Abstract: A fastener system with a coaxial annular flange (14) having through holes (16), each serving to pass a screw (17) for screwing into an associated tapped hole (16) in the wall (2) of a stationary structure. Each through hole (16) has a circularly cylindrical distal segment (16a) followed by an enlarged proximal segment (16b) adjacent to the wall (2) of the stationary structure, allowing the shank (19) of the screw to bend and enabling a corresponding lateral offset (D). This prevents the screw (17) rupturing under high shear forces due to accidental destruction of a vacuum pump rotor while rotating at full speed.

Abstract: The fastener system of the invention comprises a coaxial annular flange (14) having through holes (16) provided therein, each serving to pass a screw (17) for screwing into an associated tapped hole (16) in the wall (2) of a stationary structure. Each through hole (16) comprises a circularly cylindrical distal segment (16a) followed by an enlarged proximal segment (16b) adjacent to the wall (2) of the stationary structure, and allowing the shank (19) of the screw to bend and enabling a corresponding lateral offset (D). This prevents the screw (17) rupturing under high shear forces due to accidental destruction of a vacuum pump rotor while rotating at full speed.

Abstract: There is provided a rotor for a turbo/drag vacuum pump, the rotor comprising an upstream rotor segment of the turbine type made of metal or alloy, and a downstream rotor segment of Holweck type made of composite material. The downstream segment of the rotor has a reinforcing structure made of long fibers that are distributed in a manner that varies as a function of the section under consideration: in the annular connection region connected to the upstream segment of the rotor, the fibers are inclined and/or spaced apart in order to conserve sufficient flexibility for the composite material to enable it to deform so as to track deformation of the metal of the upstream rotor segment while it is in operation; in contrast, the fibers are close together and form turns that touch in the downstream region of the skirt, thereby guaranteeing greater stiffness in order to withstand the mechanical stresses that occur during high-speed rotation of the rotor in operation.

Abstract: The invention concerns a contact roller bearing for a vacuum pump comprising a rotor roller bearing ring (12) a coaxial stator roller bearing ring (13) between which are provided rolling elements (14a, 14b, 14c, 14d) housed in succession and urged to roll on respective raceways of the rotor (12) and stator (13) roller bearing rings. The rolling elements comprise an alternating succession of rolling elements (14a, 14c) whereof the outer surface is made of steel and of rolling elements (14b, 14d) whereof the outer surface is made of ceramic, thereby reducing the resistance to acceleration of the contact roller bearing, which limits the friction and wear of the inner annular surface (16) of the contact roller and the corresponding bearing of the rotor.

Abstract: The invention provides a rotor for a turbo/drag vacuum pump, the rotor comprising an upstream rotor segment of the turbine type made of metal or alloy, and a downstream rotor segment of Holweck type made of composite material. The downstream segment of the rotor has a reinforcing structure made of long fibers that are distributed in a manner that varies as a function of the section under consideration: in the annular connection region connected to the upstream segment of the rotor, the fibers are inclined and/or spaced apart in order to conserve sufficient flexibility for the composite material to enable it to deform so as to track deformation of the metal of the upstream rotor segment while it is in operation; in contrast, the fibers are close together and form turns that touch in the downstream region of the skirt, thereby guaranteeing greater stiffness in order to withstand the mechanical stresses that occur during high-speed rotation of the rotor in operation.

Abstract: According to the invention, a landing bearing for a vacuum pump comprises a rotor ball race and a coaxial stator ball race with rolling elements placed between them, housed one after another and rolling on respective rolling tracks of the rotor and stator ball races. The rolling elements comprise a succession of rolling elements having outside surfaces made of zirconium dioxide. This reduces the resistance of the landing bearing to acceleration, while nevertheless providing good resistance to chemical attacks from process gases and plasmas.

Abstract: In a vacuum pump according to the invention, the rotor is held inside the stator by radial magnetic bearings, and its radial movements are limited by one or more landing mechanical bearings each made up of a rotor rolling bearing race and a stator rolling bearing race. At least one coaxial ring of elastomer in the shape of a torus is inserted between the outside peripheral surface of the stator rolling bearing race and the stator itself to constitute a damped elastic connection which significantly increases the reliability and the service life of the landing mechanical bearing.

Abstract: The invention concerns a contact roller bearing for a vacuum pump comprising a rotor roller bearing ring (12) a coaxial stator roller bearing ring (13) between which are provided rolling elements (14a, 14b, 14c, 14d) housed in succession and urged to roll on respective raceways of the rotor (12) and stator (13) roller bearing rings. The rolling elements comprise an alternating succession of rolling elements (14a, 14c) whereof the outer surface is made of steel and of rolling elements (14b, 14d) whereof the outer surface is made of ceramic, thereby reducing the resistance to acceleration of the contact roller bearing, which limits the friction and wear of the inner annular surface (16) of the contact roller and the corresponding bearing of the rotor.

Abstract: In a vacuum pump according to the invention, the rotor is held inside the stator by radial magnetic bearings, and its radial movements are limited by one or more landing mechanical bearings each made up of a rotor rolling bearing race and a stator rolling bearing race. At least one coaxial ring of elastomer in the shape of a torus is inserted between the outside peripheral surface of the stator rolling bearing race and the stator itself to constitute a damped elastic connection which significantly increases the reliability and the service life of the landing mechanical bearing.

Abstract: A molecular drag pump comprising a rotor housed inside a case having a suction inlet and a delivery outlet, said pump being associated at its inlet with a valve comprising a valve mechanism inside a valve envelope, wherein the valve envelope is integral with said pump case.