JPH06147184A - Vacuum pump - Google Patents

Abstract

PURPOSE:To improve the transfer and compression performance of gas molecules by providing a rotor and a stator with a high working accuracy and little run-out. CONSTITUTION:A rotor shaft 2 is positioned in the center of the interior of a casing 1, and a rotary disc 3 supported at the center thereof is directly mounted on the rotor shaft 2. A fixed disc 4 supported at the outer peripheral part thereof is mounted on the inner periphery of the casing 1. The fixed disc 4 and the rotary disc 3 are alternately disposed adjacent to each other in the axial direction of the rotor shaft 2. Further, an exhaust hole 3a deflected in the opposite direction to the rotating direction is opened on the periphery of the rotary disc 3. On the other hand, an exhaust hole 4a deflected in the opposite direction to that of the exhaust hole 3a provided on the rotary disc 3 is opened on the periphery of the fixed disc 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum pump that rotates a rotor shaft at high speed and compresses and transfers gas in the axial direction of the rotor shaft to suck and exhaust gas. The present invention relates to a vacuum pump which is provided with a disk-shaped rotating disk and a fixed disk, which are provided, to improve transfer and compression performance of gas molecules.

[0002]

2. Description of the Related Art Conventionally, this type of vacuum pump has a large number of strip-shaped rotary blades which are cantilevered on the outer circumference of a rotor shaft as a rotating body and a strip which is cantilevered on the inner circumference of a casing as a fixed body. A large number of fixed blades are arranged, and the rotary blades and the fixed blades are alternately arranged close to each other in the axial direction of the rotor shaft.

FIG. 3 is a plan view showing the entire rotary blade, in which the rotary blade 10 rotates in the direction of the arrow.

In FIG. 1, a strip-shaped rotary blade 10 has a side surface 10a inclined in the direction opposite to the rotation direction when viewed from above the paper surface, and an end surface 10b facing the fixed blade in the radial direction of the rotor shaft 11. The rotor shaft 11 is supported in a cantilever manner at a predetermined inclination angle so as to be horizontal, and the space sandwiched between the side surfaces 10a serves as a gas flow passage.

On the other hand, a fixed blade (not shown) also has the rotary blade 10 described above.
Similarly to the strip shape, the fixed blade has a side surface inclined in a direction opposite to the side surface 10a of the rotary blade 10,
It is cantilevered at a predetermined inclination angle on the inner circumference of the casing, and a gap sandwiched between both blades is formed by making the end surfaces of the fixed blade and the rotary blade 10 face each other.
In the conventional vacuum pump configured as described above, the rotor shaft 11 is rotated at a high speed to rotate the rotating blade 10 at a speed close to the moving speed of gas molecules, so that the rotating blade 1
The tilt angle provided at 0 gives momentum in the exhaust direction to the gas molecules on the blade orbit.

On the other hand, the fixed blade has a slit structure S provided with an inclination having an inclination opposite to that of the rotary blade 10 so that gas molecules given momentum by the rotary blade 10 can be positively transferred and compressed in the exhaust direction. (See Figure 3).

In the conventional vacuum pump based on such an operating principle, a plurality of rotary blades 10 and fixed blades are alternately stacked as described above, but the gap between the rotary blades 10 and the fixed blades is reduced. , It is necessary to inject gas molecules into the fixed blade without attenuating the momentum given by the rotating blade (the same applies to the incident from the fixed blade at the next stage to the rotating blade 10), and especially the friction between gas molecules Is large, and the need for it is high in the middle and low vacuum regions where the momentum is greatly attenuated.

[0008]

However, in the above-mentioned conventional vacuum pump, the rotary blades and the fixed blades are cantilevered with a predetermined inclination angle, while the end faces of the rotary blades and the fixed blades must be kept horizontal. However, it is extremely difficult to machine the end faces of the blades with the inclination angle horizontally, so the machining accuracy is poor. There is a limit to what you can do.

Further, since the rotary blades and the fixed blades are supported in a cantilever shape in a strip shape, the rigidity thereof is weak. Especially, when the rotary blades are rotated at a high speed, the free ends of the rotary blades are caused by load fluctuations and the like in the axial direction of the rotor shaft. There is a possibility that both blades may come into contact with each other because of a large swing, and therefore the gap between both blades can be reduced only to a certain extent. From this point as well, there is a problem that gas molecule transfer and compression performance cannot be improved.

