JPH0460193A - Foreign matter capturing device for dry vacuum pump - Google Patents

Abstract

PURPOSE:To eliminate necessity for a filter anxious about blinding by providing a foreign matter depositing member, having an irregular part on the surface, in an internal peripheral surface of a mating sleeve of a contact type seal in which a rotary shaft is inserted. CONSTITUTION:In a dry vacuum pump of screw type small capacity, male and female rotors are fixed to a rotary shaft 2 and synchronously rotated by a timing gear, in a screw type rotor 1. The rotary shaft 2 is supported by an oil lubricated bearing 10. Lubrication of this bearing 10 is performed such that lubricating oil 14 is fed in through a supply oil hole 2a from an eccentric pump mounted to a lower end part of the rotary shaft 2. Here, in order to prevent the lubricating oil 14 from its leakage into a clean rotor machine, a foreign matter accumulating member 21 is provided in the internal peripheral surface of a sleeve 17 while mounting an oil seal 16 between the sleeve 17 and a housing 18. This foreign matter depositing member 21 is formed by using a material of sponge, porous ceramic, porous member, magnet, etc., and providing irregularity on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for collecting foreign matter in bearing lubricating oil of a dry vacuum pump used in semiconductor manufacturing equipment and the like.

[Conventional technology]

Conventional vacuum pump lubricating oil filters often have an oil filter installed at the final return point of the lubricating oil, or have a magnetic filter or plate filter installed at the bottom of the oil tank.

There are also types of vacuum pumps that are equipped with a separate oil-lubricated pump outside the vacuum pump, but these have a line filter installed on the spout side of the oil pump.

[Problem to be solved by the invention]

The problem with the conventional technology described above is that when the filter becomes clogged, the lubricating oil does not return to the tank, resulting in the oil level dropping, making it impossible to supply oil with the eccentric pump, and causing the bearings, gears, seals, etc. to seize up. .

An object of the present invention is to provide a foreign matter collection device that does not require a filter to be installed directly in an oil supply line, and which does not have to worry about clogging of the filter.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a space for retaining foreign matter on the inner peripheral surface of a mating sleeve of a contact type seal, and a magnet,
Alternatively, a foreign matter accumulating member such as a porous member is provided.

[Effect]

When the lubricating oil containing foreign matter passes through the inside of the rotating shaft by the eccentric pump and passes through the oil supply port provided in the mating sleeve of the contact type seal, it is repelled by the centrifugal force of the rotating shaft against the inner peripheral surface of the sleeve. At this time, the foreign matter adheres to the surface of the space provided on the inner peripheral surface of the sleeve and naturally accumulates. The rougher the surface roughness of the space, the larger the contact area, and the more foreign matter can be firmly deposited. Therefore, it is conceivable to provide a member with unevenness or a porous member in the space of the sleeve. Moreover, these members having uneven portions and porous members have the ability to collect foreign matter, whether magnetic or non-magnetic. In particular, since the casing of a vacuum pump is made of minerals, it is effective in collecting highly hard mineral sand. On the other hand, by providing a magnet in the sleeve space, magnetic wear powder from gears, bearings, etc. can be more firmly collected.

〔Example〕 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of a screw type small capacity dry vacuum pump embodying the present invention. Although only one shaft of the screw-type rotor 1 is shown in the figure, there are two shafts, a male rotor and a female rotor, which are fixed at rotation @2 and are synchronously rotated by a timing gear 3 in a non-contact manner.

In addition, another pinion gear 4 attached to the rotating shaft 2
The power from the moder 5 is increased in speed by the Golgyar 6 and the idler gear 7.

In this way, when the rotor 1 rotates, the gas sucked in from the intake port 8 is compressed and transferred by both rotors, and the pressure is increased to atmospheric pressure and exhausted from the exhaust port 9.

The rotating shaft 2 is supported by oil-lubricated bearings 10.11. The lower bearing 11 is lubricated by immersion, but the upper bearing lO and the gears 3, 4, 6.7 are lubricated by an eccentric pump 12 installed at the lower end of the rotating shaft 2, which is provided inside the rotating shaft. This is done by feeding the lubricating oil 14 in the oil tank 13 through the oil supply hole 2a. In order to prevent this lubricating oil 14 from leaking into the clean rotor interior 15, an oil seal 16 is installed between the sleeve 17 and the housing 18. A dry vacuum pump configured in this way requires no space for the installation of a lubricating oil filter.

There may be problems with the performance of the eccentric pump, or if a filter is installed in the oil tank, the filter may become clogged, resulting in poor lubrication of bearings, gears, seals, etc.

An embodiment of the present invention will be described below with reference to FIG. This figure shows the oil seal 16 in Fig. 5. Sleeve 17. This is an enlarged view of the vicinity of the oil supply hole 2a.

When the rotating shaft 2 rotates, the lubricating oil 14 in the oil tank flows from the eccentric pump 12 through the oil supply hole 2a provided inside the rotating shaft.
is coming up. This lubricating oil 14 is applied to the through hole 19 of the rotating shaft 2.
When the oil passes through, it is supplied to three locations: a space 17a provided on the inner peripheral side of the bearing 10° oil seal 16 and sleeve 17. At this time, since the through holes 20 of the sleeve 17 are provided at only two places on the circumference, a considerable amount of oil enters the space 17a on the inner peripheral surface of the sleeve. The oil that has entered is repelled by the centrifugal force of the rotating shaft 2 against the foreign matter accumulating member 21 provided on the inner peripheral surface of the sleeve. At this time, only foreign matter adheres and accumulates on the deposition member 21.

The foreign matter deposition member 21 may be a porous member such as a sponge, a porous ceramic, or a fiber, or a deposition member such as a magnet in order to more firmly adhere the metal powder. In addition, considering that the area for foreign matter to be deposited can be increased, and the foreign matter that has adhered to the depositing member will be difficult to escape, the deposition member 2
Providing irregularities on the surface of 1 or making the surface rougher will further increase the effect of foreign matter collection.

〔Effect of the invention〕

According to the present invention, the problem of filter clogging and securing space can be solved, and a stable supply of oil to bearings, gears, seals, etc. can be achieved, so a shaft seal that does not allow oil mist to enter can be secured, and a clean A dry vacuum pump can be supplied.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a foreign matter collecting portion showing an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of a screw type dry vacuum pump embodying the present invention. 2...Rotating shaft, 2a...Oil supply hole, 16...Oil seal, 17.Sleeve, 17a...Space, 21.Foreign matter deposit D 7-? Katayu 31 Fox---Umagi 2-1 -11 Foreign object

Claims (1)

[Claims] 1. A screw with a pair of right-handed and left-handed screw rotors, the right and left-handed screw rotors are supported by bearings, and the bearing lubricating oil is prevented from leaking to the right-handed and left-handed screw rotors by a contact seal. In this dry vacuum pump, an eccentric pump is installed at the end of the rotating shaft, and a foreign object is installed on the inner peripheral surface of the mating sleeve of the contact type seal to collect foreign objects when the lubricating oil is supplied to the bearing. What is claimed is: 1. A foreign matter collecting device comprising: a space for holding foreign matter; and a foreign matter accumulating member having an uneven surface.