JPH0223297A - Circular groove vacuum pump - Google Patents

Abstract

PURPOSE:To provide high exhaust speed over the region from a molecular flow to viscous flow by providing a partition wall projecting from a stator in a ventilating path to afford communication between the leading end of the ventilating path at the one side of the partition wall and an intake port and between the trailing end of same path at the other side and an exhaust port. CONSTITUTION:A rotary disk 3 is rotated in the direction of arrow A by driving a motor with as high as 0.1-1.0 time the probability average speed of the peripheral speed of gas molecules. Then, since ventilating paths 7, 7 are formed in the peripheral part of the rotary disk 3, gas molecules in these ventilating paths 7, 7 collide with both surfaces of notch step portions 4, 4 of the rotary disk 3 rotating with the highest speed to produce a transportation effect by a molecular drag effect due to gas molecule friction. The gas molecules are thus transported from an intake port 9 as shown by the arrow b through the ventilating paths 7, 7 as shown by the arrow C and compressed and exhausted from an exhaust port 10 as shown by the arrow D so that the gas molecules have an exhaust action in the pressure region from the molecular flow to the viscous flow.

Description

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

(2) Prior art As an example of a conventional vacuum pump, the housing (a
) in which a rotating shaft (C) having a rotating plate (b) is pivotally supported, and spiral grooves (d) (d ) and these grooves (
d) The outer end of (d) is connected to the intake port (e) and the inner end is communicated to the exhaust port (f), so that the gas from the intake port (e) is communicated with the rotation of the rotary plate (b). It is known that the compressor is compressed in the groove (d) (d) and exhausted from the exhaust port (f).

(3) Problems to be solved by the invention According to this conventional vacuum pump, spiral grooves (d) (d) are formed on the inner surface of the housing (a), and in order to improve compression performance. Because the groove needs to be long, the width of the groove (d) (d) cannot be increased, and on the other hand, making the depth of the groove larger than the width impairs exhaust performance, so the cross-sectional area of the groove is However, when considering a multi-stage system to increase the compression ratio, it is difficult to connect spiral grooves to the next stage with a parallel exhaust system with opposing spiral grooves on both sides of the rotating disc. Since the passage has a complicated structure and it is impossible to operate both sides of the rotating disk in parallel, it is difficult to increase the exhaust speed. ci)
When the cross-sectional area of the rotating disk (b) is increased, the rotating disk (b)
The problem was that the diameter of the vacuum pump had to be increased, making the vacuum pump large.

An object of the present invention is to solve these problems and provide a small-sized vacuum pump that can obtain a high pumping speed in a range from molecular flow to viscous flow.

(4) Means for solving the problem In order to achieve this object, the first invention pivots a rotating shaft having a rotating disk within a housing having an intake port and an exhaust port, and
A stator having four parts in which the rotating disk is inserted is fixed in the housing, and cut steps are formed in the peripheral parts of both sides of the rotating disk, or annular grooves are formed in the recesses at positions opposite to these peripheral parts. and forming these cut steps or annular grooves into ventilation passages,
Partition walls are provided in these ventilation passages protruding from the stator, and a starting end of the ventilation passage on one side of the partition wall communicates with the intake port, and a terminal end of the ventilation passage on the other side of the partition wall communicates with the exhaust port. A second invention is characterized in that in the first invention, the distance between opposing surfaces of the rotating disk side and the stator side in the ventilation passage is gradually reduced from the starting end to the terminal end, A third aspect of the present invention is that in the first aspect, a plurality of partition walls are provided in the ventilation passage projecting from the stator at equal intervals in the circumferential direction, and a starting end of the ventilation passage on one side of each of these partition walls is connected to the intake port. The fourth invention is characterized in that the terminal end of the ventilation passage on the other side of each of these partitions is communicated with the exhaust port, and a fourth invention provides a rotating device having a plurality of rotating disks in a housing having an intake port and an exhaust port. In addition to supporting the shaft, a stator having a recessed portion in which each of these rotating disks is inserted is fixed in the housing, and notch steps are provided at the periphery of both sides of these rotating disks or facing these periphery portions. An annular groove is formed in the recess at the position where the cut step or annular groove is formed to form a ventilation passage, and a partition wall is provided protruding from the stator in these ventilation passages, and an inlet is formed in the ventilation passage of the adjacent rotating disk. A communicating passage connects the other end of the partition wall of the ventilation passage of the rotary disk on the side and the starting end of the partition on one side of the ventilation passage of the rotation disk on the exhaust port side, and A starting end on one side of the partition of the ventilation passage of the rotating disk closest to the rotating disk was communicated with the intake port, and a terminal end of the other side of the partition of the ventilation path of the rotating disk closest to the exhaust port was communicated with the exhaust port. Further, a fifth invention is characterized in that in the fourth invention, the distance between opposing surfaces of the rotating disc side and the stator side in the ventilation passage of each rotating disc is sequentially arranged from the intake port side to the exhaust port side. It is characterized by being made small,
In a sixth aspect of the present invention, in the first aspect or the fourth aspect, the wall thickness of the peripheral portion of the rotating disk is made thinner as the outer position thereof increases, and the opposing surfaces of the rotating disk side and the stator side in the ventilation passage are provided. The feature is that the distance between them is constant in the radial direction.

(5) Effect According to the first invention, the gas molecules in the ventilation path are transported by the molecular drag effect due to the friction of the gas molecules by both surfaces of the peripheral portion that rotates and moves at the highest speed in the rotating disk that rotates at high speed, and from the starting end. Toward the terminal end, the molecular flow or intermediate flow becomes a viscous flow, which is compressed and exhausted from the intake port toward the exhaust port at a high exhaust speed.

Further, according to the second invention, as the pressure increases from the starting end toward the terminal end, the distance between the peripheral surface of the rotating disk and the opposing surface of the stator decreases. teb/
The gas input (λ is the mean free path of the gas) is maintained close to the optimum value, and the transport effect is further increased, the exhaust speed is further increased, and the exhaust gas compression performance is also improved.

Furthermore, according to the third aspect of the invention, gas molecules can be exhausted from each ventilation path partitioned by a plurality of partition walls, increasing the exhaust speed.

Further, according to the fourth aspect of the invention, gas molecules are sequentially compressed and exhausted in the ventilation passages of each rotating disk, and a considerably large compression ratio can be obtained.

Furthermore, according to the fifth invention, as the gas sucked in from the ventilation passage on the side of the largest intake port is sequentially pumped into the ventilation passages of each rotating disk, the pressure increases, and b/λ corresponds to the optimum value. The gas is efficiently compressed in the ventilation passages of each stage where the value of b is kept close to , and high compression performance can be achieved with a small number of stages, and the exhaust speed can also be increased.

Further, according to the sixth invention, the maximum value of the centrifugal stress acting on the center of the rotating disk is small, and thus the rotating disk does not require a material with high strength.

(6) Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

(1) shows the casing of the vacuum pump, and (2) shows a rotating shaft supported within the casing (1). The rotating shaft (2) is connected to a motor at its lower end, and its upper end A rotating disk (3) is fixed at a boss portion (3a) in the center thereof. The rotating disk (3) was cut out at the peripheral portions of both sides to form cut step portions (4) (4). Further, (5) indicates a stator fixed to the inner surface of the housing (1), and the stator (5) has an annular shape in which the rotating disk (3) is inserted at a position corresponding to the rotating disk (3). A recess (6) is formed, and the recess (6) and the cut step (4)=
By (4), ventilation passages (7) (7) were formed on both sides of the peripheral portion of the rotating disk (3). And in the recess (6),
A partition wall (8) with a portion through which the peripheral portion of the rotating disk (3) passes is cut out and protrudes from the stator (5).
The ventilation passages (7) (7) are separated by the partition wall (8).
The starting ends of these ventilation passages (7) (7) on one side, that is, the upstream side of the partition wall (8), are communicated with the suction port (9), and the starting ends of these ventilation passages (7) (7) on the other side, that is, the downstream side, of the partition wall (8) are communicated with the suction port (9). 7) was connected to the exhaust port (10).

