Abstract: A damper is configured for a vacuum pump that evacuates a vacuum system via gas transfer by a gas transfer mechanism in the vacuum pump by the rotating action of a rotating body in the vacuum pump. The damper restrains the propagation of vibrations produced in the vacuum pump to the vacuum system during an evacuation operation. The damper comprises a vibration absorbing device that is positionable between the vacuum pump and the vacuum system during an evacuation operation and that has a damping characteristic in a frequency band that coincides substantially with a rotation frequency of the rotating body of the vacuum pump.

Abstract: A stator vane for a turbo molecular pump has stator vane halves each having inner and outer rim portions and radially arranged stator blades connected integrally between the inner and outer rim portions. The inner rim portion of each stator vane half has a pair of inner rim ends and the outer rim portion of each stator vane half has a pair of outer rim ends. The stator vane halves are disposed in abutment with one another along an abutment line to form an annular body with the inner rim ends of one of the stator vane halves being disposed in confronting relation with the respective inner rim ends of the other of the stator vane halves and with the outer rim ends of the one of the stator vane halves being disposed in confronting relation with the respective outer rim ends of the other of the stator vane halves.

Abstract: A magnetic bearing device has a rotor, electromagnets that control axial/radial positions of the rotor, and a power source that supplies power to the electromagnets. A switching circuit switches a voltage of a common node connected to each one end of the electromagnets. The switching circuit includes a first switch element that connects and disconnects between one end of the power source and the common node, and a first rectifier element connected between the other end of the power source and the common node. An excitation control circuit controls excitation of each of the electromagnets by a supply current that flows through the electromagnets in one direction or a regenerated current that flows through the electromagnets in one direction.

Abstract: A vacuum pump evacuates gas from a chamber by coaction of a rotationally driven rotor and a stator. An electrical equipment section that rotates the rotor is housed within a stator column integral with the stator. A cooling water pipe is buried in a wall of the stator column near the electrical equipment section. One end of the cooling water pipe branches into a plurality of water inlet ports and the other end branches into a plurality of water outlet ports. One pair of water inlet and outlet ports opens to the outside of the vacuum pump at a side surface of the stator column and another pair of water inlet and outlet ports opens to the outside at the underside of the stator column.

Abstract: A vacuum pump is provided in which gas molecules in a vacuum chamber are sucked and exhausted by the rotational motion of a rotor rotatably supported in a pump case. At least one nickel alloy layer is disposed on a surface of at least one component defining a flow path in the vacuum pump for increasing a resistance of the component to corrosion due to a corrosive effect of a gas flowing through the flowpath. A nickel oxide is formed on a surface of the nickel alloy layer and has a higher emissivity than that of the nickel alloy layer for increasing a quantity of heat radiated from the surface of the component when the component is heated during operation of the vacuum pump.

Abstract: To improve the assembling efficiency of a urbo-molecular pump having a structure in which the outside diameter of a rotor blade on the exhaust port side is smaller than the outside diameter of a rotor blade on the intake port side. Spacer rings 31f to 31h are set to a threadedly grooved spacer 3. Next, a moving section is inserted along the inner wall of a beanng section of a base 24 from the upside and is fixed. Thereafter, the spacer ring 31f to 31h are raised to provide a clearance between the spacer ring 31h and the threadedly grooved spacer 3. A halved stator blade 30 is inserted between rotor blades 9 via this clearance. After insertion, the spacer ring 31h is lowered, and the stator blade 30 is held by the threadedly grooved spacer 3 and the spacer ring 31h and is fixed. In the same way, the stator blade 30 is inserted between the rotor blades 9 via a clearance between the spacer ring 31h and the spacer ring 31g and a clearanoe between the spacer ring 31g and the spacer ring 31f.

Abstract: To provide a damper capable of reducing vibrations in a particular frequency band while holding the degree of freedom of installation posture of a vacuum pump. A bellows 44 and an elastic member 45 are arranged with a clearance sufficient enough to prevent contact being provided. The elastic member 45 is provided with a spring element K and a damping element C, and the bellows 44 is provided with a spring element k and a mass element m. Thus, a notch filter type vibration isolator is formed. The bellows 44 and the elastic member 45 are set at constants of the elements such that the center frequency (fc) of a notch band is close to the rotation frequency of a rotor 8. The material and expansion amount of member are adjusted so as to agree with the constants of the elements.

Abstract: To provide a magnetic bearing device capable of reducing vibration by preventing a deterioration in the control of a rotor shaft due to a variation in the axial position of the rotor shaft, while performing positional control over the rotor shaft in a specific attitude with optimal magnetic force, and to a turbo molecular pump with the magnetic bearing device mounted thereto. A sensitivity storage section 281 stores therein a sensor sensitivity used in a sensor sensitivity adjustment. The sensitivity storage section 281 outputs the stored sensor sensitivity to a sensitivity switching section. The sensitivity switching section switches the sensor sensitivity according to the situation, and outputs the result to a sensor signal amplifier section.