Therefore, according to the present invention, by forming the blades supported by the rotor shaft and the casing in a disk shape, respectively, the processing accuracy is excellent and the vibration is reduced to improve the transfer and compression performance of gas molecules. It is an object of the present invention to provide a vacuum pump designed for the purpose.

[0011]

In order to achieve the above object, the invention according to claim 1 is cantilevered on the outer circumference of the rotor shaft located inside the casing, and has a large number of exhaust holes on the circumference. The rotating disk provided is a disk-shaped rotating disk and a disk-shaped fixed disk that is cantilevered on the inner circumference of the casing and has a large number of exhaust holes on the circumference. It is characterized in that the plates and the fixed discs are alternately arranged close to each other in the axial direction of the rotor shaft.

In order to achieve the above object, the invention according to claim 2 is such that the exhaust hole provided in the rotating disk is opened while being deflected in a direction opposite to the rotation direction of the rotor shaft. The exhaust hole provided in the fixed disk is deflected in the opposite direction to the exhaust hole provided in the rotating disk and opened.

[0013]

According to the first aspect of the invention, since the rotating disk and the fixed disk mounted on the rotor shaft and the casing are formed in a disk shape, it is easy to perform horizontal processing on the disk. The rotating discs and the fixed discs can be arranged alternately as close as possible.

Further, since the rotary disc and the fixed disc are disc-shaped, they have high rigidity, and therefore, even if the load fluctuation or the like becomes large, the deflection of both discs can be suppressed as small as possible. You can

According to the second aspect of the present invention, when the rotor shaft rotates at high speed, gas molecules are incident on the exhaust holes provided in the rotating disk and the fixed disk, and the gas holes are inclined to the incident gas molecules. By giving momentum in the exhaust direction by the surface, gas molecules can be transferred from the intake side toward the exhaust side.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the vacuum pump according to the present invention will be described in detail below with reference to FIGS.

FIG. 1A is a partially cutaway side view showing the inside of the vacuum pump according to this embodiment, and FIG.
[FIG. 4] is a plan view showing a part of a rotating disc according to the present embodiment. In this figure, a vacuum pump comprises a cylindrical casing 1, a rotor shaft 2 located in the center of the inside of the casing 1, a disc-shaped rotating disc 3 whose cantilevered portion is supported on the outer periphery of the rotor shaft 2, and a casing. 1 is provided with a fixed disk 4 in the shape of a disk whose outer peripheral portion is supported in a cantilever manner.
And the fixed discs 4 are alternately arranged close to each other in the axial direction of the rotor shaft 2.

A large number of exhaust holes 3a and 4a are provided on the circumferences of the rotary disk 3 and the fixed disk 4, respectively.

The rotating disk 3 shown in FIG. 1 (b)
1A is cut away in FIG. 1A, and the fixed disk 4 is also cut out in FIG. 1A. Further, in FIG. 1B, although only a part of the exhaust holes 3a provided on the circumference of the rotary disk 3 is shown, these exhaust holes 3a are provided on the entire circumference. It is natural.

The casing 1 has an intake port (not shown) on the upstream side in the flow direction shown in FIG. 1A and an exhaust port (not shown) on the downstream side, and the rotor shaft 2 includes a motor (not shown). The drive means rotates in the rotation direction shown in FIG. Next, the rotating disk 3 will be described with reference to FIG.

FIG. 2 (a) is a plan view showing the entire rotary disc 3 according to this embodiment, and FIG. 2 (b) is one exhaust gas provided on the rotary disc 3. As shown in FIG. It is a perspective view showing the path of the hole 3a, and (c) of the same figure is a partially cutaway side view showing the side surface of the rotating disk 3.

2 (a), the exhaust hole 3a
2 is shown only in part, and the BB 'portion shown in FIG. 2 (a) is cut away in FIG. 2 (c). In this figure, the rotating disc 3 has a large number of exhaust holes 3a randomly distributed on the entire circumference, and a hollow portion 3b is formed in the central portion as a portion directly attached to the rotor shaft 2.

The exhaust hole 3a is opened by being deflected in the direction opposite to the rotating direction of the rotor shaft 2. More specifically, as shown in FIG. 2 (b), the path of the exhaust hole 3a is along the circumference, and a predetermined direction is set in the direction opposite to the rotation direction of the rotor shaft with respect to the thickness direction of the rotating disk 3. The opening is formed with an inclination angle.

