Shaft seal structure of vacuum pumps
AssigneeKabushiki Kaisha Toyota Jidoshokki
InventorsShinya Yamamoto, Masahiro Kawaguchi, Satoshi Egashira
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. This enlarges the diameter of each labyrinth seal, thus preferably preventing oil from leaking to a pump chamber.
Claims21
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 has a projecting section that projects from the pump chamber to the oil zone through the oil housing member;
- an annular shaft seal, which is located around the projecting section to rotate integrally with the rotary shaft, wherein the shaft seal has a first seal forming surface that extends in a radial direction of the shaft seal;
- a second seal forming surface, which is directly formed on the oil housing member, wherein the second seal forming surface opposes the first seal forming surface and is substantially parallel with the first seal forming surface;
- and
- a labyrinth seal, which is located between the first and second seal forming surfaces.
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 first seal forming surface perpendicular to the axis of the associated rotary shaft;
- a pair of second seal forming surfaces, which are directly formed on the partition, wherein each second seal forming surface opposes one of the first seal forming surfaces and is substantially parallel with the first seal forming surface;
- and
- a pair of labyrinth seals, each of which is located between one of the first seal forming surfaces and the associated second seal forming surface.
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 has a projecting section that projects from the pump chamber to the oil zone through a through hole formed in the oil housing member;
- an annular shaft seal, which is located around the projecting section to rotate integrally with the rotary shaft, wherein the shaft seal has a first seal forming surface that extends in a radial direction of the shaft seal;
- a second seal forming surface, which is formed on the oil housing member, wherein the second seal forming surface opposes the first seal forming surface and is substantially parallel with the first seal forming surface;
- a labyrinth seal, which is located between the first and second seal forming surfaces;
- and
- a pressure introducing line that introduces the pressure in a maximum pressure zone located in the pump chamber to the labyrinth seal through the through hole, wherein the oil housing member has a wall surface exposed to the maximum pressure zone, and the pressure introducing line is a groove formed in the wall surface.
Dependencies are inferred from the claim text.