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.

A liquid metal or spiral groove bearing structure for an x-ray tube and associated process for manufacturing the bearing structure is provided in which journal bearing sleeve is formed with a number of structures thereon that function to dissipate heat transmitted to the sleeve during operation of the bearing assembly within the x-ray tube to minimize thermal deformation of the sleeve, thereby minimizing gap size alteration within the bearing assembly. The structures formed within the sleeve are slots disposed within the section of the sleeve in which the highest temperature gradients develop. The slots enable an increase in thermal conductance away from the sleeve while minimizing the stresses created from the deformation of the portion(s) of the sleeve between the slots.

A structure and method of operation of a journal bearing is disclosed that minimizes contact of the shaft with the sleeve during start up and slow down of rotation of the shaft relative to the sleeve, or vice versa. The bearing assembly includes a gravitational load reduction mechanism with magnets disposed on the sleeve and on the shaft in alignment with one another. The magnet(s) on the shaft interacts with the magnet(s) disposed on the sleeve to provide a force against the pressure of the shaft towards the sleeve generated by gravity on the rotating component. The magnets enable centering of the rotating component within the stationary component during low rotation and non-rotation. This prevents rubbing of the rotating journal bearing component surfaces, e.g., sleeve, against the stationary journal bearing component, e.g., shaft, during assembly, ramp-up, and coast-down when the journal bearing fluid provides minimal or no bearing centering capability.

A liquid metal or spiral groove bearing structure for an x-ray tube and associated process for manufacturing the bearing structure is provided in which journal bearing sleeve is formed with a number of structures thereon that function to dissipate heat transmitted to the sleeve during operation of the bearing assembly within the x-ray tube to minimize thermal deformation of the sleeve, thereby minimizing gap size alteration within the bearing assembly. The structures formed within the sleeve are slots disposed within the section of the sleeve in which the highest temperature gradients develop. The slots enable an increase in thermal conductance away from the sleeve while minimizing the stresses created from the deformation of the portion(s) of the sleeve between the slots.

Methods and apparatus for predicting x-ray tube liquid bearing failure are disclosed. An example circuit board device includes a sensor to detect, in a free run mode of an x-ray tube, vibration in an x-ray tube housing. The example device includes a digital signal processor to process vibration information representing vibration detected to generate x-ray tube characterization information. The example device includes a communication interface to relay the x-ray tube characterization information to a cloud infrastructure to process the characterization information to generate a failure prediction based on x-ray tube bearing coast down characteristics extracted from the characterization information. Other example instructions cause a machine to receive x-ray tube characterization information related to bearing vibration in the x-ray tube. The instructions, when executed, cause the machine to process the information based on coast down characteristics extracted from the information to identify a rate of failure and/or a time to failure, etc.

An x-ray tube includes a housing containing cooling oil and a vacuum envelope disposed within the housing and including a solid envelope wall. The oil is disposed between the housing and wall. An anode and cathode are arranged in a vacuum environment and surrounded by the wall. A rotor connected to the anode is arranged on bearings within the vacuum environment. Additionally, a stator assembly positioned within the oil surrounds the rotor to define an oil-filled annular gap. The stator assembly includes a stator core, stator teeth spaced apart by intervening stator slots, and stator windings disposed within the stator slots. Each stator tooth includes a tooth tip positioned adjacent to the boundary wall and set a distance apart from the stator windings to form an intra-slot cooling channel in fluid communication with the oil-filled annular gap such that the stator teeth inclusive of its tooth tips are immersed in oil.

Methods and systems for realizing a high speed, rotating anode based x-ray illumination source suitable for high throughput x-ray metrology are presented herein. A high speed rotating anode includes a water cooled rotating platen supported by radial and thrust air bearings employing cascaded differential pumping. A very high bending stiffness of the rotating assembly is achieved by spacing radial air bearings far apart and locating a rotary motor and thrust bearings between the radial air bearings. The high bending stiffness increases the mechanical stability of the rotating assembly during high speed operation, and thus decreases vibration at the location of impingement of the electron beam on the rotating anode material. In some embodiments, magnetic thrust bearings are employed and the air gap is controlled to maintain a desired gap over an operational range of up to three millimeters.

Methods and systems for realizing a high speed, rotating anode based x-ray illumination source suitable for high throughput x-ray metrology are presented herein. A high speed rotating anode includes a water cooled rotating platen supported by radial and thrust air bearings employing cascaded differential pumping. A very high bending stiffness of the rotating assembly is achieved by spacing radial air bearings far apart and locating a rotary motor and thrust bearings between the radial air bearings. The high bending stiffness increases the mechanical stability of the rotating assembly during high speed operation, and thus decreases vibration at the location of impingement of the electron beam on the rotating anode material. In some embodiments, magnetic thrust bearings are employed and the air gap is controlled to maintain a desired gap over an operational range of up to three millimeters.

An X-ray tube is provided. The X-ray tube includes a bearing configured to couple to an anode. The bearing includes a stationary member, a rotary member configured to rotate with respect to the stationary member during operation of the X-ray tube, and a support feature configured to minimize bending moment along a surface of the stationary member to reduce deflection of the stationary member relative to the rotary member due to radial loads during operation of the X-ray tube.

A liquid metal or spiral groove bearing structure for an x-ray tube and associated process for manufacturing the bearing structure is provided that includes a bearing shaft rotatably disposed in a bearing housing or shell. The shell includes a thrust seal engaged with a sleeve to maintain co-axiality for the rotating liquid metal seal formed in the shell about the shaft. The shaft has a bore for the introduction of a cooling fluid into the bearing assembly in which is disposed a cooling tube. The cooling tube includes turbulence-inducing features to increase the turbulence of the cooling fluid flowing through the cooling tube, consequently enhancing the heat exchange between the cooling fluid and the shaft. This maximizes the heat transfer from the shaft to the oil, allowing materials with lower thermal conductivities, such as non-refractory materials, to be used to form the bearing shaft and shell.