Double Disc Surface Grinding Work Holding Section
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Solution Overview
Problem
Double disc surface grinding machines face challenges in achieving high grinding accuracy for large, thin-walled annular works due to warp-induced vibrations and instability when grinding both surfaces simultaneously, particularly for piston rings and bearing rings, as the works tend to move spontaneously with respect to the rollers, leading to reduced accuracy and increased flailing during rotation.
Innovation Solution
A double disc surface grinding machine design where the inner circumferential surface of the work is held by a work holding section that moves integrally with the work, reducing movement between the work and the rollers, and allowing for radial position adjustment of holding members to securely grasp the work at multiple points, thereby minimizing warp-induced vibrations and ensuring stable holding regardless of the work's diameter or shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the work is sandwiched and supported rotatably by the rollers in a conventional double disc surface grinding machine, then the work can be held and rotated during grinding, but the work moves spontaneously with respect to the rollers in the axial thickness direction, causing instability and reduced grinding accuracy
Solution Approach 1:
A work holding section is introduced as an intermediary component between the work and the rollers. This holding section includes holding members that contact and secure the work, preventing spontaneous movement during grinding. The holding section acts as a mediator that stabilizes the work without interfering with the grinding operation, thereby maintaining both reliability and manufacturing precision.
Solution Approach 2:
The work holding section is designed to be movable and adjustable, allowing it to adapt to different workpiece sizes and shapes. The holding members can be positioned radially to match the work inner circumferential surface, enabling stable holding while accommodating variations in work geometry. This dynamic adjustment capability ensures consistent grinding accuracy across different work types.
2Ease of operation
If the work has a warp (mountain-shape or s-shape) on its surfaces to be ground, then the work can be held by the rollers, but the warp causes the portion not sandwiched by the grinding wheels to vibrate, flail or violently swing, interfering with smooth rotation and reducing grinding accuracy
Solution Approach 1:
The work holding section serves as an intermediary that supports the work at multiple points around its inner circumference, rather than relying solely on the grinding wheels to hold the work. This distributed support system prevents warping-induced flailing by maintaining stable contact points throughout the work rotation, thereby improving grinding accuracy while preserving ease of operation.
Solution Approach 2:
The work holding function is segmented into multiple holding members distributed around the work inner circumference. Instead of a single point contact, the segmented holding members provide distributed support that counteracts warp-induced vibrations and prevents violent swinging, enabling smooth rotation and high precision grinding.
3Device complexity
If all three rollers (in-hole driven roller, drive roller, and outer circumferential driven roller) are substantially aligned on a single straight line, then the machine structure is simplified, but the work supporting points are eccentrically-located and it is not possible to hold the work stably
Solution Approach 1:
The work holding section acts as an intermediary that decouples the roller alignment from the work holding function. By introducing this intermediate holding mechanism, the rollers can remain in a simplified linear arrangement while the holding section provides the necessary stable support points, thus maintaining both device simplicity and work holding reliability.
4Adaptability or versatility
If the work diameter is larger and the work wall thickness (radial thickness) is thinner, then the work can be ground, but the work's distortion/warp is greater and the work is less rigid, making it more difficult to grind
Solution Approach 1:
The work holding section is designed with adjustable holding members that can be positioned radially to match different work inner circumferential surface radii. This dynamic adjustability allows the holding section to provide optimal support for works of various sizes and thicknesses, compensating for reduced rigidity in thin-walled large-diameter works and enabling successful grinding of a wide range of workpieces.
Solution Approach 2:
The work holding section provides universal support functionality that adapts to different workpiece geometries. By making the holding members movable and adjustable, the same holding section can effectively support both thin-walled large-diameter works and thicker smaller works, thereby enhancing the machine's adaptability while compensating for variations in work rigidity.
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
A double disc surface grinding machine (10) includes work holding section (65) for holding an inner circumferential surface of an annular work (W) at a plurality of locations. The work holding section (65) includes a plurality of holding members (66) extending radially as viewed from a rotation shaft (46). Each holding member (66) is movable outward and inward radially of the rotation shaft (46), and is contactable to the inner circumferential surface of the work (W). The position adjustment section (76) connects the rotation shaft (46) and the work holding section (65) with each other, and adjusts a position of the work holding section (65) in the radial direction of the rotation shaft (46). While the inner circumferential surface of the work (W) is held by the work holding section (65), the rotation shaft (46), the position adjustment section (76), the work holding section (65) and the work (W) are rotated integrally with each other around the rotation shaft (46). Part of the rotating work (W) is sandwiched by a pair of grinding wheels (16a), (16b) to grind two main surfaces of the work (W).