Provided is a pump monitoring device for detecting abnormalities of multiple vacuum pumps connected to the same chamber, the pump monitoring device being configured to estimate occurrence of the abnormality at any of the multiple vacuum pumps based on a comparison result of signals indicating rotation states of pump rotors of the multiple vacuum pumps.

A magnetic bearing vacuum pump comprises: a first displacement signal generation section configured to amplify, by a resolution multiplying factor K of K>1, a displacement modulated wave signal modulated according to a displacement of the rotor from a predetermined position to generate a high-resolution displacement signal in a first displacement region including the predetermined position; a second displacement signal generation section configured to generate a low-resolution displacement signal in a larger second displacement region including the first displacement region; a selection section configured to select either one of the high-resolution displacement signal or the low-resolution displacement signal based on an unsteady-state response signal obtained by excluding a steady-state whirling displacement component from the high-resolution displacement signal or the low-resolution displacement signal; and a bearing control section configured to control the magnetic bearing based on the displacement signal selected by the selection section.

A magnetic bearing control device is configured to detect, by a sensor, excitation current supplied from an excitation amplifier to a magnetic bearing configured to magnetically levitate a rotor, thereby generating a voltage equivalent signal for PWM control of the excitation amplifier based on a current setting signal based on a deviation of a rotor levitation position with respect to a target levitation position and an excitation current detection signal of the sensor. The voltage equivalent signal is generated based on the current setting signal and a current deviation signal as a difference between the current setting signal and the excitation current detection signal.

There is obtained a vacuum pump which suppresses an influence on external piping caused by a contact failure of a rotor during rotation of the rotor. A temperature rise ring 301 is provided in the vacuum pump, an outlet port 133 to which the external piping is connected is connected to the temperature rise ring 301, and a rotational force is directly or indirectly applied to the temperature rise ring 301 due to the contact failure of the rotor during the rotation of the rotor. In addition, a rotation suppression means (a hole 301a and a bolt 305) for suppressing rotation of the temperature rise ring 301 by the above-described rotational force is provided separately from a connection portion between the temperature rise ring 301 and a casing (outer tube 127a).

A vacuum pump, vacuum pump arrangement and method are disclosed. The vacuum pump comprises: at least one rotor; and a stator, an inlet for receiving gas during operation; and an exhaust for exhausting the gas. The vacuum pump comprises a shaft extending through a centre of said pump and comprising a plate mounted on an end of the shaft towards the inlet. The vacuum pump comprises control circuitry configured to control an axial position of the plate, a change in axial position of the plate providing a change in inlet conductance of gas to the vacuum pump. The plate is mounted such that it extends beyond the inlet in at least some axial positions of the rotor such that the plate is not on the same side of the inlet as the stator.

In a vacuum pump, a portion of a lower end portion of a rotating cylindrical body is cut in an axial direction thereof to form an imbalance correction portion (removal portion). Preferably, the removal portion is formed so as to minimize an axial width of the rotating cylindrical body and set a circumferential width of the rotating cylindrical body to a value of not less than a thickness (width in a radial direction) of the rotating cylindrical body. Additionally, a corner formed in the removal portion is formed to have a large. With this configuration, in the rotating cylindrical body, the removal portion is formed to have a shape in which a removal width (depth) in the axial direction of the rotating cylindrical body is small and a removal width in the circumferential direction thereof is large.

The present disclosure relates to a rotor assembly 102 for a turbomolecular pump 100. The rotor assembly 102 comprises a rotor shaft 116, a plurality of rotor blades 126 extending from the rotor shaft 116, and a balancing member 130 fitted within the rotor shaft 116 with an interference fit. The rotor shaft 116 extends along a longitudinal axis 122 about which the rotor assembly 102 is configured to rotate. The interference fit is such that the balancing member 130 is retained in compression by the rotor assembly 102. The present disclosure also relates to a turbomolecular pump 100 including the rotor assembly 102 and a method of assembling a rotor assembly 102 for the same.

A vacuum pump which can reduce a stress generated in a connected part between a rotating body and a rotating shaft is provided. A rotating body is provided having rotor blades provided on an outer periphery of a rotor-blade forming portion, and fastened to the rotor shaft by a bolt, and rotatable with the rotor shaft. At least either one of a fitting hole portion fitted with the rotating shaft and a through hole portion, through which a bolt penetrates, in the rotating body is a stress-reduction target portion, and a groove portion that reduces stress generated in the stress-reduction target portion during rotation of the rotating body is provided.

A vacuum pump which can prevent lowering of an exhaust performance of the vacuum pump, even if a linked-type thread groove spacer is fastened by a fixing bolt, is provided. The linked-type thread groove spacer according to an embodiment of the present invention includes a structure for linking a Siegbahn pump portion and a thread-groove pump portion. When this linked-type thread groove spacer is to be fastened, a countersunk hole is provided in advance in an exhaust channel portion, and the linked-type thread groove spacer is fastened to a base by a fixing bolt. As a result, a head part of the fixing bolt does not protrude to the exhaust channel, and the head part of the fixing bolt does not make resistance against an exhaust gas. Thus, lowering of the exhaust performance of the vacuum pump can be suppressed.

A pump bearing holder has a carrier portion configured to carry a static set of magnets of a pump magnetic bearing and a support portion extending outwardly of the carrier portion to connect with a pump casing such that the pump bearing holder spans an inlet provided in the pump housing. The support portion defines a plurality of internal through-passages that, in use, allow a gas flowing through the inlet to flow through the support portion.