JP2690128B2 - Bearing lubrication device for oil-free screw vacuum pump - Google Patents

Description

The present invention relates to an oil supply device for a suction side bearing of an oil-free screw vacuum pump.

[Conventional technology]

5 and 6 are overall configuration diagrams of a conventional oil-free screw vacuum pump, and FIGS. 7 and 8 are detailed diagrams of a suction side bearing oil supply device thereof. Will be explained. The main body of the oil screw vacuum pump is mainly composed of a pair of intermeshing male rotor 1 and female rotor 2 and a casing 3 surrounding them.
Both rotors are supported by bearings 4 and 5 at both ends.
A power source such as a motor (not shown) for rotating the rotor is
The rotor 1 passing through the timing gear 6 is rotated via a speed increasing gear (not shown). The female rotor 2 rotates together with the timing gear 7 meshed with the timing gear 6, and the rotors rotate without contacting each other.

Gas from a vacuum chamber (not shown) is sucked into the suction port 8 and discharged from the discharge port 9 to the atmosphere. Since the vacuum chamber and the space where the rotor is engaged with each other are in a high vacuum, the rotor shafts 1a and 2a and the casing 3 are prevented from invading gas from the outside.
A shaft seal device (10) is provided between and.

For the lubrication of the bearing, for the discharge side bearing 5,
This is performed by supplying lubricating oil to the oil supply port 11 from an oil pump (not shown). However, the suction side bearing 4
With regard to the above, the slinger 12 is used to splash the lubricating oil in the lubricating oil sump 13. This is because the chamber containing the slinger 12 is close to the high vacuum of the suction chamber, so it is necessary to maintain a high vacuum.However, the oil pump that supplies oil while keeping this chamber at a high vacuum has a complicated structure. Because it becomes expensive.

As shown in FIGS. 7 and 8, the disc-shaped slinger 12 is attached to the suction side end portion of the rotor shaft 2a by the tightening nut 20, and the suction side bearing 4 is fixed. During operation, the slinger 12 rotates in the direction of arrow 14 in FIG.
The oil surface of the lubricating oil sump 13 is flat as shown in Fig. 15 when the vacuum pump is stopped, but when it is operated, the oil surface becomes as shown in Fig. 16 due to viscous friction between the surface of the slinger 12 and the lubricating oil. Get excited. At the same time, oil splashes are scattered, and a part of the oil splashes 17 above the bearing 4 of the casing 3
Then, the fluid is supplied to the bearing 4 from there by a path indicated by an arrow 18.

[Problems to be solved by the invention]

In the above conventional technique, the amount of oil supplied to the suction side bearing 4 cannot be sufficiently secured for the following reason.

That is, only a part of the oil splashes scattered by the slinger 12 is accumulated in the oil receiver 17, and the amount of the oil is so small that the oil supply amount is not sufficient.

Further, even if the lubricating oil that has flowed down from the oil receiver 17 contacts the rolling element of the suction side bearing (roller bearing) 4, the rolling element is rotating at a high speed, so that it is splashed to the slinger 12 side and the rolling surface It is considered that the amount of oil taken in is extremely small.

A first object of the present invention is to supply a sufficient amount of lubricating oil to the oil receiver above the suction side bearing, thereby ensuring a sufficient bearing oil supply amount.

A second object of the present invention is to increase the proportion of the amount of oil that enters the rolling surface of the suction side bearing, thereby making it possible to secure a sufficient amount of bearing oil supply.

[Means for solving the problem]

To achieve the above object, the invention according to claim 1 has a casing, a pair of rotors surrounded by the casing and arranged substantially in parallel, and a pair of rotor shafts for supporting the rotor. 1 for each end of the shaft
A pair of suction-side roller bearings and discharge-side roller bearings are used to support the casing, and a shaft seal device is arranged on the roller shaft closer to the rotor than the roller bearings, and is provided at the suction-side end of the rotor shaft. In a bearing oiling device for an oil-free screw vacuum pump in which a part of a disk-shaped slinger is immersed under the oil surface of a lubricating oil sump, the portion under the oil surface of the outer edge of the slinger and the direction of rotation from the oil surface The space between the pair of suction side roller bearings and the shaft sealing device, and the oil duct that surrounds the rising portion to form a circular arc-shaped lubricating oil passage and the lubricating oil received from the discharge port at the upper part of the oil duct. It is characterized by having an oil receiver leading to the.

