JPH03130593A - Shaft sealing device for vacuum pump or blower for gas - Google Patents

Abstract

PURPOSE:To prevent burning by connecting a grease supply hole with a drain hole in a shaft sealing space part provided in a housing at the axial front and back of a shaft bearing for supporting a rotary shaft, fixing an overshooting means at the rotary shaft, and renewing grease forcedly. CONSTITUTION:Shaft sealing space parts 12, 12 are formed on the side of a housing 1 at the axial front and back of a shaft bearing 7 for supporting a rotary shaft 3 freely rotatably. A plurality of oil seals 11 are planted in each space part 12 on the side of the housing 1, and an ultra-rigid alloy contact ring 10 is engaged in the corresponding part of the rotary shaft 3. A grease supply hole 13 communicating with the shaft sealing space part 12 are connected with a drain hole 15. A circular overshooting means 21 is planted at the center of a seal collar 9 fixed to the rotary shaft 3 at the shaft sealing space part 12. Grease in the shaft sealing space part 12 is agitated by recess parts 21a and protruding parts 21b of the overshooting means 21 to be renewed forcedly by rotation of the rotary shaft 3. Carbonization of the grease can thus be prevented, and burning is prevented, thereby the durability of a shaft sealing device and grease is improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a sealing device for a gas vacuum pump or blower, and the j@1 invention relates to a sealing device for a gas vacuum pump or blower, and the j@1 invention is for sealing a rotor shaft of a vacuum pump or blower in a shaft-sealing space in a housing. It is surrounded by grease that can be replaced within the unit, and the grease is forced to be reversed repeatedly. The second invention relates to an invention having the same subject matter as the first invention, in which the first invention is specified and the shaft sealing device and the bearing are provided only on one side, making it suitable for applying relatively high vacuum or high pressure. The third invention is a further improvement of the shaking tool of the first and second inventions.

(Prior Art and Problems) A shaft sealing device is known in which a housing is provided with a shaft sealing space filled with grease that surrounds the outer periphery of a rotor shaft inserted into the housing of a gas vacuum pump or blower. However, this shaft sealing device has the drawback that the grease fed into the space rapidly heats up and deteriorates as the rotor shaft rotates at high speed, and the carbide of the grease is baked onto the rotor shaft. Such burning can lead to poor sealing of the rotor shaft and poor precision. This poses a problem that must be improved.

(Problems to be Solved and Objects of the Invention) The above drawbacks are presumed to be due to the fact that the shaft sealing grease surrounding the surface of the rotor shaft does not change until it is replaced. The present invention aims to solve this problem.

(Means for Solving the Problems) A first aspect of the shaft sealing device for a gas vacuum pump or blower of the present invention provides a housing with an annular groove surrounding the outer periphery of a rotor shaft, and a peripheral wall of the annular groove, A vacuum pump or blower comprising an oil seal fixed to the peripheral wall and placed in contact with the outer periphery of the rotor shaft and arranged at the front and rear of the shaft in the axial direction, and having a shaft seal space in which the grease supply hole and the grease drain hole are communicated. In this method, a shaker is provided which rotates together with the shaft in the shaft seal space when the oil seals at the front and rear in the axial direction of the rotor shaft are opened, and the grease is forcibly reversed by the shaker in the shaft seal space. This is a characteristic feature. Further, a second invention is characterized in that one set of the shaft sealing device of the first invention is provided on each of the front side and the rear side of a bearing installed in the housing and supporting the rotor shaft, This improves the shaft sealing effect of the invention. The third invention is #S1, characterized in that the shaking tool of the second invention is provided with a shaking convex part or a shaking concave part on both sides or one side, and the second and third inventions are characterized in that The field of application and problem to be solved by the first invention and the second invention are the same.

A preferred embodiment of the invention will now be described.

(Example) Reference numeral 1 denotes a housing fixed to the side of a casing (not shown), and the rotor shaft 3 of the Roots rotor 2 arranged inside the casing is passed through the shaft insertion hole 4 of the housing 1. It is supported by a ball bearing 17 provided in the 4. The shaft insertion hole 4 has a first enlarged diameter portion 6 which is enlarged in diameter following the neck 5 through which the labyrinth 8 of the rotor shaft 3 is inserted.
(the annular groove of the present invention) is formed, followed by a second enlarged diameter part 7, and the seal collar 9 is fitted onto the rotor shaft 3 so as to match the first enlarged diameter part (annular groove) 6. , an oil seal 11.11 made of ethylene tetrachloride fixed to the peripheral wall 6b of the first enlarged diameter portion (annular groove) 6 is brought into contact with the outer periphery of the shaft 3, and is opposed in the axial direction of the shaft 3. established,
Cemented carbide contact ring (hardened part) on the outer periphery of seal collar 9
10, 10 with the oil seal 11.11, thereby forming a shaft sealing space surrounded by the peripheral wall 6b of the first enlarged diameter portion (annular groove) 6, the oil seal 11.11, and the outer peripheral surface of the seal collar 9. A grease supply hole 13 of the housing 1 in which a grease nipple 14 is provided in the space 12 communicates with a drain hole 15 provided with a drain opening/closing valve 16.

The present invention provides shaft sealing devices 20 on both sides of the bearing 17.
can be provided one set at a time. FIG. 1 shows this aspect. The shaft sealing device 20 on the right side of the figure is an oil seal 11.1.
1 differs in shape and shape from the one on the left, but this is within the scope of the invention.

