C-Section Inner Cam Honing via Stacked Workpiece Balancing
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Solution Overview
Problem
Existing honing methods struggle to accurately grind arcuately shaped inner circumferential surfaces with discontinuous portions, leading to reduced machining precision due to uneven grinding and axis deviations.
Innovation Solution
A honing method involving the stacking and precise positioning of workpieces to balance machining loads, ensuring that the grindstones apply consistent pressure orthogonal to the axial centers, thereby preventing inclination and load fluctuations, allowing for high-precision grinding of arcuately shaped surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grindstones are brought into contact with inner circumferential surfaces of stacked workpieces with different circumferential groove positions, then productivity is improved through simultaneous honing of multiple workpieces, but machining precision deteriorates due to intermittent grinding and continuous machining load fluctuations
Solution Approach 1:
The workpieces are segmented into different groups based on their groove positions. Workpieces are stacked in multiple layers with each layer having workpieces with the same circumferential groove position, allowing continuous grinding without load fluctuations while maintaining high productivity through simultaneous processing of multiple workpieces.
2Ease of manufacture
If grindstones are narrower than the discontinuous portion width, then the grindstones can be brought into contact with the inner circumferential surface, but machining accuracy reduces due to deviation between workpiece axis and honing head rotation center
Solution Approach 1:
The stacking arrangement creates a balanced gravitational and force field where the combined center of gravity of the stacked workpieces aligns with the rotational axis of the honing head. This equipotential arrangement eliminates deviations between the workpiece axis and honing head rotation center, maintaining machining accuracy while enabling grindstone contact.
3Productivity
If multiple workpieces are stacked with different circumferential groove positions, then productivity increases through parallel processing, but machining load fluctuates continuously causing precision loss
Solution Approach 1:
Workpieces are segmented into groups with identical circumferential groove positions within each layer. This segmentation ensures that all workpieces in a layer present the same grinding resistance to the grindstones, eliminating continuous load fluctuations while maintaining high productivity through multi-layer parallel processing.
Solution Approach 2:
The stacking creates a periodic structure where identical workpiece configurations repeat at regular intervals. This periodic arrangement ensures that machining loads are applied in a consistent, repeating pattern rather than continuously fluctuating, stabilizing the grinding process while enabling simultaneous processing of multiple workpieces.
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 high-precision grinding of arcuately shaped inner circumferential surfaces with discontinuous portions, achieving a circularity deviation of less than 10 μm and improving machining accuracy and efficiency for mass-produced inner cams with C-shaped cross sections.
Implementation Method 1
a plurality of rod-shaped grindstones, which extend along the axial direction, are attached at intervals along the circumferential direction thereof. The honing head is inserted into the interior of a workpiece so that the direction of extension of the grindstones lies along an axial center, and while the grindstones are rotated, grinding is enabled by placing the grindstones in contact with the workpiece and applying an appropriate surface pressure to the inner circumferential surface of the workpiece.
Data Source
AI summary
An inner cam has a substantially C-shaped cross section, an arcuately shaped inner circumferential surface of which is ground with high precision by such a honing method. The inner circumferential surface has a discontinuous portion. The honing method includes a fixing step and a grinding step. A plurality of inner cams, in which openings are provided between both ends thereof in the circumferential direction, are stacked, and the arcuately shaped inner circumferential surfaces thereof are subjected to grinding. In the fixing step, the relative positions of the plurality of inner cams are fixed such that a resultant force against the inner cams arranged on both end sides in the stacking direction, and a resultant force against the inner cams arranged on a central side in the stacking direction are opposed to each other mutually at a center location of the stacking direction.