time to be dynamically adjusted based on the actual state of each workpiece, optimizing the caulking process for each individual component while maintaining precise control through measurement and feedback mechanisms.

Inventive Principle:
Principle #23Feedback

2Productivity

If the caulking process is terminated based on real-time torque or current detection, then the processing time is optimized for each workpiece, but the measurement and control system becomes more complex

Engineering Contradiction:
Improvecaulking processing efficiencyVSAvoidtorque and current measurement complexity
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs the self-service principle by utilizing the existing motor's current detection capability to indirectly measure the rotational torque during caulking. Instead of requiring a separate torque sensor, the system leverages the motor controller's inherent current measurement functions, allowing the caulking process to be optimized through readily available electrical parameters that directly reflect the mechanical loading conditions.

Inventive Principle:
Principle #25Self-service

3Reliability

If the roll is inclined and rotated during caulking, then the caulking section is formed more effectively, but the apparatus complexity increases compared to a stationary pressing method

Engineering Contradiction:
Improvecaulking section formation qualityVSAvoidcaulking apparatus complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by transitioning from a static pressing method to a dynamic caulking process where the roll is inclined at a specific angle and rotated during the caulking operation. This rotational motion, combined with the inclined configuration, enables more effective material flow and deformation, resulting in superior caulking section formation. The dynamic approach leverages the rotational movement to distribute the forming forces more uniformly throughout the caulking process.

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

This approach optimizes the caulking processing time for each workpiece by determining the termination condition through measured rotational torque or current values, preventing excessive shortening or lengthening of processing time.

Implementation Method 1

a caulking section formed by plastically deforming a cylindrical section, installed on an inner end portion of the hub main body in the axial direction (a portion of the cylindrical section protruding from an inner end opening of the inner ring in the axial direction), outward in a radial direction

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3306125B1Manufacturing method for rolling bearing units for wheel support
Publication Date: 2021.05.12 NSK LTD
  • EP3306125B1 patent drawingFigure 1
  • EP3306125B1 patent drawingFigure 2(A)~2(F)
  • EP3306125B1 patent drawingFigure 3

AI summary

A method of manufacturing a rolling bearing unit for supporting a wheel includes detecting a current value flowing through an electric motor (19) configured to drive a roll (22) and determining a time to terminate a caulking process on the basis of the detected value when a caulking section (13) is formed by pressing the roll (22), inclined with respect to a central axis of a hub main body (7) and supported in a rotatable state about a central axis of the roll, against a cylindrical section (12), installed on an inner end portion of the hub main body (7) in the axial direction, while the roll (22) is rotated about the central axis of the hub main body (7).