Fluid Pressure Cylinder Head Bolt Load Distribution
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Solution Overview
Problem
The existing hydraulic cylinder fixing structure concentrates tensile loads on head bolts at the boundary between regions with and without head bolts, leading to uneven load distribution and increased cylinder head size.
Innovation Solution
The fluid pressure cylinder employs a head bolt arrangement where head bolts are evenly spaced at angular intervals around the circumference, creating a contact region and a non-contact region to distribute the tensile load evenly, with the non-contact region within the second region to reduce stress on head bolts at the ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If head bolts are disposed to avoid the pipe attachment seat, then the pipe attachment function is ensured, but the tensile load becomes concentrated on head bolts at the boundary region, requiring greater rigidity and increasing cylinder head size
Solution Approach 1:
The invention applies local quality by creating a non-contact region between the piston and cylinder head in the second region (where head bolts are not disposed). This localized modification of the contact characteristic redistributes the tensile load more evenly across all head bolts, preventing concentration at boundary regions while maintaining the pipe attachment function in the first region.
2Strength
If head bolts are evenly spaced at equal angular intervals, then the load distribution becomes more uniform, but the pipe attachment seat location constraints create regions where head bolts cannot be disposed
Solution Approach 1:
The invention segments the circumferential space into two distinct regions: a first region where head bolts are disposed at equal angular intervals to achieve uniform load distribution, and a second region (non-contact region) where head bolts are not disposed to avoid interfering with the pipe attachment seat. This segmentation allows both uniform load distribution and pipe attachment functionality to coexist.
3Strength
If the cylinder head size is increased to provide greater rigidity for bearing concentrated loads, then the load bearing capacity increases, but the overall device size and weight increase
Solution Approach 1:
The invention changes the parameter of piston-cylinder head contact by introducing a non-contact region in the second region. This parameter change modifies the load transmission path, distributing tensile loads more evenly across all head bolts rather than concentrating them at boundary regions, thereby reducing the required rigidity and size of the cylinder head while maintaining adequate load bearing capacity.
Data Source
AI summary
When a fluid pressure cylinder (1) is in a maximum expansion state, a piston (40) contacts a cylinder head (30). The cylinder head (30) is fixed to a cylinder tube (10) by a plurality of head bolts (12). The cylinder head (30) includes a pipe attachment seat (36), and the head bolts (12) are disposed in a first region (A) that avoids the pipe attachment seat (36). A non-contact portion in which contact is avoided between the piston (40) and the cylinder head (30) is formed in a second region (B) other than the first region (A), and therefore, when the fluid pressure cylinder (1) is in the maximum expansion state, a tensile load acting on the head bolts (12) on either side of the first region (A) can be suppressed to become equal to a tensile load acting on the other head bolts (12).