Oil feed nut for providing a lubricant to a bearing of a vacuum pump comprising a first end and an opposite second end and being configured to be connected to a shaft of the vacuum pump. Further, the oil feed nut comprising an oil feeding element extending between the first end and the second end, wherein the oil feeding element has an increasing diameter towards the second end to create an increasing rotational force acting on the lubricant in order to convey the lubricant towards the second end, and a bearing journal element having a cylindrical surface configured to be received in a back-up bearing of the vacuum pump. Therein, the back-up bearing is arranged in a cartridge of an oil reservoir.

A motor driving device comprises a first arithmetic section calculating a rotational speed and a magnetic pole electrical angle of a motor rotor, a current command setting section setting a d-axis current command and a q-axis current command in a rotating coordinate dq system based on a difference between the rotational speed and a target rotational speed, a driving command generating section generating a sinusoidal wave driving command based on the d-axis current command, the q-axis current command, the rotational speed and the magnetic pole electrical angle and a PWM signal generating section. When the rotational speed has a positive value indicating a positive rotational state, the current command setting section sets the q-axis current command of acceleration driving, and when the rotational speed has a negative value indicating a reverse rotational state, the current command setting section sets the q-axis current command of deceleration driving.

To obtain a vacuum pump which appropriately performs temperature management of a gas flow path and reduces restrictions on a gas flow rate attributable to the temperature management. A cooling tube performs temperature adjustment of a gas flow path. A first temperature sensor is arranged at a position closer to the gas flow path than the cooling tube, a second temperature sensor is arranged at a position closer to the cooling tube than the gas flow path, and a control apparatus controls, based on a sensor signal of the first temperature sensor and a sensor signal of the second temperature sensor, (an on-off valve of) the cooling tube so that a temperature of the gas flow path approaches a predetermined gas flow path target temperature.

A first arithmetic section calculates a current rotation component phase value and a current rotation component amplitude value. A second arithmetic section calculates a displacement rotation component phase value and a displacement rotation component amplitude value. A third arithmetic section calculates a ratio between the amplitude value of the current rotation frequency component and the amplitude value of the displacement rotation frequency component. Feedback control is performed such that the current rotation component phase value is equal to a value obtained by addition of a phase value of 180 degrees to the displacement rotation component phase value and that the amplitude value of the current rotation frequency component is equal to a product of the displacement rotation frequency component and the ratio.

The present invention relates to a vacuum pump, in particular to a turbomolecular pump, having at least one pump stage and having a pressure determination unit for determining a pressure present at a suction side of the vacuum pump, said pump comprising a measurement device, with a measurement tap of the measurement device being provided in the region of the pump stage or downstream of the pump stage.

An electromagnet unit, a magnetic bearing device, and a vacuum pump with which displacement of a rotating body in a radial direction can be detected with precision. An upper electromagnet unit includes: radial electromagnets for supporting a rotor in a radial direction without contact; radial sensors for detecting displacement of the rotor in the radial direction; and a core around which coils are wound. Two radial electromagnets that are adjacent to each other in a circumferential direction of the core are disposed such that adjacent magnetic poles belonging respectively to the two radial electromagnets are homopolar, and a low magnetic flux interference region is formed between the two radial electromagnets. Each of the radial sensors is disposed in the low magnetic flux interference region.

The present invention relates to a turbo-molecular vacuum pump comprising bearings for supporting the drive shaft and/or the rotor in relation to a pump body, wherein a first bearing is coupled to the rotor and disposed on supporting mount at the high vacuum side of the rotor and radial struts extend from the supporting mount and form an integral part of the body; the invention is characterised in that the radial struts comprise a hinge portion that can flex to allow relative movement of the inlet flange with respect to the supporting mount to reduce distortion effects.

A reflection mechanism is disposed above a rotor blade. A chamfered surface of the rotor blade is formed to gradually open wide by 0 to 10 degrees toward the downstream side in the rotational direction, from an imaginary line passing through a rotational direction-side tip end point of a horizontal surface and drawn parallel to a rotating shaft. In the reflection mechanism, inclined plates, inclined at a predetermined angle, are arranged radially in the radial direction from a central disc portion. A particle reflected on the chamfered surface of the rotor blade collides with each inclined plate of the reflection mechanism and is then re-reflected and falls in the downstream direction. Since the particle can securely be reflected toward the reflection mechanism, the particle can be prevented from exiting through an inlet port to flow back toward a chamber.

An electromagnet unit in which influence of a noise on a displacement sensor is suppressed and which can be installed in a space-saving manner and a vacuum pump including the electromagnet unit are provided. An electromagnet unit includes a radial electromagnet which controls a shaft to a predetermined position, a radial sensor which detects a position of the shaft, and a printed board interposed between the radial electromagnet and the radial sensor and on which a wiring pattern for sensor connecting coils of the corresponding two radial sensors to each other and a wiring pattern connecting coils of the corresponding two radial electromagnets to each other are provided. The wiring pattern for sensor and the wiring pattern for electromagnet are disposed so as not to overlap when seen from the axial direction.

A vacuum pump comprises: a base; a rotor shaft rotatably provided at the base; a rotor including rotor blades arranged in multiple stages and a rotor cylindrical portion, and attached to the rotor shaft; stationary blades each arranged between adjacent ones of the rotor blades, the stationary blades and the rotor blades forming a turbo exhaust portion; a stator forming, together with the rotor cylindrical portion, a screw groove exhaust portion; and a hexagon socket head cap screw configured to fix the stator to an upper surface of the base in a guiding path of the screw groove exhaust portion to which gas is guided from the turbo exhaust portion. The hexagon socket head cap screw is a bolt having a smaller height of a head portion than that of a hexagon socket head cap screw according to a provision of a country of use or an international organization.