Next, the fixed disc 4 will be described with reference to FIG. 1. The fixed disc 4 is also provided with a large number of exhaust holes 4a randomly distributed on the entire circumference like the rotary disc 3 described above. At the same time, the exhaust hole 4a is opened by being deflected in the opposite direction to the exhaust hole 3a provided in the rotary disc 3. More specifically, the path of the exhaust hole 4a is
An opening is formed along the circumference at a predetermined inclination angle in the forward direction with respect to the rotation direction of the rotor shaft with respect to the thickness direction of the fixed disk 4.

Next, the operation of the vacuum pump of this embodiment is shown in FIG.
(A), first, the rotor shaft 2 is rotated at a high speed to rotate the rotating disk 3 at a speed close to the moving speed of gas molecules, so that the exhaust hole 3a of the rotating disk 3 is present. Momentum in the evacuation direction is given to the gas molecules that perform.

Then, the gas molecules given a momentum in the exhaust direction are incident on the exhaust hole 4a of the fixed disc 4 arranged opposite to the rotating disc 3, and at this time, the gas molecules are in the rotating disc 3.
And the fixed disc 4 are adjacent to each other while the damping of the momentum is suppressed and incident, and the exhaust hole 4a of the fixed disc 4 deflected in the opposite direction to the rotating disc 3 further advances in the exhaust direction to positively. Is transferred to and compressed.

Such movement of the gas molecules is repeatedly performed in the rotating disk 3 and the fixed disk 4 which are alternately arranged close to each other, so that the gas molecules finally existing on the intake side are almost eliminated. State, that is, a vacuum state is reached, and suction and exhaust are completed.

[0028]

As is apparent from the above description, according to the first aspect of the present invention, the rotating disk and the fixed disk mounted on the rotor shaft and the casing are respectively disc-shaped. , It is easy to machine the opposite surfaces of both discs horizontally, and the machining accuracy can be improved. Therefore, it is possible to place both discs alternately closer to each other than the conventional strip-shaped wing body. You can

Further, since the rotary disc and the fixed disc are disc-shaped, they have a higher rigidity than the conventional strip-shaped blade body, and in particular, the rotary disc rotates at a high speed to cause large load fluctuations. Since the shaking is small and there is no possibility that both discs contact each other, it is possible to arrange both discs as close as possible from this point.

That is, according to the invention of claim 1,
Since the gap between the rotating disc and the fixed disc can be set as small as possible, it is possible to prevent the momentum of gas molecules from being attenuated in this gap and improve the transfer and compression performance of gas molecules. You can

In particular, in the medium and low vacuum regions where the friction between gas molecules is large and the momentum is greatly attenuated, the great effect is exhibited by the reduction of the gap, so that a wide range from high vacuum to low vacuum is achieved. A vacuum pump with a high compression ratio can be obtained.

According to the second aspect of the present invention, the gas molecules entering the exhaust holes of the rotating disk and the fixed disk are given momentum in the exhaust direction by the inclined surface of the exhaust holes, and Since the gas molecules to which the momentum is given efficiently flow from the intake side to the exhaust side, it is possible to further improve the transfer and compression performance of the gas molecules.

[Brief description of drawings]

1A is a partially cutaway side view showing the inside of a vacuum pump according to this embodiment, and FIG. 1B is a plan view showing a part of a rotating disk according to this embodiment. .

FIG. 2A is a plan view showing an entire rotary disc according to the present embodiment, and FIG. 2B is a perspective view showing a path of an exhaust hole provided in the rotary disc. Yes, (c) is a partially cutaway side view showing the side surface of the rotating disk.

FIG. 3 is a plan view showing the entire conventional rotary blade.

[Explanation of symbols]

 1 Casing 2 Rotor Shaft 3 Rotating Disc 3a Exhaust Hole 4 Fixed Disc 4a Exhaust Hole 10 Rotor Blade S Slit Structure

Claims (2)

[Claims] 1. A disc-shaped rotating disc, which is cantilevered on the outer periphery of a rotor shaft located inside the casing and has a large number of exhaust holes on the circumference, and a disc on the inner periphery of the casing. A fixed disk in the form of a disk that is held and supported and has a large number of exhaust holes on the circumference; and the rotating disk and the fixed disk are alternately arranged close to each other in the axial direction of the rotor shaft. A vacuum pump characterized by being arranged. 2. The exhaust hole provided in the rotating disk is opened by being deflected in a direction opposite to the rotation direction of the rotor shaft, and the exhaust hole provided in the fixed disk is provided in the rotating disk. 2. The vacuum pump according to claim 1, wherein the vacuum pump is opened while being deflected in a direction opposite to an exhaust hole provided in the plate.