Rotor shaft and stator for dry vacuum pump and dry vacuum pump

Abstract

The utility model provides a rotor shaft and a stator for a dry vacuum pump and the dry vacuum pump, and belongs to the technical field of vacuum pumps. The rotor shaft is provided with a plurality of rotor mounting parts which are distributed at intervals along the length direction of the rotor shaft and are used for mounting multi-stage rotors, and air passing channel parts which are positioned between any two adjacent rotor mounting parts; at least one outer air passing groove is formed in the middle area of the outer wall of at least one air passing channel part. The air passing channel part and the inner wall of the stator shaft hole can form an air passing channel, and the outer air passing groove enables a gap in the middle area of the air passing channel to change, so that when compressed air generated by meshing of an upper-stage rotor flows to a cavity of a lower-stage rotor through the air passing channel, oscillation purging airflow is formed, and the compressed air is blown into the cavity of the lower-stage rotor. The processing objects accumulated on the surface of the gas passing channel fall off due to the fluctuation of the pulse gas and flow to the next-stage cavity along with the gas, so that the problems that the processing objects of the gas passing channel are easy to accumulate and are not easy to clean and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vacuum pumps, and in particular relates to a rotor shaft and a stator for a dry vacuum pump, and a dry vacuum pump. Background Art

[0002] A dry vacuum pump is a pump that can start pumping air from atmospheric pressure and discharge the pumped gas directly into the atmosphere. There is no oil or other working medium in the pump chamber. Compared with ordinary oil pumps, this can reduce the pollution of final products such as chips, medicines, and food, reduce the amount of oil used, save energy and protect the environment, and prevent the vacuum chamber from being affected by water vapor, dust, or particles, thereby enhancing the reliability of the vacuum pump.

[0003] The current claw-type dry vacuum pump has a fixed gap in the air passage between the rotor shaft and the stator hole wall. During operation, the gas compressed in the upper chamber will pass through the air passage between the outer wall of the rotor shaft and the inner wall of the stator hole and enter the next compression chamber, and finally be discharged through the exhaust hole on the stator.

[0004] Based on the fixed gap of the gas passage between the rotor shaft and the stator hole, during operation, when the gas flows through the gas passage, process materials will be accompanied by the gas, and these process materials will adhere to the surface of the gas passage. Although some process materials will flow through the next cavity with the exhaust, a small amount of process materials will still accumulate on the surface of the gas passage. As the working time goes by, the accumulation of process materials in the gas passage increases, resulting in a smaller gap in the gas passage, poor exhaust, and insufficient vacuum bottom pressure. In severe cases, the rotor and the process materials rub and heat up, the temperature is too high, and the rotor shaft diameter expands thermally, which further leads to friction, interference, and shutdown between the rotor shaft and the stator hole. Utility Model Content

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a rotor shaft and a stator for a dry vacuum pump, and a dry vacuum pump.

[0006] In one aspect of the present disclosure, a rotor shaft for a dry vacuum pump is provided, wherein the rotor shaft has a plurality of rotor mounting portions for mounting a multi-stage rotor and spaced apart along its length direction, and a gas passage portion located between any two adjacent rotor mounting portions; wherein:

[0007] At least one outer air passage groove is provided in the middle area of ​​the outer wall of at least one of the air passage portions;

[0008] The air passage portion can form an air passage with the inner wall of the stator shaft hole, and the outer air passage groove changes the gap in the middle area of ​​the air passage, so that when the compressed gas generated by the meshing of the upper-stage rotor flows through the air passage to the cavity of the next-stage rotor, an oscillating purge airflow is formed.

[0009] Optionally, the outer air passage groove is circumferentially arranged around the outer wall of the rotor shaft.

[0010] Optionally, a width of the at least one outer gas transition groove is less than or equal to 1 / 3 of a width of the gas transition channel portion.

[0011] Optionally, the depth of the outer air passage groove is 0.1-0.15 mm.

[0012] Optionally, a gap in a middle region of the gas passage is larger than gaps in regions on both sides.

