Stepped Gear Wheel Cutting With a Ring Tool and Side Recess

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Solution Overview

Problem

Existing methods for manufacturing stepped gear wheels from a single workpiece result in a minimum width that is the sum of the widths of the two gear wheels and the distance between them, limiting the ability to reduce weight and size due to collision risks and restricted cross angles during the cutting process.

Innovation Solution

A ring-shaped cutting tool with internal cutting teeth is used, and a recess is created on the side surface of the larger gear wheel to accommodate the cutting tool, allowing for a hollow cutting operation that maximizes the cross angle and eliminates the need for gaps between the gear wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional cutting tool is used to cut gear teeth in the smaller diameter part, then the cutting operation can be performed, but the minimum width of the stepped gear wheel becomes the sum of the widths of the two gear wheels plus the distance between them, increasing the overall size and weight

Engineering Contradiction:
Improvewidth of stepped gear wheelVSAvoidcollision risk during cutting
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The cutting tool is designed as a hollow ring-shaped structure with internal cutting teeth, allowing the tool to be positioned within the recess of the larger gear wheel. This nesting configuration enables the cutting operation on the smaller gear wheel without requiring additional clearance space, thereby reducing the minimum width of the stepped gear wheel while avoiding collision between the tool and the larger gear wheel.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention introduces a recess in the radial dimension of the larger gear wheel, creating additional space in the radial direction. This dimensional change allows the cutting tool to approach the smaller gear wheel from the radial direction without collision, enabling a more compact overall width while maintaining manufacturability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the cross angle between the cutting tool and workpiece is increased to improve cutting performance, then cutting efficiency increases, but the tool may collide with the larger gear wheel, limiting the maximum achievable cross angle

Engineering Contradiction:
Improvecutting performanceVSAvoidcollision risk
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The hollow ring-shaped cutting tool nests within the recess of the larger gear wheel, providing sufficient clearance for the tool to operate at optimal cross angles without colliding with the larger gear wheel. This nesting arrangement removes the geometric constraints that previously limited the cross angle, allowing the tool to be positioned at the ideal angle for maximum cutting performance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The recess is created in the larger gear wheel before the cutting operation begins. This preliminary action prepares the workspace by removing material that would otherwise obstruct the cutting tool's path, enabling the tool to operate at higher cross angles without risk of collision during the subsequent cutting process.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If a gap of approximately 10 mm is maintained between the two gear wheels for manufacturing reasons, then the cutting operation can be performed, but the overall width and weight of the stepped gear wheel increase

Engineering Contradiction:
Improvemanufacturing feasibilityVSAvoidwidth of stepped gear wheel
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The cutting tool is nested within the recess of the larger gear wheel, allowing the cutting operation to be performed without requiring a 10 mm gap between the two gear wheels. The recess provides the necessary clearance for the tool, eliminating the need for additional spacing and thereby reducing the overall width of the stepped gear wheel while maintaining manufacturing feasibility.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of maintaining a gap in the axial direction between the two gear wheels, the invention creates clearance in the radial direction by forming a recess in the larger gear wheel. This dimensional shift allows the gear wheels to be positioned closer together axially, reducing the overall width without compromising the ability to perform the cutting operation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 method enables the production of stepped gear wheels with reduced width and potentially no gaps, minimizing size and weight while enhancing cutting performance by increasing the cross angle between the workpiece and cutting tool.

Implementation Method 1

the centre axis of the cutting tool is under an angle to the centre axis of the workpiece... the cutting edges of the end faces of the cutting teeth during the rotating motion and in a gradual feed of the cutting tool parallel to the centre axis of the workpiece at the point of engagement perform an impact movement in the direction of the gear teeth to be cut

Methodology Applied
Scientific EffectImpact movement: Impact Force

Data Source

PatentEP4028191B1Method for manufacturing a stepped gear made from one workpiece
Publication Date: 2023.07.12 VCST IND PROD
  • EP4028191B1 patent drawingFigure 1~2
  • EP4028191B1 patent drawingFigure 3~4
  • EP4028191B1 patent drawingFigure 5~7

AI summary

In a method for manufacturing a stepped gear wheel, teeth (9) are cut in a part 2A of a workpiece (11) having a smaller diameter than another part 2B of the workpiece. This cutting is performed by means of a ring shaped cutting tool (11) provided with internal cutting teeth (15). The rotating cutting tool (11) is positioned such that its centre axis (23) is under an angle to the centre axis (21) of the workpiece (2). During the rotating motion and in a gradual feed of the cutting tool (11) the cutting teeth (15) perform an impact movement. Prior to the cutting operation, in order to enable the cutting tool (11) to cut the gear teeth (9) on part 2A of the workpiece, a recess (25) is made in the larger part 2B of the workpiece to create space for the cutting tool (11).