JP2761486B2 - Circumferential groove vacuum pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial application field The present invention relates to molecular accelerators in industrial vacuum equipment such as particle accelerators, experimental research equipment such as plasma physics, electron microscopes, surface analyzers, and semiconductor manufacturing vacuum equipment. A circumferential groove vacuum pump useful in the region from flow to viscous flow, that is, in the pressure range from high to medium vacuum.

(2) Conventional technology As an example of a conventional vacuum pump, a rotary shaft (c) having a rotary plate (b) in a housing (a) as shown in FIG. Spiral grooves (d) and (d) are formed on both inner surfaces of the housing (a) opposed to both surfaces, and the outer ends of these grooves (d) and (d) are connected to the intake port (e) again. The end communicates with the exhaust port (f), and the gas from the intake port (e) is exhausted from the exhaust port (f) while compressing the gas from the intake port (e) in the grooves (d) and (d) with the rotation of the rotary plate (b). Things are known.

(3) Problems to be Solved by the Invention According to this conventional vacuum pump, spiral grooves (d) and (d) are formed on the inner surface of the housing (a). Since the grooves need to be long, the grooves (d) and (d)
The width of the groove cannot be made large, while on the other hand, if the depth of the groove is made large compared to the width, the exhaust performance is impaired, so that the cross-sectional area of the groove cannot be made large. Considering the multi-stage type to raise, the rotating disk is provided with spiral grooves facing each other and exhausted in parallel, the communication passage to the next stage has a complicated structure, and both surfaces of the rotating disk operate in parallel Therefore, it is difficult to increase the pumping speed, and if the cross-sectional area of the grooves (d) and (d) is increased so as to increase the pumping speed, the rotating disk is correspondingly increased. There is a problem that the diameter of (b) needs to be large and the vacuum pump becomes large.

It is an object of the present invention to solve these problems and to provide a small-sized vacuum pump capable of obtaining a large pumping speed in a region from a molecular flow to a viscous flow.

(4) Means for Solving the Problems In order to achieve this object, the first invention supports a rotating shaft having a rotating disk in a housing having an intake port and an exhaust port, and includes A stator having a recess in which the rotating disk is interposed is fixed, and a notch step is formed in a peripheral portion on both sides of the rotating disk, or an annular groove is formed in a concave portion at a position facing the peripheral portion. Steps or annular grooves are formed in the ventilation passages, and partitions are protruded from the stator in these ventilation passages. The starting end of the ventilation passage on one side of the partition is connected to the intake port by the ventilation on the other side of the partition. According to a second aspect of the present invention, in the first aspect of the present invention, the distance between the rotating disk side and the stator side facing surface in the ventilation path is changed from the start end to the end end. The third invention is characterized in that the intake port and the exhaust A rotating shaft having a plurality of rotating disks is rotatably supported in a housing having a vent, and a stator having a recess in which each of the rotating disks is interposed is fixed in the housing. A notch step is formed in a peripheral portion of the groove or an annular groove is formed in a concave portion at a position opposed to the peripheral portion to form a cut passage or an annular groove in a ventilation passage. In the ventilation path of the adjacent rotating disk, which is protruding, the other end of the partition of the ventilation path of the rotating disk on the intake port side and the starting end of one side of the partition of the ventilation path of the rotating disk on the exhaust port side Are connected to each other by a communication path, and a starting end of the partition wall of the ventilation path of the rotating disk closest to the intake port is communicated with the intake port and the ventilation path of the rotating disk closest to the exhaust port. The other end of the partition wall is communicated with the exhaust port. According to a third aspect of the invention, the distance between the rotating disk side and the facing surface on the stator side in the ventilation path of each of the rotating disks is sequentially reduced from the intake port side to the exhaust port side. .

(5) Function According to the first invention, the gas molecules in the ventilation path produce a transport effect by the molecular drag effect due to gas molecule friction due to both surfaces of the peripheral portion of the rotating disk which rotates at the highest speed and the highest speed. A viscous flow is formed from the molecular flow or the intermediate flow toward the terminal end, and compressed and exhausted at a large exhaust speed from the intake port to the exhaust port.

According to the second invention, the distance b between the surface of the peripheral portion of the rotating disk and the surface of the stator opposed thereto is reduced in response to the increase in the pressure from the start end to the end, and thus, b / λ
(Λ is the mean free path of the gas) keeps a value close to the optimal value,
The compression transport effect is more effectively maintained.

According to the third aspect of the present invention, a considerably large compression ratio can be obtained by sequentially compressing and exhausting gas molecules in the ventilation passage of each rotating disk.

Further, according to the fourth aspect of the invention, the pressure increases as the gas sucked from the largest ventilation path on the intake port side is sequentially pumped into the ventilation path of each rotating disk, and accordingly, b / λ is set to the optimal value. The gas is efficiently compressed in the ventilation passage of each stage having a value of b which keeps a value close to the above, realizing high compression performance with a small number of stages, and increasing the exhaust speed.

