Hydraulic Actuator Sleeve Locking for High Pressure Durability
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Solution Overview
Problem
Conventional McKibben type hydraulic actuators face durability issues when high pressure is applied, particularly with oil pressure driving, leading to potential damage and leakage due to stress concentration and dislodgment of the sleeve from the sealing member.
Innovation Solution
A hydraulic actuator design featuring a cylindrical tube and a braided sleeve with a sealing mechanism that includes a sealing member, a caulking member, and locking rings to secure the sleeve, along with a coating layer on the cord to enhance durability, which prevents the sleeve from being pulled off and reduces friction-related damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If oil pressure driving is adopted to obtain high contraction force, then the contraction force is improved, but the durability deteriorates due to stress concentration and potential damage to the tube and sleeve
Solution Approach 1:
The patent applies preliminary action by pre-caulking the tube end before inserting it into the sealing member body portion. This preliminary caulked structure prevents stress concentration at the tube end during high pressure operation, thereby improving durability while maintaining the ability to withstand high contraction forces from oil pressure driving
Solution Approach 2:
The patent implements beforehand cushioning by creating a folded portion of the sleeve that is inserted into the body portion of the sealing member. This folded portion acts as a cushioning structure that absorbs and distributes stress during high pressure operation, preventing damage to the tube and sleeve while enabling high contraction force operation
2Force
If high pressure is applied to the hydraulic actuator, then the contraction force is improved, but the sleeve might be dropped off from the sealing member
Solution Approach 1:
The patent applies the nesting principle by inserting the folded portion of the sleeve into the body portion of the sealing member, creating a nested structure. This nesting configuration prevents the sleeve from being dropped off during high pressure operation while maintaining structural integrity and enabling high contraction force generation
3Force
If high pressure is applied to the hydraulic actuator, then the contraction force is improved, but the tube might be damaged due to stress concentration
Solution Approach 1:
The patent applies preliminary action by pre-caulking the tube end before insertion into the sealing member. This preliminary caulked structure distributes stress evenly at the tube end, preventing stress concentration and tube damage during high pressure operation, thereby maintaining tube strength while enabling high contraction force
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 design significantly enhances the durability of the hydraulic actuator under high pressure conditions, preventing leakage and damage to the sleeve and tube, ensuring reliable operation even with oil pressure driving.
Implementation Method 1
a tube (110) having a cylindrical shape which is expanded and contracted by pressure of fluid
Data Source
Figure 1
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AI summary
To provide a hydraulic actuator having sufficient durability in a case in which high pressure is applied such as a case in which oil pressure driving is adopted. The hydraulic actuator includes a sealing mechanism (200). A tube (110) is inserted into a body portion (211) of a sealing member (210). A first locking ring (220) locks a sleeve (120) at an outer side of the body portion (211) in the radial direction DR and at a position adjacent to a flange portion (212) . A caulking member (230) caulks the tube (110), the sleeve (120) located at the outer side of the tube in the radial direction DR, a first folded portion (120a) in conjunction with the sealing member (210).