Honing Tool Asymmetrical Bore Shaping for Cylinder Sealing
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Solution Overview
Problem
Conventional honing processes for cylinder blocks in reciprocating engines face challenges in reducing friction losses, oil consumption, and blow-by due to cylinder distortions and asymmetrical bore shapes, which affect the sealing function of piston rings and lead to performance degradation.
Innovation Solution
A honing tool with an annular cutting group and expandable guide rails is used to produce bore shapes with varying diameters, ensuring high cutting performance with low pressure forces, preventing tilting, and maintaining consistent contact with the bore surface, allowing for the creation of symmetrical bore shapes like bottle or cone shapes that reduce friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional honing processes are used to machine cylinder running surfaces, then adequate lubrication and low frictional resistance can be achieved, but cylinder distortions and asymmetrical bore shapes occur during assembly and operation, impairing the sealing function of piston rings
Solution Approach 1:
The patent applies asymmetry by intentionally creating asymmetrical bore shapes during honing that correspond to the expected distortion pattern of the cylinder block. The honing tool is designed to produce a bore shape that deviates from a perfect circle, with specific asymmetrical features that will be corrected when the block distorts during assembly and operation, thereby achieving symmetrical dimensions in the final state and ensuring proper piston ring sealing.
2Productivity
If the axial length of cutting material bodies is reduced to improve cutting performance with low pressure forces, then material removal efficiency increases, but the stability and control of the honing tool during operation may be compromised
Solution Approach 1:
The patent applies segmentation by dividing the cutting material bodies into multiple discrete segments arranged circumferentially around the honing tool. This segmentation allows each cutting segment to operate independently with optimized axial length for efficient material removal, while the distributed arrangement across the circumference provides balanced forces and enhanced tool stability during operation.
3Manufacturing precision
If form honing is used to create negative form of distortion errors during processing, then ideal circular cylinder shape can be achieved after assembly, but the honing process complexity and device requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-distorting the bore shape during the honing process to compensate for expected future distortions. The honing tool is configured to create a bore shape that intentionally deviates from circularity, with the deviation pattern matching the anticipated distortion of the cylinder block during assembly and operation, so that the final dimensions become ideal circular cylinder shape without requiring complex real-time adjustment mechanisms.
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
The solution effectively reduces friction losses, oil consumption, and blow-by by maintaining a consistent seal and minimizing material removal distances, ensuring high-quality surface finishes and improved engine performance.
Implementation Method 1
The cutting material bodies attached to the honing tool are pressed against the inner surface to be machined via a cutting material body infeed system with an infeed force acting radially to the tool axis. During honing, a cross-hatch pattern typical of honing occurs on the inner surface with crossing traces of processing
Data Source
Figure 1~3
Figure 2A~2B
Figure 4A~4B
AI summary
A honing tool for machining an inner surface of a bore in a workpiece with the aid of at least one honing operation comprises a tool body (210) which defines a tool axis (212), an expandable annular cutting group (220) having a plurality of cutting material bodies distributed around the circumference of the tool body, the axial length of said cutting material bodies, measured in the axial direction, being less than an effective outside diameter of the cutting group with the cutting material bodies fully retracted, wherein the cutting material bodies are arranged in an end region, remote from the spindle, of the tool body and are infeedable radially with respect to the tool axis by means of a cutting group infeed system assigned to the cutting group; and an expandable guiding group (300) having a plurality of guiding strips (320) distributed around the circumference of the tool body, said guiding strips (320) being arranged on the tool body partially or fully between the annular cutting group (220) and a spindle-side coupling structure of the honing tool and being radially infeedable independently of the cutting material bodies by means of a guiding group infeed system. The honing tool can be used in particular for honing cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines.