Helical Gear Cutting with Synchronized Rolling Contact
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Solution Overview
Problem
Conventional gear manufacturing methods, such as form rolling, are time-consuming and require repeated die pressing, leading to inefficiencies and material extrusion issues.
Innovation Solution
A gear manufacturing method involving a workpiece rotated around a first axis and a tool with annularly arranged cutting blades rotated around a second axis, where the workpiece and tool move relative to each other in parallel, forming helical teeth through synchronized movement, reducing material removal time and avoiding extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If form rolling method is used to manufacture gear, then the gear can be manufactured with material flow forming, but the process requires repeated die pressing which takes time and causes material extrusion issues
Solution Approach 1:
The gear manufacturing process is segmented into two distinct operations: (1) forming the gear blank with basic tooth shape using a forming die, and (2) finishing the tooth profile precision using a separate shaving tool. This segmentation allows each tool to be optimized for its specific function, improving overall manufacturing efficiency and avoiding the time-consuming repeated pressing of conventional form rolling
Solution Approach 2:
The gear blank is pre-formed with approximate tooth shape and dimensions using a forming die before the final precision shaving operation. This preliminary action removes the need for repeated die pressing to achieve the final shape, as the bulk material removal is completed in the first forming stage
2Manufacturing precision
If form rolling method is used to manufacture gear, then the gear can be manufactured with material flow forming, but the process takes time due to repeated die pressing
Solution Approach 1:
The manufacturing process is divided into forming and shaving stages, where the forming stage creates the gear blank with acceptable precision, and the shaving stage provides the final high-precision tooth profile. This eliminates the need for repeated pressing cycles while maintaining high precision through the dedicated shaving operation
Solution Approach 2:
The shaving tool continuously removes material from the gear blank in a single passing operation, maintaining continuous cutting action throughout the tooth profile formation. This continuous process replaces the intermittent repeated pressing of form rolling, significantly reducing manufacturing cycle time while ensuring consistent precision
3Productivity
If conventional form rolling is used, then the gear can be manufactured, but material extrusion requires additional removal processing
Solution Approach 1:
The forming and finishing operations are separated, allowing the forming die to create the gear blank with minimal material waste, while the shaving tool precisely removes only the necessary excess material to achieve final dimensions. This segmentation reduces overall material waste compared to conventional form rolling where repeated pressing causes significant extrusion and waste
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 allows for the efficient, one-time formation of precise helical gears with reduced heat generation and material processing time, while eliminating the need for extruded material removal, thus enhancing manufacturing speed and precision.
Implementation Method 1
making an inner peripheral side of the tool contact with an outer peripheral surface of the workpiece, and removing a material of the workpiece at a contacted portion by the relative movement between the tool and the workpiece
Implementation Method 2
at a predetermined one point on the target outline, makes rolling contact with the target outline without sliding relative to the target outline, and in an area other than the predetermined one point, rotates relative to the target outline while sliding relative to the target outline
Data Source
AI summary
A method for manufacturing a gear includes rotating a workpiece around a first axis, and rotating a plurality of cutting blades arranged annularly around a second axis skew to the first axis around the second axis. The method further includes, while causing the workpiece and the cutting blades to perform relative movement in a direction parallel to the first axis at a speed synchronized with a rotational speed of the workpiece, forming a helical tooth groove in an outer peripheral surface of the workpiece by the cutting blades. In a cross section perpendicular to the first axis, a diameter of a rolling circle in which an outline of the cutting blades and a target online of the gear make rolling contact with each other is larger than a diameter of a tooth depth center circle.