[0013] Another aspect of the present disclosure provides a stator for a dry vacuum pump, wherein the stator has a plurality of cavities for accommodating a multi-stage rotor and spaced apart along its length, and an axial hole between any two adjacent cavities; wherein:

[0014] At least one inner air passage groove is provided in the middle area of ​​the inner wall of at least one of the shaft holes;

[0015] The inner wall of the stator shaft hole can form an air passage with the air passage portion on the rotor shaft, and the inner air passage groove changes the gap in the middle area of ​​the air passage, so that when the compressed gas generated by the meshing of the previous stage rotor flows through the air passage to the next stage rotor cavity, an oscillating purge airflow is formed.

[0016] Optionally, the inner air passage groove is circumferentially arranged around the inner wall of the stator shaft hole.

[0017] Optionally, the width of the at least one inner air passage groove is less than or equal to 1 / 3 of the width of the stator shaft hole.

[0018] Optionally, the inner air passage groove has a depth of 0.1 to 0.15 mm.

[0019] In another aspect of the present disclosure, a dry vacuum pump is provided, wherein the dry vacuum pump comprises a stator, a multi-stage rotor and two rotor shafts; wherein:

[0020] The rotor shaft adopts the rotor shaft described above; and / or,

[0021] The stator adopts the stator described above;

[0022] The rotor shaft is inserted into multiple cavities and shaft holes of the stator, and multiple rotor mounting parts on each rotor shaft are correspondingly provided with multiple stages of rotors, and each stage of rotor is accommodated in each cavity of the stator, and each stage of rotors on two rotor shafts mesh with each other to generate compressed gas.

[0023] The present disclosure provides a rotor shaft and a stator for a dry vacuum pump, and a dry vacuum pump, which have the following beneficial effects compared to the prior art: by arranging an outer gas groove on the outer surface of the rotor shaft, or arranging an inner gas groove on the inner surface of the stator shaft hole, the gap of the gas channel changes from small to large and then to small, further causing the gas pressure to change. The gas pressure changes in a short period of time, so that pulse pressure fluctuations are generated when the exhaust flow passes through the gas channel, forming an oscillating purge gas flow, and the process materials accumulated on the surface of the gas channel will fall off due to the pulse gas fluctuations and flow to the next-level cavity with the gas, so as to solve the problems of easy accumulation of process materials in the gas channel, difficulty in cleaning, poor exhaust when the process materials are seriously accumulated, insufficient vacuum bottom pressure, function attenuation, friction heating of the rotor and the process materials, excessive temperature, thermal expansion of the rotor shaft diameter, and friction, interference, and downtime with the stator aperture in severe cases. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a rotor shaft for a dry vacuum pump according to an embodiment of the present disclosure;

[0025] Figure 2 It is a structural schematic diagram of a rotor shaft, a stator and a rotor for a dry vacuum pump according to another embodiment of the present disclosure;

[0026] Figure 3 For this disclosure Figure 2 A partial enlarged view of the middle A;

[0027] Figure 4 It is a schematic structural diagram of a rotor shaft, a stator and a rotor for a dry vacuum pump according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0029] Unless otherwise specified, the technical terms or scientific terms used in the present disclosure shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The terms "including" or "comprising" used in the present disclosure neither limit the shapes, numbers, steps, actions, operations, components, originals and / or groups thereof mentioned, nor exclude the presence or addition of one or more other different shapes, numbers, steps, actions, operations, components, originals and / or groups thereof. In addition, the terms "first" and "second" are used only for descriptive purposes and shall not be understood as indicating or implying relative importance or implicitly indicating the number and order of the indicated technical features.

