Bearing Housing Coupling for Drive Cable to Hollow Shaft Bonding
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Solution Overview
Problem
Current ventricular assist devices face challenges in securely coupling drive cables to hollow shafts, which is crucial for maintaining mechanical integrity and efficient operation, especially in the context of ventricular assist devices used for cardiac support.
Innovation Solution
A method involving a drive cable with coiled wires and a hollow shaft, where the drive cable end and hollow shaft end are inserted into a coupling tube, and a molten material, such as polyether ether ketone (PEEK), is flowed between the wires and into the shaft through the coupling tube pores, solidifying to bond the drive cable to the shaft, with additional reinforcement using tabs and a heat-shrinking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a molten material bonding process is used to couple the drive cable to the shaft, then the strength of the coupling is improved, but the device complexity increases
Solution Approach 1:
The patent utilizes phase change of the bonding material from solid to molten state and back to solid to create the coupling. The material is heated to become molten, allowing it to flow into the shaft pores and bond the drive cable, then cooled to solidify and strengthen the coupling. This parameter change enables strong bonding without complex mechanical assembly processes.
Solution Approach 2:
The patent replaces traditional mechanical coupling methods (such as threads, keys, or interference fits) with a thermal bonding process. Instead of using mechanical interlocking structures, the coupling is achieved through molten material that penetrates the shaft pores and solidifies, creating a unified structure that eliminates the need for separate coupling components.
2Reliability
If tabs are pushed into shaft pores for reinforcement, then the reliability of the coupling is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes the porous structure of the shaft, with multiple shaft pores distributed along its length. These pores serve as receptacles for the tabs, allowing them to be securely positioned without requiring high-precision machining of individual pore locations. The porous structure provides natural alignment and retention features that simplify manufacturing while ensuring reliable coupling.
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 solution provides a strong, secure, and continuous lumen coupling, enhancing the mechanical stability and operational efficiency of the drive cable and shaft assembly, critical for the effective functioning of ventricular assist devices.
Implementation Method 1
a molten material is flowed between the coiled wires at the drive-cable end via the coupling-tube pores, and into the hollow-shaft end via the coupling-tube pores and shaft pores, such that, upon solidifying, the material bonds the drive cable to the shaft
Implementation Method 2
the material bonds the drive cable to the shaft
Implementation Method 3
heat is applied to the sleeve of the material and to the outer sleeve. The applied heat melts the sleeve of the material
Implementation Method 4
shrinks the outer sleeve such that the outer sleeve forces the molten material between the coiled wires of the drive cable and into the proximal end of the axial shaft
Data Source
AI summary
Apparatus and methods are described including an axial shaft configured for insertion into, and rotation within, a subject's body. A delivery tube extends to the axial shaft, from outside the subject's body, while the axial shaft is within the subject's body. An impeller is coupled to the axial shaft such that, as the axial shaft rotates, the impeller pumps blood of the subject. Proximal and distal radial bearings surround the axial shaft, proximally and distally to the impeller respectively, the proximal and distal radial bearings being configured to radially stabilize the axial shaft while the axial shaft rotates. A proximal bearing housing houses the proximal radial bearing and is coupled to the delivery tube. A drive cable rotates the axial shaft while extending through the delivery tube, and is coupled to the axial shaft within the proximal bearing housing. Other applications are also described.