A vacuum system includes a vacuum pump and an electric motor for driving the vacuum pump. A cooling arrangement cools the vacuum system. A control performs at least one of decreasing voltage and increasing frequency of a signal applied to the electric motor to decrease an amount of magnetic flux generated in the electric motor instead of decreasing the current applied to the electric motor to arrive at a desired torque generated by the electric motor in response to pumping requirements of the vacuum pump.

In a vacuum pump, a spiral plate on a downstream side of a slit is not disposed on an extended line of a spiral plate on an upstream side of the slit but is disposed after in a direction in which a gap formed by the slit is reduced. The distance by which the downstream spiral plate is moved corresponds to the distance in which the gap disappears and the upstream spiral plate and the downstream spiral plate overlap. When scraping the spiral plates, the radius of a machining end mill is set smaller than the width of the slit of the spiral plate, and the radius of the machining end mill is set smaller than the phase difference between the upstream spiral plate and the downstream spiral plate. In addition, end portions of the spiral plates between which the slit is formed are subjected to chamfering.

The present invention provides a stator component of a vacuum pump, which is suitable for reducing the fracture energy (energy of fracture that occurs when a rotor of the pump is damaged during its rotation) and the size of the pump, and also provides a vacuum pump having this stator component. In the vacuum pump, a spacer or of a thread groove pump stator, which is a stator component forms a gap satisfying the following <<condition>> between an outer circumferential surface of each of housed in a pump case of the vacuum pump, and an inner circumferential surface of the pump case, with the stator component being housed in the pump case. <<Condition>> 2d/D.sub.max, where D is the outer diameter of the stator component (spacer or thread groove pump stator), d is the width of the gap, and .sub.max is the breaking elongation of the stator component.

A fan assembly for a robot vacuum cleaner and a robot vacuum cleaner are provided. The fan assembly includes an electric motor, a stator impeller, a rotor impeller and a fan cover. The stator impeller defines a shaft hole, the electric motor is mounted on a side of the stator impeller, and an output shaft of the electric motor passes through the shaft hole. The fan cover is mounted on another side of the stator impeller, and an end surface of the fan cover away from the stator impeller defines an air inlet. The rotor impeller is mounted to the output shaft of the electric motor and located between the fan cover and the stator impeller.

Provided is a vacuum pump having a stator disc having a divided structure, in which gaps or misalignments that occur between connection surfaces at which the divided structure is connected are reduced. In a turbo-molecular pump according to this embodiment, a mating relationship between a stator disc and a stator member for alignment (center-alignment) is opposite from that of the related art. Specifically, in a structure in which a base and the stator disc are fitted together, center alignment (positioning/centering) is performed through a structure in which an outer peripheral surface of the stator disc is held (restrained from an outer side) by an inner peripheral surface of the base to be connected thereto. Further, the mating structure of the stator disc includes an integral component. Moreover, the mating position of a stator blade and the mating position of the stator disc having a Siegbahn structure are provided separately.

A vacuum pump system comprising a main vacuum pump that is connected to a chamber that is to be evacuated. An auxiliary pump is connected to an outlet of the main vacuum pump. Furthermore, a sealing gas supply device is connected to the main vacuum pump. The sealing gas supply device is switched on and off with the aid of a control device as a function of a predetermined control variable. Additionally, a method for controlling the vacuum pump system.

A drag pump for pumping fluid from an inlet to an outlet includes a stator and a rotor. One of the stator or rotor includes a disc having a plurality of channels each of the channels extending from an inlet portion of the disc at or close to an inlet edge towards an outlet portion at or close to an outlet edge. The plurality of channels each has walls for guiding fluid flow from the inlet edge to the outlet edge in response to relative motion between the stator and the rotor. The disc further includes a plurality of protrusions extending from the channels, each of the protrusions being arranged to divide a channel at the inlet or the outlet end of the channel, into sub-channels that extend for a portion of a length of the channel and do not extend for a whole length of the channel.

A fan motor is disclosed. The fan motor includes an impeller, a rotational shaft, a plurality of bearings, and a heat dissipation fin. The impeller is mounted on the rotational shaft. The plurality of bearings support the rotational shaft. The heat dissipation fin is mounted on the rotational shaft and includes rotating blades rotating centering on the rotational shaft. According to this, the heat dissipation fin may cool the bearing by using convection.

A built-in electric air pump for an inflating object includes a pump casing, a switch hand-wheel, a connection pipe, an air passage switching device, an air pump, and an air valve and a power switch. The pump casing includes a box-shaped chamber. The switch hand-wheel is provided at an external lateral side of the panel. The air passage switching device is provided with an internal pipe having a first opening and a second opening respectively arranged at an upper end and a lower end of the internal pipe. The first opening communicates with outside of the inflating object, and the second opening communicates with the air valve. A diaphragm is provided inside the internal pipe. A first venting hole and a second venting hole are respectively provided on internal walls at two sections of the internal pipe above and below the diaphragm. An external sleeve is provided outside the internal pipe. The lower end of the external sleeve is fixedly connected to the pump casing. The lower end of the external sleeve correspondingly communicates with the air valve. A wall of the external sleeve is provided with an air outlet communicating with an air inlet of the air pump and an air inlet communicating with an air outlet of the air pump. An upper end of the connection pipe is connected to and communicated with the switch hand-wheel, and the lower end of the connection pipe is muff-coupled with the upper end of the internal pipe. The diaphragm of the internal pipe contacts a valve rod of the air valve such that the valve is opened by an applied external force and the diaphragm and the value are moved together.

A gas estimation device for estimating a flow rate and a gas type of gas to be vacuum-pumped by a vacuum pumping device including a vacuum pump and an automatic pressure control valve connected to a suction port of the vacuum pump, comprises: a correlation data storage section configured to store first correlation data containing correlation data regarding an opening degree control gain value of the automatic pressure control valve and correlation data regarding an effective exhaust velocity of the vacuum pumping device and second correlation data indicating a correlation among a flow rate, a gas type, and a motor current value in the vacuum pump; and a first estimation section configured to estimate the flow rate and the gas type of the gas to be vacuum-pumped by the vacuum pumping device based on at least the first correlation data and the second correlation data.