[0030] In some descriptions of the present disclosure, unless otherwise clearly specified and limited, the terms "install", "connect", "connected" or "fixed" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect through an intermediate medium, and may be internal connections between two elements or mutual interactions between two elements. Also, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, are only used to indicate relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] like Figures 1 to 4 As shown, in one aspect of the present disclosure, a rotor shaft 100 for a dry vacuum pump is proposed, wherein the rotor shaft 100 has a plurality of rotor mounting portions spaced apart along its length direction, and an air passage portion located between any two adjacent rotor mounting portions; wherein the plurality of rotor mounting portions are used to mount a multi-stage rotor, and at least one outer air passage groove is provided in a middle region of an outer wall of at least one air passage portion; a gap between an outer wall of the air passage portion and an inner wall of an axial hole of a stator 200 forms an air passage 400, and the gap in a middle region of the air passage 400 is changed through the outer air passage groove, so that when the compressed gas in the upper-stage cavity flows to the lower-stage rotor cavity through the air passage 400, the change in the gap in the middle region of the air passage 400 causes a change in gas pressure, so that the gas generates a pulse pressure fluctuation when passing through the air passage 400, thereby forming an oscillating purge gas flow.

[0032] In the present embodiment, since an outer gas groove is provided in the middle area of ​​the gas passage, the outer gas groove increases the gap in the middle area of ​​the gas passage, that is, the gap in the middle area of ​​the gas passage is larger than the gaps in the two side areas, so that the gap of the gas passage changes from small to large and then from large to small in the gas flow direction. Under the premise that the exhaust volume of the compressed gas in the cavity is the same, when the gap of the gas passage changes from small to large when flowing through the gas passage, the gas pressure decreases. Then, when the gap of the gas passage changes from large to small again, the gas pressure increases. The gas pressure changes in a short time, so that pulse pressure fluctuations are generated when the exhaust flow passes through the gas passage, forming an oscillating purge gas flow. The oscillating purge gas flow can make the process materials accumulated on the surface of the gas passage fall off due to the pulse gas fluctuations and flow to the next-level cavity with the gas, so as to clean the process materials accumulated in the gas passage, keep the gas passage unobstructed, avoid the friction and heating of the rotor and the process materials, and effectively improve the operation efficiency and life of the rotor shaft.

[0033] It should be noted that the present embodiment does not specifically limit the location of the external gas passage groove. For example, when the rotor shaft has two rotor mounting parts spaced apart along the length direction thereof, there is only one gas passage part, and the corresponding external gas passage groove is arranged on the gas passage part. For another example, when the rotor shaft has three, four, five or more rotor mounting parts spaced apart along the length direction thereof, there are two, three, four or more gas passage parts, and the external gas passage groove can be arranged on any one of the multiple gas passage parts, or on multiple gas passage parts, or on all gas passage parts, so as to increase the purge area and purge capacity of the deposits.

[0034] For example, Figure 1 and Figure 2 As shown, the rotor shaft 100 has five rotor mounting parts, and a corresponding rotor is arranged on each rotor mounting part, namely a first-stage rotor 310, a second-stage rotor 320, a third-stage rotor 330, a fourth-stage rotor 340 and a fifth-stage rotor 350. A first outer gas passage groove 110 is arranged on the gas passage part between the first-stage rotor 310 and the second-stage rotor 320, a second outer gas passage groove 120 is arranged on the gas passage part between the second-stage rotor 320 and the third-stage rotor 330, a third outer gas passage groove 130 is arranged on the gas passage part between the third-stage rotor 330 and the fourth-stage rotor 340, and a fourth outer gas passage groove 140 is arranged on the gas passage part between the fourth-stage rotor 340 and the fifth-stage rotor 350.

[0035] It should be further explained that the present embodiment does not impose any specific limitation on the specific structure of the external gas passage groove, as long as the gap of the gas passage can be changed and the gas can form an oscillating purge gas source.

[0036] In some preferred embodiments, Figure 1 and Figure 2 As shown, the outer gas passage groove is arranged circumferentially around the outer wall of the rotor shaft 100, that is, a circle of grooves is opened on the outer circumferential wall of the rotor shaft 100 to form the outer gas passage groove, which is a continuous annular groove structure. Figure 3 As shown, after the gas passage 400 is formed by the outer wall of the rotor shaft 100 and the inner wall of the shaft hole of the stator 200, along the gas flow direction, the gas passage 400 includes a front channel 410, a middle channel 420 and a rear channel 430, wherein the gap of the middle channel 420 is larger than the gaps between the front channel 410 and the rear channel 430.

[0037] It should be understood that, in addition to the above-mentioned configuration of the outer gas passage groove as a continuous annular groove, the outer gas passage groove may also be divided into a plurality of sub-grooves, and the plurality of sub-grooves are spaced apart on the outer peripheral wall of the rotor shaft.

[0038] It should still be noted that the present embodiment does not impose any specific limitation on the number of external air passage grooves on any air passage portion, and can be specifically set according to the width of the air passage portion. When the width of the air passage portion is small, one external air passage groove can be set, and when the width of the air passage portion is large, two, three or other numbers of external air passage grooves can be set.

[0039] In some preferred embodiments, an outer gas passage groove is provided in the middle region of each gas passage portion.

[0040] In some other preferred embodiments, a plurality of outer gas passage grooves are provided in the middle region of each gas passage portion.

[0041] It should be understood that when a plurality of external gas passage grooves are provided on the gas passage portion, the intermediate channel included in the gas passage should be formed by a plurality of external grooves arranged at intervals. At this time, along the gas flow direction, the gap of the gas passage changes from small to large and then from large to small many times. The gas pressure changes many times in a short period of time, generating stronger pulse pressure fluctuations to purge the process materials accumulated on the rotor shaft.

[0042] It should be noted that the present embodiment does not specifically limit the width of the external gas passage groove. Of course, its width should be smaller than the width of the gas passage portion. Preferably, the width of the external gas passage groove is less than or equal to 1 / 3 of the width of the gas passage portion. For example, when only one external gas passage groove is provided on any gas passage portion, the width of the external gas passage groove is less than or equal to 1 / 3 of the width of the gas passage portion. For another example, when multiple external gas passage grooves are provided on any gas passage portion, the total width of the multiple external gas passage grooves is less than or equal to 1 / 3 of the width of the gas passage portion.

[0043] It should be understood that the maximum width of the outer air passage groove should be 1 / 3 of the width of the air passage portion. In some preferred embodiments, the width of the outer air passage groove is less than 1 / 3 of the width of the air passage portion. For example, the width of the outer air passage groove is 1 / 4 of the width of the air passage portion. Of course, outer air passage grooves of other width sizes can also be selected.

[0044] It should be noted that the present embodiment does not impose any specific limitation on the depth of the external gas passage groove. For example, the depth of the external gas passage groove is preferably 0.1 to 0.15 mm, for example, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm and other depths.

[0045] In this embodiment, an external gas passage groove is opened in the gas passage portion of the rotor shaft to change the gap of the gas passage, thereby causing a change in gas pressure, so that pulse pressure fluctuations are generated when the exhaust flow passes through the gas passage, forming an oscillating purge gas flow. In this way, the process materials accumulated on the surface of the gas passage will fall off due to the pulse gas fluctuations and flow to the next stage with the gas, thereby solving the problems of process materials being easy to accumulate in the gas passage and difficult to be cleaned, and serious accumulation of process materials leading to poor exhaust, insufficient vacuum bottom pressure, functional attenuation, frictional heating of the rotor and the process materials, excessive temperature, thermal expansion of the rotor shaft diameter, and serious friction, interference, and shutdown with the stator aperture.

[0046] like Figures 2 to 4 As shown, another aspect of the present disclosure provides a stator 200 for a dry vacuum pump, wherein the stator 200 has a plurality of cavities for accommodating a multi-stage rotor and spaced apart along its length direction, and an axial hole located between any two adjacent cavities; wherein at least one inner air passage groove is provided in the middle region of the inner wall of at least one axial hole; the inner wall of the stator axial hole can form an air passage 400 with the air passage portion on the rotor shaft 100, and the inner air passage groove changes the gap in the middle region of the air passage, so that when the compressed gas generated by the meshing of the upper stage rotor flows through the air passage to the next stage rotor cavity, a pulse pressure fluctuation is generated to form an oscillating purge airflow.

[0047] It should be understood that the gas passage is formed by the gap between the outer wall of the rotor shaft and the inner wall of the stator shaft hole. In addition to setting an outer gas passage groove on the outer wall of the rotor shaft, an inner gas passage groove can also be set on the inner wall of the stator shaft hole. Similarly, the gap in the middle area of ​​the gas passage can be increased, so that the gap of the gas passage changes in a "convex" shape, and the gas pressure changes in a short time, so that the exhaust flow generates pulse pressure fluctuations when passing through the gas passage, forming an oscillating purge gas flow, thereby achieving the purge of process materials accumulated on the surface of the gas passage.

[0048] It should be noted that the present embodiment also does not specifically limit the location of the inner air groove. The inner air groove may be set on the inner wall of one of the axial holes, or on the inner walls of multiple axial holes, or on the inner walls of all axial holes.

[0049] It should be further explained that the specific structure of the inner gas passage groove is not specifically limited in this embodiment, as long as the gap of the gas passage can be changed and the gas can form an oscillating purge gas source. For example, the inner gas passage groove is arranged circumferentially around the inner wall of the stator shaft hole, that is, a circle of continuous grooves is opened along the inner circumferential wall of the stator shaft hole to form the inner gas passage groove, so that the gap of the middle channel included in the gas passage is larger than the gap of the front channel and the gap of the rear channel.

[0050] It should still be noted that the present embodiment does not impose any specific limitation on the number of internal air grooves on any axial hole, and can be specifically set according to the width of the axial hole. When the width of the axial hole is small, one external air groove can be set, and when the width of the axial hole is large, two, three or other numbers of internal air grooves can be set.

[0051] It should be noted that the present embodiment does not specifically limit the width of the inner air passage groove. Of course, its width should be smaller than the width of the shaft hole. Preferably, the width of the inner air passage groove is less than or equal to 1 / 3 of the width of the shaft hole. For example, when only one inner air passage groove is provided on the inner wall of any shaft hole, the width of the inner air passage groove is less than or equal to 1 / 3 of the width of the shaft hole. For another example, when multiple inner air passage grooves are provided inside any shaft hole, the total width of the multiple inner air passage grooves is less than or equal to 1 / 3 of the width of the shaft hole.

[0052] Similarly, the maximum width of the inner air groove should be 1 / 3 of the width of the axial hole. In some preferred embodiments, the width of the inner air groove is less than 1 / 3 of the width of the axial hole. For example, the width of the inner air groove is 1 / 4 or 1 / 5 of the width of the axial hole. Of course, inner air grooves of other width sizes can also be selected.

[0053] It should be noted that the present embodiment does not specifically limit the depth of the inner gas groove. For example, the depth of the inner gas groove is preferably 0.1-0.15 mm, for example, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm and other depths.

[0054] like Figures 2 to 4As shown, another aspect of the present disclosure provides a dry vacuum pump, which includes a stator 200, a multi-stage rotor and two rotor shafts 100. The axes of the two rotor shafts are arranged parallel to each other, and the rotor shaft can be the rotor shaft described above, and the stator can also be the stator described above. Please refer to the above description for the specific structure, which will not be repeated here.

[0055] Specifically, Figures 2 to 4 As shown, the rotor shaft 100 is inserted into multiple cavities and shaft holes of the stator 200, and multiple rotor mounting portions on each rotor shaft 100 are correspondingly provided with multi-stage rotors, and each stage of the rotor is accommodated in each stage of the cavity of the stator 200. In this way, when the dry vacuum pump starts to work, each stage of the rotor is excited to start rotating around the stator. During the rotation, the two rotor shafts 100 rotate in opposite directions, and each stage of the rotors arranged on the two rotor shafts 100 mesh with each other. The generated compressed gas flows into the next stage of the cavity through the gas passage, and the gas is discharged to the stator exhaust hole through the multi-stage rotor.

[0056] It should be noted that the present embodiment does not specifically limit the type of rotor, and it can be a Roots rotor or a claw rotor. For example, when the rotors are all claw rotors, a claw-type dry vacuum pump with a multi-stage rotor connected in series is formed, and when the rotors are a mixture of a Roots rotor and a claw rotor, a multi-stage dry vacuum pump with a Roots rotor and a multi-stage rotor connected in series is formed.

[0057] It should be understood that in the vacuum pump of this embodiment, a rotor shaft provided with external gas grooves can be combined with a conventional stator, a stator provided with internal gas grooves can be combined with a conventional rotor shaft, or a rotor shaft provided with external gas grooves can be combined with a stator provided with internal gas grooves to form a gas passage with a larger gap, thereby improving the purging capacity of the purge gas flow and cleaning the process materials accumulated in the gas passage.

[0058] The structure of the rotor shaft and the stator will be described below in conjunction with specific embodiments:

[0059] Example 1

[0060] like Figures 1 to 4As shown, the vacuum pump includes two rotor shafts 100, a stator 200, and ten rotors. The two rotor shafts 100 are respectively a driving shaft 101 and a driven shaft 102, and the driving shaft 101 and the driven shaft 102 have a first rotor mounting portion, a second rotor mounting portion, a third rotor mounting portion, a fourth rotor mounting portion, and a fifth rotor mounting portion along their length direction, and four gas passage portions located between the five rotor mounting portions, namely, a first gas passage portion, a second gas passage portion, a third gas passage portion, and a fourth gas passage portion, and the first outer gas passage groove 110, the second outer gas passage groove 120, the third outer gas passage groove 130, and the fourth outer gas passage groove 140 are respectively arranged on the above four gas passage portions.

[0061] For further information, please refer to Figures 1 to 4 The first rotor mounting portion, the second rotor mounting portion, the third rotor mounting portion, the fourth rotor mounting portion and the fifth rotor mounting portion on the driving shaft 101 and the driven shaft 102 are respectively provided with a first-stage rotor 310, a second-stage rotor 320, a third-stage rotor 330, a fourth-stage rotor 340 and a fifth-stage rotor 350.

[0062] For further information, please refer to Figures 1 to 4 The stator 200 has a first cavity 210, a second cavity 220, a third cavity 230, a fourth cavity 240 and a fifth cavity 250 along its length direction, and four axial holes located between the five cavities, namely the first axial hole, the second axial hole, the third axial hole and the fourth axial hole.

[0063] For further information, please refer to Figures 1 to 4 When the driving shaft 101 and the driven shaft 102 are installed in the stator 200, the first-stage rotor 310 provided on the driving shaft 101 and the driven shaft 102 is accommodated in the first cavity 210, the second-stage rotor 320 provided on the driving shaft 101 and the driven shaft 102 is accommodated in the second cavity 220, the third-stage rotor 330 provided on the driving shaft 101 and the driven shaft 102 is accommodated in the third cavity 230, the fourth-stage rotor 340 provided on the driving shaft 101 and the driven shaft 102 is accommodated in the fourth cavity 240, and the fifth-stage rotor 350 provided on the driving shaft 101 and the driven shaft 102 is accommodated in the fifth cavity 250. In addition, the first air passage portion on the driving shaft 101 and the driven shaft 102 is correspondingly inserted into the first axial hole on the stator, and the gap between the two forms the first air passage; the second air passage portion is inserted into the second axial hole on the stator, and the gap between the two forms the second air passage; the third air passage portion is inserted into the third axial hole on the stator, and the gap between the two forms the third air passage; the fourth air passage portion is inserted into the fourth axial hole on the stator, and the gap between the two forms the fourth air passage.

[0064] For further information, please refer to Figures 2 to 4 Based on the above structure, when the vacuum pump is running, the compressed gas generated by the mutual meshing of the two primary rotors 310 on the driving shaft 101 and the driven shaft 102 flows into the second cavity 220 through the first gas passage. Afterwards, the compressed gas generated by the mutual meshing of the two secondary rotors 320 on the driving shaft 101 and the driven shaft 102 flows into the third cavity 230 through the second gas passage. Afterwards, the compressed gas generated by the mutual meshing of the two tertiary rotors 330 on the driving shaft 101 and the driven shaft 102 flows into the fourth cavity 240 through the third gas passage. Afterwards, the compressed gas generated by the mutual meshing of the two fourth-stage rotors 340 on the driving shaft 101 and the driven shaft 102 flows into the fifth cavity 250 through the fourth gas passage. Afterwards, the compressed gas generated by the mutual meshing of the two fifth-stage rotors 350 on the driving shaft 101 and the driven shaft 102 is discharged through the exhaust hole on the stator 200.

[0065] It should be understood that the above-mentioned first gas passage, second gas passage, third gas passage, fourth gas passage and fifth gas passage all include a front channel, a middle channel and a rear channel, wherein the gap of the middle channel is larger than the gap between the front channel and the rear channel. Thus, when the compressed gas in the upper-level cavity passes through the gas passage, the gap of the gas passage will change from small to large and then to small, so that the exhaust flow will generate pulse pressure fluctuations when passing through the gas channel, forming an oscillating purge gas flow, and the process materials accumulated on the surface of the gas passage will fall off due to the pulse gas fluctuations and flow to the next level with the gas.

[0066] It should be noted that this embodiment only takes the example of providing an external air groove on the rotor shaft for explanation. Those skilled in the art should know that an internal air groove may also be provided on the inner wall of the stator shaft hole as required, and no specific limitation is made to this.

[0067] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A rotor shaft for a dry vacuum pump, characterized in that: The rotor shaft has a plurality of rotor mounting portions for mounting a multi-stage rotor and spaced apart along its length direction, and a gas passage portion located between any two adjacent rotor mounting portions; wherein, At least one outer gas passage groove is provided in the middle area of ​​the outer wall of at least one of the gas passage portions; The air passage portion can form an air passage with the inner wall of the stator shaft hole, and the outer air passage groove changes the gap in the middle area of ​​the air passage, so that when the compressed gas generated by the meshing of the upper-stage rotor flows through the air passage to the next-stage cavity, an oscillating purge airflow is formed.

2. The rotor shaft according to claim 1, characterized in that The outer air passage groove is circumferentially arranged around the outer wall of the rotor shaft.

3. The rotor shaft according to claim 1, characterized in that The width of the at least one outer gas passage groove is less than or equal to 1 / 3 of the width of the gas passage portion.

4. The rotor shaft according to claim 1, characterized in that The depth of the outer air passage groove is 0.1-0.15 mm.

5. The rotor shaft according to any one of claims 1 to 4, characterized in that The gap in the middle area of ​​the gas passage is larger than the gaps in the two side areas.

6. A stator for a dry vacuum pump, characterized in that: The stator has a plurality of cavities spaced apart along its length direction for accommodating a multi-stage rotor, and an axial hole located between any two adjacent cavities; wherein, At least one inner air passage groove is provided in the middle area of ​​the inner wall of at least one of the shaft holes; The inner wall of the stator shaft hole can form an air passage with the air passage portion on the rotor shaft, and the inner air passage groove changes the gap in the middle area of ​​the air passage, so that when the compressed gas generated by the meshing of the previous stage rotor flows through the air passage to the next stage cavity, an oscillating purge airflow is formed.

7. The stator according to claim 6, characterized in that The inner air-transmitting groove is circumferentially arranged around the inner wall of the stator shaft hole.

8. The stator according to claim 6, characterized in that: The width of the at least one inner air passage groove is less than or equal to 1 / 3 of the width of the stator shaft hole.

9. The stator according to claim 6, characterized in that: The depth of the inner air passage groove is 0.1-0.15 mm.

10. A dry vacuum pump, characterized in that: The dry vacuum pump comprises a stator, a multi-stage rotor and two rotor shafts; wherein, The rotor shaft adopts the rotor shaft according to any one of claims 1 to 5; and / or, The stator adopts the stator according to any one of claims 6 to 9; The rotor shaft is inserted into multiple cavities and shaft holes of the stator, and multiple rotor mounting parts on each rotor shaft are correspondingly provided with multiple stages of rotors, and each stage of rotor is accommodated in each cavity of the stator, and each stage of rotors on two rotor shafts mesh with each other to generate compressed gas.

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