Shaft seal structure of vacuum pumps
AssigneeKabushiki Kaisha Toyota Jidoshokki
InventorsNobuaki Hoshino, Mamoru Kuwahara, Masahiko Okada, Shinya Yamamoto
Life of this patent
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Abstract
A Roots pump rotates a plurality of rotors by a pair of rotary shafts to draw gas. Each rotary shaft extends through a rear housing member of the Roots pump. An annular shaft seal is fitted around each rotary shaft and is received in a recess formed in the rear housing member. A labyrinth seal is located between an end surface of each shaft seal and the bottom of the associated recess. A resin layer is firmly attached to the end surface of each shaft seal. As a result, oil is reliably prevented from leaking into a pump chamber.
Claims12
A vacuum pump that draws gas by operating a gas conveying body in a pump chamber through rotation of a rotary shaft, the vacuum pump comprising:
- an oil housing member, wherein the oil housing member forms an oil zone adjacent to the pump chamber, and the rotary shaft extends from the pump chamber to the oil zone through the oil housing member;
- and
- a labyrinth seal, which is located between the rotary shaft and the oil housing member and is formed on the opposite portions of the rotary shaft and the oil housing member and is directly formed on the oil housing member, wherein the labyrinth seal includes a resin layer, which minimizes the space between the rotary shaft and the oil housing member.
A Roots pump, comprising:
- a housing, wherein the housing has a pump chamber and an oil zone, and the housing includes a partition that separates the pump chamber from the oil zone;
- a pair of parallel rotary shafts, wherein each rotary shaft extends from the pump chamber to the oil zone through the partition;
- a pair of rotors, each of which is located in the pump chamber and is formed around one of the rotary shafts, wherein the rotor of one rotary shaft engages with the rotor of the other;
- a gear mechanism, which is located in the oil zone, wherein the gear mechanism connects the rotary shafts to each other such that the rotary shafts rotate integrally;
- a pair of annular shaft seals, each of which is located in the oil zone and is fitted around one of the rotary shafts to rotate integrally with the rotary shaft, wherein each shaft seal has a side that faces the partition;
- a pair of opposite surfaces directly formed on the partition, wherein each opposite surface faces the side of one of the shaft seals;
- and
- a pair of labyrinth seals, each of which is located between the side of one of the shaft seals and the corresponding opposite surface, wherein each labyrinth seal includes a resin layer, which minimizes the space between the corresponding side and the corresponding opposite surface.
Dependencies are inferred from the claim text.