(6) Embodiment A first embodiment of the present invention will be described with reference to FIGS.

(1) shows a housing of the vacuum pump, (2) shows a rotating shaft supported in the housing (1), and the rotating shaft (2) has a motor connected at a lower end thereof and an upper end thereof. The rotating disk (3) is fixed at the center boss (3a). Then, the rotating disk (3) was formed with notch steps (4) and (4) by cutting out the peripheral portions on both sides. Reference numeral (5) denotes a stator fixed to the inner surface of the housing (1). The stator (5) has an annular shape in which the rotary disk (3) is interposed at a position corresponding to the rotary disk (3). Recess (6) is formed, and the recess (6) and the notch step (4) are formed.
According to (4), ventilation paths (7) and (7) were formed on both sides of the peripheral portion of the rotating disk (3). And in the recess (6),
A partition (8) obtained by cutting a portion through which the peripheral portion of the rotating disk (3) passes is protruded by the stator (5), and the ventilation paths (7) and (7) are separated by the partition (8). The starting ends of the ventilation paths (7) and (7) on one side of the partition (8), that is, on the upstream side, communicate with the suction port (9) and the partition (8).
The other end, that is, the downstream end of each of the ventilation paths (7) and (7) was connected to the exhaust port (10).

Thus, the rotating disk (3) is driven by the motor so that its peripheral speed is 0.1 to 1.0 times the probability average speed of gas molecules.
When rotated in the direction indicated by the arrow A in the figure, the ventilation channels (7) and (7) are formed around the rotating disk (3). The transport effect occurs due to the molecular drag effect due to the gas molecule friction at this time on both sides of the cutting step portions (4) and (4), which rotate at the highest speed in the peripheral portion of the plate (3). As shown by arrows B in FIGS. 1 and 2, the air passages (7) and (7) are transported from the intake port (9) as shown by arrows C in FIG. 1 and are exhausted by arrows D in FIGS. 1 and 4. (10) It is compressed and evacuated, and has an evacuating action in a pressure range from a molecular flow to a viscous flow. According to the experiment by the inventor, a compression cost of 10 times or more was obtained in the region from the molecular flow to the viscous flow.

5 to 7 show a second embodiment. In this embodiment, the distance between the rotating disk (3) side and the facing surface side of the stator (5) side in the ventilation passages (7) (7) is shown. b was formed so that it gradually became smaller from the start end to the end.

Thus, when the rotating disk (3) is rotated at a high speed as in the first embodiment, the gas in the ventilation passages (7) (7) becomes high in pressure from the start end to the end and becomes an average gas. The free stroke λ becomes small, and b / λ keeps a value close to the optimum value, so that the compression transport effect is more effectively maintained.

FIGS. 8 to 15 show a third embodiment, in which three rotating disks (3)... (3) are connected to a boss (3a).
And the distance between the opposed surfaces of the rotating disk (3) and the stator (5) in the ventilation path of each rotating disk (3) is changed from the intake (9) side to the exhaust port (10). The air passages (7), (7) are formed so as to become smaller in order, and the partition wall (8) protruding from the air passages (7), (7) and the adjacent air passages (7), (7), (7), (7) are further separated. Communicating passage (1
1) is formed by sequentially shifting its position toward the intake port (9) toward the exhaust port (10), and the gas molecules from the intake port (9) are sent through the communication path (11). However, compression is sequentially performed in each of the ventilation paths (7) and (7), and a considerably high compression ratio is obtained. Here, according to the inventor's experiment 10 ³ or more large compression ratio is obtained. Although this embodiment shows the case of three stages, a larger compression ratio can be obtained by constructing more stages.

In each of the above-described embodiments, the cutting steps (4) and (4) are formed on both sides of the periphery of the rotating disk (3). Instead, an annular groove may be formed on the inner surface of the concave portion of the stator (5) facing the peripheral portion.

