JPS60243394A - Turbo molecular pump - Google Patents

Abstract

PURPOSE:To improve an exhaust speed performance by a method wherein a turbine wheel body, constituted integrally of a plurality of turbine wheels having larger thickness and pitch than the turbine wheels in the group of turbine wheels, is arranged in a turbo molecular pump and stator rings are projected from the peripheral wall of the turbine wheel body into ring grooves. CONSTITUTION:A plurality of turbine wheels 5a, having thickness and pitch different from the upper turbine wheels 2a, 3a, are formed on the outer peripheral surface of the turbine wheel body 5 fixed to a driving shaft 1 while the turbine wheels 5a are provided with spiral grooves 5b so that the depth of the groove becomes shallow as the position thereof approaches the side of an exhaust port B and with the stator ring 8 in the ring grooves 5c at positions opposing to the ring grooves 5c on a peripheral wall surrounding the turbine wheel body 5 with a minute clearance. According to this method, prominent exhaust speed performance may be developed even in the area of low vacuum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J The present invention is also excellent in the low vacuum region. It concerns a turbomolecular pop that can exhibit tJl pneumatic velocity performance.

[Conventional technology 1 A turbo molecular pop is constructed by arranging a rotor chord (rotating rhombus) that has an inclination and a stake structure (fixed blade) that has an opposite direction. It is a device that mechanically blows out and exhausts gas momme 1 by Manto group, super, +;
4I's ability to achieve true luxury is a feature.

However, since the reduction ratio of this kind of conventional pump in the Daito group is low, there is a problem in that the pumping performance is extremely low in the low vacuum region when the operation stop I is set to 1.

In other words, in the low vacuum region, the pumping speed becomes almost nothing in the low vacuum region, and therefore there is the trouble of having to use a multi-stage fat II auxiliary vacuum pump.

[Problems to be Solved by the Invention] In view of the current situation, the present invention seeks to provide a turbomolecular pump that continuously exhibits excellent pumping speed performance from a high vacuum region to a low vacuum region.

[Means for Solving the Problems] The turbomolecular pump of the present invention is equipped with a Daito group in which rotor blades and stakes are alternately arranged on the intake side, and a spiral groove on the outer periphery on the exhaust port side. Provide a ring groove 11; 1 χ
A rough ilj body is provided which integrally constitutes the Daito, which is thicker and has a larger pinch than the '74' tj of the Φ group, and a stator ring is protruded into the ring groove from the peripheral wall surrounding this E II body. and configure.

[Function] In other words, with such a device, the gas molecules released from the blade wheel group are guided and discharged along the long path created by the spiral groove of the blade wheel body, and at the same time, the gas molecules are guided and discharged from the ring groove. acts as a node that stops the reverse flow of molecules, and the compression ratio of the molecular flow is crystallized.

[Example 1 Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 illustrate an example of the configuration of a turbomolecular pump according to the present invention. This turbomolecular pump has its intake 1
A configuration is provided in which the IA side is provided with a group of impellers made up of a combination of the rotor 2 and the stator 3, while the exhaust port B side is provided with a impeller body 5 connected to the exhaust port B side. First, the blade wheel group (</, H) in the figure has rotor blades 2a projecting radially from the outer periphery at a predetermined angle of inclination, and its base end 2b.
4 is placed in the center I and press-fitted onto the drive shaft 1, and the shaft 11 is pressed into place.
- A rotor 2 that is cleaned 1N in multiple stages, and a stator blade 3a having an inclination angle opposite to that of the rotor blade 2a of this rotor 2, and one rotor to the right. The stator 3 is positioned and fixed with its proximal end 3b sandwiched between spacers 4.4 stacked on the inner peripheral surface of the outer frame 6 from the outer periphery surrounding the stator 3, and the four wings 2a and 3a are intersected. It is arranged and configured in various locations.

When such a group of impellers rotates at high speed by driving the rotor blades 2a, they collide with gas molecules and change the amount of interlocking in the axial direction, causing cooperation with the stator blades 3a. If
The ff action includes the action of forcibly generating and exhausting air from the intake air (core A force) at one end toward the exhaust port B at the other end.

On the other hand, the blade wheel body 5 located at the corner in the figure is connected to the drive shaft 1-h with its L end adjacent to the upper end of the blade group. A drive shaft I passes through the drive shaft 1 and is fixed to the drive shaft 1 so as to be rotated at high speed together with the rotor 2.

Then, on the outer circumferential surface of the blade 14 body 5, there are a plurality of impellers 5a, 5 whose thicknesses are slightly different from those of the impeller groups 2a, 3a on the L side.
A. A fist e is formed. This impeller 5a is manufactured as follows. That is, an appropriate number of helical grooves 5b connect one end of the first end and the second end, and are formed so that the groove depth gradually becomes shallower toward the exhaust port B side, although not clearly shown in the illustrated example. , 5b/e disputes are provided. The direction of this spiral 5b is +ii with respect to the rotational direction of the drive shaft l.
It is formed in a direction in which the gas molecules discharged from the groups 2a, 3a are led out to the exhaust port B side along the grooves 5b. At the same time, ring grooves 5C15C, . This ring groove 5C is usually provided in multiple stages at equal intervals,
Moreover, each independent ring groove 5C is made to be proportional to the change in the groove depth of the spiral groove 5b, and is not clearly shown in the illustrated example, or the groove depth is made shallower for the F stage. It is adjusted and formed. In this case, the groove depth of each ring groove 50 is the intersecting helix fI.
The groove depth is formed to be deeper than that of groove 5b. In this way, each of the impellers 5a of the integral part 5 of the mold is integrally constructed with a larger thickness and width than each of the impellers of the impeller groups 2a and 3a of 1-force. . A spiral groove 5b and a ring groove 5C are provided on the outer circumferential surface of the pawn seven body 5.
A large number of intersecting portions C are created by intersecting each other and having a depth matching the groove depth of the ring groove 5C.