Abstract: A motor control system has a rotary member, a motor for imparting a torque to the rotary member, a motor driving circuit for supplying power to the motor, and a drive control circuit for controlling a motor current supplied to the motor. An upper limit value of the motor current supplied to the motor is set so as to be variable. At the start of the motor, the drive control means controls the motor current by using the upper limit value as a set value.

Abstract: Provided are a fixing structure for fixing a rotor to a rotor shaft, in which the contact state of the contact surfaces of the rotor shaft and the rotor is stabilized to thereby maintain the rotation balance of the rotor shaft and the rotor, making it possible to prevent oscillation, and a turbo molecular pump having such a fixing structure. On the outer peripheral portion of the upper surface of a fastening portion (253), there is concentrically formed a rotor shaft (213) side contact surface (257) to be brought into contact with a rotor (103). Further, in the inner periphery of the contact surface (257), there is formed a spot facing portion (259) whose upper surface is recessed from the contact surface (257).

Abstract: To provide a magnetic bearing device capable of lowering the costs required for the manufacture, installation, or the like of a turbo molecular pump by reducing the number of elements of an amplifier circuit that drives, through excitation, electromagnets as well as the number of wires of a cable that connects the each electromagnet and the amplifier circuit to each other, and a turbo molecular pump with the magnetic bearing device mounted thereto. One end of an electromagnet coil is connected to a common node. Also, the other end thereof is connected to an amplifier circuit composed of one transistor and one diode. Further, the one end of the electromagnet coil is common with respect to each of the electromagnets, and the common node R is controlled by an intermediate-voltage maintaining circuit so as to maintain an intermediate voltage.

Abstract: A magnetic bearing device is provided which is capable of reducing vibration, as well as electric and magnetic noise, generated from a pump device while making it possible to control the position of a rotor at high speed and high power. Also provided is a pump device having the magnetic bearing device mounted thereto. Switching is made between a high-voltage mode in which an electromagnet coil is supplied with electric power from a high voltage power source and a low voltage mode in which the electromagnet coil is supplied with electric power from a low voltage power source. The switching is made based on whether or not a current change speed is below a reference current change speed. When the current change speed is equal to or larger than the reference current change speed, the device is switched to the high voltage mode. When the current change speed is less than the reference current change speed, the device is switched to the low voltage mode.

Abstract: To reduce vibration caused by an unbalance of magnetic force generated in a motor portion due to run-out of a rotor in a magnetic bearing apparatus having the motor portion. The vibration of the rotor is detected by means of a radial direction sensor mounted for controlling a magnetic bearing. Then, the vibration in the motor portion is inferred from the run-out of the rotor detected by the radial direction sensor by using the geometric positional relationship between the rotor and the radial direction sensor. The relationship between the unbalance amount of the magnetic force and the amount of run-out of the rotor in the motor portion is formed into the database through experiments or simulation in advance, and the unbalance amount of magnetic force is obtained from this database. Then, the magnetic force resisting the unbalance amount of this magnetic force is generated to offset this unbalance amount.

Abstract: To provide a control circuit or the like of a brush-less motor capable of properly controlling current of motor windings by detecting positions of magnetic poles of a rotor at a rotational frequency of the rotor from low rotation which cannot lock a PLL circuit to steady-state rotation for rotating at high speed. Positions of magnetic poles are detected by a change in a magnetic flux (magnetic flux signal) of motor windings caused by rotating a rotor having the magnetic poles, thereby, a synchronizing signal (ROT signal) in synchronism with rotation of the rotor is generated.

Abstract: A vacuum pump has a casing having an interior space, an inlet port for introducing gas molecules into the interior space, and an outlet port for discharging the gas molecules from the interior space. A rotor shaft extends into the interior space of the casing for undergoing rotation about a rotational axis. A stator is connected to the casing and has stator blades extending into the interior space of the casing. A rotor is disposed between the casing and the rotor shaft. The rotor has a preselected number of rotor blades disposed at an uppermost stage thereof and alternately disposed between the stator blades for undergoing rotation with the rotor shaft to direct gas molecules toward the outlet port. A rotational member is disposed between the inlet port and the rotor for undergoing rotation with the rotor shaft about the rotational axis. The rotational member has a generally conical-shaped surface gradually decreasing toward the inlet port.

Abstract: Disclosed are a magnetic bearing device with a vibration restraining function, a magnetic bearing device with a vibration estimating function, and a pump device with the magnetic bearing devices mounted thereto, in which it is possible to realize a reduction in vibration in the apparatus system as a whole inclusive of the equipment associated with the vacuum pump without newly providing a vibration sensor. In a vibration detector, a multiplication result obtained by multiplying the Laplace transformation of a displacement of a rotor by a predetermined transfer function is added to a multiplication result obtained by multiplying the Laplace transformation of a variation in an unbalance force acting on the rotor by the reciprocal of the mass of the rotor. The result of this calculation is reversed in polarity and is added to the output of a compensator by an adder.