Shock Absorber Rod Guide Grooves for Piston Rod Lubrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hydraulic shock absorbers, the velocity of fluid inside the first cylinder increases near the opening in the cover member, leading to uneven fluid pressure and potential lack of fluid in the gap between the piston rod and the cover member, causing wear and reducing durability.
Innovation Solution
A hydraulic shock absorber design with a cover member featuring a fluid supply unit that includes a flow forming passage to ensure fluid flows into the gap between the inner circumferential surface of the through hole and the outer circumferential surface of the piston rod, preventing a lack of fluid and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an opening is formed in the cover member to allow fluid flow from the first cylinder to the fluid reserving chamber, then fluid circulation is improved, but fluid pressure near the opening decreases causing insufficient fluid supply to the gap between piston rod and cover member
Solution Approach 1:
A fluid supply unit is introduced as an intermediary component between the first cylinder and the gap between the piston rod and cover member. This unit actively supplies fluid to the gap, mediating the fluid flow to ensure adequate lubrication despite the pressure reduction caused by the opening for fluid circulation.
Solution Approach 2:
The cover member is designed with different functional regions: an opening portion for fluid circulation and a through-hole portion for piston rod passage. The fluid supply unit is specifically positioned to address the local fluid pressure issue at the gap location, providing localized fluid supply where needed while maintaining overall fluid circulation through the opening.
2Ease of operation
If the cover member has a through hole for piston rod penetration, then piston rod movement is enabled, but fluid may not adequately supply the gap causing wear of the cover member
Solution Approach 1:
The fluid supply unit acts as an intermediary that ensures adequate fluid supply to the gap between the piston rod and cover member inner circumferential surface, preventing direct metal-to-metal contact and wear while allowing free piston rod movement through the through hole.
Solution Approach 2:
The fluid supply unit proactively supplies fluid to the gap before wear can occur, ensuring continuous lubrication is maintained throughout operation. This preliminary protective action prevents the cover member from wearing down over time.
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 design prevents wear of the cover member, enhancing the durability of the hydraulic shock absorber by maintaining consistent fluid flow and reducing friction.
Implementation Method 1
the fluid supply unit includes a flow forming passage being arranged inside the cover member, wherein one end of the flow forming passage is connected to the gap, and the other end of the flow forming passage opens into the first cylinder
Data Source
Figure 1~2
Figure 3~4-1A
Figure 4-2B~5B
AI summary
The hydraulic shock absorber includes a cylinder containing a fluid, a damper case positioned outside the cylinder to form a reserving chamber, a piston housed inside the cylinder, a piston rod supporting the piston, a rod guide covering one end of the cylinder, and a guide bushing provided with a through hole through which the piston rod penetrates. The rod guide has an outer circumferential groove formed by spacing apart at least a part of the rod guide from the cylinder in a circumferential direction of the cylinder for allowing the fluid to flow from inside of the cylinder to the reserving chamber, and has an inner circumferential groove for supplying the fluid into an inner circumferential gap between an inner circumferential surface of the guide bushing and an outer circumferential surface of the piston rod as the fluid flows through the outer circumferential groove.