According to one embodiment, a sliding bearing unit includes a stationary shaft including a first radial bearing surface, a rotor, and a lubricant. The rotor includes a first cylinder and a second cylinder. The second cylinder includes a second radial bearing surface and is restricted in operation so that it does not rotate relative to the first cylinder. The lubricant, together with the first radial bearing surface and the second radial bearing surface, forms a dynamic pressure radial sliding bearing.

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a sleeve. The structure of sleeve is formed with enlarged traps or voids in the sleeve that are disposed adjacent various rotating anti-wetting seals/seal surfaces formed between the sleeve and the shaft. The geometry of the traps is formed to retain liquid metal/lubricating fluid within the gap defined by the bearing assembly and to direct to liquid metal flowing outwardly from the gap defined between the sleeve and the shaft away from the rotating anti-wetting seals and back towards the gap. This geometry allows the centrifugal forces exerted on the liquid metal by the rotation of the bearing structure to move the outflowing liquid metal away from the rotating anti-wetting seals to significantly reduce contact of the liquid metal with the seals.

A rotary x-ray anode with an integrated liquid metal bearing outer shell has an anode disc made of Mo or a Mo-based alloy formed with a hole, which is formed centrally in the region of the axis of rotation and extends in the axial direction at least through part of the anode disc, and a bearing bushing made of Mo or a Mo-based alloy. The bearing bushing is connected to the anode disc via a material bond and its inner wall extends the hole in the anode disc. At least an axial portion of an inner wall of the hole in the anode disc and at least an axial portion of an inner wall of the bearing bushing are formed circumferentially as a liquid metal bearing running surface and they form at least a part of a liquid metal bearing outer shell. There is also described a corresponding production method.

The rotatable anode of a rotating anode X-ray source has demanding requirements placed upon it. For example, it may rotate at a frequency as high as 200 Hz. X-ray emission is stimulated by applying a large voltage to the cathode, causing electrons to collide with the focal track. The focal spot generated at the electron impact position may have a peak temperature between 2000° C. and 3000° C. The constant rotation of the rotating anode protects the focal track to some extent, however the average temperature of the focal track immediately following a CT acquisition protocol may still be around 1500° C. Therefore, demanding requirements are placed upon the design of the rotating anode. The present application proposes a multi-layer coating for the target region of a rotating X-ray anode which improves mechanical resilience and thermal resilience, whilst reducing the amount of expensive refractory metals required.

Systems and methods related to hydrodynamic bearings for use in X-ray sources are provided. In one aspect, a hydrodynamic bearing system includes a sleeve assembly including a cross-member fluidically dividing a first interior cavity from a second interior cavity, a first shaft positioned in the first interior cavity, and a second shaft positioned in the second interior cavity. The hydrodynamic bearing system may further include a first journal bearing including a first fluid interface surrounding at least a portion of the first cantilever shaft and configured to support radial loads and a second journal bearing including a second fluid interface surrounding at least a portion of the second cantilever shaft and configured to support radial loads.

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a bearing sleeve, one of which rotates relative to the other. The stationary component, e.g., the journal bearing and/or the thrust bearing includes at least one vent groove formed therein that improves the ability of the journal bearing structure to enable gases trapped by the liquid metal within the bearing assembly to escape through the vent groove to the exterior of the X-ray tube. By adding a strategically located channel or vent groove of sufficient size in at least one of the journal bearing or the thrust bearing, the pressures resisted by the seal created between the liquid metal and the vent groove(s) in the bearing components is significantly reduced, allowing escape of the gases to avoid detrimental effects to the operation of the X-ray tube, while maintaining the load carrying capacity of the bearing assembly.

In one embodiment, a rotating anode type X-ray tube comprises a fixed shaft having a first surface, a rotor, a cathode emitting electrons, and an anode target. The rotor comprises a first cylinder having a second surface, a second cylinder, and a third cylinder. A first threaded portion on an inner surface of the first cylinder and a second threaded portion on an outer peripheral surface of the third cylinder are tightened. A screw member is screwed in a third threaded portion on an inner peripheral surface of a hole which penetrates the third cylinder, and a tip portion of the screw member presses the second cylinder against the second surface.

Technology is described for a magnetic lift device for an x-ray tube. In one example, an anode assembly includes an anode, a bearing assembly, a ferromagnetic shaft, and a lift electromagnet. The anode is configured to receive electrons emitted by a cathode. The bearing assembly is configured to stabilize the anode during a rotation of the anode. The ferromagnetic shaft is coupled to the anode and has an axis of rotation that is substantially collinear with an axis of rotation of the anode. The lift electromagnet is configured to apply a magnetic force to the ferromagnetic shaft in a radial direction.

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a sleeve. The structure of sleeve is formed with enlarged traps or voids in the sleeve that are disposed adjacent various rotating anti-wetting seals/seal surfaces formed between the sleeve and the shaft. The geometry of the traps is formed to retain liquid metal/lubricating fluid within the gap defined by the bearing assembly and to direct to liquid metal flowing outwardly from the gap defined between the sleeve and the shaft away from the rotating anti-wetting seals and back towards the gap. This geometry allows the centrifugal forces exerted on the liquid metal by the rotation of the bearing structure to move the outflowing liquid metal away from the rotating anti-wetting seals to significantly reduce contact of the liquid metal with the seals.

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a bearing sleeve, one of which rotates relative to the other. The stationary component, e.g., the journal bearing and/or the thrust bearing includes at least one vent groove formed therein that improves the ability of the journal bearing structure to enable gases trapped by the liquid metal within the bearing assembly to escape through the vent groove to the exterior of the X-ray tube. By adding a strategically located channel or vent groove of sufficient size in at least one of the journal bearing or the thrust bearing, the pressures resisted by the seal created between the liquid metal and the vent groove(s) in the bearing components is significantly reduced, allowing escape of the gases to avoid detrimental effects to the operation of the X-ray tube, while maintaining the load carrying capacity of the bearing assembly.