JPH086701B2 - Vacuum pump oil drainer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oil drainer for preventing oil from entering, and in particular, an oil drainer suitable for an oilless vacuum pump using a non-contact balance type shaft seal. Regarding

[Conventional technology]

In the conventional device, as described in Japanese Patent Laid-Open No. 63-32187, the working chamber and the bearing chamber are communicated with each other by an external pipe in order to balance the pressure. In addition, as another means, the bearing and the oil splashing plate (slinger) or the upper part of the gear chamber is covered with a plate-shaped baffle, and the shaft sealing pressure balancing communication hole (hereinafter referred to as a pressure equalizing hole) provided in the housing is used. By installing a pressure equalizing pipe and arranging the opening of the pressure equalizing pipe above the baffle, it is possible to prevent the splash of oil splashed by the oil splash plate or gear for bearing lubrication from entering the pressure equalizing hole. There are some.

[Problems to be Solved by the Invention] The above-described conventional technique requires external piping, baffle plates, pressure equalizing pipes, and the like, and therefore requires additional manufacturing costs, installation costs, and the like, resulting in high costs. Further, it is necessary to secure a mounting space for them, which is an obstacle to downsizing.

An object of the present invention is to provide an oil removing device which has an extremely simple structure, is inexpensive, and can be realized compactly.

[Means for solving the problem]

The above-described object is to provide a pair of male and female rotors, a lubrication bearing that supports the rotors, a housing that accommodates these, a drive device for the rotor, a working chamber formed by the rotors and the housing, A vacuum pump for balancing the pressure in both chambers by providing a means for communicating the shaft sealing device provided between the bearing chamber accommodating the bearing and the working chamber with the bearing chamber working chamber side. Means for balancing the pressure of the passage, when extending in the counter-rotational direction from an opening provided in the suction side housing cover surface forming the bearing chamber and communicating with the bearing chamber, the passage communicating the groove with the working chamber. It is achieved by being formed from and.

[Action]

The opening to the bearing chamber side of the groove provided on the flange joint surface of the suction side housing cover that forms the bearing chamber is installed at a position and a direction in which the oil does not scatter. Further, since it is connected to the working chamber through the passage (pressure equalizing hole) which is opened at this position and penetrates the housing, it is possible to prevent oil from entering the pressure equalizing hole.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.
It will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a dry screw vacuum pump body which is an embodiment of the present invention, FIG. 2 is a transverse sectional view of the same, and FIG. 3 is a sectional view taken along the line AA of FIG.

Reference numeral 1 is a male screw rotor, and 2 is a female screw rotor, which are rotatably housed in a main housing 7 and a suction side housing 8 by bearings 3, 4, 5 and 6, respectively. The male rotor 1 is driven by a drive device (not shown), and both rotors rotate synchronously by the timing gears 9 and 10 to produce a pump effect. 11 is an intake port and 12 is a discharge port. The discharge side bearings 3 and 5 are forcibly supplied with oil by an oil supply device (not shown). Further, 13 and 14 are non-contact gas purging type discharge side shaft seals to prevent the bearing lubricating oil from entering the working chamber 30 (meshing space formed by both rotors). Reference numeral 15 is a suction side housing cover, and an oil sump 16 is provided at the bottom. Reference numeral 17 denotes a slinger attached to the female rotor shaft, which splashes the oil in the oil sump 16 and supplies the oil droplet 16a to the suction side bearings 4 and 6. Reference numerals 18 and 19 denote non-contact type suction side shaft seals for the rotating shaft that prevent the oil from entering the working chamber. Bearing chamber 40 and working chamber 30 formed by the suction side housing 8 and the suction side housing cover 15
Is a pressure equalizing hole 2 formed through the suction side housing 8.
0, the recess 31 and the groove 21 provided in the suction side housing cover 15 communicate with each other, and by keeping the pressures around the shaft seals 18 and 19 substantially equal, the shaft seal load is reduced. Further, the opening 21a of the groove 21 formed in the suction side housing cover 15 by casting or machining is arranged on the right side when viewed from the center of the slinger 17 (center of the female rotor shaft) as shown in FIG. The groove 21 extends in the counter-rotational direction from the opening 21a. Therefore, slimba 17 is the third
As shown by the red mark 17a in the figure, it rotates to the right, so there is little oil splash on the right side of the slinger 17 center, and there is no upward splash. In FIG. 3, the upwardly splashed oil droplets generated on the left side of the center of the slimmer 17 are formed by the inner wall 15a formed substantially horizontally on the suction side housing cover 15 so that the pressure equalizing hole 2 is formed.
It is formed so as to shield against 0. This results in groove 2
No splash of oil will enter the pressure equalizing hole 20 from 1 further.

According to the present embodiment, the inner wall of the suction side housing cover 15
Since 15a serves as a shielding plate, the number of parts can be reduced without preparing a special shielding plate unlike the conventional model. Further, since it is not necessary to secure a space for installing the shield plate in the bearing chamber 40, the suction side bearing chamber can be made very compact.

Further, in the case of a casting part, the method of forming the groove on the flange joint surface can be formed at a low cost without requiring machining since it can be easily formed by a casting wooden mold. And it is structurally very simple.

FIG. 4 shows another embodiment in which the groove 21 'has a center line 50.
It is provided so as to extend horizontally to the left (in the figure) beyond, and a pressure equalizing hole 20 'communicates with the end of this groove. According to this, the depth from the opening 21a becomes deeper, and it becomes more difficult for oil to enter.

〔The invention's effect〕

According to the present invention, since it is possible to shield oil splashes into the pressure equalizing holes with a simple structure without installing a special shield plate or the like, it is possible to obtain a very compact and inexpensive oil drainer. it can.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main body of a dry screw vacuum pump according to an embodiment of the present invention, FIG. 2 is a lateral sectional view of the same, and FIG. 3 is a sectional view taken along the line AA of FIG. Is AA of another embodiment
It is an arrow view. 1 ... Male rotor, 2 ... Female rotor, 3 ... Bearing, 4
…… Bearing, 5 …… Bearing, 6 …… Bearing, 7 …… Main housing, 8 …… Suction side housing, 9 …… Timing gear, 10 …… Timing gear, 11 …… Suction port, 12 ……
Discharge port, 13 …… Shaft seal, 14 …… Shaft seal, 15 …… Suction side housing cover, 16 …… Oil sump, 17 …… Slinger, 18…
… Shaft seal, 10 …… Shaft seal, 20 …… Pressure equalizing hole, 21 …… Groove.

Claims (1)

[Claims] 1. A pair of male and female rotors, an oil-bearing bearing for supporting the rotors, a housing for accommodating the rotors, a drive device for the rotors, and a working chamber formed by the rotors and the housings. A vacuum pump for balancing pressures in both chambers by providing a shaft sealing device provided between a bearing chamber accommodating the bearing and a working chamber and means for communicating the bearing chamber and the working chamber side, The means for balancing the pressure in both chambers includes a groove extending in the counter-rotational direction from an opening provided on the suction side housing cover surface forming the bearing chamber and communicating with the bearing chamber, and the groove and the working chamber. An oil draining device for a vacuum pump.