[Action]

When the slinger rotates, the lubricating oil in the lubricating oil sump in which the slinger is immersed is dragged into the oil duct from the suction port below the oil surface by viscous friction with the surface of the slinger. The dragged lubricating oil raises the oil level in the oil duct, and eventually the lubricating oil fills the oil duct, and is guided from the upper discharge port of the oil duct to the oil receiver provided in the casing. As a result, a sufficient amount of lubricating oil can be supplied to the oil receiver.

Conventionally, since such an oil duct is not provided,
The lubricating oil was diffused in the lateral direction even if the head was given by viscous friction with the slinger surface, and the oil level 16 shown in FIG. 8 did not become sufficiently high.

Further, when the lubricating oil accumulated in the oil receiver is supplied to the space between the suction side bearing and the shaft sealing device through the lubricating oil passage provided in the casing, the total amount of the lubricating oil supplied from the oil receiver is reduced. Since it flows into the bearing, a sufficient amount of lubricating oil can be supplied to the rolling surface of the bearing.

〔Example〕

FIG. 3 and FIG. 4 are general block diagrams of an oil-free screw vacuum pump according to an embodiment of the present invention. The basic structure of an oil-free screw vacuum pump is shown in Figs.
It is the same as the conventional example shown in FIG.
The parts corresponding to the parts with the same reference numerals in FIG. 6 are shown. Due to the rotation of the male rotor 1 and the female rotor 2, gas from a vacuum chamber (not shown) is sucked into the suction port 8 and discharged from the discharge port 9 to the atmosphere. During operation, a Viscoseal 19 as a shaft sealing device is provided between the rotor shafts 1a and 2a and the casing 3 so that gas from the outside does not enter the rotor engagement space that is in a high vacuum.

The oil is supplied to the intake side bearing 4 by a disc-shaped sunga 12 partially submerged under the oil surface of a lubricating oil sump 13 provided at the end of the rotor shaft on the intake side, and under the oil surface of the outer edge of the slinger. An oil duct 21 that forms an arc-shaped lubricating oil passage that surrounds the part that is immersed in the oil and the part that rises in the direction of rotation from the oil surface.
And an oil receiver 17 for guiding the lubricating oil received from the discharge port 23 in the upper part of the oil duct between the pair of suction side roller bearings and the shaft sealing device.
It is performed by That is, when the roller shaft and the slinger are rotated, the lubricating oil guided upward from the lubricating oil sump 13 through the oil duct 21 is guided by the oil receiver 17 and the lubricating oil passage 25.
Is supplied to the space 26 between the suction-side bearing 4 and the Viscoseal 19 and then supplied from the rear side of the bearing 4 facing the rotor side. The lubricating oil supplied from the back side flows through the bearing to the front side opening on the opposite side, flows through the path indicated by the arrow 27 and is drained to surely lubricate the bearing.

Details of the surrounding structure of the slinger 12 and bearing 4
FIG. 2 and FIG. Disc-shaped slinger 12 is a tightening nut
It is attached to the suction side end of the rotor shaft 2b by 20 and fixes the bearing 4. The oil duct 21 is the second
A circular arc-shaped lubricating oil that surrounds the lower left half of the slinger 12 shown in the figure, that is, the portion immersed in the oil surface 15 at the outer edge of the slinger 12 and the portion rising from the oil surface 15 in the rotation direction (direction of arrow 14). It forms a passage. Suction port 22 of oil duct 21
Is located below the oil surface 15 and the discharge port 23 is located above the oil duct 21 so that oil can be poured from the discharge port 23 to the oil receiver 17 provided in the casing 3. The oil duct 21 is attached to the casing 3 by a fixing means (not shown), and a gap is maintained between the slit portion 24 and the surface of the slinger 12 to the extent that the rotation of the slinger 12 is not hindered.

By providing the oil duct 21 as described above, the slinger 12 is operated so that the lubricating oil in the lubricating oil sump 13 is sucked from the suction port 22 by the viscous friction between the surface of the slinger and the lubricating oil.
Rub inside 21. The dragged-in lubricating oil eventually fills the oil duct 21, and is guided from the discharge port 23 to the oil receiver 17 provided in the casing 3. The lubricating oil once accumulated in the oil receiver 17 passes through the lubricating oil passage 25 provided in the casing 3, and then the space between the suction side bearing 4 and the viscoseal 19.
Supplied to 26. The bisco seal 19 is provided with a screw-shaped groove 19a on the inner peripheral side thereof, and has a pumping action for pushing the lubricating oil to the slinger 21 side when the rotor shaft 2a rotates. Therefore, the entire amount of the lubricating oil supplied from the oil receiver 17 flows through the bearing 4 via the path indicated by the arrow 27,
A sufficient amount of lubricating oil can be supplied to the rolling surface of the bearing 4.

[Effects of the Invention] According to the present invention, the following effects can be obtained. That is, by providing an oil guide that surrounds the outer edge of the slinger and guides the lubricating oil upward, and an oil receiver that guides the lubricating oil from the discharge port above the oil guide to the space between the roller bearing and the shaft sealing device. A sufficient amount of lubricating oil is supplied from the lubricating oil sump to the space between the roller bearing and the shaft sealing device, and the supplied lubricating oil can flow into the roller bearing from the back surface of the roller bearing in its entirety. A sufficient amount of oil for the side roller bearings can be secured. As a result, (1) the temperature of the roller bearing is lowered and the life of the roller bearing is extended.

(2) Since the roller bearings are less worn, it is possible to prevent contact between the rotors and between the rotor and the casing.

(3) Noise and vibration are reduced by reducing the wear of the roller bearing.

And other effects can be expected.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a bearing oiling apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is an oil-free screw vacuum pump according to an embodiment of the present invention. FIG. 4 is a longitudinal sectional view of the conventional oil-free screw vacuum pump, FIG. 6 is a longitudinal sectional view of the conventional oil-free screw vacuum pump, FIG. 6 is a longitudinal sectional view of the same, and FIG. FIG. 8 and FIG. 8 are views taken in the direction of arrow B in FIG. 1 ... Male rotor, 2 ... Female rotor, 1a, 2a ... Rotor shaft, 3 ... Casing, 4 ... Suction side bearing, 5 ... Discharge side bearing, 6 ... Male side timing gear, 7 ... Female side timing gear, 8 ... Intake port, 9
…… Discharge port, 10 …… Shaft sealing device, 11 …… Oil supply port, 12 …… Slinger, 13 …… Lubricating oil sump, 14 …… Slinger rotation direction, 15 …… Oil surface when stopped, 16 …… Oil level during operation, 17 ……
Oil receiver, 18 ... Lubricating oil supply path, 19 ... Viscoseal, 20 ... Tightening nut, 21 ... Oil duct, 22 ... Oil duct inlet, 23 ... Oil duct outlet, 24 ... Oil duct slit, 25 ... Lubricating oil passage, 26 ... Space between bearing and Viscoseal, 27 ... Lubricating oil supply path.

Claims (1)

(57) [Claims] 1. A casing, a pair of rotors surrounded by the casing and arranged substantially parallel to each other, and a pair of rotor shafts for supporting the rotor, and a pair of both ends of each rotor shaft. A disk supported on the casing via the suction side roller bearing and the discharge side roller bearing, the shaft sealing device is arranged on the roller shaft closer to the rotor than the roller bearings, and provided on the suction side end of the rotor shaft. In a bearing oiling device for an oil-free screw vacuum pump, in which a part of a slinger is immersed under the oil surface of a lubricating oil sump, the part under the oil surface of the outer edge of the slinger and the oil surface rise in the direction of rotation. The oil duct that surrounds the curved portion and forms an arc-shaped lubricating oil passage, and the lubricating oil received from the discharge port at the upper part of the oil duct into the space between the pair of suction side roller bearings and the shaft sealing device. A bearing oil supply device for an oil-free screw vacuum pump, which has an oil receiver for guiding.