Grooved Spring Sleeve for Low-Wear Piston-Cylinder Guidance
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Solution Overview
Problem
Piston-cylinder units face issues with increased friction and wear due to the expansion and contraction of helical springs, leading to potential jamming, noise, and damage, and existing solutions either increase friction or are costly and difficult to manufacture, while lubricant distribution is inefficient.
Innovation Solution
The use of spring sleeves with axial grooves on their inner surfaces, which act as lubricant reservoirs and reduce friction by minimizing the contact area with the spring, improving lubrication and guiding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring sleeve has a larger tolerance to prevent spring jamming, then the spring can move freely, but the risk of buckling and inelastic deformation increases
Solution Approach 1:
The spring sleeve has different surface properties in different regions: grooves are created at specific locations to provide localized spring support and guidance, while other regions maintain smooth surfaces to minimize friction and allow free spring movement. This local differentiation enables the sleeve to provide necessary guidance without causing buckling.
Solution Approach 2:
The continuous inner surface of the spring sleeve is segmented by creating grooves that divide the surface into distinct regions. These grooves act as separate guidance elements that support the spring at critical points while allowing movement in other areas, preventing both jamming and buckling.
2Reliability
If an elastic outer layer is added to the spring to stabilize it, then the risk of damage to friction partners is reduced, but friction and abrasion between spring and friction partners increases
Solution Approach 1:
Instead of adding an elastic outer layer to the spring, the invention extracts the stabilization function and transfers it to the spring sleeve through grooves. The grooves provide the necessary guidance and support to prevent spring buckling without requiring additional layers on the spring itself, thereby avoiding increased friction and abrasion.
3Object-generated harmful factors
If lubricant is applied between spring and friction partners, then wear and noise are reduced, but lubricant is displaced or accumulates due to stroke movement
Solution Approach 1:
The grooves are pre-formed in the spring sleeve to create lubricant retention channels before the piston-cylinder unit begins operation. When lubricant is applied, it is immediately captured and held in these grooves, preventing displacement during stroke movement and ensuring continuous lubrication throughout operation.
4Object-generated harmful factors
If friction-reducing spacers are added to the guide tube, then direct contact between spring and guide tube is prevented, but lubricant runs off between spacers and accumulates at lower end
Solution Approach 1:
Instead of using discrete spacers that create gaps, the invention uses grooves that extend in the axial dimension along the spring sleeve. This dimensional change allows the grooves to capture and retain lubricant along the entire length of the spring contact area, preventing lubricant from running off to the lower end and ensuring uniform lubrication distribution.
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 grooved design reduces friction and vibration transmission, enhances lubrication by retaining lubricant through surface tension, and extends the service life and maintenance intervals of the piston-cylinder unit, while being cost-effective and easier to manufacture.
Implementation Method 1
the grooves act as a reservoir for a lubricant used in the piston-cylinder unit. In particular, due to surface tension effects of the lubricant, the grooves retain some of the lubricant even as the remainder of the lubricant collects at the other end of the piston-cylinder assembly due to gravity
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a spring sleeve (4, 5) for a piston-cylinder unit (1), wherein the spring sleeve (4, 5) is configured to at least partially receive and guide a spring (3), and wherein the spring sleeve (4, 5) preferably has a cylindrical inner surface. The invention further relates to a cylinder for a piston-cylinder unit (1), wherein the cylinder (2) is configured to be arranged within a spring (3) of a piston-cylinder unit (1). The invention also relates to a piston-cylinder unit (1) comprising a cylinder (2), a spring (3) arranged concentrically around the cylinder (2), an inner spring sleeve (5) and an outer spring sleeve (4) each arranged concentrically around the spring, wherein the cylinder (2) and the spring (3) are arranged within the inner spring sleeve (5) and the outer spring sleeve (4), respectively. Finally, the invention relates to a method for manufacturing such a piston-cylinder unit (1).The object of the invention is to provide a spring sleeve for a piston-cylinder unit, a cylinder for a piston-cylinder unit, a piston-cylinder unit, and a manufacturing method for producing such a piston-cylinder unit, which enable reduced wear and improved movement characteristics of a piston-cylinder unit. According to the invention, this object is achieved by the inner spring sleeve (5) and/or the outer spring sleeve (4) and/or the cylinder (2) having a number of grooves (6) on a surface facing the spring (3).