Pivoting Rotary Broach for Variable Bearing Seat Geometry

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Solution Overview

Problem

Existing rotary broaching tools for machining crankshaft bearing seats lack flexibility in varying the surface geometry, as the cutting elements are rigidly fixed, limiting the ability to adjust the bearing seat geometry during the turn-broaching process.

Innovation Solution

The cutting element is pivotably mounted on the broaching tool, allowing for controlled adjustments in its position and orientation, enabling the surface geometry on the workpiece's outer circumference to be varied during the machining process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the cutting element is rigidly fixed on the broaching tool, then the tool structure is simple and stable, but the bearing seat geometry cannot be readily varied

Engineering Contradiction:
Improvebearing seat geometry variationVSAvoidtool structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cutting element is made dynamically adjustable through a pivoting mechanism mounted on the tool carrier. The cutting element can be rotated about a cutting element axis of rotation that is transverse to the tool axis, allowing the inclination of the cutting element with respect to the tool axis to be changed during the turn-broaching process. This dynamic adjustment capability enables variation of bearing seat geometry while maintaining a relatively simple tool structure.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the cutting element position is changed during machining, then the surface geometry can be adjusted, but the control system becomes more complex

Engineering Contradiction:
Improvesurface geometry adjustmentVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSExtent of automation

Solution Approach 1:

The cutting element is designed to be pivotably mounted on the tool carrier, enabling controlled adjustments of its position and orientation during the machining process. The pivoting mechanism allows the cutting element to be rotated about an axis transverse to the tool axis, providing the necessary degrees of freedom to create customized bearing seat geometries such as cylindrical or crowned surfaces.

Inventive Principle:
Principle #15Dynamics

3Productivity

If multiple cutting elements are mounted on the tool carrier, then tool changes are eliminated, but the tool carrier complexity increases

Engineering Contradiction:
Improvemachining continuityVSAvoidtool carrier structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The tool carrier is designed as a multi-functional device that can accommodate multiple cutting elements with different functions and geometries. The tool carrier can be rotated to bring different cutting elements into the working position, allowing various process steps to be carried out without changing tools. This universal design eliminates tool changes and maintains machining continuity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3330026B1Rotary broach
Publication Date: 2022.01.05 AUDI AG
  • EP3330026B1 patent drawingFigure 1~2
  • EP3330026B1 patent drawingFigure 3~4
  • EP3330026B1 patent drawingFigure 5~6

AI summary

The invention relates to a rotary tool, in particular a rotary broaching tool for a rotary broaching machine for the finishing of a workpiece outer circumference (11) rotationally symmetrical about a workpiece axis (15), in particular a crankshaft bearing seat, with a disc-shaped tool carrier (19) which is rotatable about a tool axis (21) parallel to the workpiece axis (15) and which is equipped on its outer circumference side with at least one cutting element (23) for machining, in particular for rotary broaching, the workpiece outer circumference (11), wherein the cutting element (23) has a radially outer cutting edge (25), and wherein in a machining process, in particular a rotary broaching process, the workpiece (1) is rotated about the workpiece axis (15) and the tool carrier (19) is rotated in a direction of rotation, in particular in the opposite direction, about a feed rate (Z).The cutting element (23) removes a material allowance (Δm) from the workpiece's outer circumference (11) with its radially outer cutting edge (25). According to the invention, the cutting element (23) is pivotably mounted in the tool holder (19) to adjust the surface geometry of the workpiece's outer circumference (11). The pivot position of the cutting element (23) can be controlled and changed during the machining process.