On the other hand, spacers 7, 7, . . . fitted in multiple stages on the inner circumferential surface of the outer frame 6, which surrounds the blade wheel body 5 with a minute gap, that is, in the example not shown, correspond to the ring grooves 50. A stator ring 8 is provided protrudingly within the ring groove 5C at the position where the stator ring 8 is located. This stator ring 8 has its outer circumferential portion 8a sandwiched between the spacers 7.7 and is positioned and fixed, and its inner circumferential edge is brought close to the groove bottom of the link groove 5C to partition the ring groove 5C in the axial direction. It is arranged like this. Also, the spacer 7.7 of the stator ring 8
The inner peripheral part protruding from the inner surface is as shown in FIG.
Suriato 8b having an inclination angle of 41 opposite to the spiral groove 5b
are opened radially and provided with a plurality of plates 8c in the circumferential direction.

Next, the operation of this turbomolecular pump will be explained.

The drive shaft 1 is rotationally driven by a motor built in one side, and the rotor 2 and the blade wheel body 5 of the shaft 1F- are rotated at high speed and put into operation. Then, as mentioned above, the intake u
The gas molecules taken in from A are forcibly passed through large and medium groups A, and then guided to each spiral groove 5b of the blade wheel body 5. Here, each impeller 5a of the impeller body 5 rotating at high speed
gives the colliding gas component I- a speed of movement in the circumferential direction along the spiral groove 5b, compressing it and creating a molecular flow toward the exhaust r, +B side, but at this time, the spiral groove 5b
11. Role of n points to prevent reverse flow of molecular flow at each intersection point C of l. It will be demonstrated to the fullest. In other words, if the wing Φ body 5 does not have the link groove 50, there is no obstruction in the middle of the long spiral groove that blocks the flow of molecular flow, and therefore there is no obstruction in the groove. Is it possible that the transfer of gas molecules IυJ in the above-mentioned ring groove 50 is reversible?
The helical grooves 5b of each formula Φ5a are connected to /i- through the +Ni slits 8b which are closed by the blades 8C of the stator ring 8 and have an inclination in the opposite direction to the helical grooves 5b. Therefore, each intersection C can serve as a node that reverses the flow of molecules. Each spiral groove 5b has a large number of intersections (n
Point) C is interposed between the helical grooves 5b and the link groove 5cc7) The groove depth of the helical groove 5b in relation to the stator lick 8 whose protrusion length is extended according to the groove depth at this intersection C. Since the groove will be blocked to a deeper depth than the previous one, there will be no risk of backflow occurring even if the pump exhausts the air to near its ultimate limit pressure.

At the same time, in this case, the outer wall surface of each impeller 5a of the impeller body 5 and the fl 8 C of the stator ring 8 provided with the slit 8b are as if the rotor X2a and the stator body 3a constituting the Daito group Like Phase 71-, it functions to mechanically blow gas molecules in the i/° direction, so it is extremely effective for maintaining the pump's pumping characteristics. Become.

1-1 One example has been explained, but the theory of L
In order to further enhance the effect of the backflow prevention 11 mentioned in Section 1, the stator ring 8 has spiral grooves 8d and 8e in opposite directions on its human side, as shown in Fig. 3. You can also do it like this.

In addition, in the example of the figure collar, convenience-1-the spiral groove 5
b, 5b --- and ring grooves 5c, 5 cm @e are made smaller than those of Kumite, but in practice, it is also possible to provide them narrower and more densely. That is, large 1 (5a
The goal is to make the pitch smaller.

Further, the angle of each spiral groove 5b and the interval between each ring groove 5C can be freely adjusted. For example, ring full 5c, 5c phase jI
It is also possible to increase the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by increasing the compression efficiency of the blade wheel body 5 by a further increase.

Effect 4 of the Invention Since the present invention has the configuration described above, t8! ! Equipped with a honey compression ratio increasing means with a mechanism, it exhibits the desired pumping speed performance even in the low vacuum region and achieves high speeds without decreasing the 1'↓+ degree. This is what the performance turbo minute-r pump was able to provide.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main part of a turbomolecular pump according to an embodiment of the present invention. FIG. 2 is a partially broken perspective view showing the appearance of the stator ring. FIG. 3 is a partially cut away perspective view of the stator ring in a smaller modified example. ■... φ drive shaft, 2a... rotor quality 3a... stator blade, 5... impeller body 5ae impeller, 5b-Φ spiral groove 50... ring groove, 6... outside Frame 8...Statoric 800/Intake port, B/Yu-Exhaust [1 Agent Patent attorney Hiroshi Akazawa

Claims (1)

[Claims] The intake CI side is equipped with a group of impellers arranged in a relationship between the rotor blades and the stake bearings, and the exhaust side is equipped with a spiral 11 on the outer periphery.
4 and ring grooves are provided, and the row 11 of the Daito group (with a larger thickness and a large central body integrally composed of a plurality of binar or manmade impellers) is installed, and from the peripheral wall surrounding this impeller body. A turbo molecular pop characterized in that a stator nog is inserted and sunk into the ring groove.