Blood pump bearing system
First Claim
1. A blood-pump bearing system for rotatably supporting a rotor section that is rotatable with respect to a housing through which blood is pumped, said bearing system comprising:
- a shaft for rotatably supporting said rotor section, said shaft having a circumference defined by a first radius, said shaft terminating at a shaft end, said shaft end comprising a radiused surface defined by a second radius, said second radius being greater than said first radius;
an endstone mounted to said housing having a flat planar surface operable to contact said radiused surface of said shaft end;
a shaft circumferential bearing mounted to said housing and having an aperture therethrough for receiving said circumference of said shaft, said shaft circumferential bearing being operable to support radial loads acting on said shaft, said shaft circumferential bearing comprising a curved inner surface that defines said aperture, said curved inner surface being operable for making near line contact along said circumference of said shaft as said shaft rotates, wherein said shaft circumferential bearing comprises an olive hole ring jewel;
wherein a void is formed between said shaft end and said endstone into which pumped blood that leaks between said circumference of said shaft and said shaft circumferential bearing coagulates;
a plurality of individual magnets disposed on said rotor along a path that defines at least a portion of a helix; and
a stator mounted to said housing.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and apparatus are provided for a blood pump bearing system within a pump housing to support long-term high-speed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the shaft to support high speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.
114 Citations
9 Claims
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1. A blood-pump bearing system for rotatably supporting a rotor section that is rotatable with respect to a housing through which blood is pumped, said bearing system comprising:
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a shaft for rotatably supporting said rotor section, said shaft having a circumference defined by a first radius, said shaft terminating at a shaft end, said shaft end comprising a radiused surface defined by a second radius, said second radius being greater than said first radius; an endstone mounted to said housing having a flat planar surface operable to contact said radiused surface of said shaft end; a shaft circumferential bearing mounted to said housing and having an aperture therethrough for receiving said circumference of said shaft, said shaft circumferential bearing being operable to support radial loads acting on said shaft, said shaft circumferential bearing comprising a curved inner surface that defines said aperture, said curved inner surface being operable for making near line contact along said circumference of said shaft as said shaft rotates, wherein said shaft circumferential bearing comprises an olive hole ring jewel; wherein a void is formed between said shaft end and said endstone into which pumped blood that leaks between said circumference of said shaft and said shaft circumferential bearing coagulates; a plurality of individual magnets disposed on said rotor along a path that defines at least a portion of a helix; and a stator mounted to said housing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification