Cylinder Block Press-Fitting Portion Rigidity Design
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Solution Overview
Problem
In V-type internal combustion engines, the rigidity deviation in press-fitting portions between cylinder banks can lead to stress concentration and plastic deformation when sealing members are press-fit, due to uneven thickness distribution in the press-fitting portions.
Innovation Solution
The cylinder block design features a press-fitting portion with a thinner thickness on the side closer to the opening for the first bank and a thicker thickness on the side closer to the opening for the second bank, ensuring uniform rigidity along the periphery and reducing weight, thereby inhibiting stress concentration and plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the press-fitting portion has uniform thickness, then manufacturing is simpler, but rigidity deviation occurs causing stress concentration and plastic deformation
Solution Approach 1:
The press-fitting portion is designed with non-uniform thickness distribution, where the thickness varies in the radial direction of the hole. Specifically, the thickness at portions connected to different banks is made different to compensate for rigidity deviations. This local variation in geometric quality ensures uniform rigidity throughout the press-fitting portion, preventing stress concentration and plastic deformation while maintaining manufacturing feasibility.
2Strength
If the press-fitting portion thickness is increased to improve rigidity, then structural strength improves, but weight increases
Solution Approach 1:
Instead of uniformly increasing the thickness of the press-fitting portion, the invention applies local thickness variation. The thickness is optimized at specific portions (connected to different banks) to achieve uniform rigidity distribution. This approach provides the necessary structural strength and rigidity only where needed, avoiding unnecessary weight increase throughout the entire component.
3Stability of the object's composition
If the press-fitting portion has non-uniform thickness, then rigidity uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The invention changes the geometric parameter (thickness) of the press-fitting portion in a controlled manner. By varying the thickness in the radial direction of the hole at specific portions, the rigidity uniformity is achieved. This parameter modification creates a relatively simple geometric form that can be manufactured using conventional processes, avoiding excessive complexity while achieving the desired rigidity distribution.
Data Source
AI summary
A cylinder block includes a first bank, a second bank, and a press-fitting portion. The first bank and the second bank are arranged in positions offset from each other in a cylinder arrangement direction. The press-fitting portion is provided straddling a first end surface of the first bank and a second end surface of the second bank. The press-fitting portion has a hole. The first end surface protrudes in a direction in which the press-fitting portion protrudes in the cylinder arrangement direction, with respect to the second end surface. A thickness of the press-fitting portion in a radial direction of the hole at a first portion that is connected to the first end surface is thinner than a thickness of the press-fitting portion in the radial direction of the hole at a second portion that is connected to the second end surface.