Rotary Press Guide Teeth Prevent Roll Sliding During Bearing Spline Formation

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Solution Overview

Problem

Existing methods for manufacturing bearing units, particularly those involving rotary press devices, face challenges in achieving precise formation of face splines, leading to potential damage and reduced lifespan due to sliding during rotary forging, which can result in radial stripes and exfoliation of the caulking section.

Innovation Solution

A method and rotary press device that restricts the motion of the roll around the central axis during rotary forging by using guide teeth or an elastic member, preventing sliding and ensuring precise formation of the face spline on the hub-side caulking section, thereby maintaining the meshed state between the hub and outer wheel splines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rotary forging is performed without restricting roll motion, then the face spline can be formed on the caulking section, but sliding occurs during processing causing radial stripes and exfoliation damage

Engineering Contradiction:

Improveface spline formationVSAvoidsurface quality of face spline

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Guide teeth are introduced as an intermediary mechanism between the roll and the workpiece. These guide teeth engage with corresponding teeth on the roll to control and restrict the roll's rotational motion, preventing unwanted sliding while allowing the face spline forming process to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a static roll position to a dynamically controlled motion system. The roll is allowed to rotate but its motion is dynamically restricted by the guide teeth mechanism, which permits controlled rotation for spline formation while preventing excessive sliding that causes damage

Inventive Principle:

Principle #15Dynamics

2Productivity

If the roll is allowed to rotate freely during rotary forging, then the processing can be completed, but the teeth of the roll and workpiece do not mesh properly causing imprecise spline formation

Engineering Contradiction:

Improveprocessing completionVSAvoidspline meshing accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Guide teeth serve as a mediating mechanism that ensures proper meshing between the roll teeth and workpiece. By engaging these guide teeth, the system maintains synchronized rotation and proper tooth alignment, ensuring precise spline formation while completing the processing operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide teeth mechanism provides mechanical feedback to control roll motion. As the roll rotates, the guide teeth engage and disengage in a controlled manner, providing real-time feedback that maintains proper meshing accuracy throughout the face spline forming process

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If guide teeth are introduced to restrict roll motion, then sliding is prevented and spline quality improves, but the device complexity increases

Engineering Contradiction:

Improveface spline qualityVSAvoidrotary press device structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The guide teeth mechanism is segmented into discrete teeth rather than a continuous constraint system. This segmentation allows the complexity to be distributed and managed in modular units, making the overall device more manageable while achieving the precision goal

Inventive Principle:

Principle #1Segmentation

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

Prevents the formation of radial stripes on the face spline, reduces the risk of caulking section damage, and extends the lifespan of the bearing unit by ensuring accurate and stable spline engagement.

Implementation Method 1

a caulking section formed by plastically deforming a cylindrical portion formed on the other end portion of the hub main body in the axial direction outward in a radial direction

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the hub-side face spline serving as a concavo-convex section in the circumferential direction is formed by performing rotary forging that rotates the roll about the central axis of the hub main body in a state in which a processing surface of the roll inclined with respect to the central axis of the hub main body and rotatably (autorotatably) supported about the central axis thereof is pressed against the other end surface of the caulking section in the axial direction

Methodology Applied

Scientific EffectRotary forging:

Implementation Method 3

the other end surface of the inner wheel in the axial direction is surrounded by guide teeth serving as a concavo-convex section in the circumferential direction, and the guide teeth and some of teeth formed on the processing surface of the roll (for example, an outer half section in the radial direction) are meshed with each other

Methodology Applied

Scientific EffectMechanical engagement:

Data Source

PatentEP3266536B1Method for manufacturing bearing unit, and rotary press device

Publication Date: 2020.11.25 NSK LTD

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AI summary

A rotary press device (33) includes a restriction section (36) configured to restrict a motion of a roll (30) around a central axis of a roll (30) against movement of the roll (30) around a central axis of a hub main body (8) during rotary forging. In an example, the restriction section (36) has guide teeth (44) meshed with teeth formed on a processing surface of the roll (30).