JPH066946B2 - Gas vacuum pump or blower shaft seal device - Google Patents

Description

The present invention relates to a vacuum pump for gas or a blower shaft sealing device, and a first invention is to install a rotor shaft of a vacuum pump or blower in a shaft sealing space in a housing. The grease is surrounded by grease that can be replaced, and the forced inversion of the grease is repeated. The second invention relates to the invention of the same object as the first invention in which the first invention is provided as a specific invention and is provided only on one of the shaft sealing device and the bearing in order to apply a relatively high vacuum or high pressure. The third invention is a further improvement of the shaker of the first and second inventions.

(Prior Art and Problems) A shaft seal device in which a housing is provided with a grease-filled shaft seal space surrounding the outer circumference of a rotor shaft inserted into a gas vacuum pump or blower housing is known. However, this shaft sealing device has the drawback that the grease fed into the space rapidly deteriorates as the rotor shaft rotates at high speed, and carbide of grease is seized on the rotor shaft. However, there is a problem that this must be improved.

(Problems to be Solved and Object of the Present Invention) It is presumed that the above-mentioned drawbacks are due to the fact that the shaft sealing grease surrounding the surface of the rotor shaft does not change until a replacement operation is performed. It is an object of the present invention to solve this problem, and an object thereof.

(Means for Solving the Problems) A first invention of a shaft sealing device for a gas vacuum pump or a blower according to the present invention is provided with an annular groove surrounding the outer periphery of a rotor shaft in a housing, and a peripheral wall of the annular groove, and In a vacuum pump or blower that is fixed to the peripheral wall and is in contact with the outer circumference of the rotor shaft and is constituted by oil seals arranged in the axial front and rear of the shaft, and that includes a shaft sealing space portion that communicates the grease supply hole and the grease drain hole, Between the oil seals on the front and rear sides of the rotor shaft, a shaker that integrally rotates with the shaft in the shaft-sealing space is provided, and the force-reversal of the grease is repeated by the shaker in the shaft-sealing space. It is a thing. A second invention is characterized in that one set of the shaft sealing device of the first invention is provided on each of a front side and a rear side of a bearing installed in a housing to support a rotor shaft. The shaft sealing effect of the invention is improved. A third invention is characterized in that a shake-off convex portion or a shake-off concave portion is provided on both surfaces or one side of the shake-off tool of the first and second inventions, and the second and third inventions are specified. The first and second inventions, which are inventions, have the same fields of use and problems to be solved.

A preferred embodiment of the present invention will be described below.

(Embodiment) 1 is a housing fixed to a side portion of a casing (not shown). A rotor shaft 3 of a roots rotor 2 arranged inside the casing is passed through a shaft insertion hole 4 of the housing 1, and the shaft insertion hole is formed. It is supported by a ball bearing 17 provided in the inside of No. 4. In the shaft insertion hole 4, a first expanded diameter portion 6 (annular groove of the present invention) having an expanded diameter is formed following the neck 5 through which the labyrinth 8 of the rotor shaft 3 is inserted, and subsequently, the second expanded diameter portion 7 is formed. An oil made of tetrafluoroethylene which is provided, is fitted with the seal collar 9 on the rotor shaft 3 so as to match the first expanded diameter portion (annular groove) 6, and is fixed to the peripheral wall 6b of the first expanded diameter portion (annular groove) 6. The seals 11 and 11 are provided in contact with the outer periphery of the shaft 3 so as to face the shaft 3 in the axial direction.
Cemented carbide contact ring (hardened part) on the outer periphery of the seal collar 9
A shaft sealing space surrounded by the oil seals 11 and 11 coming into contact with the oil seals 10 and 10, and thereby surrounded by the peripheral wall 6b of the first expanded diameter portion (annular groove) 6 and the oil seals 11 and 11 and the outer peripheral surface of the seal collar 9. The housing 12 is provided with a space 12, and the space 12 is connected to the grease supply hole 13 of the housing 1 having the grease nipple 14 and the drain hole 15 provided with the drain opening / closing valve 16.

In the present invention, the shaft sealing device 20 is provided on both sides of the bearing 17.
Can be provided one by one. The mode is shown in FIG. The shaft seal device 20 on the right side of the drawing is an oil seal 11, 1.
Although the shape and number of is different from the one on the left, this is within the scope of the invention.

On the outer peripheral surface of the seal collar 9, there is provided a disk-shaped deviator 21 which projects in the middle of the oil seals 11 of the shaft sealing space 12 and rotates together with the rotor shaft 3. The shaker 21 can be integrally formed with the resin seal collar 9 by slightly tilting about half the circumference in one direction, but as shown in FIG. 2, several shake-off convex portions 21b are provided on both sides (even on one side). Good) or as shown in FIG.
Several a's are provided on each side or one side.

Fig. 4 shows a vacuum pump with a rotor shaft diameter of 50 mmφ and a rotation speed of 2000 (per minute), dry operation (without oil) shaft seal device, but one oil seal, oil type shaft seal device, but oil seal It is a result table comparing the shaft sealing effect of two, a single mechanical seal type shaft sealing device, a double mechanical seal type shaft sealing device, the shaft sealing device of the present invention, but one set of shaft sealing devices. 40
0Hr, 1.000Hr, 5.000Hr, 10.000Hr indicate the time measured by the leak measuring instrument with reference to the time of operation start. "10 ^-1
Numbers such as "Torr / sec" are vacuum engineering terms and are commonly used to express the leak amount of a vacuum pump. Ideally, "10 ^-3 Torr / sec" or "10 ^-4 Torr / sec" is used. And

According to this table, the vacuum pump provided with the shaft sealing device of the present invention is 5.
It can be seen that the shaft seal is perfect up to 000 Hr, and there is no shaft seal device comparable to the present invention.

(Operation and Effect) According to the first aspect of the present invention, the housing 1 is provided with the annular groove 6 surrounding the outer circumference of the rotor shaft 3, and the peripheral wall 6b of the annular groove is provided.
A shaft which is fixed to the peripheral wall 6b and is in contact with the outer circumference of the rotor shaft 3 and is constituted by oil seals 11 arranged in front and rear in the axial direction of the shaft 3 and which connects the grease supply hole 13 and the grease drain hole 15 to each other. In the vacuum pump or blower including the sealed space portion 12, the rotor shaft 3
A shaker 21 that integrally rotates with the shaft 3 in the shaft-sealing space 12 is provided between the front and rear oil seals 11, 11 in the shaft-sealing space 12 to forcefully invert the grease. Rotor shaft 3 because of the repeated construction
The shaft sealing grease contacting the outer circumference of the shaft is constantly forcibly renewed to prevent decomposition and aging due to frictional heat, seizure of carbides, poor sealing of the rotor shaft due to the seizure, and poor accuracy. Has the effect of improving durability.

The second aspect of the invention has a structure in which one set of the shaft sealing device 20 is provided on the front side and the rear side of the bearing 17 that supports the rotor shaft 3 that is passed through the housing 1 when the vacuum is relatively high.
There is an effect that the effect of the first invention can be increased.

A third aspect of the present invention is to provide a shake-off convex portion 21a or a shake-off concave portion 21b on both sides or one side of the shake-off device 21 to further enhance the forced sealing reversal of the shaft-sealing grease of the first and second inventions, and to achieve a shaft-sealing effect. It has the effect of further improving the durability of the shaft seal grease.

From the experimental results shown in FIG. 4, it can be proved that the effect of the present invention is large, because the vacuum pump is a single-axis rotary pump or a twin-axis roots pump and both are positive displacement, so that the torque fluctuation is large. Therefore, the vibration of the shaft is as large as 5μ to 20μ (micron), the followability of the oil seal lip is poor, and in addition, the surface tension of the oil is small and it becomes the smallest due to the vacuum force. It is considered that oil will flow in and the shaft sealing performance will be low, but since grease filling has a high viscosity and a large surface tension, stable shaft sealing performance will be maintained for a long time if deterioration and carbonization due to stirring are prevented. It is possible, and the result is shown in Fig. 4.

[Brief description of drawings]

1 to 3 of the accompanying drawings show an embodiment of the present invention. FIG. 1 is a vertical sectional front view of a housing, FIGS. 2 and 3 are perspective views of a seal collar 9, and FIG. Is. 1-> housing 3-> rotor shaft 6-> first expanded portion (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 Sealing space 13 → Grease supply hole 15 → Grease drain hole 17 → Ball bearing 20 → Shaft sealing device 21 → Shaking tool 21a → Shaking recess 21b → Shaking convex

Claims (3)

[Claims] 1. A housing is provided with an annular groove surrounding the outer circumference of a rotor shaft, and a peripheral wall of the annular groove, and an oil seal fixed to the peripheral wall and brought into contact with the outer circumference of the rotor shaft and arranged in the axial front and rear of the shaft. In a vacuum pump or blower having a shaft-sealing space that communicates the grease supply hole and the grease-drain hole, a vibration that integrally rotates in the shaft-sealing space with the front and rear oil seals of the rotor shaft. A shaft seal device for a gas vacuum pump or blower, characterized by comprising a cutter and repeating forcibly reversing grease by the shaker within the shaft sealing space. 2. The shaft sealing device is provided on the front side or the rear side of a bearing supporting the rotor shaft passed through the housing when the vacuum is relatively high, and is used by being provided on only one of the bearings when the vacuum is relatively low. A vacuum pump for gas or a shaft sealing device for a blower according to claim 1. 3. A vacuum pump for gas or a shaft sealing device for a blower according to claim 1, wherein a shake-off convex portion or a shake-off concave portion is provided on both sides or one side of the shake-off tool. .