Thus, when the rotating disk (3) is driven by the motor and rotated in the direction of arrow A in Fig. 1 at a circumferential speed of 0.1 to 1.0 times the probability average speed of gas molecules, the ventilation path (7) (7
) are formed at the periphery of the rotating disk (3), so the gas molecules in these ventilation passages (7) (7) are distributed at the notch step portion, which rotates at the highest speed, at the periphery of the rotating disk (3). (4) When the gas molecules hit both sides of (4), a transport effect occurs due to the molecular drag effect caused by the friction of the gas molecules, and thus the gas molecules move from the inlet (9) as shown by arrow B in Figures 1 and 2. The ventilation passages (7) (7) are transported as shown by arrow C in Figure 1.
It is compressed and evacuated from the exhaust port (10) as indicated by the arrow in FIG. 4 and has an exhaust effect in the pressure range from molecular flow to viscous flow. According to the inventor's experiments, a compression ratio of 10 times or more was obtained in the range from a single molecule flow to a viscous flow.

5 to 7 show a second embodiment, in which the rotating disk (3) in the ventilation passage (7) (7)
The distance between the facing surfaces on the stator (5) side and the stator (5) side was formed so as to gradually become smaller from the starting end toward the ending end. Thus, when the rotating disk (3) is rotated at high speed as in the first embodiment, the pressure of the gas in the ventilation passages (7) increases from the starting end to the ending end, and the average pressure of the gas increases. The free stroke entry becomes small, and accordingly, as mentioned above, the ventilation passage (7
) (7) gradually becomes smaller, so that b/λ remains close to the optimum value, further increasing the transport effect and improving exhaust gas compression performance.

FIG. 8 to FIG. 10 show a third embodiment, in which a notch step (4) on the periphery of the rotary disk (3) is shown.
The thickness of the part (4) is gradually made thinner as it goes outward, and the distance between these notch steps (4) (4) and the inner surface of the recess (6) facing them is also The recesses (6) are formed so that they are equal at any position in the radial direction, and the intervals become narrower as they go outward, thus making the notches in the peripheral part of the rotary disk (3) narrower. Stepped section (4
) Since the wall thickness at the point in (4) gradually decreases toward the outside, even if the rotating disk (3) rotates at high speed, the maximum value of the centrifugal stress that acts on its center. becomes small,
Therefore, the rotating disk (3) is not required to have considerable strength, and the rotating disk (3) may be made of engineering plastics, ceramics, or cast materials.

Further, FIGS. 11 to 14 show a fourth embodiment, in which the intake port (9) and the exhaust port (10) are provided at two locations with an interval of 180 degrees, and a partition wall is provided accordingly. (8) is also provided in two places, thus partition wall (
8) Two ventilation channels separated by (8) (7) (7
), the gas molecules are compressed and exhausted, so the pumping speed is approximately doubled. In this embodiment, there are two partition walls (8).
An example is shown in which the ventilation passage (7) (7) is divided into two sides, but the ventilation passage (7) (7) is divided by three or more partition walls (8).
may be divided into three or more locations.

Furthermore, FIGS. 15 to 22 show a fifth embodiment, and the fifth embodiment
In the example, three rotating disks (3)...(3)
are formed into a single piece at the boss portion (3a), and the distance between the facing surfaces of the rotating disk (3) side and the stator (5) side in the ventilation passage of each rotating disk (3) is set to the air intake port (9) side. The ventilation passages (7) (7) are formed so as to become smaller in size as they reach the exhaust port (10) side, and are further provided with partition walls (8) projecting from these ventilation passages (7) (7).
And the communication path (11) that communicates between the adjacent ventilation paths (7) (7) and (7) (7) is connected from the intake port (9) side to the exhaust port (
10), the positions of which are sequentially shifted as they reach the side, so that gas molecules from the intake port (9) flow through the communication path (11).
While being sent through the air passages (7), the air is sequentially compressed in each ventilation passage (7), resulting in a considerably high compression ratio. According to the inventor's experiments, a large compression ratio of 10' or more was obtained. Although this embodiment shows the case of three stages, an even larger compression ratio can be obtained by configuring a larger number of stages.

Furthermore, in all of the embodiments described above, the cut steps (4) (4) are formed by cutting both sides of the peripheral portion 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) Effects of the Invention As described above, according to the first invention, the cut steps are formed on the peripheral edges of both sides of the rotating disk, or the recesses of the stator in which the rotating disk is inserted are formed on both sides of the rotating disk. An annular groove is formed at a position facing the peripheral portion of the partition wall to form a ventilation passage, a partition wall is provided protruding from the ventilation passage, and the starting end of the ventilation passage on one side of the partition wall is used as an intake port. Since the end of the ventilation passage on the other side is communicated with the exhaust port, an effective large intake port can be formed, and gas molecules in the ventilation passage formed in the peripheral part of the rotating disk, which rotates at a particularly high speed, can be The molecular drag effect caused by the friction of gas molecules produces an efficient transport effect and a large exhaust speed can be obtained, and according to the second invention, the distance between the opposing surfaces of the rotating disk side and the stator side in the ventilation passage is set to the starting point. Since the distance is gradually decreased from the beginning to the end, the distance becomes smaller as the pressure increases toward the beginning and end, and thus b/in remains close to the optimum value. Furthermore, according to the third aspect of the present invention, the ventilation passages are partitioned by a plurality of partition walls at equal intervals in the circumferential direction, and the starting end of each partitioned ventilation passage is connected to an intake port. Furthermore, since the terminal end is communicated with the exhaust port, it is possible to exhaust air through each ventilation path, increasing the exhaust speed.According to the fourth aspect of the invention, a plurality of rotating disks can be connected to the same rotating shaft. are fixed, and in the ventilation passages of these rotating disks, the starting ends of the ventilation passages of adjacent rotating disks and the terminal ends of the next stage are connected through communication passages, and the starting ends of the ventilation passages of the rotating disks closest to the intake ports are connected. The terminal portion of the rotary disk ventilation passage closest to the exhaust port is communicated with the exhaust port.

Since the gas molecules are sequentially compressed and exhausted in each ventilation passage by a rotating disk rotating at high speed, a considerably large compression ratio can be obtained. Since the distance between the opposing surfaces of the plate side and the stator side is formed so that it becomes smaller sequentially from the intake port side to the exhaust port side, the transport effect increases and the exhaust speed becomes even higher, and it becomes considerably faster. According to the sixth invention, the thickness of the peripheral part of the rotating disk is gradually thinned toward the outside, so that even if the rotating disk is rotated at high speed, it will not act on the center part. The maximum value of centrifugal stress is small, and thus the rotating disk does not need to be made of particularly strong materials, and can be manufactured using inexpensive materials and processing methods, and it is also possible to use corrosion-resistant materials. Also, in both inventions, ventilation passages are formed on both sides of the peripheral portion of the rotating disc, and the pressure in both air passages is equal on both sides of each part of the rotating disc, so that the air passages are formed on both sides of the peripheral part of the rotating disc. It is possible to increase the clearance between the pump and the inner surface of the concave portion without requiring sealing performance, and thus, high processing accuracy is not required, making processing easier, and furthermore, the pump can be made smaller.

[Brief explanation of the drawing]

1 is a plan view of the main part of the first embodiment of the present invention, FIG. 2 is a sectional view taken along the knee line in FIG. 1, and FIG. 4 is a cross-sectional view of the 0-rllr line in FIG. 1; the cross-sectional view is a cross-sectional view corresponding to FIG. 2 of the second embodiment;
The figure is a cross-sectional view corresponding to FIG. 3 of the same embodiment, FIG. 7 is a cross-sectional view corresponding to FIG. 4 of the same embodiment, and FIG. 8 is a cross-sectional view corresponding to FIG. 2 of the third embodiment. 9 is a cross-sectional view corresponding to FIG. 3 of the same embodiment, FIG. 10 is a cross-sectional view corresponding to FIG. 4 of the same embodiment, and FIG. 11 is a main part of the fourth embodiment. Fig. 12 is a plan view of Fig. 11;
14 is a sectional view taken along the line V-VI in FIG. 11, FIG. 15 is a plan view of the main part of the fifth embodiment, and FIG. 15 is a sectional view taken along the line I-II. FIG. 17 is a sectional view taken along the line om in FIG.
19 is a sectional view taken along the 0-IT line in FIG. 5.
20 is a sectional view taken along the 0-VI line in FIG. 15, FIG. 21 is a sectional view taken along the O-■ line in FIG. 15, and FIG. 22 is a sectional view taken along the 0-■ line in FIG. 15. FIG. 23 is a sectional view of a conventional vacuum pump. Figure 20 (1)...Vacuum pump (2)...Rotating shaft (3)...Rotating disk (4)...Notch step (5)...Stator (6)...・Concavity (7)...Ventilation passage (8)...Partition wall (9)...Intake port (10)...Outlet port (11)...Communication path Figure 21 Applicant: Osaka Vacuum Co., Ltd. Equipment manufacturing facility Fig. 22 Fig. 23

Claims (6)

[Claims] (1) A rotating shaft having a rotating disk is pivotally supported in a housing having an intake port and an exhaust port, and a stator having a recess in which the rotating disk is inserted is fixed in the housing, and the rotating shaft is Cut steps or annular grooves are formed in the periphery of both sides of the plate or annular grooves are formed in the recesses located opposite these peripheries to form ventilation passages, and partition walls are provided in these ventilation passages. A circumference projecting from the stator, the starting end of the ventilation passage on one side of the partition wall communicating with the intake port, and the terminal end of the ventilation passage on the other side of the partition wall communicating with the exhaust port. groove vacuum pump. (2) A circle according to claim 1, characterized in that the distance between opposing surfaces of the rotating disk side and the stator side in the ventilation passage is gradually reduced from the starting end to the terminal end thereof. Circumferential groove vacuum pump. (3) A plurality of partition walls are provided in the ventilation passage protruding from the stator at equal intervals in the circumferential direction, and the starting end of the ventilation passage on one side of each of these partition walls is set as the intake port, and the other partition walls of each of these partition walls are 2. The circumferential groove vacuum pump according to claim 1, wherein a terminal end of said ventilation passage is connected to said exhaust port. (4) A rotary shaft having a plurality of rotating disks is pivotally supported within a housing having an intake port and an exhaust port, and a stator having a recessed portion in which each of these rotating disks is inserted is fixed within the housing, Cut steps or annular grooves are formed in the peripheries of both sides of these rotating disks or annular grooves are formed in the recesses at positions opposite to these peripheries to form ventilation passages. A partition wall is provided protruding from the stator, and in the ventilation passages of adjacent rotating discs, the other end of the partition wall of the ventilation passage of the rotating disc on the intake port side and the partition wall of the ventilation passage of the rotating disc on the exhaust port side. A starting end on one side of the partition wall of the rotary disk that is closest to the intake port is connected to the starting end on one side of the rotating disk by a communication passage, and a starting end on the first side of the partition wall of the ventilation passage of the rotating disk closest to the intake port is connected to the intake port and the starting end of the partition wall on the first side is closest to the exhaust port. A circumferential groove vacuum pump characterized in that the other end of the partition wall of the ventilation passage of the rotating disk is communicated with the exhaust port. (5) The distance between the opposing surfaces of the rotating disk side and the stator side in the ventilation passage of each rotating disk is configured to become smaller sequentially from the intake port side to the exhaust port side. A circumferential groove vacuum pump according to claim 4. (6) The wall thickness of the peripheral portion of the rotating disk is made thinner as the outer position increases, and the distance between opposing surfaces on the rotating disk side and the stator side in the ventilation passage is made constant in the radial direction. Claim 1 or 4 characterized in that
Circumferential groove vacuum pump as described in section.