On the outer circumferential surface of the seal collar 9, a disc-shaped cutout 14:21 is provided which projects between the oil seals 11 and 11 of the sleeve sealing space 12 and rotates together with the rotor shaft 3. This furikiri soldier 21 can be integrally formed with the resin seal collar 9 by slightly tilting about half its circumference in one direction, but as shown in FIG.
I! (It may be provided on one side), or as shown in FIG. 3, several cut-off recesses 21a are provided on both sides or one side.

Figure 4 shows the rotor shaft diameter 50IIlfiφ, 200
Regarding vacuum pumps with 0 times per minute (per minute), ■Dry operation (no oil) shaft sealing device, however, there are two oil seals, ■Two oil shaft sealing devices, however, two oil seals, ■
This is a report card comparing the shaft sealing effects of a single mechanical seal type Tsumugi u device, ■ a double mechanical seal type shaft seal device, ■ a shaft seal device of the present invention, but a set of shaft seal devices, and 4008r in the time column. , 1.000) 1r.

5, 0OOHr, and 10,000Hr indicate the time measured by a leakage meter based on the time of starting operation. “lO
Numbers such as -'Torre/5eCJ are vacuum engineering terms and are commonly used to indicate the amount of leakage of a vacuum pump. is ideal.

According to this table, the vacuum pump equipped with the shaft sealing device of the present invention is 5
, 00011r, and it can be seen that there is no shaft sealing device comparable to the present invention.

(Operations and Effects) In the first aspect of the present invention, an annular groove 6 surrounding the outer periphery of the rotor shaft 3 is provided in the housing 1, and a peripheral wall 6b of the annular groove,
and oil seals 11.11 fixed to the peripheral wall 6b and placed in contact with the outer periphery of the rotor shaft 3 in the axial direction of the shaft 3, and communicating the grease supply hole 13 and the grease drain hole 15. In a vacuum pump or blower equipped with a sealed space 12, the rotor shaft 3
Between the front and rear oil seals 11 and 11, there is provided a shaker 21 which rotates together with the shaft 3 in the shaft seal space 12. Since the rotor shaft 3 is configured to repeat
By constantly forcibly renewing the shaft sealing grease that contacts the outer periphery of the shaft sealing device, the shaft sealing device and shaft sealing grease can be maintained without causing decomposition aging due to frictional heat, burning of carbides, and poor sealing or precision of the rotor shaft due to the burning. It has the effect of improving the durability of.

The second invention has a configuration in which one set of the shaft sealing devices 20 is provided on each of the front and rear sides of the bearing 17 that supports the rotor shaft 3 passed through the housing 1 when the vacuum is relatively high.
This has the effect of increasing the effect of the first invention.

The third invention further strengthens the forced reversal of the shaft sealing grease of the first and second inventions by providing a shaft convex portion 21a or a shaft seal 4@21b on both sides or one side of the shaft seal 21, thereby sealing the shaft. It has the effect of further improving the durability of shaft sealing grease.

From the experimental results shown in Figure 4, it can be proven that the effect of the present invention is great.The reason for this is that the vacuum pump is a single-shaft rotary pump or a two-shaft Roots pump, both of which are positive displacement, so torque fluctuations are large. Therefore, the vibration of the pump is large, ranging from 5μ to 20μ (microns), and the followability of the lip of the oil seal is poor.In addition, the surface tension of the oil is small, and it is minimized by the vacuum force, so the vibration on the vacuum side is It is thought that the shaft sealing performance is poor due to the inflow of air and oil, but since the viscosity of the grease filling is high and the surface tension is large, if deterioration and carbonization are prevented by stirring, the shaft sealing performance will be stable over the long term. can be maintained, and the result is shown in Figure 4 (■).

[Brief explanation of the drawing]

Figures 1 to 3 of the attached drawings show an embodiment of the present invention, in which Figure 1 is a longitudinal sectional front view of the housing, Figures 2 and 3 are perspective views of the seal collar 9, and Figure #c4 is a report card. It is. 1 → Haunong 3 → Rotor shaft 6 → First enlarged diameter part (annular groove) 6a → Side wall 6b → Peripheral wall
9 → Seal collar 10.10 → Cemented carbide contact ring (hardened part) 11.11
→Oil seal 12→Shaft seal space 13→Grease supply hole 15→Grease drain hole 17→Ball bearing 20
→ Axis IT device 21 → Furikiri soldier 21a → Furikiri recess 21b → Furikiri convex part

Claims (1)

[Scope of Claims] 1) An annular groove surrounding the outer circumference of the rotor shaft is provided in the housing, and an annular groove is fixed to the circumferential wall of the annular groove and is fixed to the circumferential wall so as to be in contact with the outer circumference of the rotor shaft and arranged at the front and rear of the shaft in the axial direction. In a vacuum pump or blower that is configured with an oil seal and has a shaft seal space that communicates a grease supply hole and a grease drain hole, the rotor shaft is integrated with the shaft in the shaft seal space between the front and rear oil seals of the rotor shaft. 1. A shaft sealing device for a gas vacuum pump or blower, characterized in that a rotating shaker is provided and the grease is repeatedly forcibly reversed within a shaft sealing space by the shaker. 2) When the vacuum is relatively high, the shaft sealing device is provided on the front or rear side of the bearing that supports the rotor shaft passed through the housing, and when the vacuum is relatively low, it is provided on only one of the bearings. A shaft sealing device for a gas vacuum pump or blower according to claim 1. 3) A shaft sealing device for a gas vacuum pump or blower as claimed in Claims 1 and 2, characterized in that a cutting protrusion or a cutting recess is provided on both sides or one side of the cutting tool.