CN106678041B - A kind of outer balance type screw vacuum pump - Google Patents

Abstract

The invention belongs to dry vacuum pump technical fields, and in particular to a kind of outer balance type screw vacuum pump.Technical scheme is as follows：A kind of outer balance type screw vacuum pump, including motor, the pump housing, gear-box two, speed increasing gear train, synchronous gear wheel set, power rotor and driven rotor, the pump housing is equipped with gear-box one, and the motor and gear-box two are separately positioned on the both ends of the pump housing；The power rotor and driven rotor are arranged in the pump housing；The speed increasing gear train and synchronous gear wheel set are mounted on the both ends of the power rotor and driven rotor；The speed increasing gear train is arranged in gear-box one, and the synchronous gear wheel set is arranged in gear-box two.Outer balance type screw vacuum pump provided by the invention, it is therefore intended that while improving the axially loaded equilibrium problem of screw vacuum pump, realize that screw vacuum pump discharge zero is lost, gear and transition axis connecting mode, compact-sized, stable drive are arranged using bilateral.

Description

An externally balanced screw vacuum pump

technical field

The invention belongs to the technical field of dry vacuum pumps, in particular to an externally balanced screw vacuum pump.

Background technique

With the vigorous development of the electronics industry, chemical industry, film industry, and freeze-drying, more and more industries require a clean vacuum environment without oil vapor as their production basis, so the market demand for dry pumps is also increasing. more urgent.

The research on the screw type dry vacuum pump was originally intended to be used in the semiconductor industry and the liquid crystal display manufacturing industry. Japan, Germany, the United States, and Taiwan are all countries and regions that carried out research and development work earlier. Nowadays, the screw dry vacuum pump is widely used in electronics, nuclear energy, chemical industry, medicine, food industry, etc. field.

In order to achieve the purpose of improving the pumping performance of the screw vacuum pump, optimizing the screw compression capacity, and reducing the thermal deformation of the rotor, researchers have developed the following typical screw vacuum pump structures with improved structures:

The Chinese patent application number 200910098378.9 discloses a screw vacuum pump with twin-screw structure, one of which is a three-start screw, and the other is a double-start screw, and the profile and meshing curve of the two screws are given . Through this design, every time one stage is added, only the length of the double-ended screw needs to be increased by half of the lead, and the relative length of the screw is relatively short, with high efficiency, stable operation and low noise. However, due to the asymmetrical rotor, there are certain difficulties in processing, the processing is complicated, and the cost is high.

The Chinese patent with publication number CN 102979731 B discloses a twin-screw vacuum pump rotor profile and design method. The profile determined by this design method has a closed meshing line and a continuous contact line, the area of the through hole is small, the volumetric efficiency is high, and the processing of the formed profile is relatively simple, and the processing cost is low. However, how to balance the axial force of the screw , no better solution was proposed.

The Chinese patent with application number 201410261216.3 discloses a new type of twin-screw vacuum pump, which uses two screws with different diameters. Compared with a screw with the same diameter and the same number of turns, the sealing line formed is twice as large and the ultimate vacuum formed is improved. Spend. However, due to the different diameters, the volume of the sealing cavity changes, resulting in a decrease in the flow rate, and the force on the two screws will also be different, making it difficult to balance.

The Chinese patent with the publication number CN 102937094 B discloses a variable-pitch screw of a dry-type screw vacuum pump, which uses a variable-pitch screw instead of an equal-pitch screw. Equipped with this type of vacuum pump, it provides the best choice for reducing energy requirements, reducing noise, reducing internal operating temperature, reducing structural space and reducing manufacturing costs. However, due to the internal compression, the gas must have a force on the rotor, and how to reduce the gas force has not been considered in this patent.

The Chinese patent with the publication number CN 103062056 B discloses a screw-type dry vacuum pump with a combined screw rotor. Through the combination of multi-section hollow screw rotor pieces, a screw vacuum pump with equal pitch and a screw vacuum pump with variable pitch can be formed. It is also possible to combine the advantages of both, which enriches product categories and reduces manufacturing and maintenance costs. However, the hollow screw rotor slices at all levels are connected to the shaft by bolts, and the increase of connection parts reduces the reliability of the equipment, and the screw rotor has poor adaptability to thermal deformation.

The Chinese patent with the publication number CN 203308712 U discloses a variable-pitch double-head screw vacuum pump. The rotor of the variable-pitch double-head screw vacuum pump is a variable-pitch double-head screw rotor, and the pitch of the rotor is from the suction port to the exhaust port. The difference sequence decreases, which improves the pumping efficiency, reduces the exhaust noise and exhaust temperature, and the center of mass of any cross section of the rotor is located at the geometric center, which is easy to achieve dynamic balance, has low noise, and has a certain balance effect on the force of the rotor .

The Chinese patent with publication number CN 103267015 A discloses a dry-type screw vacuum pump cooled in a heat pipe. It designs the rotor as a hollow structure with a cooling cavity inside, which is convenient for cooling the screw and taking away the heat. At the same time, the position of the exhaust port is changed to discharge the solid and liquid mixed in the gas medium pumping, which improves the performance of the screw pump. reliability and working life.

The U.S. patent with the publication number US7214036B2 discloses a screw vacuum pump. The screw is designed as a three-segment helical tooth, and a bypass and a check valve are arranged in the middle area of each two-segment helical tooth. The gas can be effectively avoided through such a passage. The phenomenon of overcompression occurs, so the axial force given by the gas is greatly weakened. However, no solution is proposed for the axial unbalanced force generated by the screw external transmission gear.

The U.S. Patent Publication No. US6382930B1 discloses a combined rotor screw vacuum pump. The suction side and the exhaust side are manufactured separately. The suction side can be made of general metals such as aluminum, and the exhaust side can be made of high-performance materials such as stainless steel. The entire root shaft It is hollow, with circulating coolant, powered by a cooling pump. This design method reduces material and processing costs under the condition of meeting the use requirements, and through internal cooling, excessive heat is taken away, reducing thermal deformation of the rotor. However, since the rotor is connected by two parts of the rotor, the reliability of the equipment is reduced; the shaft as a whole is a hollow shaft, which requires the material of the shaft to meet high requirements.

The U.S. patent with the publication number US6371744B1 discloses a screw vacuum pump, in which the screw rotor and the pump body are made of nickel-containing ductile iron, which enhances the corrosion resistance and thermal conductivity of the rotor, and ensures the accuracy of dimensions during meshing. However, the mechanical properties of this material are poor when the screw length is too long. For example, when it is larger than five times its diameter, the axis is prone to bending, causing fit problems.

Through the investigation of the above-mentioned existing typical screw pumps, it can be seen that although they have all improved the screw, the key component of the screw pump, the axial force of the screw has been improved, and the stability of the screw pump has been enhanced. However, in further balancing the operation of the whole pump There is a certain limit to the axial force generated at the time.

Contents of the invention

The invention provides an externally balanced screw vacuum pump, which aims to improve the axial force balance of the screw vacuum pump and at the same time realize zero flow loss of the screw vacuum pump. It adopts a double-sided arrangement of gears and a transition shaft connection mode, which has a compact structure and stable transmission.

Technical scheme of the present invention is as follows:

An externally balanced screw vacuum pump, comprising a motor, a pump body, a second gear box, a speed-increasing gear pair, a synchronous gear pair, a driving rotor and a driven rotor, the pump body is provided with a gear box one, and the motor and the gear box Two are respectively arranged at both ends of the pump body; the driving rotor and the driven rotor are arranged in the pump body; the speed-increasing gear pair and the synchronous gear pair are installed at both ends of the driving rotor and the driven rotor ; The speed-increasing gear pair is set in the first gear box, and the synchronous gear pair is set in the second gear box.

The externally balanced screw vacuum pump, wherein the speed-up gear pair includes a speed-up gear and a speed-up pinion, the speed-up gear meshes with the speed-up pinion, and one protruding end of the driven rotor is equipped with The supporting bearing, the speed-increasing large gear is installed together with the supporting bearing; the transition shaft is installed on the speed-increasing large gear, and the motor is connected with the transition shaft through a shaft coupling.

The externally balanced screw vacuum pump, wherein the synchronous gear pair includes a synchronous gear 1 and a synchronous gear 2, the synchronous gear 1 meshes with the synchronous gear 2, the synchronous gear 1 is installed on the driving rotor, and the synchronous gear 2 is installed on the on the driven rotor.

The preferred solution of the externally balanced screw vacuum pump is that angular contact ball bearings are provided between the driving rotor, the driven rotor and the pump body, and mechanical shaft seals are used.

The preferred solution of the externally balanced screw vacuum pump is that the speed-increasing large gear and the supporting bearing are connected through expansion sleeves.

The preferred solution of the externally balanced screw vacuum pump is that the speed-increasing gear pair and the synchronizing gear pair are helical gears.

The preferred solution of the externally balanced screw vacuum pump is that the length of the driving rotor and the driven rotor are equal.

The preferred solution of the externally balanced screw vacuum pump is that the driving rotor and the driven rotor are of equal pitch or variable pitch.

The preferred solution of the externally balanced screw vacuum pump is that the pump body is integrally cast.

The preferred solution of the externally balanced screw vacuum pump is that the second gear box is provided with a rear cover.

The beneficial effects of the present invention are: the present invention arranges the speed-increasing gear and the transmission gear on both sides of the screw rotor, and the speed-increasing large gear and the meshing rotor are located on the same shaft, which effectively reduces the overall size of the entire pump body and balances the gear transmission. Axial force generated when engaging with the rotor and pumping air. It adopts double-sided arrangement of gears and transition shaft connection, which has the advantages of compact structure and stable transmission. The present invention overcomes the predicament of improving the axial force by designing the screw, and introduces the balancing measures of the axial force outside the pump chamber without affecting the pumping performance of the screw pump and the processing difficulty of the screw, starting from the transmission pair, and reasonably arranging The position of the transmission pair and the type of the transmission pair are selected to achieve the purpose of maximally balancing the axial force and making the operation more stable.

Description of drawings

Figure 1 is a schematic structural diagram of an externally balanced screw vacuum pump;

Fig. 2 is a schematic diagram of the connection of the transition shaft and the speed-increasing large gear;

Figure 3a is a schematic diagram of the axial force of the existing screw vacuum pump;

Fig. 3b is a schematic diagram of the axial force of the externally balanced screw vacuum pump.

Detailed ways

As shown in Figures 1 and 2, an externally balanced screw vacuum pump includes a motor 1, a pump body 7, a gearbox 2 8, a speed-increasing gear pair, a synchronous gear pair, a driving rotor 12 and a driven rotor 6. The pump The body 7 is provided with a gear box one, and the motor 1 and the gear box two 8 are respectively arranged at both ends of the pump body 7; the driving rotor 12 and the driven rotor 6 are arranged in the pump body 7; The speed-increasing gear pair and the synchronous gear pair are installed at the two ends of the driving rotor 12 and the driven rotor 6; the speed-increasing gear pair is arranged in the first gear box, and the synchronous gear pair is arranged in the second gear box 8; Wherein the speed-up gear pair includes a speed-up gear 4 and a speed-up pinion 14, the speed-up gear 4 meshes with the speed-up pinion 14, and a support bearing 5 is housed on an extended end of the driven rotor 6, Speed-up bull gear 4 is installed together with described supporting bearing 5; Transition shaft 3 is installed on speed-speed bull gear 4, and described motor 1 is connected together with described transition shaft 3 through coupling 2; Wherein the synchronous gear The auxiliary bar includes a synchronous gear 11 and a synchronous gear 2 16, the synchronous gear 11 meshes with the synchronous gear 2 16, the synchronous gear 11 is installed on the driving rotor 12, and the synchronous gear 2 16 is installed on the driven rotor 6 An angular contact ball bearing 9 is provided between the driving rotor 12 and the driven rotor 6 and the pump body 7, and a mechanical shaft seal 13 is used; the speed-increasing large gear 4 and the support bearing 5 are connected through an expansion sleeve 15; The speed-increasing gear pair and the synchronous gear pair are helical gears; the length of the driving rotor 12 and the driven rotor 6 are equal; the driving rotor 12 and the driven rotor 6 are of equal pitch; the pump body 7 is integrally cast , take the horizontal type, lower the center of gravity, and increase the smooth operation; the second gear box 8 is provided with a rear cover 10. The power of the motor 1 makes the driving rotor (12) obtain torque through the engagement of the speed increasing gear (4) and the speed increasing pinion (14), thereby driving the driven rotor (6) to rotate through the transmission gear pair to realize the driving rotor ( 12) Engage air extraction with driven rotor (6).

As shown in Figure 3a, when the transmission gear is only arranged on one side, the overall axial resultant force of the driving rotor (12) is: T ₁ =F ₁ -F _gas /2;

The overall axial resultant force of the driven rotor (6) is: T ₂ =-F' ₁ -F _gas /2;

As shown in Figure 3b, when the speed-up gear and transmission gear are arranged on both sides, the overall axial resultant force of the driving rotor (12) is: T ₁ =-F' ₁ -F _gas /2+F'₂;

The overall axial force of the driven rotor (6) is: T ₂ =F ₁ -F _gas /2-F'₂;

By comparison, in the arrangement shown in Figure 3b, the axial force balance of the screw is better.

Claims (9)

1. a kind of outer balance type screw vacuum pump, which is characterized in that including the motor, pump housing, gear-box two, speed increasing gear train, same Gear pair, power rotor and driven rotor are walked, the pump housing is equipped with gear-box one, and the motor and gear-box two are separately positioned on The both ends of the pump housing；The power rotor and driven rotor are arranged in the pump housing；The speed increasing gear train and synchronous gear Wheel set is mounted on the both ends of the power rotor and driven rotor；The speed increasing gear train is arranged in gear-box one, described same Step gear pair is arranged in gear-box two；The speed increasing gear train includes speedup gear wheel and speedup pinion gear, speedup gear wheel It is engaged with speedup pinion gear, equipped with spring bearing, speedup gear wheel and the support on an external part of the driven rotor Bearing is installed together；Transition axis is installed, the motor is connected to one by shaft coupling and the transition axis on speedup gear wheel It rises.

2. outer balance type screw vacuum pump according to claim 1, which is characterized in that the synchronous gear wheel set includes synchronous Gear one and synchromesh gear two, synchromesh gear one are engaged with synchromesh gear two, and synchromesh gear one is mounted on the power rotor, Synchromesh gear two is mounted on the driven rotor.

3. outer balance type screw vacuum pump according to claim 1, which is characterized in that the power rotor and driven rotor Angular contact ball bearing is equipped between the pump housing, using mechanical shaft seal.

4. outer balance type screw vacuum pump according to claim 1, which is characterized in that speedup gear wheel leads to spring bearing Cross expansion set connection.

5. outer balance type screw vacuum pump according to claim 1, which is characterized in that the speed increasing gear train and synchronous gear Wheel set is angular gear.

6. outer balance type screw vacuum pump according to claim 1, which is characterized in that the power rotor and driven rotor Equal length.

7. outer balance type screw vacuum pump according to claim 1, which is characterized in that the power rotor and driven rotor For uniform pitch or varying pitch.

8. outer balance type screw vacuum pump according to claim 1, which is characterized in that the pump housing be integrated casting and Into.

9. outer balance type screw vacuum pump according to claim 1, which is characterized in that the gear-box two is equipped with rear cover.