(7) Advantageous Effects of the Invention According to the first aspect of the present invention, a notch step is formed on the peripheral edge of both surfaces of the rotating disk, or the both surfaces of the rotating disk are recessed in the stator where the rotating disk is interposed. An annular groove is formed at a position facing the peripheral portion of the partition wall to form a ventilation path, and a partition is protrudingly provided in the ventilation path. Since the end of the ventilation path on the other side is communicated with the exhaust port, an effective large intake port can be formed, and gas molecules of both ventilation paths formed around the periphery by the peripheral portion of the rotating disk that rotates particularly fast can be formed. According to the second aspect of the present invention, a large pumping speed can be obtained by generating an efficient transport effect by a molecular drag effect due to gas molecule friction. From the beginning to the end, As the pressure increases, the distance becomes smaller, and thus the b / λ maintains a value close to the optimum value, so that the compression transport effect is more effectively maintained. A plurality of rotating disks are fixed to the shaft, and in the ventilation path of these rotating disks, the starting end of the ventilation path of the adjacent rotating disk and the ending part of the next stage communicate with each other by a communication path, and are closest to the intake port. The start end of the ventilation path of the rotating disk communicates with the intake port, and the end of the ventilation path of the rotating disk closest to the exhaust port communicates with the exhaust port. Since the gas molecules are sequentially compressed and evacuated, a considerably large compression ratio can be obtained. According to the fourth invention, between the opposed surfaces of the rotating disk side and the stator side in the ventilation path of each rotating disk. The distance is gradually reduced from the intake port side to the exhaust port side As a result, the transport effect is increased, the exhaust speed is further increased, and a considerably large compression ratio is obtained. In any of the inventions, ventilation paths are formed on both sides of the peripheral portion of the rotating disk. Since the pressure in the ventilation path is equal on both sides of each part of the rotating disk, it is possible to increase the clearance without requiring a sealing property between the edge of the rotating disk and the inner surface of the concave portion opposed thereto. Thus, high processing accuracy is not required and processing becomes easy, and further, there is an effect that the pump is small in size.

[Brief description of the drawings]

1 is a plan view of a main part of a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line I-II of FIG. 1, and FIG. 3 is a line 0-III of FIG.
FIG. 4 is a sectional view taken along the line 0-IV of FIG. 1, and FIG.
The figure is a sectional view corresponding to FIG. 2 of the second embodiment, FIG. 6 is a sectional view corresponding to FIG. 3 of the same embodiment, and FIG. 7 is a sectional view corresponding to FIG. 4 of the same embodiment. FIG. 8 is a plan view of a main part of the third embodiment, FIG. 9 is a sectional view taken along the line I-II of FIG.
10 is a sectional view taken along the line 0-III of FIG. 8, FIG. 11 is a sectional view taken along the line 0-IV of FIG. 8, FIG. 12 is a sectional view taken along the line 0-V of FIG. Is a sectional view taken along the line 0-VI of FIG. 8, and FIG.
FIG. 15 is a sectional view taken along line 0-VII, FIG. 15 is a sectional view taken along line 0-VIII in FIG. 8, and FIG. 16 is a sectional view of a conventional vacuum pump. (1) Vacuum pump (2) Rotating shaft (3) Rotating disk (4) Cutting step (5) Stator (6) Recess (7) Ventilation path (8) Partition wall (9) Suction port (10) Exhaust port (11) Communication passage

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shoji Iguchi 1221 Kuginodacho, Hachioji-shi, Tokyo Inside the Osaka Vacuum, Ltd. Hachioji Plant (56) References JP-A-60-116895 (JP, A) Sho Akai Kai 48-15606 (JP, U)

Claims (4)

(57) [Claims] A rotating shaft having a rotating disk in a housing having an intake port and an exhaust port, and a stator having a recess in which the rotating disk is interposed is fixed in the housing; A notch step is formed in the peripheral portion on both sides of the rotating disk, or an annular groove is formed in a concave portion at a position opposed to these peripheral portions, and the notch step portion or the annular groove is formed in a ventilation path, and these ventilation paths are formed. A partition wall protrudes from the stator, and a starting end of the ventilation path on one side of the partition wall communicates with the intake port, and a terminal end of the ventilation path on the other side of the partition wall communicates with the exhaust port. Circumferential groove vacuum pump. 2. The method according to claim 1, wherein the distance between the opposed surfaces of the rotating disk and the stator in the ventilation path is gradually reduced from a starting end to an end. A circumferential groove vacuum pump as described. 3. A rotating shaft having a plurality of rotating disks is rotatably supported in a housing having an intake port and an exhaust port.
A stator having a concave portion in which each of the rotary disks is interposed is fixed, and a notch step portion is formed in a peripheral portion on both sides of the rotary disk, or an annular groove is formed in a concave portion at a position opposed to these peripheral portions. A notch step or an annular groove is formed in a ventilation path, and a partition wall is protruded from the stator in these ventilation paths. In the ventilation path of the adjacent rotating disk, other partition walls of the ventilation path of the rotating disk on the intake port side are provided. The end of the side and the start of the partition of the ventilation path of the rotating disk on the exhaust port side are connected by a communication path, and one side of the partition of the ventilation path of the rotating disk closest to the intake port. A circular groove vacuum pump characterized in that a start end of the circular groove is communicated with the intake port and an end of the rotating disk closest to the exhaust port on the other side of the partition wall is communicated with the exhaust port. 4. The distance between the rotating disk side and the facing surface on the stator side in the ventilation path of each of the rotating disks is gradually reduced from the intake port side to the exhaust port side. The circumferential groove vacuum pump according to claim 3, wherein: