Abstract
The invention relates to a mechanical bearing containing a first component and a further component, wherein the mechanical bearing is designed such that the first component and the further component are able to execute a bearing movement relative to each other, wherein the first component or the further component contains a cermet or both contain a cermet. The invention further relates to an implantable medical device containing the mechanical bearing, in particular to a blood pump, and also to a use of a cermet for producing a mechanical bearing, and to a use of the mechanical bearing for supporting a component of an implantable medical device.
Claims
1. A mechanical bearing containing a first component and a further component, wherein the mechanical bearing is designed such that the first component and the further component are able to execute a bearing movement relative to each other, wherein the first component or the further component contains a cermet or both contain a cermet.
2. The mechanical bearing according to claim 1, wherein the cermet contains a metal in a proportion of at least 20% by weight relative to the total weight of the cermet.
3. The mechanical bearing according to claim 1, wherein the cermet contains a metal in a metal fraction, wherein the metal fraction is a monotonically increasing function from a position on a straight line which runs through the cermet.
4. The mechanical bearing according to claim 3, wherein the metal fraction has a minimum in a range from 0 to 50% by weight based on the weight of a spatial section of the cermet.
5. The mechanical bearing according to claim 3, wherein the metal fraction has a maximum in a range from 50 to 95% by weight based on the weight of a spatial section of the cermet.
6. An implantable medical device containing the mechanical bearing according to claim 1.
7. A method containing as method steps: a) providing a housing; and b) introducing a movable component into the housing; wherein the housing is made of a biocompatible material, wherein the movable component is mounted movably in the housing by means of the mechanical bearing according to claim 1.
8. An apparatus obtainable by the method according to claim 7.
9. A use of a cermet for producing a mechanical bearing.
10. A use of the mechanical bearing according to claim 1 to support a component of an implantable medical appliance.
Description
[0078] In the drawing:
[0079] FIG. 1 shows a schematic cross-sectional view of a mechanical bearing according to the invention;
[0080] FIG. 2a) shows a schematic cross-sectional view of a further mechanical bearing according to the invention;
[0081] FIG. 2b) shows a schematic cross-sectional view of a further mechanical bearing according to the invention;
[0082] FIG. 3 shows a schematic cross-sectional view of a further mechanical bearing according to the invention;
[0083] FIG. 4 shows a schematic cross-sectional view of an implantable medical device according to the invention;
[0084] FIG. 5 shows a schematic view of a left-ventricular heart assist system with a heart pump according to the invention; and
[0085] FIG. 6 shows a flow chart of a method according to the invention.
[0086] FIG. 1 shows a schematic cross-sectional view of a mechanical bearing 100 according to the invention. The mechanical bearing 100 is a sliding bearing, more precisely a radial bearing. The mechanical bearing 100 contains a first component 101, which is a shaft of an electric motor or an axle, and a further component 102, which is a bearing shell. The mechanical bearing 100 is designed such that the shaft/axle 101 and the bearing shell 102 are able to execute a bearing movement 103 relative to each other, a rotation of the shaft/axle 101. The bearing shell 102 is made of a cermet. The cermet is 30% by weight titanium and 70% by weight Al.sub.2O.sub.3, in each case based on the total weight of the cermet. The cermet is biocompatible.
[0087] FIG. 2a) shows a schematic cross-sectional view of a further mechanical bearing 100 according to the invention. The mechanical bearing 100 is a sliding bearing, more precisely an axial bearing. The mechanical bearing 100 contains a first component 101, which is a shaft of an electric motor or an axle, and a further component 102, which is a bearing shell. The mechanical bearing 100 is designed such that the shaft/axle 101 and the bearing shell 102 are able to execute a bearing movement 103 relative to each other, a rotation of the shaft/axle 101. The bearing shell 102 is made of a cermet. The cermet is 25% by weight palladium and 75% by weight ZrO, in each case based on the total weight of the cermet. The cermet is biocompatible.
[0088] FIG. 2b) shows a schematic cross-sectional view of a further mechanical bearing 100 according to the invention. The mechanical bearing 100 is a sliding bearing, more precisely an axial bearing. The mechanical bearing 100 contains a first component 101, which is a shaft of an electric motor or an axle, and a further component 102, which is a bearing shell. The mechanical bearing 100 is designed such that the shaft/axle 101 and the bearing shell 102 are able to execute a bearing movement 103 relative to each other, a rotation of the shaft/axle 101. During the execution of the bearing movement, a first bearing surface 104 of the shaft 101 rubs against a further bearing surface 105 of the bearing shell 102. The bearing shell 102 is made of a cermet with a spatial gradient of a metal fraction. The metal here is platinum. A ceramic component of the cermet is Al.sub.2O.sub.3. The metal fraction at the further bearing surface is 0% by weight based on the weight of a spatial section of the cermet which contains the further bearing surface 105 and contains no point within the cermet farther than 1 mm from the further bearing surface 105. The metal fraction of the cermet becomes greater with a distance from the further bearing surface 105. A maximum of the metal fraction in the cermet is 90% by weight relative to the weight of a spatial section of the cermet.
[0089] FIG. 3 shows a schematic cross-sectional view of a further mechanical bearing 100 according to the invention. The mechanical bearing 100 is an axial ball bearing. The mechanical bearing 100 contains a first component 101, which is a shaft of an electric motor or an axle, and a further component 102, which is a ball in a bearing shell. The mechanical bearing 100 is designed such that the shaft/axle 101 is able to execute a bearing movement 103 relative to the ball 102 and the bearing shell, a rotation of the shaft 101. The ball 102 and the bearing shell are each made of a cermet. The cermet is 28% by weight titanium and 72% by weight AlN, in each case based on the total weight of the cermet. The cermet is biocompatible.
[0090] FIG. 4 shows a schematic cross-sectional view of an implantable medical device 400 according to the invention, which is a heart pump. Blood, which flows in the direction of blood flow 401 into the heart pump 400, initially passes through a flow straightener 402, which reduces turbulence of the blood flow. A shaft 101 carries an impeller 403. The shaft 101 and thus the impeller 403 are mounted in a sliding bearing 100 according to the invention. The impeller strengthens the flow of the blood and thus assists the pumping function of the heart. The heart pump 400 moreover contains a diffusor 404. The shaft 101 is driven by an electric motor, of which the stator 405 is accommodated in a hermetically sealed manner in a housing 406. The electric motor here drives the shaft 101 without contact, by means of an electromagnetic field. The electric motor is operated with current via a power cable 407.
[0091] FIG. 5 shows a schematic view of a left-ventricular heart assist system 500 with an implanted heart pump 400 according to the invention as per FIG. 4. The heart pump 400 is attached by a blood-conveying tube 503 to the apex of the heart 501 and via a further blood-conveying tube 503 to the aorta 502. A power cable 407, which supplies current to the heart pump 400, runs from inside the body of the patient out through a skin boundary 504 to a control unit 505, which controls the heart pump 400. The control unit 505 can be worn on a belt by the patient. The control unit 505 is connected by further power cables 407 to two batteries 506. The patient can carry each of the batteries 506 in a respective shoulder strap.
[0092] FIG. 6 shows a flow chart of a method 600 according to the invention for producing a heart pump 400. In a method step a) 601, a housing made of titanium and with a flow channel is made available. In a method step b) 602, a shaft/axle 101 with an impeller 402 is introduced into the flow channel. The shaft/axle 101 is mounted in the flow channel with the radial bearing as per FIG. 1.
LIST OF REFERENCE SIGNS
[0093] 100 mechanical bearing according to the invention [0094] 101 first component/shaft/axle [0095] 102 further component [0096] 103 bearing movement [0097] 104 first bearing surface [0098] 105 further bearing surface [0099] 400 implantable medical device according to the invention/heart pump [0100] 401 direction of blood flow [0101] 402 flow straightener [0102] 403 impeller [0103] 404 diffusor [0104] 405 motor stator [0105] 406 housing [0106] 407 power cable [0107] 500 left-ventricular heart assist system [0108] 501 heart [0109] 502 aorta [0110] 503 tube [0111] 504 skin boundary [0112] 505 control unit [0113] 506 battery [0114] 600 method according to the invention [0115] 601 method step a) [0116] 602 method step b)
